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

Source/core/rendering/RenderFlowThread.h

Index: Source/core/rendering/RenderFlowThread.h
diff --git a/Source/core/rendering/RenderFlowThread.h b/Source/core/rendering/RenderFlowThread.h
deleted file mode 100644
index 27bfba903cc8ac05b1908c854fff27449a02143b..0000000000000000000000000000000000000000
--- a/Source/core/rendering/RenderFlowThread.h
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@@ -1,323 +0,0 @@
-/*
- * Copyright (C) 2011 Adobe Systems Incorporated. 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 THE COPYRIGHT HOLDER "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 THE COPYRIGHT HOLDER 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 RenderFlowThread_h
-#define RenderFlowThread_h
-
-
-#include "core/rendering/RenderBlockFlow.h"
-#include "wtf/HashCountedSet.h"
-#include "wtf/ListHashSet.h"
-#include "wtf/PassRefPtr.h"
-
-namespace WebCore {
-
-struct LayerFragment;
-typedef Vector<LayerFragment, 1> LayerFragments;
-class RenderFlowThread;
-class RenderStyle;
-class RenderRegion;
-
-typedef ListHashSet<RenderRegion*> RenderRegionList;
-
-// RenderFlowThread is used to collect all the render objects that participate in a
-// flow thread. It will also help in doing the layout. However, it will not render
-// directly to screen. Instead, RenderRegion objects will redirect their paint
-// and nodeAtPoint methods to this object. Each RenderRegion will actually be a viewPort
-// of the RenderFlowThread.
-
-class RenderFlowThread: public RenderBlockFlow {
-public:
-    RenderFlowThread();
-    virtual ~RenderFlowThread() { };
-
-    virtual bool isRenderFlowThread() const OVERRIDE FINAL { return true; }
-
-    virtual void layout() OVERRIDE FINAL;
-
-    // Always create a RenderLayer for the RenderFlowThread so that we
-    // can easily avoid drawing the children directly.
-    virtual LayerType layerTypeRequired() const OVERRIDE FINAL { return NormalLayer; }
-
-    virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction) OVERRIDE FINAL;
-
-    void removeFlowChildInfo(RenderObject*);
-#ifndef NDEBUG
-    bool hasChildInfo(RenderObject* child) const { return child && child->isBox() && m_regionRangeMap.contains(toRenderBox(child)); }
-#endif
-
-    virtual void addRegionToThread(RenderRegion*);
-    virtual void removeRegionFromThread(RenderRegion*);
-    const RenderRegionList& renderRegionList() const { return m_regionList; }
-
-    virtual void updateLogicalWidth() OVERRIDE FINAL;
-    virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const OVERRIDE;
-
-    void paintFlowThreadPortionInRegion(PaintInfo&, RenderRegion*, const LayoutRect& flowThreadPortionRect, const LayoutRect& flowThreadPortionOverflowRect, const LayoutPoint&) const;
-    bool hitTestFlowThreadPortionInRegion(RenderRegion*, const LayoutRect& flowThreadPortionRect, const LayoutRect& flowThreadPortionOverflowRect, const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset) const;
-
-    bool hasRegions() const { return m_regionList.size(); }
-    // Check if the content is flown into at least a region with region styling rules.
-    bool hasRegionsWithStyling() const { return m_hasRegionsWithStyling; }
-    void checkRegionsWithStyling();
-    virtual void regionChangedWritingMode(RenderRegion*) { }
-
-    void validateRegions();
-    void invalidateRegions();
-    bool hasValidRegionInfo() const { return !m_regionsInvalidated && !m_regionList.isEmpty(); }
-
-    static PassRefPtr<RenderStyle> createFlowThreadStyle(RenderStyle* parentStyle);
-
-    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) OVERRIDE;
-
-    void repaintRectangleInRegions(const LayoutRect&) const;
-
-    LayoutPoint adjustedPositionRelativeToOffsetParent(const RenderBoxModelObject&, const LayoutPoint&);
-
-    LayoutUnit pageLogicalTopForOffset(LayoutUnit);
-    LayoutUnit pageLogicalWidthForOffset(LayoutUnit);
-    LayoutUnit pageLogicalHeightForOffset(LayoutUnit);
-    LayoutUnit pageRemainingLogicalHeightForOffset(LayoutUnit, PageBoundaryRule = IncludePageBoundary);
-
-    virtual void setPageBreak(LayoutUnit /*offset*/, LayoutUnit /*spaceShortage*/) { }
-    virtual void updateMinimumPageHeight(LayoutUnit /*offset*/, LayoutUnit /*minHeight*/) { }
-
-    enum RegionAutoGenerationPolicy {
-        AllowRegionAutoGeneration,
-        DisallowRegionAutoGeneration,
-    };
-    RenderRegion* regionAtBlockOffset(LayoutUnit, bool extendLastRegion = false, RegionAutoGenerationPolicy = AllowRegionAutoGeneration);
-
-    RenderRegion* regionFromAbsolutePointAndBox(IntPoint, const RenderBox* flowedBox);
-
-    bool regionsHaveUniformLogicalWidth() const { return m_regionsHaveUniformLogicalWidth; }
-    bool regionsHaveUniformLogicalHeight() const { return m_regionsHaveUniformLogicalHeight; }
-
-    RenderRegion* mapFromFlowToRegion(TransformState&) const;
-
-    void removeRenderBoxRegionInfo(RenderBox*);
-    bool logicalWidthChangedInRegionsForBlock(const RenderBlock*);
-
-    LayoutUnit contentLogicalWidthOfFirstRegion() const;
-    LayoutUnit contentLogicalHeightOfFirstRegion() const;
-    LayoutUnit contentLogicalLeftOfFirstRegion() const;
-
-    RenderRegion* firstRegion() const;
-    RenderRegion* lastRegion() const;
-
-    bool previousRegionCountChanged() const { return m_previousRegionCount != m_regionList.size(); }
-    void updatePreviousRegionCount() { m_previousRegionCount = m_regionList.size(); }
-
-    void setRegionRangeForBox(const RenderBox*, LayoutUnit offsetFromLogicalTopOfFirstPage);
-    void getRegionRangeForBox(const RenderBox*, RenderRegion*& startRegion, RenderRegion*& endRegion) const;
-
-    void clearRenderObjectCustomStyle(const RenderObject*,
-        const RenderRegion* oldStartRegion = 0, const RenderRegion* oldEndRegion = 0,
-        const RenderRegion* newStartRegion = 0, const RenderRegion* newEndRegion = 0);
-
-    // Check if the object is in region and the region is part of this flow thread.
-    bool objectInFlowRegion(const RenderObject*, const RenderRegion*) const;
-
-    void markAutoLogicalHeightRegionsForLayout();
-
-    bool addForcedRegionBreak(LayoutUnit, RenderObject* breakChild, bool isBefore, LayoutUnit* offsetBreakAdjustment = 0);
-    void applyBreakAfterContent(LayoutUnit);
-
-    bool pageLogicalSizeChanged() const { return m_pageLogicalSizeChanged; }
-
-    bool hasAutoLogicalHeightRegions() const { ASSERT(isAutoLogicalHeightRegionsCountConsistent()); return m_autoLogicalHeightRegionsCount; }
-    void incrementAutoLogicalHeightRegions();
-    void decrementAutoLogicalHeightRegions();
-
-#ifndef NDEBUG
-    bool isAutoLogicalHeightRegionsCountConsistent() const;
-#endif
-
-    void collectLayerFragments(LayerFragments&, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRect);
-    LayoutRect fragmentsBoundingBox(const LayoutRect& layerBoundingBox);
-
-    void setInConstrainedLayoutPhase(bool value) { m_inConstrainedLayoutPhase = value; }
-    bool inConstrainedLayoutPhase() const { return m_inConstrainedLayoutPhase; }
-
-    bool needsTwoPhasesLayout() const { return m_needsTwoPhasesLayout; }
-    void clearNeedsTwoPhasesLayout() { m_needsTwoPhasesLayout = false; }
-
-    void pushFlowThreadLayoutState(const RenderObject*);
-    void popFlowThreadLayoutState();
-    LayoutUnit offsetFromLogicalTopOfFirstRegion(const RenderBlock*) const;
-
-    // Used to estimate the maximum height of the flow thread.
-    static LayoutUnit maxLogicalHeight() { return LayoutUnit::max() / 2; }
-
-protected:
-    virtual const char* renderName() const = 0;
-
-    // Overridden by columns/pages to set up an initial logical width of the page width even when
-    // no regions have been generated yet.
-    virtual LayoutUnit initialLogicalWidth() const { return 0; };
-
-    virtual void mapLocalToContainer(const RenderLayerModelObject* repaintContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = 0) const OVERRIDE FINAL;
-
-    void updateRegionsFlowThreadPortionRect(const RenderRegion* = 0);
-    bool shouldRepaint(const LayoutRect&) const;
-    bool regionInRange(const RenderRegion* targetRegion, const RenderRegion* startRegion, const RenderRegion* endRegion) const;
-
-    LayoutRect computeRegionClippingRect(const LayoutPoint&, const LayoutRect&, const LayoutRect&) const;
-
-    void setDispatchRegionLayoutUpdateEvent(bool value) { m_dispatchRegionLayoutUpdateEvent = value; }
-    bool shouldDispatchRegionLayoutUpdateEvent() { return m_dispatchRegionLayoutUpdateEvent; }
-
-    void setDispatchRegionOversetChangeEvent(bool value) { m_dispatchRegionOversetChangeEvent = value; }
-    bool shouldDispatchRegionOversetChangeEvent() const { return m_dispatchRegionOversetChangeEvent; }
-
-    // Override if the flow thread implementation supports dispatching events when the flow layout is updated (e.g. for named flows)
-    virtual void dispatchRegionLayoutUpdateEvent() { m_dispatchRegionLayoutUpdateEvent = false; }
-    virtual void dispatchRegionOversetChangeEvent() { m_dispatchRegionOversetChangeEvent = false; }
-
-    void initializeRegionsComputedAutoHeight(RenderRegion* = 0);
-
-    virtual void autoGenerateRegionsToBlockOffset(LayoutUnit) { };
-
-    bool cachedOffsetFromLogicalTopOfFirstRegion(const RenderBox*, LayoutUnit&) const;
-    void setOffsetFromLogicalTopOfFirstRegion(const RenderBox*, LayoutUnit);
-    void clearOffsetFromLogicalTopOfFirstRegion(const RenderBox*);
-
-    const RenderBox* currentStatePusherRenderBox() const;
-
-    RenderRegionList m_regionList;
-    unsigned short m_previousRegionCount;
-
-    class RenderRegionRange {
-    public:
-        RenderRegionRange()
-        {
-            setRange(0, 0);
-        }
-
-        RenderRegionRange(RenderRegion* start, RenderRegion* end)
-        {
-            setRange(start, end);
-        }
-
-        void setRange(RenderRegion* start, RenderRegion* end)
-        {
-            m_startRegion = start;
-            m_endRegion = end;
-        }
-
-        RenderRegion* startRegion() const { return m_startRegion; }
-        RenderRegion* endRegion() const { return m_endRegion; }
-
-    private:
-        RenderRegion* m_startRegion;
-        RenderRegion* m_endRegion;
-    };
-
-    typedef PODInterval<LayoutUnit, RenderRegion*> RegionInterval;
-    typedef PODIntervalTree<LayoutUnit, RenderRegion*> RegionIntervalTree;
-
-    class RegionSearchAdapter {
-    public:
-        RegionSearchAdapter(LayoutUnit offset)
-            : m_offset(offset)
-            , m_result(0)
-        {
-        }
-
-        const LayoutUnit& lowValue() const { return m_offset; }
-        const LayoutUnit& highValue() const { return m_offset; }
-        void collectIfNeeded(const RegionInterval&);
-
-        RenderRegion* result() const { return m_result; }
-
-    private:
-        LayoutUnit m_offset;
-        RenderRegion* m_result;
-    };
-
-    // A maps from RenderBox
-    typedef HashMap<const RenderBox*, RenderRegionRange> RenderRegionRangeMap;
-    RenderRegionRangeMap m_regionRangeMap;
-
-    typedef HashMap<RenderObject*, RenderRegion*> RenderObjectToRegionMap;
-    RenderObjectToRegionMap m_breakBeforeToRegionMap;
-    RenderObjectToRegionMap m_breakAfterToRegionMap;
-
-    // Stack of objects that pushed a LayoutState object on the RenderView. The
-    // objects on the stack are the ones that are curently in the process of being
-    // laid out.
-    ListHashSet<const RenderObject*> m_statePusherObjectsStack;
-    typedef HashMap<const RenderBox*, LayoutUnit> RenderBoxToOffsetMap;
-    RenderBoxToOffsetMap m_boxesToOffsetMap;
-
-    unsigned m_autoLogicalHeightRegionsCount;
-
-    RegionIntervalTree m_regionIntervalTree;
-
-    bool m_regionsInvalidated : 1;
-    bool m_regionsHaveUniformLogicalWidth : 1;
-    bool m_regionsHaveUniformLogicalHeight : 1;
-    bool m_hasRegionsWithStyling : 1;
-    bool m_dispatchRegionLayoutUpdateEvent : 1;
-    bool m_dispatchRegionOversetChangeEvent : 1;
-    bool m_pageLogicalSizeChanged : 1;
-    bool m_inConstrainedLayoutPhase : 1;
-    bool m_needsTwoPhasesLayout : 1;
-
-private:
-    virtual bool supportsPartialLayout() const OVERRIDE FINAL { return false; }
-
-};
-
-DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderFlowThread, isRenderFlowThread());
-
-class CurrentRenderFlowThreadMaintainer {
-    WTF_MAKE_NONCOPYABLE(CurrentRenderFlowThreadMaintainer);
-public:
-    CurrentRenderFlowThreadMaintainer(RenderFlowThread*);
-    ~CurrentRenderFlowThreadMaintainer();
-private:
-    RenderFlowThread* m_renderFlowThread;
-    RenderFlowThread* m_previousRenderFlowThread;
-};
-
-// These structures are used by PODIntervalTree for debugging.
-#ifndef NDEBUG
-template <> struct ValueToString<LayoutUnit> {
-    static String string(const LayoutUnit value) { return String::number(value.toFloat()); }
-};
-
-template <> struct ValueToString<RenderRegion*> {
-    static String string(const RenderRegion* value) { return String::format("%p", value); }
-};
-#endif
-
-} // namespace WebCore
-
-#endif // RenderFlowThread_h