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

   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 #ifndef PlatformEventController_h
   6 #define PlatformEventController_h
   7
   8 #include "core/CoreExport.h"
   9 #include "core/page/PageLifecycleObserver.h"
  10 #include "platform/Timer.h"
  11 #include "platform/heap/Handle.h"
  12
  13 namespace blink {
  14
  15 // Base controller class for registering controllers with a dispatcher.
  16 // It watches page visibility and calls stopUpdating when page is not visible.
  17 // It provides a didUpdateData() callback method which is called when new data
  18 // it available.
  19 class CORE_EXPORT PlatformEventController : public PageLifecycleObserver {
  20 public:
  21     void startUpdating();
  22     void stopUpdating();
  23
  24     // This is called when new data becomes available.
  25     virtual void didUpdateData() = 0;
  26
  27 protected:
  28     explicit PlatformEventController(Page*);
  29     virtual ~PlatformEventController();
  30
  31     virtual void registerWithDispatcher() = 0;
  32     virtual void unregisterWithDispatcher() = 0;
  33
  34     // When true initiates a one-shot didUpdateData() when startUpdating() is called.
  35     virtual bool hasLastData() = 0;
  36
  37     bool m_hasEventListener;
  38
  39 private:
  40     // Inherited from PageLifecycleObserver.
  41     void pageVisibilityChanged() override;
  42
  43     void oneShotCallback(Timer<PlatformEventController>*);
  44
  45     bool m_isActive;
  46     Timer<PlatformEventController> m_timer;
  47 };
  48
  49 } // namespace blink
  50
  51 #endif // PlatformEventController_h