Initial checkin of gRPC to third_party/

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

+#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.Utils;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// Manages server side native call lifecycle.
+    /// </summary>
+    internal class AsyncCallServer<TRequest, TResponse> : AsyncCallBase<TResponse, TRequest>
+    {
+        readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
+        readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
+        readonly Server server;
+
+        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment, Server server) : base(serializer, deserializer, environment)
+        {
+            this.server = GrpcPreconditions.CheckNotNull(server);
+        }
+
+        public void Initialize(CallSafeHandle call)
+        {
+            call.Initialize(environment.CompletionRegistry, environment.CompletionQueue);
+
+            server.AddCallReference(this);
+            InitializeInternal(call);
+        }
+
+        /// <summary>
+        /// Starts a server side call.
+        /// </summary>
+        public Task ServerSideCallAsync()
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckNotNull(call);
+
+                started = true;
+
+                call.StartServerSide(HandleFinishedServerside);
+                return finishedServersideTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Sends a streaming response. Only one pending send action is allowed at any given time.
+        /// completionDelegate is called when the operation finishes.
+        /// </summary>
+        public void StartSendMessage(TResponse msg, WriteFlags writeFlags, AsyncCompletionDelegate<object> completionDelegate)
+        {
+            StartSendMessageInternal(msg, writeFlags, completionDelegate);
+        }
+
+        /// <summary>
+        /// Receives a streaming request. Only one pending read action is allowed at any given time.
+        /// completionDelegate is called when the operation finishes.
+        /// </summary>
+        public void StartReadMessage(AsyncCompletionDelegate<TRequest> completionDelegate)
+        {
+            StartReadMessageInternal(completionDelegate);
+        }
+
+        /// <summary>
+        /// Initiates sending a initial metadata. 
+        /// Even though C-core allows sending metadata in parallel to sending messages, we will treat sending metadata as a send message operation
+        /// to make things simpler.
+        /// completionDelegate is invoked upon completion.
+        /// </summary>
+        public void StartSendInitialMetadata(Metadata headers, AsyncCompletionDelegate<object> completionDelegate)
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckNotNull(headers, "metadata");
+                GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
+
+                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();
+
+                GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(headers))
+                {
+                    call.StartSendInitialMetadata(HandleSendFinished, metadataArray);
+                }
+
+                this.initialMetadataSent = true;
+                sendCompletionDelegate = completionDelegate;
+            }
+        }
+
+        /// <summary>
+        /// Sends call result status, also indicating server is done with streaming responses.
+        /// Only one pending send action is allowed at any given time.
+        /// completionDelegate is called when the operation finishes.
+        /// </summary>
+        public void StartSendStatusFromServer(Status status, Metadata trailers, AsyncCompletionDelegate<object> completionDelegate)
+        {
+            lock (myLock)
+            {
+                GrpcPreconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
+                CheckSendingAllowed();
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
+                {
+                    call.StartSendStatusFromServer(HandleHalfclosed, status, metadataArray, !initialMetadataSent);
+                }
+                halfcloseRequested = true;
+                readingDone = true;
+                sendCompletionDelegate = completionDelegate;
+            }
+        }
+
+        /// <summary>
+        /// Gets cancellation token that gets cancelled once close completion
+        /// is received and the cancelled flag is set.
+        /// </summary>
+        public CancellationToken CancellationToken
+        {
+            get
+            {
+                return cancellationTokenSource.Token;
+            }
+        }
+
+        public string Peer
+        {
+            get
+            {
+                return call.GetPeer();
+            }
+        }
+
+        protected override bool IsClient
+        {
+            get { return false; }
+        }
+
+        protected override void CheckReadingAllowed()
+        {
+            base.CheckReadingAllowed();
+            GrpcPreconditions.CheckArgument(!cancelRequested);
+        }
+
+        protected override void OnAfterReleaseResources()
+        {
+            server.RemoveCallReference(this);
+        }
+
+        /// <summary>
+        /// Handles the server side close completion.
+        /// </summary>
+        private void HandleFinishedServerside(bool success, bool cancelled)
+        {
+            lock (myLock)
+            {
+                finished = true;
+                ReleaseResourcesIfPossible();
+            }
+            // TODO(jtattermusch): handle error
+
+            if (cancelled)
+            {
+                cancellationTokenSource.Cancel();
+            }
+
+            finishedServersideTcs.SetResult(null);
+        }
+    }
+}