render_block.cpp

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/*
 * This file is part of the render object implementation for KHTML.
 *
 * Copyright (C) 1999 Lars Knoll ([e-mail])
 *           (C) 1999 Antti Koivisto ([e-mail])
 * Copyright (C) 2003 Apple Computer, Inc.
 *
 * 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., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 */

//#define DEBUG
//#define DEBUG_LAYOUT
//#define BOX_DEBUG
//#define FLOAT_DEBUG
#include <kdebug.h>
#include "rendering/render_text.h"
#include "rendering/render_table.h"
#include "rendering/render_canvas.h"
#include "xml/dom_nodeimpl.h"
#include "xml/dom_docimpl.h"
#include "xml/dom_position.h"
#include "html/html_formimpl.h"
#include "render_block.h"
#include "editing/selection.h"

#include "khtmlview.h"
#include "khtml_part.h"
#include "htmltags.h"

using namespace DOM;

namespace khtml {

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

// 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->isCanvas() && !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().isVariable() && 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(DOM::NodeImpl* node)
:RenderFlow(node)
{
    m_childrenInline = true;
    m_floatingObjects = 0;
    m_positionedObjects = 0;
    m_pre = false;
    m_firstLine = false;
    m_hasMarkupTruncation = false;
    m_selectionState = SelectionNone;
    m_clearStatus = CNONE;
    m_maxTopPosMargin = m_maxTopNegMargin = m_maxBottomPosMargin = m_maxBottomNegMargin = 0;
    m_topMarginQuirk = m_bottomMarginQuirk = false;
    m_overflowHeight = m_overflowWidth = 0;
    m_overflowLeft = m_overflowTop = 0;
}

RenderBlock::~RenderBlock()
{
    delete m_floatingObjects;
    delete m_positionedObjects;
}

void RenderBlock::setStyle(RenderStyle* _style)
{
    setReplaced(_style->isDisplayReplacedType());

    RenderFlow::setStyle(_style);

    m_pre = false;
    if (_style->whiteSpace() == PRE)
        m_pre = true;

    // ### we could save this call when the change only affected
    // non inherited properties
    RenderObject *child = firstChild();
    while (child != 0)
    {
        if (child->isAnonymousBlock())
        {
            RenderStyle* newStyle = new (renderArena()) RenderStyle();
            newStyle->inheritFrom(style());
            newStyle->setDisplay(BLOCK);
            child->setStyle(newStyle);
        }
        child = child->nextSibling();
    }

    m_lineHeight = -1;

    // Update pseudos for :before and :after now.
    updatePseudoChild(RenderStyle::BEFORE, firstChild());
    updatePseudoChild(RenderStyle::AFTER, lastChild());
}

void RenderBlock::addChildToFlow(RenderObject* newChild, RenderObject* beforeChild)
{
    // Make sure we don't append things after :after-generated content if we have it.
    if (!beforeChild && lastChild() && lastChild()->style()->styleType() == RenderStyle::AFTER)
        beforeChild = lastChild();

    bool madeBoxesNonInline = FALSE;

    // If the requested beforeChild is not one of our children, then this is most likely because
    // there is an anonymous block box within this object that contains the beforeChild. So
    // just insert the child into the anonymous block box instead of here.
    if (beforeChild && beforeChild->parent() != this) {

        KHTMLAssert(beforeChild->parent());
        KHTMLAssert(beforeChild->parent()->isAnonymousBlock());

        if (newChild->isInline()) {
            beforeChild->parent()->addChild(newChild,beforeChild);
            return;
        }
        else if (beforeChild->parent()->firstChild() != beforeChild)
            return beforeChild->parent()->addChild(newChild, beforeChild);
        else
            return addChildToFlow(newChild, beforeChild->parent());
    }

    // 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
    if ( m_childrenInline && !newChild->isInline() && !newChild->isFloatingOrPositioned() )
    {
        // This is a block with inline content. Wrap the inline content in anonymous blocks.
        makeChildrenNonInline(beforeChild);
        madeBoxesNonInline = true;

        if (beforeChild && beforeChild->parent() != this) {
            beforeChild = beforeChild->parent();
            KHTMLAssert(beforeChild->isAnonymousBlock());
            KHTMLAssert(beforeChild->parent() == this);
        }
    }
    else if (!m_childrenInline && !newChild->isFloatingOrPositioned())
    {
        // If we're inserting an inline child but all of our children are blocks, then we have to make sure
        // it is put into an anomyous block box. We try to use an existing anonymous box if possible, otherwise
        // a new one is created and inserted into our list of children in the appropriate position.
        if (newChild->isInline()) {
            if (beforeChild) {
                if (beforeChild->previousSibling() && beforeChild->previousSibling()->isAnonymousBlock()) {
                    beforeChild->previousSibling()->addChild(newChild);
                    return;
                }
            }
            else {
                if (m_last && m_last->isAnonymousBlock()) {
                    m_last->addChild(newChild);
                    return;
                }
            }

            // no suitable existing anonymous box - create a new one
            RenderBlock* newBox = createAnonymousBlock();
            RenderContainer::addChild(newBox,beforeChild);
            newBox->addChild(newChild);
            return;
        }
    }

    RenderContainer::addChild(newChild,beforeChild);
    // ### care about aligned stuff

    if ( madeBoxesNonInline )
        removeLeftoverAnonymousBoxes();
}

static void getInlineRun(RenderObject* start, RenderObject* boundary,
                         RenderObject*& inlineRunStart,
                         RenderObject*& inlineRunEnd)
{
    // Beginning at |start| we find the largest contiguous run of inlines that
    // we can.  We denote the run with start and end points, |inlineRunStart|
    // and |inlineRunEnd|.  Note that these two values may be the same if
    // we encounter only one inline.
    //
    // We skip any non-inlines we encounter as long as we haven't found any
    // inlines yet.
    //
    // |boundary| indicates a non-inclusive boundary point.  Regardless of whether |boundary|
    // is inline or not, we will not include it in a run with inlines before it.  It's as though we encountered
    // a non-inline.

    // Start by skipping as many non-inlines as we can.
    RenderObject * curr = start;
    bool sawInline;
    do {
        while (curr && !(curr->isInline() || curr->isFloatingOrPositioned()))
            curr = curr->nextSibling();

        inlineRunStart = inlineRunEnd = curr;

        if (!curr)
            return; // No more inline children to be found.

        sawInline = curr->isInline();

        curr = curr->nextSibling();
        while (curr && (curr->isInline() || curr->isFloatingOrPositioned()) && (curr != boundary)) {
            inlineRunEnd = curr;
            if (curr->isInline())
                sawInline = true;
            curr = curr->nextSibling();
        }
    } while (!sawInline);
}

void RenderBlock::makeChildrenNonInline(RenderObject *insertionPoint)
{
    // makeChildrenNonInline takes a block whose children are *all* inline and it
    // makes sure that inline children are coalesced under anonymous
    // blocks.  If |insertionPoint| is defined, then it represents the insertion point for
    // the new block child that is causing us to have to wrap all the inlines.  This
    // means that we cannot coalesce inlines before |insertionPoint| with inlines following
    // |insertionPoint|, because the new child is going to be inserted in between the inlines,
    // splitting them.
    KHTMLAssert(isInlineBlockOrInlineTable() || !isInline());
    KHTMLAssert(!insertionPoint || insertionPoint->parent() == this);

    m_childrenInline = false;

    RenderObject *child = firstChild();

    while (child) {
        RenderObject *inlineRunStart, *inlineRunEnd;
        getInlineRun(child, insertionPoint, inlineRunStart, inlineRunEnd);

        if (!inlineRunStart)
            break;

        child = inlineRunEnd->nextSibling();

        RenderBlock* box = createAnonymousBlock();
        insertChildNode(box, inlineRunStart);
        RenderObject* o = inlineRunStart;
        while(o != inlineRunEnd)
        {
            RenderObject* no = o;
            o = no->nextSibling();
            box->appendChildNode(removeChildNode(no));
        }
        box->appendChildNode(removeChildNode(inlineRunEnd));
    }

#ifndef NDEBUG
    for (RenderObject *c = firstChild(); c; c = c->nextSibling())
        KHTMLAssert(!c->isInline());
#endif
}

void RenderBlock::removeChild(RenderObject *oldChild)
{
    // If this child is a block, and if our previous and next siblings are
    // both anonymous blocks with inline content, then we can go ahead and
    // fold the inline content back together.
    RenderObject* prev = oldChild->previousSibling();
    RenderObject* next = oldChild->nextSibling();
    bool canDeleteAnonymousBlocks = !documentBeingDestroyed() && !isInline() && !oldChild->isInline() &&
                                    !oldChild->continuation() &&
                                    (!prev || (prev->isAnonymousBlock() && prev->childrenInline())) &&