sky/engine/core/rendering/RenderObject.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
 * Copyright (C) 2009 Google Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef SKY_ENGINE_CORE_RENDERING_RENDEROBJECT_H_
#define SKY_ENGINE_CORE_RENDERING_RENDEROBJECT_H_

#include "sky/engine/core/dom/Document.h"
#include "sky/engine/core/dom/Element.h"
#include "sky/engine/core/editing/TextAffinity.h"
#include "sky/engine/core/html/HTMLElement.h"
#include "sky/engine/core/rendering/HitTestRequest.h"
#include "sky/engine/core/rendering/RenderObjectChildList.h"
#include "sky/engine/core/rendering/SubtreeLayoutScope.h"
#include "sky/engine/core/rendering/style/RenderStyle.h"
#include "sky/engine/core/rendering/style/StyleInheritedData.h"
#include "sky/engine/platform/geometry/FloatQuad.h"
#include "sky/engine/platform/geometry/LayoutRect.h"
#include "sky/engine/platform/transforms/TransformationMatrix.h"

namespace blink {

class AffineTransform;
class Document;
class HitTestLocation;
class HitTestResult;
class InlineBox;
class InlineFlowBox;
class Position;
class PositionWithAffinity;
class RenderBlock;
class RenderBox;
class RenderBoxModelObject;
class RenderGeometryMap;
class RenderLayer;
class RenderView;
class TransformState;

struct PaintInfo;

// Sides used when drawing borders and outlines. The values should run clockwise from top.
enum BoxSide {
    BSTop,
    BSRight,
    BSBottom,
    BSLeft
};

enum MarkingBehavior {
    MarkOnlyThis,
    MarkContainingBlockChain,
};

enum MapCoordinatesMode {
    UseTransforms = 1 << 0,
    // FIXME(sky): What is this for? Do we need it?
    ApplyContainerFlip = 1 << 1,
    // FIXME(sky): Remove
    TraverseDocumentBoundaries = 1 << 2,
};
typedef unsigned MapCoordinatesFlags;

const int caretWidth = 1;

struct AnnotatedRegionValue {
    bool operator==(const AnnotatedRegionValue& o) const
    {
        return draggable == o.draggable && bounds == o.bounds;
    }

    LayoutRect bounds;
    bool draggable;
};

typedef WTF::HashMap<const RenderLayer*, Vector<LayoutRect> > LayerHitTestRects;

#ifndef NDEBUG
const int showTreeCharacterOffset = 39;
#endif

// Base class for all rendering tree objects.
class RenderObject {
    friend class RenderBlock;
    friend class RenderObjectChildList;
    WTF_MAKE_NONCOPYABLE(RenderObject);
public:
    // TODO(ojan): Pass in a reference since the node can no longer be null.
    explicit RenderObject(Node*);
    virtual ~RenderObject();

    virtual const char* renderName() const = 0;

    String debugName() const;

    RenderObject* parent() const { return m_parent; }
    bool isDescendantOf(const RenderObject*) const;

    RenderObject* previousSibling() const { return m_previous; }
    RenderObject* nextSibling() const { return m_next; }

    RenderObject* slowFirstChild() const
    {
        if (const RenderObjectChildList* children = virtualChildren())
            return children->firstChild();
        return 0;
    }
    RenderObject* slowLastChild() const
    {
        if (const RenderObjectChildList* children = virtualChildren())
            return children->lastChild();
        return 0;
    }

    virtual RenderObjectChildList* virtualChildren() { return 0; }
    virtual const RenderObjectChildList* virtualChildren() const { return 0; }

    RenderObject* nextInPreOrder() const;
    RenderObject* nextInPreOrder(const RenderObject* stayWithin) const;
    RenderObject* nextInPreOrderAfterChildren() const;
    RenderObject* nextInPreOrderAfterChildren(const RenderObject* stayWithin) const;
    RenderObject* previousInPreOrder() const;
    RenderObject* previousInPreOrder(const RenderObject* stayWithin) const;
    RenderObject* childAt(unsigned) const;

    RenderObject* lastLeafChild() const;

    // The following six functions are used when the render tree hierarchy changes to make sure layers get
    // properly added and removed.  Since containership can be implemented by any subclass, and since a hierarchy
    // can contain a mixture of boxes and other object types, these functions need to be in the base class.
    RenderLayer* enclosingLayer() const;
    void addLayers(RenderLayer* parentLayer);
    void removeLayers(RenderLayer* parentLayer);
    void moveLayers(RenderLayer* oldParent, RenderLayer* newParent);
    RenderLayer* findNextLayer(RenderLayer* parentLayer, RenderObject* startPoint, bool checkParent = true);

    // Convenience function for getting to the nearest enclosing box of a RenderObject.
    RenderBox* enclosingBox() const;
    RenderBoxModelObject* enclosingBoxModelObject() const;

#if ENABLE(ASSERT)
    // Helper class forbidding calls to setNeedsLayout() during its lifetime.
    class SetLayoutNeededForbiddenScope {
    public:
        explicit SetLayoutNeededForbiddenScope(RenderObject&);
        ~SetLayoutNeededForbiddenScope();
    private:
        RenderObject& m_renderObject;
        bool m_preexistingForbidden;
    };

    void assertRendererLaidOut() const
    {
#ifndef NDEBUG
        if (needsLayout())
            showRenderTreeForThis();
#endif
        ASSERT_WITH_SECURITY_IMPLICATION(!needsLayout());
    }

    void assertSubtreeIsLaidOut() const
    {
        for (const RenderObject* renderer = this; renderer; renderer = renderer->nextInPreOrder())
            renderer->assertRendererLaidOut();
    }
#endif

    bool skipInvalidationWhenLaidOutChildren() const;

    // FIXME: This could be used when changing the size of a renderer without children to skip some invalidations.
    bool rendererHasNoBoxEffect() const
    {
        return !style()->hasVisualOverflowingEffect() && !style()->hasBorder() && !style()->hasBackground();
    }

    // Obtains the nearest enclosing block (including this block) that contributes a first-line style to our inline
    // children.
    virtual RenderBlock* firstLineBlock() const;

    // RenderObject tree manipulation
    //////////////////////////////////////////
    virtual bool canHaveChildren() const { return virtualChildren(); }
    virtual bool isChildAllowed(RenderObject*, RenderStyle*) const { return true; }
    virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0);
    virtual void removeChild(RenderObject*);
    //////////////////////////////////////////

protected:
    //////////////////////////////////////////
    // Helper functions. Dangerous to use!
    void setPreviousSibling(RenderObject* previous) { m_previous = previous; }
    void setNextSibling(RenderObject* next) { m_next = next; }
    void setParent(RenderObject* parent) { m_parent = parent; }

    //////////////////////////////////////////
private:
#if ENABLE(ASSERT)
    bool isSetNeedsLayoutForbidden() const { return m_setNeedsLayoutForbidden; }
    void setNeedsLayoutIsForbidden(bool flag) { m_setNeedsLayoutForbidden = flag; }
#endif

    void addAbsoluteRectForLayer(LayoutRect& result);

public:
#ifndef NDEBUG
    void showTreeForThis() const;
    void showRenderTreeForThis() const;
    void showLineTreeForThis() const;

    void showRenderObject() const;
    // We don't make printedCharacters an optional parameter so that
    // showRenderObject can be called from gdb easily.
    void showRenderObject(int printedCharacters) const;
    void showRenderTreeAndMark(const RenderObject* markedObject1 = 0, const char* markedLabel1 = 0, const RenderObject* markedObject2 = 0, const char* markedLabel2 = 0, int depth = 0) const;
#endif

    static RenderObject* createObject(Element*, RenderStyle*);
    static unsigned instanceCount() { return s_instanceCount; }

#if !ENABLE(OILPAN)
    // RenderObjects are allocated out of the rendering partition.
    void* operator new(size_t);
    void operator delete(void*);
#endif

public:
    virtual bool isBoxModelObject() const { return false; }
    virtual bool isCanvas() const { return false; }
    virtual bool isImage() const { return false; }
    virtual bool isInlineBlock() const { return false; }
    virtual bool isRenderBlock() const { return false; }
    virtual bool isRenderParagraph() const { return false; }
    virtual bool isRenderInline() const { return false; }
    virtual bool isRenderView() const { return false; }

    bool everHadLayout() const { return m_bitfields.everHadLayout(); }

    bool alwaysCreateLineBoxesForRenderInline() const
    {
        ASSERT(isRenderInline());
        return m_bitfields.alwaysCreateLineBoxesForRenderInline();
    }
    void setAlwaysCreateLineBoxesForRenderInline(bool alwaysCreateLineBoxes)
    {
        ASSERT(isRenderInline());
        m_bitfields.setAlwaysCreateLineBoxesForRenderInline(alwaysCreateLineBoxes);
    }

    bool ancestorLineBoxDirty() const { return m_bitfields.ancestorLineBoxDirty(); }
    void setAncestorLineBoxDirty(bool value = true)
    {
        m_bitfields.setAncestorLineBoxDirty(value);
        if (value)
            setNeedsLayout();
    }

    // SVG uses FloatPoint precise hit testing, and passes the point in parent
    // coordinates instead of in paint invalidaiton container coordinates. Eventually the
    // rest of the rendering tree will move to a similar model.
    virtual bool nodeAtFloatPoint(const HitTestRequest&, HitTestResult&, const FloatPoint& pointInParent);

    bool canHaveWhitespaceChildren() const
    {
        return !isFlexibleBox();
    }

    bool isOutOfFlowPositioned() const { return m_bitfields.isOutOfFlowPositioned(); } // absolute or fixed positioning
    bool isPositioned() const { return m_bitfields.isPositioned(); }

    bool isText() const  { return m_bitfields.isText(); }
    bool isBox() const { return m_bitfields.isBox(); }
    bool isInline() const { return m_bitfields.isInline(); } // inline object
    bool isDragging() const { return m_bitfields.isDragging(); }
    bool isReplaced() const { return m_bitfields.isReplaced(); } // a "replaced" element (see CSS)

    bool hasLayer() const { return m_bitfields.hasLayer(); }

    bool hasBoxDecorationBackground() const { return m_bitfields.hasBoxDecorationBackground(); }
    bool hasBackground() const { return style()->hasBackground(); }
    bool hasEntirelyFixedBackground() const;

    bool needsLayoutBecauseOfChildren() const { return needsLayout() && !selfNeedsLayout() && !needsPositionedMovementLayout() && !needsSimplifiedNormalFlowLayout(); }

    bool needsLayout() const
    {
        return m_bitfields.selfNeedsLayout() || m_bitfields.normalChildNeedsLayout() || m_bitfields.posChildNeedsLayout()
            || m_bitfields.needsSimplifiedNormalFlowLayout() || m_bitfields.needsPositionedMovementLayout();
    }

    bool selfNeedsLayout() const { return m_bitfields.selfNeedsLayout(); }
    bool needsPositionedMovementLayout() const { return m_bitfields.needsPositionedMovementLayout(); }
    bool needsPositionedMovementLayoutOnly() const
    {
        return m_bitfields.needsPositionedMovementLayout() && !m_bitfields.selfNeedsLayout() && !m_bitfields.normalChildNeedsLayout()
            && !m_bitfields.posChildNeedsLayout() && !m_bitfields.needsSimplifiedNormalFlowLayout();
    }

    bool posChildNeedsLayout() const { return m_bitfields.posChildNeedsLayout(); }
    bool needsSimplifiedNormalFlowLayout() const { return m_bitfields.needsSimplifiedNormalFlowLayout(); }
    bool normalChildNeedsLayout() const { return m_bitfields.normalChildNeedsLayout(); }

    bool preferredLogicalWidthsDirty() const { return m_bitfields.preferredLogicalWidthsDirty(); }

    bool needsOverflowRecalcAfterStyleChange() const { return m_bitfields.selfNeedsOverflowRecalcAfterStyleChange() || m_bitfields.childNeedsOverflowRecalcAfterStyleChange(); }
    bool selfNeedsOverflowRecalcAfterStyleChange() const { return m_bitfields.selfNeedsOverflowRecalcAfterStyleChange(); }
    bool childNeedsOverflowRecalcAfterStyleChange() const { return m_bitfields.childNeedsOverflowRecalcAfterStyleChange(); }

    bool isSelectionBorder() const;

    bool hasClip() const { return isOutOfFlowPositioned() && !style()->hasAutoClip(); }
    bool hasOverflowClip() const { return m_bitfields.hasOverflowClip(); }
    bool hasClipOrOverflowClip() const { return hasClip() || hasOverflowClip(); }

    bool hasTransform() const { return m_bitfields.hasTransform(); }
    bool hasClipPath() const { return style() && style()->clipPath(); }

    inline bool preservesNewline() const;

    RenderView* view() const { return document().renderView(); };
    FrameView* frameView() const { return document().view(); };

    bool isRooted() const;

    // TODO(ojan): Make this a reference now that it can't be null.
    Node* node() const
    {
        return m_node.get();
    }

    Document& document() const { return m_node->document(); }
    LocalFrame* frame() const { return document().frame(); }

    // Returns the object containing this one. Can be different from parent for positioned elements.
    // If paintInvalidationContainer and paintInvalidationContainerSkipped are not null, on return *paintInvalidationContainerSkipped
    // is true if the renderer returned is an ancestor of paintInvalidationContainer.
    RenderObject* container(const RenderBox* paintInvalidationContainer = 0, bool* paintInvalidationContainerSkipped = 0) const;

    Element* offsetParent() const;

    void markContainingBlocksForLayout(bool scheduleRelayout = true, RenderObject* newRoot = 0, SubtreeLayoutScope* = 0);
    void setNeedsLayout(MarkingBehavior = MarkContainingBlockChain, SubtreeLayoutScope* = 0);
    void clearNeedsLayout();
    void setChildNeedsLayout(MarkingBehavior = MarkContainingBlockChain, SubtreeLayoutScope* = 0);
    void setNeedsPositionedMovementLayout();
    void setPreferredLogicalWidthsDirty(MarkingBehavior = MarkContainingBlockChain);
    void clearPreferredLogicalWidthsDirty();
    void invalidateContainerPreferredLogicalWidths();

    void setNeedsLayoutAndPrefWidthsRecalc()
    {
        setNeedsLayout();
        setPreferredLogicalWidthsDirty();
    }

    void setPositionState(EPosition position)
    {
        ASSERT(position != AbsolutePosition || isBox());
        m_bitfields.setPositionedState(position);
    }
    void clearPositionedState() { m_bitfields.clearPositionedState(); }

    void setInline(bool isInline) { m_bitfields.setIsInline(isInline); }

    void setIsText() { m_bitfields.setIsText(true); }
    void setIsBox() { m_bitfields.setIsBox(true); }
    void setReplaced(bool isReplaced) { m_bitfields.setIsReplaced(isReplaced); }
    void setHasOverflowClip(bool hasOverflowClip) { m_bitfields.setHasOverflowClip(hasOverflowClip); }
    void setHasLayer(bool hasLayer) { m_bitfields.setHasLayer(hasLayer); }
    void setHasTransform(bool hasTransform) { m_bitfields.setHasTransform(hasTransform); }
    void setHasBoxDecorationBackground(bool b) { m_bitfields.setHasBoxDecorationBackground(b); }

    void scheduleRelayout();

    void updateFillImages(const FillLayer* oldLayers, const FillLayer& newLayers);
    void updateImage(StyleImage*, StyleImage*);

    // paintOffset is the offset from the origin of the GraphicsContext at which to paint the current object.
    virtual void paint(PaintInfo&, const LayoutPoint& paintOffset, Vector<RenderBox*>& layers);

    // Subclasses must reimplement this method to compute the size and position
    // of this object and all its descendants.
    virtual void layout() = 0;

    /* This function performs a layout only if one is needed. */
    void layoutIfNeeded() { if (needsLayout()) layout(); }

    void forceLayout();
    void forceChildLayout();

    bool hitTest(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset);
    virtual void updateHitTestResult(HitTestResult&, const LayoutPoint&);
    virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset);

    virtual PositionWithAffinity positionForPoint(const LayoutPoint&);
    PositionWithAffinity createPositionWithAffinity(int offset, EAffinity);
    PositionWithAffinity createPositionWithAffinity(const Position&);

    virtual void dirtyLinesFromChangedChild(RenderObject*);

    // Set the style of the object and update the state of the object accordingly.
    void setStyle(PassRefPtr<RenderStyle>);

    // Updates only the local style ptr of the object.  Does not update the state of the object,
    // and so only should be called when the style is known not to have changed (or from setStyle).
    void setStyleInternal(PassRefPtr<RenderStyle> style) { m_style = style; }

    // returns the containing block level element for this element.
    RenderBlock* containingBlock() const;

    // Convert the given local point to absolute coordinates
    // FIXME: Temporary. If UseTransforms is true, take transforms into account. Eventually localToAbsolute() will always be transform-aware.
    FloatPoint localToAbsolute(const FloatPoint& localPoint = FloatPoint(), MapCoordinatesFlags = 0) const;
    FloatPoint absoluteToLocal(const FloatPoint&, MapCoordinatesFlags = 0) const;

    // Convert a local quad to absolute coordinates, taking transforms into account.
    FloatQuad localToAbsoluteQuad(const FloatQuad& quad, MapCoordinatesFlags mode = 0) const
    {
        return localToContainerQuad(quad, 0, mode);
    }
    // Convert an absolute quad to local coordinates.
    FloatQuad absoluteToLocalQuad(const FloatQuad&, MapCoordinatesFlags mode = 0) const;

    // Convert a local quad into the coordinate system of container, taking transforms into account.
    FloatQuad localToContainerQuad(const FloatQuad&, const RenderBox* paintInvalidatinoContainer, MapCoordinatesFlags = 0) const;
    FloatPoint localToContainerPoint(const FloatPoint&, const RenderBox* paintInvalidationContainer, MapCoordinatesFlags = 0) const;

    // Return the offset from the container() renderer (excluding transforms). In multi-column layout,
    // different offsets apply at different points, so return the offset that applies to the given point.
    virtual LayoutSize offsetFromContainer(const RenderObject*, const LayoutPoint&, bool* offsetDependsOnPoint = 0) const;
    // Return the offset from an object up the container() chain. Asserts that none of the intermediate objects have transforms.
    LayoutSize offsetFromAncestorContainer(const RenderObject*) const;

    IntRect absoluteBoundingBoxRect() const;

    // Build an array of quads in absolute coords for line boxes
    virtual void absoluteQuads(Vector<FloatQuad>&) const { }

    virtual void absoluteFocusRingQuads(Vector<FloatQuad>&);

    static FloatRect absoluteBoundingBoxRectForRange(const Range*);

    virtual LayoutUnit minPreferredLogicalWidth() const { return 0; }
    virtual LayoutUnit maxPreferredLogicalWidth() const { return 0; }

    RenderStyle* style() const { return m_style.get(); }

    /* The two following methods are inlined in RenderObjectInlines.h */
    RenderStyle* firstLineStyle() const;
    RenderStyle* style(bool firstLine) const;

    inline Color resolveColor(const RenderStyle* styleToUse, int colorProperty) const
    {
        return styleToUse->colorIncludingFallback(colorProperty);
    }

    inline Color resolveColor(int colorProperty) const
    {
        return style()->colorIncludingFallback(colorProperty);
    }

    struct AppliedTextDecoration {
        Color color;
        TextDecorationStyle style;
        AppliedTextDecoration() : color(Color::transparent), style(TextDecorationStyleSolid) { }
    };

    void getTextDecorations(unsigned decorations, AppliedTextDecoration& underline, AppliedTextDecoration& overline, AppliedTextDecoration& linethrough, bool quirksMode = false, bool firstlineStyle = false);

    // Return the RenderBox in the container chain which is responsible for painting this object, or 0
    // if painting is root-relative. This is the container that should be passed to the 'forPaintInvalidation'
    // methods.
    const RenderView* containerForPaintInvalidation() const;
    const RenderBox* adjustCompositedContainerForSpecialAncestors(const RenderBox* paintInvalidationContainer) const;

    // Overriden by RenderText for character length, used in line layout code.
    virtual unsigned length() const { return 1; }

    // FIXME(sky): Remove
    bool isFloatingOrOutOfFlowPositioned() const { return isOutOfFlowPositioned(); }

    bool isTransparent() const { return style()->hasOpacity(); }
    float opacity() const { return style()->opacity(); }

    enum SelectionState {
        SelectionNone, // The object is not selected.
        SelectionStart, // The object either contains the start of a selection run or is the start of a run
        SelectionInside, // The object is fully encompassed by a selection run
        SelectionEnd, // The object either contains the end of a selection run or is the end of a run
        SelectionBoth // The object contains an entire run or is the sole selected object in that run
    };

    // The current selection state for an object.  For blocks, the state refers to the state of the leaf
    // descendants (as described above in the SelectionState enum declaration).
    SelectionState selectionState() const { return m_bitfields.selectionState(); }
    virtual void setSelectionState(SelectionState state) { m_bitfields.setSelectionState(state); }
    inline void setSelectionStateIfNeeded(SelectionState);
    bool canUpdateSelectionOnRootLineBoxes();

    virtual bool canBeSelectionLeaf() const { return false; }
    bool hasSelectedChildren() const { return selectionState() != SelectionNone; }

    bool isSelectable() const;
    // Obtains the selection colors that should be used when painting a selection.
    Color selectionBackgroundColor() const;
    Color selectionForegroundColor() const;
    Color selectionEmphasisMarkColor() const;

    // Whether or not a given block needs to paint selection gaps.
    virtual bool shouldPaintSelectionGaps() const { return false; }

    /**
     * Returns the local coordinates of the caret within this render object.
     * @param caretOffset zero-based offset determining position within the render object.
     * @param extraWidthToEndOfLine optional out arg to give extra width to end of line -
     * useful for character range rect computations
     */
    virtual LayoutRect localCaretRect(InlineBox*, int caretOffset, LayoutUnit* extraWidthToEndOfLine = 0);

    // When performing a global document tear-down, the renderer of the document is cleared. We use this
    // as a hook to detect the case of document destruction and don't waste time doing unnecessary work.
    bool documentBeingDestroyed() const;

    virtual void destroy();

    // Virtual function helper for the new FlexibleBox Layout (display: -webkit-flex).
    virtual bool isFlexibleBox() const { return false; }

    virtual int caretMinOffset() const;
    virtual int caretMaxOffset() const;

    virtual int previousOffset(int current) const;
    virtual int previousOffsetForBackwardDeletion(int current) const;
    virtual int nextOffset(int current) const;

    void selectionStartEnd(int& spos, int& epos) const;

    void remove() { if (parent()) parent()->removeChild(this); }

    bool supportsTouchAction() const;

    bool visibleToHitTestRequest(const HitTestRequest& request) const { return (request.ignorePointerEventsNone() || style()->pointerEvents() != PE_NONE); }

    bool visibleToHitTesting() const { return style()->pointerEvents() != PE_NONE; }

    // Map points and quads through elements, potentially via 3d transforms. You should never need to call these directly; use
    // localToAbsolute/absoluteToLocal methods instead.
    virtual void mapLocalToContainer(const RenderBox* paintInvalidationContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip) const;
    virtual void mapAbsoluteToLocalPoint(MapCoordinatesFlags, TransformState&) const;

    // Pushes state onto RenderGeometryMap about how to map coordinates from this renderer to its container, or ancestorToStopAt (whichever is encountered first).
    // Returns the renderer which was mapped to (container or ancestorToStopAt).
    virtual const RenderObject* pushMappingToContainer(const RenderBox* ancestorToStopAt, RenderGeometryMap&) const;

    bool shouldUseTransformFromContainer(const RenderObject* container) const;
    void getTransformFromContainer(const RenderObject* container, const LayoutSize& offsetInContainer, TransformationMatrix&) const;

    bool createsGroup() const { return isTransparent() || style()->hasFilter(); }

    virtual void addFocusRingRects(Vector<IntRect>&, const LayoutPoint& /* additionalOffset */, const RenderBox* /* paintContainer */ = 0) const { };

    RespectImageOrientationEnum shouldRespectImageOrientation() const;

    bool onlyNeededPositionedMovementLayout() const { return m_bitfields.onlyNeededPositionedMovementLayout(); }
    void setOnlyNeededPositionedMovementLayout(bool b) { m_bitfields.setOnlyNeededPositionedMovementLayout(b); }

    bool neededLayoutBecauseOfChildren() const { return m_bitfields.neededLayoutBecauseOfChildren(); }
    void setNeededLayoutBecauseOfChildren(bool b) { m_bitfields.setNeededLayoutBecauseOfChildren(b); }

    void setNeedsOverflowRecalcAfterStyleChange();
    void markContainingBlocksForOverflowRecalc();

protected:
    // Overrides should call the superclass at the end. m_style will be 0 the first time
    // this function will be called.
    virtual void styleWillChange(StyleDifference, const RenderStyle& newStyle);
    // Overrides should call the superclass at the start. |oldStyle| will be 0 the first
    // time this function is called.
    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle);

    void drawLineForBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2, BoxSide,
                            Color, EBorderStyle, int adjbw1, int adjbw2, bool antialias = false);
    void drawDashedOrDottedBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
        BoxSide, Color, int thickness, EBorderStyle, bool antialias);
    void drawDoubleBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
        int length, BoxSide, Color, int thickness, int adjacentWidth1, int adjacentWidth2, bool antialias);
    void drawRidgeOrGrooveBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
        BoxSide, Color, EBorderStyle, int adjacentWidth1, int adjacentWidth2, bool antialias);
    void drawSolidBoxSide(GraphicsContext*, int x1, int y1, int x2, int y2,
        BoxSide, Color, int adjacentWidth1, int adjacentWidth2, bool antialias);

    void paintFocusRing(PaintInfo&, const LayoutPoint&, RenderStyle*);
    void paintOutline(PaintInfo&, const LayoutRect&);
    void addChildFocusRingRects(Vector<IntRect>&, const LayoutPoint& additionalOffset, const RenderBox* paintContainer) const;

    virtual LayoutRect viewRect() const;

    void clearLayoutRootIfNeeded() const;
    virtual void willBeDestroyed();
    void postDestroy();

    void insertedIntoTree();
    void willBeRemovedFromTree();

private:
    bool hasImmediateNonWhitespaceTextChildOrPropertiesDependentOnColor() const;

    StyleDifference adjustStyleDifference(StyleDifference) const;

    Color selectionColor(int colorProperty) const;

#if ENABLE(ASSERT)
    void checkBlockPositionedObjectsNeedLayout();
#endif

    // FIXME(sky): This method is just to avoid copy-paste.
    // Merge container into containingBlock and then get rid of this method.
    bool canContainAbsolutePositionObjects() const
    {
        return isRenderView() || (hasTransform() && isRenderBlock());
    }

    static bool isAllowedToModifyRenderTreeStructure(Document&);

    RefPtr<RenderStyle> m_style;

    RawPtr<Node> m_node;

    RawPtr<RenderObject> m_parent;
    RawPtr<RenderObject> m_previous;
    RawPtr<RenderObject> m_next;

#if ENABLE(ASSERT)
    unsigned m_setNeedsLayoutForbidden : 1;
#if ENABLE(OILPAN)
protected:
    unsigned m_didCallDestroy          : 1;
private:
#endif
#endif

#define ADD_BOOLEAN_BITFIELD(name, Name) \
    private:\
        unsigned m_##name : 1;\
    public:\
        bool name() const { return m_##name; }\
        void set##Name(bool name) { m_##name = name; }\

    class RenderObjectBitfields {
        // FIXME(sky): Remove this enum and just use EPosition directly.
        enum PositionedState {
            IsStaticallyPositioned = 0,
            IsOutOfFlowPositioned = 1,
        };

    public:
        RenderObjectBitfields(Node* node)
            : m_selfNeedsLayout(false)
            , m_onlyNeededPositionedMovementLayout(false)
            , m_neededLayoutBecauseOfChildren(false)
            , m_needsPositionedMovementLayout(false)
            , m_normalChildNeedsLayout(false)
            , m_posChildNeedsLayout(false)
            , m_needsSimplifiedNormalFlowLayout(false)
            , m_preferredLogicalWidthsDirty(false)
            , m_selfNeedsOverflowRecalcAfterStyleChange(false)
            , m_childNeedsOverflowRecalcAfterStyleChange(false)
            , m_isText(false)
            , m_isBox(false)
            , m_isInline(true)
            , m_isReplaced(false)
            , m_isDragging(false)
            , m_hasLayer(false)
            , m_hasOverflowClip(false)
            , m_hasTransform(false)
            , m_hasBoxDecorationBackground(false)
            , m_everHadLayout(false)
            , m_ancestorLineBoxDirty(false)
            , m_alwaysCreateLineBoxesForRenderInline(false)
            , m_positionedState(IsStaticallyPositioned)
            , m_selectionState(SelectionNone)
        {
        }

        // 32 bits have been used in the first word, and 11 in the second.
        ADD_BOOLEAN_BITFIELD(selfNeedsLayout, SelfNeedsLayout);
        ADD_BOOLEAN_BITFIELD(onlyNeededPositionedMovementLayout, OnlyNeededPositionedMovementLayout);
        ADD_BOOLEAN_BITFIELD(neededLayoutBecauseOfChildren, NeededLayoutBecauseOfChildren);
        ADD_BOOLEAN_BITFIELD(needsPositionedMovementLayout, NeedsPositionedMovementLayout);
        ADD_BOOLEAN_BITFIELD(normalChildNeedsLayout, NormalChildNeedsLayout);
        ADD_BOOLEAN_BITFIELD(posChildNeedsLayout, PosChildNeedsLayout);
        ADD_BOOLEAN_BITFIELD(needsSimplifiedNormalFlowLayout, NeedsSimplifiedNormalFlowLayout);
        ADD_BOOLEAN_BITFIELD(preferredLogicalWidthsDirty, PreferredLogicalWidthsDirty);
        ADD_BOOLEAN_BITFIELD(selfNeedsOverflowRecalcAfterStyleChange, SelfNeedsOverflowRecalcAfterStyleChange);
        ADD_BOOLEAN_BITFIELD(childNeedsOverflowRecalcAfterStyleChange, ChildNeedsOverflowRecalcAfterStyleChange);

        ADD_BOOLEAN_BITFIELD(isText, IsText);
        ADD_BOOLEAN_BITFIELD(isBox, IsBox);
        ADD_BOOLEAN_BITFIELD(isInline, IsInline);
        ADD_BOOLEAN_BITFIELD(isReplaced, IsReplaced);
        ADD_BOOLEAN_BITFIELD(isDragging, IsDragging);

        ADD_BOOLEAN_BITFIELD(hasLayer, HasLayer);
        ADD_BOOLEAN_BITFIELD(hasOverflowClip, HasOverflowClip); // Set in the case of overflow:auto/scroll/hidden
        ADD_BOOLEAN_BITFIELD(hasTransform, HasTransform);
        ADD_BOOLEAN_BITFIELD(hasBoxDecorationBackground, HasBoxDecorationBackground);

        ADD_BOOLEAN_BITFIELD(everHadLayout, EverHadLayout);
        ADD_BOOLEAN_BITFIELD(ancestorLineBoxDirty, AncestorLineBoxDirty);

        // from RenderInline
        ADD_BOOLEAN_BITFIELD(alwaysCreateLineBoxesForRenderInline, AlwaysCreateLineBoxesForRenderInline);

    private:
        unsigned m_positionedState : 1; // PositionedState
        unsigned m_selectionState : 3; // SelectionState

    public:
        bool isOutOfFlowPositioned() const { return m_positionedState == IsOutOfFlowPositioned; }
        bool isPositioned() const { return m_positionedState != IsStaticallyPositioned; }

        void setPositionedState(int positionState)
        {
            m_positionedState = static_cast<PositionedState>(positionState);
        }
        void clearPositionedState() { m_positionedState = StaticPosition; }

        ALWAYS_INLINE SelectionState selectionState() const { return static_cast<SelectionState>(m_selectionState); }
        ALWAYS_INLINE void setSelectionState(SelectionState selectionState) { m_selectionState = selectionState; }
    };

#undef ADD_BOOLEAN_BITFIELD

    RenderObjectBitfields m_bitfields;

    void setSelfNeedsLayout(bool b) { m_bitfields.setSelfNeedsLayout(b); }
    void setNeedsPositionedMovementLayout(bool b) { m_bitfields.setNeedsPositionedMovementLayout(b); }
    void setNormalChildNeedsLayout(bool b) { m_bitfields.setNormalChildNeedsLayout(b); }
    void setPosChildNeedsLayout(bool b) { m_bitfields.setPosChildNeedsLayout(b); }
    void setNeedsSimplifiedNormalFlowLayout(bool b) { m_bitfields.setNeedsSimplifiedNormalFlowLayout(b); }
    void setIsDragging(bool b) { m_bitfields.setIsDragging(b); }
    void setEverHadLayout(bool b) { m_bitfields.setEverHadLayout(b); }
    void setSelfNeedsOverflowRecalcAfterStyleChange(bool b) { m_bitfields.setSelfNeedsOverflowRecalcAfterStyleChange(b); }
    void setChildNeedsOverflowRecalcAfterStyleChange(bool b) { m_bitfields.setChildNeedsOverflowRecalcAfterStyleChange(b); }

private:
    // Store state between styleWillChange and styleDidChange
    static bool s_affectsParentBlock;

    static unsigned s_instanceCount;
};

// Allow equality comparisons of RenderObjects by reference or pointer, interchangeably.
DEFINE_COMPARISON_OPERATORS_WITH_REFERENCES(RenderObject)

inline bool RenderObject::documentBeingDestroyed() const
{
    return !document().isActive();
}

// setNeedsLayout() won't cause full paint invalidations as
// setNeedsLayout() does. Otherwise the two methods are identical.
inline void RenderObject::setNeedsLayout(MarkingBehavior markParents, SubtreeLayoutScope* layouter)
{
    ASSERT(!isSetNeedsLayoutForbidden());
    bool alreadyNeededLayout = m_bitfields.selfNeedsLayout();
    setSelfNeedsLayout(true);
    if (!alreadyNeededLayout) {
        if (markParents == MarkContainingBlockChain && (!layouter || layouter->root() != this))
            markContainingBlocksForLayout(true, 0, layouter);
    }
}

inline void RenderObject::clearNeedsLayout()
{
    setOnlyNeededPositionedMovementLayout(needsPositionedMovementLayoutOnly());
    setNeededLayoutBecauseOfChildren(needsLayoutBecauseOfChildren());
    setSelfNeedsLayout(false);
    setEverHadLayout(true);
    setPosChildNeedsLayout(false);
    setNeedsSimplifiedNormalFlowLayout(false);
    setNormalChildNeedsLayout(false);
    setNeedsPositionedMovementLayout(false);
    setAncestorLineBoxDirty(false);
#if ENABLE(ASSERT)
    checkBlockPositionedObjectsNeedLayout();
#endif
}

inline void RenderObject::setChildNeedsLayout(MarkingBehavior markParents, SubtreeLayoutScope* layouter)
{
    ASSERT(!isSetNeedsLayoutForbidden());
    bool alreadyNeededLayout = normalChildNeedsLayout();
    setNormalChildNeedsLayout(true);
    // FIXME: Replace MarkOnlyThis with the SubtreeLayoutScope code path and remove the MarkingBehavior argument entirely.
    if (!alreadyNeededLayout && markParents == MarkContainingBlockChain && (!layouter || layouter->root() != this))
        markContainingBlocksForLayout(true, 0, layouter);
}

inline void RenderObject::setNeedsPositionedMovementLayout()
{
    bool alreadyNeededLayout = needsPositionedMovementLayout();
    setNeedsPositionedMovementLayout(true);
    ASSERT(!isSetNeedsLayoutForbidden());
    if (!alreadyNeededLayout)
        markContainingBlocksForLayout();
}

inline bool RenderObject::preservesNewline() const
{
    return style()->preserveNewline();
}

inline void RenderObject::setSelectionStateIfNeeded(SelectionState state)
{
    if (selectionState() == state)
        return;

    setSelectionState(state);
}

#define DEFINE_RENDER_OBJECT_TYPE_CASTS(thisType, predicate) \
    DEFINE_TYPE_CASTS(thisType, RenderObject, object, object->predicate, object.predicate)

} // namespace blink

#ifndef NDEBUG
// Outside the WebCore namespace for ease of invocation from gdb.
void showTree(const blink::RenderObject*);
void showLineTree(const blink::RenderObject*);
void showRenderTree(const blink::RenderObject* object1);
// We don't make object2 an optional parameter so that showRenderTree
// can be called from gdb easily.
void showRenderTree(const blink::RenderObject* object1, const blink::RenderObject* object2);

#endif

#endif  // SKY_ENGINE_CORE_RENDERING_RENDEROBJECT_H_