Change grpc_handshaker_args to be owned by the handshake manager.

Also clean up hand-off semantics of endpoints.

src/core/ext/transport/chttp2/client/insecure/channel_create.c

@@ -97,6 +97,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   grpc_handshaker_args *args = arg;
   connector *c = args->user_data;
   if (error != GRPC_ERROR_NONE) {
+    grpc_endpoint_destroy(exec_ctx, args->endpoint);
     grpc_channel_args_destroy(args->args);
     gpr_free(args->read_buffer);
   } else {
@@ -107,7 +108,6 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
                                         args->read_buffer);
     c->result->channel_args = args->args;
   }
-  gpr_free(args);
   grpc_closure *notify = c->notify;
   c->notify = NULL;
   grpc_exec_ctx_sched(exec_ctx, notify, GRPC_ERROR_REF(error), NULL);

src/core/ext/transport/chttp2/client/secure/secure_channel_create.c

@@ -135,6 +135,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   connector *c = args->user_data;
   c->tmp_args = args->args;
   if (error != GRPC_ERROR_NONE) {
+    grpc_endpoint_destroy(exec_ctx, args->endpoint);
     gpr_free(args->read_buffer);
     grpc_closure *notify = c->notify;
     c->notify = NULL;
@@ -147,7 +148,6 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
         exec_ctx, c->security_connector, args->endpoint, args->read_buffer,
         c->args.deadline, on_secure_handshake_done, c);
   }
-  gpr_free(args);
 }
 
 static void on_initial_connect_string_sent(grpc_exec_ctx *exec_ctx, void *arg,

src/core/ext/transport/chttp2/server/insecure/server_chttp2.c

@@ -62,7 +62,7 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
     const char *error_str = grpc_error_string(error);
     gpr_log(GPR_ERROR, "Handshaking failed: %s", error_str);
     grpc_error_free_string(error_str);
-    grpc_handshake_manager_shutdown(exec_ctx, state->handshake_mgr);
+    grpc_endpoint_destroy(exec_ctx, args->endpoint);
     gpr_free(args->read_buffer);
   } else {
     // Beware that the call to grpc_create_chttp2_transport() has to happen
@@ -79,7 +79,6 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
   }
   // Clean up.
   grpc_channel_args_destroy(args->args);
-  gpr_free(args);
   grpc_handshake_manager_destroy(exec_ctx, state->handshake_mgr);
   gpr_free(state);
 }

src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c

@@ -123,17 +123,14 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
     const char *error_str = grpc_error_string(error);
     gpr_log(GPR_ERROR, "Handshaking failed: %s", error_str);
     grpc_error_free_string(error_str);
+    grpc_endpoint_destroy(exec_ctx, args->endpoint);
     grpc_channel_args_destroy(args->args);
     gpr_free(args->read_buffer);
-    gpr_free(args);
-    grpc_handshake_manager_shutdown(exec_ctx, connection_state->handshake_mgr);
     grpc_handshake_manager_destroy(exec_ctx, connection_state->handshake_mgr);
     grpc_tcp_server_unref(exec_ctx, connection_state->server_state->tcp);
     gpr_free(connection_state);
     return;
   }
-  grpc_handshake_manager_destroy(exec_ctx, connection_state->handshake_mgr);
-  connection_state->handshake_mgr = NULL;
   // TODO(roth, jboeuf): Convert security connector handshaking to use new
   // handshake API, and then move the code from on_secure_handshake_done()
   // into this function.
@@ -142,7 +139,8 @@ static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
       exec_ctx, connection_state->server_state->sc, connection_state->acceptor,
       args->endpoint, args->read_buffer, connection_state->deadline,
       on_secure_handshake_done, connection_state);
-  gpr_free(args);
+  grpc_handshake_manager_destroy(exec_ctx, connection_state->handshake_mgr);
+  connection_state->handshake_mgr = NULL;
 }
 
 static void on_accept(grpc_exec_ctx *exec_ctx, void *statep, grpc_endpoint *tcp,

src/core/lib/channel/handshaker.c

@@ -88,6 +88,8 @@ struct grpc_handshake_manager {
   // The final callback and user_data to invoke after the last handshaker.
   grpc_closure on_handshake_done;
   void* user_data;
+  // Handshaker args.
+  grpc_handshaker_args args;
 };
 
 grpc_handshake_manager* grpc_handshake_manager_create() {
@@ -205,22 +207,22 @@ void grpc_handshake_manager_do_handshake(
     grpc_iomgr_cb_func on_handshake_done, void* user_data) {
   // Construct handshaker args.  These will be passed through all
   // handshakers and eventually be freed by the on_handshake_done callback.
-  grpc_handshaker_args* args = gpr_malloc(sizeof(*args));
-  args->endpoint = endpoint;
-  args->args = grpc_channel_args_copy(channel_args);
-  args->read_buffer = gpr_malloc(sizeof(*args->read_buffer));
-  grpc_slice_buffer_init(args->read_buffer);
+  mgr->args.endpoint = endpoint;
+  mgr->args.args = grpc_channel_args_copy(channel_args);
+  mgr->args.read_buffer = gpr_malloc(sizeof(*mgr->args.read_buffer));
+  grpc_slice_buffer_init(mgr->args.read_buffer);
   // Initialize state needed for calling handshakers.
   gpr_mu_lock(&mgr->mu);
   GPR_ASSERT(mgr->index == 0);
   mgr->acceptor = acceptor;
-  grpc_closure_init(&mgr->call_next_handshaker, call_next_handshaker, args);
-  grpc_closure_init(&mgr->on_handshake_done, on_handshake_done, args);
+  grpc_closure_init(&mgr->call_next_handshaker, call_next_handshaker,
+                    &mgr->args);
+  grpc_closure_init(&mgr->on_handshake_done, on_handshake_done, &mgr->args);
   // While chaining between handshakers, we use args->user_data to
   // store a pointer to the handshake manager.  This will be
   // changed to point to the caller-supplied user_data before calling
   // the on_handshake_done callback.
-  args->user_data = mgr;
+  mgr->args.user_data = mgr;
   mgr->user_data = user_data;
   // Start deadline timer, which owns a ref.
   gpr_ref(&mgr->refs);
@@ -229,6 +231,6 @@ void grpc_handshake_manager_do_handshake(
                   on_timeout, mgr, gpr_now(GPR_CLOCK_MONOTONIC));
   // Start first handshaker, which also owns a ref.
   gpr_ref(&mgr->refs);
-  call_next_handshaker_locked(exec_ctx, mgr, args, GRPC_ERROR_NONE);
+  call_next_handshaker_locked(exec_ctx, mgr, &mgr->args, GRPC_ERROR_NONE);
   gpr_mu_unlock(&mgr->mu);
 }

src/core/lib/channel/handshaker.h

@@ -55,7 +55,14 @@
 typedef struct grpc_handshaker grpc_handshaker;
 
 /// Arguments passed through handshakers and to the on_handshake_done callback.
-/// All data members are owned by the struct.
+///
+/// For handshakers, all members are input/output parameters; for
+/// example, a handshaker may read from \a endpoint and then later
+/// replace it with a wrapped endpoint.  Similarly, a handshaker may
+/// modify \a args.
+///
+/// For the on_handshake_done callback, all members are input arguments,
+/// which the callback takes ownership of.
 typedef struct {
   grpc_endpoint* endpoint;
   grpc_channel_args* args;
@@ -117,11 +124,17 @@ void grpc_handshake_manager_shutdown(grpc_exec_ctx* exec_ctx,
                                      grpc_handshake_manager* mgr);
 
 /// Invokes handshakers in the order they were added.
+/// Takes ownership of \a endpoint, and then passes that ownership to
+/// the \a on_handshake_done callback.
 /// Does NOT take ownership of \a args.  Instead, makes a copy before
 /// invoking the first handshaker.
 /// \a acceptor will be NULL for client-side handshakers.
-/// When done, invokes \a on_handshake_done with an argument of a
-/// grpc_handshaker_args object, which the callback takes ownership of.
+///
+/// When done, invokes \a on_handshake_done with a grpc_handshaker_args
+/// object as its argument.  If the callback is invoked with error !=
+/// GRPC_ERROR_NONE, then handshaking failed and the resulting endpoint
+/// will have already been shut down (although the caller will still be
+/// responsible for destroying it).
 void grpc_handshake_manager_do_handshake(
     grpc_exec_ctx* exec_ctx, grpc_handshake_manager* mgr,
     grpc_endpoint* endpoint, const grpc_channel_args* channel_args,