renderinline.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

/*
 * 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, 2004, 2005, 2006 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., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "RenderInline.h"

#include "FloatQuad.h"
#include "GraphicsContext.h"
#include "HitTestResult.h"
#include "Page.h"
#include "RenderArena.h"
#include "RenderBlock.h"
#include "RenderView.h"
#include "VisiblePosition.h"

#if ENABLE(DASHBOARD_SUPPORT)
#include "Frame.h"
#endif

using namespace std;

namespace WebCore {

RenderInline::RenderInline(Node* node)
    : RenderBoxModelObject(node)
    , m_continuation(0)
    , m_lineHeight(-1)
    , m_verticalPosition(PositionUndefined)
{
    setChildrenInline(true);
}

RenderInline::~RenderInline()
{
}

void RenderInline::destroy()
{
    // Detach our continuation first.
    if (m_continuation)
        m_continuation->destroy();
    m_continuation = 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 RenderBoxModelObject::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 line boxes are contained inside a root, that means we're an inline.
            // In that case, we need to remove all the line boxes so that the parent
            // lines aren't pointing to deleted children. If the first line box does
            // not have a parent that means they are either already disconnected or
            // root lines that can just be destroyed without disconnecting.
            if (firstLineBox()->parent()) {
                for (InlineRunBox* box = firstLineBox(); box; box = box->nextLineBox())
                    box->remove();
            }
        } else if (isInline() && parent())
            parent()->dirtyLinesFromChangedChild(this);
    }

    m_lineBoxes.deleteLineBoxes(renderArena());

    RenderBoxModelObject::destroy();
}

RenderInline* RenderInline::inlineContinuation() const
{
    if (!m_continuation || m_continuation->isInline())
        return toRenderInline(m_continuation);
    return toRenderBlock(m_continuation)->inlineContinuation();
}

void RenderInline::updateBoxModelInfoFromStyle()
{
    RenderBoxModelObject::updateBoxModelInfoFromStyle();

    setInline(true); // Needed for run-ins, since run-in is considered a block display type.

    // FIXME: Support transforms and reflections on inline flows someday.
    setHasTransform(false);
    setHasReflection(false);    
}

void RenderInline::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBoxModelObject::styleDidChange(diff, oldStyle);

    // Ensure that all of the split inlines pick up the new style. We
    // only do this if we're an inline, since we don't want to propagate
    // a block's style to the other inlines.
    // e.g., <font>foo <h4>goo</h4> moo</font>.  The <font> inlines before
    // and after the block share the same style, but the block doesn't
    // need to pass its style on to anyone else.
    for (RenderInline* currCont = inlineContinuation(); currCont; currCont = currCont->inlineContinuation()) {
        RenderBoxModelObject* nextCont = currCont->continuation();
        currCont->setContinuation(0);
        currCont->setStyle(style());
        currCont->setContinuation(nextCont);
    }

    m_lineHeight = -1;

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

static inline bool isAfterContent(RenderObject* child)
{
    if (!child)
        return false;
    if (child->style()->styleType() != AFTER)
        return false;
    // Text nodes don't have their own styles, so ignore the style on a text node.
    if (child->isText() && !child->isBR())
        return false;
    return true;
}

void RenderInline::addChild(RenderObject* newChild, RenderObject* beforeChild)
{
    if (continuation())
        return addChildToContinuation(newChild, beforeChild);
    return addChildIgnoringContinuation(newChild, beforeChild);
}

static RenderBoxModelObject* nextContinuation(RenderObject* renderer)
{
    if (renderer->isInline() && !renderer->isReplaced())
        return toRenderInline(renderer)->continuation();
    return toRenderBlock(renderer)->inlineContinuation();
}

RenderBoxModelObject* RenderInline::continuationBefore(RenderObject* beforeChild)
{
    if (beforeChild && beforeChild->parent() == this)
        return this;

    RenderBoxModelObject* curr = nextContinuation(this);
    RenderBoxModelObject* nextToLast = this;
    RenderBoxModelObject* last = this;
    while (curr) {
        if (beforeChild && beforeChild->parent() == curr) {
            if (curr->firstChild() == beforeChild)
                return last;
            return curr;
        }

        nextToLast = last;
        last = curr;
        curr = nextContinuation(curr);
    }

    if (!beforeChild && !last->firstChild())
        return nextToLast;
    return last;
}

void RenderInline::addChildIgnoringContinuation(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();

    if (!newChild->isInline() && !newChild->isFloatingOrPositioned()) {
        // We are placing a block inside an inline. We have to perform a split of this
        // inline into continuations.  This involves creating an anonymous block box to hold
        // |newChild|.  We then make that block box a continuation of this inline.  We take all of
        // the children after |beforeChild| and put them in a clone of this object.
        RefPtr<RenderStyle> newStyle = RenderStyle::create();
        newStyle->inheritFrom(style());
        newStyle->setDisplay(BLOCK);

        RenderBlock* newBox = new (renderArena()) RenderBlock(document() /* anonymous box */);
        newBox->setStyle(newStyle.release());
        RenderBoxModelObject* oldContinuation = continuation();
        setContinuation(newBox);

        // Someone may have put a <p> inside a <q>, causing a split.  When this happens, the :after content
        // has to move into the inline continuation.  Call updateBeforeAfterContent to ensure that our :after
        // content gets properly destroyed.
        bool isLastChild = (beforeChild == lastChild());
        if (document()->usesBeforeAfterRules())
            children()->updateBeforeAfterContent(this, AFTER);
        if (isLastChild && beforeChild != lastChild())
            beforeChild = 0; // We destroyed the last child, so now we need to update our insertion
                             // point to be 0.  It's just a straight append now.

        splitFlow(beforeChild, newBox, newChild, oldContinuation);
        return;
    }

    RenderBoxModelObject::addChild(newChild, beforeChild);

    newChild->setNeedsLayoutAndPrefWidthsRecalc();
}

RenderInline* RenderInline::cloneInline(RenderInline* src)
{
    RenderInline* o = new (src->renderArena()) RenderInline(src->node());
    o->setStyle(src->style());
    return o;
}

void RenderInline::splitInlines(RenderBlock* fromBlock, RenderBlock* toBlock,
                                RenderBlock* middleBlock,
                                RenderObject* beforeChild, RenderBoxModelObject* oldCont)
{
    // Create a clone of this inline.
    RenderInline* clone = cloneInline(this);
    clone->setContinuation(oldCont);

    // Now take all of the children from beforeChild to the end and remove
    // them from |this| and place them in the clone.
    RenderObject* o = beforeChild;
    while (o) {
        RenderObject* tmp = o;
        o = tmp->nextSibling();
        clone->addChildIgnoringContinuation(children()->removeChildNode(this, tmp), 0);
        tmp->setNeedsLayoutAndPrefWidthsRecalc();
    }

    // Hook |clone| up as the continuation of the middle block.
    middleBlock->setInlineContinuation(clone);

    // We have been reparented and are now under the fromBlock.  We need
    // to walk up our inline parent chain until we hit the containing block.
    // Once we hit the containing block we're done.
    RenderBoxModelObject* curr = static_cast<RenderBoxModelObject*>(parent());
    RenderBoxModelObject* currChild = this;
    
    // FIXME: Because splitting is O(n^2) as tags nest pathologically, we cap the depth at which we're willing to clone.
    // There will eventually be a better approach to this problem that will let us nest to a much
    // greater depth (see bugzilla bug 13430) but for now we have a limit.  This *will* result in
    // incorrect rendering, but the alternative is to hang forever.
    unsigned splitDepth = 1;
    const unsigned cMaxSplitDepth = 200; 
    while (curr && curr != fromBlock) {
        ASSERT(curr->isRenderInline());
        if (splitDepth < cMaxSplitDepth) {
            // Create a new clone.
            RenderInline* cloneChild = clone;
            clone = cloneInline(toRenderInline(curr));

            // Insert our child clone as the first child.
            clone->addChildIgnoringContinuation(cloneChild, 0);

            // Hook the clone up as a continuation of |curr|.
            RenderInline* inlineCurr = toRenderInline(curr);
            oldCont = inlineCurr->continuation();
            inlineCurr->setContinuation(clone);
            clone->setContinuation(oldCont);

            // Someone may have indirectly caused a <q> to split.  When this happens, the :after content
            // has to move into the inline continuation.  Call updateBeforeAfterContent to ensure that the inline's :after
            // content gets properly destroyed.
            if (document()->usesBeforeAfterRules())
                inlineCurr->children()->updateBeforeAfterContent(this, AFTER);

            // Now we need to take all of the children starting from the first child
            // *after* currChild and append them all to the clone.
            o = currChild->nextSibling();
            while (o) {
                RenderObject* tmp = o;
                o = tmp->nextSibling();
                clone->addChildIgnoringContinuation(inlineCurr->children()->removeChildNode(curr, tmp), 0);
                tmp->setNeedsLayoutAndPrefWidthsRecalc();
            }
        }
        
        // Keep walking up the chain.
        currChild = curr;
        curr = static_cast<RenderBoxModelObject*>(curr->parent());
        splitDepth++;
    }

    // Now we are at the block level. We need to put the clone into the toBlock.
    toBlock->children()->appendChildNode(toBlock, clone);

    // Now take all the children after currChild and remove them from the fromBlock
    // and put them in the toBlock.
    o = currChild->nextSibling();
    while (o) {
        RenderObject* tmp = o;
        o = tmp->nextSibling();
        toBlock->children()->appendChildNode(toBlock, fromBlock->children()->removeChildNode(fromBlock, tmp));
    }
}

void RenderInline::splitFlow(RenderObject* beforeChild, RenderBlock* newBlockBox,
                             RenderObject* newChild, RenderBoxModelObject* oldCont)
{
    RenderBlock* pre = 0;
    RenderBlock* block = containingBlock();
    
    // Delete our line boxes before we do the inline split into continuations.
    block->deleteLineBoxTree();
    
    bool madeNewBeforeBlock = false;
    if (block->isAnonymousBlock() && (!block->parent() || !block->parent()->createsAnonymousWrapper())) {
        // We can reuse this block and make it the preBlock of the next continuation.
        pre = block;
        block = block->containingBlock();
    } else {
        // No anonymous block available for use.  Make one.
        pre = block->createAnonymousBlock();
        madeNewBeforeBlock = true;
    }

    RenderBlock* post = block->createAnonymousBlock();