bidi.cpp

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    switch(textAlign) {
        case LEFT:
        case WEBKIT_LEFT:
            // 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 (style()->direction() == LTR) {
                if (totWidth > availableWidth && trailingSpaceRun)
                    trailingSpaceRun->m_box->setWidth(trailingSpaceRun->m_box->width() - totWidth + availableWidth);
            } else {
                if (trailingSpaceRun)
                    trailingSpaceRun->m_box->setWidth(0);
                else if (totWidth > availableWidth)
                    x -= (totWidth - availableWidth);
            }
            break;
        case JUSTIFY:
            if (numSpaces && !reachedEnd && !lineBox->endsWithBreak()) {
                if (trailingSpaceRun) {
                    totWidth -= trailingSpaceRun->m_box->width();
                    trailingSpaceRun->m_box->setWidth(0);
                }
                break;
            }
            // fall through
        case TAAUTO:
            numSpaces = 0;
            // for right to left fall through to right aligned
            if (style()->direction() == LTR) {
                if (totWidth > availableWidth && trailingSpaceRun)
                    trailingSpaceRun->m_box->setWidth(trailingSpaceRun->m_box->width() - totWidth + availableWidth);
                break;
            }
        case RIGHT:
        case WEBKIT_RIGHT:
            // 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 (style()->direction() == LTR) {
                if (trailingSpaceRun) {
                    totWidth -= trailingSpaceRun->m_box->width();
                    trailingSpaceRun->m_box->setWidth(0);
                }
                if (totWidth < availableWidth)
                    x += availableWidth - totWidth;
            } else {
                if (totWidth > availableWidth && trailingSpaceRun) {
                    trailingSpaceRun->m_box->setWidth(trailingSpaceRun->m_box->width() - totWidth + availableWidth);
                    totWidth -= trailingSpaceRun->m_box->width();
                } else
                    x += availableWidth - totWidth;
            }
            break;
        case CENTER:
        case WEBKIT_CENTER:
            int trailingSpaceWidth = 0;
            if (trailingSpaceRun) {
                totWidth -= trailingSpaceRun->m_box->width();
                trailingSpaceWidth = min(trailingSpaceRun->m_box->width(), (availableWidth - totWidth + 1) / 2);
                trailingSpaceRun->m_box->setWidth(trailingSpaceWidth);
            }
            if (style()->direction() == LTR)
                x += max((availableWidth - totWidth) / 2, 0);
            else
                x += totWidth > availableWidth ? (availableWidth - totWidth) : (availableWidth - totWidth) / 2 - trailingSpaceWidth;
            break;
    }

    if (numSpaces) {
        for (BidiRun* r = firstRun; r; r = r->next()) {
            if (!r->m_box || r == trailingSpaceRun)
                continue;

            int spaceAdd = 0;
            if (r->m_object->isText()) {
                unsigned spaces = 0;
                const UChar* characters = toRenderText(r->m_object)->characters();
                for (int i = r->m_start; i < r->m_stop; i++) {
                    UChar c = characters[i];
                    if (c == ' ' || c == '\n' || c == '\t')
                        spaces++;
                }

                ASSERT(spaces <= numSpaces);

                // Only justify text if whitespace is collapsed.
                if (r->m_object->style()->collapseWhiteSpace()) {
                    spaceAdd = (availableWidth - totWidth) * spaces / numSpaces;
                    static_cast<InlineTextBox*>(r->m_box)->setSpaceAdd(spaceAdd);
                    totWidth += spaceAdd;
                }
                numSpaces -= spaces;
                if (!numSpaces)
                    break;
            }
        }
    }

    // The widths of all runs are now known.  We can now place every inline box (and
    // compute accurate widths for the inline flow boxes).
    int leftPosition = x;
    int rightPosition = x;
    needsWordSpacing = false;
    lineBox->placeBoxesHorizontally(x, leftPosition, rightPosition, needsWordSpacing);
    lineBox->setHorizontalOverflowPositions(leftPosition, rightPosition);
}

void RenderBlock::computeVerticalPositionsForLine(RootInlineBox* lineBox, BidiRun* firstRun)
{
    setHeight(lineBox->verticallyAlignBoxes(height()));
    lineBox->setBlockHeight(height());

    // See if the line spilled out.  If so set overflow height accordingly.
    int bottomOfLine = lineBox->bottomOverflow();
    if (bottomOfLine > height() && bottomOfLine > m_overflowHeight)
        m_overflowHeight = bottomOfLine;

    // Now make sure we place replaced render objects correctly.
    for (BidiRun* r = firstRun; r; r = r->next()) {
        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->setY(height());

        // 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);
}

// collects one line of the paragraph and transforms it to visual order
void RenderBlock::bidiReorderLine(InlineBidiResolver& resolver, const InlineIterator& end)
{
    resolver.createBidiRunsForLine(end, style()->visuallyOrdered(), previousLineBrokeCleanly);
}

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;
}

void RenderBlock::layoutInlineChildren(bool relayoutChildren, int& repaintTop, int& repaintBottom)
{
    bool useRepaintBounds = false;
    
    m_overflowHeight = 0;
        
    setHeight(borderTop() + paddingTop());
    int toAdd = borderBottom() + paddingBottom() + horizontalScrollbarHeight();

    // Figure out if we should clear out our line boxes.
    // FIXME: Handle resize eventually!
    // FIXME: Do something better when floats are present.
    bool fullLayout = !firstLineBox() || !firstChild() || selfNeedsLayout() || relayoutChildren;
    if (fullLayout)
        lineBoxes()->deleteLineBoxes(renderArena());

    // Text truncation only kicks in if your overflow isn't visible and your text-overflow-mode isn't
    // clip.
    // FIXME: CSS3 says that descendants that are clipped must also know how to truncate.  This is insanely
    // difficult to figure out (especially in the middle of doing layout), and is really an esoteric pile of nonsense
    // anyway, so we won't worry about following the draft here.
    bool hasTextOverflow = style()->textOverflow() && hasOverflowClip();

    // Walk all the lines and delete our ellipsis line boxes if they exist.
    if (hasTextOverflow)
         deleteEllipsisLineBoxes();

    if (firstChild()) {
        // layout replaced elements
        bool endOfInline = false;
        RenderObject* o = bidiFirst(this, 0, false);
        Vector<FloatWithRect> floats;
        while (o) {
            if (o->isReplaced() || o->isFloating() || o->isPositioned()) {
                RenderBox* box = toRenderBox(o);
                
                if (relayoutChildren || o->style()->width().isPercent() || o->style()->height().isPercent())
                    o->setChildNeedsLayout(true, false);
                    
                // If relayoutChildren is set and we have percentage padding, we also need to invalidate the child's pref widths.
                if (relayoutChildren && (o->style()->paddingLeft().isPercent() || o->style()->paddingRight().isPercent()))
                    o->setPrefWidthsDirty(true, false);
            
                if (o->isPositioned())
                    o->containingBlock()->insertPositionedObject(box);
                else {
                    if (o->isFloating())
                        floats.append(FloatWithRect(box));
                    else if (fullLayout || o->needsLayout()) // Replaced elements
                        toRenderBox(o)->dirtyLineBoxes(fullLayout);

                    o->layoutIfNeeded();
                }
            } else if (o->isText() || (o->isRenderInline() && !endOfInline)) {
                if (fullLayout || o->selfNeedsLayout())
                    dirtyLineBoxesForRenderer(o, fullLayout);
                o->setNeedsLayout(false);
                if (!o->isText())
                    toRenderInline(o)->invalidateVerticalPosition(); // FIXME: Should do better here and not always invalidate everything.
            }
            o = bidiNext(this, o, 0, false, &endOfInline);
        }

        // We want to skip ahead to the first dirty line
        InlineBidiResolver resolver;
        unsigned floatIndex;
        bool firstLine = true;
        RootInlineBox* startLine = determineStartPosition(firstLine, fullLayout, resolver, floats, floatIndex);

        if (fullLayout && !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->last() : 0;

        if (!smidpoints)
            smidpoints = new Vector<InlineIterator>();

        sNumMidpoints = 0;
        sCurrMidpoint = 0;

        // 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 endLineYPos = 0;
        RootInlineBox* endLine = (fullLayout || !startLine) ? 
                                 0 : determineEndPosition(startLine, cleanLineStart, cleanLineBidiStatus, endLineYPos);

        if (startLine) {
            useRepaintBounds = true;
            repaintTop = height();
            repaintBottom = height();
            RenderArena* arena = renderArena();
            RootInlineBox* box = startLine;
            while (box) {
                repaintTop = min(repaintTop, box->topOverflow());
                repaintBottom = max(repaintBottom, box->bottomOverflow());
                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;
        int lastHeight = height();

        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, endLineYPos, repaintBottom, repaintTop)))
                break;

            betweenMidpoints = false;
            isLineEmpty = true;
            
            EClear clear = CNONE;
            end = findNextLineBreak(resolver, firstLine, &clear);
            if (resolver.position().atEnd()) {
                resolver.deleteRuns();
                checkForFloatsFromLastLine = true;
                break;
            }
            ASSERT(end != resolver.position());

            if (!isLineEmpty) {
                bidiReorderLine(resolver, end);
                ASSERT(resolver.position() == end);

                BidiRun* trailingSpaceRun = 0;
                if (!previousLineBrokeCleanly && resolver.runCount() && resolver.logicallyLastRun()->m_object->style()->breakOnlyAfterWhiteSpace()) {
                    trailingSpaceRun = resolver.logicallyLastRun();
                    RenderObject* lastObject = trailingSpaceRun->m_object;
                    if (lastObject->isText()) {
                        RenderText* lastText = toRenderText(lastObject);
                        const UChar* characters = lastText->characters();
                        int firstSpace = trailingSpaceRun->stop();
                        while (firstSpace > trailingSpaceRun->start()) {