/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
 * Copyright (C) 2010 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.
 *
 */

#include "config.h"

#include "BidiResolver.h"
#include "Hyphenation.h"
#include "InlineIterator.h"
#include "InlineTextBox.h"
#include "Logging.h"
#include "RenderArena.h"
#include "RenderCombineText.h"
#include "RenderInline.h"
#include "RenderLayer.h"
#include "RenderListMarker.h"
#include "RenderRubyRun.h"
#include "RenderView.h"
#include "Settings.h"
#include "TextBreakIterator.h"
#include "TextRun.h"
#include "TrailingFloatsRootInlineBox.h"
#include "VerticalPositionCache.h"
#include "break_lines.h"
#include <wtf/AlwaysInline.h>
#include <wtf/RefCountedLeakCounter.h>
#include <wtf/StdLibExtras.h>
#include <wtf/Vector.h>
#include <wtf/unicode/CharacterNames.h>

#if ENABLE(SVG)
#include "RenderSVGInlineText.h"
#include "SVGRootInlineBox.h"
#endif

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

namespace WebCore {

// We don't let our line box tree for a single line get any deeper than this.
const unsigned cMaxLineDepth = 200;

class LineInfo {
public:
    LineInfo()
        : m_isFirstLine(true)
        , m_isLastLine(false)
        , m_isEmpty(true)
        , m_previousLineBrokeCleanly(true)
    { }

    bool isFirstLine() const { return m_isFirstLine; }
    bool isLastLine() const { return m_isLastLine; }
    bool isEmpty() const { return m_isEmpty; }
    bool previousLineBrokeCleanly() const { return m_previousLineBrokeCleanly; }

    void setFirstLine(bool firstLine) { m_isFirstLine = firstLine; }
    void setLastLine(bool lastLine) { m_isLastLine = lastLine; }
    void setEmpty(bool empty) { m_isEmpty = empty; }
    void setPreviousLineBrokeCleanly(bool previousLineBrokeCleanly) { m_previousLineBrokeCleanly = previousLineBrokeCleanly; }

private:
    bool m_isFirstLine;
    bool m_isLastLine;
    bool m_isEmpty;
    bool m_previousLineBrokeCleanly;
};

static inline int borderPaddingMarginStart(RenderInline* child)
{
    return child->marginStart() + child->paddingStart() + child->borderStart();
}

static inline int borderPaddingMarginEnd(RenderInline* child)
{
    return child->marginEnd() + child->paddingEnd() + child->borderEnd();
}

static int inlineLogicalWidth(RenderObject* child, bool start = true, bool end = true)
{
    unsigned lineDepth = 1;
    int extraWidth = 0;
    RenderObject* parent = child->parent();
    while (parent->isRenderInline() && lineDepth++ < cMaxLineDepth) {
        RenderInline* parentAsRenderInline = toRenderInline(parent);
        if (start && !child->previousSibling())
            extraWidth += borderPaddingMarginStart(parentAsRenderInline);
        if (end && !child->nextSibling())
            extraWidth += borderPaddingMarginEnd(parentAsRenderInline);
        child = parent;
        parent = child->parent();
    }
    return extraWidth;
}

static void checkMidpoints(LineMidpointState& lineMidpointState, InlineIterator& lBreak)
{
    // Check to see if our last midpoint is a start point beyond the line break.  If so,
    // shave it off the list, and shave off a trailing space if the previous end point doesn't
    // preserve whitespace.
    if (lBreak.m_obj && lineMidpointState.numMidpoints && !(lineMidpointState.numMidpoints % 2)) {
        InlineIterator* midpoints = lineMidpointState.midpoints.data();
        InlineIterator& endpoint = midpoints[lineMidpointState.numMidpoints - 2];
        const InlineIterator& startpoint = midpoints[lineMidpointState.numMidpoints - 1];
        InlineIterator currpoint = endpoint;
        while (!currpoint.atEnd() && currpoint != startpoint && currpoint != lBreak)
            currpoint.increment();
        if (currpoint == lBreak) {
            // We hit the line break before the start point.  Shave off the start point.
            lineMidpointState.numMidpoints--;
            if (endpoint.m_obj->style()->collapseWhiteSpace())
                endpoint.m_pos--;
        }
    }
}

static void addMidpoint(LineMidpointState& lineMidpointState, const InlineIterator& midpoint)
{
    if (lineMidpointState.midpoints.size() <= lineMidpointState.numMidpoints)
        lineMidpointState.midpoints.grow(lineMidpointState.numMidpoints + 10);

    InlineIterator* midpoints = lineMidpointState.midpoints.data();
    midpoints[lineMidpointState.numMidpoints++] = midpoint;
}

static inline BidiRun* createRun(int start, int end, RenderObject* obj, InlineBidiResolver& resolver)
{
    return new (obj->renderArena()) BidiRun(start, end, obj, resolver.context(), resolver.dir());
}

void RenderBlock::appendRunsForObject(BidiRunList<BidiRun>& runs, int start, int end, RenderObject* obj, InlineBidiResolver& resolver)
{
    if (start > end || obj->isFloating() ||
        (obj->isPositioned() && !obj->style()->isOriginalDisplayInlineType() && !obj->container()->isRenderInline()))
        return;

    LineMidpointState& lineMidpointState = resolver.midpointState();
    bool haveNextMidpoint = (lineMidpointState.currentMidpoint < lineMidpointState.numMidpoints);
    InlineIterator nextMidpoint;
    if (haveNextMidpoint)
        nextMidpoint = lineMidpointState.midpoints[lineMidpointState.currentMidpoint];
    if (lineMidpointState.betweenMidpoints) {
        if (!(haveNextMidpoint && nextMidpoint.m_obj == obj))
            return;
        // This is a new start point. Stop ignoring objects and
        // adjust our start.
        lineMidpointState.betweenMidpoints = false;
        start = nextMidpoint.m_pos;
        lineMidpointState.currentMidpoint++;
        if (start < end)
            return appendRunsForObject(runs, start, end, obj, resolver);
    } else {
        if (!haveNextMidpoint || (obj != nextMidpoint.m_obj)) {
            runs.addRun(createRun(start, end, obj, resolver));
            return;
        }

        // An end midpoint has been encountered within our object.  We
        // need to go ahead and append a run with our endpoint.
        if (static_cast<int>(nextMidpoint.m_pos + 1) <= end) {
            lineMidpointState.betweenMidpoints = true;
            lineMidpointState.currentMidpoint++;
            if (nextMidpoint.m_pos != UINT_MAX) { // UINT_MAX means stop at the object and don't include any of it.
                if (static_cast<int>(nextMidpoint.m_pos + 1) > start)
                    runs.addRun(createRun(start, nextMidpoint.m_pos + 1, obj, resolver));
                return appendRunsForObject(runs, nextMidpoint.m_pos + 1, end, obj, resolver);
            }
        } else
           runs.addRun(createRun(start, end, obj, resolver));
    }
}

static inline InlineBox* createInlineBoxForRenderer(RenderObject* obj, bool isRootLineBox, bool isOnlyRun = false)
{
    if (isRootLineBox)
        return toRenderBlock(obj)->createAndAppendRootInlineBox();

    if (obj->isText()) {
        InlineTextBox* textBox = toRenderText(obj)->createInlineTextBox();
        // We only treat a box as text for a <br> if we are on a line by ourself or in strict mode
        // (Note the use of strict mode.  In "almost strict" mode, we don't treat the box for <br> as text.)
        if (obj->isBR())
            textBox->setIsText(isOnlyRun || obj->document()->inNoQuirksMode());
        return textBox;
    }

    if (obj->isBox())
        return toRenderBox(obj)->createInlineBox();

    return toRenderInline(obj)->createAndAppendInlineFlowBox();
}

static inline void dirtyLineBoxesForRenderer(RenderObject* o, bool fullLayout)
{
    if (o->isText()) {
        if (o->preferredLogicalWidthsDirty() && (o->isCounter() || o->isQuote()))
            toRenderText(o)->computePreferredLogicalWidths(0); // FIXME: Counters depend on this hack. No clue why. Should be investigated and removed.
        toRenderText(o)->dirtyLineBoxes(fullLayout);
    } else
        toRenderInline(o)->dirtyLineBoxes(fullLayout);
}

static bool parentIsConstructedOrHaveNext(InlineFlowBox* parentBox)
{
    do {
        if (parentBox->isConstructed() || parentBox->nextOnLine())
            return true;
        parentBox = parentBox->parent();
    } while (parentBox);
    return false;
}

InlineFlowBox* RenderBlock::createLineBoxes(RenderObject* obj, const LineInfo& lineInfo, InlineBox* childBox)
{
    // See if we have an unconstructed line box for this object that is also
    // the last item on the line.
    unsigned lineDepth = 1;
    InlineFlowBox* parentBox = 0;
    InlineFlowBox* result = 0;
    bool hasDefaultLineBoxContain = style()->lineBoxContain() == RenderStyle::initialLineBoxContain();
    do {
        ASSERT(obj->isRenderInline() || obj == this);

        RenderInline* inlineFlow = (obj != this) ? toRenderInline(obj) : 0;

        // Get the last box we made for this render object.
        parentBox = inlineFlow ? inlineFlow->lastLineBox() : toRenderBlock(obj)->lastLineBox();

        // If this box or its ancestor is constructed then it is from a previous line, and we need
        // to make a new box for our line.  If this box or its ancestor is unconstructed but it has
        // something following it on the line, then we know we have to make a new box
        // as well.  In this situation our inline has actually been split in two on
        // the same line (this can happen with very fancy language mixtures).
        bool constructedNewBox = false;
        bool allowedToConstructNewBox = !hasDefaultLineBoxContain || !inlineFlow || inlineFlow->alwaysCreateLineBoxes();
        bool canUseExistingParentBox = parentBox && !parentIsConstructedOrHaveNext(parentBox);
        if (allowedToConstructNewBox && !canUseExistingParentBox) {
            // We need to make a new box for this render object.  Once
            // made, we need to place it at the end of the current line.
            InlineBox* newBox = createInlineBoxForRenderer(obj, obj == this);
            ASSERT(newBox->isInlineFlowBox());
            parentBox = static_cast<InlineFlowBox*>(newBox);
            parentBox->setFirstLineStyleBit(lineInfo.isFirstLine());
            parentBox->setIsHorizontal(isHorizontalWritingMode());
            if (!hasDefaultLineBoxContain)
                parentBox->clearDescendantsHaveSameLineHeightAndBaseline();
            constructedNewBox = true;
        }

        if (constructedNewBox || canUseExistingParentBox) {
            if (!result)
                result = parentBox;

            // If we have hit the block itself, then |box| represents the root
            // inline box for the line, and it doesn't have to be appended to any parent
            // inline.
            if (childBox)
                parentBox->addToLine(childBox);

            if (!constructedNewBox || obj == this)
                break;

            childBox = parentBox;
        }

        // If we've exceeded our line depth, then jump straight to the root and skip all the remaining
        // intermediate inline flows.
        obj = (++lineDepth >= cMaxLineDepth) ? this : obj->parent();

    } while (true);

    return result;
}

static bool reachedEndOfTextRenderer(const BidiRunList<BidiRun>& bidiRuns)
{
    BidiRun* run = bidiRuns.logicallyLastRun();
    if (!run)
        return true;
    unsigned int pos = run->stop();
    RenderObject* r = run->m_object;
    if (!r->isText() || r->isBR())
        return false;
    RenderText* renderText = toRenderText(r);
    if (pos >= renderText->textLength())
        return true;

    while (isASCIISpace(renderText->characters()[pos])) {
        pos++;
        if (pos >= renderText->textLength())
            return true;
    }
    return false;
}

RootInlineBox* RenderBlock::constructLine(BidiRunList<BidiRun>& bidiRuns, const LineInfo& lineInfo)
{
    ASSERT(bidiRuns.firstRun());

    bool rootHasSelectedChildren = false;
    InlineFlowBox* parentBox = 0;
    for (BidiRun* r = bidiRuns.firstRun(); r; r = r->next()) {
        // Create a box for our object.
        bool isOnlyRun = (bidiRuns.runCount() == 1);
        if (bidiRuns.runCount() == 2 && !r->m_object->isListMarker())
            isOnlyRun = (!style()->isLeftToRightDirection() ? bidiRuns.lastRun() : bidiRuns.firstRun())->m_object->isListMarker();

        InlineBox* box = createInlineBoxForRenderer(r->m_object, false, isOnlyRun);
        r->m_box = box;

        ASSERT(box);
        if (!box)
            continue;

        if (!rootHasSelectedChildren && box->renderer()->selectionState() != RenderObject::SelectionNone)
            rootHasSelectedChildren = true;

        // If we have no parent box yet, or if the run is not simply a sibling,
        // then we need to construct inline boxes as necessary to properly enclose the
        // run's inline box.
        if (!parentBox || parentBox->renderer() != r->m_object->parent())
            // Create new inline boxes all the way back to the appropriate insertion point.
            parentBox = createLineBoxes(r->m_object->parent(), lineInfo, box);
        else {
            // Append the inline box to this line.
            parentBox->addToLine(box);
        }

        bool visuallyOrdered = r->m_object->style()->visuallyOrdered();
        box->setBidiLevel(r->level());

        if (box->isInlineTextBox()) {
            InlineTextBox* text = static_cast<InlineTextBox*>(box);
            text->setStart(r->m_start);
            text->setLen(r->m_stop - r->m_start);
            text->m_dirOverride = r->dirOverride(visuallyOrdered);
            if (r->m_hasHyphen)
                text->setHasHyphen(true);
        }
    }

    // We should have a root inline box.  It should be unconstructed and
    // be the last continuation of our line list.
    ASSERT(lastLineBox() && !lastLineBox()->isConstructed());

    // Set the m_selectedChildren flag on the root inline box if one of the leaf inline box
    // from the bidi runs walk above has a selection state.
    if (rootHasSelectedChildren)
        lastLineBox()->root()->setHasSelectedChildren(true);

    // Set bits on our inline flow boxes that indicate which sides should
    // paint borders/margins/padding.  This knowledge will ultimately be used when
    // we determine the horizontal positions and widths of all the inline boxes on
    // the line.
    bool isLogicallyLastRunWrapped = bidiRuns.logicallyLastRun()->m_object && bidiRuns.logicallyLastRun()->m_object->isText() ? !reachedEndOfTextRenderer(bidiRuns) : true;
    lastLineBox()->determineSpacingForFlowBoxes(lineInfo.isLastLine(), isLogicallyLastRunWrapped, bidiRuns.logicallyLastRun()->m_object);

    // Now mark the line boxes as being constructed.
    lastLineBox()->setConstructed();

    // Return the last line.
    return lastRootBox();
}

ETextAlign RenderBlock::textAlignmentForLine(bool endsWithSoftBreak) const
{
    ETextAlign alignment = style()->textAlign();
    if (!endsWithSoftBreak && alignment == JUSTIFY)
        alignment = TAAUTO;

    return alignment;
}

static void updateLogicalWidthForLeftAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
    // The direction of the block should determine what happens with wide lines.
    // In particular with RTL blocks, wide lines should still spill out to the left.
    if (isLeftToRightDirection) {
        if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun)
            trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
        return;
    }

    if (trailingSpaceRun)
        trailingSpaceRun->m_box->setLogicalWidth(0);
    else if (totalLogicalWidth > availableLogicalWidth)
        logicalLeft -= (totalLogicalWidth - availableLogicalWidth);
}

static void updateLogicalWidthForRightAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
    // Wide lines spill out of the block based off direction.
    // So even if text-align is right, if direction is LTR, wide lines should overflow out of the right
    // side of the block.
    if (isLeftToRightDirection) {
        if (trailingSpaceRun) {
            totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
            trailingSpaceRun->m_box->setLogicalWidth(0);
        }
        if (totalLogicalWidth < availableLogicalWidth)
            logicalLeft += availableLogicalWidth - totalLogicalWidth;
        return;
    }

    if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun) {
        trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
        totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
    } else
        logicalLeft += availableLogicalWidth - totalLogicalWidth;
}

static void updateLogicalWidthForCenterAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
    float trailingSpaceWidth = 0;
    if (trailingSpaceRun) {
        totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
        trailingSpaceWidth = min(trailingSpaceRun->m_box->logicalWidth(), (availableLogicalWidth - totalLogicalWidth + 1) / 2);
        trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceWidth));
    }
    if (isLeftToRightDirection)
        logicalLeft += max<float>((availableLogicalWidth - totalLogicalWidth) / 2, 0);
    else
        logicalLeft += totalLogicalWidth > availableLogicalWidth ? (availableLogicalWidth - totalLogicalWidth) : (availableLogicalWidth - totalLogicalWidth) / 2 - trailingSpaceWidth;
}

void RenderBlock::setMarginsForRubyRun(BidiRun* run, RenderRubyRun* renderer, RenderObject* previousObject, const LineInfo& lineInfo)
{
    int startOverhang;
    int endOverhang;
    RenderObject* nextObject = 0;
    for (BidiRun* runWithNextObject = run->next(); runWithNextObject; runWithNextObject = runWithNextObject->next()) {
        if (!runWithNextObject->m_object->isPositioned() && !runWithNextObject->m_box->isLineBreak()) {
            nextObject = runWithNextObject->m_object;
            break;
        }
    }
    renderer->getOverhang(lineInfo.isFirstLine(), renderer->style()->isLeftToRightDirection() ? previousObject : nextObject, renderer->style()->isLeftToRightDirection() ? nextObject : previousObject, startOverhang, endOverhang);
    setMarginStartForChild(renderer, -startOverhang);
    setMarginEndForChild(renderer, -endOverhang);
}

static inline void setLogicalWidthForTextRun(RootInlineBox* lineBox, BidiRun* run, RenderText* renderer, float xPos, const LineInfo& lineInfo,
                                   GlyphOverflowAndFallbackFontsMap& textBoxDataMap, VerticalPositionCache& verticalPositionCache)
{
    HashSet<const SimpleFontData*> fallbackFonts;
    GlyphOverflow glyphOverflow;
    
    // Always compute glyph overflow if the block's line-box-contain value is "glyphs".
    if (lineBox->fitsToGlyphs()) {
        // If we don't stick out of the root line's font box, then don't bother computing our glyph overflow. This optimization
        // will keep us from computing glyph bounds in nearly all cases.
        bool includeRootLine = lineBox->includesRootLineBoxFontOrLeading();
        int baselineShift = lineBox->verticalPositionForBox(run->m_box, verticalPositionCache);
        int rootDescent = includeRootLine ? lineBox->renderer()->style(lineInfo.isFirstLine())->font().fontMetrics().descent() : 0;
        int rootAscent = includeRootLine ? lineBox->renderer()->style(lineInfo.isFirstLine())->font().fontMetrics().ascent() : 0;
        int boxAscent = renderer->style(lineInfo.isFirstLine())->font().fontMetrics().ascent() - baselineShift;
        int boxDescent = renderer->style(lineInfo.isFirstLine())->font().fontMetrics().descent() + baselineShift;
        if (boxAscent > rootDescent ||  boxDescent > rootAscent)
            glyphOverflow.computeBounds = true; 
    }
    
    int hyphenWidth = 0;
    if (static_cast<InlineTextBox*>(run->m_box)->hasHyphen()) {
        const AtomicString& hyphenString = renderer->style()->hyphenString();
        hyphenWidth = renderer->style(lineInfo.isFirstLine())->font().width(TextRun(hyphenString.characters(), hyphenString.length()));
    }
    run->m_box->setLogicalWidth(renderer->width(run->m_start, run->m_stop - run->m_start, xPos, lineInfo.isFirstLine(), &fallbackFonts, &glyphOverflow) + hyphenWidth);
    if (!fallbackFonts.isEmpty()) {
        ASSERT(run->m_box->isText());
        GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(static_cast<InlineTextBox*>(run->m_box), make_pair(Vector<const SimpleFontData*>(), GlyphOverflow())).first;
        ASSERT(it->second.first.isEmpty());
        copyToVector(fallbackFonts, it->second.first);
        run->m_box->parent()->clearDescendantsHaveSameLineHeightAndBaseline();
    }
    if ((glyphOverflow.top || glyphOverflow.bottom || glyphOverflow.left || glyphOverflow.right)) {
        ASSERT(run->m_box->isText());
        GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(static_cast<InlineTextBox*>(run->m_box), make_pair(Vector<const SimpleFontData*>(), GlyphOverflow())).first;
        it->second.second = glyphOverflow;
        run->m_box->clearKnownToHaveNoOverflow();
    }
}

static inline void computeExpansionForJustifiedText(BidiRun* firstRun, BidiRun* trailingSpaceRun, Vector<unsigned, 16>& expansionOpportunities, unsigned expansionOpportunityCount, float& totalLogicalWidth, float availableLogicalWidth)
{
    if (!expansionOpportunityCount || availableLogicalWidth <= totalLogicalWidth)
        return;

    size_t i = 0;
    for (BidiRun* r = firstRun; r; r = r->next()) {
        if (!r->m_box || r == trailingSpaceRun)
            continue;
        
        if (r->m_object->isText()) {
            unsigned opportunitiesInRun = expansionOpportunities[i++];
            
            ASSERT(opportunitiesInRun <= expansionOpportunityCount);
            
            // Only justify text if whitespace is collapsed.
            if (r->m_object->style()->collapseWhiteSpace()) {
                InlineTextBox* textBox = static_cast<InlineTextBox*>(r->m_box);
                int expansion = (availableLogicalWidth - totalLogicalWidth) * opportunitiesInRun / expansionOpportunityCount;
                textBox->setExpansion(expansion);
                totalLogicalWidth += expansion;
            }
            expansionOpportunityCount -= opportunitiesInRun;
            if (!expansionOpportunityCount)
                break;
        }
    }
}

void RenderBlock::computeInlineDirectionPositionsForLine(RootInlineBox* lineBox, const LineInfo& lineInfo, BidiRun* firstRun, BidiRun* trailingSpaceRun, bool reachedEnd,
                                                         GlyphOverflowAndFallbackFontsMap& textBoxDataMap, VerticalPositionCache& verticalPositionCache)
{
    ETextAlign textAlign = textAlignmentForLine(!reachedEnd && !lineBox->endsWithBreak());
    float logicalLeft = logicalLeftOffsetForLine(logicalHeight(), lineInfo.isFirstLine());
    float availableLogicalWidth = logicalRightOffsetForLine(logicalHeight(), lineInfo.isFirstLine()) - logicalLeft;

    bool needsWordSpacing = false;
    float totalLogicalWidth = lineBox->getFlowSpacingLogicalWidth();
    unsigned expansionOpportunityCount = 0;
    bool isAfterExpansion = true;
    Vector<unsigned, 16> expansionOpportunities;
    RenderObject* previousObject = 0;

    for (BidiRun* r = firstRun; r; r = r->next()) {
        if (!r->m_box || r->m_object->isPositioned() || r->m_box->isLineBreak())
            continue; // Positioned objects are only participating to figure out their
                      // correct static x position.  They have no effect on the width.
                      // Similarly, line break boxes have no effect on the width.
        if (r->m_object->isText()) {
            RenderText* rt = toRenderText(r->m_object);
            if (textAlign == JUSTIFY && r != trailingSpaceRun) {
                if (!isAfterExpansion)
                    static_cast<InlineTextBox*>(r->m_box)->setCanHaveLeadingExpansion(true);
                unsigned opportunitiesInRun = Font::expansionOpportunityCount(rt->characters() + r->m_start, r->m_stop - r->m_start, r->m_box->direction(), isAfterExpansion);
                expansionOpportunities.append(opportunitiesInRun);
                expansionOpportunityCount += opportunitiesInRun;
            }

            if (int length = rt->textLength()) {
                if (!r->m_start && needsWordSpacing && isSpaceOrNewline(rt->characters()[r->m_start]))
                    totalLogicalWidth += rt->style(lineInfo.isFirstLine())->font().wordSpacing();
                needsWordSpacing = !isSpaceOrNewline(rt->characters()[r->m_stop - 1]) && r->m_stop == length;
            }

            setLogicalWidthForTextRun(lineBox, r, rt, totalLogicalWidth, lineInfo, textBoxDataMap, verticalPositionCache);
        } else {
            isAfterExpansion = false;
            if (!r->m_object->isRenderInline()) {
                RenderBox* renderBox = toRenderBox(r->m_object);
                if (renderBox->isRubyRun())
                    setMarginsForRubyRun(r, toRenderRubyRun(renderBox), previousObject, lineInfo);
                r->m_box->setLogicalWidth(logicalWidthForChild(renderBox));
                totalLogicalWidth += marginStartForChild(renderBox) + marginEndForChild(renderBox);
            }
        }

        totalLogicalWidth += r->m_box->logicalWidth();
        previousObject = r->m_object;
    }

    if (isAfterExpansion && !expansionOpportunities.isEmpty()) {
        expansionOpportunities.last()--;
        expansionOpportunityCount--;
    }

    // Armed with the total width of the line (without justification),
    // we now examine our text-align property in order to determine where to position the
    // objects horizontally.  The total width of the line can be increased if we end up
    // justifying text.
    switch (textAlign) {
        case LEFT:
        case WEBKIT_LEFT:
            updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            break;
        case JUSTIFY:
            adjustInlineDirectionLineBounds(expansionOpportunityCount, logicalLeft, availableLogicalWidth);
            if (expansionOpportunityCount) {
                if (trailingSpaceRun) {
                    totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
                    trailingSpaceRun->m_box->setLogicalWidth(0);
                }
                break;
            }
            // fall through
        case TAAUTO:
            // for right to left fall through to right aligned
            if (style()->isLeftToRightDirection()) {
                if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun)
                    trailingSpaceRun->m_box->setLogicalWidth(max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
                break;
            }
        case RIGHT:
        case WEBKIT_RIGHT:
            updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            break;
        case CENTER:
        case WEBKIT_CENTER:
            updateLogicalWidthForCenterAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            break;
        case TASTART:
            if (style()->isLeftToRightDirection())
                updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            else
                updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            break;
        case TAEND:
            if (style()->isLeftToRightDirection())
                updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            else
                updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
            break;
    }

    computeExpansionForJustifiedText(firstRun, trailingSpaceRun, expansionOpportunities, expansionOpportunityCount, totalLogicalWidth, availableLogicalWidth);

    // The widths of all runs are now known.  We can now place every inline box (and
    // compute accurate widths for the inline flow boxes).
    needsWordSpacing = false;
    lineBox->placeBoxesInInlineDirection(logicalLeft, needsWordSpacing, textBoxDataMap);
}

void RenderBlock::computeBlockDirectionPositionsForLine(RootInlineBox* lineBox, BidiRun* firstRun, GlyphOverflowAndFallbackFontsMap& textBoxDataMap,
                                                        VerticalPositionCache& verticalPositionCache)
{
    setLogicalHeight(lineBox->alignBoxesInBlockDirection(logicalHeight(), textBoxDataMap, verticalPositionCache));
    lineBox->setBlockLogicalHeight(logicalHeight());

    // Now make sure we place replaced render objects correctly.
    for (BidiRun* r = firstRun; r; r = r->next()) {
        ASSERT(r->m_box);
        if (!r->m_box)
            continue; // Skip runs with no line boxes.

        // Align positioned boxes with the top of the line box.  This is
        // a reasonable approximation of an appropriate y position.
        if (r->m_object->isPositioned())
            r->m_box->setLogicalTop(logicalHeight());

        // Position is used to properly position both replaced elements and
        // to update the static normal flow x/y of positioned elements.
        if (r->m_object->isText())
            toRenderText(r->m_object)->positionLineBox(r->m_box);
        else if (r->m_object->isBox())
            toRenderBox(r->m_object)->positionLineBox(r->m_box);
    }
    // Positioned objects and zero-length text nodes destroy their boxes in
    // position(), which unnecessarily dirties the line.
    lineBox->markDirty(false);
}

static inline bool isCollapsibleSpace(UChar character, RenderText* renderer)
{
    if (character == ' ' || character == '\t' || character == softHyphen)
        return true;
    if (character == '\n')
        return !renderer->style()->preserveNewline();
    if (character == noBreakSpace)
        return renderer->style()->nbspMode() == SPACE;
    return false;
}


static void setStaticPositions(RenderBlock* block, RenderBox* child)
{
    // FIXME: The math here is actually not really right. It's a best-guess approximation that
    // will work for the common cases
    RenderObject* containerBlock = child->container();
    int blockHeight = block->logicalHeight();
    if (containerBlock->isRenderInline()) {
        // A relative positioned inline encloses us. In this case, we also have to determine our
        // position as though we were an inline. Set |staticInlinePosition| and |staticBlockPosition| on the relative positioned
        // inline so that we can obtain the value later.
        toRenderInline(containerBlock)->layer()->setStaticInlinePosition(block->startOffsetForLine(blockHeight, false));
        toRenderInline(containerBlock)->layer()->setStaticBlockPosition(blockHeight);
    }

    if (child->style()->isOriginalDisplayInlineType())
        child->layer()->setStaticInlinePosition(block->startOffsetForLine(blockHeight, false));
    else
        child->layer()->setStaticInlinePosition(block->borderAndPaddingStart());
    child->layer()->setStaticBlockPosition(blockHeight);
}

inline BidiRun* RenderBlock::handleTrailingSpaces(BidiRunList<BidiRun>& bidiRuns, BidiContext* currentContext)
{
    if (!bidiRuns.runCount()
        || !bidiRuns.logicallyLastRun()->m_object->style()->breakOnlyAfterWhiteSpace()
        || !bidiRuns.logicallyLastRun()->m_object->style()->autoWrap())
        return 0;

    BidiRun* trailingSpaceRun = bidiRuns.logicallyLastRun();
    RenderObject* lastObject = trailingSpaceRun->m_object;
    if (!lastObject->isText())
        return 0;

    RenderText* lastText = toRenderText(lastObject);
    const UChar* characters = lastText->characters();
    int firstSpace = trailingSpaceRun->stop();
    while (firstSpace > trailingSpaceRun->start()) {
        UChar current = characters[firstSpace - 1];
        if (!isCollapsibleSpace(current, lastText))
            break;
        firstSpace--;
    }
    if (firstSpace == trailingSpaceRun->stop())
        return 0;

    TextDirection direction = style()->direction();
    bool shouldReorder = trailingSpaceRun != (direction == LTR ? bidiRuns.lastRun() : bidiRuns.firstRun());
    if (firstSpace != trailingSpaceRun->start()) {
        BidiContext* baseContext = currentContext;
        while (BidiContext* parent = baseContext->parent())
            baseContext = parent;

        BidiRun* newTrailingRun = new (renderArena()) BidiRun(firstSpace, trailingSpaceRun->m_stop, trailingSpaceRun->m_object, baseContext, OtherNeutral);
        trailingSpaceRun->m_stop = firstSpace;
        if (direction == LTR)
            bidiRuns.addRun(newTrailingRun);
        else
            bidiRuns.prependRun(newTrailingRun);
        trailingSpaceRun = newTrailingRun;
        return trailingSpaceRun;
    }
    if (!shouldReorder)
        return trailingSpaceRun;

    if (direction == LTR) {
        bidiRuns.moveRunToEnd(trailingSpaceRun);
        trailingSpaceRun->m_level = 0;
    } else {
        bidiRuns.moveRunToBeginning(trailingSpaceRun);
        trailingSpaceRun->m_level = 1;
    }
    return trailingSpaceRun;
}

void RenderBlock::appendFloatingObjectToLastLine(FloatingObject* floatingObject)
{
    ASSERT(!floatingObject->m_originatingLine);
    floatingObject->m_originatingLine = lastRootBox();
    lastRootBox()->appendFloat(floatingObject->renderer());
}

// This function constructs line boxes for all of the text runs in the resolver and computes their position.
RootInlineBox* RenderBlock::createLineBoxesFromBidiRuns(BidiRunList<BidiRun>& bidiRuns, const InlineIterator& end, LineInfo& lineInfo, VerticalPositionCache& verticalPositionCache, BidiRun* trailingSpaceRun)
{
    if (!bidiRuns.runCount())
        return 0;

    // FIXME: Why is this only done when we had runs?
    lineInfo.setLastLine(!end.m_obj);

    RootInlineBox* lineBox = constructLine(bidiRuns, lineInfo);
    if (!lineBox)
        return 0;

    lineBox->setEndsWithBreak(lineInfo.previousLineBrokeCleanly());
    
#if ENABLE(SVG)
    bool isSVGRootInlineBox = lineBox->isSVGRootInlineBox();
#else
    bool isSVGRootInlineBox = false;
#endif
    
    GlyphOverflowAndFallbackFontsMap textBoxDataMap;
    
    // Now we position all of our text runs horizontally.
    if (!isSVGRootInlineBox)
        computeInlineDirectionPositionsForLine(lineBox, lineInfo, bidiRuns.firstRun(), trailingSpaceRun, end.atEnd(), textBoxDataMap, verticalPositionCache);
    
    // Now position our text runs vertically.
    computeBlockDirectionPositionsForLine(lineBox, bidiRuns.firstRun(), textBoxDataMap, verticalPositionCache);
    
#if ENABLE(SVG)
    // SVG text layout code computes vertical & horizontal positions on its own.
    // Note that we still need to execute computeVerticalPositionsForLine() as
    // it calls InlineTextBox::positionLineBox(), which tracks whether the box
    // contains reversed text or not. If we wouldn't do that editing and thus
    // text selection in RTL boxes would not work as expected.
    if (isSVGRootInlineBox) {
        ASSERT(isSVGText());
        static_cast<SVGRootInlineBox*>(lineBox)->computePerCharacterLayoutInformation();
    }
#endif
    
    // Compute our overflow now.
    lineBox->computeOverflow(lineBox->lineTop(), lineBox->lineBottom(), textBoxDataMap);
    
#if PLATFORM(MAC)
    // Highlight acts as an overflow inflation.
    if (style()->highlight() != nullAtom)
        lineBox->addHighlightOverflow();
#endif
    return lineBox;
}

void RenderBlock::layoutRunsAndFloats(bool fullLayout, bool hasInlineChild, Vector<FloatWithRect>& floats, int& repaintLogicalTop, int& repaintLogicalBottom)
{
    // We want to skip ahead to the first dirty line
    InlineBidiResolver resolver;
    unsigned floatIndex;
    LineInfo lineInfo;
    bool useRepaintBounds = false;

    RootInlineBox* startLine = determineStartPosition(lineInfo, fullLayout, resolver, floats, floatIndex,
                                                      useRepaintBounds, repaintLogicalTop, repaintLogicalBottom);

    // FIXME: This would make more sense outside of this function, but since
    // determineStartPosition can change the fullLayout flag we have to do this here. Failure to call
    // determineStartPosition first will break fast/repaint/line-flow-with-floats-9.html.
    if (fullLayout && hasInlineChild && !selfNeedsLayout()) {
        setNeedsLayout(true, false);  // Mark ourselves as needing a full layout. This way we'll repaint like
        // we're supposed to.
        RenderView* v = view();
        if (v && !v->doingFullRepaint() && hasLayer()) {
            // Because we waited until we were already inside layout to discover
            // that the block really needed a full layout, we missed our chance to repaint the layer
            // before layout started.  Luckily the layer has cached the repaint rect for its original
            // position and size, and so we can use that to make a repaint happen now.
            repaintUsingContainer(containerForRepaint(), layer()->repaintRect());
        }
    }

    FloatingObject* lastFloat = (m_floatingObjects && !m_floatingObjects->set().isEmpty()) ? m_floatingObjects->set().last() : 0;

    LineMidpointState& lineMidpointState = resolver.midpointState();

    // We also find the first clean line and extract these lines.  We will add them back
    // if we determine that we're able to synchronize after handling all our dirty lines.
    InlineIterator cleanLineStart;
    BidiStatus cleanLineBidiStatus;
    int endLineLogicalTop = 0;
    RootInlineBox* endLine = (fullLayout || !startLine) ?
        0 : determineEndPosition(startLine, floats, floatIndex, cleanLineStart, cleanLineBidiStatus, endLineLogicalTop);

    if (startLine) {
        if (!useRepaintBounds) {
            useRepaintBounds = true;
            repaintLogicalTop = logicalHeight();
            repaintLogicalBottom = logicalHeight();
        }
        RenderArena* arena = renderArena();
        RootInlineBox* box = startLine;
        while (box) {
            repaintLogicalTop = min(repaintLogicalTop, box->logicalTopVisualOverflow());
            repaintLogicalBottom = max(repaintLogicalBottom, box->logicalBottomVisualOverflow());
            RootInlineBox* next = box->nextRootBox();
            box->deleteLine(arena);
            box = next;
        }
    }

    InlineIterator end = resolver.position();

    if (!fullLayout && lastRootBox() && lastRootBox()->endsWithBreak()) {
        // If the last line before the start line ends with a line break that clear floats,
        // adjust the height accordingly.
        // A line break can be either the first or the last object on a line, depending on its direction.
        if (InlineBox* lastLeafChild = lastRootBox()->lastLeafChild()) {
            RenderObject* lastObject = lastLeafChild->renderer();
            if (!lastObject->isBR())
                lastObject = lastRootBox()->firstLeafChild()->renderer();
            if (lastObject->isBR()) {
                EClear clear = lastObject->style()->clear();
                if (clear != CNONE)
                    newLine(clear);
            }
        }
    }

    bool endLineMatched = false;
    bool checkForEndLineMatch = endLine;
    bool checkForFloatsFromLastLine = false;

    bool paginated = view()->layoutState() && view()->layoutState()->isPaginated();

    LineBreakIteratorInfo lineBreakIteratorInfo;
    VerticalPositionCache verticalPositionCache;

    LineBreaker lineBreaker(this);

    while (!end.atEnd()) {
        // FIXME: Is this check necessary before the first iteration or can it be moved to the end?
        if (checkForEndLineMatch && (endLineMatched = matchedEndLine(resolver, cleanLineStart, cleanLineBidiStatus, endLine, endLineLogicalTop, repaintLogicalBottom, repaintLogicalTop)))
            break;

        lineMidpointState.reset();

        lineInfo.setEmpty(true);

        InlineIterator oldEnd = end;
        FloatingObject* lastFloatFromPreviousLine = (m_floatingObjects && !m_floatingObjects->set().isEmpty()) ? m_floatingObjects->set().last() : 0;
        end = lineBreaker.nextLineBreak(resolver, lineInfo, lineBreakIteratorInfo, lastFloatFromPreviousLine);
        if (resolver.position().atEnd()) {
            // FIXME: We shouldn't be creating any runs in findNextLineBreak to begin with!
            // Once BidiRunList is separated from BidiResolver this will not be needed.
            resolver.runs().deleteRuns();
            resolver.markCurrentRunEmpty(); // FIXME: This can probably be replaced by an ASSERT (or just removed).
            checkForFloatsFromLastLine = true;
            break;
        }
        ASSERT(end != resolver.position());

        // This is a short-cut for empty lines.
        if (lineInfo.isEmpty()) {
            if (lastRootBox())
                lastRootBox()->setLineBreakInfo(end.m_obj, end.m_pos, resolver.status());
        } else {
            VisualDirectionOverride override = (style()->visuallyOrdered() ? (style()->direction() == LTR ? VisualLeftToRightOverride : VisualRightToLeftOverride) : NoVisualOverride);
            // FIXME: This ownership is reversed. We should own the BidiRunList and pass it to createBidiRunsForLine.
            BidiRunList<BidiRun>& bidiRuns = resolver.runs();
            resolver.createBidiRunsForLine(end, override, lineInfo.previousLineBrokeCleanly());
            ASSERT(resolver.position() == end);

            BidiRun* trailingSpaceRun = !lineInfo.previousLineBrokeCleanly() ? handleTrailingSpaces(bidiRuns, resolver.context()) : 0;

            if (bidiRuns.runCount() && lineBreaker.lineWasHyphenated())
                bidiRuns.logicallyLastRun()->m_hasHyphen = true;

            // Now that the runs have been ordered, we create the line boxes.
            // At the same time we figure out where border/padding/margin should be applied for
            // inline flow boxes.

            int oldLogicalHeight = logicalHeight();
            RootInlineBox* lineBox = createLineBoxesFromBidiRuns(bidiRuns, end, lineInfo, verticalPositionCache, trailingSpaceRun);

            bidiRuns.deleteRuns();
            resolver.markCurrentRunEmpty(); // FIXME: This can probably be replaced by an ASSERT (or just removed).

            if (lineBox) {
                lineBox->setLineBreakInfo(end.m_obj, end.m_pos, resolver.status());
                if (useRepaintBounds) {
                    repaintLogicalTop = min(repaintLogicalTop, lineBox->logicalTopVisualOverflow());
                    repaintLogicalBottom = max(repaintLogicalBottom, lineBox->logicalBottomVisualOverflow());
                }

                if (paginated) {
                    int adjustment = 0;
                    adjustLinePositionForPagination(lineBox, adjustment);
                    if (adjustment) {
                        int oldLineWidth = availableLogicalWidthForLine(oldLogicalHeight, lineInfo.isFirstLine());
                        lineBox->adjustBlockDirectionPosition(adjustment);
                        if (useRepaintBounds) // This can only be a positive adjustment, so no need to update repaintTop.
                            repaintLogicalBottom = max(repaintLogicalBottom, lineBox->logicalBottomVisualOverflow());

                        if (availableLogicalWidthForLine(oldLogicalHeight + adjustment, lineInfo.isFirstLine()) != oldLineWidth) {
                            // We have to delete this line, remove all floats that got added, and let line layout re-run.
                            lineBox->deleteLine(renderArena());
                            removeFloatingObjectsBelow(lastFloatFromPreviousLine, oldLogicalHeight);
                            setLogicalHeight(oldLogicalHeight + adjustment);
                            resolver.setPosition(oldEnd);
                            end = oldEnd;
                            continue;
                        }

                        setLogicalHeight(lineBox->blockLogicalHeight());
                    }
                }
            }

            for (size_t i = 0; i < lineBreaker.positionedObjects().size(); ++i)
                setStaticPositions(this, lineBreaker.positionedObjects()[i]);

            lineInfo.setFirstLine(false);
            newLine(lineBreaker.clear());
        }

        if (m_floatingObjects && lastRootBox()) {
            FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
            FloatingObjectSetIterator it = floatingObjectSet.begin();
            FloatingObjectSetIterator end = floatingObjectSet.end();
            if (lastFloat) {
                FloatingObjectSetIterator lastFloatIterator = floatingObjectSet.find(lastFloat);
                ASSERT(lastFloatIterator != end);
                ++lastFloatIterator;
                it = lastFloatIterator;
            }
            for (; it != end; ++it) {
                FloatingObject* f = *it;
                appendFloatingObjectToLastLine(f);
                ASSERT(f->m_renderer == floats[floatIndex].object);
                // If a float's geometry has changed, give up on syncing with clean lines.
                if (floats[floatIndex].rect != f->frameRect())
                    checkForEndLineMatch = false;
                floatIndex++;
            }
            lastFloat = !floatingObjectSet.isEmpty() ? floatingObjectSet.last() : 0;
        }

        lineMidpointState.reset();
        resolver.setPosition(end);
    }

    if (endLine) {
        if (endLineMatched) {
            // Attach all the remaining lines, and then adjust their y-positions as needed.
            int delta = logicalHeight() - endLineLogicalTop;
            for (RootInlineBox* line = endLine; line; line = line->nextRootBox()) {
                line->attachLine();
                if (paginated) {
                    delta -= line->paginationStrut();
                    adjustLinePositionForPagination(line, delta);
                }
                if (delta) {
                    repaintLogicalTop = min(repaintLogicalTop, line->logicalTopVisualOverflow() + min(delta, 0));
                    repaintLogicalBottom = max(repaintLogicalBottom, line->logicalBottomVisualOverflow() + max(delta, 0));
                    line->adjustBlockDirectionPosition(delta);
                }
                if (Vector<RenderBox*>* cleanLineFloats = line->floatsPtr()) {
                    Vector<RenderBox*>::iterator end = cleanLineFloats->end();
                    for (Vector<RenderBox*>::iterator f = cleanLineFloats->begin(); f != end; ++f) {
                        FloatingObject* floatingObject = insertFloatingObject(*f);
                        ASSERT(!floatingObject->m_originatingLine);
                        floatingObject->m_originatingLine = line;
                        setLogicalHeight(logicalTopForChild(*f) - marginBeforeForChild(*f) + delta);
                        positionNewFloats();
                    }
                }
            }
            setLogicalHeight(lastRootBox()->blockLogicalHeight());
        } else {
            // Delete all the remaining lines.
            RootInlineBox* line = endLine;
            RenderArena* arena = renderArena();
            while (line) {
                repaintLogicalTop = min(repaintLogicalTop, line->logicalTopVisualOverflow());
                repaintLogicalBottom = max(repaintLogicalBottom, line->logicalBottomVisualOverflow());
                RootInlineBox* next = line->nextRootBox();
                line->deleteLine(arena);
                line = next;
            }
        }
    }
    if (m_floatingObjects && (checkForFloatsFromLastLine || positionNewFloats()) && lastRootBox()) {
        // In case we have a float on the last line, it might not be positioned up to now.
        // This has to be done before adding in the bottom border/padding, or the float will
        // include the padding incorrectly. -dwh
        if (checkForFloatsFromLastLine) {
            int bottomVisualOverflow = lastRootBox()->logicalBottomVisualOverflow();
            int bottomLayoutOverflow = lastRootBox()->logicalBottomLayoutOverflow();
            TrailingFloatsRootInlineBox* trailingFloatsLineBox = new (renderArena()) TrailingFloatsRootInlineBox(this);
            m_lineBoxes.appendLineBox(trailingFloatsLineBox);
            trailingFloatsLineBox->setConstructed();
            GlyphOverflowAndFallbackFontsMap textBoxDataMap;
            VerticalPo…