renderobject.h

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2000 Lars Knoll ([e-mail])
 *           (C) 2000 Antti Koivisto ([e-mail])
 *           (C) 2000 Dirk Mueller ([e-mail])
 *           (C) 2004 Allan Sandfeld Jensen ([e-mail])
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple 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 RenderObject_h
#define RenderObject_h

#include "CachedResourceClient.h"
#include "FloatQuad.h"
#include "Document.h"
#include "RenderObjectChildList.h"
#include "RenderStyle.h"
#include "TransformationMatrix.h"

namespace WebCore {

class AnimationController;
class HitTestResult;
class InlineBox;
class InlineFlowBox;
class RenderBoxModelObject;
class RenderInline;
class RenderBlock;
class RenderFlow;
class RenderLayer;
class TransformState;
class VisiblePosition;

/*
 *  The painting of a layer occurs in three distinct phases.  Each phase involves
 *  a recursive descent into the layer's render objects. The first phase is the background phase.
 *  The backgrounds and borders of all blocks are painted.  Inlines are not painted at all.
 *  Floats must paint above block backgrounds but entirely below inline content that can overlap them.
 *  In the foreground phase, all inlines are fully painted.  Inline replaced elements will get all
 *  three phases invoked on them during this phase.
 */

enum PaintPhase {
    PaintPhaseBlockBackground,
    PaintPhaseChildBlockBackground,
    PaintPhaseChildBlockBackgrounds,
    PaintPhaseFloat,
    PaintPhaseForeground,
    PaintPhaseOutline,
    PaintPhaseChildOutlines,
    PaintPhaseSelfOutline,
    PaintPhaseSelection,
    PaintPhaseCollapsedTableBorders,
    PaintPhaseTextClip,
    PaintPhaseMask
};

enum PaintRestriction {
    PaintRestrictionNone,
    PaintRestrictionSelectionOnly,
    PaintRestrictionSelectionOnlyBlackText
};

enum HitTestFilter {
    HitTestAll,
    HitTestSelf,
    HitTestDescendants
};

enum HitTestAction {
    HitTestBlockBackground,
    HitTestChildBlockBackground,
    HitTestChildBlockBackgrounds,
    HitTestFloat,
    HitTestForeground
};

// Sides used when drawing borders and outlines.  This is in RenderObject rather than RenderBoxModelObject since outlines can
// be drawn by SVG around bounding boxes.
enum BoxSide {
    BSTop,
    BSBottom,
    BSLeft,
    BSRight
};

const int caretWidth = 1;

#if ENABLE(DASHBOARD_SUPPORT)
struct DashboardRegionValue {
    bool operator==(const DashboardRegionValue& o) const
    {
        return type == o.type && bounds == o.bounds && clip == o.clip && label == o.label;
    }
    bool operator!=(const DashboardRegionValue& o) const
    {
        return !(*this == o);
    }

    String label;
    IntRect bounds;
    IntRect clip;
    int type;
};
#endif

// Base class for all rendering tree objects.
class RenderObject : public CachedResourceClient {
    friend class RenderBlock;
    friend class RenderBox;
    friend class RenderLayer;
    friend class RenderObjectChildList;
    friend class RenderSVGContainer;
public:
    // Anonymous objects should pass the document as their node, and they will then automatically be
    // marked as anonymous in the constructor.
    RenderObject(Node*);
    virtual ~RenderObject();

    virtual const char* renderName() const = 0;

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

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

    RenderObject* firstChild() const
    {
        if (const RenderObjectChildList* children = virtualChildren())
            return children->firstChild();
        return 0;
    }
    RenderObject* lastChild() 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(RenderObject* stayWithin) const;
    RenderObject* nextInPreOrderAfterChildren() const;
    RenderObject* nextInPreOrderAfterChildren(RenderObject* stayWithin) const;
    RenderObject* previousInPreOrder() const;
    RenderObject* childAt(unsigned) const;

    RenderObject* firstLeafChild() const;
    RenderObject* lastLeafChild() const;

    // The following five 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, RenderObject* newObject);
    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;
    
    virtual bool isEmpty() const { return firstChild() == 0; }

#ifndef NDEBUG
    void setHasAXObject(bool flag) { m_hasAXObject = flag; }
    bool hasAXObject() const { return m_hasAXObject; }
    bool isSetNeedsLayoutForbidden() const { return m_setNeedsLayoutForbidden; }
    void setNeedsLayoutIsForbidden(bool flag) { m_setNeedsLayoutForbidden = flag; }
#endif

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

    // Called when an object that was floating or positioned becomes a normal flow object
    // again.  We have to make sure the render tree updates as needed to accommodate the new
    // normal flow object.
    void handleDynamicFloatPositionChange();
    
    // 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 addChildIgnoringContinuation(RenderObject* newChild, RenderObject* beforeChild = 0) { return addChild(newChild, beforeChild); }
    virtual void removeChild(RenderObject*);
    virtual bool createsAnonymousWrapper() const { return false; }
    //////////////////////////////////////////

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:
    void addAbsoluteRectForLayer(IntRect& result);
    void setLayerNeedsFullRepaint();

public:
#ifndef NDEBUG
    void showTreeForThis() const;
#endif

    static RenderObject* createObject(Node*, RenderStyle*);

    // Overloaded new operator.  Derived classes must override operator new
    // in order to allocate out of the RenderArena.
    void* operator new(size_t, RenderArena*) throw();

    // Overridden to prevent the normal delete from being called.
    void operator delete(void*, size_t);

private:
    // The normal operator new is disallowed on all render objects.
    void* operator new(size_t) throw();

public:
    RenderArena* renderArena() const { return document()->renderArena(); }

    virtual bool isApplet() const { return false; }
    virtual bool isBR() const { return false; }
    virtual bool isBlockFlow() const { return false; }
    virtual bool isBoxModelObject() const { return false; }
    virtual bool isCounter() const { return false; }
    virtual bool isFieldset() const { return false; }
    virtual bool isFrame() const { return false; }
    virtual bool isFrameSet() const { return false; }
    virtual bool isImage() const { return false; }
    virtual bool isInlineBlockOrInlineTable() const { return false; }
    virtual bool isListBox() const { return false; }
    virtual bool isListItem() const { return false; }
    virtual bool isListMarker() const { return false; }
    virtual bool isMedia() const { return false; }
    virtual bool isMenuList() const { return false; }
    virtual bool isRenderBlock() const { return false; }
    virtual bool isRenderButton() const { return false; }
    virtual bool isRenderImage() const { return false; }
    virtual bool isRenderInline() const { return false; }
    virtual bool isRenderPart() const { return false; }
    virtual bool isRenderView() const { return false; }
    virtual bool isSlider() const { return false; }
    virtual bool isTable() const { return false; }
    virtual bool isTableCell() const { return false; }
    virtual bool isTableCol() const { return false; }
    virtual bool isTableRow() const { return false; }
    virtual bool isTableSection() const { return false; }
    virtual bool isTextControl() const { return false; }
    virtual bool isTextArea() const { return false; }
    virtual bool isTextField() const { return false; }
    virtual bool isWidget() const { return false; }

    bool isRoot() const { return document()->documentElement() == m_node; }
    bool isBody() const;
    bool isHR() const;

    bool isHTMLMarquee() const;

    bool childrenInline() const { return m_childrenInline; }
    void setChildrenInline(bool b = true) { m_childrenInline = b; }
    bool hasColumns() const { return m_hasColumns; }
    void setHasColumns(bool b = true) { m_hasColumns = b; }
    bool cellWidthChanged() const { return m_cellWidthChanged; }
    void setCellWidthChanged(bool b = true) { m_cellWidthChanged = b; }

#if ENABLE(SVG)
    virtual bool isSVGRoot() const { return false; }
    virtual bool isSVGContainer() const { return false; }
    virtual bool isSVGHiddenContainer() const { return false; }
    virtual bool isRenderPath() const { return false; }
    virtual bool isSVGText() const { return false; }

    virtual FloatRect relativeBBox(bool includeStroke = true) const;

    virtual TransformationMatrix localTransform() const;
    virtual TransformationMatrix absoluteTransform() const;
#endif

    bool isAnonymous() const { return m_isAnonymous; }
    void setIsAnonymous(bool b) { m_isAnonymous = b; }
    bool isAnonymousBlock() const
    {
        return m_isAnonymous && style()->display() == BLOCK && style()->styleType() == NOPSEUDO && !isListMarker();
    }
    bool isInlineContinuation() const { return (node() ? node()->renderer() != this : false) && isRenderInline(); }
    bool isFloating() const { return m_floating; }
    bool isPositioned() const { return m_positioned; } // absolute or fixed positioning
    bool isRelPositioned() const { return m_relPositioned; } // relative positioning