src/third_party/WebKit/Source/core/rendering/InlineFlowBox.cpp

   1 /*
   2  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public License
  15  * along with this library; see the file COPYING.LIB.  If not, write to
  16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  */
  19
  20 #include "config.h"
  21 #include "core/rendering/InlineFlowBox.h"
  22
  23 #include "core/CSSPropertyNames.h"
  24 #include "core/dom/Document.h"
  25 #include "core/paint/BoxPainter.h"
  26 #include "core/paint/InlineFlowBoxPainter.h"
  27 #include "core/rendering/HitTestResult.h"
  28 #include "core/rendering/InlineTextBox.h"
  29 #include "core/rendering/RenderBlock.h"
  30 #include "core/rendering/RenderInline.h"
  31 #include "core/rendering/RenderLayer.h"
  32 #include "core/rendering/RenderListMarker.h"
  33 #include "core/rendering/RenderObjectInlines.h"
  34 #include "core/rendering/RenderRubyBase.h"
  35 #include "core/rendering/RenderRubyRun.h"
  36 #include "core/rendering/RenderRubyText.h"
  37 #include "core/rendering/RenderView.h"
  38 #include "core/rendering/RootInlineBox.h"
  39 #include "platform/fonts/Font.h"
  40 #include "platform/graphics/GraphicsContextStateSaver.h"
  41
  42 #include <math.h>
  43
  44 namespace blink {
  45
  46 struct SameSizeAsInlineFlowBox : public InlineBox {
  47     void* pointers[5];
  48     uint32_t bitfields : 23;
  49 };
  50
  51 COMPILE_ASSERT(sizeof(InlineFlowBox) == sizeof(SameSizeAsInlineFlowBox), InlineFlowBox_should_stay_small);
  52
  53 #if ENABLE(ASSERT)
  54
  55 InlineFlowBox::~InlineFlowBox()
  56 {
  57     if (!m_hasBadChildList)
  58         for (InlineBox* child = firstChild(); child; child = child->nextOnLine())
  59             child->setHasBadParent();
  60 }
  61
  62 #endif
  63
  64 LayoutUnit InlineFlowBox::getFlowSpacingLogicalWidth()
  65 {
  66     LayoutUnit totWidth = marginBorderPaddingLogicalLeft() + marginBorderPaddingLogicalRight();
  67     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
  68         if (curr->isInlineFlowBox())
  69             totWidth += toInlineFlowBox(curr)->getFlowSpacingLogicalWidth();
  70     }
  71     return totWidth;
  72 }
  73
  74 IntRect InlineFlowBox::roundedFrameRect() const
  75 {
  76     // Begin by snapping the x and y coordinates to the nearest pixel.
  77     int snappedX = lroundf(x());
  78     int snappedY = lroundf(y());
  79
  80     int snappedMaxX = lroundf(x() + width());
  81     int snappedMaxY = lroundf(y() + height());
  82
  83     return IntRect(snappedX, snappedY, snappedMaxX - snappedX, snappedMaxY - snappedY);
  84 }
  85
  86 static void setHasTextDescendantsOnAncestors(InlineFlowBox* box)
  87 {
  88     while (box && !box->hasTextDescendants()) {
  89         box->setHasTextDescendants();
  90         box = box->parent();
  91     }
  92 }
  93
  94 void InlineFlowBox::addToLine(InlineBox* child)
  95 {
  96     ASSERT(!child->parent());
  97     ASSERT(!child->nextOnLine());
  98     ASSERT(!child->prevOnLine());
  99     checkConsistency();
 100
 101     child->setParent(this);
 102     if (!m_firstChild) {
 103         m_firstChild = child;
 104         m_lastChild = child;
 105     } else {
 106         m_lastChild->setNextOnLine(child);
 107         child->setPrevOnLine(m_lastChild);
 108         m_lastChild = child;
 109     }
 110     child->setFirstLineStyleBit(isFirstLineStyle());
 111     child->setIsHorizontal(isHorizontal());
 112     if (child->isText()) {
 113         if (child->renderer().parent() == renderer())
 114             m_hasTextChildren = true;
 115         setHasTextDescendantsOnAncestors(this);
 116     } else if (child->isInlineFlowBox()) {
 117         if (toInlineFlowBox(child)->hasTextDescendants())
 118             setHasTextDescendantsOnAncestors(this);
 119     }
 120
 121     if (descendantsHaveSameLineHeightAndBaseline() && !child->renderer().isOutOfFlowPositioned()) {
 122         RenderStyle* parentStyle = renderer().style(isFirstLineStyle());
 123         RenderStyle* childStyle = child->renderer().style(isFirstLineStyle());
 124         bool shouldClearDescendantsHaveSameLineHeightAndBaseline = false;
 125         if (child->renderer().isReplaced())
 126             shouldClearDescendantsHaveSameLineHeightAndBaseline = true;
 127         else if (child->isText()) {
 128             if (child->renderer().isBR() || child->renderer().parent() != renderer()) {
 129                 if (!parentStyle->font().fontMetrics().hasIdenticalAscentDescentAndLineGap(childStyle->font().fontMetrics())
 130                     || parentStyle->lineHeight() != childStyle->lineHeight()
 131                     || (parentStyle->verticalAlign() != BASELINE && !isRootInlineBox()) || childStyle->verticalAlign() != BASELINE)
 132                     shouldClearDescendantsHaveSameLineHeightAndBaseline = true;
 133             }
 134             if (childStyle->hasTextCombine() || childStyle->textEmphasisMark() != TextEmphasisMarkNone)
 135                 shouldClearDescendantsHaveSameLineHeightAndBaseline = true;
 136         } else {
 137             if (child->renderer().isBR()) {
 138                 // FIXME: This is dumb. We only turn off because current layout test results expect the <br> to be 0-height on the baseline.
 139                 // Other than making a zillion tests have to regenerate results, there's no reason to ditch the optimization here.
 140                 shouldClearDescendantsHaveSameLineHeightAndBaseline = true;
 141             } else {
 142                 ASSERT(isInlineFlowBox());
 143                 InlineFlowBox* childFlowBox = toInlineFlowBox(child);
 144                 // Check the child's bit, and then also check for differences in font, line-height, vertical-align
 145                 if (!childFlowBox->descendantsHaveSameLineHeightAndBaseline()
 146                     || !parentStyle->font().fontMetrics().hasIdenticalAscentDescentAndLineGap(childStyle->font().fontMetrics())
 147                     || parentStyle->lineHeight() != childStyle->lineHeight()
 148                     || (parentStyle->verticalAlign() != BASELINE && !isRootInlineBox()) || childStyle->verticalAlign() != BASELINE
 149                     || childStyle->hasBorder() || childStyle->hasPadding() || childStyle->hasTextCombine())
 150                     shouldClearDescendantsHaveSameLineHeightAndBaseline = true;
 151             }
 152         }
 153
 154         if (shouldClearDescendantsHaveSameLineHeightAndBaseline)
 155             clearDescendantsHaveSameLineHeightAndBaseline();
 156     }
 157
 158     if (!child->renderer().isOutOfFlowPositioned()) {
 159         if (child->isText()) {
 160             RenderStyle* childStyle = child->renderer().style(isFirstLineStyle());
 161             if (childStyle->letterSpacing() < 0 || childStyle->textShadow() || childStyle->textEmphasisMark() != TextEmphasisMarkNone || childStyle->textStrokeWidth())
 162                 child->clearKnownToHaveNoOverflow();
 163         } else if (child->renderer().isReplaced()) {
 164             RenderBox& box = toRenderBox(child->renderer());
 165             if (box.hasRenderOverflow() || box.hasSelfPaintingLayer())
 166                 child->clearKnownToHaveNoOverflow();
 167         } else if (!child->renderer().isBR() && (child->renderer().style(isFirstLineStyle())->boxShadow() || child->boxModelObject()->hasSelfPaintingLayer()
 168             || (child->renderer().isListMarker() && !toRenderListMarker(child->renderer()).isInside())
 169             || child->renderer().style(isFirstLineStyle())->hasBorderImageOutsets()
 170             || child->renderer().style(isFirstLineStyle())->hasOutline())) {
 171             child->clearKnownToHaveNoOverflow();
 172         }
 173
 174         if (knownToHaveNoOverflow() && child->isInlineFlowBox() && !toInlineFlowBox(child)->knownToHaveNoOverflow())
 175             clearKnownToHaveNoOverflow();
 176     }
 177
 178     checkConsistency();
 179 }
 180
 181 void InlineFlowBox::removeChild(InlineBox* child, MarkLineBoxes markDirty)
 182 {
 183     checkConsistency();
 184
 185     if (markDirty == MarkLineBoxesDirty && !isDirty())
 186         dirtyLineBoxes();
 187
 188     root().childRemoved(child);
 189
 190     if (child == m_firstChild)
 191         m_firstChild = child->nextOnLine();
 192     if (child == m_lastChild)
 193         m_lastChild = child->prevOnLine();
 194     if (child->nextOnLine())
 195         child->nextOnLine()->setPrevOnLine(child->prevOnLine());
 196     if (child->prevOnLine())
 197         child->prevOnLine()->setNextOnLine(child->nextOnLine());
 198
 199     child->setParent(0);
 200
 201     checkConsistency();
 202 }
 203
 204 void InlineFlowBox::deleteLine()
 205 {
 206     InlineBox* child = firstChild();
 207     InlineBox* next = 0;
 208     while (child) {
 209         ASSERT(this == child->parent());
 210         next = child->nextOnLine();
 211 #if ENABLE(ASSERT)
 212         child->setParent(0);
 213 #endif
 214         child->deleteLine();
 215         child = next;
 216     }
 217 #if ENABLE(ASSERT)
 218     m_firstChild = 0;
 219     m_lastChild = 0;
 220 #endif
 221
 222     removeLineBoxFromRenderObject();
 223     destroy();
 224 }
 225
 226 void InlineFlowBox::removeLineBoxFromRenderObject()
 227 {
 228     rendererLineBoxes()->removeLineBox(this);
 229 }
 230
 231 void InlineFlowBox::extractLine()
 232 {
 233     if (!extracted())
 234         extractLineBoxFromRenderObject();
 235     for (InlineBox* child = firstChild(); child; child = child->nextOnLine())
 236         child->extractLine();
 237 }
 238
 239 void InlineFlowBox::extractLineBoxFromRenderObject()
 240 {
 241     rendererLineBoxes()->extractLineBox(this);
 242 }
 243
 244 void InlineFlowBox::attachLine()
 245 {
 246     if (extracted())
 247         attachLineBoxToRenderObject();
 248     for (InlineBox* child = firstChild(); child; child = child->nextOnLine())
 249         child->attachLine();
 250 }
 251
 252 void InlineFlowBox::attachLineBoxToRenderObject()
 253 {
 254     rendererLineBoxes()->attachLineBox(this);
 255 }
 256
 257 void InlineFlowBox::adjustPosition(float dx, float dy)
 258 {
 259     InlineBox::adjustPosition(dx, dy);
 260     for (InlineBox* child = firstChild(); child; child = child->nextOnLine())
 261         child->adjustPosition(dx, dy);
 262     if (m_overflow)
 263         m_overflow->move(dx, dy); // FIXME: Rounding error here since overflow was pixel snapped, but nobody other than list markers passes non-integral values here.
 264 }
 265
 266 RenderLineBoxList* InlineFlowBox::rendererLineBoxes() const
 267 {
 268     return toRenderInline(renderer()).lineBoxes();
 269 }
 270
 271 static inline bool isLastChildForRenderer(RenderObject* ancestor, RenderObject* child)
 272 {
 273     if (!child)
 274         return false;
 275
 276     if (child == ancestor)
 277         return true;
 278
 279     RenderObject* curr = child;
 280     RenderObject* parent = curr->parent();
 281     while (parent && (!parent->isRenderBlock() || parent->isInline())) {
 282         if (parent->slowLastChild() != curr)
 283             return false;
 284         if (parent == ancestor)
 285             return true;
 286
 287         curr = parent;
 288         parent = curr->parent();
 289     }
 290
 291     return true;
 292 }
 293
 294 static bool isAnsectorAndWithinBlock(RenderObject* ancestor, RenderObject* child)
 295 {
 296     RenderObject* object = child;
 297     while (object && (!object->isRenderBlock() || object->isInline())) {
 298         if (object == ancestor)
 299             return true;
 300         object = object->parent();
 301     }
 302     return false;
 303 }
 304
 305 void InlineFlowBox::determineSpacingForFlowBoxes(bool lastLine, bool isLogicallyLastRunWrapped, RenderObject* logicallyLastRunRenderer)
 306 {
 307     // All boxes start off open.  They will not apply any margins/border/padding on
 308     // any side.
 309     bool includeLeftEdge = false;
 310     bool includeRightEdge = false;
 311
 312     // The root inline box never has borders/margins/padding.
 313     if (parent()) {
 314         bool ltr = renderer().style()->isLeftToRightDirection();
 315
 316         // Check to see if all initial lines are unconstructed.  If so, then
 317         // we know the inline began on this line (unless we are a continuation).
 318         RenderLineBoxList* lineBoxList = rendererLineBoxes();
 319         if (!lineBoxList->firstLineBox()->isConstructed() && !renderer().isInlineElementContinuation()) {
 320             if (renderer().style()->boxDecorationBreak() == DCLONE)
 321                 includeLeftEdge = includeRightEdge = true;
 322             else if (ltr && lineBoxList->firstLineBox() == this)
 323                 includeLeftEdge = true;
 324             else if (!ltr && lineBoxList->lastLineBox() == this)
 325                 includeRightEdge = true;
 326         }
 327
 328         if (!lineBoxList->lastLineBox()->isConstructed()) {
 329             RenderInline& inlineFlow = toRenderInline(renderer());
 330             bool isLastObjectOnLine = !isAnsectorAndWithinBlock(&renderer(), logicallyLastRunRenderer) || (isLastChildForRenderer(&renderer(), logicallyLastRunRenderer) && !isLogicallyLastRunWrapped);
 331
 332             // We include the border under these conditions:
 333             // (1) The next line was not created, or it is constructed. We check the previous line for rtl.
 334             // (2) The logicallyLastRun is not a descendant of this renderer.
 335             // (3) The logicallyLastRun is a descendant of this renderer, but it is the last child of this renderer and it does not wrap to the next line.
 336             // (4) The decoration break is set to clone therefore there will be borders on every sides.
 337             if (renderer().style()->boxDecorationBreak() == DCLONE)
 338                 includeLeftEdge = includeRightEdge = true;
 339             else if (ltr) {
 340                 if (!nextLineBox()
 341                     && ((lastLine || isLastObjectOnLine) && !inlineFlow.continuation()))
 342                     includeRightEdge = true;
 343             } else {
 344                 if ((!prevLineBox() || prevLineBox()->isConstructed())
 345                     && ((lastLine || isLastObjectOnLine) && !inlineFlow.continuation()))
 346                     includeLeftEdge = true;
 347             }
 348         }
 349     }
 350
 351     setEdges(includeLeftEdge, includeRightEdge);
 352
 353     // Recur into our children.
 354     for (InlineBox* currChild = firstChild(); currChild; currChild = currChild->nextOnLine()) {
 355         if (currChild->isInlineFlowBox()) {
 356             InlineFlowBox* currFlow = toInlineFlowBox(currChild);
 357             currFlow->determineSpacingForFlowBoxes(lastLine, isLogicallyLastRunWrapped, logicallyLastRunRenderer);
 358         }
 359     }
 360 }
 361
 362 float InlineFlowBox::placeBoxesInInlineDirection(float logicalLeft, bool& needsWordSpacing)
 363 {
 364     // Set our x position.
 365     beginPlacingBoxRangesInInlineDirection(logicalLeft);
 366
 367     float startLogicalLeft = logicalLeft;
 368     logicalLeft += borderLogicalLeft() + paddingLogicalLeft();
 369
 370     float minLogicalLeft = startLogicalLeft;
 371     float maxLogicalRight = logicalLeft;
 372
 373     placeBoxRangeInInlineDirection(firstChild(), 0, logicalLeft, minLogicalLeft, maxLogicalRight, needsWordSpacing);
 374
 375     logicalLeft += borderLogicalRight() + paddingLogicalRight();
 376     endPlacingBoxRangesInInlineDirection(startLogicalLeft, logicalLeft, minLogicalLeft, maxLogicalRight);
 377     return logicalLeft;
 378 }
 379
 380 float InlineFlowBox::placeBoxRangeInInlineDirection(InlineBox* firstChild, InlineBox* lastChild,
 381     float& logicalLeft, float& minLogicalLeft, float& maxLogicalRight, bool& needsWordSpacing)
 382 {
 383     for (InlineBox* curr = firstChild; curr && curr != lastChild; curr = curr->nextOnLine()) {
 384         if (curr->renderer().isText()) {
 385             InlineTextBox* text = toInlineTextBox(curr);
 386             RenderText& rt = text->renderer();
 387             float space = 0;
 388             if (rt.textLength()) {
 389                 if (needsWordSpacing && isSpaceOrNewline(rt.characterAt(text->start())))
 390                     space = rt.style(isFirstLineStyle())->font().fontDescription().wordSpacing();
 391                 needsWordSpacing = !isSpaceOrNewline(rt.characterAt(text->end()));
 392             }
 393             if (isLeftToRightDirection()) {
 394                 logicalLeft += space;
 395                 text->setLogicalLeft(logicalLeft);
 396             } else {
 397                 text->setLogicalLeft(logicalLeft);
 398                 logicalLeft += space;
 399             }
 400             if (knownToHaveNoOverflow())
 401                 minLogicalLeft = std::min(logicalLeft, minLogicalLeft);
 402             logicalLeft += text->logicalWidth();
 403             if (knownToHaveNoOverflow())
 404                 maxLogicalRight = std::max(logicalLeft, maxLogicalRight);
 405         } else {
 406             if (curr->renderer().isOutOfFlowPositioned()) {
 407                 if (curr->renderer().parent()->style()->isLeftToRightDirection()) {
 408                     curr->setLogicalLeft(logicalLeft);
 409                 } else {
 410                     // Our offset that we cache needs to be from the edge of the right border box and
 411                     // not the left border box.  We have to subtract |x| from the width of the block
 412                     // (which can be obtained from the root line box).
 413                     curr->setLogicalLeft(root().block().logicalWidth() - logicalLeft);
 414                 }
 415                 continue; // The positioned object has no effect on the width.
 416             }
 417             if (curr->renderer().isRenderInline()) {
 418                 InlineFlowBox* flow = toInlineFlowBox(curr);
 419                 logicalLeft += flow->marginLogicalLeft();
 420                 if (knownToHaveNoOverflow())
 421                     minLogicalLeft = std::min(logicalLeft, minLogicalLeft);
 422                 logicalLeft = flow->placeBoxesInInlineDirection(logicalLeft, needsWordSpacing);
 423                 if (knownToHaveNoOverflow())
 424                     maxLogicalRight = std::max(logicalLeft, maxLogicalRight);
 425                 logicalLeft += flow->marginLogicalRight();
 426             } else if (!curr->renderer().isListMarker() || toRenderListMarker(curr->renderer()).isInside()) {
 427                 // The box can have a different writing-mode than the overall line, so this is a bit complicated.
 428                 // Just get all the physical margin and overflow values by hand based off |isVertical|.
 429                 LayoutUnit logicalLeftMargin = isHorizontal() ? curr->boxModelObject()->marginLeft() : curr->boxModelObject()->marginTop();
 430                 LayoutUnit logicalRightMargin = isHorizontal() ? curr->boxModelObject()->marginRight() : curr->boxModelObject()->marginBottom();
 431
 432                 logicalLeft += logicalLeftMargin;
 433                 curr->setLogicalLeft(logicalLeft);
 434                 if (knownToHaveNoOverflow())
 435                     minLogicalLeft = std::min(logicalLeft, minLogicalLeft);
 436                 logicalLeft += curr->logicalWidth();
 437                 if (knownToHaveNoOverflow())
 438                     maxLogicalRight = std::max(logicalLeft, maxLogicalRight);
 439                 logicalLeft += logicalRightMargin;
 440                 // If we encounter any space after this inline block then ensure it is treated as the space between two words.
 441                 needsWordSpacing = true;
 442             }
 443         }
 444     }
 445     return logicalLeft;
 446 }
 447
 448 bool InlineFlowBox::requiresIdeographicBaseline(const GlyphOverflowAndFallbackFontsMap& textBoxDataMap) const
 449 {
 450     if (isHorizontal())
 451         return false;
 452
 453     if (renderer().style(isFirstLineStyle())->fontDescription().nonCJKGlyphOrientation() == NonCJKGlyphOrientationUpright
 454         || renderer().style(isFirstLineStyle())->font().primaryFont()->hasVerticalGlyphs())
 455         return true;
 456
 457     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 458         if (curr->renderer().isOutOfFlowPositioned())
 459             continue; // Positioned placeholders don't affect calculations.
 460
 461         if (curr->isInlineFlowBox()) {
 462             if (toInlineFlowBox(curr)->requiresIdeographicBaseline(textBoxDataMap))
 463                 return true;
 464         } else {
 465             if (curr->renderer().style(isFirstLineStyle())->font().primaryFont()->hasVerticalGlyphs())
 466                 return true;
 467
 468             const Vector<const SimpleFontData*>* usedFonts = 0;
 469             if (curr->isInlineTextBox()) {
 470                 GlyphOverflowAndFallbackFontsMap::const_iterator it = textBoxDataMap.find(toInlineTextBox(curr));
 471                 usedFonts = it == textBoxDataMap.end() ? 0 : &it->value.first;
 472             }
 473
 474             if (usedFonts) {
 475                 for (size_t i = 0; i < usedFonts->size(); ++i) {
 476                     if (usedFonts->at(i)->hasVerticalGlyphs())
 477                         return true;
 478                 }
 479             }
 480         }
 481     }
 482
 483     return false;
 484 }
 485
 486 void InlineFlowBox::adjustMaxAscentAndDescent(int& maxAscent, int& maxDescent, int maxPositionTop, int maxPositionBottom)
 487 {
 488     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 489         // The computed lineheight needs to be extended for the
 490         // positioned elements
 491         if (curr->renderer().isOutOfFlowPositioned())
 492             continue; // Positioned placeholders don't affect calculations.
 493         if (curr->verticalAlign() == TOP || curr->verticalAlign() == BOTTOM) {
 494             int lineHeight = curr->lineHeight();
 495             if (curr->verticalAlign() == TOP) {
 496                 if (maxAscent + maxDescent < lineHeight)
 497                     maxDescent = lineHeight - maxAscent;
 498             }
 499             else {
 500                 if (maxAscent + maxDescent < lineHeight)
 501                     maxAscent = lineHeight - maxDescent;
 502             }
 503
 504             if (maxAscent + maxDescent >= std::max(maxPositionTop, maxPositionBottom))
 505                 break;
 506         }
 507
 508         if (curr->isInlineFlowBox())
 509             toInlineFlowBox(curr)->adjustMaxAscentAndDescent(maxAscent, maxDescent, maxPositionTop, maxPositionBottom);
 510     }
 511 }
 512
 513 void InlineFlowBox::computeLogicalBoxHeights(RootInlineBox* rootBox, LayoutUnit& maxPositionTop, LayoutUnit& maxPositionBottom,
 514                                              int& maxAscent, int& maxDescent, bool& setMaxAscent, bool& setMaxDescent,
 515                                              bool strictMode, GlyphOverflowAndFallbackFontsMap& textBoxDataMap,
 516                                              FontBaseline baselineType, VerticalPositionCache& verticalPositionCache)
 517 {
 518     // The primary purpose of this function is to compute the maximal ascent and descent values for
 519     // a line. These values are computed based off the block's line-box-contain property, which indicates
 520     // what parts of descendant boxes have to fit within the line.
 521     //
 522     // The maxAscent value represents the distance of the highest point of any box (typically including line-height) from
 523     // the root box's baseline. The maxDescent value represents the distance of the lowest point of any box
 524     // (also typically including line-height) from the root box baseline. These values can be negative.
 525     //
 526     // A secondary purpose of this function is to store the offset of every box's baseline from the root box's
 527     // baseline. This information is cached in the logicalTop() of every box. We're effectively just using
 528     // the logicalTop() as scratch space.
 529     //
 530     // Because a box can be positioned such that it ends up fully above or fully below the
 531     // root line box, we only consider it to affect the maxAscent and maxDescent values if some
 532     // part of the box (EXCLUDING leading) is above (for ascent) or below (for descent) the root box's baseline.
 533     bool affectsAscent = false;
 534     bool affectsDescent = false;
 535     bool checkChildren = !descendantsHaveSameLineHeightAndBaseline();
 536
 537     if (isRootInlineBox()) {
 538         // Examine our root box.
 539         int ascent = 0;
 540         int descent = 0;
 541         rootBox->ascentAndDescentForBox(rootBox, textBoxDataMap, ascent, descent, affectsAscent, affectsDescent);
 542         if (strictMode || hasTextChildren() || (!checkChildren && hasTextDescendants())) {
 543             if (maxAscent < ascent || !setMaxAscent) {
 544                 maxAscent = ascent;
 545                 setMaxAscent = true;
 546             }
 547             if (maxDescent < descent || !setMaxDescent) {
 548                 maxDescent = descent;
 549                 setMaxDescent = true;
 550             }
 551         }
 552     }
 553
 554     if (!checkChildren)
 555         return;
 556
 557     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 558         if (curr->renderer().isOutOfFlowPositioned())
 559             continue; // Positioned placeholders don't affect calculations.
 560
 561         InlineFlowBox* inlineFlowBox = curr->isInlineFlowBox() ? toInlineFlowBox(curr) : 0;
 562
 563         bool affectsAscent = false;
 564         bool affectsDescent = false;
 565
 566         // The verticalPositionForBox function returns the distance between the child box's baseline
 567         // and the root box's baseline.  The value is negative if the child box's baseline is above the
 568         // root box's baseline, and it is positive if the child box's baseline is below the root box's baseline.
 569         curr->setLogicalTop(rootBox->verticalPositionForBox(curr, verticalPositionCache).toFloat());
 570
 571         int ascent = 0;
 572         int descent = 0;
 573         rootBox->ascentAndDescentForBox(curr, textBoxDataMap, ascent, descent, affectsAscent, affectsDescent);
 574
 575         LayoutUnit boxHeight = ascent + descent;
 576         if (curr->verticalAlign() == TOP) {
 577             if (maxPositionTop < boxHeight)
 578                 maxPositionTop = boxHeight;
 579         } else if (curr->verticalAlign() == BOTTOM) {
 580             if (maxPositionBottom < boxHeight)
 581                 maxPositionBottom = boxHeight;
 582         } else if (!inlineFlowBox || strictMode || inlineFlowBox->hasTextChildren() || (inlineFlowBox->descendantsHaveSameLineHeightAndBaseline() && inlineFlowBox->hasTextDescendants())
 583                    || inlineFlowBox->boxModelObject()->hasInlineDirectionBordersOrPadding()) {
 584             // Note that these values can be negative.  Even though we only affect the maxAscent and maxDescent values
 585             // if our box (excluding line-height) was above (for ascent) or below (for descent) the root baseline, once you factor in line-height
 586             // the final box can end up being fully above or fully below the root box's baseline!  This is ok, but what it
 587             // means is that ascent and descent (including leading), can end up being negative.  The setMaxAscent and
 588             // setMaxDescent booleans are used to ensure that we're willing to initially set maxAscent/Descent to negative
 589             // values.
 590             ascent -= curr->logicalTop();
 591             descent += curr->logicalTop();
 592             if (affectsAscent && (maxAscent < ascent || !setMaxAscent)) {
 593                 maxAscent = ascent;
 594                 setMaxAscent = true;
 595             }
 596
 597             if (affectsDescent && (maxDescent < descent || !setMaxDescent)) {
 598                 maxDescent = descent;
 599                 setMaxDescent = true;
 600             }
 601         }
 602
 603         if (inlineFlowBox)
 604             inlineFlowBox->computeLogicalBoxHeights(rootBox, maxPositionTop, maxPositionBottom, maxAscent, maxDescent,
 605                                                     setMaxAscent, setMaxDescent, strictMode, textBoxDataMap,
 606                                                     baselineType, verticalPositionCache);
 607     }
 608 }
 609
 610 void InlineFlowBox::placeBoxesInBlockDirection(LayoutUnit top, LayoutUnit maxHeight, int maxAscent, bool strictMode, LayoutUnit& lineTop, LayoutUnit& lineBottom, LayoutUnit& selectionBottom, bool& setLineTop,
 611                                                LayoutUnit& lineTopIncludingMargins, LayoutUnit& lineBottomIncludingMargins, bool& hasAnnotationsBefore, bool& hasAnnotationsAfter, FontBaseline baselineType)
 612 {
 613     bool isRootBox = isRootInlineBox();
 614     if (isRootBox) {
 615         const FontMetrics& fontMetrics = renderer().style(isFirstLineStyle())->fontMetrics();
 616         // RootInlineBoxes are always placed on at pixel boundaries in their logical y direction. Not doing
 617         // so results in incorrect rendering of text decorations, most notably underlines.
 618         setLogicalTop(roundToInt(top + maxAscent - fontMetrics.ascent(baselineType)));
 619     }
 620
 621     LayoutUnit adjustmentForChildrenWithSameLineHeightAndBaseline = 0;
 622     if (descendantsHaveSameLineHeightAndBaseline()) {
 623         adjustmentForChildrenWithSameLineHeightAndBaseline = logicalTop();
 624         if (parent())
 625             adjustmentForChildrenWithSameLineHeightAndBaseline += (boxModelObject()->borderBefore() + boxModelObject()->paddingBefore());
 626     }
 627
 628     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 629         if (curr->renderer().isOutOfFlowPositioned())
 630             continue; // Positioned placeholders don't affect calculations.
 631
 632         if (descendantsHaveSameLineHeightAndBaseline()) {
 633             curr->adjustBlockDirectionPosition(adjustmentForChildrenWithSameLineHeightAndBaseline.toFloat());
 634             continue;
 635         }
 636
 637         InlineFlowBox* inlineFlowBox = curr->isInlineFlowBox() ? toInlineFlowBox(curr) : 0;
 638         bool childAffectsTopBottomPos = true;
 639         if (curr->verticalAlign() == TOP)
 640             curr->setLogicalTop(top.toFloat());
 641         else if (curr->verticalAlign() == BOTTOM)
 642             curr->setLogicalTop((top + maxHeight - curr->lineHeight()).toFloat());
 643         else {
 644             if (!strictMode && inlineFlowBox && !inlineFlowBox->hasTextChildren() && !curr->boxModelObject()->hasInlineDirectionBordersOrPadding()
 645                 && !(inlineFlowBox->descendantsHaveSameLineHeightAndBaseline() && inlineFlowBox->hasTextDescendants()))
 646                 childAffectsTopBottomPos = false;
 647             LayoutUnit posAdjust = maxAscent - curr->baselinePosition(baselineType);
 648             curr->setLogicalTop(curr->logicalTop() + top + posAdjust);
 649         }
 650
 651         LayoutUnit newLogicalTop = curr->logicalTop();
 652         LayoutUnit newLogicalTopIncludingMargins = newLogicalTop;
 653         LayoutUnit boxHeight = curr->logicalHeight();
 654         LayoutUnit boxHeightIncludingMargins = boxHeight;
 655         LayoutUnit borderPaddingHeight = 0;
 656         if (curr->isText() || curr->isInlineFlowBox()) {
 657             const FontMetrics& fontMetrics = curr->renderer().style(isFirstLineStyle())->fontMetrics();
 658             newLogicalTop += curr->baselinePosition(baselineType) - fontMetrics.ascent(baselineType);
 659             if (curr->isInlineFlowBox()) {
 660                 RenderBoxModelObject& boxObject = toRenderBoxModelObject(curr->renderer());
 661                 newLogicalTop -= boxObject.style(isFirstLineStyle())->isHorizontalWritingMode() ? boxObject.borderTop() + boxObject.paddingTop() :
 662                     boxObject.borderRight() + boxObject.paddingRight();
 663                 borderPaddingHeight = boxObject.borderAndPaddingLogicalHeight();
 664             }
 665             newLogicalTopIncludingMargins = newLogicalTop;
 666         } else if (!curr->renderer().isBR()) {
 667             RenderBox& box = toRenderBox(curr->renderer());
 668             newLogicalTopIncludingMargins = newLogicalTop;
 669             LayoutUnit overSideMargin = curr->isHorizontal() ? box.marginTop() : box.marginRight();
 670             LayoutUnit underSideMargin = curr->isHorizontal() ? box.marginBottom() : box.marginLeft();
 671             newLogicalTop += overSideMargin;
 672             boxHeightIncludingMargins += overSideMargin + underSideMargin;
 673         }
 674
 675         curr->setLogicalTop(newLogicalTop.toFloat());
 676
 677         if (childAffectsTopBottomPos) {
 678             if (curr->renderer().isRubyRun()) {
 679                 // Treat the leading on the first and last lines of ruby runs as not being part of the overall lineTop/lineBottom.
 680                 // Really this is a workaround hack for the fact that ruby should have been done as line layout and not done using
 681                 // inline-block.
 682                 if (renderer().style()->isFlippedLinesWritingMode() == (curr->renderer().style()->rubyPosition() == RubyPositionAfter))
 683                     hasAnnotationsBefore = true;
 684                 else
 685                     hasAnnotationsAfter = true;
 686
 687                 RenderRubyRun& rubyRun = toRenderRubyRun(curr->renderer());
 688                 if (RenderRubyBase* rubyBase = rubyRun.rubyBase()) {
 689                     LayoutUnit bottomRubyBaseLeading = (curr->logicalHeight() - rubyBase->logicalBottom()) + rubyBase->logicalHeight() - (rubyBase->lastRootBox() ? rubyBase->lastRootBox()->lineBottom() : LayoutUnit());
 690                     LayoutUnit topRubyBaseLeading = rubyBase->logicalTop() + (rubyBase->firstRootBox() ? rubyBase->firstRootBox()->lineTop() : LayoutUnit());
 691                     newLogicalTop += !renderer().style()->isFlippedLinesWritingMode() ? topRubyBaseLeading : bottomRubyBaseLeading;
 692                     boxHeight -= (topRubyBaseLeading + bottomRubyBaseLeading);
 693                 }
 694             }
 695             if (curr->isInlineTextBox()) {
 696                 TextEmphasisPosition emphasisMarkPosition;
 697                 if (toInlineTextBox(curr)->getEmphasisMarkPosition(curr->renderer().style(isFirstLineStyle()), emphasisMarkPosition)) {
 698                     bool emphasisMarkIsOver = emphasisMarkPosition == TextEmphasisPositionOver;
 699                     if (emphasisMarkIsOver != curr->renderer().style(isFirstLineStyle())->isFlippedLinesWritingMode())
 700                         hasAnnotationsBefore = true;
 701                     else
 702                         hasAnnotationsAfter = true;
 703                 }
 704             }
 705
 706             if (!setLineTop) {
 707                 setLineTop = true;
 708                 lineTop = newLogicalTop;
 709                 lineTopIncludingMargins = std::min(lineTop, newLogicalTopIncludingMargins);
 710             } else {
 711                 lineTop = std::min(lineTop, newLogicalTop);
 712                 lineTopIncludingMargins = std::min(lineTop, std::min(lineTopIncludingMargins, newLogicalTopIncludingMargins));
 713             }
 714             selectionBottom = std::max(selectionBottom, newLogicalTop + boxHeight - borderPaddingHeight);
 715             lineBottom = std::max(lineBottom, newLogicalTop + boxHeight);
 716             lineBottomIncludingMargins = std::max(lineBottom, std::max(lineBottomIncludingMargins, newLogicalTopIncludingMargins + boxHeightIncludingMargins));
 717         }
 718
 719         // Adjust boxes to use their real box y/height and not the logical height (as dictated by
 720         // line-height).
 721         if (inlineFlowBox)
 722             inlineFlowBox->placeBoxesInBlockDirection(top, maxHeight, maxAscent, strictMode, lineTop, lineBottom, selectionBottom, setLineTop,
 723                                                       lineTopIncludingMargins, lineBottomIncludingMargins, hasAnnotationsBefore, hasAnnotationsAfter, baselineType);
 724     }
 725
 726     if (isRootBox) {
 727         if (strictMode || hasTextChildren() || (descendantsHaveSameLineHeightAndBaseline() && hasTextDescendants())) {
 728             if (!setLineTop) {
 729                 setLineTop = true;
 730                 lineTop = pixelSnappedLogicalTop();
 731                 lineTopIncludingMargins = lineTop;
 732             } else {
 733                 lineTop = std::min<LayoutUnit>(lineTop, pixelSnappedLogicalTop());
 734                 lineTopIncludingMargins = std::min(lineTop, lineTopIncludingMargins);
 735             }
 736             selectionBottom = std::max<LayoutUnit>(selectionBottom, pixelSnappedLogicalBottom());
 737             lineBottom = std::max<LayoutUnit>(lineBottom, pixelSnappedLogicalBottom());
 738             lineBottomIncludingMargins = std::max(lineBottom, lineBottomIncludingMargins);
 739         }
 740
 741         if (renderer().style()->isFlippedLinesWritingMode())
 742             flipLinesInBlockDirection(lineTopIncludingMargins, lineBottomIncludingMargins);
 743     }
 744 }
 745
 746 void InlineFlowBox::computeMaxLogicalTop(float& maxLogicalTop) const
 747 {
 748     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 749         if (curr->renderer().isOutOfFlowPositioned())
 750             continue; // Positioned placeholders don't affect calculations.
 751
 752         if (descendantsHaveSameLineHeightAndBaseline())
 753             continue;
 754
 755         maxLogicalTop = std::max<float>(maxLogicalTop, curr->y());
 756         float localMaxLogicalTop = 0;
 757         if (curr->isInlineFlowBox())
 758             toInlineFlowBox(curr)->computeMaxLogicalTop(localMaxLogicalTop);
 759         maxLogicalTop = std::max<float>(maxLogicalTop, localMaxLogicalTop);
 760     }
 761 }
 762
 763 void InlineFlowBox::flipLinesInBlockDirection(LayoutUnit lineTop, LayoutUnit lineBottom)
 764 {
 765     // Flip the box on the line such that the top is now relative to the lineBottom instead of the lineTop.
 766     setLogicalTop(lineBottom - (logicalTop() - lineTop) - logicalHeight());
 767
 768     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 769         if (curr->renderer().isOutOfFlowPositioned())
 770             continue; // Positioned placeholders aren't affected here.
 771
 772         if (curr->isInlineFlowBox())
 773             toInlineFlowBox(curr)->flipLinesInBlockDirection(lineTop, lineBottom);
 774         else
 775             curr->setLogicalTop(lineBottom - (curr->logicalTop() - lineTop) - curr->logicalHeight());
 776     }
 777 }
 778
 779 inline void InlineFlowBox::addBoxShadowVisualOverflow(LayoutRect& logicalVisualOverflow)
 780 {
 781     // box-shadow on root line boxes is applying to the block and not to the lines.
 782     if (!parent())
 783         return;
 784
 785     RenderStyle* style = renderer().style(isFirstLineStyle());
 786     if (!style->boxShadow())
 787         return;
 788
 789     LayoutUnit boxShadowLogicalTop;
 790     LayoutUnit boxShadowLogicalBottom;
 791     style->getBoxShadowBlockDirectionExtent(boxShadowLogicalTop, boxShadowLogicalBottom);
 792
 793     // Similar to how glyph overflow works, if our lines are flipped, then it's actually the opposite shadow that applies, since
 794     // the line is "upside down" in terms of block coordinates.
 795     LayoutUnit shadowLogicalTop = style->isFlippedLinesWritingMode() ? -boxShadowLogicalBottom : boxShadowLogicalTop;
 796     LayoutUnit shadowLogicalBottom = style->isFlippedLinesWritingMode() ? -boxShadowLogicalTop : boxShadowLogicalBottom;
 797
 798     LayoutUnit logicalTopVisualOverflow = std::min(pixelSnappedLogicalTop() + shadowLogicalTop, logicalVisualOverflow.y());
 799     LayoutUnit logicalBottomVisualOverflow = std::max(pixelSnappedLogicalBottom() + shadowLogicalBottom, logicalVisualOverflow.maxY());
 800
 801     LayoutUnit boxShadowLogicalLeft;
 802     LayoutUnit boxShadowLogicalRight;
 803     style->getBoxShadowInlineDirectionExtent(boxShadowLogicalLeft, boxShadowLogicalRight);
 804
 805     LayoutUnit logicalLeftVisualOverflow = std::min(pixelSnappedLogicalLeft() + boxShadowLogicalLeft, logicalVisualOverflow.x());
 806     LayoutUnit logicalRightVisualOverflow = std::max(pixelSnappedLogicalRight() + boxShadowLogicalRight, logicalVisualOverflow.maxX());
 807
 808     logicalVisualOverflow = LayoutRect(logicalLeftVisualOverflow, logicalTopVisualOverflow,
 809                                        logicalRightVisualOverflow - logicalLeftVisualOverflow, logicalBottomVisualOverflow - logicalTopVisualOverflow);
 810 }
 811
 812 inline void InlineFlowBox::addBorderOutsetVisualOverflow(LayoutRect& logicalVisualOverflow)
 813 {
 814     // border-image-outset on root line boxes is applying to the block and not to the lines.
 815     if (!parent())
 816         return;
 817
 818     RenderStyle* style = renderer().style(isFirstLineStyle());
 819     if (!style->hasBorderImageOutsets())
 820         return;
 821
 822     LayoutBoxExtent borderOutsets = style->borderImageOutsets();
 823
 824     LayoutUnit borderOutsetLogicalTop = borderOutsets.logicalTop(style->writingMode());
 825     LayoutUnit borderOutsetLogicalBottom = borderOutsets.logicalBottom(style->writingMode());
 826     LayoutUnit borderOutsetLogicalLeft = borderOutsets.logicalLeft(style->writingMode());
 827     LayoutUnit borderOutsetLogicalRight = borderOutsets.logicalRight(style->writingMode());
 828
 829     // Similar to how glyph overflow works, if our lines are flipped, then it's actually the opposite border that applies, since
 830     // the line is "upside down" in terms of block coordinates. vertical-rl and horizontal-bt are the flipped line modes.
 831     LayoutUnit outsetLogicalTop = style->isFlippedLinesWritingMode() ? borderOutsetLogicalBottom : borderOutsetLogicalTop;
 832     LayoutUnit outsetLogicalBottom = style->isFlippedLinesWritingMode() ? borderOutsetLogicalTop : borderOutsetLogicalBottom;
 833
 834     LayoutUnit logicalTopVisualOverflow = std::min(pixelSnappedLogicalTop() - outsetLogicalTop, logicalVisualOverflow.y());
 835     LayoutUnit logicalBottomVisualOverflow = std::max(pixelSnappedLogicalBottom() + outsetLogicalBottom, logicalVisualOverflow.maxY());
 836
 837     LayoutUnit outsetLogicalLeft = includeLogicalLeftEdge() ? borderOutsetLogicalLeft : LayoutUnit();
 838     LayoutUnit outsetLogicalRight = includeLogicalRightEdge() ? borderOutsetLogicalRight : LayoutUnit();
 839
 840     LayoutUnit logicalLeftVisualOverflow = std::min(pixelSnappedLogicalLeft() - outsetLogicalLeft, logicalVisualOverflow.x());
 841     LayoutUnit logicalRightVisualOverflow = std::max(pixelSnappedLogicalRight() + outsetLogicalRight, logicalVisualOverflow.maxX());
 842
 843     logicalVisualOverflow = LayoutRect(logicalLeftVisualOverflow, logicalTopVisualOverflow,
 844                                        logicalRightVisualOverflow - logicalLeftVisualOverflow, logicalBottomVisualOverflow - logicalTopVisualOverflow);
 845 }
 846
 847 inline void InlineFlowBox::addOutlineVisualOverflow(LayoutRect& logicalVisualOverflow)
 848 {
 849     // Outline on root line boxes is applied to the block and not to the lines.
 850     if (!parent())
 851         return;
 852
 853     RenderStyle* style = renderer().style(isFirstLineStyle());
 854     if (!style->hasOutline())
 855         return;
 856
 857     logicalVisualOverflow.inflate(style->outlineSize());
 858 }
 859
 860 inline void InlineFlowBox::addTextBoxVisualOverflow(InlineTextBox* textBox, GlyphOverflowAndFallbackFontsMap& textBoxDataMap, LayoutRect& logicalVisualOverflow)
 861 {
 862     if (textBox->knownToHaveNoOverflow())
 863         return;
 864
 865     RenderStyle* style = textBox->renderer().style(isFirstLineStyle());
 866
 867     GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.find(textBox);
 868     GlyphOverflow* glyphOverflow = it == textBoxDataMap.end() ? 0 : &it->value.second;
 869     bool isFlippedLine = style->isFlippedLinesWritingMode();
 870
 871     int topGlyphEdge = glyphOverflow ? (isFlippedLine ? glyphOverflow->bottom : glyphOverflow->top) : 0;
 872     int bottomGlyphEdge = glyphOverflow ? (isFlippedLine ? glyphOverflow->top : glyphOverflow->bottom) : 0;
 873     int leftGlyphEdge = glyphOverflow ? glyphOverflow->left : 0;
 874     int rightGlyphEdge = glyphOverflow ? glyphOverflow->right : 0;
 875
 876     int strokeOverflow = static_cast<int>(ceilf(style->textStrokeWidth() / 2.0f));
 877     int topGlyphOverflow = -strokeOverflow - topGlyphEdge;
 878     int bottomGlyphOverflow = strokeOverflow + bottomGlyphEdge;
 879     int leftGlyphOverflow = -strokeOverflow - leftGlyphEdge;
 880     int rightGlyphOverflow = strokeOverflow + rightGlyphEdge;
 881
 882     TextEmphasisPosition emphasisMarkPosition;
 883     if (style->textEmphasisMark() != TextEmphasisMarkNone && textBox->getEmphasisMarkPosition(style, emphasisMarkPosition)) {
 884         int emphasisMarkHeight = style->font().emphasisMarkHeight(style->textEmphasisMarkString());
 885         if ((emphasisMarkPosition == TextEmphasisPositionOver) == (!style->isFlippedLinesWritingMode()))
 886             topGlyphOverflow = std::min(topGlyphOverflow, -emphasisMarkHeight);
 887         else
 888             bottomGlyphOverflow = std::max(bottomGlyphOverflow, emphasisMarkHeight);
 889     }
 890
 891     // If letter-spacing is negative, we should factor that into right layout overflow. (Even in RTL, letter-spacing is
 892     // applied to the right, so this is not an issue with left overflow.
 893     rightGlyphOverflow -= std::min(0, (int)style->font().fontDescription().letterSpacing());
 894
 895     LayoutUnit textShadowLogicalTop;
 896     LayoutUnit textShadowLogicalBottom;
 897     style->getTextShadowBlockDirectionExtent(textShadowLogicalTop, textShadowLogicalBottom);
 898
 899     LayoutUnit childOverflowLogicalTop = std::min<LayoutUnit>(textShadowLogicalTop + topGlyphOverflow, topGlyphOverflow);
 900     LayoutUnit childOverflowLogicalBottom = std::max<LayoutUnit>(textShadowLogicalBottom + bottomGlyphOverflow, bottomGlyphOverflow);
 901
 902     LayoutUnit textShadowLogicalLeft;
 903     LayoutUnit textShadowLogicalRight;
 904     style->getTextShadowInlineDirectionExtent(textShadowLogicalLeft, textShadowLogicalRight);
 905
 906     LayoutUnit childOverflowLogicalLeft = std::min<LayoutUnit>(textShadowLogicalLeft + leftGlyphOverflow, leftGlyphOverflow);
 907     LayoutUnit childOverflowLogicalRight = std::max<LayoutUnit>(textShadowLogicalRight + rightGlyphOverflow, rightGlyphOverflow);
 908
 909     LayoutUnit logicalTopVisualOverflow = std::min(textBox->pixelSnappedLogicalTop() + childOverflowLogicalTop, logicalVisualOverflow.y());
 910     LayoutUnit logicalBottomVisualOverflow = std::max(textBox->pixelSnappedLogicalBottom() + childOverflowLogicalBottom, logicalVisualOverflow.maxY());
 911     LayoutUnit logicalLeftVisualOverflow = std::min(textBox->pixelSnappedLogicalLeft() + childOverflowLogicalLeft, logicalVisualOverflow.x());
 912     LayoutUnit logicalRightVisualOverflow = std::max(textBox->pixelSnappedLogicalRight() + childOverflowLogicalRight, logicalVisualOverflow.maxX());
 913
 914     logicalVisualOverflow = LayoutRect(logicalLeftVisualOverflow, logicalTopVisualOverflow,
 915                                        logicalRightVisualOverflow - logicalLeftVisualOverflow, logicalBottomVisualOverflow - logicalTopVisualOverflow);
 916
 917     textBox->setLogicalOverflowRect(logicalVisualOverflow);
 918 }
 919
 920 inline void InlineFlowBox::addReplacedChildOverflow(const InlineBox* inlineBox, LayoutRect& logicalLayoutOverflow, LayoutRect& logicalVisualOverflow)
 921 {
 922     RenderBox& box = toRenderBox(inlineBox->renderer());
 923
 924     // Visual overflow only propagates if the box doesn't have a self-painting layer.  This rectangle does not include
 925     // transforms or relative positioning (since those objects always have self-painting layers), but it does need to be adjusted
 926     // for writing-mode differences.
 927     if (!box.hasSelfPaintingLayer()) {
 928         LayoutRect childLogicalVisualOverflow = box.logicalVisualOverflowRectForPropagation(renderer().style());
 929         childLogicalVisualOverflow.move(inlineBox->logicalLeft(), inlineBox->logicalTop());
 930         logicalVisualOverflow.unite(childLogicalVisualOverflow);
 931     }
 932
 933     // Layout overflow internal to the child box only propagates if the child box doesn't have overflow clip set.
 934     // Otherwise the child border box propagates as layout overflow.  This rectangle must include transforms and relative positioning
 935     // and be adjusted for writing-mode differences.
 936     LayoutRect childLogicalLayoutOverflow = box.logicalLayoutOverflowRectForPropagation(renderer().style());
 937     childLogicalLayoutOverflow.move(inlineBox->logicalLeft(), inlineBox->logicalTop());
 938     logicalLayoutOverflow.unite(childLogicalLayoutOverflow);
 939 }
 940
 941 void InlineFlowBox::computeOverflow(LayoutUnit lineTop, LayoutUnit lineBottom, GlyphOverflowAndFallbackFontsMap& textBoxDataMap)
 942 {
 943     // If we know we have no overflow, we can just bail.
 944     if (knownToHaveNoOverflow()) {
 945         ASSERT(!m_overflow);
 946         return;
 947     }
 948
 949     if (m_overflow)
 950         m_overflow.clear();
 951
 952     // Visual overflow just includes overflow for stuff we need to issues paint invalidations for ourselves. Self-painting layers are ignored.
 953     // Layout overflow is used to determine scrolling extent, so it still includes child layers and also factors in
 954     // transforms, relative positioning, etc.
 955     LayoutRect logicalLayoutOverflow(enclosingLayoutRect(logicalFrameRectIncludingLineHeight(lineTop, lineBottom)));
 956     LayoutRect logicalVisualOverflow(logicalLayoutOverflow);
 957
 958     addBoxShadowVisualOverflow(logicalVisualOverflow);
 959     addBorderOutsetVisualOverflow(logicalVisualOverflow);
 960     addOutlineVisualOverflow(logicalVisualOverflow);
 961
 962     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
 963         if (curr->renderer().isOutOfFlowPositioned())
 964             continue; // Positioned placeholders don't affect calculations.
 965
 966         if (curr->renderer().isText()) {
 967             InlineTextBox* text = toInlineTextBox(curr);
 968             RenderText& rt = text->renderer();
 969             if (rt.isBR())
 970                 continue;
 971             LayoutRect textBoxOverflow(enclosingLayoutRect(text->logicalFrameRect()));
 972             addTextBoxVisualOverflow(text, textBoxDataMap, textBoxOverflow);
 973             logicalVisualOverflow.unite(textBoxOverflow);
 974         } else if (curr->renderer().isRenderInline()) {
 975             InlineFlowBox* flow = toInlineFlowBox(curr);
 976             flow->computeOverflow(lineTop, lineBottom, textBoxDataMap);
 977             if (!flow->boxModelObject()->hasSelfPaintingLayer())
 978                 logicalVisualOverflow.unite(flow->logicalVisualOverflowRect(lineTop, lineBottom));
 979             LayoutRect childLayoutOverflow = flow->logicalLayoutOverflowRect(lineTop, lineBottom);
 980             childLayoutOverflow.move(flow->boxModelObject()->relativePositionLogicalOffset());
 981             logicalLayoutOverflow.unite(childLayoutOverflow);
 982         } else {
 983             addReplacedChildOverflow(curr, logicalLayoutOverflow, logicalVisualOverflow);
 984         }
 985     }
 986
 987     setOverflowFromLogicalRects(logicalLayoutOverflow, logicalVisualOverflow, lineTop, lineBottom);
 988 }
 989
 990 void InlineFlowBox::setLayoutOverflow(const LayoutRect& rect, const LayoutRect& frameBox)
 991 {
 992     if (frameBox.contains(rect) || rect.isEmpty())
 993         return;
 994
 995     if (!m_overflow)
 996         m_overflow = adoptPtr(new RenderOverflow(frameBox, frameBox));
 997
 998     m_overflow->setLayoutOverflow(rect);
 999 }
1000
1001 void InlineFlowBox::setVisualOverflow(const LayoutRect& rect, const LayoutRect& frameBox)
1002 {
1003     if (frameBox.contains(rect) || rect.isEmpty())
1004         return;
1005
1006     if (!m_overflow)
1007         m_overflow = adoptPtr(new RenderOverflow(frameBox, frameBox));
1008
1009     m_overflow->setVisualOverflow(rect);
1010 }
1011
1012 void InlineFlowBox::setOverflowFromLogicalRects(const LayoutRect& logicalLayoutOverflow, const LayoutRect& logicalVisualOverflow, LayoutUnit lineTop, LayoutUnit lineBottom)
1013 {
1014     LayoutRect frameBox = enclosingLayoutRect(frameRectIncludingLineHeight(lineTop, lineBottom));
1015
1016     LayoutRect layoutOverflow(isHorizontal() ? logicalLayoutOverflow : logicalLayoutOverflow.transposedRect());
1017     setLayoutOverflow(layoutOverflow, frameBox);
1018
1019     LayoutRect visualOverflow(isHorizontal() ? logicalVisualOverflow : logicalVisualOverflow.transposedRect());
1020     setVisualOverflow(visualOverflow, frameBox);
1021 }
1022
1023 bool InlineFlowBox::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, LayoutUnit lineTop, LayoutUnit lineBottom)
1024 {
1025     LayoutRect overflowRect(visualOverflowRect(lineTop, lineBottom));
1026     flipForWritingMode(overflowRect);
1027     overflowRect.moveBy(accumulatedOffset);
1028     if (!locationInContainer.intersects(overflowRect))
1029         return false;
1030
1031     // Check children first.
1032     // We need to account for culled inline parents of the hit-tested nodes, so that they may also get included in area-based hit-tests.
1033     RenderObject* culledParent = 0;
1034     for (InlineBox* curr = lastChild(); curr; curr = curr->prevOnLine()) {
1035         if (curr->renderer().isText() || !curr->boxModelObject()->hasSelfPaintingLayer()) {
1036             RenderObject* newParent = 0;
1037             // Culled parents are only relevant for area-based hit-tests, so ignore it in point-based ones.
1038             if (locationInContainer.isRectBasedTest()) {
1039                 newParent = curr->renderer().parent();
1040                 if (newParent == renderer())
1041                     newParent = 0;
1042             }
1043             // Check the culled parent after all its children have been checked, to do this we wait until
1044             // we are about to test an element with a different parent.
1045             if (newParent != culledParent) {
1046                 if (!newParent || !newParent->isDescendantOf(culledParent)) {
1047                     while (culledParent && culledParent != renderer() && culledParent != newParent) {
1048                         if (culledParent->isRenderInline() && toRenderInline(culledParent)->hitTestCulledInline(request, result, locationInContainer, accumulatedOffset))
1049                             return true;
1050                         culledParent = culledParent->parent();
1051                     }
1052                 }
1053                 culledParent = newParent;
1054             }
1055             if (curr->nodeAtPoint(request, result, locationInContainer, accumulatedOffset, lineTop, lineBottom)) {
1056                 renderer().updateHitTestResult(result, locationInContainer.point() - toLayoutSize(accumulatedOffset));
1057                 return true;
1058             }
1059         }
1060     }
1061     // Check any culled ancestor of the final children tested.
1062     while (culledParent && culledParent != renderer()) {
1063         if (culledParent->isRenderInline() && toRenderInline(culledParent)->hitTestCulledInline(request, result, locationInContainer, accumulatedOffset))
1064             return true;
1065         culledParent = culledParent->parent();
1066     }
1067
1068     // Now check ourselves. Pixel snap hit testing.
1069     LayoutRect frameRect = roundedFrameRect();
1070     LayoutUnit minX = frameRect.x();
1071     LayoutUnit minY = frameRect.y();
1072     LayoutUnit width = frameRect.width();
1073     LayoutUnit height = frameRect.height();
1074
1075     // Constrain our hit testing to the line top and bottom if necessary.
1076     bool noQuirksMode = renderer().document().inNoQuirksMode();
1077     if (!noQuirksMode && !hasTextChildren() && !(descendantsHaveSameLineHeightAndBaseline() && hasTextDescendants())) {
1078         RootInlineBox& rootBox = root();
1079         LayoutUnit& top = isHorizontal() ? minY : minX;
1080         LayoutUnit& logicalHeight = isHorizontal() ? height : width;
1081         LayoutUnit bottom = std::min(rootBox.lineBottom(), top + logicalHeight);
1082         top = std::max(rootBox.lineTop(), top);
1083         logicalHeight = bottom - top;
1084     }
1085
1086     // Move x/y to our coordinates.
1087     LayoutRect rect(minX, minY, width, height);
1088     flipForWritingMode(rect);
1089     rect.moveBy(accumulatedOffset);
1090
1091     if (visibleToHitTestRequest(request) && locationInContainer.intersects(rect)) {
1092         renderer().updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - toLayoutSize(accumulatedOffset))); // Don't add in m_x or m_y here, we want coords in the containing block's space.
1093         if (!result.addNodeToRectBasedTestResult(renderer().node(), request, locationInContainer, rect))
1094             return true;
1095     }
1096
1097     return false;
1098 }
1099
1100 void InlineFlowBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset, LayoutUnit lineTop, LayoutUnit lineBottom)
1101 {
1102     InlineFlowBoxPainter(*this).paint(paintInfo, paintOffset, lineTop, lineBottom);
1103 }
1104
1105 bool InlineFlowBox::boxShadowCanBeAppliedToBackground(const FillLayer& lastBackgroundLayer) const
1106 {
1107     // The checks here match how paintFillLayer() decides whether to clip (if it does, the shadow
1108     // would be clipped out, so it has to be drawn separately).
1109     StyleImage* image = lastBackgroundLayer.image();
1110     bool hasFillImage = image && image->canRender(renderer(), renderer().style()->effectiveZoom());
1111     return (!hasFillImage && !renderer().style()->hasBorderRadius()) || (!prevLineBox() && !nextLineBox()) || !parent();
1112 }
1113
1114 void InlineFlowBox::constrainToLineTopAndBottomIfNeeded(LayoutRect& rect) const
1115 {
1116     bool noQuirksMode = renderer().document().inNoQuirksMode();
1117     if (!noQuirksMode && !hasTextChildren() && !(descendantsHaveSameLineHeightAndBaseline() && hasTextDescendants())) {
1118         const RootInlineBox& rootBox = root();
1119         LayoutUnit logicalTop = isHorizontal() ? rect.y() : rect.x();
1120         LayoutUnit logicalHeight = isHorizontal() ? rect.height() : rect.width();
1121         LayoutUnit bottom = std::min(rootBox.lineBottom(), logicalTop + logicalHeight);
1122         logicalTop = std::max(rootBox.lineTop(), logicalTop);
1123         logicalHeight = bottom - logicalTop;
1124         if (isHorizontal()) {
1125             rect.setY(logicalTop);
1126             rect.setHeight(logicalHeight);
1127         } else {
1128             rect.setX(logicalTop);
1129             rect.setWidth(logicalHeight);
1130         }
1131     }
1132 }
1133
1134 InlineBox* InlineFlowBox::firstLeafChild() const
1135 {
1136     InlineBox* leaf = 0;
1137     for (InlineBox* child = firstChild(); child && !leaf; child = child->nextOnLine())
1138         leaf = child->isLeaf() ? child : toInlineFlowBox(child)->firstLeafChild();
1139     return leaf;
1140 }
1141
1142 InlineBox* InlineFlowBox::lastLeafChild() const
1143 {
1144     InlineBox* leaf = 0;
1145     for (InlineBox* child = lastChild(); child && !leaf; child = child->prevOnLine())
1146         leaf = child->isLeaf() ? child : toInlineFlowBox(child)->lastLeafChild();
1147     return leaf;
1148 }
1149
1150 RenderObject::SelectionState InlineFlowBox::selectionState() const
1151 {
1152     return RenderObject::SelectionNone;
1153 }
1154
1155 bool InlineFlowBox::canAccommodateEllipsis(bool ltr, int blockEdge, int ellipsisWidth) const
1156 {
1157     for (InlineBox *box = firstChild(); box; box = box->nextOnLine()) {
1158         if (!box->canAccommodateEllipsis(ltr, blockEdge, ellipsisWidth))
1159             return false;
1160     }
1161     return true;
1162 }
1163
1164 float InlineFlowBox::placeEllipsisBox(bool ltr, float blockLeftEdge, float blockRightEdge, float ellipsisWidth, float &truncatedWidth, bool& foundBox)
1165 {
1166     float result = -1;
1167     // We iterate over all children, the foundBox variable tells us when we've found the
1168     // box containing the ellipsis.  All boxes after that one in the flow are hidden.
1169     // If our flow is ltr then iterate over the boxes from left to right, otherwise iterate
1170     // from right to left. Varying the order allows us to correctly hide the boxes following the ellipsis.
1171     InlineBox* box = ltr ? firstChild() : lastChild();
1172
1173     // NOTE: these will cross after foundBox = true.
1174     int visibleLeftEdge = blockLeftEdge;
1175     int visibleRightEdge = blockRightEdge;
1176
1177     while (box) {
1178         int currResult = box->placeEllipsisBox(ltr, visibleLeftEdge, visibleRightEdge, ellipsisWidth, truncatedWidth, foundBox);
1179         if (currResult != -1 && result == -1)
1180             result = currResult;
1181
1182         if (ltr) {
1183             visibleLeftEdge += box->logicalWidth();
1184             box = box->nextOnLine();
1185         }
1186         else {
1187             visibleRightEdge -= box->logicalWidth();
1188             box = box->prevOnLine();
1189         }
1190     }
1191     return result;
1192 }
1193
1194 void InlineFlowBox::clearTruncation()
1195 {
1196     for (InlineBox *box = firstChild(); box; box = box->nextOnLine())
1197         box->clearTruncation();
1198 }
1199
1200 LayoutUnit InlineFlowBox::computeOverAnnotationAdjustment(LayoutUnit allowedPosition) const
1201 {
1202     LayoutUnit result = 0;
1203     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
1204         if (curr->renderer().isOutOfFlowPositioned())
1205             continue; // Positioned placeholders don't affect calculations.
1206
1207         if (curr->isInlineFlowBox())
1208             result = std::max(result, toInlineFlowBox(curr)->computeOverAnnotationAdjustment(allowedPosition));
1209
1210         if (curr->renderer().isReplaced() && curr->renderer().isRubyRun() && curr->renderer().style()->rubyPosition() == RubyPositionBefore) {
1211             RenderRubyRun& rubyRun = toRenderRubyRun(curr->renderer());
1212             RenderRubyText* rubyText = rubyRun.rubyText();
1213             if (!rubyText)
1214                 continue;
1215
1216             if (!rubyRun.style()->isFlippedLinesWritingMode()) {
1217                 LayoutUnit topOfFirstRubyTextLine = rubyText->logicalTop() + (rubyText->firstRootBox() ? rubyText->firstRootBox()->lineTop() : LayoutUnit());
1218                 if (topOfFirstRubyTextLine >= 0)
1219                     continue;
1220                 topOfFirstRubyTextLine += curr->logicalTop();
1221                 result = std::max(result, allowedPosition - topOfFirstRubyTextLine);
1222             } else {
1223                 LayoutUnit bottomOfLastRubyTextLine = rubyText->logicalTop() + (rubyText->lastRootBox() ? rubyText->lastRootBox()->lineBottom() : rubyText->logicalHeight());
1224                 if (bottomOfLastRubyTextLine <= curr->logicalHeight())
1225                     continue;
1226                 bottomOfLastRubyTextLine += curr->logicalTop();
1227                 result = std::max(result, bottomOfLastRubyTextLine - allowedPosition);
1228             }
1229         }
1230
1231         if (curr->isInlineTextBox()) {
1232             RenderStyle* style = curr->renderer().style(isFirstLineStyle());
1233             TextEmphasisPosition emphasisMarkPosition;
1234             if (style->textEmphasisMark() != TextEmphasisMarkNone && toInlineTextBox(curr)->getEmphasisMarkPosition(style, emphasisMarkPosition) && emphasisMarkPosition == TextEmphasisPositionOver) {
1235                 if (!style->isFlippedLinesWritingMode()) {
1236                     int topOfEmphasisMark = curr->logicalTop() - style->font().emphasisMarkHeight(style->textEmphasisMarkString());
1237                     result = std::max(result, allowedPosition - topOfEmphasisMark);
1238                 } else {
1239                     int bottomOfEmphasisMark = curr->logicalBottom() + style->font().emphasisMarkHeight(style->textEmphasisMarkString());
1240                     result = std::max(result, bottomOfEmphasisMark - allowedPosition);
1241                 }
1242             }
1243         }
1244     }
1245     return result;
1246 }
1247
1248 LayoutUnit InlineFlowBox::computeUnderAnnotationAdjustment(LayoutUnit allowedPosition) const
1249 {
1250     LayoutUnit result = 0;
1251     for (InlineBox* curr = firstChild(); curr; curr = curr->nextOnLine()) {
1252         if (curr->renderer().isOutOfFlowPositioned())
1253             continue; // Positioned placeholders don't affect calculations.
1254
1255         if (curr->isInlineFlowBox())
1256             result = std::max(result, toInlineFlowBox(curr)->computeUnderAnnotationAdjustment(allowedPosition));
1257
1258         if (curr->renderer().isReplaced() && curr->renderer().isRubyRun() && curr->renderer().style()->rubyPosition() == RubyPositionAfter) {
1259             RenderRubyRun& rubyRun = toRenderRubyRun(curr->renderer());
1260             RenderRubyText* rubyText = rubyRun.rubyText();
1261             if (!rubyText)
1262                 continue;
1263
1264             if (rubyRun.style()->isFlippedLinesWritingMode()) {
1265                 LayoutUnit topOfFirstRubyTextLine = rubyText->logicalTop() + (rubyText->firstRootBox() ? rubyText->firstRootBox()->lineTop() : LayoutUnit());
1266                 if (topOfFirstRubyTextLine >= 0)
1267                     continue;
1268                 topOfFirstRubyTextLine += curr->logicalTop();
1269                 result = std::max(result, allowedPosition - topOfFirstRubyTextLine);
1270             } else {
1271                 LayoutUnit bottomOfLastRubyTextLine = rubyText->logicalTop() + (rubyText->lastRootBox() ? rubyText->lastRootBox()->lineBottom() : rubyText->logicalHeight());
1272                 if (bottomOfLastRubyTextLine <= curr->logicalHeight())
1273                     continue;
1274                 bottomOfLastRubyTextLine += curr->logicalTop();
1275                 result = std::max(result, bottomOfLastRubyTextLine - allowedPosition);
1276             }
1277         }
1278
1279         if (curr->isInlineTextBox()) {
1280             RenderStyle* style = curr->renderer().style(isFirstLineStyle());
1281             if (style->textEmphasisMark() != TextEmphasisMarkNone && style->textEmphasisPosition() == TextEmphasisPositionUnder) {
1282                 if (!style->isFlippedLinesWritingMode()) {
1283                     LayoutUnit bottomOfEmphasisMark = curr->logicalBottom() + style->font().emphasisMarkHeight(style->textEmphasisMarkString());
1284                     result = std::max(result, bottomOfEmphasisMark - allowedPosition);
1285                 } else {
1286                     LayoutUnit topOfEmphasisMark = curr->logicalTop() - style->font().emphasisMarkHeight(style->textEmphasisMarkString());
1287                     result = std::max(result, allowedPosition - topOfEmphasisMark);
1288                 }
1289             }
1290         }
1291     }
1292     return result;
1293 }
1294
1295 void InlineFlowBox::collectLeafBoxesInLogicalOrder(Vector<InlineBox*>& leafBoxesInLogicalOrder, CustomInlineBoxRangeReverse customReverseImplementation, void* userData) const
1296 {
1297     InlineBox* leaf = firstLeafChild();
1298
1299     // FIXME: The reordering code is a copy of parts from BidiResolver::createBidiRunsForLine, operating directly on InlineBoxes, instead of BidiRuns.
1300     // Investigate on how this code could possibly be shared.
1301     unsigned char minLevel = 128;
1302     unsigned char maxLevel = 0;
1303
1304     // First find highest and lowest levels, and initialize leafBoxesInLogicalOrder with the leaf boxes in visual order.
1305     for (; leaf; leaf = leaf->nextLeafChild()) {
1306         minLevel = std::min(minLevel, leaf->bidiLevel());
1307         maxLevel = std::max(maxLevel, leaf->bidiLevel());
1308         leafBoxesInLogicalOrder.append(leaf);
1309     }
1310
1311     if (renderer().style()->rtlOrdering() == VisualOrder)
1312         return;
1313
1314     // Reverse of reordering of the line (L2 according to Bidi spec):
1315     // L2. From the highest level found in the text to the lowest odd level on each line,
1316     // reverse any contiguous sequence of characters that are at that level or higher.
1317
1318     // Reversing the reordering of the line is only done up to the lowest odd level.
1319     if (!(minLevel % 2))
1320         ++minLevel;
1321
1322     Vector<InlineBox*>::iterator end = leafBoxesInLogicalOrder.end();
1323     while (minLevel <= maxLevel) {
1324         Vector<InlineBox*>::iterator it = leafBoxesInLogicalOrder.begin();
1325         while (it != end) {
1326             while (it != end) {
1327                 if ((*it)->bidiLevel() >= minLevel)
1328                     break;
1329                 ++it;
1330             }
1331             Vector<InlineBox*>::iterator first = it;
1332             while (it != end) {
1333                 if ((*it)->bidiLevel() < minLevel)
1334                     break;
1335                 ++it;
1336             }
1337             Vector<InlineBox*>::iterator last = it;
1338             if (customReverseImplementation) {
1339                 ASSERT(userData);
1340                 (*customReverseImplementation)(userData, first, last);
1341             } else
1342                 std::reverse(first, last);
1343         }
1344         ++minLevel;
1345     }
1346 }
1347
1348 #ifndef NDEBUG
1349
1350 const char* InlineFlowBox::boxName() const
1351 {
1352     return "InlineFlowBox";
1353 }
1354
1355 void InlineFlowBox::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj, int depth) const
1356 {
1357     InlineBox::showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, depth);
1358     for (const InlineBox* box = firstChild(); box; box = box->nextOnLine())
1359         box->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, depth + 1);
1360 }
1361
1362 #endif
1363
1364 #if ENABLE(ASSERT)
1365 void InlineFlowBox::checkConsistency() const
1366 {
1367 #ifdef CHECK_CONSISTENCY
1368     ASSERT(!m_hasBadChildList);
1369     const InlineBox* prev = 0;
1370     for (const InlineBox* child = m_firstChild; child; child = child->nextOnLine()) {
1371         ASSERT(child->parent() == this);
1372         ASSERT(child->prevOnLine() == prev);
1373         prev = child;
1374     }
1375     ASSERT(prev == m_lastChild);
1376 #endif
1377 }
1378
1379 #endif
1380
1381 } // namespace blink