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// Copyright 2013 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 "webkit/browser/fileapi/timed_task_helper.h"
#include "base/bind.h"
#include "base/logging.h"
#include "base/sequenced_task_runner.h"
namespace fileapi {
struct TimedTaskHelper::Tracker {
explicit Tracker(TimedTaskHelper* timer) : timer(timer) {}
~Tracker() {
if (timer)
timer->tracker_ = NULL;
}
TimedTaskHelper* timer;
};
TimedTaskHelper::TimedTaskHelper(base::SequencedTaskRunner* task_runner)
: task_runner_(task_runner),
tracker_(NULL) {
}
TimedTaskHelper::~TimedTaskHelper() {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
if (tracker_)
tracker_->timer = NULL;
}
bool TimedTaskHelper::IsRunning() const {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
return tracker_ != NULL;
}
void TimedTaskHelper::Start(
const tracked_objects::Location& posted_from,
base::TimeDelta delay,
const base::Closure& user_task) {
posted_from_ = posted_from;
delay_ = delay;
user_task_ = user_task;
Reset();
}
void TimedTaskHelper::Reset() {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
DCHECK(!user_task_.is_null());
desired_run_time_ = base::TimeTicks::Now() + delay_;
if (tracker_)
return;
// Initialize the tracker for the first time.
tracker_ = new Tracker(this);
PostDelayedTask(make_scoped_ptr(tracker_), delay_);
}
// static
void TimedTaskHelper::Fired(scoped_ptr<Tracker> tracker) {
if (!tracker->timer)
return;
TimedTaskHelper* timer = tracker->timer;
timer->OnFired(tracker.Pass());
}
void TimedTaskHelper::OnFired(scoped_ptr<Tracker> tracker) {
DCHECK(task_runner_->RunsTasksOnCurrentThread());
base::TimeTicks now = base::TimeTicks::Now();
if (desired_run_time_ > now) {
PostDelayedTask(tracker.Pass(), desired_run_time_ - now);
return;
}
tracker.reset();
base::Closure task = user_task_;
user_task_.Reset();
task.Run();
}
void TimedTaskHelper::PostDelayedTask(scoped_ptr<Tracker> tracker,
base::TimeDelta delay) {
task_runner_->PostDelayedTask(
posted_from_,
base::Bind(&TimedTaskHelper::Fired, base::Passed(&tracker)),
delay);
}
} // namespace fileapi
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