Source/core/dom/EventHandlerRegistry.h - Issue 237963014: Track scroll event handlers in nested documents

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Issue 237963014: Track scroll event handlers in nested documents (Closed) Base URL: svn://svn.chromium.org/blink/trunk

Patch Set: didMove{Into,OutOf}Page Created 6 years, 7 months ago

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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 EventHandlerRegistry_h

6 #define EventHandlerRegistry_h

7

8 #include "core/dom/DocumentSupplementable.h"

9 #include "core/events/Event.h"

10 #include "wtf/HashCountedSet.h"

11

12 namespace WebCore {

13

14 typedef HashCountedSet<EventTarget*> EventTargetSet;

15

16 // Registry for keeping track of event handlers. Handlers can either be

17 // associated with an EventTarget or be "external" handlers which live outside

18 // the DOM (e.g., WebViewImpl).

19 class EventHandlerRegistry FINAL : public DocumentSupplement {

20 public:

21 virtual ~EventHandlerRegistry();

22

23 // Supported event handler classes. Note that each one may correspond to

24 // multiple event types.

25 enum EventHandlerClass {

26 ScrollEvent,

27 EventHandlerClassCount, // Must be the last entry.

28 };

29

30 static const char* supplementName();

31 static EventHandlerRegistry* from(Document&);

32

33 // Returns true if the host Document or any child documents have any

34 // registered event handlers of the class.

35 bool hasEventHandlers(EventHandlerClass) const;

36

37 // Returns a set of EventTargets which have registered handlers of the

38 // given class. Only contains targets directly in this document; all

39 // handlers in a child Document are collapsed to a single respective

40 // Document instance in the set.

41 const EventTargetSet* eventHandlerTargets(EventHandlerClass) const;

42

43 // Registration and management of event handlers attached to EventTargets.

44 void didAddEventHandler(EventTarget&, const AtomicString& eventType);

45 void didAddEventHandler(EventTarget&, EventHandlerClass);

46 void didRemoveEventHandler(EventTarget&, const AtomicString& eventType);

47 void didRemoveEventHandler(EventTarget&, EventHandlerClass);

48 void didMoveFromOtherDocument(EventTarget&, Document& oldDocument);

49 void didRemoveAllEventHandlers(EventTarget&);

50

51 virtual void trace(Visitor*) OVERRIDE { }

52

53 private:

54 explicit EventHandlerRegistry(Document&);

55

56 enum ChangeOperation {

57 Add, // Add a new event handler.

58 Remove, // Remove an existing event handler.

59 RemoveAll // Remove any and all existing event handlers for a given targ et.

60 };

61

62 // Returns true if \|eventType\| belongs to a class this registry tracks.

63 static bool eventTypeToClass(const AtomicString& eventType, EventHandlerClas s* result);

64

65 // Returns true if the operation actually added a new target or completely

66 // removed an existing one.

67 bool updateEventHandlerTargets(ChangeOperation, EventHandlerClass, EventTarg et*);

68

69 // Called on the EventHandlerRegistry of the root Document to notify

70 // clients when we have added the first handler or removed the last one for

71 // a given event class. \|hasActiveHandlers\| can be used to distinguish

72 // between the two cases.

73 void notifyHasHandlersChanged(EventHandlerClass, bool hasActiveHandlers);

74

75 // Record a change operation to a given event handler class and notify any

76 // parent registry and other clients accordingly.

77 void updateEventHandlerOfType(ChangeOperation, const AtomicString& eventType , EventTarget*);

78

79 void updateEventHandlerInternal(ChangeOperation, EventHandlerClass, EventTar get*);

80

81 struct HandlerState {

82 HandlerState();

83 ~HandlerState();

84

85 OwnPtr<EventTargetSet> targets;

86 };

87

88 Document& m_document;

89 HandlerState m_eventHandlers[EventHandlerClassCount];

90 };

91

92 } // namespace WebCore

93

94 #endif // EventHandlerRegistry_h

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