[EventEngine] Fix the shims for iOS (#32363)

The shims assumed that all platforms with Posix socket support would use
the PosixEventEngine. This is not the case for iOS.




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src/core/lib/event_engine/shim.cc

@@ -25,7 +25,7 @@ namespace experimental {
 bool UseEventEngineClient() {
 // TODO(hork, eryu): Adjust the ifdefs accordingly when event engines become
 // available for other platforms.
-#ifdef GRPC_POSIX_SOCKET_TCP
+#if defined(GRPC_POSIX_SOCKET_TCP) and !defined(GRPC_CFSTREAM)
   return grpc_core::IsEventEngineClientEnabled();
 #else
   return false;
@@ -35,12 +35,20 @@ bool UseEventEngineClient() {
 bool UseEventEngineListener() {
 // TODO(hork, eryu): Adjust the ifdefs accordingly when event engines become
 // available for other platforms.
-#ifdef GRPC_POSIX_SOCKET_TCP
+#if defined(GRPC_POSIX_SOCKET_TCP) and !defined(GRPC_CFSTREAM)
   return grpc_core::IsEventEngineListenerEnabled();
 #else
   return false;
 #endif
 }
 
+bool EventEngineSupportsFd() {
+#if defined(GRPC_POSIX_SOCKET_TCP) and !defined(GRPC_CFSTREAM)
+  return true;
+#else
+  return false;
+#endif
+}
+
 }  // namespace experimental
 }  // namespace grpc_event_engine

src/core/lib/event_engine/shim.h

@@ -14,6 +14,8 @@
 #ifndef GRPC_SRC_CORE_LIB_EVENT_ENGINE_SHIM_H
 #define GRPC_SRC_CORE_LIB_EVENT_ENGINE_SHIM_H
 
+// Platform-specific configuration for use of the EventEngine shims.
+
 #include <grpc/support/port_platform.h>
 
 namespace grpc_event_engine {
@@ -23,6 +25,8 @@ bool UseEventEngineClient();
 
 bool UseEventEngineListener();
 
+bool EventEngineSupportsFd();
+
 }  // namespace experimental
 }  // namespace grpc_event_engine
 

src/core/lib/iomgr/event_engine_shims/endpoint.cc

@@ -29,6 +29,7 @@
 #include <grpc/support/time.h>
 
 #include "src/core/lib/event_engine/posix.h"
+#include "src/core/lib/event_engine/shim.h"
 #include "src/core/lib/event_engine/tcp_socket_utils.h"
 #include "src/core/lib/event_engine/trace.h"
 #include "src/core/lib/gpr/string.h"
@@ -128,12 +129,10 @@ class EventEngineEndpointWrapper {
   void ShutdownUnref() {
     if (shutdown_ref_.fetch_sub(1, std::memory_order_acq_rel) ==
         kShutdownBit + 1) {
-#ifdef GRPC_POSIX_SOCKET_TCP
-      if (fd_ > 0 && on_release_fd_) {
+      if (EventEngineSupportsFd() && fd_ > 0 && on_release_fd_) {
         reinterpret_cast<PosixEndpointWithFdSupport*>(endpoint_.get())
             ->Shutdown(std::move(on_release_fd_));
       }
-#endif  // GRPC_POSIX_SOCKET_TCP
       OnShutdownInternal();
     }
   }
@@ -144,11 +143,9 @@ class EventEngineEndpointWrapper {
   // invocation would simply return.
   void TriggerShutdown(
       absl::AnyInvocable<void(absl::StatusOr<int>)> on_release_fd) {
-#ifdef GRPC_POSIX_SOCKET_TCP
+    if (EventEngineSupportsFd()) {
       on_release_fd_ = std::move(on_release_fd);
-#else
-    (void)on_release_fd;
-#endif  // GRPC_POSIX_SOCKET_TCP
+    }
     int64_t curr = shutdown_ref_.load(std::memory_order_acquire);
     while (true) {
       if (curr & kShutdownBit) {
@@ -160,12 +157,10 @@ class EventEngineEndpointWrapper {
         Ref();
         if (shutdown_ref_.fetch_sub(1, std::memory_order_acq_rel) ==
             kShutdownBit + 1) {
-#ifdef GRPC_POSIX_SOCKET_TCP
-          if (fd_ > 0 && on_release_fd_) {
+          if (EventEngineSupportsFd() && fd_ > 0 && on_release_fd_) {
             reinterpret_cast<PosixEndpointWithFdSupport*>(endpoint_.get())
                 ->Shutdown(std::move(on_release_fd_));
           }
-#endif  // GRPC_POSIX_SOCKET_TCP
           OnShutdownInternal();
         }
         return;
@@ -189,9 +184,7 @@ class EventEngineEndpointWrapper {
   std::unique_ptr<grpc_event_engine_endpoint> eeep_;
   std::atomic<int64_t> refs_{1};
   std::atomic<int64_t> shutdown_ref_{1};
-#ifdef GRPC_POSIX_SOCKET_TCP
   absl::AnyInvocable<void(absl::StatusOr<int>)> on_release_fd_;
-#endif  // GRPC_POSIX_SOCKET_TCP
   grpc_core::Mutex mu_;
   std::string peer_address_;
   std::string local_address_;
@@ -387,12 +380,12 @@ EventEngineEndpointWrapper::EventEngineEndpointWrapper(
   if (peer_addr.ok()) {
     peer_address_ = *peer_addr;
   }
-#ifdef GRPC_POSIX_SOCKET_TCP
+  if (EventEngineSupportsFd()) {
     fd_ = reinterpret_cast<PosixEndpointWithFdSupport*>(endpoint_.get())
               ->GetWrappedFd();
-#else   // GRPC_POSIX_SOCKET_TCP
+  } else {
     fd_ = -1;
-#endif  // GRPC_POSIX_SOCKET_TCP
+  }
   GRPC_EVENT_ENGINE_TRACE("EventEngine::Endpoint %p Create", eeep_->wrapper);
 }
 

src/core/lib/transport/tcp_connect_handshaker.cc

@@ -152,7 +152,6 @@ void TCPConnectHandshaker::DoHandshake(grpc_tcp_server_acceptor* /*acceptor*/,
   // we don't want to pass args->endpoint directly.
   // Instead pass endpoint_ and swap this endpoint to
   // args endpoint on success.
-  // TODO(hork): use EventEngine::Connect if(IsEventEngineClientEnabled())
   grpc_tcp_client_connect(
       &connected_, &endpoint_to_destroy_, interested_parties_,
       grpc_event_engine::experimental::ChannelArgsEndpointConfig(args->args),