cc/base/delayed_unique_notifier.cc

   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 #include "cc/base/delayed_unique_notifier.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/location.h"
  10 #include "base/sequenced_task_runner.h"
  11
  12 namespace cc {
  13
  14 DelayedUniqueNotifier::DelayedUniqueNotifier(
  15     base::SequencedTaskRunner* task_runner,
  16     const base::Closure& closure,
  17     const base::TimeDelta& delay)
  18     : task_runner_(task_runner),
  19       closure_(closure),
  20       delay_(delay),
  21       notification_pending_(false),
  22       weak_ptr_factory_(this) {
  23 }
  24
  25 DelayedUniqueNotifier::~DelayedUniqueNotifier() {
  26 }
  27
  28 void DelayedUniqueNotifier::Schedule() {
  29   if (notification_pending_) {
  30     next_notification_time_ = Now() + delay_;
  31     return;
  32   }
  33
  34   next_notification_time_ = Now() + delay_;
  35   task_runner_->PostDelayedTask(FROM_HERE,
  36                                 base::Bind(&DelayedUniqueNotifier::NotifyIfTime,
  37                                            weak_ptr_factory_.GetWeakPtr()),
  38                                 delay_);
  39   notification_pending_ = true;
  40 }
  41
  42 void DelayedUniqueNotifier::Cancel() {
  43   next_notification_time_ = base::TimeTicks();
  44 }
  45
  46 bool DelayedUniqueNotifier::HasPendingNotification() const {
  47   return notification_pending_ && !next_notification_time_.is_null();
  48 }
  49
  50 base::TimeTicks DelayedUniqueNotifier::Now() const {
  51   return base::TimeTicks::Now();
  52 }
  53
  54 void DelayedUniqueNotifier::NotifyIfTime() {
  55   // If next notifiaction time is not valid, then this schedule was canceled.
  56   if (next_notification_time_.is_null()) {
  57     notification_pending_ = false;
  58     return;
  59   }
  60
  61   // If the notification was rescheduled or arrived too early for any other
  62   // reason, then post another task instead of running the callback.
  63   base::TimeTicks now = Now();
  64   if (next_notification_time_ > now) {
  65     task_runner_->PostDelayedTask(
  66         FROM_HERE,
  67         base::Bind(&DelayedUniqueNotifier::NotifyIfTime,
  68                    weak_ptr_factory_.GetWeakPtr()),
  69         next_notification_time_ - now);
  70     return;
  71   }
  72
  73   // Note the order here is important since closure might schedule another run.
  74   notification_pending_ = false;
  75   closure_.Run();
  76 }
  77
  78 }  // namespace cc