base/message_loop/message_loop_task_runner.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_MESSAGE_LOOP_MESSAGE_LOOP_TASK_RUNNER_H_
   6 #define BASE_MESSAGE_LOOP_MESSAGE_LOOP_TASK_RUNNER_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/pending_task.h"
  11 #include "base/single_thread_task_runner.h"
  12 #include "base/synchronization/lock.h"
  13 #include "base/threading/platform_thread.h"
  14
  15 namespace base {
  16 namespace internal {
  17
  18 class IncomingTaskQueue;
  19
  20 // A stock implementation of SingleThreadTaskRunner that is created and managed
  21 // by a MessageLoop. For now a MessageLoopTaskRunner can only be created as
  22 // part of a MessageLoop.
  23 class BASE_EXPORT MessageLoopTaskRunner : public SingleThreadTaskRunner {
  24  public:
  25   explicit MessageLoopTaskRunner(
  26       scoped_refptr<IncomingTaskQueue> incoming_queue);
  27
  28   // Initialize this message loop task runner on the current thread.
  29   void BindToCurrentThread();
  30
  31   // SingleThreadTaskRunner implementation
  32   bool PostDelayedTask(const tracked_objects::Location& from_here,
  33                        const base::Closure& task,
  34                        base::TimeDelta delay) override;
  35   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
  36                                   const base::Closure& task,
  37                                   base::TimeDelta delay) override;
  38   bool RunsTasksOnCurrentThread() const override;
  39
  40  private:
  41   friend class RefCountedThreadSafe<MessageLoopTaskRunner>;
  42   ~MessageLoopTaskRunner() override;
  43
  44   // The incoming queue receiving all posted tasks.
  45   scoped_refptr<IncomingTaskQueue> incoming_queue_;
  46
  47   // ID of the thread |this| was created on.  Could be accessed on multiple
  48   // threads, protected by |valid_thread_id_lock_|.
  49   PlatformThreadId valid_thread_id_;
  50   mutable Lock valid_thread_id_lock_;
  51
  52   DISALLOW_COPY_AND_ASSIGN(MessageLoopTaskRunner);
  53 };
  54
  55 }  // namespace internal
  56 }  // namespace base
  57
  58 #endif  // BASE_MESSAGE_LOOP_MESSAGE_LOOP_TASK_RUNNER_H_