merge with head and resolve conflicts

BUILD

@@ -677,6 +677,9 @@ cc_library(
     "src/cpp/server/secure_server_credentials.h",
     "src/cpp/client/create_channel_internal.h",
     "src/cpp/common/create_auth_context.h",
+    "src/cpp/server/dynamic_thread_pool.h",
+    "src/cpp/server/fixed_size_thread_pool.h",
+    "src/cpp/server/thread_pool_interface.h",
     "src/cpp/client/secure_channel_arguments.cc",
     "src/cpp/client/secure_credentials.cc",
     "src/cpp/common/auth_property_iterator.cc",
@@ -722,8 +725,6 @@ cc_library(
     "include/grpc++/config_protobuf.h",
     "include/grpc++/create_channel.h",
     "include/grpc++/credentials.h",
-    "include/grpc++/dynamic_thread_pool.h",
-    "include/grpc++/fixed_size_thread_pool.h",
     "include/grpc++/generic_stub.h",
     "include/grpc++/impl/call.h",
     "include/grpc++/impl/client_unary_call.h",
@@ -748,7 +749,6 @@ cc_library(
     "include/grpc++/status_code_enum.h",
     "include/grpc++/stream.h",
     "include/grpc++/stub_options.h",
-    "include/grpc++/thread_pool_interface.h",
     "include/grpc++/time.h",
   ],
   includes = [
@@ -768,6 +768,9 @@ cc_library(
   srcs = [
     "src/cpp/client/create_channel_internal.h",
     "src/cpp/common/create_auth_context.h",
+    "src/cpp/server/dynamic_thread_pool.h",
+    "src/cpp/server/fixed_size_thread_pool.h",
+    "src/cpp/server/thread_pool_interface.h",
     "src/cpp/common/insecure_create_auth_context.cc",
     "src/cpp/client/channel.cc",
     "src/cpp/client/channel_arguments.cc",
@@ -808,8 +811,6 @@ cc_library(
     "include/grpc++/config_protobuf.h",
     "include/grpc++/create_channel.h",
     "include/grpc++/credentials.h",
-    "include/grpc++/dynamic_thread_pool.h",
-    "include/grpc++/fixed_size_thread_pool.h",
     "include/grpc++/generic_stub.h",
     "include/grpc++/impl/call.h",
     "include/grpc++/impl/client_unary_call.h",
@@ -834,7 +835,6 @@ cc_library(
     "include/grpc++/status_code_enum.h",
     "include/grpc++/stream.h",
     "include/grpc++/stub_options.h",
-    "include/grpc++/thread_pool_interface.h",
     "include/grpc++/time.h",
   ],
   includes = [

build.json

@@ -42,8 +42,6 @@
         "include/grpc++/config_protobuf.h",
         "include/grpc++/create_channel.h",
         "include/grpc++/credentials.h",
-        "include/grpc++/dynamic_thread_pool.h",
-        "include/grpc++/fixed_size_thread_pool.h",
         "include/grpc++/generic_stub.h",
         "include/grpc++/impl/call.h",
         "include/grpc++/impl/client_unary_call.h",
@@ -68,12 +66,14 @@
         "include/grpc++/status_code_enum.h",
         "include/grpc++/stream.h",
         "include/grpc++/stub_options.h",
-        "include/grpc++/thread_pool_interface.h",
         "include/grpc++/time.h"
       ],
       "headers": [
         "src/cpp/client/create_channel_internal.h",
-        "src/cpp/common/create_auth_context.h"
+        "src/cpp/common/create_auth_context.h",
+        "src/cpp/server/dynamic_thread_pool.h",
+        "src/cpp/server/fixed_size_thread_pool.h",
+        "src/cpp/server/thread_pool_interface.h"
       ],
       "src": [
         "src/cpp/client/channel.cc",
@@ -1364,6 +1364,20 @@
         "gpr"
       ]
     },
+    {
+      "name": "grpc_channel_args_test",
+      "build": "test",
+      "language": "c",
+      "src": [
+        "test/core/channel/channel_args_test.c"
+      ],
+      "deps": [
+        "grpc_test_util",
+        "grpc",
+        "gpr_test_util",
+        "gpr"
+      ]
+    },
     {
       "name": "grpc_channel_stack_test",
       "build": "test",
@@ -2128,21 +2142,6 @@
         "gpr"
       ]
     },
-    {
-      "name": "dynamic_thread_pool_test",
-      "build": "test",
-      "language": "c++",
-      "src": [
-        "test/cpp/server/dynamic_thread_pool_test.cc"
-      ],
-      "deps": [
-        "grpc_test_util",
-        "grpc++",
-        "grpc",
-        "gpr_test_util",
-        "gpr"
-      ]
-    },
     {
       "name": "end2end_test",
       "build": "test",
@@ -2159,21 +2158,6 @@
         "gpr"
       ]
     },
-    {
-      "name": "fixed_size_thread_pool_test",
-      "build": "test",
-      "language": "c++",
-      "src": [
-        "test/cpp/server/fixed_size_thread_pool_test.cc"
-      ],
-      "deps": [
-        "grpc_test_util",
-        "grpc++",
-        "grpc",
-        "gpr_test_util",
-        "gpr"
-      ]
-    },
     {
       "name": "generic_end2end_test",
       "build": "test",
@@ -2623,13 +2607,9 @@
         "grpc++_test_util",
         "grpc_test_util",
         "grpc++",
-        "grpc_zookeeper",
         "grpc",
         "gpr_test_util",
         "gpr"
-      ],
-      "external_deps": [
-        "zookeeper"
       ]
     },
     {

doc/connection-backoff-interop-test-description.md

@@ -31,9 +31,9 @@ Clients should accept these arguments:
 * --server_retry_port=PORT
     * The server port to connect to for testing backoffs. For example, "8081"
 
-The client must connect to the control port without TLS. The client should
+The client must connect to the control port without TLS. The client must connect
-either assert on the server returned backoff status or check the returned
+to the retry port with TLS. The client should either assert on the server
-backoffs on its own.
+returned backoff status or check the returned backoffs on its own.
 
 Procedure of client:
 

doc/connection-backoff.md

@@ -44,3 +44,12 @@ different jitter logic.
 Alternate implementations must ensure that connection backoffs started at the
 same time disperse, and must not attempt connections substantially more often
 than the above algorithm.
+
+## Reset Backoff
+
+The back off should be reset to INITIAL_BACKOFF at some time point, so that the
+reconnecting behavior is consistent no matter the connection is a newly started
+one or a previously disconnected one.
+
+We choose to reset the Backoff when the SETTINGS frame is received, at that time
+point, we know for sure that this connection was accepted by the server.

include/grpc++/impl/call.h

@@ -541,8 +541,7 @@ class CallOpSet : public CallOpSetInterface,
 template <class Op1 = CallNoOp<1>, class Op2 = CallNoOp<2>,
           class Op3 = CallNoOp<3>, class Op4 = CallNoOp<4>,
           class Op5 = CallNoOp<5>, class Op6 = CallNoOp<6>>
-class SneakyCallOpSet GRPC_FINAL
+class SneakyCallOpSet : public CallOpSet<Op1, Op2, Op3, Op4, Op5, Op6> {
-    : public CallOpSet<Op1, Op2, Op3, Op4, Op5, Op6> {
  public:
   bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
     typedef CallOpSet<Op1, Op2, Op3, Op4, Op5, Op6> Base;

include/grpc++/impl/rpc_service_method.h

@@ -211,13 +211,19 @@ class BidiStreamingHandler : public MethodHandler {
 // Handle unknown method by returning UNIMPLEMENTED error.
 class UnknownMethodHandler : public MethodHandler {
  public:
-  void RunHandler(const HandlerParameter& param) GRPC_FINAL {
+  template <class T>
+  static void FillOps(ServerContext* context, T* ops) {
     Status status(StatusCode::UNIMPLEMENTED, "");
-    CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> ops;
+    if (!context->sent_initial_metadata_) {
-    if (!param.server_context->sent_initial_metadata_) {
+      ops->SendInitialMetadata(context->initial_metadata_);
-      ops.SendInitialMetadata(param.server_context->initial_metadata_);
+      context->sent_initial_metadata_ = true;
     }
-    ops.ServerSendStatus(param.server_context->trailing_metadata_, status);
+    ops->ServerSendStatus(context->trailing_metadata_, status);
+  }
+
+  void RunHandler(const HandlerParameter& param) GRPC_FINAL {
+    CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> ops;
+    FillOps(param.server_context, &ops);
     param.call->PerformOps(&ops);
     param.call->cq()->Pluck(&ops);
   }

include/grpc++/server.h

@@ -98,7 +98,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
   // Add a listening port. Can be called multiple times.
   int AddListeningPort(const grpc::string& addr, ServerCredentials* creds);
   // Start the server.
-  bool Start();
+  bool Start(ServerCompletionQueue** cqs, size_t num_cqs);
 
   void HandleQueueClosed();
   void RunRpc();
@@ -112,7 +112,8 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
    public:
     BaseAsyncRequest(Server* server, ServerContext* context,
                      ServerAsyncStreamingInterface* stream,
-                     CompletionQueue* call_cq, void* tag);
+                     CompletionQueue* call_cq, void* tag,
+                     bool delete_on_finalize);
     virtual ~BaseAsyncRequest();
 
     bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
@@ -123,6 +124,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
     ServerAsyncStreamingInterface* const stream_;
     CompletionQueue* const call_cq_;
     void* const tag_;
+    const bool delete_on_finalize_;
     grpc_call* call_;
     grpc_metadata_array initial_metadata_array_;
   };
@@ -184,12 +186,13 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
     Message* const request_;
   };
 
-  class GenericAsyncRequest GRPC_FINAL : public BaseAsyncRequest {
+  class GenericAsyncRequest : public BaseAsyncRequest {
    public:
     GenericAsyncRequest(Server* server, GenericServerContext* context,
                         ServerAsyncStreamingInterface* stream,
                         CompletionQueue* call_cq,
-                        ServerCompletionQueue* notification_cq, void* tag);
+                        ServerCompletionQueue* notification_cq, void* tag,
+                        bool delete_on_finalize);
 
     bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
 
@@ -197,6 +200,10 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
     grpc_call_details call_details_;
   };
 
+  class UnimplementedAsyncRequestContext;
+  class UnimplementedAsyncRequest;
+  class UnimplementedAsyncResponse;
+
   template <class Message>
   void RequestAsyncCall(void* registered_method, ServerContext* context,
                         ServerAsyncStreamingInterface* stream,
@@ -221,7 +228,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
                                ServerCompletionQueue* notification_cq,
                                void* tag) {
     new GenericAsyncRequest(this, context, stream, call_cq, notification_cq,
-                            tag);
+                            tag, true);
   }
 
   const int max_message_size_;

include/grpc++/server_builder.h

@@ -96,13 +96,9 @@ class ServerBuilder {
                         std::shared_ptr<ServerCredentials> creds,
                         int* selected_port = nullptr);
 
-  // Set the thread pool used for running appliation rpc handlers.
-  // Does not take ownership.
-  void SetThreadPool(ThreadPoolInterface* thread_pool);
-
   // Add a completion queue for handling asynchronous services
-  // Caller is required to keep this completion queue live until calling
+  // Caller is required to keep this completion queue live until
-  // BuildAndStart()
+  // the server is destroyed.
   std::unique_ptr<ServerCompletionQueue> AddCompletionQueue();
 
   // Return a running server which is ready for processing rpcs.

include/grpc++/stream.h

@@ -761,6 +761,8 @@ class ServerAsyncReaderWriter GRPC_FINAL : public ServerAsyncStreamingInterface,
   }
 
  private:
+  friend class ::grpc::Server;
+
   void BindCall(Call* call) GRPC_OVERRIDE { call_ = *call; }
 
   Call call_;

include/grpc/compression.h

@@ -36,12 +36,15 @@
 
 #include <stdlib.h>
 
+#include <grpc/support/port_platform.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /** To be used in channel arguments */
 #define GRPC_COMPRESSION_ALGORITHM_ARG "grpc.compression_algorithm"
+#define GRPC_COMPRESSION_ALGORITHM_STATE_ARG "grpc.compression_algorithm_state"
 
 /* The various compression algorithms supported by GRPC */
 typedef enum {
@@ -60,6 +63,11 @@ typedef enum {
   GRPC_COMPRESS_LEVEL_COUNT
 } grpc_compression_level;
 
+typedef struct grpc_compression_options {
+  gpr_uint32 enabled_algorithms_bitset; /**< All algs are enabled by default */
+  grpc_compression_algorithm default_compression_algorithm; /**< for channel */
+} grpc_compression_options;
+
 /** Parses the first \a name_length bytes of \a name as a
  * grpc_compression_algorithm instance, updating \a algorithm. Returns 1 upon
  * success, 0 otherwise. */
@@ -67,9 +75,7 @@ int grpc_compression_algorithm_parse(const char *name, size_t name_length,
                                      grpc_compression_algorithm *algorithm);
 
 /** Updates \a name with the encoding name corresponding to a valid \a
- * algorithm. Note that the string returned through \a name upon success is
+ * algorithm.  Returns 1 upon success, 0 otherwise. */
- * statically allocated and shouldn't be freed. Returns 1 upon success, 0
- * otherwise. */
 int grpc_compression_algorithm_name(grpc_compression_algorithm algorithm,
                                     char **name);
 
@@ -85,6 +91,20 @@ grpc_compression_level grpc_compression_level_for_algorithm(
 grpc_compression_algorithm grpc_compression_algorithm_for_level(
     grpc_compression_level level);
 
+void grpc_compression_options_init(grpc_compression_options *opts);
+
+/** Mark \a algorithm as enabled in \a opts. */
+void grpc_compression_options_enable_algorithm(
+     grpc_compression_options *opts, grpc_compression_algorithm algorithm);
+
+/** Mark \a algorithm as disabled in \a opts. */
+void grpc_compression_options_disable_algorithm(
+    grpc_compression_options *opts, grpc_compression_algorithm algorithm);
+
+/** Returns true if \a algorithm is marked as enabled in \a opts. */
+int grpc_compression_options_is_algorithm_enabled(
+    const grpc_compression_options *opts, grpc_compression_algorithm algorithm);
+
 #ifdef __cplusplus
 }
 #endif

include/grpc/grpc_security.h

@@ -275,12 +275,18 @@ int grpc_auth_context_set_peer_identity_property_name(grpc_auth_context *ctx,
 /* --- Auth Metadata Processing --- */
 
 /* Callback function that is called when the metadata processing is done.
-   success is 1 if processing succeeded, 0 otherwise.
+   - Consumed metadata will be removed from the set of metadata available on the
-   Consumed metadata will be removed from the set of metadata available on the
+     call. consumed_md may be NULL if no metadata has been consumed.
-   call. */
+   - Response metadata will be set on the response. response_md may be NULL.
+   - status is GRPC_STATUS_OK for success or a specific status for an error.
+     Common error status for auth metadata processing is either
+     GRPC_STATUS_UNAUTHENTICATED in case of an authentication failure or
+     GRPC_STATUS PERMISSION_DENIED in case of an authorization failure.
+   - error_details gives details about the error. May be NULL. */
 typedef void (*grpc_process_auth_metadata_done_cb)(
     void *user_data, const grpc_metadata *consumed_md, size_t num_consumed_md,
-    int success);
+    const grpc_metadata *response_md, size_t num_response_md,
+    grpc_status_code status, const char *error_details);
 
 /* Pluggable server-side metadata processor object. */
 typedef struct {

src/core/channel/channel_args.c

@@ -37,6 +37,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
 
 #include <string.h>
 
@@ -146,3 +147,65 @@ grpc_channel_args *grpc_channel_args_set_compression_algorithm(
   tmp.value.integer = algorithm;
   return grpc_channel_args_copy_and_add(a, &tmp, 1);
 }
+
+/** Returns 1 if the argument for compression algorithm's enabled states bitset
+ * was found in \a a, returning the arg's value in \a states. Otherwise, returns
+ * 0. */
+static int find_compression_algorithm_states_bitset(
+    const grpc_channel_args *a, int **states_arg) {
+  if (a != NULL) {
+    size_t i;
+    for (i = 0; i < a->num_args; ++i) {
+      if (a->args[i].type == GRPC_ARG_INTEGER &&
+          !strcmp(GRPC_COMPRESSION_ALGORITHM_STATE_ARG, a->args[i].key)) {
+        *states_arg = &a->args[i].value.integer;
+        return 1; /* GPR_TRUE */
+      }
+    }
+  }
+  return 0; /* GPR_FALSE */
+}
+
+grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
+    grpc_channel_args **a,
+    grpc_compression_algorithm algorithm,
+    int state) {
+  int *states_arg;
+  grpc_channel_args *result = *a;
+  const int states_arg_found =
+      find_compression_algorithm_states_bitset(*a, &states_arg);
+
+  if (states_arg_found) {
+    if (state != 0) {
+      GPR_BITSET(states_arg, algorithm);
+    } else {
+      GPR_BITCLEAR(states_arg, algorithm);
+    }
+  } else {
+    /* create a new arg */
+    grpc_arg tmp;
+    tmp.type = GRPC_ARG_INTEGER;
+    tmp.key = GRPC_COMPRESSION_ALGORITHM_STATE_ARG;
+    /* all enabled by default */
+    tmp.value.integer = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
+    if (state != 0) {
+      GPR_BITSET(&tmp.value.integer, algorithm);
+    } else {
+      GPR_BITCLEAR(&tmp.value.integer, algorithm);
+    }
+    result = grpc_channel_args_copy_and_add(*a, &tmp, 1);
+    grpc_channel_args_destroy(*a);
+    *a = result;
+  }
+  return result;
+}
+
+int grpc_channel_args_compression_algorithm_get_states(
+    const grpc_channel_args *a) {
+  int *states_arg;
+  if (find_compression_algorithm_states_bitset(a, &states_arg)) {
+    return *states_arg;
+  } else {
+    return (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1; /* All algs. enabled */
+  }
+}

src/core/channel/channel_args.h

@@ -67,4 +67,24 @@ grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
 grpc_channel_args *grpc_channel_args_set_compression_algorithm(
     grpc_channel_args *a, grpc_compression_algorithm algorithm);
 
+/** Sets the support for the given compression algorithm. By default, all
+ * compression algorithms are enabled. It's an error to disable an algorithm set
+ * by grpc_channel_args_set_compression_algorithm.
+ *
+ * Returns an instance will the updated algorithm states. The \a a pointer is
+ * modified to point to the returned instance (which may be different from the
+ * input value of \a a). */
+grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
+    grpc_channel_args **a,
+    grpc_compression_algorithm algorithm,
+    int enabled);
+
+/** Returns the bitset representing the support state (true for enabled, false
+ * for disabled) for compression algorithms.
+ *
+ * The i-th bit of the returned bitset corresponds to the i-th entry in the
+ * grpc_compression_algorithm enum. */
+int grpc_channel_args_compression_algorithm_get_states(
+    const grpc_channel_args *a);
+
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_ARGS_H */

src/core/iomgr/pollset.h

@@ -74,10 +74,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset);
    grpc_pollset_work, and it is guaranteed that GRPC_POLLSET_MU(pollset) will
    not be released by grpc_pollset_work AFTER worker has been destroyed.
 
-   Returns true if some work has been done, and false if the deadline
+   Tries not to block past deadline. */
-   expired. */
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline);
-                      gpr_timespec deadline);
 
 /* Break one polling thread out of polling work for this pollset.
    If specific_worker is GRPC_POLLSET_KICK_BROADCAST, kick ALL the workers.

src/core/iomgr/pollset_multipoller_with_epoll.c

@@ -181,7 +181,7 @@ static void multipoll_with_epoll_pollset_maybe_work(
   pfds[1].events = POLLIN;
   pfds[1].revents = 0;
 
-  poll_rv = poll(pfds, 2, timeout_ms);
+  poll_rv = grpc_poll_function(pfds, 2, timeout_ms);
 
   if (poll_rv < 0) {
     if (errno != EINTR) {

src/core/iomgr/pollset_multipoller_with_poll_posix.c

@@ -144,7 +144,7 @@ static void multipoll_with_poll_pollset_maybe_work(
                                         POLLOUT, &watchers[i]);
   }
 
-  r = poll(pfds, pfd_count, timeout);
+  r = grpc_poll_function(pfds, pfd_count, timeout);
 
   for (i = 1; i < pfd_count; i++) {
     grpc_fd_end_poll(&watchers[i], pfds[i].revents & POLLIN,

src/core/iomgr/pollset_posix.c

@@ -38,7 +38,6 @@
 #include "src/core/iomgr/pollset_posix.h"
 
 #include <errno.h>
-#include <poll.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -57,6 +56,8 @@
 GPR_TLS_DECL(g_current_thread_poller);
 GPR_TLS_DECL(g_current_thread_worker);
 
+grpc_poll_function_type grpc_poll_function = poll;
+
 static void remove_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
   worker->prev->next = worker->next;
   worker->next->prev = worker->prev;
@@ -89,6 +90,7 @@ static void push_front_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {
+  /* pollset->mu already held */
   if (specific_worker != NULL) {
     if (specific_worker == GRPC_POLLSET_KICK_BROADCAST) {
       for (specific_worker = p->root_worker.next;
@@ -168,14 +170,10 @@ static void finish_shutdown(grpc_pollset *pollset) {
   pollset->shutdown_done_cb(pollset->shutdown_done_arg);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline) {
+                       gpr_timespec now, gpr_timespec deadline) {
   /* pollset->mu already held */
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   int added_worker = 0;
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0;
-  }
   /* this must happen before we (potentially) drop pollset->mu */
   worker->next = worker->prev = NULL;
   /* TODO(ctiller): pool these */
@@ -217,7 +215,6 @@ done:
       gpr_mu_lock(&pollset->mu);
     }
   }
-  return 1;
 }
 
 void grpc_pollset_shutdown(grpc_pollset *pollset,
@@ -456,7 +453,7 @@ static void basic_pollset_maybe_work(grpc_pollset *pollset,
 
   /* poll fd count (argument 2) is shortened by one if we have no events
      to poll on - such that it only includes the kicker */
-  r = poll(pfd, nfds, timeout);
+  r = grpc_poll_function(pfd, nfds, timeout);
   GRPC_TIMER_MARK(GRPC_PTAG_POLL_FINISHED, r);
 
   if (fd) {

src/core/iomgr/pollset_posix.h

@@ -34,6 +34,8 @@
 #ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 #define GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 
+#include <poll.h>
+
 #include <grpc/support/sync.h>
 #include "src/core/iomgr/wakeup_fd_posix.h"
 
@@ -118,4 +120,8 @@ void grpc_poll_become_multipoller(grpc_pollset *pollset, struct grpc_fd **fds,
  * be locked) */
 int grpc_pollset_has_workers(grpc_pollset *pollset);
 
+/* override to allow tests to hook poll() usage */
+typedef int (*grpc_poll_function_type)(struct pollfd *, nfds_t, int);
+extern grpc_poll_function_type grpc_poll_function;
+
 #endif /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H */

src/core/iomgr/pollset_windows.c

@@ -99,14 +99,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset) {
   gpr_mu_destroy(&pollset->mu);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker, 
-                      gpr_timespec deadline) {
+                       gpr_timespec now, gpr_timespec deadline) {
-  gpr_timespec now;
   int added_worker = 0;
-  now = gpr_now(GPR_CLOCK_MONOTONIC);
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0 /* GPR_FALSE */;
-  }
   worker->next = worker->prev = NULL;
   gpr_cv_init(&worker->cv);
   if (grpc_maybe_call_delayed_callbacks(&pollset->mu, 1 /* GPR_TRUE */)) {
@@ -127,7 +122,6 @@ done:
   if (added_worker) {
     remove_worker(pollset, worker);
   }
-  return 1 /* GPR_TRUE */;
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {

src/core/security/google_default_credentials.c

@@ -115,7 +115,7 @@ static int is_stack_running_on_compute_engine(void) {
   gpr_mu_lock(GRPC_POLLSET_MU(&detector.pollset));
   while (!detector.is_done) {
     grpc_pollset_worker worker;
-    grpc_pollset_work(&detector.pollset, &worker,
+    grpc_pollset_work(&detector.pollset, &worker, gpr_now(GPR_CLOCK_MONOTONIC),
                       gpr_inf_future(GPR_CLOCK_MONOTONIC));
   }
   gpr_mu_unlock(GRPC_POLLSET_MU(&detector.pollset));

src/core/security/server_auth_filter.c

@@ -104,24 +104,34 @@ static grpc_mdelem *remove_consumed_md(void *user_data, grpc_mdelem *md) {
   return md;
 }
 
-static void on_md_processing_done(void *user_data,
+static void on_md_processing_done(
-                                  const grpc_metadata *consumed_md,
+    void *user_data, const grpc_metadata *consumed_md, size_t num_consumed_md,
-                                  size_t num_consumed_md, int success) {
+    const grpc_metadata *response_md, size_t num_response_md,
+    grpc_status_code status, const char *error_details) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
 
-  if (success) {
+  /* TODO(jboeuf): Implement support for response_md. */
+  if (response_md != NULL && num_response_md > 0) {
+    gpr_log(GPR_INFO,
+            "response_md in auth metadata processing not supported for now. "
+            "Ignoring...");
+  }
+
+  if (status == GRPC_STATUS_OK) {
     calld->consumed_md = consumed_md;
     calld->num_consumed_md = num_consumed_md;
     grpc_metadata_batch_filter(&calld->md_op->data.metadata, remove_consumed_md,
                                elem);
-    calld->on_done_recv->cb(calld->on_done_recv->cb_arg, success);
+    calld->on_done_recv->cb(calld->on_done_recv->cb_arg, 1);
   } else {
-    gpr_slice message = gpr_slice_from_copied_string(
+    gpr_slice message;
-        "Authentication metadata processing failed.");
+    error_details = error_details != NULL
+                    ? error_details
+                    : "Authentication metadata processing failed.";
+    message = gpr_slice_from_copied_string(error_details);
     grpc_sopb_reset(calld->recv_ops);
-    grpc_transport_stream_op_add_close(&calld->transport_op,
+    grpc_transport_stream_op_add_close(&calld->transport_op, status, &message);
-                                       GRPC_STATUS_UNAUTHENTICATED, &message);
     grpc_call_next_op(elem, &calld->transport_op);
   }
 }

src/core/surface/completion_queue.c

@@ -170,6 +170,9 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
                                       gpr_timespec deadline, void *reserved) {
   grpc_event ret;
   grpc_pollset_worker worker;
+  int first_loop = 1;
+  gpr_timespec now;
+
   GPR_ASSERT(!reserved);
 
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
@@ -196,12 +199,15 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
       ret.type = GRPC_QUEUE_SHUTDOWN;
       break;
     }
-    if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
+    now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (!first_loop && gpr_time_cmp(now, deadline) >= 0) {
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
+    first_loop = 0;
+    grpc_pollset_work(&cc->pollset, &worker, now, deadline);
   }
   GRPC_SURFACE_TRACE_RETURNED_EVENT(cc, &ret);
   GRPC_CQ_INTERNAL_UNREF(cc, "next");
@@ -239,6 +245,9 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
   grpc_cq_completion *c;
   grpc_cq_completion *prev;
   grpc_pollset_worker worker;
+  gpr_timespec now;
+  int first_loop = 1;
+
   GPR_ASSERT(!reserved);
 
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
@@ -281,13 +290,16 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
-    if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
+    now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (!first_loop && gpr_time_cmp(now, deadline) >= 0) {
       del_plucker(cc, tag, &worker);
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
+    first_loop = 0;
+    grpc_pollset_work(&cc->pollset, &worker, now, deadline);
     del_plucker(cc, tag, &worker);
   }
 done:

src/cpp/server/create_default_thread_pool.cc

@@ -32,7 +32,7 @@
  */
 
 #include <grpc/support/cpu.h>
-#include <grpc++/dynamic_thread_pool.h>
+#include "src/cpp/server/dynamic_thread_pool.h"
 
 #ifndef GRPC_CUSTOM_DEFAULT_THREAD_POOL
 

src/cpp/server/dynamic_thread_pool.cc

@@ -33,7 +33,7 @@
 
 #include <grpc++/impl/sync.h>
 #include <grpc++/impl/thd.h>
-#include <grpc++/dynamic_thread_pool.h>
+#include "src/cpp/server/dynamic_thread_pool.h"
 
 namespace grpc {
 DynamicThreadPool::DynamicThread::DynamicThread(DynamicThreadPool* pool)

src/cpp/server/dynamic_thread_pool.h

@@ -31,19 +31,20 @@
  *
  */
 
-#ifndef GRPCXX_DYNAMIC_THREAD_POOL_H
+#ifndef GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
-#define GRPCXX_DYNAMIC_THREAD_POOL_H
+#define GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
 
 #include <grpc++/config.h>
 
 #include <grpc++/impl/sync.h>
 #include <grpc++/impl/thd.h>
-#include <grpc++/thread_pool_interface.h>
 
 #include <list>
 #include <memory>
 #include <queue>
 
+#include "src/cpp/server/thread_pool_interface.h"
+
 namespace grpc {
 
 class DynamicThreadPool GRPC_FINAL : public ThreadPoolInterface {
@@ -80,4 +81,4 @@ class DynamicThreadPool GRPC_FINAL : public ThreadPoolInterface {
 
 }  // namespace grpc
 
-#endif  // GRPCXX_DYNAMIC_THREAD_POOL_H
+#endif  // GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H

src/cpp/server/fixed_size_thread_pool.cc

@@ -33,7 +33,7 @@
 
 #include <grpc++/impl/sync.h>
 #include <grpc++/impl/thd.h>
-#include <grpc++/fixed_size_thread_pool.h>
+#include "src/cpp/server/fixed_size_thread_pool.h"
 
 namespace grpc {
 

src/cpp/server/fixed_size_thread_pool.h

@@ -31,18 +31,19 @@
  *
  */
 
-#ifndef GRPCXX_FIXED_SIZE_THREAD_POOL_H
+#ifndef GRPC_INTERNAL_CPP_FIXED_SIZE_THREAD_POOL_H
-#define GRPCXX_FIXED_SIZE_THREAD_POOL_H
+#define GRPC_INTERNAL_CPP_FIXED_SIZE_THREAD_POOL_H
 
 #include <grpc++/config.h>
 
 #include <grpc++/impl/sync.h>
 #include <grpc++/impl/thd.h>
-#include <grpc++/thread_pool_interface.h>
 
 #include <queue>
 #include <vector>
 
+#include "src/cpp/server/thread_pool_interface.h"
+
 namespace grpc {
 
 class FixedSizeThreadPool GRPC_FINAL : public ThreadPoolInterface {
@@ -64,4 +65,4 @@ class FixedSizeThreadPool GRPC_FINAL : public ThreadPoolInterface {
 
 }  // namespace grpc
 
-#endif  // GRPCXX_FIXED_SIZE_THREAD_POOL_H
+#endif  // GRPC_INTERNAL_CPP_FIXED_SIZE_THREAD_POOL_H

src/cpp/server/server.cc

@@ -43,13 +43,59 @@
 #include <grpc++/impl/service_type.h>
 #include <grpc++/server_context.h>
 #include <grpc++/server_credentials.h>
-#include <grpc++/thread_pool_interface.h>
 #include <grpc++/time.h>
 
 #include "src/core/profiling/timers.h"
+#include "src/cpp/server/thread_pool_interface.h"
 
 namespace grpc {
 
+class Server::UnimplementedAsyncRequestContext {
+ protected:
+  UnimplementedAsyncRequestContext() : generic_stream_(&server_context_) {}
+
+  GenericServerContext server_context_;
+  GenericServerAsyncReaderWriter generic_stream_;
+};
+
+class Server::UnimplementedAsyncRequest GRPC_FINAL
+    : public UnimplementedAsyncRequestContext,
+      public GenericAsyncRequest {
+ public:
+  UnimplementedAsyncRequest(Server* server, ServerCompletionQueue* cq)
+      : GenericAsyncRequest(server, &server_context_, &generic_stream_, cq, cq,
+                            NULL, false),
+        server_(server),
+        cq_(cq) {}
+
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
+
+  ServerContext* context() { return &server_context_; }
+  GenericServerAsyncReaderWriter* stream() { return &generic_stream_; }
+
+ private:
+  Server* const server_;
+  ServerCompletionQueue* const cq_;
+};
+
+typedef SneakyCallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus>
+    UnimplementedAsyncResponseOp;
+class Server::UnimplementedAsyncResponse GRPC_FINAL
+    : public UnimplementedAsyncResponseOp {
+ public:
+  UnimplementedAsyncResponse(UnimplementedAsyncRequest* request);
+  ~UnimplementedAsyncResponse() { delete request_; }
+
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
+    bool r = UnimplementedAsyncResponseOp::FinalizeResult(tag, status);
+    delete this;
+    return r;
+  }
+
+ private:
+  UnimplementedAsyncRequest* const request_;
+};
+
 class Server::ShutdownRequest GRPC_FINAL : public CompletionQueueTag {
  public:
   bool FinalizeResult(void** tag, bool* status) {
@@ -297,18 +343,23 @@ int Server::AddListeningPort(const grpc::string& addr,
   return creds->AddPortToServer(addr, server_);
 }
 
-bool Server::Start() {
+bool Server::Start(ServerCompletionQueue** cqs, size_t num_cqs) {
   GPR_ASSERT(!started_);
   started_ = true;
   grpc_server_start(server_);
 
   if (!has_generic_service_) {
-    unknown_method_.reset(new RpcServiceMethod(
+    if (!sync_methods_->empty()) {
-        "unknown", RpcMethod::BIDI_STREAMING, new UnknownMethodHandler));
+      unknown_method_.reset(new RpcServiceMethod(
-    // Use of emplace_back with just constructor arguments is not accepted here
+          "unknown", RpcMethod::BIDI_STREAMING, new UnknownMethodHandler));
-    // by gcc-4.4 because it can't match the anonymous nullptr with a proper
+      // Use of emplace_back with just constructor arguments is not accepted
-    // constructor implicitly. Construct the object and use push_back.
+      // here by gcc-4.4 because it can't match the anonymous nullptr with a 
-    sync_methods_->push_back(SyncRequest(unknown_method_.get(), nullptr));
+      // proper constructor implicitly. Construct the object and use push_back.
+      sync_methods_->push_back(SyncRequest(unknown_method_.get(), nullptr));
+    }
+    for (size_t i = 0; i < num_cqs; i++) {
+      new UnimplementedAsyncRequest(this, cqs[i]);
+    }
   }
   // Start processing rpcs.
   if (!sync_methods_->empty()) {
@@ -370,12 +421,14 @@ void Server::PerformOpsOnCall(CallOpSetInterface* ops, Call* call) {
 
 Server::BaseAsyncRequest::BaseAsyncRequest(
     Server* server, ServerContext* context,
-    ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag)
+    ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag,
+    bool delete_on_finalize)
     : server_(server),
       context_(context),
       stream_(stream),
       call_cq_(call_cq),
       tag_(tag),
+      delete_on_finalize_(delete_on_finalize),
       call_(nullptr) {
   memset(&initial_metadata_array_, 0, sizeof(initial_metadata_array_));
 }
@@ -402,14 +455,16 @@ bool Server::BaseAsyncRequest::FinalizeResult(void** tag, bool* status) {
   // just the pointers inside call are copied here
   stream_->BindCall(&call);
   *tag = tag_;
-  delete this;
+  if (delete_on_finalize_) {
+    delete this;
+  }
   return true;
 }
 
 Server::RegisteredAsyncRequest::RegisteredAsyncRequest(
     Server* server, ServerContext* context,
     ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag)
-    : BaseAsyncRequest(server, context, stream, call_cq, tag) {}
+    : BaseAsyncRequest(server, context, stream, call_cq, tag, true) {}
 
 void Server::RegisteredAsyncRequest::IssueRequest(
     void* registered_method, grpc_byte_buffer** payload,
@@ -423,8 +478,9 @@ void Server::RegisteredAsyncRequest::IssueRequest(
 Server::GenericAsyncRequest::GenericAsyncRequest(
     Server* server, GenericServerContext* context,
     ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
-    ServerCompletionQueue* notification_cq, void* tag)
+    ServerCompletionQueue* notification_cq, void* tag, bool delete_on_finalize)
-    : BaseAsyncRequest(server, context, stream, call_cq, tag) {
+    : BaseAsyncRequest(server, context, stream, call_cq, tag,
+                       delete_on_finalize) {
   grpc_call_details_init(&call_details_);
   GPR_ASSERT(notification_cq);
   GPR_ASSERT(call_cq);
@@ -445,6 +501,25 @@ bool Server::GenericAsyncRequest::FinalizeResult(void** tag, bool* status) {
   return BaseAsyncRequest::FinalizeResult(tag, status);
 }
 
+bool Server::UnimplementedAsyncRequest::FinalizeResult(void** tag,
+                                                       bool* status) {
+  if (GenericAsyncRequest::FinalizeResult(tag, status) && *status) {
+    new UnimplementedAsyncRequest(server_, cq_);
+    new UnimplementedAsyncResponse(this);
+  } else {
+    delete this;
+  }
+  return false;
+}
+
+Server::UnimplementedAsyncResponse::UnimplementedAsyncResponse(
+    UnimplementedAsyncRequest* request)
+    : request_(request) {
+  Status status(StatusCode::UNIMPLEMENTED, "");
+  UnknownMethodHandler::FillOps(request_->context(), this);
+  request_->stream()->call_.PerformOps(this);
+}
+
 void Server::ScheduleCallback() {
   {
     grpc::unique_lock<grpc::mutex> lock(mu_);

src/cpp/server/server_builder.cc

@@ -37,8 +37,8 @@
 #include <grpc/support/log.h>
 #include <grpc++/impl/service_type.h>
 #include <grpc++/server.h>
-#include <grpc++/thread_pool_interface.h>
+#include "src/cpp/server/thread_pool_interface.h"
-#include <grpc++/fixed_size_thread_pool.h>
+#include "src/cpp/server/fixed_size_thread_pool.h"
 
 namespace grpc {
 
@@ -89,10 +89,6 @@ void ServerBuilder::AddListeningPort(const grpc::string& addr,
   ports_.push_back(port);
 }
 
-void ServerBuilder::SetThreadPool(ThreadPoolInterface* thread_pool) {
-  thread_pool_ = thread_pool;
-}
-
 std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
   bool thread_pool_owned = false;
   if (!async_services_.empty() && !services_.empty()) {
@@ -103,12 +99,6 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
     thread_pool_ = CreateDefaultThreadPool();
     thread_pool_owned = true;
   }
-  // Async services only, create a thread pool to handle requests to unknown
-  // services.
-  if (!thread_pool_ && !generic_service_ && !async_services_.empty()) {
-    thread_pool_ = new FixedSizeThreadPool(1);
-    thread_pool_owned = true;
-  }
   std::unique_ptr<Server> server(
       new Server(thread_pool_, thread_pool_owned, max_message_size_));
   for (auto cq = cqs_.begin(); cq != cqs_.end(); ++cq) {
@@ -138,7 +128,7 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
       *port->selected_port = r;
     }
   }
-  if (!server->Start()) {
+  if (!server->Start(&cqs_[0], cqs_.size())) {
     return nullptr;
   }
   return server;

src/cpp/server/thread_pool_interface.h

@@ -31,8 +31,8 @@
  *
  */
 
-#ifndef GRPCXX_THREAD_POOL_INTERFACE_H
+#ifndef GRPC_INTERNAL_CPP_THREAD_POOL_INTERFACE_H
-#define GRPCXX_THREAD_POOL_INTERFACE_H
+#define GRPC_INTERNAL_CPP_THREAD_POOL_INTERFACE_H
 
 #include <functional>
 
@@ -51,4 +51,4 @@ ThreadPoolInterface* CreateDefaultThreadPool();
 
 }  // namespace grpc
 
-#endif  // GRPCXX_THREAD_POOL_INTERFACE_H
+#endif  // GRPC_INTERNAL_CPP_THREAD_POOL_INTERFACE_H

src/csharp/.gitignore

@@ -5,4 +5,5 @@ test-results
 packages
 Grpc.v12.suo
 TestResult.xml
+/TestResults
 *.nupkg

src/csharp/Grpc.Core.Tests/ChannelTest.cs

@@ -41,12 +41,6 @@ namespace Grpc.Core.Tests
 {
     public class ChannelTest
     {
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void Constructor_RejectsInvalidParams()
         {
@@ -56,36 +50,33 @@ namespace Grpc.Core.Tests
         [Test]
         public void State_IdleAfterCreation()
         {
-            using (var channel = new Channel("localhost", Credentials.Insecure))
+            var channel = new Channel("localhost", Credentials.Insecure);
-            {
+            Assert.AreEqual(ChannelState.Idle, channel.State);
-                Assert.AreEqual(ChannelState.Idle, channel.State);
+            channel.ShutdownAsync().Wait();
-            }
         }
 
         [Test]
         public void WaitForStateChangedAsync_InvalidArgument()
         {
-            using (var channel = new Channel("localhost", Credentials.Insecure))
+            var channel = new Channel("localhost", Credentials.Insecure);
-            {
+            Assert.Throws(typeof(ArgumentException), () => channel.WaitForStateChangedAsync(ChannelState.FatalFailure));
-                Assert.Throws(typeof(ArgumentException), () => channel.WaitForStateChangedAsync(ChannelState.FatalFailure));
+            channel.ShutdownAsync().Wait();
-            }
         }
 
         [Test]
         public void ResolvedTarget()
         {
-            using (var channel = new Channel("127.0.0.1", Credentials.Insecure))
+            var channel = new Channel("127.0.0.1", Credentials.Insecure);
-            {
+            Assert.IsTrue(channel.ResolvedTarget.Contains("127.0.0.1"));
-                Assert.IsTrue(channel.ResolvedTarget.Contains("127.0.0.1"));
+            channel.ShutdownAsync().Wait();
-            }
         }
 
         [Test]
-        public void Dispose_IsIdempotent()
+        public void Shutdown_AllowedOnlyOnce()
         {
             var channel = new Channel("localhost", Credentials.Insecure);
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
-            channel.Dispose();
+            Assert.Throws(typeof(InvalidOperationException), () => channel.ShutdownAsync().GetAwaiter().GetResult());
         }
     }
 }

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -63,16 +63,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public async Task UnaryCall()
         {
@@ -207,13 +201,6 @@ namespace Grpc.Core.Tests
             CollectionAssert.AreEqual(headers[1].ValueBytes, trailers[1].ValueBytes);
         }
 
-        [Test]
-        public void UnaryCall_DisposedChannel()
-        {
-            channel.Dispose();
-            Assert.Throws(typeof(ObjectDisposedException), () => Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "ABC"));
-        }
-
         [Test]
         public void UnaryCallPerformance()
         {

src/csharp/Grpc.Core.Tests/CompressionTest.cs

@@ -62,16 +62,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void WriteOptions_Unary()
         {

src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs

@@ -62,16 +62,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public async Task PropagateCancellation()
         {

src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj

@@ -64,6 +64,8 @@
       <Link>Version.cs</Link>
     </Compile>
     <Compile Include="ClientBaseTest.cs" />
+    <Compile Include="ShutdownTest.cs" />
+    <Compile Include="Internal\AsyncCallTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ClientServerTest.cs" />
     <Compile Include="ServerTest.cs" />

src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs

@@ -43,31 +43,40 @@ namespace Grpc.Core.Tests
         [Test]
         public void InitializeAndShutdownGrpcEnvironment()
         {
-            var env = GrpcEnvironment.GetInstance();
+            var env = GrpcEnvironment.AddRef();
             Assert.IsNotNull(env.CompletionQueue);
-            GrpcEnvironment.Shutdown();
+            GrpcEnvironment.Release();
         }
 
         [Test]
         public void SubsequentInvocations()
         {
-            var env1 = GrpcEnvironment.GetInstance();
+            var env1 = GrpcEnvironment.AddRef();
-            var env2 = GrpcEnvironment.GetInstance();
+            var env2 = GrpcEnvironment.AddRef();
-            Assert.IsTrue(object.ReferenceEquals(env1, env2));
+            Assert.AreSame(env1, env2);
-            GrpcEnvironment.Shutdown();
+            GrpcEnvironment.Release();
-            GrpcEnvironment.Shutdown();
+            GrpcEnvironment.Release();
         }
 
         [Test]
         public void InitializeAfterShutdown()
         {
-            var env1 = GrpcEnvironment.GetInstance();
+            Assert.AreEqual(0, GrpcEnvironment.GetRefCount());
-            GrpcEnvironment.Shutdown();
 
-            var env2 = GrpcEnvironment.GetInstance();
+            var env1 = GrpcEnvironment.AddRef();
-            GrpcEnvironment.Shutdown();
+            GrpcEnvironment.Release();
 
-            Assert.IsFalse(object.ReferenceEquals(env1, env2));
+            var env2 = GrpcEnvironment.AddRef();
+            GrpcEnvironment.Release();
+
+            Assert.AreNotSame(env1, env2);
+        }
+
+        [Test]
+        public void ReleaseWithoutAddRef()
+        {
+            Assert.AreEqual(0, GrpcEnvironment.GetRefCount());
+            Assert.Throws(typeof(InvalidOperationException), () => GrpcEnvironment.Release());
         }
 
         [Test]

src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs

@@ -0,0 +1,222 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+
+using Grpc.Core.Internal;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class AsyncCallTest
+    {
+        Channel channel;
+        FakeNativeCall fakeCall;
+        AsyncCall<string, string> asyncCall;
+
+        [SetUp]
+        public void Init()
+        {
+            channel = new Channel("localhost", Credentials.Insecure);
+
+            fakeCall = new FakeNativeCall();
+
+            var callDetails = new CallInvocationDetails<string, string>(channel, "someMethod", null, Marshallers.StringMarshaller, Marshallers.StringMarshaller, new CallOptions());
+            asyncCall = new AsyncCall<string, string>(callDetails, fakeCall);
+        }
+
+        [TearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+        }
+
+        [Test]
+        public void AsyncUnary_CompletionSuccess()
+        {
+            var resultTask = asyncCall.UnaryCallAsync("abc");
+            fakeCall.UnaryResponseClientHandler(true, new ClientSideStatus(Status.DefaultSuccess, new Metadata()), new byte[] { 1, 2, 3 }, new Metadata());
+            Assert.IsTrue(resultTask.IsCompleted);
+            Assert.IsTrue(fakeCall.IsDisposed);
+            Assert.AreEqual(Status.DefaultSuccess, asyncCall.GetStatus());
+        }
+
+        [Test]
+        public void AsyncUnary_CompletionFailure()
+        {
+            var resultTask = asyncCall.UnaryCallAsync("abc");
+            fakeCall.UnaryResponseClientHandler(false, new ClientSideStatus(new Status(StatusCode.Internal, ""), null), new byte[] { 1, 2, 3 }, new Metadata());
+
+            Assert.IsTrue(resultTask.IsCompleted);
+            Assert.IsTrue(fakeCall.IsDisposed);
+
+            Assert.AreEqual(StatusCode.Internal, asyncCall.GetStatus().StatusCode);
+            Assert.IsNull(asyncCall.GetTrailers());
+            var ex = Assert.Throws<RpcException>(() => resultTask.GetAwaiter().GetResult());
+            Assert.AreEqual(StatusCode.Internal, ex.Status.StatusCode);
+        }
+
+        internal class FakeNativeCall : INativeCall
+        {
+            public UnaryResponseClientHandler UnaryResponseClientHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedStatusOnClientHandler ReceivedStatusOnClientHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedMessageHandler ReceivedMessageHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedResponseHeadersHandler ReceivedResponseHeadersHandler
+            {
+                get;
+                set;
+            }
+
+            public SendCompletionHandler SendCompletionHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedCloseOnServerHandler ReceivedCloseOnServerHandler
+            {
+                get;
+                set;
+            }
+
+            public bool IsCancelled
+            {
+                get;
+                set;
+            }
+
+            public bool IsDisposed
+            {
+                get;
+                set;
+            }
+
+            public void Cancel()
+            {
+                IsCancelled = true;
+            }
+
+            public void CancelWithStatus(Status status)
+            {
+                IsCancelled = true;
+            }
+
+            public string GetPeer()
+            {
+                return "PEER";
+            }
+
+            public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                UnaryResponseClientHandler = callback;
+            }
+
+            public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                UnaryResponseClientHandler = callback;
+            }
+
+            public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                ReceivedStatusOnClientHandler = callback;
+            }
+
+            public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                ReceivedStatusOnClientHandler = callback;
+            }
+
+            public void StartReceiveMessage(ReceivedMessageHandler callback)
+            {
+                ReceivedMessageHandler = callback;
+            }
+
+            public void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback)
+            {
+                ReceivedResponseHeadersHandler = callback;
+            }
+
+            public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendCloseFromClient(SendCompletionHandler callback)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartServerSide(ReceivedCloseOnServerHandler callback)
+            {
+                ReceivedCloseOnServerHandler = callback;
+            }
+
+            public void Dispose()
+            {
+                IsDisposed = true;
+            }
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/ResponseHeadersTest.cs

@@ -32,13 +32,16 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+
 using Grpc.Core;
 using Grpc.Core.Internal;
 using Grpc.Core.Utils;
+
 using NUnit.Framework;
 
 namespace Grpc.Core.Tests
@@ -69,14 +72,82 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
+        [Test]
-        public void CleanupClass()
+        public async Task ResponseHeadersAsync_UnaryCall()
+        {
+            helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                return "PASS";
+            });
+
+            var call = Calls.AsyncUnaryCall(helper.CreateUnaryCall(), "");
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual(headers.Count, responseHeaders.Count);
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            Assert.AreEqual("abcdefg", responseHeaders[0].Value);
+
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_ClientStreamingCall()
+        {
+            helper.ClientStreamingHandler = new ClientStreamingServerMethod<string, string>(async (requestStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                return "PASS";
+            });
+
+            var call = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall());
+            await call.RequestStream.CompleteAsync();
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_ServerStreamingCall()
+        {
+            helper.ServerStreamingHandler = new ServerStreamingServerMethod<string, string>(async (request, responseStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                await responseStream.WriteAsync("PASS");
+            });
+
+            var call = Calls.AsyncServerStreamingCall(helper.CreateServerStreamingCall(), "");
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            CollectionAssert.AreEqual(new[] { "PASS" }, await call.ResponseStream.ToListAsync());
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_DuplexStreamingCall()
         {
-            GrpcEnvironment.Shutdown();
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                while (await requestStream.MoveNext())
+                {
+                    await responseStream.WriteAsync(requestStream.Current);
+                }
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall());
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            var messages = new[] { "PASS" };
+            await call.RequestStream.WriteAllAsync(messages);
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            CollectionAssert.AreEqual(messages, await call.ResponseStream.ToListAsync());
         }
 
         [Test]

src/csharp/Grpc.Core.Tests/ServerTest.cs

@@ -51,7 +51,6 @@ namespace Grpc.Core.Tests
             };
             server.Start();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -67,8 +66,7 @@ namespace Grpc.Core.Tests
             Assert.Greater(boundPort.BoundPort, 0);
 
             server.Start();
-            server.ShutdownAsync();
+            server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -83,7 +81,6 @@ namespace Grpc.Core.Tests
             Assert.Throws(typeof(InvalidOperationException), () => server.Services.Add(ServerServiceDefinition.CreateBuilder("serviceName").Build()));
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
     }
 }

src/csharp/Grpc.Core.Tests/ShutdownTest.cs

@@ -0,0 +1,77 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class ShutdownTest
+    {
+        const string Host = "127.0.0.1";
+
+        MockServiceHelper helper;
+        Server server;
+        Channel channel;
+
+        [SetUp]
+        public void Init()
+        {
+            helper = new MockServiceHelper(Host);
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+        }
+
+        [Test]
+        public async Task AbandonedCall()
+        {
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                await requestStream.ToListAsync();
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall(new CallOptions(deadline: DateTime.UtcNow.AddMilliseconds(1))));
+
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/TimeoutsTest.cs

@@ -65,16 +65,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void InfiniteDeadline()
         {

src/csharp/Grpc.Core/AsyncClientStreamingCall.cs

@@ -44,14 +44,16 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly Task<TResponse> responseAsync;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseAsync = responseAsync;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -68,6 +70,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Async stream to send streaming requests.
         /// </summary>

src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs

@@ -32,6 +32,7 @@
 #endregion
 
 using System;
+using System.Threading.Tasks;
 
 namespace Grpc.Core
 {
@@ -42,14 +43,16 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseStream = responseStream;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -77,6 +80,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Gets the call status if the call has already finished.
         /// Throws InvalidOperationException otherwise.

src/csharp/Grpc.Core/AsyncServerStreamingCall.cs

@@ -32,6 +32,7 @@
 #endregion
 
 using System;
+using System.Threading.Tasks;
 
 namespace Grpc.Core
 {
@@ -41,13 +42,15 @@ namespace Grpc.Core
     public sealed class AsyncServerStreamingCall<TResponse> : IDisposable
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseStream = responseStream;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -64,6 +67,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Gets the call status if the call has already finished.
         /// Throws InvalidOperationException otherwise.

src/csharp/Grpc.Core/AsyncUnaryCall.cs

@@ -43,13 +43,15 @@ namespace Grpc.Core
     public sealed class AsyncUnaryCall<TResponse> : IDisposable
     {
         readonly Task<TResponse> responseAsync;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncUnaryCall(Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncUnaryCall(Task<TResponse> responseAsync, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseAsync = responseAsync;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -66,6 +68,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Allows awaiting this object directly.
         /// </summary>

src/csharp/Grpc.Core/Calls.cs

@@ -74,7 +74,7 @@ namespace Grpc.Core
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             var asyncResult = asyncCall.UnaryCallAsync(req);
-            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -93,7 +93,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             asyncCall.StartServerStreamingCall(req);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -110,7 +110,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             var resultTask = asyncCall.ClientStreamingCallAsync();
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
-            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -130,7 +130,7 @@ namespace Grpc.Core
             asyncCall.StartDuplexStreamingCall();
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
     }
 }

src/csharp/Grpc.Core/Channel.cs

@@ -45,15 +45,19 @@ namespace Grpc.Core
     /// <summary>
     /// gRPC Channel
     /// </summary>
-    public class Channel : IDisposable
+    public class Channel
     {
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Channel>();
 
+        readonly object myLock = new object();
+        readonly AtomicCounter activeCallCounter = new AtomicCounter();
+
         readonly string target;
         readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
         readonly List<ChannelOption> options;
-        bool disposed;
+
+        bool shutdownRequested;
 
         /// <summary>
         /// Creates a channel that connects to a specific host.
@@ -65,7 +69,7 @@ namespace Grpc.Core
         public Channel(string target, Credentials credentials, IEnumerable<ChannelOption> options = null)
         {
             this.target = Preconditions.CheckNotNull(target, "target");
-            this.environment = GrpcEnvironment.GetInstance();
+            this.environment = GrpcEnvironment.AddRef();
             this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
 
             EnsureUserAgentChannelOption(this.options);
@@ -172,12 +176,26 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Destroys the underlying channel.
+        /// Waits until there are no more active calls for this channel and then cleans up
+        /// resources used by this channel.
         /// </summary>
-        public void Dispose()
+        public async Task ShutdownAsync()
         {
-            Dispose(true);
+            lock (myLock)
-            GC.SuppressFinalize(this);
+            {
+                Preconditions.CheckState(!shutdownRequested);
+                shutdownRequested = true;
+            }
+
+            var activeCallCount = activeCallCounter.Count;
+            if (activeCallCount > 0)
+            {
+                Logger.Warning("Channel shutdown was called but there are still {0} active calls for that channel.", activeCallCount);
+            }
+
+            handle.Dispose();
+
+            await Task.Run(() => GrpcEnvironment.Release());
         }
 
         internal ChannelSafeHandle Handle
@@ -196,13 +214,20 @@ namespace Grpc.Core
             }
         }
 
-        protected virtual void Dispose(bool disposing)
+        internal void AddCallReference(object call)
         {
-            if (disposing && handle != null && !disposed)
+            activeCallCounter.Increment();
-            {
+
-                disposed = true;
+            bool success = false;
-                handle.Dispose();
+            handle.DangerousAddRef(ref success);
-            }
+            Preconditions.CheckState(success);
+        }
+
+        internal void RemoveCallReference(object call)
+        {
+            handle.DangerousRelease();
+
+            activeCallCounter.Decrement();
         }
 
         private static void EnsureUserAgentChannelOption(List<ChannelOption> options)

src/csharp/Grpc.Core/Grpc.Core.csproj

@@ -49,6 +49,7 @@
     <Compile Include="AsyncDuplexStreamingCall.cs" />
     <Compile Include="AsyncServerStreamingCall.cs" />
     <Compile Include="IClientStreamWriter.cs" />
+    <Compile Include="Internal\INativeCall.cs" />
     <Compile Include="IServerStreamWriter.cs" />
     <Compile Include="IAsyncStreamWriter.cs" />
     <Compile Include="IAsyncStreamReader.cs" />

src/csharp/Grpc.Core/GrpcEnvironment.cs

@@ -58,6 +58,7 @@ namespace Grpc.Core
 
         static object staticLock = new object();
         static GrpcEnvironment instance;
+        static int refCount;
 
         static ILogger logger = new ConsoleLogger();
 
@@ -67,13 +68,14 @@ namespace Grpc.Core
         bool isClosed;
 
         /// <summary>
-        /// Returns an instance of initialized gRPC environment.
+        /// Returns a reference-counted instance of initialized gRPC environment.
-        /// Subsequent invocations return the same instance unless Shutdown has been called first.
+        /// Subsequent invocations return the same instance unless reference count has dropped to zero previously.
         /// </summary>
-        internal static GrpcEnvironment GetInstance()
+        internal static GrpcEnvironment AddRef()
         {
             lock (staticLock)
             {
+                refCount++;
                 if (instance == null)
                 {
                     instance = new GrpcEnvironment();
@@ -83,14 +85,16 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Shuts down the gRPC environment if it was initialized before.
+        /// Decrements the reference count for currently active environment and shuts down the gRPC environment if reference count drops to zero.
-        /// Blocks until the environment has been fully shutdown.
+        /// (and blocks until the environment has been fully shutdown).
         /// </summary>
-        public static void Shutdown()
+        internal static void Release()
         {
             lock (staticLock)
             {
-                if (instance != null)
+                Preconditions.CheckState(refCount > 0);
+                refCount--;
+                if (refCount == 0)
                 {
                     instance.Close();
                     instance = null;
@@ -98,6 +102,14 @@ namespace Grpc.Core
             }
         }
 
+        internal static int GetRefCount()
+        {
+            lock (staticLock)
+            {
+                return refCount;
+            }
+        }
+
         /// <summary>
         /// Gets application-wide logger used by gRPC.
         /// </summary>
@@ -125,12 +137,10 @@ namespace Grpc.Core
         private GrpcEnvironment()
         {
             NativeLogRedirector.Redirect();
-            grpcsharp_init();
+            GrpcNativeInit();
             completionRegistry = new CompletionRegistry(this);
             threadPool = new GrpcThreadPool(this, THREAD_POOL_SIZE);
             threadPool.Start();
-            // TODO: use proper logging here
-            Logger.Info("gRPC initialized.");
         }
 
         /// <summary>
@@ -175,6 +185,16 @@ namespace Grpc.Core
             return Marshal.PtrToStringAnsi(ptr);
         }
 
+        internal static void GrpcNativeInit()
+        {
+            grpcsharp_init();
+        }
+
+        internal static void GrpcNativeShutdown()
+        {
+            grpcsharp_shutdown();
+        }
+
         /// <summary>
         /// Shuts down this environment.
         /// </summary>
@@ -185,12 +205,10 @@ namespace Grpc.Core
                 throw new InvalidOperationException("Close has already been called");
             }
             threadPool.Stop();
-            grpcsharp_shutdown();
+            GrpcNativeShutdown();
             isClosed = true;
 
             debugStats.CheckOK();
-
-            Logger.Info("gRPC shutdown.");
         }
     }
 }

src/csharp/Grpc.Core/Internal/AsyncCall.cs

@@ -51,22 +51,35 @@ namespace Grpc.Core.Internal
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<AsyncCall<TRequest, TResponse>>();
 
         readonly CallInvocationDetails<TRequest, TResponse> details;
+        readonly INativeCall injectedNativeCall;  // for testing
 
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
+        // Indicates that steaming call has finished.
+        TaskCompletionSource<object> streamingCallFinishedTcs = new TaskCompletionSource<object>();
+
+        // Response headers set here once received.
+        TaskCompletionSource<Metadata> responseHeadersTcs = new TaskCompletionSource<Metadata>();
+
         // Set after status is received. Used for both unary and streaming response calls.
         ClientSideStatus? finishedStatus;
 
-        bool readObserverCompleted;  // True if readObserver has already been completed.
-
         public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails)
-            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer)
+            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer, callDetails.Channel.Environment)
         {
             this.details = callDetails.WithOptions(callDetails.Options.Normalize());
             this.initialMetadataSent = true;  // we always send metadata at the very beginning of the call.
         }
 
+        /// <summary>
+        /// This constructor should only be used for testing.
+        /// </summary>
+        public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails, INativeCall injectedNativeCall) : this(callDetails)
+        {
+            this.injectedNativeCall = injectedNativeCall;
+        }
+
         // TODO: this method is not Async, so it shouldn't be in AsyncCall class, but 
         // it is reusing fair amount of code in this class, so we are leaving it here.
         /// <summary>
@@ -100,7 +113,7 @@ namespace Grpc.Core.Internal
                         bool success = (ev.success != 0);
                         try
                         {
-                            HandleUnaryResponse(success, ctx);
+                            HandleUnaryResponse(success, ctx.GetReceivedStatusOnClient(), ctx.GetReceivedMessage(), ctx.GetReceivedInitialMetadata());
                         }
                         catch (Exception e)
                         {
@@ -125,7 +138,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 halfcloseRequested = true;
                 readingDone = true;
@@ -152,7 +165,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 readingDone = true;
 
@@ -176,10 +189,9 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 halfcloseRequested = true;
-                halfclosed = true;  // halfclose not confirmed yet, but it will be once finishedHandler is called.
 
                 byte[] payload = UnsafeSerialize(msg);
 
@@ -187,6 +199,7 @@ namespace Grpc.Core.Internal
                 {
                     call.StartServerStreaming(HandleFinished, payload, metadataArray, GetWriteFlagsForCall());
                 }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
         }
 
@@ -201,12 +214,13 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
                     call.StartDuplexStreaming(HandleFinished, metadataArray);
                 }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
         }
 
@@ -247,6 +261,28 @@ namespace Grpc.Core.Internal
             }
         }
 
+        /// <summary>
+        /// Get the task that completes once if streaming call finishes with ok status and throws RpcException with given status otherwise.
+        /// </summary>
+        public Task StreamingCallFinishedTask
+        {
+            get
+            {
+                return streamingCallFinishedTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Get the task that completes once response headers are received.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return responseHeadersTcs.Task;
+            }
+        }
+
         /// <summary>
         /// Gets the resulting status if the call has already finished.
         /// Throws InvalidOperationException otherwise.
@@ -281,51 +317,31 @@ namespace Grpc.Core.Internal
             }
         }
 
-        /// <summary>
+        protected override void OnAfterReleaseResources()
-        /// On client-side, we only fire readCompletionDelegate once all messages have been read 
-        /// and status has been received.
-        /// </summary>
-        protected override void ProcessLastRead(AsyncCompletionDelegate<TResponse> completionDelegate)
         {
-            if (completionDelegate != null && readingDone && finishedStatus.HasValue)
+            details.Channel.RemoveCallReference(this);
-            {
-                bool shouldComplete;
-                lock (myLock)
-                {
-                    shouldComplete = !readObserverCompleted;
-                    readObserverCompleted = true;
-                }
-
-                if (shouldComplete)
-                {
-                    var status = finishedStatus.Value.Status;
-                    if (status.StatusCode != StatusCode.OK)
-                    {
-                        FireCompletion(completionDelegate, default(TResponse), new RpcException(status));
-                    }
-                    else
-                    {
-                        FireCompletion(completionDelegate, default(TResponse), null);
-                    }
-                }
-            }
         }
 
-        protected override void OnReleaseResources()
+        private void Initialize(CompletionQueueSafeHandle cq)
         {
-            details.Channel.Environment.DebugStats.ActiveClientCalls.Decrement();
+            var call = CreateNativeCall(cq);
+            details.Channel.AddCallReference(this);
+            InitializeInternal(call);
+            RegisterCancellationCallback();
         }
 
-        private void Initialize(CompletionQueueSafeHandle cq)
+        private INativeCall CreateNativeCall(CompletionQueueSafeHandle cq)
         {
+            if (injectedNativeCall != null)
+            {
+                return injectedNativeCall;  // allows injecting a mock INativeCall in tests.
+            }
+
             var parentCall = details.Options.PropagationToken != null ? details.Options.PropagationToken.ParentCall : CallSafeHandle.NullInstance;
 
-            var call = details.Channel.Handle.CreateCall(details.Channel.Environment.CompletionRegistry,
+            return details.Channel.Handle.CreateCall(environment.CompletionRegistry,
                 parentCall, ContextPropagationToken.DefaultMask, cq,
                 details.Method, details.Host, Timespec.FromDateTime(details.Options.Deadline.Value));
-            details.Channel.Environment.DebugStats.ActiveClientCalls.Increment();
-            InitializeInternal(call);
-            RegisterCancellationCallback();
         }
 
         // Make sure that once cancellationToken for this call is cancelled, Cancel() will be called.
@@ -348,31 +364,31 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
-        /// Handler for unary response completion.
+        /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleUnaryResponse(bool success, BatchContextSafeHandle ctx)
+        private void HandleReceivedResponseHeaders(bool success, Metadata responseHeaders)
         {
-            var fullStatus = ctx.GetReceivedStatusOnClient();
+            responseHeadersTcs.SetResult(responseHeaders);
+        }
 
+        /// <summary>
+        /// Handler for unary response completion.
+        /// </summary>
+        private void HandleUnaryResponse(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders)
+        {
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = fullStatus;
+                finishedStatus = receivedStatus;
-
-                halfclosed = true;
 
                 ReleaseResourcesIfPossible();
             }
 
-            if (!success)
+            responseHeadersTcs.SetResult(responseHeaders);
-            {
-                unaryResponseTcs.SetException(new RpcException(new Status(StatusCode.Internal, "Internal error occured.")));
-                return;
-            }
 
-            var status = fullStatus.Status;
+            var status = receivedStatus.Status;
 
-            if (status.StatusCode != StatusCode.OK)
+            if (!success || status.StatusCode != StatusCode.OK)
             {
                 unaryResponseTcs.SetException(new RpcException(status));
                 return;
@@ -380,7 +396,7 @@ namespace Grpc.Core.Internal
 
             // TODO: handle deserialization error
             TResponse msg;
-            TryDeserialize(ctx.GetReceivedMessage(), out msg);
+            TryDeserialize(receivedMessage, out msg);
 
             unaryResponseTcs.SetResult(msg);
         }
@@ -388,22 +404,25 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleFinished(bool success, BatchContextSafeHandle ctx)
+        private void HandleFinished(bool success, ClientSideStatus receivedStatus)
         {
-            var fullStatus = ctx.GetReceivedStatusOnClient();
-
-            AsyncCompletionDelegate<TResponse> origReadCompletionDelegate = null;
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = fullStatus;
+                finishedStatus = receivedStatus;
-
-                origReadCompletionDelegate = readCompletionDelegate;
 
                 ReleaseResourcesIfPossible();
             }
 
-            ProcessLastRead(origReadCompletionDelegate);
+            var status = receivedStatus.Status;
+
+            if (!success || status.StatusCode != StatusCode.OK)
+            {
+                streamingCallFinishedTcs.SetException(new RpcException(status));
+                return;
+            }
+
+            streamingCallFinishedTcs.SetResult(null);
         }
     }
 }

src/csharp/Grpc.Core/Internal/AsyncCallBase.cs

@@ -54,30 +54,30 @@ namespace Grpc.Core.Internal
         readonly Func<TWrite, byte[]> serializer;
         readonly Func<byte[], TRead> deserializer;
 
+        protected readonly GrpcEnvironment environment;
         protected readonly object myLock = new object();
 
-        protected CallSafeHandle call;
+        protected INativeCall call;
         protected bool disposed;
 
         protected bool started;
-        protected bool errorOccured;
         protected bool cancelRequested;
 
         protected AsyncCompletionDelegate<object> sendCompletionDelegate;  // Completion of a pending send or sendclose if not null.
         protected AsyncCompletionDelegate<TRead> readCompletionDelegate;  // Completion of a pending send or sendclose if not null.
 
-        protected bool readingDone;
+        protected bool readingDone;  // True if last read (i.e. read with null payload) was already received.
-        protected bool halfcloseRequested;
+        protected bool halfcloseRequested;  // True if send close have been initiated.
-        protected bool halfclosed;
         protected bool finished;  // True if close has been received from the peer.
 
         protected bool initialMetadataSent;
-        protected long streamingWritesCounter;
+        protected long streamingWritesCounter;  // Number of streaming send operations started so far.
 
-        public AsyncCallBase(Func<TWrite, byte[]> serializer, Func<byte[], TRead> deserializer)
+        public AsyncCallBase(Func<TWrite, byte[]> serializer, Func<byte[], TRead> deserializer, GrpcEnvironment environment)
         {
             this.serializer = Preconditions.CheckNotNull(serializer);
             this.deserializer = Preconditions.CheckNotNull(deserializer);
+            this.environment = Preconditions.CheckNotNull(environment);
         }
 
         /// <summary>
@@ -114,7 +114,7 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected void InitializeInternal(CallSafeHandle call)
+        protected void InitializeInternal(INativeCall call)
         {
             lock (myLock)
             {
@@ -159,16 +159,6 @@ namespace Grpc.Core.Internal
             }
         }
 
-        // TODO(jtattermusch): find more fitting name for this method.
-        /// <summary>
-        /// Default behavior just completes the read observer, but more sofisticated behavior might be required
-        /// by subclasses.
-        /// </summary>
-        protected virtual void ProcessLastRead(AsyncCompletionDelegate<TRead> completionDelegate)
-        {
-            FireCompletion(completionDelegate, default(TRead), null);
-        }
-
         /// <summary>
         /// If there are no more pending actions and no new actions can be started, releases
         /// the underlying native resources.
@@ -177,7 +167,7 @@ namespace Grpc.Core.Internal
         {
             if (!disposed && call != null)
             {
-                bool noMoreSendCompletions = halfclosed || (cancelRequested && sendCompletionDelegate == null);
+                bool noMoreSendCompletions = sendCompletionDelegate == null && (halfcloseRequested || cancelRequested || finished);
                 if (noMoreSendCompletions && readingDone && finished)
                 {
                     ReleaseResources();
@@ -189,34 +179,33 @@ namespace Grpc.Core.Internal
 
         private void ReleaseResources()
         {
-            OnReleaseResources();
             if (call != null)
             {
                 call.Dispose();
             }
             disposed = true;
+            OnAfterReleaseResources();
         }
 
-        protected virtual void OnReleaseResources()
+        protected virtual void OnAfterReleaseResources()
         {
         }
 
         protected void CheckSendingAllowed()
         {
             Preconditions.CheckState(started);
-            Preconditions.CheckState(!errorOccured);
             CheckNotCancelled();
             Preconditions.CheckState(!disposed);
 
             Preconditions.CheckState(!halfcloseRequested, "Already halfclosed.");
+            Preconditions.CheckState(!finished, "Already finished.");
             Preconditions.CheckState(sendCompletionDelegate == null, "Only one write can be pending at a time");
         }
 
-        protected void CheckReadingAllowed()
+        protected virtual void CheckReadingAllowed()
         {
             Preconditions.CheckState(started);
             Preconditions.CheckState(!disposed);
-            Preconditions.CheckState(!errorOccured);
 
             Preconditions.CheckState(!readingDone, "Stream has already been closed.");
             Preconditions.CheckState(readCompletionDelegate == null, "Only one read can be pending at a time");
@@ -280,7 +269,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles send completion.
         /// </summary>
-        protected void HandleSendFinished(bool success, BatchContextSafeHandle ctx)
+        protected void HandleSendFinished(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
@@ -304,12 +293,11 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles halfclose completion.
         /// </summary>
-        protected void HandleHalfclosed(bool success, BatchContextSafeHandle ctx)
+        protected void HandleHalfclosed(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
             {
-                halfclosed = true;
                 origCompletionDelegate = sendCompletionDelegate;
                 sendCompletionDelegate = null;
 
@@ -329,23 +317,17 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles streaming read completion.
         /// </summary>
-        protected void HandleReadFinished(bool success, BatchContextSafeHandle ctx)
+        protected void HandleReadFinished(bool success, byte[] receivedMessage)
         {
-            var payload = ctx.GetReceivedMessage();
-
             AsyncCompletionDelegate<TRead> origCompletionDelegate = null;
             lock (myLock)
             {
                 origCompletionDelegate = readCompletionDelegate;
-                if (payload != null)
+                readCompletionDelegate = null;
-                {
+
-                    readCompletionDelegate = null;
+                if (receivedMessage == null)
-                }
-                else
                 {
-                    // This was the last read. Keeping the readCompletionDelegate
+                    // This was the last read.
-                    // to be either fired by this handler or by client-side finished
-                    // handler.
                     readingDone = true;
                 }
 
@@ -354,17 +336,17 @@ namespace Grpc.Core.Internal
 
             // TODO: handle the case when error occured...
 
-            if (payload != null)
+            if (receivedMessage != null)
             {
                 // TODO: handle deserialization error
                 TRead msg;
-                TryDeserialize(payload, out msg);
+                TryDeserialize(receivedMessage, out msg);
 
                 FireCompletion(origCompletionDelegate, msg, null);
             }
             else
             {
-                ProcessLastRead(origCompletionDelegate);
+                FireCompletion(origCompletionDelegate, default(TRead), null);
             }
         }
     }

src/csharp/Grpc.Core/Internal/AsyncCallServer.cs

@@ -49,17 +49,18 @@ namespace Grpc.Core.Internal
     {
         readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
         readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
-        readonly GrpcEnvironment environment;
+        readonly Server server;
 
-        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment) : base(serializer, deserializer)
+        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment, Server server) : base(serializer, deserializer, environment)
         {
-            this.environment = Preconditions.CheckNotNull(environment);
+            this.server = Preconditions.CheckNotNull(server);
         }
 
         public void Initialize(CallSafeHandle call)
         {
             call.SetCompletionRegistry(environment.CompletionRegistry);
-            environment.DebugStats.ActiveServerCalls.Increment();
+
+            server.AddCallReference(this);
             InitializeInternal(call);
         }
 
@@ -168,18 +169,22 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected override void OnReleaseResources()
+        protected override void CheckReadingAllowed()
         {
-            environment.DebugStats.ActiveServerCalls.Decrement();
+            base.CheckReadingAllowed();
+            Preconditions.CheckArgument(!cancelRequested);
+        }
+
+        protected override void OnAfterReleaseResources()
+        {
+            server.RemoveCallReference(this);
         }
 
         /// <summary>
         /// Handles the server side close completion.
         /// </summary>
-        private void HandleFinishedServerside(bool success, BatchContextSafeHandle ctx)
+        private void HandleFinishedServerside(bool success, bool cancelled)
         {
-            bool cancelled = ctx.GetReceivedCloseOnServerCancelled();
-
             lock (myLock)
             {
                 finished = true;

src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs

@@ -134,7 +134,7 @@ namespace Grpc.Core.Internal
         }
 
         // Gets data of server_rpc_new completion.
-        public ServerRpcNew GetServerRpcNew()
+        public ServerRpcNew GetServerRpcNew(Server server)
         {
             var call = grpcsharp_batch_context_server_rpc_new_call(this);
 
@@ -145,7 +145,7 @@ namespace Grpc.Core.Internal
             IntPtr metadataArrayPtr = grpcsharp_batch_context_server_rpc_new_request_metadata(this);
             var metadata = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);
 
-            return new ServerRpcNew(call, method, host, deadline, metadata);
+            return new ServerRpcNew(server, call, method, host, deadline, metadata);
         }
 
         // Gets data of receive_close_on_server completion.
@@ -198,14 +198,16 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal struct ServerRpcNew
     {
+        readonly Server server;
         readonly CallSafeHandle call;
         readonly string method;
         readonly string host;
         readonly Timespec deadline;
         readonly Metadata requestMetadata;
 
-        public ServerRpcNew(CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
+        public ServerRpcNew(Server server, CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
         {
+            this.server = server;
             this.call = call;
             this.method = method;
             this.host = host;
@@ -213,6 +215,14 @@ namespace Grpc.Core.Internal
             this.requestMetadata = requestMetadata;
         }
 
+        public Server Server
+        {
+            get
+            {
+                return this.server;
+            }
+        }
+
         public CallSafeHandle Call
         {
             get

src/csharp/Grpc.Core/Internal/CallSafeHandle.cs

@@ -40,7 +40,7 @@ namespace Grpc.Core.Internal
     /// <summary>
     /// grpc_call from <grpc/grpc.h>
     /// </summary>
-    internal class CallSafeHandle : SafeHandleZeroIsInvalid
+    internal class CallSafeHandle : SafeHandleZeroIsInvalid, INativeCall
     {
         public static readonly CallSafeHandle NullInstance = new CallSafeHandle();
 
@@ -86,6 +86,10 @@ namespace Grpc.Core.Internal
         static extern GRPCCallError grpcsharp_call_recv_message(CallSafeHandle call,
             BatchContextSafeHandle ctx);
 
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern GRPCCallError grpcsharp_call_recv_initial_metadata(CallSafeHandle call,
+            BatchContextSafeHandle ctx);
+
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_serverside(CallSafeHandle call,
             BatchContextSafeHandle ctx);
@@ -109,10 +113,10 @@ namespace Grpc.Core.Internal
             this.completionRegistry = completionRegistry;
         }
 
-        public void StartUnary(BatchCompletionDelegate callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
             grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags)
                 .CheckOk();
         }
@@ -123,66 +127,73 @@ namespace Grpc.Core.Internal
                 .CheckOk();
         }
 
-        public void StartClientStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
             grpcsharp_call_start_client_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartServerStreaming(BatchCompletionDelegate callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
             grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags).CheckOk();
         }
 
-        public void StartDuplexStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
             grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartSendMessage(BatchCompletionDelegate callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
+        public void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_message(this, ctx, payload, new UIntPtr((ulong)payload.Length), writeFlags, sendEmptyInitialMetadata).CheckOk();
         }
 
-        public void StartSendCloseFromClient(BatchCompletionDelegate callback)
+        public void StartSendCloseFromClient(SendCompletionHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_close_from_client(this, ctx).CheckOk();
         }
 
-        public void StartSendStatusFromServer(BatchCompletionDelegate callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata).CheckOk();
         }
 
-        public void StartReceiveMessage(BatchCompletionDelegate callback)
+        public void StartReceiveMessage(ReceivedMessageHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedMessage()));
             grpcsharp_call_recv_message(this, ctx).CheckOk();
         }
 
-        public void StartServerSide(BatchCompletionDelegate callback)
+        public void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback)
+        {
+            var ctx = BatchContextSafeHandle.Create();
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedInitialMetadata()));
+            grpcsharp_call_recv_initial_metadata(this, ctx).CheckOk();
+        }
+
+        public void StartServerSide(ReceivedCloseOnServerHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedCloseOnServerCancelled()));
             grpcsharp_call_start_serverside(this, ctx).CheckOk();
         }
 
-        public void StartSendInitialMetadata(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_initial_metadata(this, ctx, metadataArray).CheckOk();
         }
 

src/csharp/Grpc.Core/Internal/ChannelSafeHandle.cs

@@ -68,11 +68,17 @@ namespace Grpc.Core.Internal
 
         public static ChannelSafeHandle CreateInsecure(string target, ChannelArgsSafeHandle channelArgs)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_insecure_channel_create(target, channelArgs);
         }
 
         public static ChannelSafeHandle CreateSecure(CredentialsSafeHandle credentials, string target, ChannelArgsSafeHandle channelArgs)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_secure_channel_create(credentials, target, channelArgs);
         }
 
@@ -107,6 +113,7 @@ namespace Grpc.Core.Internal
         protected override bool ReleaseHandle()
         {
             grpcsharp_channel_destroy(handle);
+            GrpcEnvironment.GrpcNativeShutdown();
             return true;
         }
     }

src/csharp/Grpc.Core/Internal/ClientResponseStream.cs

@@ -72,7 +72,13 @@ namespace Grpc.Core.Internal
             call.StartReadMessage(taskSource.CompletionDelegate);
             var result = await taskSource.Task;
             this.current = result;
-            return result != null;
+
+            if (result == null)
+            {
+                await call.StreamingCallFinishedTask;
+                return false;
+            }
+            return true;
         }
 
         public void Dispose()

src/csharp/Grpc.Core/Internal/DebugStats.cs

@@ -38,10 +38,6 @@ namespace Grpc.Core.Internal
 {
     internal class DebugStats
     {
-        public readonly AtomicCounter ActiveClientCalls = new AtomicCounter();
-
-        public readonly AtomicCounter ActiveServerCalls = new AtomicCounter();
-
         public readonly AtomicCounter PendingBatchCompletions = new AtomicCounter();
 
         /// <summary>
@@ -49,16 +45,6 @@ namespace Grpc.Core.Internal
         /// </summary>
         public void CheckOK()
         {
-            var remainingClientCalls = ActiveClientCalls.Count;
-            if (remainingClientCalls != 0)
-            {                
-                DebugWarning(string.Format("Detected {0} client calls that weren't disposed properly.", remainingClientCalls));
-            }
-            var remainingServerCalls = ActiveServerCalls.Count;
-            if (remainingServerCalls != 0)
-            {
-                DebugWarning(string.Format("Detected {0} server calls that weren't disposed properly.", remainingServerCalls));
-            }
             var pendingBatchCompletions = PendingBatchCompletions.Count;
             if (pendingBatchCompletions != 0)
             {

src/csharp/Grpc.Core/Internal/GrpcThreadPool.cs

@@ -83,8 +83,6 @@ namespace Grpc.Core.Internal
             lock (myLock)
             {
                 cq.Shutdown();
-
-                Logger.Info("Waiting for GRPC threads to finish.");
                 foreach (var thread in threads)
                 {
                     thread.Join();
@@ -136,7 +134,6 @@ namespace Grpc.Core.Internal
                 }
             }
             while (ev.type != GRPCCompletionType.Shutdown);
-            Logger.Info("Completion queue has shutdown successfully, thread {0} exiting.", Thread.CurrentThread.Name);
         }
     }
 }

src/csharp/Grpc.Core/Internal/INativeCall.cs

@@ -0,0 +1,85 @@
+#region Copyright notice and license
+// Copyright 2015, Google Inc.
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// 
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+
+namespace Grpc.Core.Internal
+{
+    internal delegate void UnaryResponseClientHandler(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders);
+
+    // Received status for streaming response calls.
+    internal delegate void ReceivedStatusOnClientHandler(bool success, ClientSideStatus receivedStatus);
+
+    internal delegate void ReceivedMessageHandler(bool success, byte[] receivedMessage);
+
+    internal delegate void ReceivedResponseHeadersHandler(bool success, Metadata responseHeaders);
+
+    internal delegate void SendCompletionHandler(bool success);
+
+    internal delegate void ReceivedCloseOnServerHandler(bool success, bool cancelled);
+
+    /// <summary>
+    /// Abstraction of a native call object.
+    /// </summary>
+    internal interface INativeCall : IDisposable
+    {
+        void Cancel();
+
+        void CancelWithStatus(Grpc.Core.Status status);
+
+        string GetPeer();
+
+        void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartReceiveMessage(ReceivedMessageHandler callback);
+
+        void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback);
+
+        void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartSendMessage(SendCompletionHandler callback, byte[] payload, Grpc.Core.WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+
+        void StartSendCloseFromClient(SendCompletionHandler callback);
+
+        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+
+        void StartServerSide(ReceivedCloseOnServerHandler callback);
+    }
+}

src/csharp/Grpc.Core/Internal/ServerCallHandler.cs

@@ -67,7 +67,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -123,7 +123,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -179,7 +179,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -239,7 +239,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -278,7 +278,7 @@ namespace Grpc.Core.Internal
         {
             // We don't care about the payload type here.
             var asyncCall = new AsyncCallServer<byte[], byte[]>(
-                (payload) => payload, (payload) => payload, environment);
+                (payload) => payload, (payload) => payload, environment, newRpc.Server);
             
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();

src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs

@@ -74,6 +74,9 @@ namespace Grpc.Core.Internal
 
         public static ServerSafeHandle NewServer(CompletionQueueSafeHandle cq, ChannelArgsSafeHandle args)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_server_create(cq, args);
         }
 
@@ -109,6 +112,7 @@ namespace Grpc.Core.Internal
         protected override bool ReleaseHandle()
         {
             grpcsharp_server_destroy(handle);
+            GrpcEnvironment.GrpcNativeShutdown();
             return true;
         }
             

src/csharp/Grpc.Core/Logging/ConsoleLogger.cs

@@ -51,7 +51,19 @@ namespace Grpc.Core.Logging
         private ConsoleLogger(Type forType)
         {
             this.forType = forType;
-            this.forTypeString = forType != null ? forType.FullName + " " : "";
+            if (forType != null)
+            {
+                var namespaceStr = forType.Namespace ?? "";
+                if (namespaceStr.Length > 0)
+                {
+                     namespaceStr += ".";
+                }
+                this.forTypeString = namespaceStr + forType.Name + " ";
+            }
+            else
+            {
+                this.forTypeString = "";
+            }
         }
  
         /// <summary>

src/csharp/Grpc.Core/Server.cs

@@ -50,6 +50,8 @@ namespace Grpc.Core
     {
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Server>();
 
+        readonly AtomicCounter activeCallCounter = new AtomicCounter();
+
         readonly ServiceDefinitionCollection serviceDefinitions;
         readonly ServerPortCollection ports;
         readonly GrpcEnvironment environment;
@@ -73,7 +75,7 @@ namespace Grpc.Core
         {
             this.serviceDefinitions = new ServiceDefinitionCollection(this);
             this.ports = new ServerPortCollection(this);
-            this.environment = GrpcEnvironment.GetInstance();
+            this.environment = GrpcEnvironment.AddRef();
             this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
             using (var channelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
@@ -105,6 +107,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// To allow awaiting termination of the server.
+        /// </summary>
+        public Task ShutdownTask
+        {
+            get
+            {
+                return shutdownTcs.Task;
+            }
+        }
+
         /// <summary>
         /// Starts the server.
         /// </summary>
@@ -136,18 +149,9 @@ namespace Grpc.Core
 
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             await shutdownTcs.Task;
-            handle.Dispose();
+            DisposeHandle();
-        }
 
-        /// <summary>
+            await Task.Run(() => GrpcEnvironment.Release());
-        /// To allow awaiting termination of the server.
-        /// </summary>
-        public Task ShutdownTask
-        {
-            get
-            {
-                return shutdownTcs.Task;
-            }
         }
 
         /// <summary>
@@ -166,7 +170,22 @@ namespace Grpc.Core
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             handle.CancelAllCalls();
             await shutdownTcs.Task;
-            handle.Dispose();
+            DisposeHandle();
+        }
+
+        internal void AddCallReference(object call)
+        {
+            activeCallCounter.Increment();
+
+            bool success = false;
+            handle.DangerousAddRef(ref success);
+            Preconditions.CheckState(success);
+        }
+
+        internal void RemoveCallReference(object call)
+        {
+            handle.DangerousRelease();
+            activeCallCounter.Decrement();
         }
 
         /// <summary>
@@ -227,6 +246,16 @@ namespace Grpc.Core
             }
         }
 
+        private void DisposeHandle()
+        {
+            var activeCallCount = activeCallCounter.Count;
+            if (activeCallCount > 0)
+            {
+                Logger.Warning("Server shutdown has finished but there are still {0} active calls for that server.", activeCallCount);
+            }
+            handle.Dispose();
+        }
+
         /// <summary>
         /// Selects corresponding handler for given call and handles the call.
         /// </summary>
@@ -254,7 +283,7 @@ namespace Grpc.Core
         {
             if (success)
             {
-                ServerRpcNew newRpc = ctx.GetServerRpcNew();
+                ServerRpcNew newRpc = ctx.GetServerRpcNew(this);
 
                 // after server shutdown, the callback returns with null call
                 if (!newRpc.Call.IsInvalid)

src/csharp/Grpc.Examples.MathClient/MathClient.cs

@@ -39,23 +39,21 @@ namespace math
     {
         public static void Main(string[] args)
         {
-            using (Channel channel = new Channel("127.0.0.1", 23456, Credentials.Insecure))
+            var channel = new Channel("127.0.0.1", 23456, Credentials.Insecure);
-            {
+            Math.IMathClient client = new Math.MathClient(channel);
-                Math.IMathClient client = new Math.MathClient(channel);
+            MathExamples.DivExample(client);
-                MathExamples.DivExample(client);
 
-                MathExamples.DivAsyncExample(client).Wait();
+            MathExamples.DivAsyncExample(client).Wait();
 
-                MathExamples.FibExample(client).Wait();
+            MathExamples.FibExample(client).Wait();
 
-                MathExamples.SumExample(client).Wait();
+            MathExamples.SumExample(client).Wait();
 
-                MathExamples.DivManyExample(client).Wait();
+            MathExamples.DivManyExample(client).Wait();
 
-                MathExamples.DependendRequestsExample(client).Wait();
+            MathExamples.DependendRequestsExample(client).Wait();
-            }
 
-            GrpcEnvironment.Shutdown();
+            channel.ShutdownAsync().Wait();
         }
     }
 }

src/csharp/Grpc.Examples.MathServer/MathServer.cs

@@ -56,7 +56,6 @@ namespace math
             Console.ReadKey();
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
     }
 }

src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs

@@ -68,9 +68,8 @@ namespace math.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]

src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs

@@ -71,10 +71,9 @@ namespace Grpc.HealthCheck.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

@@ -120,12 +120,10 @@ namespace Grpc.IntegrationTesting
                 };
             }
 
-            using (Channel channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions))
+            var channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions);
-            {
+            TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
-                TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
+            await RunTestCaseAsync(options.testCase, client);
-                await RunTestCaseAsync(options.testCase, client);
+            channel.ShutdownAsync().Wait();
-            }
-            GrpcEnvironment.Shutdown();
         }
 
         private async Task RunTestCaseAsync(string testCase, TestService.TestServiceClient client)
@@ -171,6 +169,9 @@ namespace Grpc.IntegrationTesting
                 case "cancel_after_first_response":
                     await RunCancelAfterFirstResponseAsync(client);
                     break;
+                case "timeout_on_sleeping_server":
+                    await RunTimeoutOnSleepingServerAsync(client);
+                    break;
                 case "benchmark_empty_unary":
                     RunBenchmarkEmptyUnary(client);
                     break;
@@ -460,6 +461,29 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("Passed!");
         }
 
+        public static async Task RunTimeoutOnSleepingServerAsync(TestService.ITestServiceClient client)
+        {
+            Console.WriteLine("running timeout_on_sleeping_server");
+
+            var deadline = DateTime.UtcNow.AddMilliseconds(1);
+            using (var call = client.FullDuplexCall(deadline: deadline))
+            {
+                try
+                {
+                    await call.RequestStream.WriteAsync(StreamingOutputCallRequest.CreateBuilder()
+                        .SetPayload(CreateZerosPayload(27182)).Build());
+                }
+                catch (InvalidOperationException)
+                {
+                    // Deadline was reached before write has started. Eat the exception and continue.
+                }
+
+                var ex = Assert.Throws<RpcException>(async () => await call.ResponseStream.MoveNext());
+                Assert.AreEqual(StatusCode.DeadlineExceeded, ex.Status.StatusCode);
+            }
+            Console.WriteLine("Passed!");
+        }
+
         // This is not an official interop test, but it's useful.
         public static void RunBenchmarkEmptyUnary(TestService.ITestServiceClient client)
         {

src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

@@ -75,9 +75,8 @@ namespace Grpc.IntegrationTesting
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -127,5 +126,11 @@ namespace Grpc.IntegrationTesting
         {
             await InteropClient.RunCancelAfterFirstResponseAsync(client);
         }
+
+        [Test]
+        public async Task TimeoutOnSleepingServerAsync()
+        {
+            await InteropClient.RunTimeoutOnSleepingServerAsync(client);
+        }
     }
 }

src/csharp/Grpc.IntegrationTesting/InteropServer.cs

@@ -107,8 +107,6 @@ namespace Grpc.IntegrationTesting
             server.Start();
 
             server.ShutdownTask.Wait();
-
-            GrpcEnvironment.Shutdown();
         }
 
         private static ServerOptions ParseArguments(string[] args)

src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs

@@ -85,9 +85,8 @@ namespace Grpc.IntegrationTesting
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]

src/csharp/ext/grpc_csharp_ext.c

@@ -595,7 +595,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
     grpc_call *call, grpcsharp_batch_context *ctx, const char *send_buffer,
     size_t send_buffer_len, grpc_metadata_array *initial_metadata, gpr_uint32 write_flags) {
   /* TODO: don't use magic number */
-  grpc_op ops[5];
+  grpc_op ops[4];
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -615,23 +615,18 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
   ops[2].flags = 0;
   ops[2].reserved = NULL;
 
-  ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
+  ops[3].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+  ops[3].data.recv_status_on_client.trailing_metadata =
-  ops[3].flags = 0;
-  ops[3].reserved = NULL;
-
-  ops[4].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[4].data.recv_status_on_client.trailing_metadata =
       &(ctx->recv_status_on_client.trailing_metadata);
-  ops[4].data.recv_status_on_client.status =
+  ops[3].data.recv_status_on_client.status =
       &(ctx->recv_status_on_client.status);
   /* not using preallocation for status_details */
-  ops[4].data.recv_status_on_client.status_details =
+  ops[3].data.recv_status_on_client.status_details =
       &(ctx->recv_status_on_client.status_details);
-  ops[4].data.recv_status_on_client.status_details_capacity =
+  ops[3].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
-  ops[4].flags = 0;
+  ops[3].flags = 0;
-  ops[4].reserved = NULL;
+  ops[3].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -642,7 +637,7 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
                                       grpcsharp_batch_context *ctx,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
-  grpc_op ops[3];
+  grpc_op ops[2];
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -652,28 +647,36 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
   ops[0].flags = 0;
   ops[0].reserved = NULL;
 
-  ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
+  ops[1].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+  ops[1].data.recv_status_on_client.trailing_metadata =
-  ops[1].flags = 0;
-  ops[1].reserved = NULL;
-
-  ops[2].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[2].data.recv_status_on_client.trailing_metadata =
       &(ctx->recv_status_on_client.trailing_metadata);
-  ops[2].data.recv_status_on_client.status =
+  ops[1].data.recv_status_on_client.status =
       &(ctx->recv_status_on_client.status);
   /* not using preallocation for status_details */
-  ops[2].data.recv_status_on_client.status_details =
+  ops[1].data.recv_status_on_client.status_details =
       &(ctx->recv_status_on_client.status_details);
-  ops[2].data.recv_status_on_client.status_details_capacity =
+  ops[1].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
-  ops[2].flags = 0;
+  ops[1].flags = 0;
-  ops[2].reserved = NULL;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
 }
 
+GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_recv_initial_metadata(
+	grpc_call *call, grpcsharp_batch_context *ctx) {
+	/* TODO: don't use magic number */
+	grpc_op ops[1];
+	ops[0].op = GRPC_OP_RECV_INITIAL_METADATA;
+	ops[0].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+	ops[0].flags = 0;
+	ops[0].reserved = NULL;
+
+	return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
+		NULL);
+}
+
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
                             const char *send_buffer, size_t send_buffer_len,

src/node/ext/server_credentials.cc

@@ -41,6 +41,7 @@
 namespace grpc {
 namespace node {
 
+using v8::Array;
 using v8::Exception;
 using v8::External;
 using v8::Function;
@@ -52,6 +53,7 @@ using v8::Local;
 using v8::Object;
 using v8::ObjectTemplate;
 using v8::Persistent;
+using v8::String;
 using v8::Value;
 
 NanCallback *ServerCredentials::constructor;
@@ -122,25 +124,66 @@ NAN_METHOD(ServerCredentials::CreateSsl) {
   // TODO: have the node API support multiple key/cert pairs.
   NanScope();
   char *root_certs = NULL;
-  grpc_ssl_pem_key_cert_pair key_cert_pair;
   if (::node::Buffer::HasInstance(args[0])) {
     root_certs = ::node::Buffer::Data(args[0]);
   } else if (!(args[0]->IsNull() || args[0]->IsUndefined())) {
     return NanThrowTypeError(
         "createSSl's first argument must be a Buffer if provided");
   }
-  if (!::node::Buffer::HasInstance(args[1])) {
+  if (!args[1]->IsArray()) {
-    return NanThrowTypeError("createSsl's second argument must be a Buffer");
+    return NanThrowTypeError(
+        "createSsl's second argument must be a list of objects");
+  }
+  int force_client_auth = 0;
+  if (args[2]->IsBoolean()) {
+    force_client_auth = (int)args[2]->BooleanValue();
+  } else if (!(args[2]->IsUndefined() || args[2]->IsNull())) {
+    return NanThrowTypeError(
+        "createSsl's third argument must be a boolean if provided");
   }
-  key_cert_pair.private_key = ::node::Buffer::Data(args[1]);
+  Handle<Array> pair_list = Local<Array>::Cast(args[1]);
-  if (!::node::Buffer::HasInstance(args[2])) {
+  uint32_t key_cert_pair_count = pair_list->Length();
-    return NanThrowTypeError("createSsl's third argument must be a Buffer");
+  grpc_ssl_pem_key_cert_pair *key_cert_pairs = new grpc_ssl_pem_key_cert_pair[
+      key_cert_pair_count];
+
+  Handle<String> key_key = NanNew("private_key");
+  Handle<String> cert_key = NanNew("cert_chain");
+
+  for(uint32_t i = 0; i < key_cert_pair_count; i++) {
+    if (!pair_list->Get(i)->IsObject()) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("Key/cert pairs must be objects");
+    }
+    Handle<Object> pair_obj = pair_list->Get(i)->ToObject();
+    if (!pair_obj->HasOwnProperty(key_key)) {
+      delete key_cert_pairs;
+      return NanThrowTypeError(
+          "Key/cert pairs must have a private_key and a cert_chain");
+    }
+    if (!pair_obj->HasOwnProperty(cert_key)) {
+      delete key_cert_pairs;
+      return NanThrowTypeError(
+          "Key/cert pairs must have a private_key and a cert_chain");
+    }
+    if (!::node::Buffer::HasInstance(pair_obj->Get(key_key))) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("private_key must be a Buffer");
+    }
+    if (!::node::Buffer::HasInstance(pair_obj->Get(cert_key))) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("cert_chain must be a Buffer");
+    }
+    key_cert_pairs[i].private_key = ::node::Buffer::Data(
+        pair_obj->Get(key_key));
+    key_cert_pairs[i].cert_chain = ::node::Buffer::Data(
+        pair_obj->Get(cert_key));
   }
-  key_cert_pair.cert_chain = ::node::Buffer::Data(args[2]);
-  // TODO Add a force_client_auth parameter and pass it as the last parameter
-  // here.
   grpc_server_credentials *creds =
-      grpc_ssl_server_credentials_create(root_certs, &key_cert_pair, 1, 0);
+      grpc_ssl_server_credentials_create(root_certs,
+                                         key_cert_pairs,
+                                         key_cert_pair_count,
+                                         force_client_auth);
+  delete key_cert_pairs;
   if (creds == NULL) {
     NanReturnNull();
   }

src/node/health_check/health.js

@@ -45,17 +45,13 @@ function HealthImplementation(statusMap) {
   this.statusMap = _.clone(statusMap);
 }
 
-HealthImplementation.prototype.setStatus = function(host, service, status) {
+HealthImplementation.prototype.setStatus = function(service, status) {
-  if (!this.statusMap[host]) {
+  this.statusMap[service] = status;
-    this.statusMap[host] = {};
-  }
-  this.statusMap[host][service] = status;
 };
 
 HealthImplementation.prototype.check = function(call, callback){
-  var host = call.request.host;
   var service = call.request.service;
-  var status = _.get(this.statusMap, [host, service], null);
+  var status = _.get(this.statusMap, service, null);
   if (status === null) {
     callback({code:grpc.status.NOT_FOUND});
   } else {

src/node/health_check/health.proto

@@ -32,8 +32,7 @@ syntax = "proto3";
 package grpc.health.v1alpha;
 
 message HealthCheckRequest {
-  string host = 1;
+  string service = 1;
-  string service = 2;
 }
 
 message HealthCheckResponse {
@@ -47,4 +46,4 @@ message HealthCheckResponse {
 
 service Health {
   rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
-}
+}

src/node/interop/interop_server.js

@@ -169,8 +169,8 @@ function getServer(port, tls) {
     var key_data = fs.readFileSync(key_path);
     var pem_data = fs.readFileSync(pem_path);
     server_creds = grpc.ServerCredentials.createSsl(null,
-                                                    key_data,
+                                                    [{private_key: key_data,
-                                                    pem_data);
+                                                      cert_chain: pem_data}]);
   } else {
     server_creds = grpc.ServerCredentials.createInsecure();
   }

src/node/test/health_test.js

@@ -41,13 +41,9 @@ var grpc = require('../');
 
 describe('Health Checking', function() {
   var statusMap = {
-    '': {
+    '': 'SERVING',
-      '': 'SERVING',
+    'grpc.test.TestServiceNotServing': 'NOT_SERVING',
-      'grpc.test.TestService': 'NOT_SERVING',
+    'grpc.test.TestServiceServing': 'SERVING'
-    },
-    virtual_host: {
-      'grpc.test.TestService': 'SERVING'
-    }
   };
   var healthServer = new grpc.Server();
   healthServer.addProtoService(health.service,
@@ -71,15 +67,15 @@ describe('Health Checking', function() {
     });
   });
   it('should say that a disabled service is NOT_SERVING', function(done) {
-    healthClient.check({service: 'grpc.test.TestService'},
+    healthClient.check({service: 'grpc.test.TestServiceNotServing'},
                        function(err, response) {
                          assert.ifError(err);
                          assert.strictEqual(response.status, 'NOT_SERVING');
                          done();
                        });
   });
-  it('should say that a service on another host is SERVING', function(done) {
+  it('should say that an enabled service is SERVING', function(done) {
-    healthClient.check({host: 'virtual_host', service: 'grpc.test.TestService'},
+    healthClient.check({service: 'grpc.test.TestServiceServing'},
                        function(err, response) {
                          assert.ifError(err);
                          assert.strictEqual(response.status, 'SERVING');
@@ -93,12 +89,4 @@ describe('Health Checking', function() {
       done();
     });
   });
-  it('should get NOT_FOUND if the host is not registered', function(done) {
-    healthClient.check({host: 'wrong_host', service: 'grpc.test.TestService'},
-                       function(err, response) {
-                         assert(err);
-                         assert.strictEqual(err.code, grpc.status.NOT_FOUND);
-                         done();
-                       });
-  });
 });

src/node/test/server_test.js

@@ -70,7 +70,9 @@ describe('server', function() {
       var pem_path = path.join(__dirname, '../test/data/server1.pem');
       var key_data = fs.readFileSync(key_path);
       var pem_data = fs.readFileSync(pem_path);
-      var creds = grpc.ServerCredentials.createSsl(null, key_data, pem_data);
+      var creds = grpc.ServerCredentials.createSsl(null,
+                                                   [{private_key: key_data,
+                                                     cert_chain: pem_data}]);
       assert.doesNotThrow(function() {
         port = server.addHttp2Port('0.0.0.0:0', creds);
       });

src/php/tests/generated_code/AbstractGeneratedCodeTest.php

@@ -39,6 +39,14 @@ abstract class AbstractGeneratedCodeTest extends PHPUnit_Framework_TestCase {
   protected static $client;
   protected static $timeout;
 
+  public function testWaitForNotReady() {
+    $this->assertFalse(self::$client->waitForReady(1));
+  }
+
+  public function testWaitForReady() {
+    $this->assertTrue(self::$client->waitForReady(250000));
+  }
+
   public function testSimpleRequest() {
     $div_arg = new math\DivArgs();
     $div_arg->setDividend(7);

src/php/tests/generated_code/GeneratedCodeTest.php

@@ -35,7 +35,7 @@ require 'AbstractGeneratedCodeTest.php';
 
 class GeneratedCodeTest extends AbstractGeneratedCodeTest {
   public static function setUpBeforeClass() {
-    self::$client = new math\MathClient(new Grpc\BaseStub(
+    self::$client = new math\MathClient(
-        getenv('GRPC_TEST_HOST'), []));
+        getenv('GRPC_TEST_HOST'), []);
   }
 }

src/php/tests/generated_code/GeneratedCodeWithCallbackTest.php

@@ -35,13 +35,13 @@ require 'AbstractGeneratedCodeTest.php';
 
 class GeneratedCodeWithCallbackTest extends AbstractGeneratedCodeTest {
   public static function setUpBeforeClass() {
-    self::$client = new math\MathClient(new Grpc\BaseStub(
+    self::$client = new math\MathClient(
         getenv('GRPC_TEST_HOST'), ['update_metadata' =>
                                    function($a_hash,
                                             $client = array()) {
                                      $a_copy = $a_hash;
                                      $a_copy['foo'] = ['bar'];
                                      return $a_copy;
-                                   }]));
+                                   }]);
   }
 }

src/python/grpcio/grpc/_adapter/_c/types.h

@@ -146,6 +146,7 @@ typedef struct Server {
   PyObject_HEAD
   grpc_server *c_serv;
   CompletionQueue *cq;
+  int shutdown_called;
 } Server;
 Server *pygrpc_Server_new(PyTypeObject *type, PyObject *args, PyObject *kwargs);
 void pygrpc_Server_dealloc(Server *self);
@@ -156,6 +157,7 @@ PyObject *pygrpc_Server_add_http2_port(
 PyObject *pygrpc_Server_start(Server *self, PyObject *ignored);
 PyObject *pygrpc_Server_shutdown(
     Server *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Server_cancel_all_calls(Server *self, PyObject *unused);
 extern PyTypeObject pygrpc_Server_type;
 
 /*=========*/

src/python/grpcio/grpc/_adapter/_c/types/server.c

@@ -45,6 +45,8 @@ PyMethodDef pygrpc_Server_methods[] = {
      METH_KEYWORDS, ""},
     {"start", (PyCFunction)pygrpc_Server_start, METH_NOARGS, ""},
     {"shutdown", (PyCFunction)pygrpc_Server_shutdown, METH_KEYWORDS, ""},
+    {"cancel_all_calls", (PyCFunction)pygrpc_Server_cancel_all_calls,
+     METH_NOARGS, ""},
     {NULL}
 };
 const char pygrpc_Server_doc[] = "See grpc._adapter._types.Server.";
@@ -109,6 +111,7 @@ Server *pygrpc_Server_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
   pygrpc_discard_channel_args(c_args);
   self->cq = cq;
   Py_INCREF(self->cq);
+  self->shutdown_called = 0;
   return self;
 }
 
@@ -163,6 +166,7 @@ PyObject *pygrpc_Server_add_http2_port(
 
 PyObject *pygrpc_Server_start(Server *self, PyObject *ignored) {
   grpc_server_start(self->c_serv);
+  self->shutdown_called = 0;
   Py_RETURN_NONE;
 }
 
@@ -176,5 +180,17 @@ PyObject *pygrpc_Server_shutdown(
   }
   tag = pygrpc_produce_server_shutdown_tag(user_tag);
   grpc_server_shutdown_and_notify(self->c_serv, self->cq->c_cq, tag);
+  self->shutdown_called = 1;
+  Py_RETURN_NONE;
+}
+
+PyObject *pygrpc_Server_cancel_all_calls(Server *self, PyObject *unused) {
+  if (!self->shutdown_called) {
+    PyErr_SetString(
+        PyExc_RuntimeError,
+        "shutdown must have been called prior to calling cancel_all_calls!");
+    return NULL;
+  }
+  grpc_server_cancel_all_calls(self->c_serv);
   Py_RETURN_NONE;
 }

src/python/grpcio/grpc/_adapter/_low.py

@@ -124,3 +124,6 @@ class Server(_types.Server):
 
   def request_call(self, completion_queue, tag):
     return self.server.request_call(completion_queue.completion_queue, tag)
+
+  def cancel_all_calls(self):
+    return self.server.cancel_all_calls()

src/python/grpcio/grpc/framework/core/__init__.py

@@ -0,0 +1,30 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+

src/python/grpcio/grpc/framework/core/_constants.py

@@ -0,0 +1,59 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Private constants for the package."""
+
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.links import links
+
+TICKET_SUBSCRIPTION_FOR_BASE_SUBSCRIPTION_KIND = {
+    base.Subscription.Kind.NONE: links.Ticket.Subscription.NONE,
+    base.Subscription.Kind.TERMINATION_ONLY:
+        links.Ticket.Subscription.TERMINATION,
+    base.Subscription.Kind.FULL: links.Ticket.Subscription.FULL,
+    }
+
+# Mapping from abortive operation outcome to ticket termination to be
+# sent to the other side of the operation, or None to indicate that no
+# ticket should be sent to the other side in the event of such an
+# outcome.
+ABORTION_OUTCOME_TO_TICKET_TERMINATION = {
+    base.Outcome.CANCELLED: links.Ticket.Termination.CANCELLATION,
+    base.Outcome.EXPIRED: links.Ticket.Termination.EXPIRATION,
+    base.Outcome.LOCAL_SHUTDOWN: links.Ticket.Termination.SHUTDOWN,
+    base.Outcome.REMOTE_SHUTDOWN: None,
+    base.Outcome.RECEPTION_FAILURE: links.Ticket.Termination.RECEPTION_FAILURE,
+    base.Outcome.TRANSMISSION_FAILURE: None,
+    base.Outcome.LOCAL_FAILURE: links.Ticket.Termination.LOCAL_FAILURE,
+    base.Outcome.REMOTE_FAILURE: links.Ticket.Termination.REMOTE_FAILURE,
+}
+
+INTERNAL_ERROR_LOG_MESSAGE = ':-( RPC Framework (Core) internal error! )-:'
+TERMINATION_CALLBACK_EXCEPTION_LOG_MESSAGE = (
+    'Exception calling termination callback!')

src/python/grpcio/grpc/framework/core/_context.py

@@ -0,0 +1,92 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for operation context."""
+
+import time
+
+# _interfaces is referenced from specification in this module.
+from grpc.framework.core import _interfaces  # pylint: disable=unused-import
+from grpc.framework.interfaces.base import base
+
+
+class OperationContext(base.OperationContext):
+  """An implementation of interfaces.OperationContext."""
+
+  def __init__(
+      self, lock, termination_manager, transmission_manager,
+      expiration_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+
+  def _abort(self, outcome):
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        self._termination_manager.abort(outcome)
+        self._transmission_manager.abort(outcome)
+        self._expiration_manager.terminate()
+
+  def outcome(self):
+    """See base.OperationContext.outcome for specification."""
+    with self._lock:
+      return self._termination_manager.outcome
+
+  def add_termination_callback(self, callback):
+    """See base.OperationContext.add_termination_callback."""
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        self._termination_manager.add_callback(callback)
+        return None
+      else:
+        return self._termination_manager.outcome
+
+  def time_remaining(self):
+    """See base.OperationContext.time_remaining for specification."""
+    with self._lock:
+      deadline = self._expiration_manager.deadline()
+    return max(0.0, deadline - time.time())
+
+  def cancel(self):
+    """See base.OperationContext.cancel for specification."""
+    self._abort(base.Outcome.CANCELLED)
+
+  def fail(self, exception):
+    """See base.OperationContext.fail for specification."""
+    self._abort(base.Outcome.LOCAL_FAILURE)

src/python/grpcio/grpc/framework/core/_emission.py

@@ -0,0 +1,97 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for handling emitted values."""
+
+from grpc.framework.core import _interfaces
+from grpc.framework.interfaces.base import base
+
+
+class EmissionManager(_interfaces.EmissionManager):
+  """An EmissionManager implementation."""
+
+  def __init__(
+      self, lock, termination_manager, transmission_manager,
+      expiration_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+    self._ingestion_manager = None
+
+    self._initial_metadata_seen = False
+    self._payload_seen = False
+    self._completion_seen = False
+
+  def set_ingestion_manager(self, ingestion_manager):
+    """Sets the ingestion manager with which this manager will cooperate.
+
+    Args:
+      ingestion_manager: The _interfaces.IngestionManager for the operation.
+    """
+    self._ingestion_manager = ingestion_manager
+
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    initial_metadata_present = initial_metadata is not None
+    payload_present = payload is not None
+    completion_present = completion is not None
+    allowance_present = allowance is not None
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        if (initial_metadata_present and (
+                self._initial_metadata_seen or self._payload_seen or
+                self._completion_seen) or
+            payload_present and self._completion_seen or
+            completion_present and self._completion_seen or
+            allowance_present and allowance <= 0):
+          self._termination_manager.abort(base.Outcome.LOCAL_FAILURE)
+          self._transmission_manager.abort(base.Outcome.LOCAL_FAILURE)
+          self._expiration_manager.terminate()
+        else:
+          self._initial_metadata_seen |= initial_metadata_present
+          self._payload_seen |= payload_present
+          self._completion_seen |= completion_present
+          if completion_present:
+            self._termination_manager.emission_complete()
+            self._ingestion_manager.local_emissions_done()
+          self._transmission_manager.advance(
+              initial_metadata, payload, completion, allowance)
+          if allowance_present:
+            self._ingestion_manager.add_local_allowance(allowance)

src/python/grpcio/grpc/framework/core/_end.py

@@ -0,0 +1,251 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Implementation of base.End."""
+
+import abc
+import enum
+import threading
+import uuid
+
+from grpc.framework.core import _operation
+from grpc.framework.core import _utilities
+from grpc.framework.foundation import callable_util
+from grpc.framework.foundation import later
+from grpc.framework.foundation import logging_pool
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.links import links
+from grpc.framework.interfaces.links import utilities
+
+_IDLE_ACTION_EXCEPTION_LOG_MESSAGE = 'Exception calling idle action!'
+
+
+class End(base.End, links.Link):
+  """A bridge between base.End and links.Link.
+
+  Implementations of this interface translate arriving tickets into
+  calls on application objects implementing base interfaces and
+  translate calls from application objects implementing base interfaces
+  into tickets sent to a joined link.
+  """
+  __metaclass__ = abc.ABCMeta
+
+
+class _Cycle(object):
+  """State for a single start-stop End lifecycle."""
+
+  def __init__(self, pool):
+    self.pool = pool
+    self.grace = False
+    self.futures = []
+    self.operations = {}
+    self.idle_actions = []
+
+
+def _abort(operations):
+  for operation in operations:
+    operation.abort(base.Outcome.LOCAL_SHUTDOWN)
+
+
+def _cancel_futures(futures):
+  for future in futures:
+    futures.cancel()
+
+
+def _future_shutdown(lock, cycle, event):
+  def in_future():
+    with lock:
+      _abort(cycle.operations.values())
+      _cancel_futures(cycle.futures)
+      pool = cycle.pool
+    cycle.pool.shutdown(wait=True)
+  return in_future
+
+
+def _termination_action(lock, stats, operation_id, cycle):
+  """Constructs the termination action for a single operation.
+
+  Args:
+    lock: A lock to hold during the termination action.
+    states: A mapping from base.Outcome values to integers to increment with
+      the outcome given to the termination action.
+    operation_id: The operation ID for the termination action.
+    cycle: A _Cycle value to be updated during the termination action.
+
+  Returns:
+    A callable that takes an operation outcome as its sole parameter and that
+      should be used as the termination action for the operation associated
+      with the given operation ID.
+  """
+  def termination_action(outcome):
+    with lock:
+      stats[outcome] += 1
+      cycle.operations.pop(operation_id, None)
+      if not cycle.operations:
+        for action in cycle.idle_actions:
+          cycle.pool.submit(action)
+        cycle.idle_actions = []
+        if cycle.grace:
+          _cancel_futures(cycle.futures)
+  return termination_action
+
+
+class _End(End):
+  """An End implementation."""
+
+  def __init__(self, servicer_package):
+    """Constructor.
+
+    Args:
+      servicer_package: A _ServicerPackage for servicing operations or None if
+        this end will not be used to service operations.
+    """
+    self._lock = threading.Condition()
+    self._servicer_package = servicer_package
+
+    self._stats = {outcome: 0 for outcome in base.Outcome}
+
+    self._mate = None
+
+    self._cycle = None
+
+  def start(self):
+    """See base.End.start for specification."""
+    with self._lock:
+      if self._cycle is not None:
+        raise ValueError('Tried to start a not-stopped End!')
+      else:
+        self._cycle = _Cycle(logging_pool.pool(1))
+
+  def stop(self, grace):
+    """See base.End.stop for specification."""
+    with self._lock:
+      if self._cycle is None:
+        event = threading.Event()
+        event.set()
+        return event
+      elif not self._cycle.operations:
+        event = threading.Event()
+        self._cycle.pool.submit(event.set)
+        self._cycle.pool.shutdown(wait=False)
+        self._cycle = None
+        return event
+      else:
+        self._cycle.grace = True
+        event = threading.Event()
+        self._cycle.idle_actions.append(event.set)
+        if 0 < grace:
+          future = later.later(
+              grace, _future_shutdown(self._lock, self._cycle, event))
+          self._cycle.futures.append(future)
+        else:
+          _abort(self._cycle.operations.values())
+        return event
+
+  def operate(
+      self, group, method, subscription, timeout, initial_metadata=None,
+      payload=None, completion=None):
+    """See base.End.operate for specification."""
+    operation_id = uuid.uuid4()
+    with self._lock:
+      if self._cycle is None or self._cycle.grace:
+        raise ValueError('Can\'t operate on stopped or stopping End!')
+      termination_action = _termination_action(
+          self._lock, self._stats, operation_id, self._cycle)
+      operation = _operation.invocation_operate(
+          operation_id, group, method, subscription, timeout, initial_metadata,
+          payload, completion, self._mate.accept_ticket, termination_action,
+          self._cycle.pool)
+      self._cycle.operations[operation_id] = operation
+      return operation.context, operation.operator
+
+  def operation_stats(self):
+    """See base.End.operation_stats for specification."""
+    with self._lock:
+      return dict(self._stats)
+
+  def add_idle_action(self, action):
+    """See base.End.add_idle_action for specification."""
+    with self._lock:
+      if self._cycle is None:
+        raise ValueError('Can\'t add idle action to stopped End!')
+      action_with_exceptions_logged = callable_util.with_exceptions_logged(
+          action, _IDLE_ACTION_EXCEPTION_LOG_MESSAGE)
+      if self._cycle.operations:
+        self._cycle.idle_actions.append(action_with_exceptions_logged)
+      else:
+        self._cycle.pool.submit(action_with_exceptions_logged)
+
+  def accept_ticket(self, ticket):
+    """See links.Link.accept_ticket for specification."""
+    with self._lock:
+      if self._cycle is not None and not self._cycle.grace:
+        operation = self._cycle.operations.get(ticket.operation_id)
+        if operation is not None:
+          operation.handle_ticket(ticket)
+        elif self._servicer_package is not None:
+          termination_action = _termination_action(
+              self._lock, self._stats, ticket.operation_id, self._cycle)
+          operation = _operation.service_operate(
+              self._servicer_package, ticket, self._mate.accept_ticket,
+              termination_action, self._cycle.pool)
+          if operation is not None:
+            self._cycle.operations[ticket.operation_id] = operation
+
+  def join_link(self, link):
+    """See links.Link.join_link for specification."""
+    with self._lock:
+      self._mate = utilities.NULL_LINK if link is None else link
+
+
+def serviceless_end_link():
+  """Constructs an End usable only for invoking operations.
+
+  Returns:
+    An End usable for translating operations into ticket exchange.
+  """
+  return _End(None)
+
+
+def serviceful_end_link(servicer, default_timeout, maximum_timeout):
+  """Constructs an End capable of servicing operations.
+
+  Args:
+    servicer: An interfaces.Servicer for servicing operations.
+    default_timeout: A length of time in seconds to be used as the default
+      time alloted for a single operation.
+    maximum_timeout: A length of time in seconds to be used as the maximum
+      time alloted for a single operation.
+
+  Returns:
+    An End capable of servicing the operations requested of it through ticket
+      exchange.
+  """
+  return _End(
+      _utilities.ServicerPackage(servicer, default_timeout, maximum_timeout))

src/python/grpcio/grpc/framework/core/_expiration.py

@@ -0,0 +1,152 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for operation expiration."""
+
+import time
+
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import later
+from grpc.framework.interfaces.base import base
+
+
+class _ExpirationManager(_interfaces.ExpirationManager):
+  """An implementation of _interfaces.ExpirationManager."""
+
+  def __init__(
+      self, commencement, timeout, maximum_timeout, lock, termination_manager,
+      transmission_manager):
+    """Constructor.
+
+    Args:
+      commencement: The time in seconds since the epoch at which the operation
+        began.
+      timeout: A length of time in seconds to allow for the operation to run.
+      maximum_timeout: The maximum length of time in seconds to allow for the
+        operation to run despite what is requested via this object's
+        change_timout method.
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._commencement = commencement
+    self._maximum_timeout = maximum_timeout
+
+    self._timeout = timeout
+    self._deadline = commencement + timeout
+    self._index = None
+    self._future = None
+
+  def _expire(self, index):
+    def expire():
+      with self._lock:
+        if self._future is not None and index == self._index:
+          self._future = None
+          self._termination_manager.expire()
+          self._transmission_manager.abort(base.Outcome.EXPIRED)
+    return expire
+
+  def start(self):
+    self._index = 0
+    self._future = later.later(self._timeout, self._expire(0))
+
+  def change_timeout(self, timeout):
+    if self._future is not None and timeout != self._timeout:
+      self._future.cancel()
+      new_timeout = min(timeout, self._maximum_timeout)
+      new_index = self._index + 1
+      self._timeout = new_timeout
+      self._deadline = self._commencement + new_timeout
+      self._index = new_index
+      delay = self._deadline - time.time()
+      self._future = later.later(delay, self._expire(new_index))
+      if new_timeout != timeout:
+        self._transmission_manager.timeout(new_timeout)
+
+  def deadline(self):
+    return self._deadline
+
+  def terminate(self):
+    if self._future:
+      self._future.cancel()
+      self._future = None
+    self._deadline_index = None
+
+
+def invocation_expiration_manager(
+    timeout, lock, termination_manager, transmission_manager):
+  """Creates an _interfaces.ExpirationManager appropriate for front-side use.
+
+  Args:
+    timeout: A length of time in seconds to allow for the operation to run.
+    lock: The operation-wide lock.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+
+  Returns:
+    An _interfaces.ExpirationManager appropriate for invocation-side use.
+  """
+  expiration_manager = _ExpirationManager(
+      time.time(), timeout, timeout, lock, termination_manager,
+      transmission_manager)
+  expiration_manager.start()
+  return expiration_manager
+
+
+def service_expiration_manager(
+    timeout, default_timeout, maximum_timeout, lock, termination_manager,
+    transmission_manager):
+  """Creates an _interfaces.ExpirationManager appropriate for back-side use.
+
+  Args:
+    timeout: A length of time in seconds to allow for the operation to run. May
+      be None in which case default_timeout will be used.
+    default_timeout: The default length of time in seconds to allow for the
+      operation to run if the front-side customer has not specified such a value
+      (or if the value they specified is not yet known).
+    maximum_timeout: The maximum length of time in seconds to allow for the
+      operation to run.
+    lock: The operation-wide lock.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+
+  Returns:
+    An _interfaces.ExpirationManager appropriate for service-side use.
+  """
+  expiration_manager = _ExpirationManager(
+      time.time(), default_timeout if timeout is None else timeout,
+      maximum_timeout, lock, termination_manager, transmission_manager)
+  expiration_manager.start()
+  return expiration_manager

src/python/grpcio/grpc/framework/core/_ingestion.py

@@ -0,0 +1,410 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for ingestion during an operation."""
+
+import abc
+import collections
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import abandonment
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+
+_CREATE_SUBSCRIPTION_EXCEPTION_LOG_MESSAGE = 'Exception initializing ingestion!'
+_INGESTION_EXCEPTION_LOG_MESSAGE = 'Exception during ingestion!'
+
+
+class _SubscriptionCreation(collections.namedtuple(
+    '_SubscriptionCreation', ('subscription', 'remote_error', 'abandoned'))):
+  """A sum type for the outcome of ingestion initialization.
+
+  Either subscription will be non-None, remote_error will be True, or abandoned
+  will be True.
+
+  Attributes:
+    subscription: A base.Subscription describing the customer's interest in
+      operation values from the other side.
+    remote_error: A boolean indicating that the subscription could not be
+      created due to an error on the remote side of the operation.
+    abandoned: A boolean indicating that subscription creation was abandoned.
+  """
+
+
+class _SubscriptionCreator(object):
+  """Common specification of subscription-creating behavior."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def create(self, group, method):
+    """Creates the base.Subscription of the local customer.
+
+    Any exceptions raised by this method should be attributed to and treated as
+    defects in the customer code called by this method.
+
+    Args:
+      group: The group identifier of the operation.
+      method: The method identifier of the operation.
+
+    Returns:
+      A _SubscriptionCreation describing the result of subscription creation.
+    """
+    raise NotImplementedError()
+
+
+class _ServiceSubscriptionCreator(_SubscriptionCreator):
+  """A _SubscriptionCreator appropriate for service-side use."""
+
+  def __init__(self, servicer, operation_context, output_operator):
+    """Constructor.
+
+    Args:
+      servicer: The base.Servicer that will service the operation.
+      operation_context: A base.OperationContext for the operation to be passed
+        to the customer.
+      output_operator: A base.Operator for the operation to be passed to the
+        customer and to be called by the customer to accept operation data
+        emitted by the customer.
+    """
+    self._servicer = servicer
+    self._operation_context = operation_context
+    self._output_operator = output_operator
+
+  def create(self, group, method):
+    try:
+      subscription = self._servicer.service(
+          group, method, self._operation_context, self._output_operator)
+    except base.NoSuchMethodError:
+      return _SubscriptionCreation(None, True, False)
+    except abandonment.Abandoned:
+      return _SubscriptionCreation(None, False, True)
+    else:
+      return _SubscriptionCreation(subscription, False, False)
+
+
+def _wrap(behavior):
+  def wrapped(*args, **kwargs):
+    try:
+      behavior(*args, **kwargs)
+    except abandonment.Abandoned:
+      return False
+    else:
+      return True
+  return wrapped
+
+
+class _IngestionManager(_interfaces.IngestionManager):
+  """An implementation of _interfaces.IngestionManager."""
+
+  def __init__(
+      self, lock, pool, subscription, subscription_creator, termination_manager,
+      transmission_manager, expiration_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      pool: A thread pool in which to execute customer code.
+      subscription: A base.Subscription describing the customer's interest in
+        operation values from the other side. May be None if
+        subscription_creator is not None.
+      subscription_creator: A _SubscriptionCreator wrapping the portion of
+        customer code that when called returns the base.Subscription describing
+        the customer's interest in operation values from the other side. May be
+        None if subscription is not None.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+    """
+    self._lock = lock
+    self._pool = pool
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+
+    if subscription is None:
+      self._subscription_creator = subscription_creator
+      self._wrapped_operator = None
+    elif subscription.kind is base.Subscription.Kind.FULL:
+      self._subscription_creator = None
+      self._wrapped_operator = _wrap(subscription.operator.advance)
+    else:
+      # TODO(nathaniel): Support other subscriptions.
+      raise ValueError('Unsupported subscription "%s"!' % subscription.kind)
+    self._pending_initial_metadata = None
+    self._pending_payloads = []
+    self._pending_completion = None
+    self._local_allowance = 1
+    # A nonnegative integer or None, with None indicating that the local
+    # customer is done emitting anyway so there's no need to bother it by
+    # informing it that the remote customer has granted it further permission to
+    # emit.
+    self._remote_allowance = 0
+    self._processing = False
+
+  def _abort_internal_only(self):
+    self._subscription_creator = None
+    self._wrapped_operator = None
+    self._pending_initial_metadata = None
+    self._pending_payloads = None
+    self._pending_completion = None
+
+  def _abort_and_notify(self, outcome):
+    self._abort_internal_only()
+    self._termination_manager.abort(outcome)
+    self._transmission_manager.abort(outcome)
+    self._expiration_manager.terminate()
+
+  def _operator_next(self):
+    """Computes the next step for full-subscription ingestion.
+
+    Returns:
+      An initial_metadata, payload, completion, allowance, continue quintet
+        indicating what operation values (if any) are available to pass into
+        customer code and whether or not there is anything immediately
+        actionable to call customer code to do.
+    """
+    if self._wrapped_operator is None:
+      return None, None, None, None, False
+    else:
+      initial_metadata, payload, completion, allowance, action = [None] * 5
+      if self._pending_initial_metadata is not None:
+        initial_metadata = self._pending_initial_metadata
+        self._pending_initial_metadata = None
+        action = True
+      if self._pending_payloads and 0 < self._local_allowance:
+        payload = self._pending_payloads.pop(0)
+        self._local_allowance -= 1
+        action = True
+      if not self._pending_payloads and self._pending_completion is not None:
+        completion = self._pending_completion
+        self._pending_completion = None
+        action = True
+      if self._remote_allowance is not None and 0 < self._remote_allowance:
+        allowance = self._remote_allowance
+        self._remote_allowance = 0
+        action = True
+      return initial_metadata, payload, completion, allowance, bool(action)
+
+  def _operator_process(
+      self, wrapped_operator, initial_metadata, payload,
+      completion, allowance):
+    while True:
+      advance_outcome = callable_util.call_logging_exceptions(
+          wrapped_operator, _INGESTION_EXCEPTION_LOG_MESSAGE,
+          initial_metadata=initial_metadata, payload=payload,
+          completion=completion, allowance=allowance)
+      if advance_outcome.exception is None:
+        if advance_outcome.return_value:
+          with self._lock:
+            if self._termination_manager.outcome is not None:
+              return
+            if completion is not None:
+              self._termination_manager.ingestion_complete()
+            initial_metadata, payload, completion, allowance, moar = (
+                self._operator_next())
+            if not moar:
+              self._processing = False
+              return
+        else:
+          with self._lock:
+            if self._termination_manager.outcome is None:
+              self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+            return
+      else:
+        with self._lock:
+          if self._termination_manager.outcome is None:
+            self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+          return
+
+  def _operator_post_create(self, subscription):
+    wrapped_operator = _wrap(subscription.operator.advance)
+    with self._lock:
+      if self._termination_manager.outcome is not None:
+        return
+      self._wrapped_operator = wrapped_operator
+      self._subscription_creator = None
+      metadata, payload, completion, allowance, moar = self._operator_next()
+      if not moar:
+        self._processing = False
+        return
+    self._operator_process(
+        wrapped_operator, metadata, payload, completion, allowance)
+
+  def _create(self, subscription_creator, group, name):
+    outcome = callable_util.call_logging_exceptions(
+        subscription_creator.create, _CREATE_SUBSCRIPTION_EXCEPTION_LOG_MESSAGE,
+        group, name)
+    if outcome.return_value is None:
+      with self._lock:
+        if self._termination_manager.outcome is None:
+          self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+    elif outcome.return_value.abandoned:
+      with self._lock:
+        if self._termination_manager.outcome is None:
+          self._abort_and_notify(base.Outcome.LOCAL_FAILURE)
+    elif outcome.return_value.remote_error:
+      with self._lock:
+        if self._termination_manager.outcome is None:
+          self._abort_and_notify(base.Outcome.REMOTE_FAILURE)
+    elif outcome.return_value.subscription.kind is base.Subscription.Kind.FULL:
+      self._operator_post_create(outcome.return_value.subscription)
+    else:
+      # TODO(nathaniel): Support other subscriptions.
+      raise ValueError(
+          'Unsupported "%s"!' % outcome.return_value.subscription.kind)
+
+  def _store_advance(self, initial_metadata, payload, completion, allowance):
+    if initial_metadata is not None:
+      self._pending_initial_metadata = initial_metadata
+    if payload is not None:
+      self._pending_payloads.append(payload)
+    if completion is not None:
+      self._pending_completion = completion
+    if allowance is not None and self._remote_allowance is not None:
+      self._remote_allowance += allowance
+
+  def _operator_advance(self, initial_metadata, payload, completion, allowance):
+    if self._processing:
+      self._store_advance(initial_metadata, payload, completion, allowance)
+    else:
+      action = False
+      if initial_metadata is not None:
+        action = True
+      if payload is not None:
+        if 0 < self._local_allowance:
+          self._local_allowance -= 1
+          action = True
+        else:
+          self._pending_payloads.append(payload)
+          payload = False
+      if completion is not None:
+        if self._pending_payloads:
+          self._pending_completion = completion
+        else:
+          action = True
+      if allowance is not None and self._remote_allowance is not None:
+        allowance += self._remote_allowance
+        self._remote_allowance = 0
+        action = True
+      if action:
+        self._pool.submit(
+            callable_util.with_exceptions_logged(
+                self._operator_process, _constants.INTERNAL_ERROR_LOG_MESSAGE),
+            self._wrapped_operator, initial_metadata, payload, completion,
+            allowance)
+
+  def set_group_and_method(self, group, method):
+    """See _interfaces.IngestionManager.set_group_and_method for spec."""
+    if self._subscription_creator is not None and not self._processing:
+      self._pool.submit(
+          callable_util.with_exceptions_logged(
+              self._create, _constants.INTERNAL_ERROR_LOG_MESSAGE),
+          self._subscription_creator, group, method)
+      self._processing = True
+
+  def add_local_allowance(self, allowance):
+    """See _interfaces.IngestionManager.add_local_allowance for spec."""
+    if any((self._subscription_creator, self._wrapped_operator,)):
+      self._local_allowance += allowance
+      if not self._processing:
+        initial_metadata, payload, completion, allowance, moar = (
+            self._operator_next())
+        if moar:
+          self._pool.submit(
+              callable_util.with_exceptions_logged(
+                  self._operator_process,
+                  _constants.INTERNAL_ERROR_LOG_MESSAGE),
+              initial_metadata, payload, completion, allowance)
+
+  def local_emissions_done(self):
+    self._remote_allowance = None
+
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """See _interfaces.IngestionManager.advance for specification."""
+    if self._subscription_creator is not None:
+      self._store_advance(initial_metadata, payload, completion, allowance)
+    elif self._wrapped_operator is not None:
+      self._operator_advance(initial_metadata, payload, completion, allowance)
+
+
+def invocation_ingestion_manager(
+    subscription, lock, pool, termination_manager, transmission_manager,
+    expiration_manager):
+  """Creates an IngestionManager appropriate for invocation-side use.
+
+  Args:
+    subscription: A base.Subscription indicating the customer's interest in the
+      data and results from the service-side of the operation.
+    lock: The operation-wide lock.
+    pool: A thread pool in which to execute customer code.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+    expiration_manager: The _interfaces.ExpirationManager for the operation.
+
+  Returns:
+    An IngestionManager appropriate for invocation-side use.
+  """
+  return _IngestionManager(
+      lock, pool, subscription, None, termination_manager, transmission_manager,
+      expiration_manager)
+
+
+def service_ingestion_manager(
+    servicer, operation_context, output_operator, lock, pool,
+    termination_manager, transmission_manager, expiration_manager):
+  """Creates an IngestionManager appropriate for service-side use.
+
+  The returned IngestionManager will require its set_group_and_name method to be
+  called before its advance method may be called.
+
+  Args:
+    servicer: A base.Servicer for servicing the operation.
+    operation_context: A base.OperationContext for the operation to be passed to
+      the customer.
+    output_operator: A base.Operator for the operation to be passed to the
+      customer and to be called by the customer to accept operation data output
+      by the customer.
+    lock: The operation-wide lock.
+    pool: A thread pool in which to execute customer code.
+    termination_manager: The _interfaces.TerminationManager for the operation.
+    transmission_manager: The _interfaces.TransmissionManager for the
+      operation.
+    expiration_manager: The _interfaces.ExpirationManager for the operation.
+
+  Returns:
+    An IngestionManager appropriate for service-side use.
+  """
+  subscription_creator = _ServiceSubscriptionCreator(
+      servicer, operation_context, output_operator)
+  return _IngestionManager(
+      lock, pool, None, subscription_creator, termination_manager,
+      transmission_manager, expiration_manager)

src/python/grpcio/grpc/framework/core/_interfaces.py

@@ -0,0 +1,308 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Package-internal interfaces."""
+
+import abc
+
+from grpc.framework.interfaces.base import base
+
+
+class TerminationManager(object):
+  """An object responsible for handling the termination of an operation.
+
+  Attributes:
+    outcome: None if the operation is active or a base.Outcome value if it has
+      terminated.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def add_callback(self, callback):
+    """Registers a callback to be called on operation termination.
+
+    If the operation has already terminated the callback will not be called.
+
+    Args:
+      callback: A callable that will be passed an interfaces.Outcome value.
+
+    Returns:
+      None if the operation has not yet terminated and the passed callback will
+        be called when it does, or a base.Outcome value describing the operation
+        termination if the operation has terminated and the callback will not be
+        called as a result of this method call.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def emission_complete(self):
+    """Indicates that emissions from customer code have completed."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def transmission_complete(self):
+    """Indicates that transmissions to the remote end are complete.
+
+    Returns:
+      True if the operation has terminated or False if the operation remains
+        ongoing.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def reception_complete(self):
+    """Indicates that reception from the other side is complete."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def ingestion_complete(self):
+    """Indicates that customer code ingestion of received values is complete."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def expire(self):
+    """Indicates that the operation must abort because it has taken too long."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def abort(self, outcome):
+    """Indicates that the operation must abort for the indicated reason.
+
+    Args:
+      outcome: An interfaces.Outcome indicating operation abortion.
+    """
+    raise NotImplementedError()
+
+
+class TransmissionManager(object):
+  """A manager responsible for transmitting to the other end of an operation."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def kick_off(
+      self, group, method, timeout, initial_metadata, payload, completion,
+      allowance):
+    """Transmits the values associated with operation invocation."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """Accepts values for transmission to the other end of the operation.
+
+    Args:
+      initial_metadata: An initial metadata value to be transmitted to the other
+        side of the operation. May only ever be non-None once.
+      payload: A payload value.
+      completion: A base.Completion value. May only ever be non-None in the last
+        transmission to be made to the other side.
+      allowance: A positive integer communicating the number of additional
+        payloads allowed to be transmitted from the other side to this side of
+        the operation, or None if no additional allowance is being granted in
+        this call.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def timeout(self, timeout):
+    """Accepts for transmission to the other side a new timeout value.
+
+    Args:
+      timeout: A positive float used as the new timeout value for the operation
+        to be transmitted to the other side.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def allowance(self, allowance):
+    """Indicates to this manager that the remote customer is allowing payloads.
+
+    Args:
+      allowance: A positive integer indicating the number of additional payloads
+        the remote customer is allowing to be transmitted from this side of the
+        operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def remote_complete(self):
+    """Indicates to this manager that data from the remote side is complete."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def abort(self, outcome):
+    """Indicates that the operation has aborted.
+
+    Args:
+      outcome: An interfaces.Outcome for the operation. If None, indicates that
+        the operation abortion should not be communicated to the other side of
+        the operation.
+    """
+    raise NotImplementedError()
+
+
+class ExpirationManager(object):
+  """A manager responsible for aborting the operation if it runs out of time."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def change_timeout(self, timeout):
+    """Changes the timeout allotted for the operation.
+
+    Operation duration is always measure from the beginning of the operation;
+    calling this method changes the operation's allotted time to timeout total
+    seconds, not timeout seconds from the time of this method call.
+
+    Args:
+      timeout: A length of time in seconds to allow for the operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def deadline(self):
+    """Returns the time until which the operation is allowed to run.
+
+    Returns:
+      The time (seconds since the epoch) at which the operation will expire.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def terminate(self):
+    """Indicates to this manager that the operation has terminated."""
+    raise NotImplementedError()
+
+
+class EmissionManager(base.Operator):
+  """A manager of values emitted by customer code."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def advance(
+      self, initial_metadata=None, payload=None, completion=None,
+      allowance=None):
+    """Accepts a value emitted by customer code.
+
+    This method should only be called by customer code.
+
+    Args:
+      initial_metadata: An initial metadata value emitted by the local customer
+        to be sent to the other side of the operation.
+      payload: A payload value emitted by the local customer to be sent to the
+        other side of the operation.
+      completion: A Completion value emitted by the local customer to be sent to
+        the other side of the operation.
+      allowance: A positive integer indicating an additional number of payloads
+        that the local customer is willing to accept from the other side of the
+        operation.
+    """
+    raise NotImplementedError()
+
+
+class IngestionManager(object):
+  """A manager responsible for executing customer code.
+
+  This name of this manager comes from its responsibility to pass successive
+  values from the other side of the operation into the code of the local
+  customer.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def set_group_and_method(self, group, method):
+    """Communicates to this IngestionManager the operation group and method.
+
+    Args:
+      group: The group identifier of the operation.
+      method: The method identifier of the operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def add_local_allowance(self, allowance):
+    """Communicates to this IngestionManager that more payloads may be ingested.
+
+    Args:
+      allowance: A positive integer indicating an additional number of payloads
+        that the local customer is willing to ingest.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def local_emissions_done(self):
+    """Indicates to this manager that local emissions are done."""
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """Advances the operation by passing values to the local customer."""
+    raise NotImplementedError()
+
+
+class ReceptionManager(object):
+  """A manager responsible for receiving tickets from the other end."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def receive_ticket(self, ticket):
+    """Handle a ticket from the other side of the operation.
+
+    Args:
+      ticket: An interfaces.BackToFrontTicket or interfaces.FrontToBackTicket
+        appropriate to this end of the operation and this object.
+    """
+    raise NotImplementedError()
+
+
+class Operation(object):
+  """An ongoing operation.
+
+  Attributes:
+    context: A base.OperationContext object for the operation.
+    operator: A base.Operator object for the operation for use by the customer
+      of the operation.
+  """
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def handle_ticket(self, ticket):
+    """Handle a ticket from the other side of the operation.
+
+    Args:
+      ticket: A links.Ticket from the other side of the operation.
+    """
+    raise NotImplementedError()
+
+  @abc.abstractmethod
+  def abort(self, outcome):
+    """Aborts the operation.
+
+    Args:
+      outcome: A base.Outcome value indicating operation abortion.
+    """
+    raise NotImplementedError()

src/python/grpcio/grpc/framework/core/_operation.py

@@ -0,0 +1,192 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Implementation of operations."""
+
+import threading
+
+# _utilities is referenced from specification in this module.
+from grpc.framework.core import _context
+from grpc.framework.core import _emission
+from grpc.framework.core import _expiration
+from grpc.framework.core import _ingestion
+from grpc.framework.core import _interfaces
+from grpc.framework.core import _reception
+from grpc.framework.core import _termination
+from grpc.framework.core import _transmission
+from grpc.framework.core import _utilities  # pylint: disable=unused-import
+
+
+class _EasyOperation(_interfaces.Operation):
+  """A trivial implementation of interfaces.Operation."""
+
+  def __init__(
+      self, lock, termination_manager, transmission_manager, expiration_manager,
+      context, operator, reception_manager):
+    """Constructor.
+
+    Args:
+      lock: The operation-wide lock.
+      termination_manager: The _interfaces.TerminationManager for the operation.
+      transmission_manager: The _interfaces.TransmissionManager for the
+        operation.
+      expiration_manager: The _interfaces.ExpirationManager for the operation.
+      context: A base.OperationContext for use by the customer during the
+        operation.
+      operator: A base.Operator for use by the customer during the operation.
+      reception_manager: The _interfaces.ReceptionManager for the operation.
+    """
+    self._lock = lock
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+    self._reception_manager = reception_manager
+
+    self.context = context
+    self.operator = operator
+
+  def handle_ticket(self, ticket):
+    with self._lock:
+      self._reception_manager.receive_ticket(ticket)
+
+  def abort(self, outcome):
+    with self._lock:
+      if self._termination_manager.outcome is None:
+        self._termination_manager.abort(outcome)
+        self._transmission_manager.abort(outcome)
+        self._expiration_manager.terminate()
+
+
+def invocation_operate(
+    operation_id, group, method, subscription, timeout, initial_metadata,
+    payload, completion, ticket_sink, termination_action, pool):
+  """Constructs objects necessary for front-side operation management.
+
+  Args:
+    operation_id: An object identifying the operation.
+    group: The group identifier of the operation.
+    method: The method identifier of the operation.
+    subscription: A base.Subscription describing the customer's interest in the
+      results of the operation.
+    timeout: A length of time in seconds to allow for the operation.
+    initial_metadata: An initial metadata value to be sent to the other side of
+      the operation. May be None if the initial metadata will be passed later or
+      if there will be no initial metadata passed at all.
+    payload: The first payload value to be transmitted to the other side. May be
+      None if there is no such value or if the customer chose not to pass it at
+      operation invocation.
+    completion: A base.Completion value indicating the end of values passed to
+      the other side of the operation.
+    ticket_sink: A callable that accepts links.Tickets and delivers them to the
+      other side of the operation.
+    termination_action: A callable that accepts the outcome of the operation as
+      a base.Outcome value to be called on operation completion.
+    pool: A thread pool with which to do the work of the operation.
+
+  Returns:
+    An _interfaces.Operation for the operation.
+  """
+  lock = threading.Lock()
+  with lock:
+    termination_manager = _termination.invocation_termination_manager(
+        termination_action, pool)
+    transmission_manager = _transmission.TransmissionManager(
+        operation_id, ticket_sink, lock, pool, termination_manager)
+    expiration_manager = _expiration.invocation_expiration_manager(
+        timeout, lock, termination_manager, transmission_manager)
+    operation_context = _context.OperationContext(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    emission_manager = _emission.EmissionManager(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    ingestion_manager = _ingestion.invocation_ingestion_manager(
+        subscription, lock, pool, termination_manager, transmission_manager,
+        expiration_manager)
+    reception_manager = _reception.ReceptionManager(
+        termination_manager, transmission_manager, expiration_manager,
+        ingestion_manager)
+
+    termination_manager.set_expiration_manager(expiration_manager)
+    transmission_manager.set_expiration_manager(expiration_manager)
+    emission_manager.set_ingestion_manager(ingestion_manager)
+
+    transmission_manager.kick_off(
+        group, method, timeout, initial_metadata, payload, completion, None)
+
+  return _EasyOperation(
+      lock, termination_manager, transmission_manager, expiration_manager,
+      operation_context, emission_manager, reception_manager)
+
+
+def service_operate(
+    servicer_package, ticket, ticket_sink, termination_action, pool):
+  """Constructs an Operation for service of an operation.
+
+  Args:
+    servicer_package: A _utilities.ServicerPackage to be used servicing the
+      operation.
+    ticket: The first links.Ticket received for the operation.
+    ticket_sink: A callable that accepts links.Tickets and delivers them to the
+      other side of the operation.
+    termination_action: A callable that accepts the outcome of the operation as
+      a base.Outcome value to be called on operation completion.
+    pool: A thread pool with which to do the work of the operation.
+
+  Returns:
+    An _interfaces.Operation for the operation.
+  """
+  lock = threading.Lock()
+  with lock:
+    termination_manager = _termination.service_termination_manager(
+        termination_action, pool)
+    transmission_manager = _transmission.TransmissionManager(
+        ticket.operation_id, ticket_sink, lock, pool, termination_manager)
+    expiration_manager = _expiration.service_expiration_manager(
+        ticket.timeout, servicer_package.default_timeout,
+        servicer_package.maximum_timeout, lock, termination_manager,
+        transmission_manager)
+    operation_context = _context.OperationContext(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    emission_manager = _emission.EmissionManager(
+        lock, termination_manager, transmission_manager, expiration_manager)
+    ingestion_manager = _ingestion.service_ingestion_manager(
+        servicer_package.servicer, operation_context, emission_manager, lock,
+        pool, termination_manager, transmission_manager, expiration_manager)
+    reception_manager = _reception.ReceptionManager(
+        termination_manager, transmission_manager, expiration_manager,
+        ingestion_manager)
+
+    termination_manager.set_expiration_manager(expiration_manager)
+    transmission_manager.set_expiration_manager(expiration_manager)
+    emission_manager.set_ingestion_manager(ingestion_manager)
+
+    reception_manager.receive_ticket(ticket)
+
+  return _EasyOperation(
+      lock, termination_manager, transmission_manager, expiration_manager,
+      operation_context, emission_manager, reception_manager)

src/python/grpcio/grpc/framework/core/_reception.py

@@ -0,0 +1,137 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for ticket reception."""
+
+from grpc.framework.core import _interfaces
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.base import utilities
+from grpc.framework.interfaces.links import links
+
+_REMOTE_TICKET_TERMINATION_TO_LOCAL_OUTCOME = {
+    links.Ticket.Termination.CANCELLATION: base.Outcome.CANCELLED,
+    links.Ticket.Termination.EXPIRATION: base.Outcome.EXPIRED,
+    links.Ticket.Termination.SHUTDOWN: base.Outcome.REMOTE_SHUTDOWN,
+    links.Ticket.Termination.RECEPTION_FAILURE: base.Outcome.RECEPTION_FAILURE,
+    links.Ticket.Termination.TRANSMISSION_FAILURE:
+        base.Outcome.TRANSMISSION_FAILURE,
+    links.Ticket.Termination.LOCAL_FAILURE: base.Outcome.REMOTE_FAILURE,
+}
+
+
+class ReceptionManager(_interfaces.ReceptionManager):
+  """A ReceptionManager based around a _Receiver passed to it."""
+
+  def __init__(
+      self, termination_manager, transmission_manager, expiration_manager,
+      ingestion_manager):
+    """Constructor.
+
+    Args:
+      termination_manager: The operation's _interfaces.TerminationManager.
+      transmission_manager: The operation's _interfaces.TransmissionManager.
+      expiration_manager: The operation's _interfaces.ExpirationManager.
+      ingestion_manager: The operation's _interfaces.IngestionManager.
+    """
+    self._termination_manager = termination_manager
+    self._transmission_manager = transmission_manager
+    self._expiration_manager = expiration_manager
+    self._ingestion_manager = ingestion_manager
+
+    self._lowest_unseen_sequence_number = 0
+    self._out_of_sequence_tickets = {}
+    self._aborted = False
+
+  def _abort(self, outcome):
+    self._aborted = True
+    self._termination_manager.abort(outcome)
+    self._transmission_manager.abort(outcome)
+    self._expiration_manager.terminate()
+
+  def _sequence_failure(self, ticket):
+    """Determines a just-arrived ticket's sequential legitimacy.
+
+    Args:
+      ticket: A just-arrived ticket.
+
+    Returns:
+      True if the ticket is sequentially legitimate; False otherwise.
+    """
+    if ticket.sequence_number < self._lowest_unseen_sequence_number:
+      return True
+    elif ticket.sequence_number in self._out_of_sequence_tickets:
+      return True
+    else:
+      return False
+
+  def _process_one(self, ticket):
+    if ticket.sequence_number == 0:
+      self._ingestion_manager.set_group_and_method(ticket.group, ticket.method)
+    if ticket.timeout is not None:
+      self._expiration_manager.change_timeout(ticket.timeout)
+    if ticket.termination is None:
+      completion = None
+    else:
+      completion = utilities.completion(
+          ticket.terminal_metadata, ticket.code, ticket.message)
+    self._ingestion_manager.advance(
+        ticket.initial_metadata, ticket.payload, completion, ticket.allowance)
+    if ticket.allowance is not None:
+      self._transmission_manager.allowance(ticket.allowance)
+
+  def _process(self, ticket):
+    """Process those tickets ready to be processed.
+
+    Args:
+      ticket: A just-arrived ticket the sequence number of which matches this
+        _ReceptionManager's _lowest_unseen_sequence_number field.
+    """
+    while True:
+      self._process_one(ticket)
+      next_ticket = self._out_of_sequence_tickets.pop(
+          ticket.sequence_number + 1, None)
+      if next_ticket is None:
+        self._lowest_unseen_sequence_number = ticket.sequence_number + 1
+        return
+      else:
+        ticket = next_ticket
+
+  def receive_ticket(self, ticket):
+    """See _interfaces.ReceptionManager.receive_ticket for specification."""
+    if self._aborted:
+      return
+    elif self._sequence_failure(ticket):
+      self._abort(base.Outcome.RECEPTION_FAILURE)
+    elif ticket.termination not in (None, links.Ticket.Termination.COMPLETION):
+      outcome = _REMOTE_TICKET_TERMINATION_TO_LOCAL_OUTCOME[ticket.termination]
+      self._abort(outcome)
+    elif ticket.sequence_number == self._lowest_unseen_sequence_number:
+      self._process(ticket)
+    else:
+      self._out_of_sequence_tickets[ticket.sequence_number] = ticket

src/python/grpcio/grpc/framework/core/_termination.py

@@ -0,0 +1,212 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for operation termination."""
+
+import abc
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+
+
+def _invocation_completion_predicate(
+    unused_emission_complete, unused_transmission_complete,
+    unused_reception_complete, ingestion_complete):
+  return ingestion_complete
+
+
+def _service_completion_predicate(
+    unused_emission_complete, transmission_complete, unused_reception_complete,
+    unused_ingestion_complete):
+  return transmission_complete
+
+
+class TerminationManager(_interfaces.TerminationManager):
+  """A _interfaces.TransmissionManager on which another manager may be set."""
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def set_expiration_manager(self, expiration_manager):
+    """Sets the expiration manager with which this manager will interact.
+
+    Args:
+      expiration_manager: The _interfaces.ExpirationManager associated with the
+        current operation.
+    """
+    raise NotImplementedError()
+
+
+class _TerminationManager(TerminationManager):
+  """An implementation of TerminationManager."""
+
+  def __init__(self, predicate, action, pool):
+    """Constructor.
+
+    Args:
+      predicate: One of _invocation_completion_predicate or
+        _service_completion_predicate to be used to determine when the operation
+        has completed.
+      action: A behavior to pass the operation outcome on operation termination.
+      pool: A thread pool.
+    """
+    self._predicate = predicate
+    self._action = action
+    self._pool = pool
+    self._expiration_manager = None
+
+    self.outcome = None
+    self._callbacks = []
+
+    self._emission_complete = False
+    self._transmission_complete = False
+    self._reception_complete = False
+    self._ingestion_complete = False
+
+  def set_expiration_manager(self, expiration_manager):
+    self._expiration_manager = expiration_manager
+
+  def _terminate_internal_only(self, outcome):
+    """Terminates the operation.
+
+    Args:
+      outcome: A base.Outcome describing the outcome of the operation.
+    """
+    self.outcome = outcome
+    callbacks = list(self._callbacks)
+    self._callbacks = None
+
+    act = callable_util.with_exceptions_logged(
+        self._action, _constants.INTERNAL_ERROR_LOG_MESSAGE)
+
+    if outcome is base.Outcome.LOCAL_FAILURE:
+      self._pool.submit(act, outcome)
+    else:
+      def call_callbacks_and_act(callbacks, outcome):
+        for callback in callbacks:
+          callback_outcome = callable_util.call_logging_exceptions(
+              callback, _constants.TERMINATION_CALLBACK_EXCEPTION_LOG_MESSAGE,
+              outcome)
+          if callback_outcome.exception is not None:
+            outcome = base.Outcome.LOCAL_FAILURE
+            break
+        act(outcome)
+
+      self._pool.submit(
+          callable_util.with_exceptions_logged(
+              call_callbacks_and_act, _constants.INTERNAL_ERROR_LOG_MESSAGE),
+          callbacks, outcome)
+
+  def _terminate_and_notify(self, outcome):
+    self._terminate_internal_only(outcome)
+    self._expiration_manager.terminate()
+
+  def _perhaps_complete(self):
+    if self._predicate(
+        self._emission_complete, self._transmission_complete,
+        self._reception_complete, self._ingestion_complete):
+      self._terminate_and_notify(base.Outcome.COMPLETED)
+      return True
+    else:
+      return False
+
+  def is_active(self):
+    """See _interfaces.TerminationManager.is_active for specification."""
+    return self.outcome is None
+
+  def add_callback(self, callback):
+    """See _interfaces.TerminationManager.add_callback for specification."""
+    if self.outcome is None:
+      self._callbacks.append(callback)
+      return None
+    else:
+      return self.outcome
+
+  def emission_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._emission_complete = True
+      self._perhaps_complete()
+
+  def transmission_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._transmission_complete = True
+      return self._perhaps_complete()
+    else:
+      return False
+
+  def reception_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._reception_complete = True
+      self._perhaps_complete()
+
+  def ingestion_complete(self):
+    """See superclass method for specification."""
+    if self.outcome is None:
+      self._ingestion_complete = True
+      self._perhaps_complete()
+
+  def expire(self):
+    """See _interfaces.TerminationManager.expire for specification."""
+    self._terminate_internal_only(base.Outcome.EXPIRED)
+
+  def abort(self, outcome):
+    """See _interfaces.TerminationManager.abort for specification."""
+    self._terminate_and_notify(outcome)
+
+
+def invocation_termination_manager(action, pool):
+  """Creates a TerminationManager appropriate for invocation-side use.
+
+  Args:
+    action: An action to call on operation termination.
+    pool: A thread pool in which to execute the passed action and any
+      termination callbacks that are registered during the operation.
+
+  Returns:
+    A TerminationManager appropriate for invocation-side use.
+  """
+  return _TerminationManager(_invocation_completion_predicate, action, pool)
+
+
+def service_termination_manager(action, pool):
+  """Creates a TerminationManager appropriate for service-side use.
+
+  Args:
+    action: An action to call on operation termination.
+    pool: A thread pool in which to execute the passed action and any
+      termination callbacks that are registered during the operation.
+
+  Returns:
+    A TerminationManager appropriate for service-side use.
+  """
+  return _TerminationManager(_service_completion_predicate, action, pool)

src/python/grpcio/grpc/framework/core/_transmission.py

@@ -0,0 +1,294 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""State and behavior for ticket transmission during an operation."""
+
+from grpc.framework.core import _constants
+from grpc.framework.core import _interfaces
+from grpc.framework.foundation import callable_util
+from grpc.framework.interfaces.base import base
+from grpc.framework.interfaces.links import links
+
+_TRANSMISSION_EXCEPTION_LOG_MESSAGE = 'Exception during transmission!'
+
+
+def _explode_completion(completion):
+  if completion is None:
+    return None, None, None, None
+  else:
+    return (
+        completion.terminal_metadata, completion.code, completion.message,
+        links.Ticket.Termination.COMPLETION)
+
+
+class TransmissionManager(_interfaces.TransmissionManager):
+  """An _interfaces.TransmissionManager that sends links.Tickets."""
+
+  def __init__(
+      self, operation_id, ticket_sink, lock, pool, termination_manager):
+    """Constructor.
+
+    Args:
+      operation_id: The operation's ID.
+      ticket_sink: A callable that accepts tickets and sends them to the other
+        side of the operation.
+      lock: The operation-servicing-wide lock object.
+      pool: A thread pool in which the work of transmitting tickets will be
+        performed.
+      termination_manager: The _interfaces.TerminationManager associated with
+        this operation.
+    """
+    self._lock = lock
+    self._pool = pool
+    self._ticket_sink = ticket_sink
+    self._operation_id = operation_id
+    self._termination_manager = termination_manager
+    self._expiration_manager = None
+
+    self._lowest_unused_sequence_number = 0
+    self._remote_allowance = 1
+    self._remote_complete = False
+    self._timeout = None
+    self._local_allowance = 0
+    self._initial_metadata = None
+    self._payloads = []
+    self._completion = None
+    self._aborted = False
+    self._abortion_outcome = None
+    self._transmitting = False
+
+  def set_expiration_manager(self, expiration_manager):
+    """Sets the ExpirationManager with which this manager will cooperate."""
+    self._expiration_manager = expiration_manager
+
+  def _next_ticket(self):
+    """Creates the next ticket to be transmitted.
+
+    Returns:
+      A links.Ticket to be sent to the other side of the operation or None if
+        there is nothing to be sent at this time.
+    """
+    if self._aborted:
+      if self._abortion_outcome is None:
+        return None
+      else:
+        termination = _constants.ABORTION_OUTCOME_TO_TICKET_TERMINATION[
+            self._abortion_outcome]
+        if termination is None:
+          return None
+        else:
+          self._abortion_outcome = None
+          return links.Ticket(
+              self._operation_id, self._lowest_unused_sequence_number, None,
+              None, None, None, None, None, None, None, None, None,
+              termination)
+
+    action = False
+    # TODO(nathaniel): Support other subscriptions.
+    local_subscription = links.Ticket.Subscription.FULL
+    timeout = self._timeout
+    if timeout is not None:
+      self._timeout = None
+      action = True
+    if self._local_allowance <= 0:
+      allowance = None
+    else:
+      allowance = self._local_allowance
+      self._local_allowance = 0
+      action = True
+    initial_metadata = self._initial_metadata
+    if initial_metadata is not None:
+      self._initial_metadata = None
+      action = True
+    if not self._payloads or self._remote_allowance <= 0:
+      payload = None
+    else:
+      payload = self._payloads.pop(0)
+      self._remote_allowance -= 1
+      action = True
+    if self._completion is None or self._payloads:
+      terminal_metadata, code, message, termination = None, None, None, None
+    else:
+      terminal_metadata, code, message, termination = _explode_completion(
+          self._completion)
+      self._completion = None
+      action = True
+
+    if action:
+      ticket = links.Ticket(
+          self._operation_id, self._lowest_unused_sequence_number, None, None,
+          local_subscription, timeout, allowance, initial_metadata, payload,
+          terminal_metadata, code, message, termination)
+      self._lowest_unused_sequence_number += 1
+      return ticket
+    else:
+      return None
+
+  def _transmit(self, ticket):
+    """Commences the transmission loop sending tickets.
+
+    Args:
+      ticket: A links.Ticket to be sent to the other side of the operation.
+    """
+    def transmit(ticket):
+      while True:
+        transmission_outcome = callable_util.call_logging_exceptions(
+            self._ticket_sink, _TRANSMISSION_EXCEPTION_LOG_MESSAGE, ticket)
+        if transmission_outcome.exception is None:
+          with self._lock:
+            if ticket.termination is links.Ticket.Termination.COMPLETION:
+              self._termination_manager.transmission_complete()
+            ticket = self._next_ticket()
+            if ticket is None:
+              self._transmitting = False
+              return
+        else:
+          with self._lock:
+            if self._termination_manager.outcome is None:
+              self._termination_manager.abort(base.Outcome.TRANSMISSION_FAILURE)
+              self._expiration_manager.terminate()
+            return
+
+    self._pool.submit(callable_util.with_exceptions_logged(
+        transmit, _constants.INTERNAL_ERROR_LOG_MESSAGE), ticket)
+    self._transmitting = True
+
+  def kick_off(
+      self, group, method, timeout, initial_metadata, payload, completion,
+      allowance):
+    """See _interfaces.TransmissionManager.kickoff for specification."""
+    # TODO(nathaniel): Support other subscriptions.
+    subscription = links.Ticket.Subscription.FULL
+    terminal_metadata, code, message, termination = _explode_completion(
+        completion)
+    self._remote_allowance = 1 if payload is None else 0
+    ticket = links.Ticket(
+        self._operation_id, 0, group, method, subscription, timeout, allowance,
+        initial_metadata, payload, terminal_metadata, code, message,
+        termination)
+    self._lowest_unused_sequence_number = 1
+    self._transmit(ticket)
+
+  def advance(self, initial_metadata, payload, completion, allowance):
+    """See _interfaces.TransmissionManager.advance for specification."""
+    effective_initial_metadata = initial_metadata
+    effective_payload = payload
+    effective_completion = completion
+    if allowance is not None and not self._remote_complete:
+      effective_allowance = allowance
+    else:
+      effective_allowance = None
+    if self._transmitting:
+      if effective_initial_metadata is not None:
+        self._initial_metadata = effective_initial_metadata
+      if effective_payload is not None:
+        self._payloads.append(effective_payload)
+      if effective_completion is not None:
+        self._completion = effective_completion
+      if effective_allowance is not None:
+        self._local_allowance += effective_allowance
+    else:
+      if effective_payload is not None:
+        if 0 < self._remote_allowance:
+          ticket_payload = effective_payload
+          self._remote_allowance -= 1
+        else:
+          self._payloads.append(effective_payload)
+          ticket_payload = None
+      else:
+        ticket_payload = None
+      if effective_completion is not None and not self._payloads:
+        ticket_completion = effective_completion
+      else:
+        self._completion = effective_completion
+        ticket_completion = None
+      if any(
+          (effective_initial_metadata, ticket_payload, ticket_completion,
+           effective_allowance)):
+        terminal_metadata, code, message, termination = _explode_completion(
+            completion)
+        ticket = links.Ticket(
+            self._operation_id, self._lowest_unused_sequence_number, None, None,
+            None, None, allowance, effective_initial_metadata, ticket_payload,
+            terminal_metadata, code, message, termination)
+        self._lowest_unused_sequence_number += 1
+        self._transmit(ticket)
+
+  def timeout(self, timeout):
+    """See _interfaces.TransmissionManager.timeout for specification."""
+    if self._transmitting:
+      self._timeout = timeout
+    else:
+      ticket = links.Ticket(
+          self._operation_id, self._lowest_unused_sequence_number, None, None,
+          None, timeout, None, None, None, None, None, None, None)
+      self._lowest_unused_sequence_number += 1
+      self._transmit(ticket)
+
+  def allowance(self, allowance):
+    """See _interfaces.TransmissionManager.allowance for specification."""
+    if self._transmitting or not self._payloads:
+      self._remote_allowance += allowance
+    else:
+      self._remote_allowance += allowance - 1
+      payload = self._payloads.pop(0)
+      if self._payloads:
+        completion = None
+      else:
+        completion = self._completion
+        self._completion = None
+      terminal_metadata, code, message, termination = _explode_completion(
+          completion)
+      ticket = links.Ticket(
+          self._operation_id, self._lowest_unused_sequence_number, None, None,
+          None, None, None, None, payload, terminal_metadata, code, message,
+          termination)
+      self._lowest_unused_sequence_number += 1
+      self._transmit(ticket)
+
+  def remote_complete(self):
+    """See _interfaces.TransmissionManager.remote_complete for specification."""
+    self._remote_complete = True
+    self._local_allowance = 0
+
+  def abort(self, outcome):
+    """See _interfaces.TransmissionManager.abort for specification."""
+    if self._transmitting:
+      self._aborted, self._abortion_outcome = True, outcome
+    else:
+      self._aborted = True
+      if outcome is not None:
+        termination = _constants.ABORTION_OUTCOME_TO_TICKET_TERMINATION[
+            outcome]
+        if termination is not None:
+          ticket = links.Ticket(
+              self._operation_id, self._lowest_unused_sequence_number, None,
+              None, None, None, None, None, None, None, None, None,
+              termination)
+          self._transmit(ticket)

src/python/grpcio/grpc/framework/core/_utilities.py

@@ -0,0 +1,46 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Package-internal utilities."""
+
+import collections
+
+
+class ServicerPackage(
+    collections.namedtuple(
+        'ServicerPackage', ('servicer', 'default_timeout', 'maximum_timeout'))):
+  """A trivial bundle class.
+
+  Attributes:
+    servicer: A base.Servicer.
+    default_timeout: A float indicating the length of time in seconds to allow
+      for an operation invoked without a timeout.
+    maximum_timeout: A float indicating the maximum length of time in seconds to
+      allow for an operation.
+  """

src/python/grpcio/grpc/framework/core/implementations.py

@@ -0,0 +1,62 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Entry points into the ticket-exchange-based base layer implementation."""
+
+# base and links are referenced from specification in this module.
+from grpc.framework.core import _end
+from grpc.framework.interfaces.base import base  # pylint: disable=unused-import
+from grpc.framework.interfaces.links import links  # pylint: disable=unused-import
+
+
+def invocation_end_link():
+  """Creates a base.End-links.Link suitable for operation invocation.
+
+  Returns:
+    An object that is both a base.End and a links.Link, that supports operation
+      invocation, and that translates operation invocation into ticket exchange.
+  """
+  return _end.serviceless_end_link()
+
+
+def service_end_link(servicer, default_timeout, maximum_timeout):
+  """Creates a base.End-links.Link suitable for operation service.
+
+  Args:
+    servicer: A base.Servicer for servicing operations.
+    default_timeout: A length of time in seconds to be used as the default
+      time alloted for a single operation.
+    maximum_timeout: A length of time in seconds to be used as the maximum
+      time alloted for a single operation.
+
+  Returns:
+    An object that is both a base.End and a links.Link and that services
+      operations that arrive at it through ticket exchange.
+  """
+  return _end.serviceful_end_link(servicer, default_timeout, maximum_timeout)