Initial checkin of gRPC to third_party/

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

-#region Copyright notice and license
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
+#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.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
 
-namespace Google.Protobuf
+namespace Grpc.Core.Internal
 {
-    /// <summary>
-    /// Provides a utility routine to copy small arrays much more quickly than Buffer.BlockCopy
-    /// </summary>
-    internal static class ByteArray
+    internal class ClientResponseStream<TRequest, TResponse> : IAsyncStreamReader<TResponse>
+        where TRequest : class
+        where TResponse : class
     {
-        /// <summary>
-        /// The threshold above which you should use Buffer.BlockCopy rather than ByteArray.Copy
-        /// </summary>
-        private const int CopyThreshold = 12;
+        readonly AsyncCall<TRequest, TResponse> call;
+        TResponse current;
 
-        /// <summary>
-        /// Determines which copy routine to use based on the number of bytes to be copied.
-        /// </summary>
-        internal static void Copy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)
+        public ClientResponseStream(AsyncCall<TRequest, TResponse> call)
         {
-            if (count > CopyThreshold)
+            this.call = call;
+        }
+
+        public TResponse Current
+        {
+            get
             {
-                Buffer.BlockCopy(src, srcOffset, dst, dstOffset, count);
-            }
-            else
-            {
-                int stop = srcOffset + count;
-                for (int i = srcOffset; i < stop; i++)
+                if (current == null)
                 {
-                    dst[dstOffset++] = src[i];
+                    throw new InvalidOperationException("No current element is available.");
                 }
+                return current;
             }
         }
 
-        /// <summary>
-        /// Reverses the order of bytes in the array
-        /// </summary>
-        internal static void Reverse(byte[] bytes)
+        public async Task<bool> MoveNext(CancellationToken token)
         {
-            for (int first = 0, last = bytes.Length - 1; first < last; first++, last--)
+            if (token != CancellationToken.None)
             {
-                byte temp = bytes[first];
-                bytes[first] = bytes[last];
-                bytes[last] = temp;
+                throw new InvalidOperationException("Cancellation of individual reads is not supported.");
             }
+            var taskSource = new AsyncCompletionTaskSource<TResponse>();
+            call.StartReadMessage(taskSource.CompletionDelegate);
+            var result = await taskSource.Task.ConfigureAwait(false);
+            this.current = result;
+
+            if (result == null)
+            {
+                await call.StreamingCallFinishedTask.ConfigureAwait(false);
+                return false;
+            }
+            return true;
+        }
+
+        public void Dispose()
+        {
+            // TODO(jtattermusch): implement the semantics of stream disposal.
         }
     }
-}
+}