Source/WebCore/page/scrolling/ios/ScrollingTreeIOS.cpp

/*
 * Copyright (C) 2014 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.
 */

#include "config.h"
#include "ScrollingTreeIOS.h"

#if ENABLE(ASYNC_SCROLLING)

#include "AsyncScrollingCoordinator.h"
#include "PlatformWheelEvent.h"
#include "ScrollingThread.h"
#include "ScrollingTreeFixedNode.h"
#include "ScrollingTreeFrameScrollingNodeIOS.h"
#include "ScrollingTreeNode.h"
#include "ScrollingTreeScrollingNode.h"
#include "ScrollingTreeStickyNode.h"
#include <wtf/MainThread.h>

namespace WebCore {

Ref<ScrollingTreeIOS> ScrollingTreeIOS::create(AsyncScrollingCoordinator* scrollingCoordinator)
{
    return adoptRef(*new ScrollingTreeIOS(scrollingCoordinator));
}

ScrollingTreeIOS::ScrollingTreeIOS(AsyncScrollingCoordinator* scrollingCoordinator)
    : m_scrollingCoordinator(scrollingCoordinator)
{
}

ScrollingTreeIOS::~ScrollingTreeIOS()
{
    // invalidate() should have cleared m_scrollingCoordinator.
    ASSERT(!m_scrollingCoordinator);
}

void ScrollingTreeIOS::invalidate()
{
    // Invalidate is dispatched by the ScrollingCoordinator class on the ScrollingThread
    // to break the reference cycle between ScrollingTree and ScrollingCoordinator when the
    // ScrollingCoordinator's page is destroyed.
    ASSERT(ScrollingThread::isCurrentThread());

    // Since this can potentially be the last reference to the scrolling coordinator,
    // we need to release it on the main thread since it has member variables (such as timers)
    // that expect to be destroyed from the main thread.
    callOnMainThread([scrollingCoordinator = WTFMove(m_scrollingCoordinator)] {
    });
}

void ScrollingTreeIOS::scrollingTreeNodeDidScroll(ScrollingNodeID nodeID, const FloatPoint& scrollPosition, const std::optional<FloatPoint>& layoutViewportOrigin, ScrollingLayerPositionAction scrollingLayerPositionAction)
{
    if (!m_scrollingCoordinator)
        return;

    if (nodeID == rootNode()->scrollingNodeID())
        setMainFrameScrollPosition(scrollPosition);

    callOnMainThread([scrollingCoordinator = m_scrollingCoordinator, nodeID, scrollPosition, layoutViewportOrigin, localIsHandlingProgrammaticScroll = isHandlingProgrammaticScroll(), scrollingLayerPositionAction] {
        scrollingCoordinator->scheduleUpdateScrollPositionAfterAsyncScroll(nodeID, scrollPosition, layoutViewportOrigin, localIsHandlingProgrammaticScroll, scrollingLayerPositionAction);
    });
}

PassRefPtr<ScrollingTreeNode> ScrollingTreeIOS::createScrollingTreeNode(ScrollingNodeType nodeType, ScrollingNodeID nodeID)
{
    switch (nodeType) {
    case FrameScrollingNode:
        return ScrollingTreeFrameScrollingNodeIOS::create(*this, nodeID);
    case OverflowScrollingNode:
        ASSERT_NOT_REACHED();
        return nullptr;
    case FixedNode:
        return ScrollingTreeFixedNode::create(*this, nodeID);
    case StickyNode:
        return ScrollingTreeStickyNode::create(*this, nodeID);
    }
    return nullptr;
}

FloatRect ScrollingTreeIOS::fixedPositionRect()
{
    // When ScrollingTreeIOS starts being used for WK1 on iOS, this needs to get the customFixedPositionRect from
    // the ScrollingCoordinator.
    ASSERT_NOT_REACHED();
    return FloatRect();
}

void ScrollingTreeIOS::currentSnapPointIndicesDidChange(WebCore::ScrollingNodeID nodeID, unsigned horizontal, unsigned vertical)
{
    if (!m_scrollingCoordinator)
        return;
    
    callOnMainThread([scrollingCoordinator = m_scrollingCoordinator, nodeID, horizontal, vertical] {
        scrollingCoordinator->setActiveScrollSnapIndices(nodeID, horizontal, vertical);
    });
}

} // namespace WebCore

#endif // ENABLE(ASYNC_SCROLLING)