cc/base/unique_notifier.h

   1 // Copyright 2014 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 CC_BASE_UNIQUE_NOTIFIER_H_
   6 #define CC_BASE_UNIQUE_NOTIFIER_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "cc/base/cc_export.h"
  11
  12 namespace base {
  13 class SequencedTaskRunner;
  14 }  // namespace base
  15
  16 namespace cc {
  17
  18 class CC_EXPORT UniqueNotifier {
  19  public:
  20   // Configure this notifier to issue the |closure| notification when scheduled.
  21   UniqueNotifier(base::SequencedTaskRunner* task_runner,
  22                  const base::Closure& closure);
  23
  24   // Destroying the notifier will ensure that no further notifications will
  25   // happen from this class.
  26   ~UniqueNotifier();
  27
  28   // Schedule a notification to be run. If another notification is already
  29   // pending, then only one notification will take place.
  30   void Schedule();
  31
  32   // Cancel a pending notification, if one was scheduled.
  33   void Cancel();
  34
  35  private:
  36   void Notify();
  37
  38   // TODO(dcheng): How come this doesn't need to hold a ref to the task runner?
  39   base::SequencedTaskRunner* task_runner_;
  40   base::Closure closure_;
  41   bool notification_pending_;
  42
  43   base::WeakPtrFactory<UniqueNotifier> weak_ptr_factory_;
  44
  45   DISALLOW_COPY_AND_ASSIGN(UniqueNotifier);
  46 };
  47
  48 }  // namespace cc
  49
  50 #endif  // CC_BASE_UNIQUE_NOTIFIER_H_