allow halfclose after close on clients

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

@@ -93,6 +93,7 @@
     <Compile Include="MetadataTest.cs" />
     <Compile Include="PerformanceTest.cs" />
     <Compile Include="SanityTest.cs" />
+    <Compile Include="HalfcloseTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>

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

@@ -0,0 +1,98 @@
+#region Copyright notice and license
+
+// Copyright 2016, 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.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
+{
+    public class HalfcloseTest
+    {
+        MockServiceHelper helper;
+        Server server;
+        Channel channel;
+
+        [SetUp]
+        public void Init()
+        {
+            helper = new MockServiceHelper();
+
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+        }
+
+        [TearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+
+        /// <summary>
+        /// For client streaming and duplex streaming calls, if server does a full close
+        /// before we halfclose the request stream, an attempt to halfclose
+        /// (complete the request stream) shouldn't be treated as an error.
+        /// </summary>
+        /// <returns>The after fullclose client streaming call.</returns>
+        [Test]
+        public async Task HalfcloseAfterFullclose_ClientStreamingCall()
+        {
+            helper.ClientStreamingHandler = new ClientStreamingServerMethod<string, string>(async (requestStream, context) =>
+            {
+                return "PASS";
+            });
+
+            var call = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall());
+            // make sure server has fullclosed on us
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+
+            // sending close from client should be still fine because server can finish
+            // the call anytime and we cannot do anything about it on the client side.
+            await call.RequestStream.CompleteAsync();
+
+            // Second attempt to close from client is not allowed.
+            Assert.Throws(typeof(InvalidOperationException), async () => await call.RequestStream.CompleteAsync());
+        }
+    }
+}

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

@@ -258,9 +258,19 @@ namespace Grpc.Core.Internal
             lock (myLock)
             {
                 GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
-                CheckSendingAllowed();
+                CheckSendingAllowed(allowFinished: true);
 
-                call.StartSendCloseFromClient(HandleHalfclosed);
+                if (!disposed && !finished)
+                {
+                    call.StartSendCloseFromClient(HandleSendCloseFromClientFinished);
+                }
+                else
+                {
+                    // In case the call has already been finished by the serverside,
+                    // the halfclose has already been done implicitly, so we only
+                    // emit the notification for the completion delegate.
+                    Task.Run(() => HandleSendCloseFromClientFinished(true));
+                }
 
                 halfcloseRequested = true;
                 sendCompletionDelegate = completionDelegate;

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

@@ -136,7 +136,7 @@ namespace Grpc.Core.Internal
             lock (myLock)
             {
                 GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
-                CheckSendingAllowed();
+                CheckSendingAllowed(allowFinished: false);
 
                 call.StartSendMessage(HandleSendFinished, payload, writeFlags, !initialMetadataSent);
 
@@ -202,14 +202,14 @@ namespace Grpc.Core.Internal
         {
         }
 
-        protected void CheckSendingAllowed()
+        protected void CheckSendingAllowed(bool allowFinished)
         {
             GrpcPreconditions.CheckState(started);
             CheckNotCancelled();
-            GrpcPreconditions.CheckState(!disposed);
+            GrpcPreconditions.CheckState(!disposed || allowFinished);
 
             GrpcPreconditions.CheckState(!halfcloseRequested, "Already halfclosed.");
-            GrpcPreconditions.CheckState(!finished, "Already finished.");
+            GrpcPreconditions.CheckState(!finished || allowFinished, "Already finished.");
             GrpcPreconditions.CheckState(sendCompletionDelegate == null, "Only one write can be pending at a time");
         }
 
@@ -294,9 +294,33 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
-        /// Handles halfclose completion.
+        /// Handles halfclose (send close from client) completion.
+        /// </summary>
+        protected void HandleSendCloseFromClientFinished(bool success)
+        {
+            AsyncCompletionDelegate<object> origCompletionDelegate = null;
+            lock (myLock)
+            {
+                origCompletionDelegate = sendCompletionDelegate;
+                sendCompletionDelegate = null;
+
+                ReleaseResourcesIfPossible();
+            }
+
+            if (!success)
+            {
+                FireCompletion(origCompletionDelegate, null, new InvalidOperationException("Sending close from client has failed."));
+            }
+            else
+            {
+                FireCompletion(origCompletionDelegate, null, null);
+            }
+        }
+
+        /// <summary>
+        /// Handles send status from server completion.
         /// </summary>
-        protected void HandleHalfclosed(bool success)
+        protected void HandleSendStatusFromServerFinished(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
@@ -309,7 +333,7 @@ namespace Grpc.Core.Internal
 
             if (!success)
             {
-                FireCompletion(origCompletionDelegate, null, new InvalidOperationException("Halfclose failed"));
+                FireCompletion(origCompletionDelegate, null, new InvalidOperationException("Error sending status from server."));
             }
             else
             {

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

@@ -113,7 +113,7 @@ namespace Grpc.Core.Internal
 
                 GrpcPreconditions.CheckState(!initialMetadataSent, "Response headers can only be sent once per call.");
                 GrpcPreconditions.CheckState(streamingWritesCounter == 0, "Response headers can only be sent before the first write starts.");
-                CheckSendingAllowed();
+                CheckSendingAllowed(allowFinished: false);
 
                 GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
 
@@ -137,11 +137,11 @@ namespace Grpc.Core.Internal
             lock (myLock)
             {
                 GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
-                CheckSendingAllowed();
+                CheckSendingAllowed(allowFinished: false);
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
                 {
-                    call.StartSendStatusFromServer(HandleHalfclosed, status, metadataArray, !initialMetadataSent);
+                    call.StartSendStatusFromServer(HandleSendStatusFromServerFinished, status, metadataArray, !initialMetadataSent);
                 }
                 halfcloseRequested = true;
                 readingDone = true;

src/csharp/tests.json

@@ -21,6 +21,7 @@
     "Grpc.Core.Tests.CompressionTest",
     "Grpc.Core.Tests.ContextPropagationTest",
     "Grpc.Core.Tests.GrpcEnvironmentTest",
+    "Grpc.Core.Tests.HalfcloseTest",
     "Grpc.Core.Tests.MarshallingErrorsTest",
     "Grpc.Core.Tests.MetadataTest",
     "Grpc.Core.Tests.NUnitVersionTest",