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/*
* Copyright (C) 2012 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.
*/
#ifndef ScrollingTree_h
#define ScrollingTree_h
#if ENABLE(THREADED_SCROLLING)
#include "PlatformWheelEvent.h"
#include "Region.h"
#include <wtf/Functional.h>
#include <wtf/OwnPtr.h>
#include <wtf/PassOwnPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefPtr.h>
#include <wtf/ThreadSafeRefCounted.h>
#if PLATFORM(MAC)
#include <wtf/RetainPtr.h>
OBJC_CLASS CALayer;
#endif
namespace WebCore {
class IntPoint;
class ScrollingCoordinator;
class ScrollingTreeNode;
class ScrollingTreeState;
// The ScrollingTree class lives almost exclusively on the scrolling thread and manages the
// hierarchy of scrollable regions on the page. It's also responsible for dispatching events
// to the correct scrolling tree nodes or dispatching events back to the ScrollingCoordinator
// object on the main thread if they can't be handled on the scrolling thread for various reasons.
class ScrollingTree : public ThreadSafeRefCounted<ScrollingTree> {
public:
static PassRefPtr<ScrollingTree> create(ScrollingCoordinator*);
~ScrollingTree();
enum EventResult {
DidNotHandleEvent,
DidHandleEvent,
SendToMainThread
};
// Can be called from any thread. Will try to handle the wheel event on the scrolling thread.
// Returns true if the wheel event can be handled on the scrolling thread and false if the
// event must be sent again to the WebCore event handler.
EventResult tryToHandleWheelEvent(const PlatformWheelEvent&);
// Can be called from any thread. Will update the back forward state of the page, used for rubber-banding.
void updateBackForwardState(bool canGoBack, bool canGoForward);
// Must be called from the scrolling thread. Handles the wheel event.
void handleWheelEvent(const PlatformWheelEvent&);
void invalidate();
void commitNewTreeState(PassOwnPtr<ScrollingTreeState>);
void setMainFramePinState(bool pinnedToTheLeft, bool pinnedToTheRight);
void updateMainFrameScrollPosition(const IntPoint& scrollPosition);
void updateMainFrameScrollPositionAndScrollLayerPosition(const IntPoint& scrollPosition);
IntPoint mainFrameScrollPosition();
#if PLATFORM(MAC) || (PLATFORM(CHROMIUM) && OS(DARWIN))
void handleWheelEventPhase(PlatformWheelEventPhase);
#endif
bool canGoBack();
bool canGoForward();
bool willWheelEventStartSwipeGesture(const PlatformWheelEvent&);
#if PLATFORM(MAC)
void setDebugRootLayer(CALayer *);
#endif
void setScrollingPerformanceLoggingEnabled(bool flag);
bool scrollingPerformanceLoggingEnabled();
private:
explicit ScrollingTree(ScrollingCoordinator*);
void updateDebugRootLayer();
RefPtr<ScrollingCoordinator> m_scrollingCoordinator;
OwnPtr<ScrollingTreeNode> m_rootNode;
Mutex m_mutex;
Region m_nonFastScrollableRegion;
IntPoint m_mainFrameScrollPosition;
bool m_hasWheelEventHandlers;
Mutex m_swipeStateMutex;
bool m_canGoBack;
bool m_canGoForward;
bool m_mainFramePinnedToTheLeft;
bool m_mainFramePinnedToTheRight;
bool m_scrollingPerformanceLoggingEnabled;
#if PLATFORM(MAC)
RetainPtr<CALayer> m_debugInfoLayer;
#endif
};
} // namespace WebCore
#endif // ENABLE(THREADED_SCROLLING)
#endif // ScrollingTree_h
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