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/*
* Copyright (C) 2014-2017 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
#if ENABLE(ASYNC_SCROLLING)
#include "ScrollingStateTree.h"
#include "ScrollingTree.h"
#include <wtf/Condition.h>
#include <wtf/RefPtr.h>
namespace WebCore {
class AsyncScrollingCoordinator;
// The ThreadedScrollingTree 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 ThreadedScrollingTree : public ScrollingTree {
public:
virtual ~ThreadedScrollingTree();
void commitTreeState(std::unique_ptr<ScrollingStateTree>) override;
ScrollingEventResult handleWheelEvent(const PlatformWheelEvent&) override;
// 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.
ScrollingEventResult tryToHandleWheelEvent(const PlatformWheelEvent&) override;
void invalidate() override;
void incrementPendingCommitCount();
void decrementPendingCommitCount();
protected:
explicit ThreadedScrollingTree(AsyncScrollingCoordinator&);
void scrollingTreeNodeDidScroll(ScrollingTreeScrollingNode&, ScrollingLayerPositionAction = ScrollingLayerPositionAction::Sync) override;
#if PLATFORM(MAC)
void handleWheelEventPhase(PlatformWheelEventPhase) override;
void setActiveScrollSnapIndices(ScrollingNodeID, unsigned horizontalIndex, unsigned verticalIndex) override;
void deferWheelEventTestCompletionForReason(WheelEventTestMonitor::ScrollableAreaIdentifier, WheelEventTestMonitor::DeferReason) override;
void removeWheelEventTestCompletionDeferralForReason(WheelEventTestMonitor::ScrollableAreaIdentifier, WheelEventTestMonitor::DeferReason) override;
#endif
#if PLATFORM(COCOA)
void currentSnapPointIndicesDidChange(ScrollingNodeID, unsigned horizontal, unsigned vertical) override;
#endif
void reportExposedUnfilledArea(MonotonicTime, unsigned unfilledArea) override;
void reportSynchronousScrollingReasonsChanged(MonotonicTime, SynchronousScrollingReasons) override;
private:
bool isThreadedScrollingTree() const override { return true; }
void applyLayerPositions() override;
RefPtr<AsyncScrollingCoordinator> m_scrollingCoordinator;
void waitForPendingCommits();
Lock m_pendingCommitCountMutex;
unsigned m_pendingCommitCount { 0 };
Condition m_commitCondition;
};
} // namespace WebCore
SPECIALIZE_TYPE_TRAITS_SCROLLING_TREE(WebCore::ThreadedScrollingTree, isThreadedScrollingTree())
#endif // ENABLE(ASYNC_SCROLLING)