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 "config.h"
6#include "core/frame/PlatformEventController.h"
7
8#include "core/page/Page.h"
9
10namespace blink {
11
12PlatformEventController::PlatformEventController(Page* page)
13    : PageLifecycleObserver(page)
14    , m_hasEventListener(false)
15    , m_isActive(false)
16    , m_timer(this, &PlatformEventController::oneShotCallback)
17{
18}
19
20PlatformEventController::~PlatformEventController()
21{
22}
23
24void PlatformEventController::oneShotCallback(Timer<PlatformEventController>* timer)
25{
26    ASSERT_UNUSED(timer, timer == &m_timer);
27    ASSERT(hasLastData());
28    ASSERT(!m_timer.isActive());
29
30    didUpdateData();
31}
32
33void PlatformEventController::startUpdating()
34{
35    if (m_isActive)
36        return;
37
38    if (hasLastData() && !m_timer.isActive()) {
39        // Make sure to fire the data as soon as possible.
40        m_timer.startOneShot(0, FROM_HERE);
41    }
42
43    registerWithDispatcher();
44    m_isActive = true;
45}
46
47void PlatformEventController::stopUpdating()
48{
49    if (!m_isActive)
50        return;
51
52    if (m_timer.isActive())
53        m_timer.stop();
54
55    unregisterWithDispatcher();
56    m_isActive = false;
57}
58
59void PlatformEventController::pageVisibilityChanged()
60{
61    if (!m_hasEventListener)
62        return;
63
64    if (page()->visibilityState() == PageVisibilityStateVisible)
65        startUpdating();
66    else
67        stopUpdating();
68}
69
70} // namespace blink
71