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/macros.h"
10 #include "base/memory/ref_counted.h"
11 #include "base/pending_task.h"
12 #include "base/single_thread_task_runner.h"
13 #include "base/synchronization/lock.h"
14 #include "base/threading/platform_thread.h"
15 
16 namespace base {
17 namespace internal {
18 
19 class IncomingTaskQueue;
20 
21 // A stock implementation of SingleThreadTaskRunner that is created and managed
22 // by a MessageLoop. For now a MessageLoopTaskRunner can only be created as
23 // part of a MessageLoop.
24 class BASE_EXPORT MessageLoopTaskRunner : public SingleThreadTaskRunner {
25  public:
26   explicit MessageLoopTaskRunner(
27       scoped_refptr<IncomingTaskQueue> incoming_queue);
28 
29   // Initialize this message loop task runner on the current thread.
30   void BindToCurrentThread();
31 
32   // SingleThreadTaskRunner implementation
33   bool PostDelayedTask(const tracked_objects::Location& from_here,
34                        const base::Closure& task,
35                        base::TimeDelta delay) override;
36   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
37                                   const base::Closure& task,
38                                   base::TimeDelta delay) override;
39   bool RunsTasksOnCurrentThread() const override;
40 
41  private:
42   friend class RefCountedThreadSafe<MessageLoopTaskRunner>;
43   ~MessageLoopTaskRunner() override;
44 
45   // The incoming queue receiving all posted tasks.
46   scoped_refptr<IncomingTaskQueue> incoming_queue_;
47 
48   // ID of the thread |this| was created on.  Could be accessed on multiple
49   // threads, protected by |valid_thread_id_lock_|.
50   PlatformThreadId valid_thread_id_;
51   mutable Lock valid_thread_id_lock_;
52 
53   DISALLOW_COPY_AND_ASSIGN(MessageLoopTaskRunner);
54 };
55 
56 }  // namespace internal
57 }  // namespace base
58 
59 #endif  // BASE_MESSAGE_LOOP_MESSAGE_LOOP_TASK_RUNNER_H_
60