third_party/WebKit/Source/core/frame/PlatformEventDispatcher.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/PlatformEventDispatcher.h"
   7
   8 #include "core/frame/PlatformEventController.h"
   9 #include "wtf/TemporaryChange.h"
  10
  11 namespace blink {
  12
  13 PlatformEventDispatcher::PlatformEventDispatcher()
  14     : m_isDispatching(false)
  15     , m_isListening(false)
  16 {
  17 }
  18
  19 void PlatformEventDispatcher::addController(PlatformEventController* controller)
  20 {
  21     ASSERT(controller);
  22     // TODO: If we can avoid to register a same controller twice, we can change
  23     // this 'if' to ASSERT.
  24     if (m_controllers.contains(controller))
  25         return;
  26
  27     m_controllers.add(controller);
  28
  29     if (!m_isListening) {
  30         startListening();
  31         m_isListening = true;
  32     }
  33 }
  34
  35 void PlatformEventDispatcher::removeController(PlatformEventController* controller)
  36 {
  37     ASSERT(m_controllers.contains(controller));
  38
  39     m_controllers.remove(controller);
  40     if (!m_isDispatching && m_controllers.isEmpty()) {
  41         stopListening();
  42         m_isListening = false;
  43     }
  44 }
  45
  46 void PlatformEventDispatcher::notifyControllers()
  47 {
  48     if (m_controllers.isEmpty())
  49         return;
  50
  51     {
  52         TemporaryChange<bool> changeIsDispatching(m_isDispatching, true);
  53         // HashSet m_controllers can be updated during an iteration, and it stops the iteration.
  54         // Thus we store it into a Vector to access all elements.
  55         WillBeHeapVector<RawPtrWillBeMember<PlatformEventController>> snapshotVector;
  56         copyToVector(m_controllers, snapshotVector);
  57         for (PlatformEventController* controller : snapshotVector) {
  58             if (m_controllers.contains(controller))
  59                 controller->didUpdateData();
  60         }
  61     }
  62
  63     if (m_controllers.isEmpty()) {
  64         stopListening();
  65         m_isListening = false;
  66     }
  67 }
  68
  69 DEFINE_TRACE(PlatformEventDispatcher)
  70 {
  71 #if ENABLE(OILPAN)
  72     visitor->trace(m_controllers);
  73 #endif
  74 }
  75
  76 } // namespace blink