modify client call interface to allow reading status and trailers

src/csharp/Grpc.Core/AsyncClientStreamingCall.cs

@@ -44,12 +44,16 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly Task<TResponse> result;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> result, Action disposeAction)
+        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> result, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.result = result;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
         }
 
@@ -85,7 +89,7 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Provides means to provide after the call.
+        /// Provides means to cleanup after the call.
         /// If the call has already finished normally (request stream has been completed and call result has been received), doesn't do anything.
         /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
         /// As a result, all resources being used by the call should be released eventually.

src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs

@@ -44,15 +44,20 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Action disposeAction)
+        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseStream = responseStream;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
         }
         
+
         /// <summary>
         /// Async stream to read streaming responses.
         /// </summary>
@@ -75,6 +80,24 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
         /// <summary>
         /// Provides means to cleanup after the call.
         /// If the call has already finished normally (request stream has been completed and response stream has been fully read), doesn't do anything.

src/csharp/Grpc.Core/AsyncServerStreamingCall.cs

@@ -43,11 +43,15 @@ namespace Grpc.Core
     public sealed class AsyncServerStreamingCall<TResponse> : IDisposable
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Action disposeAction)
+        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseStream = responseStream;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
         }
 
@@ -62,6 +66,24 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
         /// <summary>
         /// Provides means to cleanup after the call.
         /// If the call has already finished normally (response stream has been fully read), doesn't do anything.

src/csharp/Grpc.Core/AsyncUnaryCall.cs

@@ -0,0 +1,106 @@
+#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.CompilerServices;
+using System.Threading.Tasks;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Return type for single request - single response call.
+    /// </summary>
+    public sealed class AsyncUnaryCall<TResponse> : IDisposable
+    {
+        readonly Task<TResponse> result;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
+        readonly Action disposeAction;
+
+        public AsyncUnaryCall(Task<TResponse> result, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        {
+            this.result = result;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
+            this.disposeAction = disposeAction;
+        }
+
+        /// <summary>
+        /// Asynchronous call result.
+        /// </summary>
+        public Task<TResponse> Result
+        {
+            get
+            {
+                return this.result;
+            }
+        }
+
+        /// <summary>
+        /// Allows awaiting this object directly.
+        /// </summary>
+        public TaskAwaiter<TResponse> GetAwaiter()
+        {
+            return result.GetAwaiter();
+        }
+
+        /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
+        /// <summary>
+        /// Provides means to cleanup after the call.
+        /// If the call has already finished normally (request stream has been completed and call result has been received), doesn't do anything.
+        /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
+        /// As a result, all resources being used by the call should be released eventually.
+        /// </summary>
+        public void Dispose()
+        {
+            disposeAction.Invoke();
+        }
+    }
+}

src/csharp/Grpc.Core/Calls.cs

@@ -73,7 +73,7 @@ namespace Grpc.Core
             asyncCall.StartServerStreamingCall(req, call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.Cancel);
+            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         public static AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, CancellationToken token)
@@ -85,7 +85,7 @@ namespace Grpc.Core
             var resultTask = asyncCall.ClientStreamingCallAsync(call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
-            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.Cancel);
+            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         public static AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, CancellationToken token)
@@ -98,7 +98,7 @@ namespace Grpc.Core
             RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.Cancel);
+            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         private static void RegisterCancellationCallback<TRequest, TResponse>(AsyncCall<TRequest, TResponse> asyncCall, CancellationToken token)

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

@@ -33,13 +33,12 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
-    <Reference Include="System.Collections.Immutable, Version=1.1.36.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\packages\System.Collections.Immutable.1.1.36\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
-    </Reference>
     <Reference Include="System.Interactive.Async">
       <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
     </Reference>
+    <Reference Include="System.Collections.Immutable">
+      <HintPath>..\packages\System.Collections.Immutable.1.1.36\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="AsyncDuplexStreamingCall.cs" />
@@ -102,6 +101,7 @@
     <Compile Include="Internal\CompletionRegistry.cs" />
     <Compile Include="Internal\BatchContextSafeHandle.cs" />
     <Compile Include="ChannelOptions.cs" />
+    <Compile Include="AsyncUnaryCall.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Grpc.Core.nuspec" />

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

@@ -52,8 +52,8 @@ namespace Grpc.Core.Internal
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
-        // Set after status is received. Only used for streaming response calls.
-        Status? finishedStatus;
+        // Set after status is received. Used for both unary and streaming response calls.
+        ClientSideStatus? finishedStatus;
 
         bool readObserverCompleted;  // True if readObserver has already been completed.
 
@@ -248,6 +248,32 @@ namespace Grpc.Core.Internal
             }
         }
 
+        /// <summary>
+        /// Gets the resulting status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            lock (myLock)
+            {
+                Preconditions.CheckState(finishedStatus.HasValue, "Status can only be accessed once the call has finished.");
+                return finishedStatus.Value.Status;
+            }
+        }
+
+        /// <summary>
+        /// Gets the trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            lock (myLock)
+            {
+                Preconditions.CheckState(finishedStatus.HasValue, "Trailers can only be accessed once the call has finished.");
+                return finishedStatus.Value.Trailers;
+            }
+        }
+
         /// <summary>
         /// On client-side, we only fire readCompletionDelegate once all messages have been read 
         /// and status has been received.
@@ -265,7 +291,7 @@ namespace Grpc.Core.Internal
 
                 if (shouldComplete)
                 {
-                    var status = finishedStatus.Value;
+                    var status = finishedStatus.Value.Status;
                     if (status.StatusCode != StatusCode.OK)
                     {
                         FireCompletion(completionDelegate, default(TResponse), new RpcException(status));
@@ -288,9 +314,13 @@ namespace Grpc.Core.Internal
         /// </summary>
         private void HandleUnaryResponse(bool success, BatchContextSafeHandle ctx)
         {
+            var fullStatus = ctx.GetReceivedStatusOnClient();
+
             lock (myLock)
             {
                 finished = true;
+                finishedStatus = fullStatus;
+
                 halfclosed = true;
 
                 ReleaseResourcesIfPossible();
@@ -302,7 +332,6 @@ namespace Grpc.Core.Internal
                 return;
             }
 
-            var fullStatus = ctx.GetReceivedStatusOnClient();
             var status = fullStatus.Status;
 
             if (status.StatusCode != StatusCode.OK)
@@ -324,13 +353,12 @@ namespace Grpc.Core.Internal
         private void HandleFinished(bool success, BatchContextSafeHandle ctx)
         {
             var fullStatus = ctx.GetReceivedStatusOnClient();
-            var status = fullStatus.Status;
 
             AsyncCompletionDelegate<TResponse> origReadCompletionDelegate = null;
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = status;
+                finishedStatus = fullStatus;
 
                 origReadCompletionDelegate = readCompletionDelegate;