renderblock.cpp

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) 1999 Lars Knoll ([e-mail])
 *           (C) 1999 Antti Koivisto ([e-mail])
 *           (C) 2007 David Smith ([e-mail])
 * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 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.
 */

#include "config.h"
#include "RenderBlock.h"

#include "Document.h"
#include "Element.h"
#include "FloatQuad.h"
#include "Frame.h"
#include "FrameView.h"
#include "GraphicsContext.h"
#include "HTMLNames.h"
#include "HitTestResult.h"
#include "InlineTextBox.h"
#include "RenderImage.h"
#include "RenderInline.h"
#include "RenderMarquee.h"
#include "RenderReplica.h"
#include "RenderTableCell.h"
#include "RenderTextFragment.h"
#include "RenderTheme.h"
#include "RenderView.h"
#include "SelectionController.h"
#include <wtf/StdLibExtras.h>

using namespace std;
using namespace WTF;
using namespace Unicode;

namespace WebCore {

// Number of pixels to allow as a fudge factor when clicking above or below a line.
// clicking up to verticalLineClickFudgeFactor pixels above a line will correspond to the closest point on the line.   
const int verticalLineClickFudgeFactor= 3;

using namespace HTMLNames;

static void moveChild(RenderObject* to, RenderObjectChildList* toChildList, RenderObject* from, RenderObjectChildList* fromChildList, RenderObject* child)
{
    ASSERT(from == child->parent());
    toChildList->appendChildNode(to, fromChildList->removeChildNode(from, child, false), false);
}

struct ColumnInfo {
    ColumnInfo()
        : m_desiredColumnWidth(0)
        , m_desiredColumnCount(1)
        { }
    int m_desiredColumnWidth;
    unsigned m_desiredColumnCount;
    Vector<IntRect> m_columnRects;
};

typedef WTF::HashMap<const RenderBox*, ColumnInfo*> ColumnInfoMap;
static ColumnInfoMap* gColumnInfoMap = 0;

typedef WTF::HashMap<const RenderBlock*, HashSet<RenderBox*>*> PercentHeightDescendantsMap;
static PercentHeightDescendantsMap* gPercentHeightDescendantsMap = 0;

typedef WTF::HashMap<const RenderBox*, HashSet<RenderBlock*>*> PercentHeightContainerMap;
static PercentHeightContainerMap* gPercentHeightContainerMap = 0;
    
typedef WTF::HashMap<RenderBlock*, ListHashSet<RenderInline*>*> ContinuationOutlineTableMap;

// Our MarginInfo state used when laying out block children.
RenderBlock::MarginInfo::MarginInfo(RenderBlock* block, int top, int bottom)
{
    // Whether or not we can collapse our own margins with our children.  We don't do this
    // if we had any border/padding (obviously), if we're the root or HTML elements, or if
    // we're positioned, floating, a table cell.
    m_canCollapseWithChildren = !block->isRenderView() && !block->isRoot() && !block->isPositioned() &&
        !block->isFloating() && !block->isTableCell() && !block->hasOverflowClip() && !block->isInlineBlockOrInlineTable();

    m_canCollapseTopWithChildren = m_canCollapseWithChildren && (top == 0) && block->style()->marginTopCollapse() != MSEPARATE;

    // If any height other than auto is specified in CSS, then we don't collapse our bottom
    // margins with our children's margins.  To do otherwise would be to risk odd visual
    // effects when the children overflow out of the parent block and yet still collapse
    // with it.  We also don't collapse if we have any bottom border/padding.
    m_canCollapseBottomWithChildren = m_canCollapseWithChildren && (bottom == 0) &&
        (block->style()->height().isAuto() && block->style()->height().value() == 0) && block->style()->marginBottomCollapse() != MSEPARATE;
    
    m_quirkContainer = block->isTableCell() || block->isBody() || block->style()->marginTopCollapse() == MDISCARD || 
        block->style()->marginBottomCollapse() == MDISCARD;

    m_atTopOfBlock = true;
    m_atBottomOfBlock = false;

    m_posMargin = m_canCollapseTopWithChildren ? block->maxTopMargin(true) : 0;
    m_negMargin = m_canCollapseTopWithChildren ? block->maxTopMargin(false) : 0;

    m_selfCollapsingBlockClearedFloat = false;
    
    m_topQuirk = m_bottomQuirk = m_determinedTopQuirk = false;
}

// -------------------------------------------------------------------------------------------------------

RenderBlock::RenderBlock(Node* node)
      : RenderBox(node)
      , m_floatingObjects(0)
      , m_positionedObjects(0)
      , m_inlineContinuation(0)
      , m_maxMargin(0)
      , m_overflowHeight(0)
      , m_overflowWidth(0)
      , m_overflowLeft(0)
      , m_overflowTop(0)
      , m_lineHeight(-1)
{
    setChildrenInline(true);
}

RenderBlock::~RenderBlock()
{
    delete m_floatingObjects;
    delete m_positionedObjects;
    delete m_maxMargin;
    
    if (hasColumns())
        delete gColumnInfoMap->take(this);

    if (gPercentHeightDescendantsMap) {
        if (HashSet<RenderBox*>* descendantSet = gPercentHeightDescendantsMap->take(this)) {
            HashSet<RenderBox*>::iterator end = descendantSet->end();
            for (HashSet<RenderBox*>::iterator descendant = descendantSet->begin(); descendant != end; ++descendant) {
                HashSet<RenderBlock*>* containerSet = gPercentHeightContainerMap->get(*descendant);
                ASSERT(containerSet);
                if (!containerSet)
                    continue;
                ASSERT(containerSet->contains(this));
                containerSet->remove(this);
                if (containerSet->isEmpty()) {
                    gPercentHeightContainerMap->remove(*descendant);
                    delete containerSet;
                }
            }
            delete descendantSet;
        }
    }
}

void RenderBlock::destroy()
{
    // Detach our continuation first.
    if (m_inlineContinuation)
        m_inlineContinuation->destroy();
    m_inlineContinuation = 0;
    
    // Make sure to destroy anonymous children first while they are still connected to the rest of the tree, so that they will
    // properly dirty line boxes that they are removed from.  Effects that do :before/:after only on hover could crash otherwise.
    children()->destroyLeftoverChildren();

    if (!documentBeingDestroyed()) {
        if (firstLineBox()) {
            // We can't wait for RenderBox::destroy to clear the selection,
            // because by then we will have nuked the line boxes.
            // FIXME: The SelectionController should be responsible for this when it
            // is notified of DOM mutations.
            if (isSelectionBorder())
                view()->clearSelection();

            // If we are an anonymous block, then our line boxes might have children
            // that will outlast this block. In the non-anonymous block case those
            // children will be destroyed by the time we return from this function.
            if (isAnonymousBlock()) {
                for (InlineFlowBox* box = firstLineBox(); box; box = box->nextFlowBox()) {
                    while (InlineBox* childBox = box->firstChild())
                        childBox->remove();
                }
            }
        } else if (isInline() && parent())
            parent()->dirtyLinesFromChangedChild(this);
    }

    m_lineBoxes.deleteLineBoxes(renderArena());

    RenderBox::destroy();
}

void RenderBlock::styleWillChange(StyleDifference diff, const RenderStyle* newStyle)
{
    setReplaced(newStyle->isDisplayReplacedType());
    
    if (style() && parent() && diff == StyleDifferenceLayout && style()->position() != newStyle->position()) {
        if (newStyle->position() == StaticPosition)
            // Clear our positioned objects list. Our absolutely positioned descendants will be
            // inserted into our containing block's positioned objects list during layout.
            removePositionedObjects(0);
        else if (style()->position() == StaticPosition) {
            // Remove our absolutely positioned descendants from their current containing block.
            // They will be inserted into our positioned objects list during layout.
            RenderObject* cb = parent();
            while (cb && (cb->style()->position() == StaticPosition || (cb->isInline() && !cb->isReplaced())) && !cb->isRenderView()) {
                if (cb->style()->position() == RelativePosition && cb->isInline() && !cb->isReplaced()) {
                    cb = cb->containingBlock();
                    break;
                }
                cb = cb->parent();
            }
            
            if (cb->isRenderBlock())
                toRenderBlock(cb)->removePositionedObjects(this);
        }
    }

    RenderBox::styleWillChange(diff, newStyle);
}

void RenderBlock::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBox::styleDidChange(diff, oldStyle);

    // FIXME: We could save this call when the change only affected non-inherited properties
    for (RenderObject* child = firstChild(); child; child = child->nextSibling()) {
        if (child->isAnonymousBlock()) {
            RefPtr<RenderStyle> newStyle = RenderStyle::create();
            newStyle->inheritFrom(style());
            newStyle->setDisplay(BLOCK);
            child->setStyle(newStyle.release());
        }
    }

    m_lineHeight = -1;

    // Update pseudos for :before and :after now.
    if (!isAnonymous() && document()->usesBeforeAfterRules() && canHaveChildren()) {
        updateBeforeAfterContent(BEFORE);
        updateBeforeAfterContent(AFTER);
    }
    updateFirstLetter();
}

void RenderBlock::updateBeforeAfterContent(PseudoId pseudoId)
{
    // If this is an anonymous wrapper, then the parent applies its own pseudo-element style to it.
    if (parent() && parent()->createsAnonymousWrapper())
        return;
    return children()->updateBeforeAfterContent(this, pseudoId);
}
    
void RenderBlock::addChild(RenderObject* newChild, RenderObject* beforeChild)
{
    // Make sure we don't append things after :after-generated content if we have it.
    if (!beforeChild && isAfterContent(lastChild()))
        beforeChild = lastChild();

    bool madeBoxesNonInline = false;

    // If the requested beforeChild is not one of our children, then this is because
    // there is an anonymous container within this object that contains the beforeChild.
    if (beforeChild && beforeChild->parent() != this) {
        RenderObject* anonymousChild = beforeChild->parent();
        ASSERT(anonymousChild);

        while (anonymousChild->parent() != this)
            anonymousChild = anonymousChild->parent();

        ASSERT(anonymousChild->isAnonymous());

        if (anonymousChild->isAnonymousBlock()) {
            // Insert the child into the anonymous block box instead of here.
            if (newChild->isInline() || beforeChild->parent()->firstChild() != beforeChild)
                beforeChild->parent()->addChild(newChild, beforeChild);
            else
                addChild(newChild, beforeChild->parent());
            return;
        }

        ASSERT(anonymousChild->isTable());
        if (newChild->isTableCol() && newChild->style()->display() == TABLE_COLUMN_GROUP
                || newChild->isRenderBlock() && newChild->style()->display() == TABLE_CAPTION
                || newChild->isTableSection()
                || newChild->isTableRow()
                || newChild->isTableCell()) {
            // Insert into the anonymous table.
            anonymousChild->addChild(newChild, beforeChild);
            return;
        }

        // Go on to insert before the anonymous table.
        beforeChild = anonymousChild;
    }

    // A block has to either have all of its children inline, or all of its children as blocks.
    // So, if our children are currently inline and a block child has to be inserted, we move all our
    // inline children into anonymous block boxes.