third_party/WebKit/Source/core/frame/PlatformEventController.cpp

   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
  10 namespace blink {
  11
  12 PlatformEventController::PlatformEventController(Page* page)
  13     : PageLifecycleObserver(page)
  14     , m_hasEventListener(false)
  15     , m_isActive(false)
  16     , m_timer(this, &PlatformEventController::oneShotCallback)
  17 {
  18 }
  19
  20 PlatformEventController::~PlatformEventController()
  21 {
  22 }
  23
  24 void 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
  33 void 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
  47 void 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
  59 void 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