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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.
*/
#pragma once
#if ENABLE(ASYNC_SCROLLING)
#include "ScrollingStateNode.h"
#include <wtf/CheckedPtr.h>
#include <wtf/RefPtr.h>
#include <wtf/TZoneMalloc.h>
namespace WebCore {
class AsyncScrollingCoordinator;
class ScrollingStateFrameScrollingNode;
// The ScrollingStateTree is a tree that manages ScrollingStateNodes. The nodes keep track of the current
// state of scrolling related properties. Whenever any properties change, the scrolling coordinator
// will be informed and will schedule a timer that will clone the new state tree and send it over to
// the scrolling thread, avoiding locking.
class ScrollingStateTree final : public CanMakeCheckedPtr<ScrollingStateTree> {
WTF_MAKE_TZONE_ALLOCATED_EXPORT(ScrollingStateTree, WEBCORE_EXPORT);
WTF_OVERRIDE_DELETE_FOR_CHECKED_PTR(ScrollingStateTree);
friend class ScrollingStateNode;
public:
WEBCORE_EXPORT static std::optional<ScrollingStateTree> createAfterReconstruction(bool, bool, RefPtr<ScrollingStateFrameScrollingNode>&&);
WEBCORE_EXPORT ScrollingStateTree(AsyncScrollingCoordinator* = nullptr);
WEBCORE_EXPORT ScrollingStateTree(ScrollingStateTree&&);
WEBCORE_EXPORT ~ScrollingStateTree();
WEBCORE_EXPORT RefPtr<ScrollingStateFrameScrollingNode> rootStateNode() const;
WEBCORE_EXPORT RefPtr<ScrollingStateNode> stateNodeForID(std::optional<ScrollingNodeID>) const;
ScrollingNodeID createUnparentedNode(ScrollingNodeType, ScrollingNodeID);
WEBCORE_EXPORT std::optional<ScrollingNodeID> insertNode(ScrollingNodeType, ScrollingNodeID, std::optional<ScrollingNodeID> parentID, size_t childIndex);
void unparentNode(std::optional<ScrollingNodeID>);
void unparentChildrenAndDestroyNode(std::optional<ScrollingNodeID>);
void detachAndDestroySubtree(std::optional<ScrollingNodeID>);
void clear();
// Copies the current tree state and clears the changed properties mask in the original.
WEBCORE_EXPORT std::unique_ptr<ScrollingStateTree> commit(LayerRepresentation::Type preferredLayerRepresentation);
WEBCORE_EXPORT void attachDeserializedNodes();
WEBCORE_EXPORT void setHasChangedProperties(bool = true);
bool hasChangedProperties() const { return m_hasChangedProperties; }
bool hasNewRootStateNode() const { return m_hasNewRootStateNode; }
unsigned nodeCount() const { return m_stateNodeMap.size(); }
unsigned scrollingNodeCount() const { return m_scrollingNodeCount; }
using StateNodeMap = UncheckedKeyHashMap<ScrollingNodeID, Ref<ScrollingStateNode>>;
const StateNodeMap& nodeMap() const { return m_stateNodeMap; }
LayerRepresentation::Type preferredLayerRepresentation() const { return m_preferredLayerRepresentation; }
void setPreferredLayerRepresentation(LayerRepresentation::Type representation) { m_preferredLayerRepresentation = representation; }
void reconcileViewportConstrainedLayerPositions(std::optional<ScrollingNodeID>, const LayoutRect& viewportRect, ScrollingLayerPositionAction);
void scrollingNodeAdded()
{
++m_scrollingNodeCount;
}
void scrollingNodeRemoved()
{
ASSERT(m_scrollingNodeCount);
--m_scrollingNodeCount;
}
WEBCORE_EXPORT String scrollingStateTreeAsText(OptionSet<ScrollingStateTreeAsTextBehavior>) const;
FrameIdentifier rootFrameIdentifier() const { return *m_rootFrameIdentifier; }
void setRootFrameIdentifier(std::optional<FrameIdentifier> frameID) { m_rootFrameIdentifier = frameID; }
private:
ScrollingStateTree(bool hasNewRootStateNode, bool hasChangedProperties, RefPtr<ScrollingStateFrameScrollingNode>&&);
void setRootStateNode(Ref<ScrollingStateFrameScrollingNode>&&);
void addNode(ScrollingStateNode&);
Ref<ScrollingStateNode> createNode(ScrollingNodeType, ScrollingNodeID);
void removeNodeAndAllDescendants(ScrollingStateNode&);
void recursiveNodeWillBeRemoved(ScrollingStateNode&);
void willRemoveNode(ScrollingStateNode&);
bool isValid() const;
void traverse(const ScrollingStateNode&, NOESCAPE const Function<void(const ScrollingStateNode&)>&) const;
ThreadSafeWeakPtr<AsyncScrollingCoordinator> m_scrollingCoordinator;
Markable<FrameIdentifier> m_rootFrameIdentifier;
// Contains all the nodes we know about (those in the m_rootStateNode tree, and in m_unparentedNodes subtrees).
StateNodeMap m_stateNodeMap;
// Owns roots of unparented subtrees.
UncheckedKeyHashMap<ScrollingNodeID, RefPtr<ScrollingStateNode>> m_unparentedNodes;
RefPtr<ScrollingStateFrameScrollingNode> m_rootStateNode;
unsigned m_scrollingNodeCount { 0 };
LayerRepresentation::Type m_preferredLayerRepresentation { LayerRepresentation::GraphicsLayerRepresentation };
bool m_hasChangedProperties { false };
bool m_hasNewRootStateNode { false };
};
} // namespace WebCore
#ifndef NDEBUG
void showScrollingStateTree(const WebCore::ScrollingStateTree&);
void showScrollingStateTree(const WebCore::ScrollingStateNode&);
#endif
#endif // ENABLE(ASYNC_SCROLLING)
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