Allow external TaskQueue implementations on Linux

webrtc/rtc_base/task_queue.h

 /*
  *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_RTC_BASE_TASK_QUEUE_H_
 #define WEBRTC_RTC_BASE_TASK_QUEUE_H_
 
 #include <list>
 #include <memory>
 #include <queue>
 
-#if defined(WEBRTC_MAC) && !defined(WEBRTC_BUILD_LIBEVENT)
+#if defined(WEBRTC_MAC)
 #include <dispatch/dispatch.h>
 #endif
 
 #include "webrtc/rtc_base/constructormagic.h"
 #include "webrtc/rtc_base/criticalsection.h"
+#include "webrtc/rtc_base/scoped_ref_ptr.h"
 
-#if defined(WEBRTC_WIN) || defined(WEBRTC_BUILD_LIBEVENT)
+#if defined(WEBRTC_WIN)
 #include "webrtc/rtc_base/platform_thread.h"
 #endif
 
-#if defined(WEBRTC_BUILD_LIBEVENT)
-#include "webrtc/rtc_base/refcountedobject.h"
-#include "webrtc/rtc_base/scoped_ref_ptr.h"
-
-struct event_base;
-struct event;
-#endif
-
 namespace rtc {
 
 // Base interface for asynchronously executed tasks.
 // The interface basically consists of a single function, Run(), that executes
 // on the target queue.  For more details see the Run() method and TaskQueue.
 class QueuedTask {
  public:
   QueuedTask() {}
   virtual ~QueuedTask() {}
 
@@ skipping 188 matching lines @@
   }
 
   template <class Closure1, class Closure2>
   void PostTaskAndReply(const Closure1& task, const Closure2& reply) {
     PostTaskAndReply(
         std::unique_ptr<QueuedTask>(new ClosureTask<Closure1>(task)),
         std::unique_ptr<QueuedTask>(new ClosureTask<Closure2>(reply)));
   }
 
  private:
-#if defined(WEBRTC_BUILD_LIBEVENT)
-  static void ThreadMain(void* context);
-  static void OnWakeup(int socket, short flags, void* context);  // NOLINT
-  static void RunTask(int fd, short flags, void* context);       // NOLINT
-  static void RunTimer(int fd, short flags, void* context);      // NOLINT
-
-  class ReplyTaskOwner;
-  class PostAndReplyTask;
-  class SetTimerTask;
-
-  typedef RefCountedObject<ReplyTaskOwner> ReplyTaskOwnerRef;
-
-  void PrepareReplyTask(scoped_refptr<ReplyTaskOwnerRef> reply_task);
-
-  struct QueueContext;
-
-  int wakeup_pipe_in_ = -1;
-  int wakeup_pipe_out_ = -1;
-  event_base* event_base_;
-  std::unique_ptr<event> wakeup_event_;
-  PlatformThread thread_;
-  rtc::CriticalSection pending_lock_;
-  std::list<std::unique_ptr<QueuedTask>> pending_ GUARDED_BY(pending_lock_);
-  std::list<scoped_refptr<ReplyTaskOwnerRef>> pending_replies_
-      GUARDED_BY(pending_lock_);
-#elif defined(WEBRTC_MAC)
+#if defined(WEBRTC_MAC)
   struct QueueContext;
   struct TaskContext;
   struct PostTaskAndReplyContext;
   dispatch_queue_t queue_;
   QueueContext* const context_;
 #elif defined(WEBRTC_WIN)
   class ThreadState;
   void RunPendingTasks();
   static void ThreadMain(void* context);
 
   class WorkerThread : public PlatformThread {
    public:
     WorkerThread(ThreadRunFunction func,
                  void* obj,
                  const char* thread_name,
                  ThreadPriority priority)
         : PlatformThread(func, obj, thread_name, priority) {}
 
     bool QueueAPC(PAPCFUNC apc_function, ULONG_PTR data) {
       return PlatformThread::QueueAPC(apc_function, data);
     }
   };
   WorkerThread thread_;
   rtc::CriticalSection pending_lock_;
   std::queue<std::unique_ptr<QueuedTask>> pending_ GUARDED_BY(pending_lock_);
   HANDLE in_queue_;
 #else
-#error not supported.
+  class Impl;
+  const scoped_refptr<Impl> impl_;
 #endif
 
   RTC_DISALLOW_COPY_AND_ASSIGN(TaskQueue);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_RTC_BASE_TASK_QUEUE_H_