/* * 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 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; #if PLATFORM(MAC) RetainPtr<CALayer> m_debugInfoLayer; #endif }; } // namespace WebCore #endif // ENABLE(THREADED_SCROLLING) #endif // ScrollingTree_h