// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/base/unique_notifier.h"

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/location.h"
#include "base/sequenced_task_runner.h"

namespace cc {

UniqueNotifier::UniqueNotifier(base::SequencedTaskRunner* task_runner,
                               const base::Closure& closure)
    : task_runner_(task_runner),
      closure_(closure),
      notification_pending_(false),
      weak_ptr_factory_(this) {
}

UniqueNotifier::~UniqueNotifier() {
}

void UniqueNotifier::Cancel() {
  notification_pending_ = false;
}

void UniqueNotifier::Schedule() {
  if (notification_pending_)
    return;

  task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&UniqueNotifier::Notify, weak_ptr_factory_.GetWeakPtr()));
  notification_pending_ = true;
}

void UniqueNotifier::Notify() {
  if (!notification_pending_)
    return;

  // Note that the order here is important in case closure schedules another
  // run.
  notification_pending_ = false;
  closure_.Run();
}

}  // namespace cc