1 // Copyright 2013 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 "webkit/browser/fileapi/timed_task_helper.h"
6
7 #include "base/bind.h"
8 #include "base/logging.h"
9 #include "base/sequenced_task_runner.h"
10
11 namespace fileapi {
12
13 struct TimedTaskHelper::Tracker {
Trackerfileapi::TimedTaskHelper::Tracker14 explicit Tracker(TimedTaskHelper* timer) : timer(timer) {}
15
~Trackerfileapi::TimedTaskHelper::Tracker16 ~Tracker() {
17 if (timer)
18 timer->tracker_ = NULL;
19 }
20
21 TimedTaskHelper* timer;
22 };
23
TimedTaskHelper(base::SequencedTaskRunner * task_runner)24 TimedTaskHelper::TimedTaskHelper(base::SequencedTaskRunner* task_runner)
25 : task_runner_(task_runner),
26 tracker_(NULL) {
27 }
28
~TimedTaskHelper()29 TimedTaskHelper::~TimedTaskHelper() {
30 DCHECK(task_runner_->RunsTasksOnCurrentThread());
31 if (tracker_)
32 tracker_->timer = NULL;
33 }
34
IsRunning() const35 bool TimedTaskHelper::IsRunning() const {
36 DCHECK(task_runner_->RunsTasksOnCurrentThread());
37 return tracker_ != NULL;
38 }
39
Start(const tracked_objects::Location & posted_from,base::TimeDelta delay,const base::Closure & user_task)40 void TimedTaskHelper::Start(
41 const tracked_objects::Location& posted_from,
42 base::TimeDelta delay,
43 const base::Closure& user_task) {
44 posted_from_ = posted_from;
45 delay_ = delay;
46 user_task_ = user_task;
47 Reset();
48 }
49
Reset()50 void TimedTaskHelper::Reset() {
51 DCHECK(task_runner_->RunsTasksOnCurrentThread());
52 DCHECK(!user_task_.is_null());
53 desired_run_time_ = base::TimeTicks::Now() + delay_;
54
55 if (tracker_)
56 return;
57
58 // Initialize the tracker for the first time.
59 tracker_ = new Tracker(this);
60 PostDelayedTask(make_scoped_ptr(tracker_), delay_);
61 }
62
63 // static
Fired(scoped_ptr<Tracker> tracker)64 void TimedTaskHelper::Fired(scoped_ptr<Tracker> tracker) {
65 if (!tracker->timer)
66 return;
67 TimedTaskHelper* timer = tracker->timer;
68 timer->OnFired(tracker.Pass());
69 }
70
OnFired(scoped_ptr<Tracker> tracker)71 void TimedTaskHelper::OnFired(scoped_ptr<Tracker> tracker) {
72 DCHECK(task_runner_->RunsTasksOnCurrentThread());
73 base::TimeTicks now = base::TimeTicks::Now();
74 if (desired_run_time_ > now) {
75 PostDelayedTask(tracker.Pass(), desired_run_time_ - now);
76 return;
77 }
78 tracker.reset();
79 base::Closure task = user_task_;
80 user_task_.Reset();
81 task.Run();
82 }
83
PostDelayedTask(scoped_ptr<Tracker> tracker,base::TimeDelta delay)84 void TimedTaskHelper::PostDelayedTask(scoped_ptr<Tracker> tracker,
85 base::TimeDelta delay) {
86 task_runner_->PostDelayedTask(
87 posted_from_,
88 base::Bind(&TimedTaskHelper::Fired, base::Passed(&tracker)),
89 delay);
90 }
91
92 } // namespace fileapi
93