*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/rendering/RenderNamedFlowThread.h

-/*
- * 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. ``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 COMPUTER, INC. OR
- * 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 RenderNamedFlowThread_h
-#define RenderNamedFlowThread_h
-
-#include "core/rendering/RenderFlowThread.h"
-#include "platform/Timer.h"
-#include "wtf/HashCountedSet.h"
-#include "wtf/ListHashSet.h"
-#include "wtf/text/AtomicString.h"
-
-namespace WebCore {
-
-class NamedFlow;
-class Node;
-class RenderNamedFlowThread;
-
-typedef ListHashSet<RenderNamedFlowThread*> RenderNamedFlowThreadList;
-typedef HashCountedSet<RenderNamedFlowThread*> RenderNamedFlowThreadCountedSet;
-typedef ListHashSet<Node*> NamedFlowContentNodes;
-
-class RenderNamedFlowThread FINAL : public RenderFlowThread {
-public:
-    virtual ~RenderNamedFlowThread();
-
-    static RenderNamedFlowThread* createAnonymous(Document*, PassRefPtr<NamedFlow>);
-
-    const AtomicString& flowThreadName() const;
-
-    const RenderRegionList& invalidRenderRegionList() const { return m_invalidRegionList; }
-
-    RenderObject* nextRendererForNode(Node*) const;
-    RenderObject* previousRendererForNode(Node*) const;
-
-    void addFlowChild(RenderObject* newChild);
-    void removeFlowChild(RenderObject*);
-    bool hasChildren() const { return !m_flowThreadChildList.isEmpty(); }
-#ifndef NDEBUG
-    bool hasChild(RenderObject* child) const { return m_flowThreadChildList.contains(child); }
-#endif
-
-    void pushDependencies(RenderNamedFlowThreadList&);
-
-    virtual void addRegionToThread(RenderRegion*) OVERRIDE;
-    virtual void removeRegionFromThread(RenderRegion*) OVERRIDE;
-
-    virtual void regionChangedWritingMode(RenderRegion*) OVERRIDE;
-
-    bool overset() const { return m_overset; }
-    void computeOversetStateForRegions(LayoutUnit oldClientAfterEdge);
-
-    void registerNamedFlowContentNode(Node*);
-    void unregisterNamedFlowContentNode(Node*);
-    const NamedFlowContentNodes& contentNodes() const { return m_contentNodes; }
-    bool hasContentNode(Node* contentNode) const { ASSERT(contentNode); return m_contentNodes.contains(contentNode); }
-    bool isMarkedForDestruction() const;
-    void getRanges(Vector<RefPtr<Range> >&, const RenderRegion*) const;
-
-protected:
-    void setMarkForDestruction();
-    void resetMarkForDestruction();
-
-private:
-    RenderNamedFlowThread(PassRefPtr<NamedFlow>);
-
-    virtual const char* renderName() const OVERRIDE;
-    virtual bool isRenderNamedFlowThread() const OVERRIDE { return true; }
-    virtual bool isChildAllowed(RenderObject*, RenderStyle*) const OVERRIDE;
-
-    virtual void dispatchRegionLayoutUpdateEvent() OVERRIDE;
-    virtual void dispatchRegionOversetChangeEvent() OVERRIDE;
-
-    bool dependsOn(RenderNamedFlowThread* otherRenderFlowThread) const;
-    void addDependencyOnFlowThread(RenderNamedFlowThread*);
-    void removeDependencyOnFlowThread(RenderNamedFlowThread*);
-
-    void addRegionToNamedFlowThread(RenderRegion*);
-
-    void checkInvalidRegions();
-
-    bool canBeDestroyed() const { return m_invalidRegionList.isEmpty() && m_regionList.isEmpty() && m_contentNodes.isEmpty(); }
-    void regionLayoutUpdateEventTimerFired(Timer<RenderNamedFlowThread>*);
-    void regionOversetChangeEventTimerFired(Timer<RenderNamedFlowThread>*);
-    void clearContentNodes();
-    void updateWritingMode();
-
-private:
-    // Observer flow threads have invalid regions that depend on the state of this thread
-    // to re-validate their regions. Keeping a set of observer threads make it easy
-    // to notify them when a region was removed from this flow.
-    RenderNamedFlowThreadCountedSet m_observerThreadsSet;
-
-    // Some threads need to have a complete layout before we layout this flow.
-    // That's because they contain a RenderRegion that should display this thread. The set makes it
-    // easy to sort the order of threads layout.
-    RenderNamedFlowThreadCountedSet m_layoutBeforeThreadsSet;
-
-    // Holds the sorted children of a named flow. This is the only way we can get the ordering right.
-    typedef ListHashSet<RenderObject*> FlowThreadChildList;
-    FlowThreadChildList m_flowThreadChildList;
-
-    NamedFlowContentNodes m_contentNodes;
-
-    RenderRegionList m_invalidRegionList;
-
-    bool m_overset : 1;
-
-    // The DOM Object that represents a named flow.
-    RefPtr<NamedFlow> m_namedFlow;
-
-    Timer<RenderNamedFlowThread> m_regionLayoutUpdateEventTimer;
-    Timer<RenderNamedFlowThread> m_regionOversetChangeEventTimer;
-};
-
-DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderNamedFlowThread, isRenderNamedFlowThread());
-
-} // namespace WebCore
-
-#endif // RenderNamedFlowThread_h
-