Source/core/rendering/RenderText.cpp

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This source file includes following definitions.
m_lastTypedCharacterOffset
restartWithNewText
invalidate
lastTypedCharacterOffset
fired
makeCapitalized
m_lastTextBox
renderName
isTextFragment
isWordBreak
styleDidChange
removeAndDestroyTextBoxes
willBeDestroyed
extractTextBox
attachTextBox
removeTextBox
deleteTextBoxes
originalText
plainText
absoluteRects
localQuadForTextBox
absoluteRectsForRange
ellipsisRectForBox
absoluteQuads
absoluteQuads
absoluteQuadsForRange
findNextInlineTextBox
lineDirectionPointFitsInBox
createPositionWithAffinityForBox
createPositionWithAffinityForBoxAfterAdjustingOffsetForBiDi
positionForPoint
localCaretRect
widthFromCache
trimmedPrefWidths
minLogicalWidth
maxLogicalWidth
computePreferredLogicalWidths
hyphenWidth
computePreferredLogicalWidths
isAllCollapsibleWhitespace
containsOnlyWhitespace
firstRunOrigin
firstRunX
firstRunY
setSelectionState
setTextWithOffset
transformText
isInlineFlowOrEmptyText
previousCharacter
addLayerHitTestRects
applyTextTransform
setTextInternal
secureText
setText
dirtyLineBoxes
createTextBox
createInlineTextBox
positionLineBox
width
width
linesBoundingBox
linesVisualOverflowBoundingBox
clippedOverflowRectForRepaint
selectionRectForRepaint
caretMinOffset
caretMaxOffset
renderedTextLength
previousOffset
isHangulLVT
isMark
isRegionalIndicator
previousOffsetForBackwardDeletion
nextOffset
computeCanUseSimpleFontCodePath
checkConsistency
momentarilyRevealLastTypedCharacter
firstAbstractInlineTextBox
/*
 * (C) 1999 Lars Knoll (knoll@kde.org)
 * (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
 * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.com)
 *
 * 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 "core/rendering/RenderText.h"

#include "core/accessibility/AXObjectCache.h"
#include "core/dom/Text.h"
#include "core/editing/TextIterator.h"
#include "core/frame/FrameView.h"
#include "core/frame/Settings.h"
#include "core/html/parser/TextResourceDecoder.h"
#include "core/rendering/AbstractInlineTextBox.h"
#include "core/rendering/EllipsisBox.h"
#include "core/rendering/InlineTextBox.h"
#include "core/rendering/RenderBlock.h"
#include "core/rendering/RenderCombineText.h"
#include "core/rendering/RenderLayer.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/break_lines.h"
#include "platform/fonts/Character.h"
#include "platform/geometry/FloatQuad.h"
#include "platform/text/BidiResolver.h"
#include "platform/text/TextBreakIterator.h"
#include "platform/text/TextRunIterator.h"
#include "wtf/text/StringBuffer.h"
#include "wtf/text/StringBuilder.h"
#include "wtf/unicode/CharacterNames.h"

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

namespace WebCore {

struct SameSizeAsRenderText : public RenderObject {
    uint32_t bitfields : 16;
    float widths[4];
    String text;
    void* pointers[2];
};

COMPILE_ASSERT(sizeof(RenderText) == sizeof(SameSizeAsRenderText), RenderText_should_stay_small);

class SecureTextTimer;
typedef HashMap<RenderText*, SecureTextTimer*> SecureTextTimerMap;
static SecureTextTimerMap* gSecureTextTimers = 0;

class SecureTextTimer FINAL : public TimerBase {
public:
    SecureTextTimer(RenderText* renderText)
        : m_renderText(renderText)
        , m_lastTypedCharacterOffset(-1)
    {
    }

    void restartWithNewText(unsigned lastTypedCharacterOffset)
    {
        m_lastTypedCharacterOffset = lastTypedCharacterOffset;
        if (Settings* settings = m_renderText->document().settings())
            startOneShot(settings->passwordEchoDurationInSeconds(), FROM_HERE);
    }
    void invalidate() { m_lastTypedCharacterOffset = -1; }
    unsigned lastTypedCharacterOffset() { return m_lastTypedCharacterOffset; }

private:
    virtual void fired() OVERRIDE
    {
        ASSERT(gSecureTextTimers->contains(m_renderText));
        m_renderText->setText(m_renderText->text().impl(), true /* forcing setting text as it may be masked later */);
    }

    RenderText* m_renderText;
    int m_lastTypedCharacterOffset;
};

static void makeCapitalized(String* string, UChar previous)
{
    if (string->isNull())
        return;

    unsigned length = string->length();
    const StringImpl& input = *string->impl();

    if (length >= numeric_limits<unsigned>::max())
        CRASH();

    StringBuffer<UChar> stringWithPrevious(length + 1);
    stringWithPrevious[0] = previous == noBreakSpace ? ' ' : previous;
    for (unsigned i = 1; i < length + 1; i++) {
        // Replace &nbsp with a real space since ICU no longer treats &nbsp as a word separator.
        if (input[i - 1] == noBreakSpace)
            stringWithPrevious[i] = ' ';
        else
            stringWithPrevious[i] = input[i - 1];
    }

    TextBreakIterator* boundary = wordBreakIterator(stringWithPrevious.characters(), length + 1);
    if (!boundary)
        return;

    StringBuilder result;
    result.reserveCapacity(length);

    int32_t endOfWord;
    int32_t startOfWord = boundary->first();
    for (endOfWord = boundary->next(); endOfWord != TextBreakDone; startOfWord = endOfWord, endOfWord = boundary->next()) {
        if (startOfWord) // Ignore first char of previous string
            result.append(input[startOfWord - 1] == noBreakSpace ? noBreakSpace : toTitleCase(stringWithPrevious[startOfWord]));
        for (int i = startOfWord + 1; i < endOfWord; i++)
            result.append(input[i - 1]);
    }

    *string = result.toString();
}

RenderText::RenderText(Node* node, PassRefPtr<StringImpl> str)
    : RenderObject(!node || node->isDocumentNode() ? 0 : node)
    , m_hasTab(false)
    , m_linesDirty(false)
    , m_containsReversedText(false)
    , m_knownToHaveNoOverflowAndNoFallbackFonts(false)
    , m_minWidth(-1)
    , m_maxWidth(-1)
    , m_firstLineMinWidth(0)
    , m_lastLineLineMinWidth(0)
    , m_text(str)
    , m_firstTextBox(0)
    , m_lastTextBox(0)
{
    ASSERT(m_text);
    // FIXME: Some clients of RenderText (and subclasses) pass Document as node to create anonymous renderer.
    // They should be switched to passing null and using setDocumentForAnonymous.
    if (node && node->isDocumentNode())
        setDocumentForAnonymous(toDocument(node));

    m_isAllASCII = m_text.containsOnlyASCII();
    m_canUseSimpleFontCodePath = computeCanUseSimpleFontCodePath();
    setIsText();

    view()->frameView()->incrementVisuallyNonEmptyCharacterCount(m_text.length());
}

#ifndef NDEBUG

RenderText::~RenderText()
{
    ASSERT(!m_firstTextBox);
    ASSERT(!m_lastTextBox);
}

#endif

const char* RenderText::renderName() const
{
    return "RenderText";
}

bool RenderText::isTextFragment() const
{
    return false;
}

bool RenderText::isWordBreak() const
{
    return false;
}

void RenderText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    // There is no need to ever schedule repaints from a style change of a text run, since
    // we already did this for the parent of the text run.
    // We do have to schedule layouts, though, since a style change can force us to
    // need to relayout.
    if (diff == StyleDifferenceLayout) {
        setNeedsLayoutAndPrefWidthsRecalc();
        m_knownToHaveNoOverflowAndNoFallbackFonts = false;
    }

    RenderStyle* newStyle = style();
    ETextTransform oldTransform = oldStyle ? oldStyle->textTransform() : TTNONE;
    ETextSecurity oldSecurity = oldStyle ? oldStyle->textSecurity() : TSNONE;
    if (oldTransform != newStyle->textTransform() || oldSecurity != newStyle->textSecurity())
        transformText();

    if (!text().containsOnlyWhitespace())
        newStyle->font().willUseFontData();
}

void RenderText::removeAndDestroyTextBoxes()
{
    if (!documentBeingDestroyed()) {
        if (firstTextBox()) {
            if (isBR()) {
                RootInlineBox* next = firstTextBox()->root().nextRootBox();
                if (next)
                    next->markDirty();
            }
            for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
                box->remove();
        } else if (parent())
            parent()->dirtyLinesFromChangedChild(this);
    }
    deleteTextBoxes();
}

void RenderText::willBeDestroyed()
{
    if (SecureTextTimer* secureTextTimer = gSecureTextTimers ? gSecureTextTimers->take(this) : 0)
        delete secureTextTimer;

    removeAndDestroyTextBoxes();
    RenderObject::willBeDestroyed();
}

void RenderText::extractTextBox(InlineTextBox* box)
{
    checkConsistency();

    m_lastTextBox = box->prevTextBox();
    if (box == m_firstTextBox)
        m_firstTextBox = 0;
    if (box->prevTextBox())
        box->prevTextBox()->setNextTextBox(0);
    box->setPreviousTextBox(0);
    for (InlineTextBox* curr = box; curr; curr = curr->nextTextBox())
        curr->setExtracted();

    checkConsistency();
}

void RenderText::attachTextBox(InlineTextBox* box)
{
    checkConsistency();

    if (m_lastTextBox) {
        m_lastTextBox->setNextTextBox(box);
        box->setPreviousTextBox(m_lastTextBox);
    } else
        m_firstTextBox = box;
    InlineTextBox* last = box;
    for (InlineTextBox* curr = box; curr; curr = curr->nextTextBox()) {
        curr->setExtracted(false);
        last = curr;
    }
    m_lastTextBox = last;

    checkConsistency();
}

void RenderText::removeTextBox(InlineTextBox* box)
{
    checkConsistency();

    if (box == m_firstTextBox)
        m_firstTextBox = box->nextTextBox();
    if (box == m_lastTextBox)
        m_lastTextBox = box->prevTextBox();
    if (box->nextTextBox())
        box->nextTextBox()->setPreviousTextBox(box->prevTextBox());
    if (box->prevTextBox())
        box->prevTextBox()->setNextTextBox(box->nextTextBox());

    checkConsistency();
}

void RenderText::deleteTextBoxes()
{
    if (firstTextBox()) {
        InlineTextBox* next;
        for (InlineTextBox* curr = firstTextBox(); curr; curr = next) {
            next = curr->nextTextBox();
            curr->destroy();
        }
        m_firstTextBox = m_lastTextBox = 0;
    }
}

PassRefPtr<StringImpl> RenderText::originalText() const
{
    Node* e = node();
    return (e && e->isTextNode()) ? toText(e)->dataImpl() : 0;
}

String RenderText::plainText() const
{
    if (node())
        return WebCore::plainText(rangeOfContents(node()).get());

    // FIXME: this is just a stopgap until TextIterator is adapted to support generated text.
    StringBuilder plainTextBuilder;
    for (InlineTextBox* textBox = firstTextBox(); textBox; textBox = textBox->nextTextBox()) {
        String text = m_text.substring(textBox->start(), textBox->len()).simplifyWhiteSpace(WTF::DoNotStripWhiteSpace);
        plainTextBuilder.append(text);
        if (textBox->nextTextBox() && textBox->nextTextBox()->start() > textBox->end() && text.length() && !text.right(1).containsOnlyWhitespace())
            plainTextBuilder.append(" ");
    }
    return plainTextBuilder.toString();
}

void RenderText::absoluteRects(Vector<IntRect>& rects, const LayoutPoint& accumulatedOffset) const
{
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
        rects.append(enclosingIntRect(FloatRect(accumulatedOffset + box->topLeft(), box->size())));
}

static FloatRect localQuadForTextBox(InlineTextBox* box, unsigned start, unsigned end, bool useSelectionHeight)
{
    unsigned realEnd = min(box->end() + 1, end);
    LayoutRect r = box->localSelectionRect(start, realEnd);
    if (r.height()) {
        if (!useSelectionHeight) {
            // Change the height and y position (or width and x for vertical text)
            // because selectionRect uses selection-specific values.
            if (box->isHorizontal()) {
                r.setHeight(box->height());
                r.setY(box->y());
            } else {
                r.setWidth(box->width());
                r.setX(box->x());
            }
        }
        return FloatRect(r);
    }
    return FloatRect();
}

void RenderText::absoluteRectsForRange(Vector<IntRect>& rects, unsigned start, unsigned end, bool useSelectionHeight, bool* wasFixed)
{
    // Work around signed/unsigned issues. This function takes unsigneds, and is often passed UINT_MAX
    // to mean "all the way to the end". InlineTextBox coordinates are unsigneds, so changing this
    // function to take ints causes various internal mismatches. But selectionRect takes ints, and
    // passing UINT_MAX to it causes trouble. Ideally we'd change selectionRect to take unsigneds, but
    // that would cause many ripple effects, so for now we'll just clamp our unsigned parameters to INT_MAX.
    ASSERT(end == UINT_MAX || end <= INT_MAX);
    ASSERT(start <= INT_MAX);
    start = min(start, static_cast<unsigned>(INT_MAX));
    end = min(end, static_cast<unsigned>(INT_MAX));

    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        // Note: box->end() returns the index of the last character, not the index past it
        if (start <= box->start() && box->end() < end) {
            FloatRect r = box->calculateBoundaries();
            if (useSelectionHeight) {
                LayoutRect selectionRect = box->localSelectionRect(start, end);
                if (box->isHorizontal()) {
                    r.setHeight(selectionRect.height().toFloat());
                    r.setY(selectionRect.y().toFloat());
                } else {
                    r.setWidth(selectionRect.width().toFloat());
                    r.setX(selectionRect.x().toFloat());
                }
            }
            rects.append(localToAbsoluteQuad(r, 0, wasFixed).enclosingBoundingBox());
        } else {
            // FIXME: This code is wrong. It's converting local to absolute twice. http://webkit.org/b/65722
            FloatRect rect = localQuadForTextBox(box, start, end, useSelectionHeight);
            if (!rect.isZero())
                rects.append(localToAbsoluteQuad(rect, 0, wasFixed).enclosingBoundingBox());
        }
    }
}

static IntRect ellipsisRectForBox(InlineTextBox* box, unsigned startPos, unsigned endPos)
{
    if (!box)
        return IntRect();

    unsigned short truncation = box->truncation();
    if (truncation == cNoTruncation)
        return IntRect();

    IntRect rect;
    if (EllipsisBox* ellipsis = box->root().ellipsisBox()) {
        int ellipsisStartPosition = max<int>(startPos - box->start(), 0);
        int ellipsisEndPosition = min<int>(endPos - box->start(), box->len());

        // The ellipsis should be considered to be selected if the end of
        // the selection is past the beginning of the truncation and the
        // beginning of the selection is before or at the beginning of the truncation.
        if (ellipsisEndPosition >= truncation && ellipsisStartPosition <= truncation)
            return ellipsis->selectionRect();
    }

    return IntRect();
}

void RenderText::absoluteQuads(Vector<FloatQuad>& quads, bool* wasFixed, ClippingOption option) const
{
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        FloatRect boundaries = box->calculateBoundaries();

        // Shorten the width of this text box if it ends in an ellipsis.
        // FIXME: ellipsisRectForBox should switch to return FloatRect soon with the subpixellayout branch.
        IntRect ellipsisRect = (option == ClipToEllipsis) ? ellipsisRectForBox(box, 0, textLength()) : IntRect();
        if (!ellipsisRect.isEmpty()) {
            if (style()->isHorizontalWritingMode())
                boundaries.setWidth(ellipsisRect.maxX() - boundaries.x());
            else
                boundaries.setHeight(ellipsisRect.maxY() - boundaries.y());
        }
        quads.append(localToAbsoluteQuad(boundaries, 0, wasFixed));
    }
}

void RenderText::absoluteQuads(Vector<FloatQuad>& quads, bool* wasFixed) const
{
    absoluteQuads(quads, wasFixed, NoClipping);
}

void RenderText::absoluteQuadsForRange(Vector<FloatQuad>& quads, unsigned start, unsigned end, bool useSelectionHeight, bool* wasFixed)
{
    // Work around signed/unsigned issues. This function takes unsigneds, and is often passed UINT_MAX
    // to mean "all the way to the end". InlineTextBox coordinates are unsigneds, so changing this
    // function to take ints causes various internal mismatches. But selectionRect takes ints, and
    // passing UINT_MAX to it causes trouble. Ideally we'd change selectionRect to take unsigneds, but
    // that would cause many ripple effects, so for now we'll just clamp our unsigned parameters to INT_MAX.
    ASSERT(end == UINT_MAX || end <= INT_MAX);
    ASSERT(start <= INT_MAX);
    start = min(start, static_cast<unsigned>(INT_MAX));
    end = min(end, static_cast<unsigned>(INT_MAX));

    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        // Note: box->end() returns the index of the last character, not the index past it
        if (start <= box->start() && box->end() < end) {
            FloatRect r = box->calculateBoundaries();
            if (useSelectionHeight) {
                LayoutRect selectionRect = box->localSelectionRect(start, end);
                if (box->isHorizontal()) {
                    r.setHeight(selectionRect.height().toFloat());
                    r.setY(selectionRect.y().toFloat());
                } else {
                    r.setWidth(selectionRect.width().toFloat());
                    r.setX(selectionRect.x().toFloat());
                }
            }
            quads.append(localToAbsoluteQuad(r, 0, wasFixed));
        } else {
            FloatRect rect = localQuadForTextBox(box, start, end, useSelectionHeight);
            if (!rect.isZero())
                quads.append(localToAbsoluteQuad(rect, 0, wasFixed));
        }
    }
}

InlineTextBox* RenderText::findNextInlineTextBox(int offset, int& pos) const
{
    // The text runs point to parts of the RenderText's m_text
    // (they don't include '\n')
    // Find the text run that includes the character at offset
    // and return pos, which is the position of the char in the run.

    if (!m_firstTextBox)
        return 0;

    InlineTextBox* s = m_firstTextBox;
    int off = s->len();
    while (offset > off && s->nextTextBox()) {
        s = s->nextTextBox();
        off = s->start() + s->len();
    }
    // we are now in the correct text run
    pos = (offset > off ? s->len() : s->len() - (off - offset) );
    return s;
}

enum ShouldAffinityBeDownstream { AlwaysDownstream, AlwaysUpstream, UpstreamIfPositionIsNotAtStart };

static bool lineDirectionPointFitsInBox(int pointLineDirection, InlineTextBox* box, ShouldAffinityBeDownstream& shouldAffinityBeDownstream)
{
    shouldAffinityBeDownstream = AlwaysDownstream;

    // the x coordinate is equal to the left edge of this box
    // the affinity must be downstream so the position doesn't jump back to the previous line
    // except when box is the first box in the line
    if (pointLineDirection <= box->logicalLeft()) {
        shouldAffinityBeDownstream = !box->prevLeafChild() ? UpstreamIfPositionIsNotAtStart : AlwaysDownstream;
        return true;
    }

    // and the x coordinate is to the left of the right edge of this box
    // check to see if position goes in this box
    if (pointLineDirection < box->logicalRight()) {
        shouldAffinityBeDownstream = UpstreamIfPositionIsNotAtStart;
        return true;
    }

    // box is first on line
    // and the x coordinate is to the left of the first text box left edge
    if (!box->prevLeafChildIgnoringLineBreak() && pointLineDirection < box->logicalLeft())
        return true;

    if (!box->nextLeafChildIgnoringLineBreak()) {
        // box is last on line
        // and the x coordinate is to the right of the last text box right edge
        // generate VisiblePosition, use UPSTREAM affinity if possible
        shouldAffinityBeDownstream = UpstreamIfPositionIsNotAtStart;
        return true;
    }

    return false;
}

static PositionWithAffinity createPositionWithAffinityForBox(const InlineBox* box, int offset, ShouldAffinityBeDownstream shouldAffinityBeDownstream)
{
    EAffinity affinity = VP_DEFAULT_AFFINITY;
    switch (shouldAffinityBeDownstream) {
    case AlwaysDownstream:
        affinity = DOWNSTREAM;
        break;
    case AlwaysUpstream:
        affinity = VP_UPSTREAM_IF_POSSIBLE;
        break;
    case UpstreamIfPositionIsNotAtStart:
        affinity = offset > box->caretMinOffset() ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM;
        break;
    }
    int textStartOffset = box->renderer().isText() ? toRenderText(box->renderer()).textStartOffset() : 0;
    return box->renderer().createPositionWithAffinity(offset + textStartOffset, affinity);
}

static PositionWithAffinity createPositionWithAffinityForBoxAfterAdjustingOffsetForBiDi(const InlineTextBox* box, int offset, ShouldAffinityBeDownstream shouldAffinityBeDownstream)
{
    ASSERT(box);
    ASSERT(offset >= 0);

    if (offset && static_cast<unsigned>(offset) < box->len())
        return createPositionWithAffinityForBox(box, box->start() + offset, shouldAffinityBeDownstream);

    bool positionIsAtStartOfBox = !offset;
    if (positionIsAtStartOfBox == box->isLeftToRightDirection()) {
        // offset is on the left edge

        const InlineBox* prevBox = box->prevLeafChildIgnoringLineBreak();
        if ((prevBox && prevBox->bidiLevel() == box->bidiLevel())
            || box->renderer().containingBlock()->style()->direction() == box->direction()) // FIXME: left on 12CBA
            return createPositionWithAffinityForBox(box, box->caretLeftmostOffset(), shouldAffinityBeDownstream);

        if (prevBox && prevBox->bidiLevel() > box->bidiLevel()) {
            // e.g. left of B in aDC12BAb
            const InlineBox* leftmostBox;
            do {
                leftmostBox = prevBox;
                prevBox = leftmostBox->prevLeafChildIgnoringLineBreak();
            } while (prevBox && prevBox->bidiLevel() > box->bidiLevel());
            return createPositionWithAffinityForBox(leftmostBox, leftmostBox->caretRightmostOffset(), shouldAffinityBeDownstream);
        }

        if (!prevBox || prevBox->bidiLevel() < box->bidiLevel()) {
            // e.g. left of D in aDC12BAb
            const InlineBox* rightmostBox;
            const InlineBox* nextBox = box;
            do {
                rightmostBox = nextBox;
                nextBox = rightmostBox->nextLeafChildIgnoringLineBreak();
            } while (nextBox && nextBox->bidiLevel() >= box->bidiLevel());
            return createPositionWithAffinityForBox(rightmostBox,
                box->isLeftToRightDirection() ? rightmostBox->caretMaxOffset() : rightmostBox->caretMinOffset(), shouldAffinityBeDownstream);
        }

        return createPositionWithAffinityForBox(box, box->caretRightmostOffset(), shouldAffinityBeDownstream);
    }

    const InlineBox* nextBox = box->nextLeafChildIgnoringLineBreak();
    if ((nextBox && nextBox->bidiLevel() == box->bidiLevel())
        || box->renderer().containingBlock()->style()->direction() == box->direction())
        return createPositionWithAffinityForBox(box, box->caretRightmostOffset(), shouldAffinityBeDownstream);

    // offset is on the right edge
    if (nextBox && nextBox->bidiLevel() > box->bidiLevel()) {
        // e.g. right of C in aDC12BAb
        const InlineBox* rightmostBox;
        do {
            rightmostBox = nextBox;
            nextBox = rightmostBox->nextLeafChildIgnoringLineBreak();
        } while (nextBox && nextBox->bidiLevel() > box->bidiLevel());
        return createPositionWithAffinityForBox(rightmostBox, rightmostBox->caretLeftmostOffset(), shouldAffinityBeDownstream);
    }

    if (!nextBox || nextBox->bidiLevel() < box->bidiLevel()) {
        // e.g. right of A in aDC12BAb
        const InlineBox* leftmostBox;
        const InlineBox* prevBox = box;
        do {
            leftmostBox = prevBox;
            prevBox = leftmostBox->prevLeafChildIgnoringLineBreak();
        } while (prevBox && prevBox->bidiLevel() >= box->bidiLevel());
        return createPositionWithAffinityForBox(leftmostBox,
            box->isLeftToRightDirection() ? leftmostBox->caretMinOffset() : leftmostBox->caretMaxOffset(), shouldAffinityBeDownstream);
    }

    return createPositionWithAffinityForBox(box, box->caretLeftmostOffset(), shouldAffinityBeDownstream);
}

PositionWithAffinity RenderText::positionForPoint(const LayoutPoint& point)
{
    if (!firstTextBox() || textLength() == 0)
        return createPositionWithAffinity(0, DOWNSTREAM);

    LayoutUnit pointLineDirection = firstTextBox()->isHorizontal() ? point.x() : point.y();
    LayoutUnit pointBlockDirection = firstTextBox()->isHorizontal() ? point.y() : point.x();
    bool blocksAreFlipped = style()->isFlippedBlocksWritingMode();

    InlineTextBox* lastBox = 0;
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        if (box->isLineBreak() && !box->prevLeafChild() && box->nextLeafChild() && !box->nextLeafChild()->isLineBreak())
            box = box->nextTextBox();

        RootInlineBox& rootBox = box->root();
        LayoutUnit top = min(rootBox.selectionTop(), rootBox.lineTop());
        if (pointBlockDirection > top || (!blocksAreFlipped && pointBlockDirection == top)) {
            LayoutUnit bottom = rootBox.selectionBottom();
            if (rootBox.nextRootBox())
                bottom = min(bottom, rootBox.nextRootBox()->lineTop());

            if (pointBlockDirection < bottom || (blocksAreFlipped && pointBlockDirection == bottom)) {
                ShouldAffinityBeDownstream shouldAffinityBeDownstream;
                if (lineDirectionPointFitsInBox(pointLineDirection, box, shouldAffinityBeDownstream))
                    return createPositionWithAffinityForBoxAfterAdjustingOffsetForBiDi(box, box->offsetForPosition(pointLineDirection.toFloat()), shouldAffinityBeDownstream);
            }
        }
        lastBox = box;
    }

    if (lastBox) {
        ShouldAffinityBeDownstream shouldAffinityBeDownstream;
        lineDirectionPointFitsInBox(pointLineDirection, lastBox, shouldAffinityBeDownstream);
        return createPositionWithAffinityForBoxAfterAdjustingOffsetForBiDi(lastBox, lastBox->offsetForPosition(pointLineDirection.toFloat()) + lastBox->start(), shouldAffinityBeDownstream);
    }
    return createPositionWithAffinity(0, DOWNSTREAM);
}

LayoutRect RenderText::localCaretRect(InlineBox* inlineBox, int caretOffset, LayoutUnit* extraWidthToEndOfLine)
{
    if (!inlineBox)
        return LayoutRect();

    ASSERT(inlineBox->isInlineTextBox());
    if (!inlineBox->isInlineTextBox())
        return LayoutRect();

    InlineTextBox* box = toInlineTextBox(inlineBox);

    int height = box->root().selectionHeight();
    int top = box->root().selectionTop();

    // Go ahead and round left to snap it to the nearest pixel.
    float left = box->positionForOffset(caretOffset);

    // Distribute the caret's width to either side of the offset.
    int caretWidthLeftOfOffset = caretWidth / 2;
    left -= caretWidthLeftOfOffset;
    int caretWidthRightOfOffset = caretWidth - caretWidthLeftOfOffset;

    left = roundf(left);

    float rootLeft = box->root().logicalLeft();
    float rootRight = box->root().logicalRight();

    // FIXME: should we use the width of the root inline box or the
    // width of the containing block for this?
    if (extraWidthToEndOfLine)
        *extraWidthToEndOfLine = (box->root().logicalWidth() + rootLeft) - (left + 1);

    RenderBlock* cb = containingBlock();
    RenderStyle* cbStyle = cb->style();

    float leftEdge;
    float rightEdge;
    leftEdge = min<float>(0, rootLeft);
    rightEdge = max<float>(cb->logicalWidth().toFloat(), rootRight);

    bool rightAligned = false;
    switch (cbStyle->textAlign()) {
    case RIGHT:
    case WEBKIT_RIGHT:
        rightAligned = true;
        break;
    case LEFT:
    case WEBKIT_LEFT:
    case CENTER:
    case WEBKIT_CENTER:
        break;
    case JUSTIFY:
    case TASTART:
        rightAligned = !cbStyle->isLeftToRightDirection();
        break;
    case TAEND:
        rightAligned = cbStyle->isLeftToRightDirection();
        break;
    }

    if (rightAligned) {
        left = max(left, leftEdge);
        left = min(left, rootRight - caretWidth);
    } else {
        left = min(left, rightEdge - caretWidthRightOfOffset);
        left = max(left, rootLeft);
    }

    return style()->isHorizontalWritingMode() ? IntRect(left, top, caretWidth, height) : IntRect(top, left, height, caretWidth);
}

ALWAYS_INLINE float RenderText::widthFromCache(const Font& f, int start, int len, float xPos, TextDirection textDirection, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
{
    if (style()->hasTextCombine() && isCombineText()) {
        const RenderCombineText* combineText = toRenderCombineText(this);
        if (combineText->isCombined())
            return combineText->combinedTextWidth(f);
    }

    if (f.isFixedPitch() && !f.fontDescription().variant() && m_isAllASCII && (!glyphOverflow || !glyphOverflow->computeBounds)) {
        float monospaceCharacterWidth = f.spaceWidth();
        float w = 0;
        bool isSpace;
        ASSERT(m_text);
        StringImpl& text = *m_text.impl();
        for (int i = start; i < start + len; i++) {
            char c = text[i];
            if (c <= ' ') {
                if (c == ' ' || c == '\n') {
                    w += monospaceCharacterWidth;
                    isSpace = true;
                } else if (c == '\t') {
                    if (style()->collapseWhiteSpace()) {
                        w += monospaceCharacterWidth;
                        isSpace = true;
                    } else {
                        w += f.tabWidth(style()->tabSize(), xPos + w);
                        isSpace = false;
                    }
                } else
                    isSpace = false;
            } else {
                w += monospaceCharacterWidth;
                isSpace = false;
            }
            if (isSpace && i > start)
                w += f.fontDescription().wordSpacing();
        }
        return w;
    }

    TextRun run = RenderBlockFlow::constructTextRun(const_cast<RenderText*>(this), f, this, start, len, style(), textDirection);
    run.setCharactersLength(textLength() - start);
    ASSERT(run.charactersLength() >= run.length());

    run.setCharacterScanForCodePath(!canUseSimpleFontCodePath());
    run.setTabSize(!style()->collapseWhiteSpace(), style()->tabSize());
    run.setXPos(xPos);
    return f.width(run, fallbackFonts, glyphOverflow);
}

void RenderText::trimmedPrefWidths(float leadWidth,
    float& firstLineMinWidth, bool& hasBreakableStart,
    float& lastLineMinWidth, bool& hasBreakableEnd,
    bool& hasBreakableChar, bool& hasBreak,
    float& firstLineMaxWidth, float& lastLineMaxWidth,
    float& minWidth, float& maxWidth, bool& stripFrontSpaces,
    TextDirection direction)
{
    bool collapseWhiteSpace = style()->collapseWhiteSpace();
    if (!collapseWhiteSpace)
        stripFrontSpaces = false;

    if (m_hasTab || preferredLogicalWidthsDirty())
        computePreferredLogicalWidths(leadWidth);

    hasBreakableStart = !stripFrontSpaces && m_hasBreakableStart;
    hasBreakableEnd = m_hasBreakableEnd;

    int len = textLength();

    if (!len || (stripFrontSpaces && text().impl()->containsOnlyWhitespace())) {
        firstLineMinWidth = 0;
        lastLineMinWidth = 0;
        firstLineMaxWidth = 0;
        lastLineMaxWidth = 0;
        minWidth = 0;
        maxWidth = 0;
        hasBreak = false;
        return;
    }

    minWidth = m_minWidth;
    maxWidth = m_maxWidth;

    firstLineMinWidth = m_firstLineMinWidth;
    lastLineMinWidth = m_lastLineLineMinWidth;

    hasBreakableChar = m_hasBreakableChar;
    hasBreak = m_hasBreak;

    ASSERT(m_text);
    StringImpl& text = *m_text.impl();
    if (text[0] == ' ' || (text[0] == '\n' && !style()->preserveNewline()) || text[0] == '\t') {
        const Font& font = style()->font(); // FIXME: This ignores first-line.
        if (stripFrontSpaces) {
            const UChar space = ' ';
            float spaceWidth = font.width(RenderBlockFlow::constructTextRun(this, font, &space, 1, style(), direction));
            maxWidth -= spaceWidth;
        } else {
            maxWidth += font.fontDescription().wordSpacing();
        }
    }

    stripFrontSpaces = collapseWhiteSpace && m_hasEndWhiteSpace;

    if (!style()->autoWrap() || minWidth > maxWidth)
        minWidth = maxWidth;

    // Compute our max widths by scanning the string for newlines.
    if (hasBreak) {
        const Font& f = style()->font(); // FIXME: This ignores first-line.
        bool firstLine = true;
        firstLineMaxWidth = maxWidth;
        lastLineMaxWidth = maxWidth;
        for (int i = 0; i < len; i++) {
            int linelen = 0;
            while (i + linelen < len && text[i + linelen] != '\n')
                linelen++;

            if (linelen) {
                lastLineMaxWidth = widthFromCache(f, i, linelen, leadWidth + lastLineMaxWidth, direction, 0, 0);
                if (firstLine) {
                    firstLine = false;
                    leadWidth = 0;
                    firstLineMaxWidth = lastLineMaxWidth;
                }
                i += linelen;
            } else if (firstLine) {
                firstLineMaxWidth = 0;
                firstLine = false;
                leadWidth = 0;
            }

            if (i == len - 1) {
                // A <pre> run that ends with a newline, as in, e.g.,
                // <pre>Some text\n\n<span>More text</pre>
                lastLineMaxWidth = 0;
            }
        }
    }
}

float RenderText::minLogicalWidth() const
{
    if (preferredLogicalWidthsDirty())
        const_cast<RenderText*>(this)->computePreferredLogicalWidths(0);

    return m_minWidth;
}

float RenderText::maxLogicalWidth() const
{
    if (preferredLogicalWidthsDirty())
        const_cast<RenderText*>(this)->computePreferredLogicalWidths(0);

    return m_maxWidth;
}

void RenderText::computePreferredLogicalWidths(float leadWidth)
{
    HashSet<const SimpleFontData*> fallbackFonts;
    GlyphOverflow glyphOverflow;
    computePreferredLogicalWidths(leadWidth, fallbackFonts, glyphOverflow);
    if (fallbackFonts.isEmpty() && !glyphOverflow.left && !glyphOverflow.right && !glyphOverflow.top && !glyphOverflow.bottom)
        m_knownToHaveNoOverflowAndNoFallbackFonts = true;
}

static inline float hyphenWidth(RenderText* renderer, const Font& font, TextDirection direction)
{
    RenderStyle* style = renderer->style();
    return font.width(RenderBlockFlow::constructTextRun(renderer, font, style->hyphenString().string(), style, direction));
}

void RenderText::computePreferredLogicalWidths(float leadWidth, HashSet<const SimpleFontData*>& fallbackFonts, GlyphOverflow& glyphOverflow)
{
    ASSERT(m_hasTab || preferredLogicalWidthsDirty() || !m_knownToHaveNoOverflowAndNoFallbackFonts);

    m_minWidth = 0;
    m_maxWidth = 0;
    m_firstLineMinWidth = 0;
    m_lastLineLineMinWidth = 0;

    if (isBR())
        return;

    float currMinWidth = 0;
    float currMaxWidth = 0;
    m_hasBreakableChar = false;
    m_hasBreak = false;
    m_hasTab = false;
    m_hasBreakableStart = false;
    m_hasBreakableEnd = false;
    m_hasEndWhiteSpace = false;

    RenderStyle* styleToUse = style();
    const Font& f = styleToUse->font(); // FIXME: This ignores first-line.
    float wordSpacing = styleToUse->wordSpacing();
    int len = textLength();
    LazyLineBreakIterator breakIterator(m_text, styleToUse->locale());
    bool needsWordSpacing = false;
    bool ignoringSpaces = false;
    bool isSpace = false;
    bool firstWord = true;
    bool firstLine = true;
    int nextBreakable = -1;
    int lastWordBoundary = 0;
    float cachedWordTrailingSpaceWidth[2] = { 0, 0 }; // LTR, RTL

    int firstGlyphLeftOverflow = -1;

    bool breakAll = (styleToUse->wordBreak() == BreakAllWordBreak || styleToUse->wordBreak() == BreakWordBreak) && styleToUse->autoWrap();

    TextRun textRun(text());
    BidiResolver<TextRunIterator, BidiCharacterRun> bidiResolver;

    BidiCharacterRun* run;
    TextDirection textDirection = styleToUse->direction();
    if (isOverride(styleToUse->unicodeBidi())) {
        run = 0;
    } else {
        BidiStatus status(LTR, false);
        status.last = status.lastStrong = WTF::Unicode::OtherNeutral;
        bidiResolver.setStatus(status);
        bidiResolver.setPositionIgnoringNestedIsolates(TextRunIterator(&textRun, 0));
        bool hardLineBreak = false;
        bool reorderRuns = false;
        bidiResolver.createBidiRunsForLine(TextRunIterator(&textRun, textRun.length()), NoVisualOverride, hardLineBreak, reorderRuns);
        BidiRunList<BidiCharacterRun>& bidiRuns = bidiResolver.runs();
        run = bidiRuns.firstRun();
    }

    for (int i = 0; i < len; i++) {
        UChar c = uncheckedCharacterAt(i);

        if (run) {
            // Treat adjacent runs with the same resolved directionality
            // (TextDirection as opposed to WTF::Unicode::Direction) as belonging
            // to the same run to avoid breaking unnecessarily.
            while (i > run->stop() || (run->next() && run->next()->direction() == run->direction()))
                run = run->next();

            ASSERT(run);
            ASSERT(i <= run->stop());
            textDirection = run->direction();
        }

        bool previousCharacterIsSpace = isSpace;
        bool isNewline = false;
        if (c == '\n') {
            if (styleToUse->preserveNewline()) {
                m_hasBreak = true;
                isNewline = true;
                isSpace = false;
            } else
                isSpace = true;
        } else if (c == '\t') {
            if (!styleToUse->collapseWhiteSpace()) {
                m_hasTab = true;
                isSpace = false;
            } else
                isSpace = true;
        } else
            isSpace = c == ' ';

        bool isBreakableLocation = isNewline || (isSpace && styleToUse->autoWrap());
        if (!i)
            m_hasBreakableStart = isBreakableLocation;
        if (i == len - 1) {
            m_hasBreakableEnd = isBreakableLocation;
            m_hasEndWhiteSpace = isNewline || isSpace;
        }

        if (!ignoringSpaces && styleToUse->collapseWhiteSpace() && previousCharacterIsSpace && isSpace)
            ignoringSpaces = true;

        if (ignoringSpaces && !isSpace)
            ignoringSpaces = false;

        // Ignore spaces and soft hyphens
        if (ignoringSpaces) {
            ASSERT(lastWordBoundary == i);
            lastWordBoundary++;
            continue;
        } else if (c == softHyphen) {
            currMaxWidth += widthFromCache(f, lastWordBoundary, i - lastWordBoundary, leadWidth + currMaxWidth, textDirection, &fallbackFonts, &glyphOverflow);
            if (firstGlyphLeftOverflow < 0)
                firstGlyphLeftOverflow = glyphOverflow.left;
            lastWordBoundary = i + 1;
            continue;
        }

        bool hasBreak = breakAll || isBreakable(breakIterator, i, nextBreakable);
        bool betweenWords = true;
        int j = i;
        while (c != '\n' && c != ' ' && c != '\t' && (c != softHyphen)) {
            j++;
            if (j == len)
                break;
            c = uncheckedCharacterAt(j);
            if (isBreakable(breakIterator, j, nextBreakable) && characterAt(j - 1) != softHyphen)
                break;
            if (breakAll) {
                betweenWords = false;
                break;
            }
        }

        // Terminate word boundary at bidi run boundary.
        if (run)
            j = min(j, run->stop() + 1);
        int wordLen = j - i;
        if (wordLen) {
            bool isSpace = (j < len) && c == ' ';

            // Non-zero only when kerning is enabled, in which case we measure words with their trailing
            // space, then subtract its width.
            float wordTrailingSpaceWidth = 0;
            if (isSpace && (f.fontDescription().typesettingFeatures() & Kerning)) {
                ASSERT(textDirection >=0 && textDirection <= 1);
                if (!cachedWordTrailingSpaceWidth[textDirection])
                    cachedWordTrailingSpaceWidth[textDirection] = f.width(RenderBlockFlow::constructTextRun(this, f, &space, 1, styleToUse, textDirection)) + wordSpacing;
                wordTrailingSpaceWidth = cachedWordTrailingSpaceWidth[textDirection];
            }

            float w;
            if (wordTrailingSpaceWidth && isSpace)
                w = widthFromCache(f, i, wordLen + 1, leadWidth + currMaxWidth, textDirection, &fallbackFonts, &glyphOverflow) - wordTrailingSpaceWidth;
            else {
                w = widthFromCache(f, i, wordLen, leadWidth + currMaxWidth, textDirection, &fallbackFonts, &glyphOverflow);
                if (c == softHyphen)
                    currMinWidth += hyphenWidth(this, f, textDirection);
            }

            if (firstGlyphLeftOverflow < 0)
                firstGlyphLeftOverflow = glyphOverflow.left;
            currMinWidth += w;
            if (betweenWords) {
                if (lastWordBoundary == i)
                    currMaxWidth += w;
                else
                    currMaxWidth += widthFromCache(f, lastWordBoundary, j - lastWordBoundary, leadWidth + currMaxWidth, textDirection, &fallbackFonts, &glyphOverflow);
                lastWordBoundary = j;
            }

            bool isCollapsibleWhiteSpace = (j < len) && styleToUse->isCollapsibleWhiteSpace(c);
            if (j < len && styleToUse->autoWrap())
                m_hasBreakableChar = true;

            // Add in wordSpacing to our currMaxWidth, but not if this is the last word on a line or the
            // last word in the run.
            if (wordSpacing && (isSpace || isCollapsibleWhiteSpace) && !containsOnlyWhitespace(j, len-j))
                currMaxWidth += wordSpacing;

            if (firstWord) {
                firstWord = false;
                // If the first character in the run is breakable, then we consider ourselves to have a beginning
                // minimum width of 0, since a break could occur right before our run starts, preventing us from ever
                // being appended to a previous text run when considering the total minimum width of the containing block.
                if (hasBreak)
                    m_hasBreakableChar = true;
                m_firstLineMinWidth = hasBreak ? 0 : currMinWidth;
            }
            m_lastLineLineMinWidth = currMinWidth;

            if (currMinWidth > m_minWidth)
                m_minWidth = currMinWidth;
            currMinWidth = 0;

            i += wordLen - 1;
        } else {
            // Nowrap can never be broken, so don't bother setting the
            // breakable character boolean. Pre can only be broken if we encounter a newline.
            if (style()->autoWrap() || isNewline)
                m_hasBreakableChar = true;

            if (currMinWidth > m_minWidth)
                m_minWidth = currMinWidth;
            currMinWidth = 0;

            if (isNewline) { // Only set if preserveNewline was true and we saw a newline.
                if (firstLine) {
                    firstLine = false;
                    leadWidth = 0;
                    if (!styleToUse->autoWrap())
                        m_firstLineMinWidth = currMaxWidth;
                }

                if (currMaxWidth > m_maxWidth)
                    m_maxWidth = currMaxWidth;
                currMaxWidth = 0;
            } else {
                TextRun run = RenderBlockFlow::constructTextRun(this, f, this, i, 1, styleToUse, textDirection);
                run.setCharactersLength(len - i);
                ASSERT(run.charactersLength() >= run.length());
                run.setTabSize(!style()->collapseWhiteSpace(), style()->tabSize());
                run.setXPos(leadWidth + currMaxWidth);

                currMaxWidth += f.width(run);
                glyphOverflow.right = 0;
                needsWordSpacing = isSpace && !previousCharacterIsSpace && i == len - 1;
            }
            ASSERT(lastWordBoundary == i);
            lastWordBoundary++;
        }
    }
    if (run)
        bidiResolver.runs().deleteRuns();

    if (firstGlyphLeftOverflow > 0)
        glyphOverflow.left = firstGlyphLeftOverflow;

    if ((needsWordSpacing && len > 1) || (ignoringSpaces && !firstWord))
        currMaxWidth += wordSpacing;

    m_minWidth = max(currMinWidth, m_minWidth);
    m_maxWidth = max(currMaxWidth, m_maxWidth);

    if (!styleToUse->autoWrap())
        m_minWidth = m_maxWidth;

    if (styleToUse->whiteSpace() == PRE) {
        if (firstLine)
            m_firstLineMinWidth = m_maxWidth;
        m_lastLineLineMinWidth = currMaxWidth;
    }

    clearPreferredLogicalWidthsDirty();
}

bool RenderText::isAllCollapsibleWhitespace() const
{
    unsigned length = textLength();
    if (is8Bit()) {
        for (unsigned i = 0; i < length; ++i) {
            if (!style()->isCollapsibleWhiteSpace(characters8()[i]))
                return false;
        }
        return true;
    }
    for (unsigned i = 0; i < length; ++i) {
        if (!style()->isCollapsibleWhiteSpace(characters16()[i]))
            return false;
    }
    return true;
}

bool RenderText::containsOnlyWhitespace(unsigned from, unsigned len) const
{
    ASSERT(m_text);
    StringImpl& text = *m_text.impl();
    unsigned currPos;
    for (currPos = from;
         currPos < from + len && (text[currPos] == '\n' || text[currPos] == ' ' || text[currPos] == '\t');
         currPos++) { }
    return currPos >= (from + len);
}

FloatPoint RenderText::firstRunOrigin() const
{
    return IntPoint(firstRunX(), firstRunY());
}

float RenderText::firstRunX() const
{
    return m_firstTextBox ? m_firstTextBox->x() : 0;
}

float RenderText::firstRunY() const
{
    return m_firstTextBox ? m_firstTextBox->y() : 0;
}

void RenderText::setSelectionState(SelectionState state)
{
    RenderObject::setSelectionState(state);

    if (canUpdateSelectionOnRootLineBoxes()) {
        if (state == SelectionStart || state == SelectionEnd || state == SelectionBoth) {
            int startPos, endPos;
            selectionStartEnd(startPos, endPos);
            if (selectionState() == SelectionStart) {
                endPos = textLength();

                // to handle selection from end of text to end of line
                if (startPos && startPos == endPos)
                    startPos = endPos - 1;
            } else if (selectionState() == SelectionEnd)
                startPos = 0;

            for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
                if (box->isSelected(startPos, endPos)) {
                    box->root().setHasSelectedChildren(true);
                }
            }
        } else {
            for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
                box->root().setHasSelectedChildren(state == SelectionInside);
            }
        }
    }

    // The containing block can be null in case of an orphaned tree.
    RenderBlock* containingBlock = this->containingBlock();
    if (containingBlock && !containingBlock->isRenderView())
        containingBlock->setSelectionState(state);
}

void RenderText::setTextWithOffset(PassRefPtr<StringImpl> text, unsigned offset, unsigned len, bool force)
{
    if (!force && equal(m_text.impl(), text.get()))
        return;

    unsigned oldLen = textLength();
    unsigned newLen = text->length();
    int delta = newLen - oldLen;
    unsigned end = len ? offset + len - 1 : offset;

    RootInlineBox* firstRootBox = 0;
    RootInlineBox* lastRootBox = 0;

    bool dirtiedLines = false;

    // Dirty all text boxes that include characters in between offset and offset+len.
    for (InlineTextBox* curr = firstTextBox(); curr; curr = curr->nextTextBox()) {
        // FIXME: This shouldn't rely on the end of a dirty line box. See https://bugs.webkit.org/show_bug.cgi?id=97264
        // Text run is entirely before the affected range.
        if (curr->end() < offset)
            continue;

        // Text run is entirely after the affected range.
        if (curr->start() > end) {
            curr->offsetRun(delta);
            RootInlineBox* root = &curr->root();
            if (!firstRootBox) {
                firstRootBox = root;
                // The affected area was in between two runs. Go ahead and mark the root box of
                // the run after the affected area as dirty.
                firstRootBox->markDirty();
                dirtiedLines = true;
            }
            lastRootBox = root;
        } else if (curr->end() >= offset && curr->end() <= end) {
            // Text run overlaps with the left end of the affected range.
            curr->dirtyLineBoxes();
            dirtiedLines = true;
        } else if (curr->start() <= offset && curr->end() >= end) {
            // Text run subsumes the affected range.
            curr->dirtyLineBoxes();
            dirtiedLines = true;
        } else if (curr->start() <= end && curr->end() >= end) {
            // Text run overlaps with right end of the affected range.
            curr->dirtyLineBoxes();
            dirtiedLines = true;
        }
    }

    // Now we have to walk all of the clean lines and adjust their cached line break information
    // to reflect our updated offsets.
    if (lastRootBox)
        lastRootBox = lastRootBox->nextRootBox();
    if (firstRootBox) {
        RootInlineBox* prev = firstRootBox->prevRootBox();
        if (prev)
            firstRootBox = prev;
    } else if (lastTextBox()) {
        ASSERT(!lastRootBox);
        firstRootBox = &lastTextBox()->root();
        firstRootBox->markDirty();
        dirtiedLines = true;
    }
    for (RootInlineBox* curr = firstRootBox; curr && curr != lastRootBox; curr = curr->nextRootBox()) {
        if (curr->lineBreakObj() == this && curr->lineBreakPos() > end)
            curr->setLineBreakPos(clampToInteger(curr->lineBreakPos() + delta));
    }

    // If the text node is empty, dirty the line where new text will be inserted.
    if (!firstTextBox() && parent()) {
        parent()->dirtyLinesFromChangedChild(this);
        dirtiedLines = true;
    }

    m_linesDirty = dirtiedLines;
    setText(text, force || dirtiedLines);
}

void RenderText::transformText()
{
    if (RefPtr<StringImpl> textToTransform = originalText())
        setText(textToTransform.release(), true);
}

static inline bool isInlineFlowOrEmptyText(const RenderObject* o)
{
    if (o->isRenderInline())
        return true;
    if (!o->isText())
        return false;
    return toRenderText(o)->text().isEmpty();
}

UChar RenderText::previousCharacter() const
{
    // find previous text renderer if one exists
    const RenderObject* previousText = this;
    while ((previousText = previousText->previousInPreOrder()))
        if (!isInlineFlowOrEmptyText(previousText))
            break;
    UChar prev = ' ';
    if (previousText && previousText->isText())
        if (StringImpl* previousString = toRenderText(previousText)->text().impl())
            prev = (*previousString)[previousString->length() - 1];
    return prev;
}

void RenderText::addLayerHitTestRects(LayerHitTestRects&, const RenderLayer* currentLayer, const LayoutPoint& layerOffset, const LayoutRect& containerRect) const
{
    // Text nodes aren't event targets, so don't descend any further.
}

void applyTextTransform(const RenderStyle* style, String& text, UChar previousCharacter)
{
    if (!style)
        return;

    switch (style->textTransform()) {
    case TTNONE:
        break;
    case CAPITALIZE:
        makeCapitalized(&text, previousCharacter);
        break;
    case UPPERCASE:
        text = text.upper(style->locale());
        break;
    case LOWERCASE:
        text = text.lower(style->locale());
        break;
    }
}

void RenderText::setTextInternal(PassRefPtr<StringImpl> text)
{
    ASSERT(text);
    m_text = text;

    if (style()) {
        applyTextTransform(style(), m_text, previousCharacter());

        // We use the same characters here as for list markers.
        // See the listMarkerText function in RenderListMarker.cpp.
        switch (style()->textSecurity()) {
        case TSNONE:
            break;
        case TSCIRCLE:
            secureText(whiteBullet);
            break;
        case TSDISC:
            secureText(bullet);
            break;
        case TSSQUARE:
            secureText(blackSquare);
        }
    }

    ASSERT(m_text);
    ASSERT(!isBR() || (textLength() == 1 && m_text[0] == '\n'));

    m_isAllASCII = m_text.containsOnlyASCII();
    m_canUseSimpleFontCodePath = computeCanUseSimpleFontCodePath();
}

void RenderText::secureText(UChar mask)
{
    if (!m_text.length())
        return;

    int lastTypedCharacterOffsetToReveal = -1;
    UChar revealedText;
    SecureTextTimer* secureTextTimer = gSecureTextTimers ? gSecureTextTimers->get(this) : 0;
    if (secureTextTimer && secureTextTimer->isActive()) {
        lastTypedCharacterOffsetToReveal = secureTextTimer->lastTypedCharacterOffset();
        if (lastTypedCharacterOffsetToReveal >= 0)
            revealedText = m_text[lastTypedCharacterOffsetToReveal];
    }

    m_text.fill(mask);
    if (lastTypedCharacterOffsetToReveal >= 0) {
        m_text.replace(lastTypedCharacterOffsetToReveal, 1, String(&revealedText, 1));
        // m_text may be updated later before timer fires. We invalidate the lastTypedCharacterOffset to avoid inconsistency.
        secureTextTimer->invalidate();
    }
}

void RenderText::setText(PassRefPtr<StringImpl> text, bool force)
{
    ASSERT(text);

    if (!force && equal(m_text.impl(), text.get()))
        return;

    setTextInternal(text);
    // If preferredLogicalWidthsDirty() of an orphan child is true, RenderObjectChildList::
    // insertChildNode() fails to set true to owner. To avoid that, we call
    // setNeedsLayoutAndPrefWidthsRecalc() only if this RenderText has parent.
    if (parent())
        setNeedsLayoutAndPrefWidthsRecalc();
    m_knownToHaveNoOverflowAndNoFallbackFonts = false;

    if (AXObjectCache* cache = document().existingAXObjectCache())
        cache->textChanged(this);
}

void RenderText::dirtyLineBoxes(bool fullLayout)
{
    if (fullLayout)
        deleteTextBoxes();
    else if (!m_linesDirty) {
        for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
            box->dirtyLineBoxes();
    }
    m_linesDirty = false;
}

InlineTextBox* RenderText::createTextBox()
{
    return new InlineTextBox(*this);
}

InlineTextBox* RenderText::createInlineTextBox()
{
    InlineTextBox* textBox = createTextBox();
    if (!m_firstTextBox)
        m_firstTextBox = m_lastTextBox = textBox;
    else {
        m_lastTextBox->setNextTextBox(textBox);
        textBox->setPreviousTextBox(m_lastTextBox);
        m_lastTextBox = textBox;
    }
    textBox->setIsText(true);
    return textBox;
}

void RenderText::positionLineBox(InlineBox* box)
{
    InlineTextBox* s = toInlineTextBox(box);

    // FIXME: should not be needed!!!
    if (!s->len()) {
        // We want the box to be destroyed.
        s->remove();
        if (m_firstTextBox == s)
            m_firstTextBox = s->nextTextBox();
        else
            s->prevTextBox()->setNextTextBox(s->nextTextBox());
        if (m_lastTextBox == s)
            m_lastTextBox = s->prevTextBox();
        else
            s->nextTextBox()->setPreviousTextBox(s->prevTextBox());
        s->destroy();
        return;
    }

    m_containsReversedText |= !s->isLeftToRightDirection();
}

float RenderText::width(unsigned from, unsigned len, float xPos, TextDirection textDirection, bool firstLine, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
{
    if (from >= textLength())
        return 0;

    if (from + len > textLength())
        len = textLength() - from;

    return width(from, len, style(firstLine)->font(), xPos, textDirection, fallbackFonts, glyphOverflow);
}

float RenderText::width(unsigned from, unsigned len, const Font& f, float xPos, TextDirection textDirection, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
{
    ASSERT(from + len <= textLength());
    if (!textLength())
        return 0;

    float w;
    if (&f == &style()->font()) {
        if (!style()->preserveNewline() && !from && len == textLength() && (!glyphOverflow || !glyphOverflow->computeBounds)) {
            if (fallbackFonts) {
                ASSERT(glyphOverflow);
                if (preferredLogicalWidthsDirty() || !m_knownToHaveNoOverflowAndNoFallbackFonts) {
                    const_cast<RenderText*>(this)->computePreferredLogicalWidths(0, *fallbackFonts, *glyphOverflow);
                    if (fallbackFonts->isEmpty() && !glyphOverflow->left && !glyphOverflow->right && !glyphOverflow->top && !glyphOverflow->bottom)
                        m_knownToHaveNoOverflowAndNoFallbackFonts = true;
                }
                w = m_maxWidth;
            } else {
                w = maxLogicalWidth();
            }
        } else {
            w = widthFromCache(f, from, len, xPos, textDirection, fallbackFonts, glyphOverflow);
        }
    } else {
        TextRun run = RenderBlockFlow::constructTextRun(const_cast<RenderText*>(this), f, this, from, len, style(), textDirection);
        run.setCharactersLength(textLength() - from);
        ASSERT(run.charactersLength() >= run.length());

        run.setCharacterScanForCodePath(!canUseSimpleFontCodePath());
        run.setTabSize(!style()->collapseWhiteSpace(), style()->tabSize());
        run.setXPos(xPos);
        w = f.width(run, fallbackFonts, glyphOverflow);
    }

    return w;
}

IntRect RenderText::linesBoundingBox() const
{
    IntRect result;

    ASSERT(!firstTextBox() == !lastTextBox());  // Either both are null or both exist.
    if (firstTextBox() && lastTextBox()) {
        // Return the width of the minimal left side and the maximal right side.
        float logicalLeftSide = 0;
        float logicalRightSide = 0;
        for (InlineTextBox* curr = firstTextBox(); curr; curr = curr->nextTextBox()) {
            if (curr == firstTextBox() || curr->logicalLeft() < logicalLeftSide)
                logicalLeftSide = curr->logicalLeft();
            if (curr == firstTextBox() || curr->logicalRight() > logicalRightSide)
                logicalRightSide = curr->logicalRight();
        }

        bool isHorizontal = style()->isHorizontalWritingMode();

        float x = isHorizontal ? logicalLeftSide : firstTextBox()->x();
        float y = isHorizontal ? firstTextBox()->y() : logicalLeftSide;
        float width = isHorizontal ? logicalRightSide - logicalLeftSide : lastTextBox()->logicalBottom() - x;
        float height = isHorizontal ? lastTextBox()->logicalBottom() - y : logicalRightSide - logicalLeftSide;
        result = enclosingIntRect(FloatRect(x, y, width, height));
    }

    return result;
}

LayoutRect RenderText::linesVisualOverflowBoundingBox() const
{
    if (!firstTextBox())
        return LayoutRect();

    // Return the width of the minimal left side and the maximal right side.
    LayoutUnit logicalLeftSide = LayoutUnit::max();
    LayoutUnit logicalRightSide = LayoutUnit::min();
    for (InlineTextBox* curr = firstTextBox(); curr; curr = curr->nextTextBox()) {
        logicalLeftSide = min(logicalLeftSide, curr->logicalLeftVisualOverflow());
        logicalRightSide = max(logicalRightSide, curr->logicalRightVisualOverflow());
    }

    LayoutUnit logicalTop = firstTextBox()->logicalTopVisualOverflow();
    LayoutUnit logicalWidth = logicalRightSide - logicalLeftSide;
    LayoutUnit logicalHeight = lastTextBox()->logicalBottomVisualOverflow() - logicalTop;

    LayoutRect rect(logicalLeftSide, logicalTop, logicalWidth, logicalHeight);
    if (!style()->isHorizontalWritingMode())
        rect = rect.transposedRect();
    return rect;
}

LayoutRect RenderText::clippedOverflowRectForRepaint(const RenderLayerModelObject* repaintContainer) const
{
    RenderObject* rendererToRepaint = containingBlock();

    // Do not cross self-painting layer boundaries.
    RenderObject* enclosingLayerRenderer = enclosingLayer()->renderer();
    if (enclosingLayerRenderer != rendererToRepaint && !rendererToRepaint->isDescendantOf(enclosingLayerRenderer))
        rendererToRepaint = enclosingLayerRenderer;

    // The renderer we chose to repaint may be an ancestor of repaintContainer, but we need to do a repaintContainer-relative repaint.
    if (repaintContainer && repaintContainer != rendererToRepaint && !rendererToRepaint->isDescendantOf(repaintContainer))
        return repaintContainer->clippedOverflowRectForRepaint(repaintContainer);

    return rendererToRepaint->clippedOverflowRectForRepaint(repaintContainer);
}

LayoutRect RenderText::selectionRectForRepaint(const RenderLayerModelObject* repaintContainer, bool clipToVisibleContent)
{
    ASSERT(!needsLayout());

    if (selectionState() == SelectionNone)
        return LayoutRect();
    RenderBlock* cb = containingBlock();
    if (!cb)
        return LayoutRect();

    // Now calculate startPos and endPos for painting selection.
    // We include a selection while endPos > 0
    int startPos, endPos;
    if (selectionState() == SelectionInside) {
        // We are fully selected.
        startPos = 0;
        endPos = textLength();
    } else {
        selectionStartEnd(startPos, endPos);
        if (selectionState() == SelectionStart)
            endPos = textLength();
        else if (selectionState() == SelectionEnd)
            startPos = 0;
    }

    if (startPos == endPos)
        return IntRect();

    LayoutRect rect;
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        rect.unite(box->localSelectionRect(startPos, endPos));
        rect.unite(ellipsisRectForBox(box, startPos, endPos));
    }

    if (clipToVisibleContent)
        computeRectForRepaint(repaintContainer, rect);
    else {
        if (cb->hasColumns())
            cb->adjustRectForColumns(rect);

        rect = localToContainerQuad(FloatRect(rect), repaintContainer).enclosingBoundingBox();
    }

    return rect;
}

int RenderText::caretMinOffset() const
{
    InlineTextBox* box = firstTextBox();
    if (!box)
        return 0;
    int minOffset = box->start();
    for (box = box->nextTextBox(); box; box = box->nextTextBox())
        minOffset = min<int>(minOffset, box->start());
    return minOffset;
}

int RenderText::caretMaxOffset() const
{
    InlineTextBox* box = lastTextBox();
    if (!lastTextBox())
        return textLength();

    int maxOffset = box->start() + box->len();
    for (box = box->prevTextBox(); box; box = box->prevTextBox())
        maxOffset = max<int>(maxOffset, box->start() + box->len());
    return maxOffset;
}

unsigned RenderText::renderedTextLength() const
{
    int l = 0;
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
        l += box->len();
    return l;
}

int RenderText::previousOffset(int current) const
{
    if (isAllASCII() || m_text.is8Bit())
        return current - 1;

    StringImpl* textImpl = m_text.impl();
    TextBreakIterator* iterator = cursorMovementIterator(textImpl->characters16(), textImpl->length());
    if (!iterator)
        return current - 1;

    long result = iterator->preceding(current);
    if (result == TextBreakDone)
        result = current - 1;


    return result;
}

#if OS(POSIX)

#define HANGUL_CHOSEONG_START (0x1100)
#define HANGUL_CHOSEONG_END (0x115F)
#define HANGUL_JUNGSEONG_START (0x1160)
#define HANGUL_JUNGSEONG_END (0x11A2)
#define HANGUL_JONGSEONG_START (0x11A8)
#define HANGUL_JONGSEONG_END (0x11F9)
#define HANGUL_SYLLABLE_START (0xAC00)
#define HANGUL_SYLLABLE_END (0xD7AF)
#define HANGUL_JONGSEONG_COUNT (28)

enum HangulState {
    HangulStateL,
    HangulStateV,
    HangulStateT,
    HangulStateLV,
    HangulStateLVT,
    HangulStateBreak
};

inline bool isHangulLVT(UChar32 character)
{
    return (character - HANGUL_SYLLABLE_START) % HANGUL_JONGSEONG_COUNT;
}

inline bool isMark(UChar32 c)
{
    int8_t charType = u_charType(c);
    return charType == U_NON_SPACING_MARK || charType == U_ENCLOSING_MARK || charType == U_COMBINING_SPACING_MARK;
}

inline bool isRegionalIndicator(UChar32 c)
{
    // National flag emoji each consists of a pair of regional indicator symbols.
    return 0x1F1E6 <= c && c <= 0x1F1FF;
}

#endif

int RenderText::previousOffsetForBackwardDeletion(int current) const
{
#if OS(POSIX)
    ASSERT(m_text);
    StringImpl& text = *m_text.impl();
    UChar32 character;
    bool sawRegionalIndicator = false;
    while (current > 0) {
        if (U16_IS_TRAIL(text[--current]))
            --current;
        if (current < 0)
            break;

        UChar32 character = text.characterStartingAt(current);

        if (sawRegionalIndicator) {
            // We don't check if the pair of regional indicator symbols before current position can actually be combined
            // into a flag, and just delete it. This may not agree with how the pair is rendered in edge cases,
            // but is good enough in practice.
            if (isRegionalIndicator(character))
                break;
            // Don't delete a preceding character that isn't a regional indicator symbol.
            U16_FWD_1_UNSAFE(text, current);
        }

        // We don't combine characters in Armenian ... Limbu range for backward deletion.
        if ((character >= 0x0530) && (character < 0x1950))
            break;

        if (isRegionalIndicator(character)) {
            sawRegionalIndicator = true;
            continue;
        }

        if (!isMark(character) && (character != 0xFF9E) && (character != 0xFF9F))
            break;
    }

    if (current <= 0)
        return current;

    // Hangul
    character = text.characterStartingAt(current);
    if (((character >= HANGUL_CHOSEONG_START) && (character <= HANGUL_JONGSEONG_END)) || ((character >= HANGUL_SYLLABLE_START) && (character <= HANGUL_SYLLABLE_END))) {
        HangulState state;

        if (character < HANGUL_JUNGSEONG_START)
            state = HangulStateL;
        else if (character < HANGUL_JONGSEONG_START)
            state = HangulStateV;
        else if (character < HANGUL_SYLLABLE_START)
            state = HangulStateT;
        else
            state = isHangulLVT(character) ? HangulStateLVT : HangulStateLV;

        while (current > 0 && ((character = text.characterStartingAt(current - 1)) >= HANGUL_CHOSEONG_START) && (character <= HANGUL_SYLLABLE_END) && ((character <= HANGUL_JONGSEONG_END) || (character >= HANGUL_SYLLABLE_START))) {
            switch (state) {
            case HangulStateV:
                if (character <= HANGUL_CHOSEONG_END)
                    state = HangulStateL;
                else if ((character >= HANGUL_SYLLABLE_START) && (character <= HANGUL_SYLLABLE_END) && !isHangulLVT(character))
                    state = HangulStateLV;
                else if (character > HANGUL_JUNGSEONG_END)
                    state = HangulStateBreak;
                break;
            case HangulStateT:
                if ((character >= HANGUL_JUNGSEONG_START) && (character <= HANGUL_JUNGSEONG_END))
                    state = HangulStateV;
                else if ((character >= HANGUL_SYLLABLE_START) && (character <= HANGUL_SYLLABLE_END))
                    state = (isHangulLVT(character) ? HangulStateLVT : HangulStateLV);
                else if (character < HANGUL_JUNGSEONG_START)
                    state = HangulStateBreak;
                break;
            default:
                state = (character < HANGUL_JUNGSEONG_START) ? HangulStateL : HangulStateBreak;
                break;
            }
            if (state == HangulStateBreak)
                break;

            --current;
        }
    }

    return current;
#else
    // Platforms other than Unix-like delete by one code point.
    if (U16_IS_TRAIL(m_text[--current]))
        --current;
    if (current < 0)
        current = 0;
    return current;
#endif
}

int RenderText::nextOffset(int current) const
{
    if (isAllASCII() || m_text.is8Bit())
        return current + 1;

    StringImpl* textImpl = m_text.impl();
    TextBreakIterator* iterator = cursorMovementIterator(textImpl->characters16(), textImpl->length());
    if (!iterator)
        return current + 1;

    long result = iterator->following(current);
    if (result == TextBreakDone)
        result = current + 1;

    return result;
}

bool RenderText::computeCanUseSimpleFontCodePath() const
{
    if (isAllASCII() || m_text.is8Bit())
        return true;
    return Character::characterRangeCodePath(characters16(), length()) == SimplePath;
}

#ifndef NDEBUG

void RenderText::checkConsistency() const
{
#ifdef CHECK_CONSISTENCY
    const InlineTextBox* prev = 0;
    for (const InlineTextBox* child = m_firstTextBox; child != 0; child = child->nextTextBox()) {
        ASSERT(child->renderer() == this);
        ASSERT(child->prevTextBox() == prev);
        prev = child;
    }
    ASSERT(prev == m_lastTextBox);
#endif
}

#endif

void RenderText::momentarilyRevealLastTypedCharacter(unsigned lastTypedCharacterOffset)
{
    if (!gSecureTextTimers)
        gSecureTextTimers = new SecureTextTimerMap;

    SecureTextTimer* secureTextTimer = gSecureTextTimers->get(this);
    if (!secureTextTimer) {
        secureTextTimer = new SecureTextTimer(this);
        gSecureTextTimers->add(this, secureTextTimer);
    }
    secureTextTimer->restartWithNewText(lastTypedCharacterOffset);
}

PassRefPtr<AbstractInlineTextBox> RenderText::firstAbstractInlineTextBox()
{
    return AbstractInlineTextBox::getOrCreate(this, m_firstTextBox);
}

} // namespace WebCore
/* [<][>][^][v][top][bottom][index][help] */
root/Source/core/rendering/RenderText.cpp

DEFINITIONS
