base/message_loop_proxy_impl.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_PROXY_IMPL_H_
   6 #define BASE_MESSAGE_LOOP_PROXY_IMPL_H_
   7
   8 #include "base/base_export.h"
   9 #include "base/message_loop.h"
  10 #include "base/message_loop_proxy.h"
  11 #include "base/synchronization/lock.h"
  12
  13 namespace base {
  14
  15 // A stock implementation of MessageLoopProxy that is created and managed by a
  16 // MessageLoop. For now a MessageLoopProxyImpl can only be created as part of a
  17 // MessageLoop.
  18 class BASE_EXPORT MessageLoopProxyImpl : public MessageLoopProxy {
  19  public:
  20   // MessageLoopProxy implementation
  21   virtual bool PostDelayedTask(const tracked_objects::Location& from_here,
  22                                const base::Closure& task,
  23                                base::TimeDelta delay) OVERRIDE;
  24   virtual bool PostNonNestableDelayedTask(
  25       const tracked_objects::Location& from_here,
  26       const base::Closure& task,
  27       base::TimeDelta delay) OVERRIDE;
  28   virtual bool RunsTasksOnCurrentThread() const OVERRIDE;
  29
  30  protected:
  31   virtual ~MessageLoopProxyImpl();
  32
  33   // Override OnDestruct so that we can delete the object on the target message
  34   // loop if it still exists.
  35   virtual void OnDestruct() const OVERRIDE;
  36
  37  private:
  38   // Allow the MessageLoop to create a MessageLoopProxyImpl.
  39   friend class ::MessageLoop;
  40   friend class DeleteHelper<MessageLoopProxyImpl>;
  41
  42   MessageLoopProxyImpl();
  43
  44   // Called directly by MessageLoop::~MessageLoop.
  45   virtual void WillDestroyCurrentMessageLoop();
  46
  47
  48   bool PostTaskHelper(const tracked_objects::Location& from_here,
  49                       const base::Closure& task,
  50                       base::TimeDelta delay,
  51                       bool nestable);
  52
  53   // The lock that protects access to target_message_loop_.
  54   mutable base::Lock message_loop_lock_;
  55   MessageLoop* target_message_loop_;
  56
  57   DISALLOW_COPY_AND_ASSIGN(MessageLoopProxyImpl);
  58 };
  59
  60 }  // namespace base
  61
  62 #endif  // BASE_MESSAGE_LOOP_PROXY_IMPL_H_