Do not issue more message when the call is canceled

1 files changed, 45 insertions, 16 deletions

diff --git a/src/objective-c/GRPCClient/GRPCCall.m b/src/objective-c/GRPCClient/GRPCCall.m
index 7e0640e8ae..23c8d0f2d7 100644
--- a/src/objective-c/GRPCClient/GRPCCall.m
+++ b/src/objective-c/GRPCClient/GRPCCall.m
@@ -104,6 +104,11 @@ const char *kCFStreamVarName = "grpc_cfstream";
   dispatch_queue_t _dispatchQueue;
   /** Flags whether call has started. */
   BOOL _started;
+  /**
+   * Flags that the call has been canceled. When this is true, pending initial metadata and message
+   * should not be issued to \a _handler. This ivar must be accessed with lock to self.
+   */
+  BOOL _canceled;
 }
 
 - (instancetype)initWithRequestOptions:(GRPCRequestOptions *)requestOptions
@@ -135,6 +140,7 @@ const char *kCFStreamVarName = "grpc_cfstream";
     }
     dispatch_set_target_queue(responseHandler.dispatchQueue, _dispatchQueue);
     _started = NO;
+    _canceled = NO;
   }
 
   return self;
@@ -217,6 +223,9 @@ const char *kCFStreamVarName = "grpc_cfstream";
       self->_pipe = nil;
     }
     if (self->_handler) {
+      @synchronized(self) {
+        self->_canceled = YES;
+      }
       id<GRPCResponseHandler> handler = self->_handler;
       dispatch_async(handler.dispatchQueue, ^{
         if ([handler respondsToSelector:@selector(closedWithTrailingMetadata:error:)]) {
@@ -252,30 +261,50 @@ const char *kCFStreamVarName = "grpc_cfstream";
 }
 
 - (void)issueInitialMetadata:(NSDictionary *)initialMetadata {
-  id<GRPCResponseHandler> handler = _handler;
-  if ([handler respondsToSelector:@selector(receivedInitialMetadata:)]) {
-    dispatch_async(handler.dispatchQueue, ^{
-      [handler receivedInitialMetadata:initialMetadata];
-    });
+  if (_handler != nil && initialMetadata != nil) {
+    id<GRPCResponseHandler> handler = _handler;
+    if ([handler respondsToSelector:@selector(receivedInitialMetadata:)]) {
+      dispatch_async(handler.dispatchQueue, ^{
+        // Do not issue initial metadata if the call is already canceled.
+        __block BOOL canceled = NO;
+        @synchronized(self) {
+          canceled = self->_canceled;
+        }
+        if (!canceled) {
+          [handler receivedInitialMetadata:initialMetadata];
+        }
+      });
+    }
   }
 }
 
 - (void)issueMessage:(id)message {
-  id<GRPCResponseHandler> handler = _handler;
-  if ([handler respondsToSelector:@selector(receivedRawMessage:)]) {
-    dispatch_async(handler.dispatchQueue, ^{
-      [handler receivedRawMessage:message];
-    });
+  if (_handler != nil && message != nil) {
+    id<GRPCResponseHandler> handler = _handler;
+    if ([handler respondsToSelector:@selector(receivedRawMessage:)]) {
+      dispatch_async(handler.dispatchQueue, ^{
+        // Do not issue message if the call is already canceled.
+        __block BOOL canceled = NO;
+        @synchronized(self) {
+          canceled = self->_canceled;
+        }
+        if (!canceled) {
+          [handler receivedRawMessage:message];
+        }
+      });
+    }
   }
 }
 
 - (void)issueClosedWithTrailingMetadata:(NSDictionary *)trailingMetadata error:(NSError *)error {
-  id<GRPCResponseHandler> handler = _handler;
-  NSDictionary *trailers = _call.responseTrailers;
-  if ([handler respondsToSelector:@selector(closedWithTrailingMetadata:error:)]) {
-    dispatch_async(handler.dispatchQueue, ^{
-      [handler closedWithTrailingMetadata:trailers error:error];
-    });
+  if (_handler != nil) {
+    id<GRPCResponseHandler> handler = _handler;
+    NSDictionary *trailers = _call.responseTrailers;
+    if ([handler respondsToSelector:@selector(closedWithTrailingMetadata:error:)]) {
+      dispatch_async(handler.dispatchQueue, ^{
+        [handler closedWithTrailingMetadata:trailers error:error];
+      });
+    }
   }
 }