Initial checkin of gRPC to third_party/

third_party/grpc/src/cpp/server/dynamic_thread_pool.h

-/* Copyright (c) 2010, Google Inc.
+/*
+ *
+ * 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.
  *
- * ---
- * This file is an internal part spinlock.cc and once.cc
- * It may not be used directly by code outside of //base.
  */
 
-#ifndef BASE_SPINLOCK_INTERNAL_H_
-#define BASE_SPINLOCK_INTERNAL_H_
+#ifndef GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
+#define GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H
 
-#include <config.h>
-#include "base/basictypes.h"
-#include "base/atomicops.h"
+#include <list>
+#include <memory>
+#include <queue>
 
-namespace base {
-namespace internal {
+#include <grpc++/impl/sync.h>
+#include <grpc++/impl/thd.h>
+#include <grpc++/support/config.h>
 
-// SpinLockWait() waits until it can perform one of several transitions from
-// "from" to "to".  It returns when it performs a transition where done==true.
-struct SpinLockWaitTransition {
-  int32 from;
-  int32 to;
-  bool done;
+#include "src/cpp/server/thread_pool_interface.h"
+
+namespace grpc {
+
+class DynamicThreadPool GRPC_FINAL : public ThreadPoolInterface {
+ public:
+  explicit DynamicThreadPool(int reserve_threads);
+  ~DynamicThreadPool();
+
+  void Add(const std::function<void()>& callback) GRPC_OVERRIDE;
+
+ private:
+  class DynamicThread {
+   public:
+    DynamicThread(DynamicThreadPool* pool);
+    ~DynamicThread();
+
+   private:
+    DynamicThreadPool* pool_;
+    std::unique_ptr<grpc::thread> thd_;
+    void ThreadFunc();
+  };
+  grpc::mutex mu_;
+  grpc::condition_variable cv_;
+  grpc::condition_variable shutdown_cv_;
+  bool shutdown_;
+  std::queue<std::function<void()>> callbacks_;
+  int reserve_threads_;
+  int nthreads_;
+  int threads_waiting_;
+  std::list<DynamicThread*> dead_threads_;
+
+  void ThreadFunc();
+  static void ReapThreads(std::list<DynamicThread*>* tlist);
 };
 
-// Wait until *w can transition from trans[i].from to trans[i].to for some i
-// satisfying 0<=i<n && trans[i].done, atomically make the transition,
-// then return the old value of *w.   Make any other atomic tranistions
-// where !trans[i].done, but continue waiting.
-int32 SpinLockWait(volatile Atomic32 *w, int n,
-                   const SpinLockWaitTransition trans[]);
-void SpinLockWake(volatile Atomic32 *w, bool all);
-void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop);
+}  // namespace grpc
 
-} // namespace internal
-} // namespace base
-#endif
+#endif  // GRPC_INTERNAL_CPP_DYNAMIC_THREAD_POOL_H