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/*
* Copyright (C) 2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "FloatSize.h"
#include "ScrollTypes.h"
#include "Timer.h"
#include <wtf/RefPtr.h>
#include <wtf/WeakPtr.h>
#if ENABLE(WHEEL_EVENT_LATCHING)
namespace WTF {
class TextStream;
}
namespace WebCore {
class Element;
class LocalFrame;
class PlatformWheelEvent;
class ScrollableArea;
class ScrollLatchingController {
WTF_MAKE_FAST_ALLOCATED;
public:
ScrollLatchingController();
~ScrollLatchingController();
void clear();
void receivedWheelEvent(const PlatformWheelEvent&);
FloatSize cumulativeEventDelta() const { return m_cumulativeEventDelta; }
// Frame containing latched scroller (may be the frame or some sub-scroller).
LocalFrame* latchedFrame() const;
// Returns true if no frame is latched, or latching is in the given frame (in which case latchedScroller will be non-null).
bool latchingAllowsScrollingInFrame(const LocalFrame&, WeakPtr<ScrollableArea>& latchedScroller) const;
void updateAndFetchLatchingStateForFrame(LocalFrame&, const PlatformWheelEvent&, RefPtr<Element>& latchedElement, WeakPtr<ScrollableArea>&, bool& isOverWidget);
void removeLatchingStateForTarget(const Element&);
void removeLatchingStateForFrame(const LocalFrame&);
void dump(WTF::TextStream&) const;
private:
struct FrameState {
WeakPtr<Element, WeakPtrImplWithEventTargetData> wheelEventElement;
WeakPtr<ScrollableArea> scrollableArea;
LocalFrame* frame { nullptr };
bool isOverWidget { false };
};
void clearOrScheduleClearIfNeeded(const PlatformWheelEvent&);
void clearTimerFired();
bool hasStateForFrame(const LocalFrame&) const;
FrameState* stateForFrame(const LocalFrame&);
const FrameState* stateForFrame(const LocalFrame&) const;
bool shouldLatchToScrollableArea(const LocalFrame&, ScrollableArea*, FloatSize) const;
FloatSize m_cumulativeEventDelta;
Vector<FrameState> m_frameStateStack;
Timer m_clearLatchingStateTimer;
};
WTF::TextStream& operator<<(WTF::TextStream&, const ScrollLatchingController&);
} // namespace WebCore
#endif // ENABLE(WHEEL_EVENT_LATCHING)
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