Initial checkin of gRPC to third_party/

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

+#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.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core.Logging;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// Pool of threads polling on the same completion queue.
+    /// </summary>
+    internal class GrpcThreadPool
+    {
+        static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<GrpcThreadPool>();
+
+        readonly GrpcEnvironment environment;
+        readonly object myLock = new object();
+        readonly List<Thread> threads = new List<Thread>();
+        readonly int poolSize;
+
+        CompletionQueueSafeHandle cq;
+
+        public GrpcThreadPool(GrpcEnvironment environment, int poolSize)
+        {
+            this.environment = environment;
+            this.poolSize = poolSize;
+        }
+
+        public void Start()
+        {
+            lock (myLock)
+            {
+                if (cq != null)
+                {
+                    throw new InvalidOperationException("Already started.");
+                }
+
+                cq = CompletionQueueSafeHandle.Create();
+
+                for (int i = 0; i < poolSize; i++)
+                {
+                    threads.Add(CreateAndStartThread(i));
+                }
+            }
+        }
+
+        public void Stop()
+        {
+            lock (myLock)
+            {
+                cq.Shutdown();
+                foreach (var thread in threads)
+                {
+                    thread.Join();
+                }
+
+                cq.Dispose();
+            }
+        }
+
+        internal CompletionQueueSafeHandle CompletionQueue
+        {
+            get
+            {
+                return cq;
+            }
+        }
+
+        private Thread CreateAndStartThread(int i)
+        {
+            var thread = new Thread(new ThreadStart(RunHandlerLoop));
+            thread.IsBackground = false;
+            thread.Start();
+            thread.Name = "grpc " + i;
+            return thread;
+        }
+
+        /// <summary>
+        /// Body of the polling thread.
+        /// </summary>
+        private void RunHandlerLoop()
+        {
+            CompletionQueueEvent ev;
+            do
+            {
+                ev = cq.Next();
+                if (ev.type == GRPCCompletionType.OpComplete)
+                {
+                    bool success = (ev.success != 0);
+                    IntPtr tag = ev.tag;
+                    try
+                    {
+                        var callback = environment.CompletionRegistry.Extract(tag);
+                        callback(success);
+                    }
+                    catch (Exception e)
+                    {
+                        Logger.Error(e, "Exception occured while invoking completion delegate");
+                    }
+                }
+            }
+            while (ev.type != GRPCCompletionType.Shutdown);
+        }
+    }
+}