Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 1817 insertions, 0 deletions

diff --git a/Source/WebCore/rendering/RenderText.cpp b/Source/WebCore/rendering/RenderText.cpp
new file mode 100644
index 000000000..8177503a7
--- /dev/null
+++ b/Source/WebCore/rendering/RenderText.cpp
@@ -0,0 +1,1817 @@
+/*
+ * (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 "EllipsisBox.h"
+#include "FloatQuad.h"
+#include "FontTranscoder.h"
+#include "FrameView.h"
+#include "InlineTextBox.h"
+#include "Range.h"
+#include "RenderArena.h"
+#include "RenderBlock.h"
+#include "RenderCombineText.h"
+#include "RenderLayer.h"
+#include "RenderView.h"
+#include "Settings.h"
+#include "Text.h"
+#include "TextBreakIterator.h"
+#include "TextResourceDecoder.h"
+#include "VisiblePosition.h"
+#include "break_lines.h"
+#include <wtf/AlwaysInline.h>
+#include <wtf/text/StringBuffer.h>
+#include <wtf/unicode/CharacterNames.h>
+
+using namespace std;
+using namespace WTF;
+using namespace Unicode;
+
+namespace WebCore {
+
+class SecureTextTimer;
+typedef HashMap<RenderText*, SecureTextTimer*> SecureTextTimerMap;
+static SecureTextTimerMap* gSecureTextTimers = 0;
+
+class SecureTextTimer : public TimerBase {
+public:
+    SecureTextTimer(RenderText* renderText)
+        : m_renderText(renderText)
+        , m_lastTypedCharacterOffset(-1)
+    {
+    }
+
+    void restartWithNewText(unsigned lastTypedCharacterOffset)
+    {
+        m_lastTypedCharacterOffset = lastTypedCharacterOffset;
+        startOneShot(m_renderText->document()->settings()->passwordEchoDurationInSeconds());
+    }
+    void invalidate() { m_lastTypedCharacterOffset = -1; }
+    unsigned lastTypedCharacterOffset() { return m_lastTypedCharacterOffset; }
+
+private:
+    virtual void fired()
+    {
+        ASSERT(gSecureTextTimers->contains(m_renderText));
+        m_renderText->setText(m_renderText->text(), 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 UChar* characters = string->characters();
+
+    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 (characters[i - 1] == noBreakSpace)
+            stringWithPrevious[i] = ' ';
+        else
+            stringWithPrevious[i] = characters[i - 1];
+    }
+
+    TextBreakIterator* boundary = wordBreakIterator(stringWithPrevious.characters(), length + 1);
+    if (!boundary)
+        return;
+
+    StringBuffer<UChar> data(length);
+
+    int32_t endOfWord;
+    int32_t startOfWord = textBreakFirst(boundary);
+    for (endOfWord = textBreakNext(boundary); endOfWord != TextBreakDone; startOfWord = endOfWord, endOfWord = textBreakNext(boundary)) {
+        if (startOfWord) // 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<StringImpl> 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();
+
+    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::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<StringImpl> textToTransform = originalText())
+            setText(textToTransform.release(), true);
+    }
+}
+
+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()) {
+        RenderArena* arena = renderArena();
+        InlineTextBox* next;
+        for (InlineTextBox* curr = firstTextBox(); curr; curr = next) {
+            next = curr->nextTextBox();
+            curr->destroy(arena);
+        }
+        m_firstTextBox = m_lastTextBox = 0;
+    }
+}
+
+PassRefPtr<StringImpl> RenderText::originalText() const
+{
+    Node* e = node();
+    return (e && e->isTextNode()) ? static_cast<Text*>(e)->dataImpl() : 0;
+}
+
+void RenderText::absoluteRects(Vector<LayoutRect>& rects, const LayoutPoint& accumulatedOffset) const
+{
+    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
+        rects.append(enclosingLayoutRect(FloatRect(accumulatedOffset + box->topLeft(), box->size())));
+}
+
+static FloatRect localQuadForTextBox(InlineTextBox* box, unsigned start, unsigned end, bool useSelectionHeight)
+{
+    unsigned realEnd = min(box->end() + 1, end);
+    IntRect 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->logicalHeight());
+                r.setY(box->y());
+            } else {
+                r.setWidth(box->logicalWidth());
+                r.setX(box->x());
+            }
+        }
+        return FloatRect(r);
+    }
+    return FloatRect();
+}
+
+void RenderText::absoluteRectsForRange(Vector<LayoutRect>& 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) {
+                // FIXME: localSelectionRect should switch to return FloatRect soon with the subpixellayout branch.
+                IntRect selectionRect = box->localSelectionRect(start, end);
+                if (box->isHorizontal()) {
+                    r.setHeight(selectionRect.height());
+                    r.setY(selectionRect.y());
+                } else {
+                    r.setWidth(selectionRect.width());
+                    r.setX(selectionRect.x());
+                }
+            }
+            rects.append(localToAbsoluteQuad(r, false, 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, false, 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, false, 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) {
+                // FIXME: localSelectionRect should switch to return FloatRect soon with the subpixellayout branch.
+                IntRect selectionRect = box->localSelectionRect(start, end);
+                if (box->isHorizontal()) {
+                    r.setHeight(selectionRect.height());
+                    r.setY(selectionRect.y());
+                } else {
+                    r.setWidth(selectionRect.width());
+                    r.setX(selectionRect.x());
+                }
+            }
+            quads.append(localToAbsoluteQuad(r, false, wasFixed));
+        } else {
+            FloatRect rect = localQuadForTextBox(box, start, end, useSelectionHeight);
+            if (!rect.isZero())
+                quads.append(localToAbsoluteQuad(rect, false, 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
+    if (pointLineDirection == box->logicalLeft())
+        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->prevOnLine() && pointLineDirection < box->logicalLeft())
+        return true;
+
+    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
+        shouldAffinityBeDownstream = UpstreamIfPositionIsNotAtStart;
+        return true;
+    }
+
+    return false;
+}
+
+static VisiblePosition createVisiblePositionForBox(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;
+    }
+    return box->renderer()->createVisiblePosition(offset, affinity);
+}
+
+static VisiblePosition createVisiblePositionAfterAdjustingOffsetForBiDi(const InlineTextBox* box, int offset, ShouldAffinityBeDownstream shouldAffinityBeDownstream)
+{
+    ASSERT(box);
+    ASSERT(box->renderer());
+    ASSERT(offset >= 0);
+
+    if (offset && static_cast<unsigned>(offset) < box->len())
+        return createVisiblePositionForBox(box, box->start() + offset, shouldAffinityBeDownstream);
+
+    bool positionIsAtStartOfBox = !offset;
+    if (positionIsAtStartOfBox == box->isLeftToRightDirection()) {
+        // offset is on the left edge
+
+        const InlineBox* prevBox = box->prevLeafChild();
+        if ((prevBox && prevBox->bidiLevel() == box->bidiLevel())
+            || box->renderer()->containingBlock()->style()->direction() == box->direction()) // FIXME: left on 12CBA
+            return createVisiblePositionForBox(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->prevLeafChild();
+            } while (prevBox && prevBox->bidiLevel() > box->bidiLevel());
+            return createVisiblePositionForBox(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->nextLeafChild();
+            } while (nextBox && nextBox->bidiLevel() >= box->bidiLevel());
+            return createVisiblePositionForBox(rightmostBox,
+                box->isLeftToRightDirection() ? rightmostBox->caretMaxOffset() : rightmostBox->caretMinOffset(), shouldAffinityBeDownstream);
+        }
+
+        return createVisiblePositionForBox(box, box->caretRightmostOffset(), shouldAffinityBeDownstream);
+    }
+
+    const InlineBox* nextBox = box->nextLeafChild();
+    if ((nextBox && nextBox->bidiLevel() == box->bidiLevel())
+        || box->renderer()->containingBlock()->style()->direction() == box->direction())
+        return createVisiblePositionForBox(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->nextLeafChild();
+        } while (nextBox && nextBox->bidiLevel() > box->bidiLevel());
+        return createVisiblePositionForBox(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->prevLeafChild();
+        } while (prevBox && prevBox->bidiLevel() >= box->bidiLevel());
+        return createVisiblePositionForBox(leftmostBox,
+            box->isLeftToRightDirection() ? leftmostBox->caretMinOffset() : leftmostBox->caretMaxOffset(), shouldAffinityBeDownstream);
+    }
+
+    return createVisiblePositionForBox(box, box->caretLeftmostOffset(), shouldAffinityBeDownstream);
+}
+
+VisiblePosition RenderText::positionForPoint(const LayoutPoint& 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;
+
+    LayoutUnit pointLineDirection = firstTextBox()->isHorizontal() ? point.x() : point.y();
+    LayoutUnit 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 createVisiblePositionAfterAdjustingOffsetForBiDi(firstTextBox(), offset, UpstreamIfPositionIsNotAtStart);
+    }
+    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 createVisiblePositionAfterAdjustingOffsetForBiDi(lastTextBox(), offset, AlwaysUpstream);
+    }
+
+    InlineTextBox* lastBoxAbove = 0;
+    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
+        RootInlineBox* rootBox = box->root();
+        if (pointBlockDirection >= rootBox->selectionTop() || pointBlockDirection >= rootBox->lineTop()) {
+            LayoutUnit bottom = rootBox->selectionBottom();
+            if (rootBox->nextRootBox())
+                bottom = min(bottom, rootBox->nextRootBox()->lineTop());
+
+            if (pointBlockDirection < bottom) {
+                ShouldAffinityBeDownstream shouldAffinityBeDownstream;
+                offset = box->offsetForPosition(pointLineDirection);
+                if (lineDirectionPointFitsInBox(pointLineDirection, box, shouldAffinityBeDownstream))
+                    return createVisiblePositionAfterAdjustingOffsetForBiDi(box, offset, shouldAffinityBeDownstream);
+            }
+            lastBoxAbove = box;
+        }
+    }
+
+    return createVisiblePosition(lastBoxAbove ? lastBoxAbove->start() + lastBoxAbove->len() : 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;
+    if (style()->autoWrap()) {
+        leftEdge = 0;
+        rightEdge = cb->logicalWidth();
+    } else {
+        leftEdge = min(static_cast<float>(0), rootLeft);
+        rightEdge = max(static_cast<float>(cb->logicalWidth()), 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;
+    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, 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.isSmallCaps() && m_isAllASCII && (!glyphOverflow || !glyphOverflow->computeBounds)) {
+        float monospaceCharacterWidth = f.spaceWidth();
+        float tabWidth = allowTabs() ? monospaceCharacterWidth * 8 : 0;
+        float 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 - fmodf(xPos + w, tabWidth) : monospaceCharacterWidth;
+                    isSpace = true;
+                } else
+                    isSpace = false;
+            } else {
+                w += monospaceCharacterWidth;
+                isSpace = false;
+            }
+            if (isSpace && !previousCharWasSpace)
+                w += f.wordSpacing();
+            previousCharWasSpace = isSpace;
+        }
+        return w;
+    }
+
+    TextRun run = RenderBlock::constructTextRun(const_cast<RenderText*>(this), f, text()->characters() + start, len, style());
+    run.setCharactersLength(textLength() - start);
+    ASSERT(run.charactersLength() >= run.length());
+
+    run.setAllowTabs(allowTabs());
+    run.setXPos(xPos);
+    return f.width(run, fallbackFonts, glyphOverflow);
+}
+
+void RenderText::trimmedPrefWidths(float leadWidth,
+                                   float& beginMinW, bool& beginWS,
+                                   float& endMinW, bool& endWS,
+                                   bool& hasBreakableChar, bool& hasBreak,
+                                   float& beginMaxW, float& endMaxW,
+                                   float& minW, float& 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& font = style()->font(); // FIXME: This ignores first-line.
+        if (stripFrontSpaces) {
+            const UChar space = ' ';
+            float spaceWidth = font.width(RenderBlock::constructTextRun(this, font, &space, 1, style()));
+            maxW -= spaceWidth;
+        } else
+            maxW += font.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 <pre> run that ends with a newline, as in, e.g.,
+                // <pre>Some text\n\n<span>More text</pre>
+                endMaxW = 0;
+        }
+    }
+}
+
+static inline bool isSpaceAccordingToStyle(UChar c, RenderStyle* style)
+{
+    return c == ' ' || (c == noBreakSpace && style->nbspMode() == SPACE);
+}
+
+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;
+}
+
+void RenderText::computePreferredLogicalWidths(float leadWidth, HashSet<const SimpleFontData*>& fallbackFonts, GlyphOverflow& glyphOverflow)
+{
+    ASSERT(m_hasTab || preferredLogicalWidthsDirty() || !m_knownToHaveNoOverflowAndNoFallbackFonts);
+
+    m_minWidth = 0;
+    m_beginMinWidth = 0;
+    m_endMinWidth = 0;
+    m_maxWidth = 0;
+
+    if (isBR())
+        return;
+
+    float currMinWidth = 0;
+    float 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.
+    float wordSpacing = style()->wordSpacing();
+    int len = textLength();
+    const UChar* txt = characters();
+    LazyLineBreakIterator breakIterator(txt, len, style()->locale());
+    bool needsWordSpacing = false;
+    bool ignoringSpaces = false;
+    bool isSpace = false;
+    bool firstWord = true;
+    bool firstLine = true;
+    int nextBreakable = -1;
+    int lastWordBoundary = 0;
+
+    // Non-zero only when kerning is enabled, in which case we measure words with their trailing
+    // space, then subtract its width.
+    float wordTrailingSpaceWidth = f.typesettingFeatures() & Kerning ? f.width(RenderBlock::constructTextRun(this, f, &space, 1, style())) : 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(breakIterator, i, 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(breakIterator, j, nextBreakable, breakNBSP))
+                break;
+            if (breakAll) {
+                betweenWords = false;
+                break;
+            }
+        }
+
+        int wordLen = j - i;
+        if (wordLen) {
+            bool isSpace = (j < len) && isSpaceAccordingToStyle(c, style());
+            float w;
+            if (wordTrailingSpaceWidth && isSpace)
+                w = widthFromCache(f, i, wordLen + 1, leadWidth + currMaxWidth, &fallbackFonts, &glyphOverflow) - wordTrailingSpaceWidth;
+            else
+                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 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 {
+                TextRun run = RenderBlock::constructTextRun(this, f, txt + i, 1, style());
+                run.setCharactersLength(len - i);
+                ASSERT(run.charactersLength() >= run.length());
+
+                run.setAllowTabs(allowTabs());
+                run.setXPos(leadWidth + currMaxWidth);
+
+                currMaxWidth += f.width(run);
+                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);
+}
+
+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)
+{
+    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<StringImpl> 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 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.makeUpper();
+        break;
+    case LOWERCASE:
+        text.makeLower();
+        break;
+    }
+}
+
+void RenderText::setTextInternal(PassRefPtr<StringImpl> 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()) {
+        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();
+}
+
+void RenderText::secureText(UChar mask)
+{
+    if (!m_text.length())
+        return;
+
+    int lastTypedCharacterOffsetToReveal = -1;
+    String revealedText;
+    SecureTextTimer* secureTextTimer = gSecureTextTimers ? gSecureTextTimers->get(this) : 0;
+    if (secureTextTimer && secureTextTimer->isActive()) {
+        lastTypedCharacterOffsetToReveal = secureTextTimer->lastTypedCharacterOffset();
+        if (lastTypedCharacterOffsetToReveal >= 0)
+            revealedText.append(m_text[lastTypedCharacterOffsetToReveal]);
+    }
+
+    m_text.fill(mask);
+    if (lastTypedCharacterOffsetToReveal >= 0) {
+        m_text.replace(lastTypedCharacterOffsetToReveal, 1, revealedText);
+        // 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);
+    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();
+    applyTextTransform(style(), text, previousCharacter());
+    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;
+}
+
+InlineTextBox* RenderText::createTextBox()
+{
+    return new (renderArena()) 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(renderArena());
+        return;
+    }
+
+    m_containsReversedText |= !s->isLeftToRightDirection();
+}
+
+float RenderText::width(unsigned from, unsigned len, float xPos, 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, fallbackFonts, glyphOverflow);
+}
+
+float RenderText::width(unsigned from, unsigned len, const Font& f, float xPos, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const
+{
+    ASSERT(from + len <= textLength());
+    if (!characters())
+        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, fallbackFonts, glyphOverflow);
+    } else {
+        TextRun run = RenderBlock::constructTextRun(const_cast<RenderText*>(this), f, text()->characters() + from, len, style());
+        run.setCharactersLength(textLength() - from);
+        ASSERT(run.charactersLength() >= run.length());
+
+        run.setAllowTabs(allowTabs());
+        run.setXPos(xPos);
+        w = f.width(run, fallbackFonts, glyphOverflow);
+    }
+
+    return w;
+}
+
+LayoutRect RenderText::linesBoundingBox() const
+{
+    LayoutRect 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 = numeric_limits<LayoutUnit>::max();
+    LayoutUnit logicalRightSide = numeric_limits<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(RenderBoxModelObject* 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(RenderBoxModelObject* 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
+    LayoutUnit 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
+{
+    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;
+
+
+    return result;
+}
+
+#if PLATFORM(MAC) || PLATFORM(CHROMIUM) && OS(MAC_OS_X)
+
+#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 PLATFORM(MAC) || PLATFORM(CHROMIUM) && OS(MAC_OS_X)
+    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;
+        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.
+    if (U16_IS_TRAIL(m_text[--current]))
+        --current;
+    if (current < 0)
+        current = 0;
+    return current;
+#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;
+
+
+    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
+
+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);
+}
+
+} // namespace WebCore