Initial checkin of gRPC to third_party/

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

Index: third_party/grpc/src/csharp/Grpc.Core/Internal/AsyncCall.cs
diff --git a/third_party/grpc/src/csharp/Grpc.Core/Internal/AsyncCall.cs b/third_party/grpc/src/csharp/Grpc.Core/Internal/AsyncCall.cs
new file mode 100644
index 0000000000000000000000000000000000000000..2caba260b3a243d43bf9fe72ff627ed5a474acd7
--- /dev/null
+++ b/third_party/grpc/src/csharp/Grpc.Core/Internal/AsyncCall.cs
@@ -0,0 +1,459 @@
+#region Copyright notice and license
+
+// Copyright 2015-2016, 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.Diagnostics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core.Internal;
+using Grpc.Core.Logging;
+using Grpc.Core.Profiling;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// Manages client side native call lifecycle.
+    /// </summary>
+    internal class AsyncCall<TRequest, TResponse> : AsyncCallBase<TRequest, TResponse>
+    {
+        static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<AsyncCall<TRequest, TResponse>>();
+
+        readonly CallInvocationDetails<TRequest, TResponse> details;
+        readonly INativeCall injectedNativeCall;  // for testing
+
+        // Completion of a pending unary response if not null.
+        TaskCompletionSource<TResponse> unaryResponseTcs;
+
+        // Indicates that steaming call has finished.
+        TaskCompletionSource<object> streamingCallFinishedTcs = new TaskCompletionSource<object>();
+
+        // Response headers set here once received.
+        TaskCompletionSource<Metadata> responseHeadersTcs = new TaskCompletionSource<Metadata>();
+
+        // Set after status is received. Used for both unary and streaming response calls.
+        ClientSideStatus? finishedStatus;
+
+        public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails)
+            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer, callDetails.Channel.Environment)
+        {
+            this.details = callDetails.WithOptions(callDetails.Options.Normalize());
+            this.initialMetadataSent = true;  // we always send metadata at the very beginning of the call.
+        }
+
+        /// <summary>
+        /// This constructor should only be used for testing.
+        /// </summary>
+        public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails, INativeCall injectedNativeCall) : this(callDetails)
+        {
+            this.injectedNativeCall = injectedNativeCall;
+        }
+
+        // TODO: this method is not Async, so it shouldn't be in AsyncCall class, but 
+        // it is reusing fair amount of code in this class, so we are leaving it here.
+        /// <summary>
+        /// Blocking unary request - unary response call.
+        /// </summary>
+        public TResponse UnaryCall(TRequest msg)
+        {
+            var profiler = Profilers.ForCurrentThread();
+
+            using (profiler.NewScope("AsyncCall.UnaryCall"))
+            using (CompletionQueueSafeHandle cq = CompletionQueueSafeHandle.Create())
+            {
+                byte[] payload = UnsafeSerialize(msg);
+
+                unaryResponseTcs = new TaskCompletionSource<TResponse>();
+
+                lock (myLock)
+                {
+                    GrpcPreconditions.CheckState(!started);
+                    started = true;
+                    Initialize(cq);
+
+                    halfcloseRequested = true;
+                    readingDone = true;
+                }
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                using (var ctx = BatchContextSafeHandle.Create())
+                {
+                    call.StartUnary(ctx, payload, metadataArray, GetWriteFlagsForCall());
+
+                    var ev = cq.Pluck(ctx.Handle);
+
+                    bool success = (ev.success != 0);
+                    try
+                    {
+                        using (profiler.NewScope("AsyncCall.UnaryCall.HandleBatch"))
+                        {
+                            HandleUnaryResponse(success, ctx.GetReceivedStatusOnClient(), ctx.GetReceivedMessage(), ctx.GetReceivedInitialMetadata());
+                        }
+                    }
+                    catch (Exception e)
+                    {
+                        Logger.Error(e, "Exception occured while invoking completion delegate.");
+                    }
+                }
+                    
+                // Once the blocking call returns, the result should be available synchronously.
+                // Note that GetAwaiter().GetResult() doesn't wrap exceptions in AggregateException.
+                return unaryResponseTcs.Task.GetAwaiter().GetResult();
+            }
+        }
+
+        /// <summary>
+        /// Starts a unary request - unary response call.
+        /// </summary>
+        public Task<TResponse> UnaryCallAsync(TRequest msg)
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckState(!started);
+                started = true;
+
+                Initialize(environment.CompletionQueue);
+
+                halfcloseRequested = true;
+                readingDone = true;
+
+                byte[] payload = UnsafeSerialize(msg);
+
+                unaryResponseTcs = new TaskCompletionSource<TResponse>();
+                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                {
+                    call.StartUnary(HandleUnaryResponse, payload, metadataArray, GetWriteFlagsForCall());
+                }
+                return unaryResponseTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Starts a streamed request - unary response call.
+        /// Use StartSendMessage and StartSendCloseFromClient to stream requests.
+        /// </summary>
+        public Task<TResponse> ClientStreamingCallAsync()
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckState(!started);
+                started = true;
+
+                Initialize(environment.CompletionQueue);
+
+                readingDone = true;
+
+                unaryResponseTcs = new TaskCompletionSource<TResponse>();
+                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                {
+                    call.StartClientStreaming(HandleUnaryResponse, metadataArray);
+                }
+
+                return unaryResponseTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Starts a unary request - streamed response call.
+        /// </summary>
+        public void StartServerStreamingCall(TRequest msg)
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckState(!started);
+                started = true;
+
+                Initialize(environment.CompletionQueue);
+
+                halfcloseRequested = true;
+
+                byte[] payload = UnsafeSerialize(msg);
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                {
+                    call.StartServerStreaming(HandleFinished, payload, metadataArray, GetWriteFlagsForCall());
+                }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
+            }
+        }
+
+        /// <summary>
+        /// Starts a streaming request - streaming response call.
+        /// Use StartSendMessage and StartSendCloseFromClient to stream requests.
+        /// </summary>
+        public void StartDuplexStreamingCall()
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckState(!started);
+                started = true;
+
+                Initialize(environment.CompletionQueue);
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
+                {
+                    call.StartDuplexStreaming(HandleFinished, metadataArray);
+                }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
+            }
+        }
+
+        /// <summary>
+        /// Sends a streaming request. Only one pending send action is allowed at any given time.
+        /// completionDelegate is called when the operation finishes.
+        /// </summary>
+        public void StartSendMessage(TRequest msg, WriteFlags writeFlags, AsyncCompletionDelegate<object> completionDelegate)
+        {
+            StartSendMessageInternal(msg, writeFlags, completionDelegate);
+        }
+
+        /// <summary>
+        /// Receives a streaming response. Only one pending read action is allowed at any given time.
+        /// completionDelegate is called when the operation finishes.
+        /// </summary>
+        public void StartReadMessage(AsyncCompletionDelegate<TResponse> completionDelegate)
+        {
+            StartReadMessageInternal(completionDelegate);
+        }
+
+        /// <summary>
+        /// Sends halfclose, indicating client is done with streaming requests.
+        /// Only one pending send action is allowed at any given time.
+        /// completionDelegate is called when the operation finishes.
+        /// </summary>
+        public void StartSendCloseFromClient(AsyncCompletionDelegate<object> completionDelegate)
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
+                CheckSendingAllowed();
+
+                call.StartSendCloseFromClient(HandleHalfclosed);
+
+                halfcloseRequested = true;
+                sendCompletionDelegate = completionDelegate;
+            }
+        }
+
+        /// <summary>
+        /// Get the task that completes once if streaming call finishes with ok status and throws RpcException with given status otherwise.
+        /// </summary>
+        public Task StreamingCallFinishedTask
+        {
+            get
+            {
+                return streamingCallFinishedTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Get the task that completes once response headers are received.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return responseHeadersTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Gets the resulting status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.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)
+            {
+                GrpcPreconditions.CheckState(finishedStatus.HasValue, "Trailers can only be accessed once the call has finished.");
+                return finishedStatus.Value.Trailers;
+            }
+        }
+
+        public CallInvocationDetails<TRequest, TResponse> Details
+        {
+            get
+            {
+                return this.details;
+            }
+        }
+
+        protected override void OnAfterReleaseResources()
+        {
+            details.Channel.RemoveCallReference(this);
+        }
+
+        protected override bool IsClient
+        {
+            get { return true; }
+        }
+
+        private void Initialize(CompletionQueueSafeHandle cq)
+        {
+            using (Profilers.ForCurrentThread().NewScope("AsyncCall.Initialize"))
+            { 
+                var call = CreateNativeCall(cq);
+
+                details.Channel.AddCallReference(this);
+                InitializeInternal(call);
+                RegisterCancellationCallback();
+            }
+        }
+
+        private INativeCall CreateNativeCall(CompletionQueueSafeHandle cq)
+        {
+            using (Profilers.ForCurrentThread().NewScope("AsyncCall.CreateNativeCall"))
+            { 
+                if (injectedNativeCall != null)
+                {
+                    return injectedNativeCall;  // allows injecting a mock INativeCall in tests.
+                }
+
+                var parentCall = details.Options.PropagationToken != null ? details.Options.PropagationToken.ParentCall : CallSafeHandle.NullInstance;
+
+                var credentials = details.Options.Credentials;
+                using (var nativeCredentials = credentials != null ? credentials.ToNativeCredentials() : null)
+                {
+                    var result = details.Channel.Handle.CreateCall(environment.CompletionRegistry,
+                                 parentCall, ContextPropagationToken.DefaultMask, cq,
+                                 details.Method, details.Host, Timespec.FromDateTime(details.Options.Deadline.Value), nativeCredentials);
+                    return result;
+                }
+            }
+        }
+
+        // Make sure that once cancellationToken for this call is cancelled, Cancel() will be called.
+        private void RegisterCancellationCallback()
+        {
+            var token = details.Options.CancellationToken;
+            if (token.CanBeCanceled)
+            {
+                token.Register(() => this.Cancel());
+            }
+        }
+
+        /// <summary>
+        /// Gets WriteFlags set in callDetails.Options.WriteOptions
+        /// </summary>
+        private WriteFlags GetWriteFlagsForCall()
+        {
+            var writeOptions = details.Options.WriteOptions;
+            return writeOptions != null ? writeOptions.Flags : default(WriteFlags);
+        }
+
+        /// <summary>
+        /// Handles receive status completion for calls with streaming response.
+        /// </summary>
+        private void HandleReceivedResponseHeaders(bool success, Metadata responseHeaders)
+        {
+            responseHeadersTcs.SetResult(responseHeaders);
+        }
+
+        /// <summary>
+        /// Handler for unary response completion.
+        /// </summary>
+        private void HandleUnaryResponse(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders)
+        {
+            using (Profilers.ForCurrentThread().NewScope("AsyncCall.HandleUnaryResponse"))
+            {
+                TResponse msg = default(TResponse);
+                var deserializeException = success ? TryDeserialize(receivedMessage, out msg) : null;
+
+                lock (myLock)
+                {
+                    finished = true;
+
+                    if (deserializeException != null && receivedStatus.Status.StatusCode == StatusCode.OK)
+                    {
+                        receivedStatus = new ClientSideStatus(DeserializeResponseFailureStatus, receivedStatus.Trailers);
+                    }
+                    finishedStatus = receivedStatus;
+
+                    ReleaseResourcesIfPossible();
+
+                }
+
+                responseHeadersTcs.SetResult(responseHeaders);
+
+                var status = receivedStatus.Status;
+
+                if (!success || status.StatusCode != StatusCode.OK)
+                {
+                    unaryResponseTcs.SetException(new RpcException(status));
+                    return;
+                }
+
+                unaryResponseTcs.SetResult(msg);
+            }
+        }
+
+        /// <summary>
+        /// Handles receive status completion for calls with streaming response.
+        /// </summary>
+        private void HandleFinished(bool success, ClientSideStatus receivedStatus)
+        {
+            lock (myLock)
+            {
+                finished = true;
+                finishedStatus = receivedStatus;
+
+                ReleaseResourcesIfPossible();
+            }
+
+            var status = receivedStatus.Status;
+
+            if (!success || status.StatusCode != StatusCode.OK)
+            {
+                streamingCallFinishedTcs.SetException(new RpcException(status));
+                return;
+            }
+
+            streamingCallFinishedTcs.SetResult(null);
+        }
+    }
+}