From cad810f21b803229eb11403f9209855525a25d57 Mon Sep 17 00:00:00 2001 From: Steve Block Date: Fri, 6 May 2011 11:45:16 +0100 Subject: Merge WebKit at r75315: Initial merge by git. Change-Id: I570314b346ce101c935ed22a626b48c2af266b84 --- Source/WebCore/rendering/RenderText.cpp | 1539 +++++++++++++++++++++++++++++++ 1 file changed, 1539 insertions(+) create mode 100644 Source/WebCore/rendering/RenderText.cpp (limited to 'Source/WebCore/rendering/RenderText.cpp') diff --git a/Source/WebCore/rendering/RenderText.cpp b/Source/WebCore/rendering/RenderText.cpp new file mode 100644 index 0000000..78c5684 --- /dev/null +++ b/Source/WebCore/rendering/RenderText.cpp @@ -0,0 +1,1539 @@ +/* + * (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 "RenderText.h" + +#include "AXObjectCache.h" +#include "CharacterNames.h" +#include "EllipsisBox.h" +#include "FloatQuad.h" +#include "FontTranscoder.h" +#include "FrameView.h" +#include "InlineTextBox.h" +#include "Range.h" +#include "RenderArena.h" +#include "RenderBlock.h" +#include "RenderLayer.h" +#include "RenderView.h" +#include "Text.h" +#include "TextBreakIterator.h" +#include "TextResourceDecoder.h" +#include "VisiblePosition.h" +#include "break_lines.h" +#include +#include + +using namespace std; +using namespace WTF; +using namespace Unicode; + +namespace WebCore { + +static void makeCapitalized(String* string, UChar previous) +{ + if (string->isNull()) + return; + + unsigned length = string->length(); + const UChar* characters = string->characters(); + + if (length >= numeric_limits::max()) + CRASH(); + + StringBuffer stringWithPrevious(length + 1); + stringWithPrevious[0] = previous == noBreakSpace ? ' ' : previous; + for (unsigned i = 1; i < length + 1; i++) { + // Replace   with a real space since ICU no longer treats   as a word separator. + if (characters[i - 1] == noBreakSpace) + stringWithPrevious[i] = ' '; + else + stringWithPrevious[i] = characters[i - 1]; + } + + TextBreakIterator* boundary = wordBreakIterator(stringWithPrevious.characters(), length + 1); + if (!boundary) + return; + + StringBuffer data(length); + + int32_t endOfWord; + int32_t startOfWord = textBreakFirst(boundary); + for (endOfWord = textBreakNext(boundary); endOfWord != TextBreakDone; startOfWord = endOfWord, endOfWord = textBreakNext(boundary)) { + if (startOfWord != 0) // Ignore first char of previous string + data[startOfWord - 1] = characters[startOfWord - 1] == noBreakSpace ? noBreakSpace : toTitleCase(stringWithPrevious[startOfWord]); + for (int i = startOfWord + 1; i < endOfWord; i++) + data[i - 1] = characters[i - 1]; + } + + *string = String::adopt(data); +} + +RenderText::RenderText(Node* node, PassRefPtr str) + : RenderObject(node) + , m_minWidth(-1) + , m_text(str) + , m_firstTextBox(0) + , m_lastTextBox(0) + , m_maxWidth(-1) + , m_beginMinWidth(0) + , m_endMinWidth(0) + , m_hasTab(false) + , m_linesDirty(false) + , m_containsReversedText(false) + , m_isAllASCII(m_text.containsOnlyASCII()) + , m_knownToHaveNoOverflowAndNoFallbackFonts(false) + , m_needsTranscoding(false) +{ + ASSERT(m_text); + + setIsText(); + + // FIXME: It would be better to call this only if !m_text->containsOnlyWhitespace(). + // But that might slow things down, and maybe should only be done if visuallyNonEmpty + // is still false. Not making any change for now, but should consider in the future. + view()->frameView()->setIsVisuallyNonEmpty(); +} + +#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::updateNeedsTranscoding() +{ + const TextEncoding* encoding = document()->decoder() ? &document()->decoder()->encoding() : 0; + m_needsTranscoding = fontTranscoder().needsTranscoding(style()->font().fontDescription(), encoding); +} + +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; + } + + bool needsResetText = false; + if (!oldStyle) { + updateNeedsTranscoding(); + needsResetText = m_needsTranscoding; + } else if (oldStyle->font().needsTranscoding() != style()->font().needsTranscoding() || (style()->font().needsTranscoding() && oldStyle->font().family().family() != style()->font().family().family())) { + updateNeedsTranscoding(); + needsResetText = true; + } + + ETextTransform oldTransform = oldStyle ? oldStyle->textTransform() : TTNONE; + ETextSecurity oldSecurity = oldStyle ? oldStyle->textSecurity() : TSNONE; + if (needsResetText || oldTransform != style()->textTransform() || oldSecurity != style()->textSecurity()) { + if (RefPtr textToTransform = originalText()) + setText(textToTransform.release(), true); + } +} + +void RenderText::destroy() +{ + 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(); + RenderObject::destroy(); +} + +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()) { + RenderArena* arena = renderArena(); + InlineTextBox* next; + for (InlineTextBox* curr = firstTextBox(); curr; curr = next) { + next = curr->nextTextBox(); + curr->destroy(arena); + } + m_firstTextBox = m_lastTextBox = 0; + } +} + +PassRefPtr RenderText::originalText() const +{ + Node* e = node(); + return (e && e->isTextNode()) ? static_cast(e)->dataImpl() : 0; +} + +void RenderText::absoluteRects(Vector& rects, int tx, int ty) +{ + for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) + rects.append(IntRect(tx + box->x(), ty + box->y(), box->logicalWidth(), box->logicalHeight())); +} + +void RenderText::absoluteRectsForRange(Vector& rects, unsigned start, unsigned end, bool useSelectionHeight) +{ + // 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(INT_MAX)); + end = min(end, static_cast(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) { + IntRect r = IntRect(box->x(), box->y(), box->logicalWidth(), box->logicalHeight()); + if (useSelectionHeight) { + IntRect selectionRect = box->selectionRect(0, 0, start, end); + r.setHeight(selectionRect.height()); + r.setY(selectionRect.y()); + } + FloatPoint origin = localToAbsolute(r.location()); + r.setX(origin.x()); + r.setY(origin.y()); + rects.append(r); + } else { + unsigned realEnd = min(box->end() + 1, end); + IntRect r = box->selectionRect(0, 0, start, realEnd); + if (!r.isEmpty()) { + if (!useSelectionHeight) { + // change the height and y position because selectionRect uses selection-specific values + r.setHeight(box->logicalHeight()); + r.setY(box->y()); + } + FloatPoint origin = localToAbsolute(r.location()); + localToAbsolute(origin); + r.setX(origin.x()); + r.setY(origin.y()); + rects.append(r); + } + } + } +} + +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(startPos - box->start(), 0); + int ellipsisEndPosition = min(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(0, 0); + } + + return IntRect(); +} + +void RenderText::absoluteQuads(Vector& quads, ClippingOption option) +{ + for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) { + IntRect boundaries = box->calculateBoundaries(); + + // Shorten the width of this text box if it ends in an ellipsis. + IntRect ellipsisRect = (option == ClipToEllipsis) ? ellipsisRectForBox(box, 0, textLength()) : IntRect(); + if (!ellipsisRect.isEmpty()) + boundaries.setWidth(ellipsisRect.right() - boundaries.x()); + quads.append(localToAbsoluteQuad(FloatRect(boundaries))); + } +} + +void RenderText::absoluteQuads(Vector& quads) +{ + absoluteQuads(quads, NoClipping); +} + +void RenderText::absoluteQuadsForRange(Vector& quads, unsigned start, unsigned end, bool useSelectionHeight) +{ + // 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(INT_MAX)); + end = min(end, static_cast(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) { + IntRect r(box->calculateBoundaries()); + if (useSelectionHeight) { + IntRect selectionRect = box->selectionRect(0, 0, start, end); + r.setHeight(selectionRect.height()); + r.setY(selectionRect.y()); + } + quads.append(localToAbsoluteQuad(FloatRect(r))); + } else { + unsigned realEnd = min(box->end() + 1, end); + IntRect r = box->selectionRect(0, 0, start, realEnd); + if (r.height()) { + if (!useSelectionHeight) { + // change the height and y position because selectionRect uses selection-specific values + r.setHeight(box->logicalHeight()); + r.setY(box->y()); + } + quads.append(localToAbsoluteQuad(FloatRect(r))); + } + } + } +} + +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; +} + +VisiblePosition RenderText::positionForPoint(const IntPoint& point) +{ + if (!firstTextBox() || textLength() == 0) + return createVisiblePosition(0, DOWNSTREAM); + + // Get the offset for the position, since this will take rtl text into account. + int offset; + + int pointLineDirection = firstTextBox()->isHorizontal() ? point.x() : point.y(); + int pointBlockDirection = firstTextBox()->isHorizontal() ? point.y() : point.x(); + + // FIXME: We should be able to roll these special cases into the general cases in the loop below. + if (firstTextBox() && pointBlockDirection < firstTextBox()->root()->selectionBottom() && pointLineDirection < firstTextBox()->logicalLeft()) { + // at the y coordinate of the first line or above + // and the x coordinate is to the left of the first text box left edge + offset = firstTextBox()->offsetForPosition(pointLineDirection); + return createVisiblePosition(offset + firstTextBox()->start(), offset > 0 ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM); + } + if (lastTextBox() && pointBlockDirection >= lastTextBox()->root()->selectionTop() && pointLineDirection >= lastTextBox()->logicalRight()) { + // at the y coordinate of the last line or below + // and the x coordinate is to the right of the last text box right edge + offset = lastTextBox()->offsetForPosition(pointLineDirection); + return createVisiblePosition(offset + lastTextBox()->start(), VP_UPSTREAM_IF_POSSIBLE); + } + + InlineTextBox* lastBoxAbove = 0; + for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) { + RootInlineBox* rootBox = box->root(); + if (pointBlockDirection >= rootBox->selectionTop()) { + int bottom = rootBox->selectionBottom(); + if (rootBox->nextRootBox()) + bottom = min(bottom, rootBox->nextRootBox()->lineTop()); + if (pointBlockDirection < bottom) { + offset = box->offsetForPosition(pointLineDirection); + + if (pointLineDirection == box->logicalLeft()) + // 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 + return createVisiblePosition(offset + box->start(), DOWNSTREAM); + + if (pointLineDirection < box->logicalRight()) + // and the x coordinate is to the left of the right edge of this box + // check to see if position goes in this box + return createVisiblePosition(offset + box->start(), offset > 0 ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM); + + if (!box->prevOnLine() && pointLineDirection < box->logicalLeft()) + // box is first on line + // and the x coordinate is to the left of the first text box left edge + return createVisiblePosition(offset + box->start(), DOWNSTREAM); + + if (!box->nextOnLine()) + // 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 + return createVisiblePosition(offset + box->start(), offset > 0 ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM); + } + lastBoxAbove = box; + } + } + + return createVisiblePosition(lastBoxAbove ? lastBoxAbove->start() + lastBoxAbove->len() : 0, DOWNSTREAM); +} + +IntRect RenderText::localCaretRect(InlineBox* inlineBox, int caretOffset, int* extraWidthToEndOfLine) +{ + if (!inlineBox) + return IntRect(); + + ASSERT(inlineBox->isInlineTextBox()); + if (!inlineBox->isInlineTextBox()) + return IntRect(); + + InlineTextBox* box = static_cast(inlineBox); + + int height = box->root()->selectionHeight(); + int top = box->root()->selectionTop(); + + int 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; + + int rootLeft = box->root()->logicalLeft(); + int rootRight = rootLeft + box->root()->logicalWidth(); + // 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(); + int leftEdge; + int rightEdge; + if (style()->autoWrap()) { + leftEdge = cb->logicalLeft(); + rightEdge = cb->logicalRight(); + } else { + leftEdge = min(cb->logicalLeft(), rootLeft); + rightEdge = max(cb->logicalRight(), rootRight); + } + + bool rightAligned = false; + switch (cbStyle->textAlign()) { + case TAAUTO: + case JUSTIFY: + rightAligned = !cbStyle->isLeftToRightDirection(); + break; + case RIGHT: + case WEBKIT_RIGHT: + rightAligned = true; + break; + case LEFT: + case WEBKIT_LEFT: + case CENTER: + case WEBKIT_CENTER: + 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 int RenderText::widthFromCache(const Font& f, int start, int len, int xPos, HashSet* fallbackFonts, GlyphOverflow* glyphOverflow) const +{ + if (f.isFixedPitch() && !f.isSmallCaps() && m_isAllASCII) { + int monospaceCharacterWidth = f.spaceWidth(); + int tabWidth = allowTabs() ? monospaceCharacterWidth * 8 : 0; + int w = 0; + bool isSpace; + bool previousCharWasSpace = true; // FIXME: Preserves historical behavior, but seems wrong for start > 0. + 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') { + w += tabWidth ? tabWidth - ((xPos + w) % tabWidth) : monospaceCharacterWidth; + isSpace = true; + } else + isSpace = false; + } else { + w += monospaceCharacterWidth; + isSpace = false; + } + if (isSpace && !previousCharWasSpace) + w += f.wordSpacing(); + previousCharWasSpace = isSpace; + } + return w; + } + + return f.width(TextRun(text()->characters() + start, len, allowTabs(), xPos), fallbackFonts, glyphOverflow); +} + +void RenderText::trimmedPrefWidths(int leadWidth, + int& beginMinW, bool& beginWS, + int& endMinW, bool& endWS, + bool& hasBreakableChar, bool& hasBreak, + int& beginMaxW, int& endMaxW, + int& minW, int& maxW, bool& stripFrontSpaces) +{ + bool collapseWhiteSpace = style()->collapseWhiteSpace(); + if (!collapseWhiteSpace) + stripFrontSpaces = false; + + if (m_hasTab || preferredLogicalWidthsDirty()) + computePreferredLogicalWidths(leadWidth); + + beginWS = !stripFrontSpaces && m_hasBeginWS; + endWS = m_hasEndWS; + + int len = textLength(); + + if (!len || (stripFrontSpaces && text()->containsOnlyWhitespace())) { + beginMinW = 0; + endMinW = 0; + beginMaxW = 0; + endMaxW = 0; + minW = 0; + maxW = 0; + hasBreak = false; + return; + } + + minW = m_minWidth; + maxW = m_maxWidth; + + beginMinW = m_beginMinWidth; + endMinW = m_endMinWidth; + + 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& f = style()->font(); // FIXME: This ignores first-line. + if (stripFrontSpaces) { + const UChar space = ' '; + int spaceWidth = f.width(TextRun(&space, 1)); + maxW -= spaceWidth; + } else + maxW += f.wordSpacing(); + } + + stripFrontSpaces = collapseWhiteSpace && m_hasEndWS; + + if (!style()->autoWrap() || minW > maxW) + minW = maxW; + + // 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; + beginMaxW = maxW; + endMaxW = maxW; + for (int i = 0; i < len; i++) { + int linelen = 0; + while (i + linelen < len && text[i + linelen] != '\n') + linelen++; + + if (linelen) { + endMaxW = widthFromCache(f, i, linelen, leadWidth + endMaxW, 0, 0); + if (firstLine) { + firstLine = false; + leadWidth = 0; + beginMaxW = endMaxW; + } + i += linelen; + } else if (firstLine) { + beginMaxW = 0; + firstLine = false; + leadWidth = 0; + } + + if (i == len - 1) + // A 
 run that ends with a newline, as in, e.g.,
+                // 
Some text\n\nMore text

+                endMaxW = 0;
+        }
+    }
+}
+
+static inline bool isSpaceAccordingToStyle(UChar c, RenderStyle* style)
+{
+    return c == ' ' || (c == noBreakSpace && style->nbspMode() == SPACE);
+}
+
+int RenderText::minPreferredLogicalWidth() const
+{
+    if (preferredLogicalWidthsDirty())
+        const_cast(this)->computePreferredLogicalWidths(0);
+        
+    return m_minWidth;
+}
+
+int RenderText::maxPreferredLogicalWidth() const
+{
+    if (preferredLogicalWidthsDirty())
+        const_cast(this)->computePreferredLogicalWidths(0);
+        
+    return m_maxWidth;
+}
+
+void RenderText::computePreferredLogicalWidths(int leadWidth)
+{
+    HashSet fallbackFonts;
+    GlyphOverflow glyphOverflow;
+    computePreferredLogicalWidths(leadWidth, fallbackFonts, glyphOverflow);
+    if (fallbackFonts.isEmpty() && !glyphOverflow.left && !glyphOverflow.right && !glyphOverflow.top && !glyphOverflow.bottom)
+        m_knownToHaveNoOverflowAndNoFallbackFonts = true;
+}
+
+void RenderText::computePreferredLogicalWidths(int leadWidth, HashSet& fallbackFonts, GlyphOverflow& glyphOverflow)
+{
+    ASSERT(m_hasTab || preferredLogicalWidthsDirty() || !m_knownToHaveNoOverflowAndNoFallbackFonts);
+
+    m_minWidth = 0;
+    m_beginMinWidth = 0;
+    m_endMinWidth = 0;
+    m_maxWidth = 0;
+
+    if (isBR())
+        return;
+
+    int currMinWidth = 0;
+    int currMaxWidth = 0;
+    m_hasBreakableChar = false;
+    m_hasBreak = false;
+    m_hasTab = false;
+    m_hasBeginWS = false;
+    m_hasEndWS = false;
+
+    const Font& f = style()->font(); // FIXME: This ignores first-line.
+    int wordSpacing = style()->wordSpacing();
+    int len = textLength();
+    const UChar* txt = characters();
+    bool needsWordSpacing = false;
+    bool ignoringSpaces = false;
+    bool isSpace = false;
+    bool firstWord = true;
+    bool firstLine = true;
+    int nextBreakable = -1;
+    int lastWordBoundary = 0;
+
+    int firstGlyphLeftOverflow = -1;
+
+    bool breakNBSP = style()->autoWrap() && style()->nbspMode() == SPACE;
+    bool breakAll = (style()->wordBreak() == BreakAllWordBreak || style()->wordBreak() == BreakWordBreak) && style()->autoWrap();
+
+    for (int i = 0; i < len; i++) {
+        UChar c = txt[i];
+
+        bool previousCharacterIsSpace = isSpace;
+
+        bool isNewline = false;
+        if (c == '\n') {
+            if (style()->preserveNewline()) {
+                m_hasBreak = true;
+                isNewline = true;
+                isSpace = false;
+            } else
+                isSpace = true;
+        } else if (c == '\t') {
+            if (!style()->collapseWhiteSpace()) {
+                m_hasTab = true;
+                isSpace = false;
+            } else
+                isSpace = true;
+        } else
+            isSpace = c == ' ';
+
+        if ((isSpace || isNewline) && !i)
+            m_hasBeginWS = true;
+        if ((isSpace || isNewline) && i == len - 1)
+            m_hasEndWS = true;
+
+        if (!ignoringSpaces && style()->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, &fallbackFonts, &glyphOverflow);
+            if (firstGlyphLeftOverflow < 0)
+                firstGlyphLeftOverflow = glyphOverflow.left;
+            lastWordBoundary = i + 1;
+            continue;
+        }
+
+        bool hasBreak = breakAll || isBreakable(txt, i, len, nextBreakable, breakNBSP);
+        bool betweenWords = true;
+        int j = i;
+        while (c != '\n' && !isSpaceAccordingToStyle(c, style()) && c != '\t' && c != softHyphen) {
+            j++;
+            if (j == len)
+                break;
+            c = txt[j];
+            if (isBreakable(txt, j, len, nextBreakable, breakNBSP))
+                break;
+            if (breakAll) {
+                betweenWords = false;
+                break;
+            }
+        }
+
+        int wordLen = j - i;
+        if (wordLen) {
+            int w = widthFromCache(f, i, wordLen, leadWidth + currMaxWidth, &fallbackFonts, &glyphOverflow);
+            if (firstGlyphLeftOverflow < 0)
+                firstGlyphLeftOverflow = glyphOverflow.left;
+            currMinWidth += w;
+            if (betweenWords) {
+                if (lastWordBoundary == i)
+                    currMaxWidth += w;
+                else
+                    currMaxWidth += widthFromCache(f, lastWordBoundary, j - lastWordBoundary, leadWidth + currMaxWidth, &fallbackFonts, &glyphOverflow);
+                lastWordBoundary = j;
+            }
+
+            bool isSpace = (j < len) && isSpaceAccordingToStyle(c, style());
+            bool isCollapsibleWhiteSpace = (j < len) && style()->isCollapsibleWhiteSpace(c);
+            if (j < len && style()->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_beginMinWidth = hasBreak ? 0 : w;
+            }
+            m_endMinWidth = w;
+
+            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 (!style()->autoWrap())
+                        m_beginMinWidth = currMaxWidth;
+                }
+
+                if (currMaxWidth > m_maxWidth)
+                    m_maxWidth = currMaxWidth;
+                currMaxWidth = 0;
+            } else {
+                currMaxWidth += f.width(TextRun(txt + i, 1, allowTabs(), leadWidth + currMaxWidth));
+                glyphOverflow.right = 0;
+                needsWordSpacing = isSpace && !previousCharacterIsSpace && i == len - 1;
+            }
+            ASSERT(lastWordBoundary == i);
+            lastWordBoundary++;
+        }
+    }
+
+    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 (!style()->autoWrap())
+        m_minWidth = m_maxWidth;
+
+    if (style()->whiteSpace() == PRE) {
+        if (firstLine)
+            m_beginMinWidth = m_maxWidth;
+        m_endMinWidth = currMaxWidth;
+    }
+
+    setPreferredLogicalWidthsDirty(false);
+}
+
+bool RenderText::isAllCollapsibleWhitespace()
+{
+    int length = textLength();
+    const UChar* text = characters();
+    for (int i = 0; i < length; i++) {
+        if (!style()->isCollapsibleWhiteSpace(text[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);
+}
+
+IntPoint RenderText::firstRunOrigin() const
+{
+    return IntPoint(firstRunX(), firstRunY());
+}
+
+int RenderText::firstRunX() const
+{
+    return m_firstTextBox ? m_firstTextBox->m_x : 0;
+}
+
+int RenderText::firstRunY() const
+{
+    return m_firstTextBox ? m_firstTextBox->m_y : 0;
+}
+    
+void RenderText::setSelectionState(SelectionState state)
+{
+    InlineTextBox* box;
+
+    RenderObject::setSelectionState(state);
+    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 != 0 && startPos == endPos)
+                startPos = endPos - 1;
+        } else if (selectionState() == SelectionEnd)
+            startPos = 0;
+
+        for (box = firstTextBox(); box; box = box->nextTextBox()) {
+            if (box->isSelected(startPos, endPos)) {
+                RootInlineBox* line = box->root();
+                if (line)
+                    line->setHasSelectedChildren(true);
+            }
+        }
+    } else {
+        for (box = firstTextBox(); box; box = box->nextTextBox()) {
+            RootInlineBox* line = box->root();
+            if (line)
+                line->setHasSelectedChildren(state == SelectionInside);
+        }
+    }
+
+    // The returned value can be null in case of an orphaned tree.
+    if (RenderBlock* cb = containingBlock())
+        cb->setSelectionState(state);
+}
+
+void RenderText::setTextWithOffset(PassRefPtr text, unsigned offset, unsigned len, bool force)
+{
+    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()) {
+        // 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;
+                if (!dirtiedLines) {
+                    // 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(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);
+}
+
+static inline bool isInlineFlowOrEmptyText(const RenderObject* o)
+{
+    if (o->isRenderInline())
+        return true;
+    if (!o->isText())
+        return false;
+    StringImpl* text = toRenderText(o)->text();
+    if (!text)
+        return true;
+    return !text->length();
+}
+
+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())
+            prev = (*previousString)[previousString->length() - 1];
+    return prev;
+}
+
+void RenderText::transformText(String& text) const
+{
+    ASSERT(style());
+    switch (style()->textTransform()) {
+    case TTNONE:
+        break;
+    case CAPITALIZE:
+        makeCapitalized(&text, previousCharacter());
+        break;
+    case UPPERCASE:
+        text.makeUpper();
+        break;
+    case LOWERCASE:
+        text.makeLower();
+        break;
+    }
+}
+
+void RenderText::setTextInternal(PassRefPtr text)
+{
+    ASSERT(text);
+    m_text = text;
+    if (m_needsTranscoding) {
+        const TextEncoding* encoding = document()->decoder() ? &document()->decoder()->encoding() : 0;
+        fontTranscoder().convert(m_text, style()->font().fontDescription(), encoding);
+    }
+    ASSERT(m_text);
+
+    if (style()) {
+        transformText(m_text);
+
+        // 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:
+            m_text.makeSecure(whiteBullet);
+            break;
+        case TSDISC:
+            m_text.makeSecure(bullet);
+            break;
+        case TSSQUARE:
+            m_text.makeSecure(blackSquare);
+        }
+    }
+
+    ASSERT(m_text);
+    ASSERT(!isBR() || (textLength() == 1 && m_text[0] == '\n'));
+
+    m_isAllASCII = m_text.containsOnlyASCII();
+}
+
+void RenderText::setText(PassRefPtr text, bool force)
+{
+    ASSERT(text);
+
+    if (!force && equal(m_text.impl(), text.get()))
+        return;
+
+    setTextInternal(text);
+    setNeedsLayoutAndPrefWidthsRecalc();
+    m_knownToHaveNoOverflowAndNoFallbackFonts = false;
+    
+    AXObjectCache* axObjectCache = document()->axObjectCache();
+    if (axObjectCache->accessibilityEnabled())
+        axObjectCache->contentChanged(this);
+}
+
+String RenderText::textWithoutTranscoding() const
+{
+    // If m_text isn't transcoded or is secure, we can just return the modified text.
+    if (!m_needsTranscoding || style()->textSecurity() != TSNONE)
+        return text();
+
+    // Otherwise, we should use original text. If text-transform is
+    // specified, we should transform the text on the fly.
+    String text = originalText();
+    if (style())
+        transformText(text);
+    return text;
+}
+
+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;
+}
+#ifdef ANDROID_DISABLE_ROUNDING_HACKS
+static bool disableRoundingHacks(RenderText* renderText)
+{
+    RenderObject* renderer = renderText;
+    while (renderer) {
+        if (renderer->isTextControl()) {
+            return true;
+        }
+        renderer = renderer->parent();
+    }
+    return false;
+}
+#endif
+
+InlineTextBox* RenderText::createTextBox()
+{
+#ifdef ANDROID_DISABLE_ROUNDING_HACKS
+    return new (renderArena()) InlineTextBox(this, disableRoundingHacks(this));
+#else
+    return new (renderArena()) InlineTextBox(this);
+#endif
+}
+
+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 = static_cast(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(renderArena());
+        return;
+    }
+
+    m_containsReversedText |= !s->isLeftToRightDirection();
+}
+
+unsigned RenderText::width(unsigned from, unsigned len, int xPos, bool firstLine, HashSet* fallbackFonts, GlyphOverflow* glyphOverflow) const
+{
+    if (from >= textLength())
+        return 0;
+
+    if (from + len > textLength())
+        len = textLength() - from;
+
+    return width(from, len, style(firstLine)->font(), xPos, fallbackFonts, glyphOverflow);
+}
+
+unsigned RenderText::width(unsigned from, unsigned len, const Font& f, int xPos, HashSet* fallbackFonts, GlyphOverflow* glyphOverflow) const
+{
+    ASSERT(from + len <= textLength());
+    if (!characters())
+        return 0;
+
+    int w;
+    if (&f == &style()->font()) {
+        if (!style()->preserveNewline() && !from && len == textLength()) {
+            if (fallbackFonts) {
+                ASSERT(glyphOverflow);
+                if (preferredLogicalWidthsDirty() || !m_knownToHaveNoOverflowAndNoFallbackFonts) {
+                    const_cast(this)->computePreferredLogicalWidths(0, *fallbackFonts, *glyphOverflow);
+                    if (fallbackFonts->isEmpty() && !glyphOverflow->left && !glyphOverflow->right && !glyphOverflow->top && !glyphOverflow->bottom)
+                        m_knownToHaveNoOverflowAndNoFallbackFonts = true;
+                }
+                w = m_maxWidth;
+            } else
+                w = maxPreferredLogicalWidth();
+        } else
+            w = widthFromCache(f, from, len, xPos, fallbackFonts, glyphOverflow);
+    } else
+        w = f.width(TextRun(text()->characters() + from, len, allowTabs(), xPos), 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.
+        int logicalLeftSide = 0;
+        int 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();
+        
+        int x = isHorizontal ? logicalLeftSide : firstTextBox()->x();
+        int y = isHorizontal ? firstTextBox()->y() : logicalLeftSide;
+        int width = isHorizontal ? logicalRightSide - logicalLeftSide : lastTextBox()->logicalBottom() - x;
+        int height = isHorizontal ? lastTextBox()->logicalBottom() - y : logicalRightSide - logicalLeftSide;
+        result = IntRect(x, y, width, height);
+    }
+
+    return result;
+}
+
+IntRect RenderText::clippedOverflowRectForRepaint(RenderBoxModelObject* repaintContainer)
+{
+    RenderObject* cb = containingBlock();
+    // The containing block may be an ancestor of repaintContainer, but we need to do a repaintContainer-relative repaint.
+    if (repaintContainer && repaintContainer != cb) {
+        if (!cb->isDescendantOf(repaintContainer))
+            return repaintContainer->clippedOverflowRectForRepaint(repaintContainer);
+    }
+    return cb->clippedOverflowRectForRepaint(repaintContainer);
+}
+
+IntRect RenderText::selectionRectForRepaint(RenderBoxModelObject* repaintContainer, bool clipToVisibleContent)
+{
+    ASSERT(!needsLayout());
+
+    if (selectionState() == SelectionNone)
+        return IntRect();
+    RenderBlock* cb = containingBlock();
+    if (!cb)
+        return IntRect();
+
+    // 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();
+
+    IntRect rect;
+    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
+        rect.unite(box->selectionRect(0, 0, 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(minOffset, box->start());
+    return minOffset;
+}
+
+int RenderText::caretMaxOffset() const
+{
+    InlineTextBox* box = lastTextBox();
+    if (!box)
+        return textLength();
+    int maxOffset = box->start() + box->len();
+    for (box = box->prevTextBox(); box; box = box->prevTextBox())
+        maxOffset = max(maxOffset, box->start() + box->len());
+    return maxOffset;
+}
+
+unsigned RenderText::caretMaxRenderedOffset() const
+{
+    int l = 0;
+    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
+        l += box->len();
+    return l;
+}
+
+int RenderText::previousOffset(int current) const
+{
+    StringImpl* si = m_text.impl();
+    TextBreakIterator* iterator = cursorMovementIterator(si->characters(), si->length());
+    if (!iterator)
+        return current - 1;
+
+    long result = textBreakPreceding(iterator, current);
+    if (result == TextBreakDone)
+        result = current - 1;
+
+#ifdef BUILDING_ON_TIGER
+    // ICU 3.2 allows character breaks before a half-width Katakana voiced mark.
+    if (static_cast(result) < si->length()) {
+        UChar character = (*si)[result];
+        if (character == 0xFF9E || character == 0xFF9F)
+            --result;
+    }
+#endif
+
+    return result;
+}
+
+#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;
+}
+
+int RenderText::previousOffsetForBackwardDeletion(int current) const
+{
+#if PLATFORM(MAC)
+    ASSERT(m_text);
+    StringImpl& text = *m_text.impl();
+    UChar32 character;
+    while (current > 0) {
+        if (U16_IS_TRAIL(text[--current]))
+            --current;
+        if (current < 0)
+            break;
+
+        UChar32 character = text.characterStartingAt(current);
+
+        // We don't combine characters in Armenian ... Limbu range for backward deletion.
+        if ((character >= 0x0530) && (character < 0x1950))
+            break;
+
+        if (u_isbase(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;
+        HangulState initialState;
+
+        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;
+
+        initialState = state;
+
+        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 Mac delete by one code point.
+    return current - 1;
+#endif
+}
+
+int RenderText::nextOffset(int current) const
+{
+    StringImpl* si = m_text.impl();
+    TextBreakIterator* iterator = cursorMovementIterator(si->characters(), si->length());
+    if (!iterator)
+        return current + 1;
+
+    long result = textBreakFollowing(iterator, current);
+    if (result == TextBreakDone)
+        result = current + 1;
+
+#ifdef BUILDING_ON_TIGER
+    // ICU 3.2 allows character breaks before a half-width Katakana voiced mark.
+    if (static_cast(result) < si->length()) {
+        UChar character = (*si)[result];
+        if (character == 0xFF9E || character == 0xFF9F)
+            ++result;
+    }
+#endif
+
+    return result;
+}
+
+#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
+
+} // namespace WebCore
-- 
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