Source/WebCore/rendering/RenderGrid.cpp

   1 /*
   2  * Copyright (C) 2011 Apple Inc. All rights reserved.
   3  * Copyright (C) 2013, 2014 Igalia S.L.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "config.h"
  28 #include "RenderGrid.h"
  29
  30 #if ENABLE(CSS_GRID_LAYOUT)
  31
  32 #include "GridCoordinate.h"
  33 #include "GridResolvedPosition.h"
  34 #include "LayoutRepainter.h"
  35 #include "RenderLayer.h"
  36 #include "RenderView.h"
  37 #include <wtf/NeverDestroyed.h>
  38
  39 namespace WebCore {
  40
  41 static const int infinity = -1;
  42
  43 class GridTrack {
  44 public:
  45     GridTrack()
  46         : m_usedBreadth(0)
  47         , m_maxBreadth(0)
  48     {
  49     }
  50
  51     void growUsedBreadth(LayoutUnit growth)
  52     {
  53         ASSERT(growth >= 0);
  54         m_usedBreadth += growth;
  55     }
  56     LayoutUnit usedBreadth() const { return m_usedBreadth; }
  57
  58     void growMaxBreadth(LayoutUnit growth)
  59     {
  60         if (m_maxBreadth == infinity)
  61             m_maxBreadth = m_usedBreadth + growth;
  62         else
  63             m_maxBreadth += growth;
  64     }
  65     LayoutUnit maxBreadthIfNotInfinite() const
  66     {
  67         return (m_maxBreadth == infinity) ? m_usedBreadth : m_maxBreadth;
  68     }
  69
  70     LayoutUnit m_usedBreadth;
  71     LayoutUnit m_maxBreadth;
  72 };
  73
  74 struct GridTrackForNormalization {
  75     GridTrackForNormalization(const GridTrack& track, double flex)
  76         : m_track(&track)
  77         , m_flex(flex)
  78         , m_normalizedFlexValue(track.m_usedBreadth / flex)
  79     {
  80     }
  81
  82     const GridTrack* m_track;
  83     double m_flex;
  84     LayoutUnit m_normalizedFlexValue;
  85 };
  86
  87 class RenderGrid::GridIterator {
  88     WTF_MAKE_NONCOPYABLE(GridIterator);
  89 public:
  90     // |direction| is the direction that is fixed to |fixedTrackIndex| so e.g
  91     // GridIterator(m_grid, ForColumns, 1) will walk over the rows of the 2nd column.
  92     GridIterator(const Vector<Vector<Vector<RenderBox*, 1>>>& grid, GridTrackSizingDirection direction, size_t fixedTrackIndex, size_t varyingTrackIndex = 0)
  93         : m_grid(grid)
  94         , m_direction(direction)
  95         , m_rowIndex((direction == ForColumns) ? varyingTrackIndex : fixedTrackIndex)
  96         , m_columnIndex((direction == ForColumns) ? fixedTrackIndex : varyingTrackIndex)
  97         , m_childIndex(0)
  98     {
  99         ASSERT(m_rowIndex < m_grid.size());
 100         ASSERT(m_columnIndex < m_grid[0].size());
 101     }
 102
 103     RenderBox* nextGridItem()
 104     {
 105         if (!m_grid.size())
 106             return 0;
 107
 108         size_t& varyingTrackIndex = (m_direction == ForColumns) ? m_rowIndex : m_columnIndex;
 109         const size_t endOfVaryingTrackIndex = (m_direction == ForColumns) ? m_grid.size() : m_grid[0].size();
 110         for (; varyingTrackIndex < endOfVaryingTrackIndex; ++varyingTrackIndex) {
 111             const Vector<RenderBox*>& children = m_grid[m_rowIndex][m_columnIndex];
 112             if (m_childIndex < children.size())
 113                 return children[m_childIndex++];
 114
 115             m_childIndex = 0;
 116         }
 117         return 0;
 118     }
 119
 120     bool isEmptyAreaEnough(size_t rowSpan, size_t columnSpan) const
 121     {
 122         // Ignore cells outside current grid as we will grow it later if needed.
 123         size_t maxRows = std::min(m_rowIndex + rowSpan, m_grid.size());
 124         size_t maxColumns = std::min(m_columnIndex + columnSpan, m_grid[0].size());
 125
 126         // This adds a O(N^2) behavior that shouldn't be a big deal as we expect spanning areas to be small.
 127         for (size_t row = m_rowIndex; row < maxRows; ++row) {
 128             for (size_t column = m_columnIndex; column < maxColumns; ++column) {
 129                 const Vector<RenderBox*>& children = m_grid[row][column];
 130                 if (!children.isEmpty())
 131                     return false;
 132             }
 133         }
 134
 135         return true;
 136     }
 137
 138     std::unique_ptr<GridCoordinate> nextEmptyGridArea(size_t fixedTrackSpan, size_t varyingTrackSpan)
 139     {
 140         ASSERT(fixedTrackSpan >= 1 && varyingTrackSpan >= 1);
 141
 142         if (m_grid.isEmpty())
 143             return nullptr;
 144
 145         size_t rowSpan = (m_direction == ForColumns) ? varyingTrackSpan : fixedTrackSpan;
 146         size_t columnSpan = (m_direction == ForColumns) ? fixedTrackSpan : varyingTrackSpan;
 147
 148         size_t& varyingTrackIndex = (m_direction == ForColumns) ? m_rowIndex : m_columnIndex;
 149         const size_t endOfVaryingTrackIndex = (m_direction == ForColumns) ? m_grid.size() : m_grid[0].size();
 150         for (; varyingTrackIndex < endOfVaryingTrackIndex; ++varyingTrackIndex) {
 151             if (isEmptyAreaEnough(rowSpan, columnSpan)) {
 152                 std::unique_ptr<GridCoordinate> result = std::make_unique<GridCoordinate>(GridSpan(m_rowIndex, m_rowIndex + rowSpan - 1), GridSpan(m_columnIndex, m_columnIndex + columnSpan - 1));
 153                 // Advance the iterator to avoid an infinite loop where we would return the same grid area over and over.
 154                 ++varyingTrackIndex;
 155                 return result;
 156             }
 157         }
 158         return nullptr;
 159     }
 160
 161 private:
 162     const Vector<Vector<Vector<RenderBox*, 1>>>& m_grid;
 163     GridTrackSizingDirection m_direction;
 164     size_t m_rowIndex;
 165     size_t m_columnIndex;
 166     size_t m_childIndex;
 167 };
 168
 169 class RenderGrid::GridSizingData {
 170     WTF_MAKE_NONCOPYABLE(GridSizingData);
 171 public:
 172     GridSizingData(size_t gridColumnCount, size_t gridRowCount)
 173         : columnTracks(gridColumnCount)
 174         , rowTracks(gridRowCount)
 175     {
 176     }
 177
 178     Vector<GridTrack> columnTracks;
 179     Vector<GridTrack> rowTracks;
 180     Vector<size_t> contentSizedTracksIndex;
 181
 182     // Performance optimization: hold onto these Vectors until the end of Layout to avoid repeated malloc / free.
 183     Vector<LayoutUnit> distributeTrackVector;
 184     Vector<GridTrack*> filteredTracks;
 185 };
 186
 187 RenderGrid::RenderGrid(Element& element, PassRef<RenderStyle> style)
 188     : RenderBlock(element, WTF::move(style), 0)
 189     , m_orderIterator(*this)
 190 {
 191     // All of our children must be block level.
 192     setChildrenInline(false);
 193 }
 194
 195 RenderGrid::~RenderGrid()
 196 {
 197 }
 198
 199 void RenderGrid::layoutBlock(bool relayoutChildren, LayoutUnit)
 200 {
 201     ASSERT(needsLayout());
 202
 203     if (!relayoutChildren && simplifiedLayout())
 204         return;
 205
 206     // FIXME: Much of this method is boiler plate that matches RenderBox::layoutBlock and Render*FlexibleBox::layoutBlock.
 207     // It would be nice to refactor some of the duplicate code.
 208     LayoutRepainter repainter(*this, checkForRepaintDuringLayout());
 209     LayoutStateMaintainer statePusher(view(), *this, locationOffset(), hasTransform() || hasReflection() || style().isFlippedBlocksWritingMode());
 210
 211     preparePaginationBeforeBlockLayout(relayoutChildren);
 212
 213     LayoutSize previousSize = size();
 214
 215     setLogicalHeight(0);
 216     updateLogicalWidth();
 217
 218     layoutGridItems();
 219
 220     LayoutUnit oldClientAfterEdge = clientLogicalBottom();
 221     updateLogicalHeight();
 222
 223     if (size() != previousSize)
 224         relayoutChildren = true;
 225
 226     layoutPositionedObjects(relayoutChildren || isRoot());
 227
 228     computeOverflow(oldClientAfterEdge);
 229     statePusher.pop();
 230
 231     updateLayerTransform();
 232
 233     // Update our scroll information if we're overflow:auto/scroll/hidden now that we know if
 234     // we overflow or not.
 235     updateScrollInfoAfterLayout();
 236
 237     repainter.repaintAfterLayout();
 238
 239     clearNeedsLayout();
 240 }
 241
 242 void RenderGrid::computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const
 243 {
 244     const_cast<RenderGrid*>(this)->placeItemsOnGrid();
 245
 246     GridSizingData sizingData(gridColumnCount(), gridRowCount());
 247     LayoutUnit availableLogicalSpace = 0;
 248     const_cast<RenderGrid*>(this)->computeUsedBreadthOfGridTracks(ForColumns, sizingData, availableLogicalSpace);
 249
 250     for (size_t i = 0; i < sizingData.columnTracks.size(); ++i) {
 251         LayoutUnit minTrackBreadth = sizingData.columnTracks[i].m_usedBreadth;
 252         LayoutUnit maxTrackBreadth = sizingData.columnTracks[i].m_maxBreadth;
 253         maxTrackBreadth = std::max(maxTrackBreadth, minTrackBreadth);
 254
 255         minLogicalWidth += minTrackBreadth;
 256         maxLogicalWidth += maxTrackBreadth;
 257
 258         // FIXME: This should add in the scrollbarWidth (e.g. see RenderFlexibleBox).
 259     }
 260
 261     const_cast<RenderGrid*>(this)->clearGrid();
 262 }
 263
 264 void RenderGrid::computePreferredLogicalWidths()
 265 {
 266     ASSERT(preferredLogicalWidthsDirty());
 267
 268     m_minPreferredLogicalWidth = 0;
 269     m_maxPreferredLogicalWidth = 0;
 270
 271     // FIXME: We don't take our own logical width into account. Once we do, we need to make sure
 272     // we apply (and test the interaction with) min-width / max-width.
 273
 274     computeIntrinsicLogicalWidths(m_minPreferredLogicalWidth, m_maxPreferredLogicalWidth);
 275
 276     LayoutUnit borderAndPaddingInInlineDirection = borderAndPaddingLogicalWidth();
 277     m_minPreferredLogicalWidth += borderAndPaddingInInlineDirection;
 278     m_maxPreferredLogicalWidth += borderAndPaddingInInlineDirection;
 279
 280     setPreferredLogicalWidthsDirty(false);
 281 }
 282
 283 void RenderGrid::computeUsedBreadthOfGridTracks(GridTrackSizingDirection direction, GridSizingData& sizingData)
 284 {
 285     LayoutUnit availableLogicalSpace = (direction == ForColumns) ? availableLogicalWidth() : availableLogicalHeight(IncludeMarginBorderPadding);
 286     computeUsedBreadthOfGridTracks(direction, sizingData, availableLogicalSpace);
 287 }
 288
 289 bool RenderGrid::gridElementIsShrinkToFit()
 290 {
 291     return isFloatingOrOutOfFlowPositioned();
 292 }
 293
 294 void RenderGrid::computeUsedBreadthOfGridTracks(GridTrackSizingDirection direction, GridSizingData& sizingData, LayoutUnit& availableLogicalSpace)
 295 {
 296     Vector<GridTrack>& tracks = (direction == ForColumns) ? sizingData.columnTracks : sizingData.rowTracks;
 297     Vector<size_t> flexibleSizedTracksIndex;
 298     sizingData.contentSizedTracksIndex.shrink(0);
 299
 300     // 1. Initialize per Grid track variables.
 301     for (size_t i = 0; i < tracks.size(); ++i) {
 302         GridTrack& track = tracks[i];
 303         const GridTrackSize& trackSize = gridTrackSize(direction, i);
 304         const GridLength& minTrackBreadth = trackSize.minTrackBreadth();
 305         const GridLength& maxTrackBreadth = trackSize.maxTrackBreadth();
 306
 307         track.m_usedBreadth = computeUsedBreadthOfMinLength(direction, minTrackBreadth);
 308         track.m_maxBreadth = computeUsedBreadthOfMaxLength(direction, maxTrackBreadth, track.m_usedBreadth);
 309
 310         track.m_maxBreadth = std::max(track.m_maxBreadth, track.m_usedBreadth);
 311
 312         if (trackSize.isContentSized())
 313             sizingData.contentSizedTracksIndex.append(i);
 314         if (trackSize.maxTrackBreadth().isFlex())
 315             flexibleSizedTracksIndex.append(i);
 316     }
 317
 318     // 2. Resolve content-based TrackSizingFunctions.
 319     if (!sizingData.contentSizedTracksIndex.isEmpty())
 320         resolveContentBasedTrackSizingFunctions(direction, sizingData);
 321
 322     for (size_t i = 0; i < tracks.size(); ++i) {
 323         ASSERT(tracks[i].m_maxBreadth != infinity);
 324         availableLogicalSpace -= tracks[i].m_usedBreadth;
 325     }
 326
 327     const bool hasUndefinedRemainingSpace = (direction == ForRows) ? style().logicalHeight().isAuto() : gridElementIsShrinkToFit();
 328
 329     if (!hasUndefinedRemainingSpace && availableLogicalSpace <= 0)
 330         return;
 331
 332     // 3. Grow all Grid tracks in GridTracks from their UsedBreadth up to their MaxBreadth value until
 333     // availableLogicalSpace (RemainingSpace in the specs) is exhausted.
 334     const size_t tracksSize = tracks.size();
 335     if (!hasUndefinedRemainingSpace) {
 336         Vector<GridTrack*> tracksForDistribution(tracksSize);
 337         for (size_t i = 0; i < tracksSize; ++i)
 338             tracksForDistribution[i] = tracks.data() + i;
 339
 340         distributeSpaceToTracks(tracksForDistribution, 0, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth, sizingData, availableLogicalSpace);
 341     } else {
 342         for (size_t i = 0; i < tracksSize; ++i)
 343             tracks[i].m_usedBreadth = tracks[i].m_maxBreadth;
 344     }
 345
 346     if (flexibleSizedTracksIndex.isEmpty())
 347         return;
 348
 349     // 4. Grow all Grid tracks having a fraction as the MaxTrackSizingFunction.
 350     double normalizedFractionBreadth = 0;
 351     if (!hasUndefinedRemainingSpace)
 352         normalizedFractionBreadth = computeNormalizedFractionBreadth(tracks, GridSpan(0, tracks.size() - 1), direction, availableLogicalSpace);
 353     else {
 354         for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
 355             const size_t trackIndex = flexibleSizedTracksIndex[i];
 356             const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
 357             normalizedFractionBreadth = std::max(normalizedFractionBreadth, tracks[trackIndex].m_usedBreadth / trackSize.maxTrackBreadth().flex());
 358         }
 359
 360         for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
 361             GridIterator iterator(m_grid, direction, flexibleSizedTracksIndex[i]);
 362             while (RenderBox* gridItem = iterator.nextGridItem()) {
 363                 const GridCoordinate coordinate = cachedGridCoordinate(gridItem);
 364                 const GridSpan span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
 365
 366                 // Do not include already processed items.
 367                 if (i > 0 && span.resolvedInitialPosition.toInt() <= flexibleSizedTracksIndex[i - 1])
 368                     continue;
 369
 370                 double itemNormalizedFlexBreadth = computeNormalizedFractionBreadth(tracks, span, direction, maxContentForChild(gridItem, direction, sizingData.columnTracks));
 371                 normalizedFractionBreadth = std::max(normalizedFractionBreadth, itemNormalizedFlexBreadth);
 372             }
 373         }
 374     }
 375
 376     for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
 377         const size_t trackIndex = flexibleSizedTracksIndex[i];
 378         const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
 379
 380         tracks[trackIndex].m_usedBreadth = std::max<LayoutUnit>(tracks[trackIndex].m_usedBreadth, normalizedFractionBreadth * trackSize.maxTrackBreadth().flex());
 381     }
 382 }
 383
 384 LayoutUnit RenderGrid::computeUsedBreadthOfMinLength(GridTrackSizingDirection direction, const GridLength& gridLength) const
 385 {
 386     if (gridLength.isFlex())
 387         return 0;
 388
 389     const Length& trackLength = gridLength.length();
 390     ASSERT(!trackLength.isAuto());
 391     if (trackLength.isSpecified())
 392         return computeUsedBreadthOfSpecifiedLength(direction, trackLength);
 393
 394     ASSERT(trackLength.isMinContent() || trackLength.isMaxContent());
 395     return 0;
 396 }
 397
 398 LayoutUnit RenderGrid::computeUsedBreadthOfMaxLength(GridTrackSizingDirection direction, const GridLength& gridLength, LayoutUnit usedBreadth) const
 399 {
 400     if (gridLength.isFlex())
 401         return usedBreadth;
 402
 403     const Length& trackLength = gridLength.length();
 404     ASSERT(!trackLength.isAuto());
 405     if (trackLength.isSpecified()) {
 406         LayoutUnit computedBreadth = computeUsedBreadthOfSpecifiedLength(direction, trackLength);
 407         ASSERT(computedBreadth != infinity);
 408         return computedBreadth;
 409     }
 410
 411     ASSERT(trackLength.isMinContent() || trackLength.isMaxContent());
 412     return infinity;
 413 }
 414
 415 LayoutUnit RenderGrid::computeUsedBreadthOfSpecifiedLength(GridTrackSizingDirection direction, const Length& trackLength) const
 416 {
 417     ASSERT(trackLength.isSpecified());
 418     return valueForLength(trackLength, direction == ForColumns ? logicalWidth() : computeContentLogicalHeight(style().logicalHeight()));
 419 }
 420
 421 double RenderGrid::computeNormalizedFractionBreadth(Vector<GridTrack>& tracks, const GridSpan& tracksSpan, GridTrackSizingDirection direction, LayoutUnit availableLogicalSpace) const
 422 {
 423     // |availableLogicalSpace| already accounts for the used breadths so no need to remove it here.
 424
 425     Vector<GridTrackForNormalization> tracksForNormalization;
 426     for (auto position : tracksSpan) {
 427         const GridTrackSize& trackSize = gridTrackSize(direction, position.toInt());
 428         if (!trackSize.maxTrackBreadth().isFlex())
 429             continue;
 430
 431         tracksForNormalization.append(GridTrackForNormalization(tracks[position.toInt()], trackSize.maxTrackBreadth().flex()));
 432     }
 433
 434     // The function is not called if we don't have <flex> grid tracks
 435     ASSERT(!tracksForNormalization.isEmpty());
 436
 437     std::sort(tracksForNormalization.begin(), tracksForNormalization.end(),
 438               [](const GridTrackForNormalization& track1, const GridTrackForNormalization& track2) {
 439                   return track1.m_normalizedFlexValue < track2.m_normalizedFlexValue;
 440               });
 441
 442     // These values work together: as we walk over our grid tracks, we increase fractionValueBasedOnGridItemsRatio
 443     // to match a grid track's usedBreadth to <flex> ratio until the total fractions sized grid tracks wouldn't
 444     // fit into availableLogicalSpaceIgnoringFractionTracks.
 445     double accumulatedFractions = 0;
 446     LayoutUnit fractionValueBasedOnGridItemsRatio = 0;
 447     LayoutUnit availableLogicalSpaceIgnoringFractionTracks = availableLogicalSpace;
 448
 449     for (size_t i = 0; i < tracksForNormalization.size(); ++i) {
 450         const GridTrackForNormalization& track = tracksForNormalization[i];
 451         if (track.m_normalizedFlexValue > fractionValueBasedOnGridItemsRatio) {
 452             // If the normalized flex value (we ordered |tracksForNormalization| by increasing normalized flex value)
 453             // will make us overflow our container, then stop. We have the previous step's ratio is the best fit.
 454             if (track.m_normalizedFlexValue * accumulatedFractions > availableLogicalSpaceIgnoringFractionTracks)
 455                 break;
 456
 457             fractionValueBasedOnGridItemsRatio = track.m_normalizedFlexValue;
 458         }
 459
 460         accumulatedFractions += track.m_flex;
 461         // This item was processed so we re-add its used breadth to the available space to accurately count the remaining space.
 462         availableLogicalSpaceIgnoringFractionTracks += track.m_track->m_usedBreadth;
 463     }
 464
 465     return availableLogicalSpaceIgnoringFractionTracks / accumulatedFractions;
 466 }
 467
 468 const GridTrackSize& RenderGrid::gridTrackSize(GridTrackSizingDirection direction, size_t i) const
 469 {
 470     const Vector<GridTrackSize>& trackStyles = (direction == ForColumns) ? style().gridColumns() : style().gridRows();
 471     if (i >= trackStyles.size())
 472         return (direction == ForColumns) ? style().gridAutoColumns() : style().gridAutoRows();
 473
 474     const GridTrackSize& trackSize = trackStyles[i];
 475     // If the logical width/height of the grid container is indefinite, percentage values are treated as <auto>.
 476     if (trackSize.isPercentage()) {
 477         Length logicalSize = direction == ForColumns ? style().logicalWidth() : style().logicalHeight();
 478         if (logicalSize.isIntrinsicOrAuto()) {
 479             static NeverDestroyed<GridTrackSize> autoTrackSize(Auto);
 480             return autoTrackSize.get();
 481         }
 482     }
 483
 484     return trackSize;
 485 }
 486
 487 LayoutUnit RenderGrid::logicalContentHeightForChild(RenderBox* child, Vector<GridTrack>& columnTracks)
 488 {
 489     LayoutUnit oldOverrideContainingBlockContentLogicalWidth = child->hasOverrideContainingBlockLogicalWidth() ? child->overrideContainingBlockContentLogicalWidth() : LayoutUnit();
 490     LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(child, ForColumns, columnTracks);
 491     if (child->style().logicalHeight().isPercent() || oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth)
 492         child->setNeedsLayout(MarkOnlyThis);
 493
 494     child->setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
 495     // If |child| has a percentage logical height, we shouldn't let it override its intrinsic height, which is
 496     // what we are interested in here. Thus we need to set the override logical height to -1 (no possible resolution).
 497     child->setOverrideContainingBlockContentLogicalHeight(-1);
 498     child->layoutIfNeeded();
 499     return child->logicalHeight() + child->marginLogicalHeight();
 500 }
 501
 502 LayoutUnit RenderGrid::minContentForChild(RenderBox* child, GridTrackSizingDirection direction, Vector<GridTrack>& columnTracks)
 503 {
 504     bool hasOrthogonalWritingMode = child->isHorizontalWritingMode() != isHorizontalWritingMode();
 505     // FIXME: Properly support orthogonal writing mode.
 506     if (hasOrthogonalWritingMode)
 507         return 0;
 508
 509     if (direction == ForColumns) {
 510         // FIXME: It's unclear if we should return the intrinsic width or the preferred width.
 511         // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
 512         return child->minPreferredLogicalWidth() + marginIntrinsicLogicalWidthForChild(*child);
 513     }
 514
 515     return logicalContentHeightForChild(child, columnTracks);
 516 }
 517
 518 LayoutUnit RenderGrid::maxContentForChild(RenderBox* child, GridTrackSizingDirection direction, Vector<GridTrack>& columnTracks)
 519 {
 520     bool hasOrthogonalWritingMode = child->isHorizontalWritingMode() != isHorizontalWritingMode();
 521     // FIXME: Properly support orthogonal writing mode.
 522     if (hasOrthogonalWritingMode)
 523         return LayoutUnit();
 524
 525     if (direction == ForColumns) {
 526         // FIXME: It's unclear if we should return the intrinsic width or the preferred width.
 527         // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
 528         return child->maxPreferredLogicalWidth() + marginIntrinsicLogicalWidthForChild(*child);
 529     }
 530
 531     return logicalContentHeightForChild(child, columnTracks);
 532 }
 533
 534 void RenderGrid::resolveContentBasedTrackSizingFunctions(GridTrackSizingDirection direction, GridSizingData& sizingData)
 535 {
 536     // FIXME: Split the grid tracks into groups that doesn't overlap a <flex> grid track.
 537
 538     for (size_t i = 0; i < sizingData.contentSizedTracksIndex.size(); ++i) {
 539         GridIterator iterator(m_grid, direction, sizingData.contentSizedTracksIndex[i]);
 540         while (RenderBox* gridItem = iterator.nextGridItem()) {
 541             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMinOrMaxContentMinTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth);
 542             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMaxContentMinTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth);
 543             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMinOrMaxContentMaxTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::maxBreadthIfNotInfinite, &GridTrack::growMaxBreadth);
 544             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMaxContentMaxTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::maxBreadthIfNotInfinite, &GridTrack::growMaxBreadth);
 545         }
 546
 547         GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[i] : sizingData.rowTracks[i];
 548         if (track.m_maxBreadth == infinity)
 549             track.m_maxBreadth = track.m_usedBreadth;
 550     }
 551 }
 552
 553 void RenderGrid::resolveContentBasedTrackSizingFunctionsForItems(GridTrackSizingDirection direction, GridSizingData& sizingData, RenderBox* gridItem, FilterFunction filterFunction, SizingFunction sizingFunction, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction)
 554 {
 555     const GridCoordinate coordinate = cachedGridCoordinate(gridItem);
 556     const GridResolvedPosition initialTrackPosition = (direction == ForColumns) ? coordinate.columns.resolvedInitialPosition : coordinate.rows.resolvedInitialPosition;
 557     const GridResolvedPosition finalTrackPosition = (direction == ForColumns) ? coordinate.columns.resolvedFinalPosition : coordinate.rows.resolvedFinalPosition;
 558
 559     sizingData.filteredTracks.shrink(0);
 560     for (GridResolvedPosition trackIndex = initialTrackPosition; trackIndex <= finalTrackPosition; ++trackIndex) {
 561         const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex.toInt());
 562         if (!(trackSize.*filterFunction)())
 563             continue;
 564
 565         GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackIndex.toInt()] : sizingData.rowTracks[trackIndex.toInt()];
 566         sizingData.filteredTracks.append(&track);
 567     }
 568
 569     if (sizingData.filteredTracks.isEmpty())
 570         return;
 571
 572     LayoutUnit additionalBreadthSpace = (this->*sizingFunction)(gridItem, direction, sizingData.columnTracks);
 573     for (GridResolvedPosition trackPositionForSpace = initialTrackPosition; trackPositionForSpace <= finalTrackPosition; ++trackPositionForSpace) {
 574         GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackPositionForSpace.toInt()] : sizingData.rowTracks[trackPositionForSpace.toInt()];
 575         additionalBreadthSpace -= (track.*trackGetter)();
 576     }
 577
 578     // FIXME: We should pass different values for |tracksForGrowthAboveMaxBreadth|.
 579     distributeSpaceToTracks(sizingData.filteredTracks, &sizingData.filteredTracks, trackGetter, trackGrowthFunction, sizingData, additionalBreadthSpace);
 580 }
 581
 582 static bool sortByGridTrackGrowthPotential(const GridTrack* track1, const GridTrack* track2)
 583 {
 584     return (track1->m_maxBreadth - track1->m_usedBreadth) < (track2->m_maxBreadth - track2->m_usedBreadth);
 585 }
 586
 587 void RenderGrid::distributeSpaceToTracks(Vector<GridTrack*>& tracks, Vector<GridTrack*>* tracksForGrowthAboveMaxBreadth, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction, GridSizingData& sizingData, LayoutUnit& availableLogicalSpace)
 588 {
 589     std::sort(tracks.begin(), tracks.end(), sortByGridTrackGrowthPotential);
 590
 591     size_t tracksSize = tracks.size();
 592     sizingData.distributeTrackVector.resize(tracksSize);
 593
 594     for (size_t i = 0; i < tracksSize; ++i) {
 595         GridTrack& track = *tracks[i];
 596         LayoutUnit availableLogicalSpaceShare = availableLogicalSpace / (tracksSize - i);
 597         LayoutUnit trackBreadth = (tracks[i]->*trackGetter)();
 598         LayoutUnit growthShare = std::max(LayoutUnit(), std::min(availableLogicalSpaceShare, track.m_maxBreadth - trackBreadth));
 599         // We should never shrink any grid track or else we can't guarantee we abide by our min-sizing function.
 600         sizingData.distributeTrackVector[i] = trackBreadth + growthShare;
 601         availableLogicalSpace -= growthShare;
 602     }
 603
 604     if (availableLogicalSpace > 0 && tracksForGrowthAboveMaxBreadth) {
 605         tracksSize = tracksForGrowthAboveMaxBreadth->size();
 606         for (size_t i = 0; i < tracksSize; ++i) {
 607             LayoutUnit growthShare = availableLogicalSpace / (tracksSize - i);
 608             sizingData.distributeTrackVector[i] += growthShare;
 609             availableLogicalSpace -= growthShare;
 610         }
 611     }
 612
 613     for (size_t i = 0; i < tracksSize; ++i) {
 614         LayoutUnit growth = sizingData.distributeTrackVector[i] - (tracks[i]->*trackGetter)();
 615         if (growth >= 0)
 616             (tracks[i]->*trackGrowthFunction)(growth);
 617     }
 618 }
 619
 620 #ifndef NDEBUG
 621 bool RenderGrid::tracksAreWiderThanMinTrackBreadth(GridTrackSizingDirection direction, const Vector<GridTrack>& tracks)
 622 {
 623     for (size_t i = 0; i < tracks.size(); ++i) {
 624         const GridTrackSize& trackSize = gridTrackSize(direction, i);
 625         const GridLength& minTrackBreadth = trackSize.minTrackBreadth();
 626         if (computeUsedBreadthOfMinLength(direction, minTrackBreadth) > tracks[i].m_usedBreadth)
 627             return false;
 628     }
 629     return true;
 630 }
 631 #endif
 632
 633 void RenderGrid::ensureGridSize(size_t maximumRowIndex, size_t maximumColumnIndex)
 634 {
 635     const size_t oldRowCount = gridRowCount();
 636     if (maximumRowIndex >= oldRowCount) {
 637         m_grid.grow(maximumRowIndex + 1);
 638         for (size_t row = oldRowCount; row < gridRowCount(); ++row)
 639             m_grid[row].grow(gridColumnCount());
 640     }
 641
 642     if (maximumColumnIndex >= gridColumnCount()) {
 643         for (size_t row = 0; row < gridRowCount(); ++row)
 644             m_grid[row].grow(maximumColumnIndex + 1);
 645     }
 646 }
 647
 648 void RenderGrid::insertItemIntoGrid(RenderBox* child, const GridCoordinate& coordinate)
 649 {
 650     ensureGridSize(coordinate.rows.resolvedFinalPosition.toInt(), coordinate.columns.resolvedFinalPosition.toInt());
 651
 652     for (auto row : coordinate.rows) {
 653         for (auto column : coordinate.columns)
 654             m_grid[row.toInt()][column.toInt()].append(child);
 655     }
 656     m_gridItemCoordinate.set(child, coordinate);
 657 }
 658
 659 void RenderGrid::placeItemsOnGrid()
 660 {
 661     ASSERT(!gridWasPopulated());
 662     ASSERT(m_gridItemCoordinate.isEmpty());
 663
 664     populateExplicitGridAndOrderIterator();
 665
 666     Vector<RenderBox*> autoMajorAxisAutoGridItems;
 667     Vector<RenderBox*> specifiedMajorAxisAutoGridItems;
 668     for (RenderBox* child = m_orderIterator.first(); child; child = m_orderIterator.next()) {
 669         // FIXME: We never re-resolve positions if the grid is grown during auto-placement which may lead auto / <integer>
 670         // positions to not match the author's intent. The specification is unclear on what should be done in this case.
 671         std::unique_ptr<GridSpan> rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(style(), *child, ForRows);
 672         std::unique_ptr<GridSpan> columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(style(), *child, ForColumns);
 673         if (!rowPositions || !columnPositions) {
 674             GridSpan* majorAxisPositions = (autoPlacementMajorAxisDirection() == ForColumns) ? columnPositions.get() : rowPositions.get();
 675             if (!majorAxisPositions)
 676                 autoMajorAxisAutoGridItems.append(child);
 677             else
 678                 specifiedMajorAxisAutoGridItems.append(child);
 679             continue;
 680         }
 681         insertItemIntoGrid(child, GridCoordinate(*rowPositions, *columnPositions));
 682     }
 683
 684     ASSERT(gridRowCount() >= style().gridRows().size());
 685     ASSERT(gridColumnCount() >= style().gridColumns().size());
 686
 687     // FIXME: Implement properly "stack" value in auto-placement algorithm.
 688     if (style().isGridAutoFlowAlgorithmStack()) {
 689         // If we did collect some grid items, they won't be placed thus never laid out.
 690         ASSERT(!autoMajorAxisAutoGridItems.size());
 691         ASSERT(!specifiedMajorAxisAutoGridItems.size());
 692         return;
 693     }
 694
 695     placeSpecifiedMajorAxisItemsOnGrid(specifiedMajorAxisAutoGridItems);
 696     placeAutoMajorAxisItemsOnGrid(autoMajorAxisAutoGridItems);
 697 }
 698
 699 void RenderGrid::populateExplicitGridAndOrderIterator()
 700 {
 701     OrderIteratorPopulator populator(m_orderIterator);
 702     size_t maximumRowIndex = std::max<size_t>(1, style().gridRows().size());
 703     size_t maximumColumnIndex = std::max<size_t>(1, style().gridColumns().size());
 704
 705     for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
 706         populator.collectChild(*child);
 707
 708         // This function bypasses the cache (cachedGridCoordinate()) as it is used to build it.
 709         std::unique_ptr<GridSpan> rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(style(), *child, ForRows);
 710         std::unique_ptr<GridSpan> columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(style(), *child, ForColumns);
 711
 712         // |positions| is 0 if we need to run the auto-placement algorithm.
 713         if (rowPositions)
 714             maximumRowIndex = std::max(maximumRowIndex, rowPositions->resolvedFinalPosition.next().toInt());
 715         else {
 716             // Grow the grid for items with a definite row span, getting the largest such span.
 717             GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(style(), *child, ForRows, GridResolvedPosition(0));
 718             maximumRowIndex = std::max<size_t>(maximumRowIndex, positions.resolvedFinalPosition.next().toInt());
 719         }
 720
 721         if (columnPositions)
 722             maximumColumnIndex = std::max(maximumColumnIndex, columnPositions->resolvedFinalPosition.next().toInt());
 723         else {
 724             // Grow the grid for items with a definite column span, getting the largest such span.
 725             GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(style(), *child, ForColumns, GridResolvedPosition(0));
 726             maximumColumnIndex = std::max<size_t>(maximumColumnIndex, positions.resolvedFinalPosition.next().toInt());
 727         }
 728     }
 729
 730     m_grid.grow(maximumRowIndex);
 731     for (size_t i = 0; i < m_grid.size(); ++i)
 732         m_grid[i].grow(maximumColumnIndex);
 733 }
 734
 735 std::unique_ptr<GridCoordinate> RenderGrid::createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(const RenderBox* gridItem, GridTrackSizingDirection specifiedDirection, const GridSpan& specifiedPositions) const
 736 {
 737     GridTrackSizingDirection crossDirection = specifiedDirection == ForColumns ? ForRows : ForColumns;
 738     const size_t endOfCrossDirection = crossDirection == ForColumns ? gridColumnCount() : gridRowCount();
 739     GridSpan crossDirectionPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(style(), *gridItem, crossDirection, GridResolvedPosition(endOfCrossDirection));
 740     return std::make_unique<GridCoordinate>(specifiedDirection == ForColumns ? crossDirectionPositions : specifiedPositions, specifiedDirection == ForColumns ? specifiedPositions : crossDirectionPositions);
 741 }
 742
 743 void RenderGrid::placeSpecifiedMajorAxisItemsOnGrid(const Vector<RenderBox*>& autoGridItems)
 744 {
 745     for (auto& autoGridItem : autoGridItems) {
 746         std::unique_ptr<GridSpan> majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(style(), *autoGridItem, autoPlacementMajorAxisDirection());
 747         GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(style(), *autoGridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
 748
 749         GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions->resolvedInitialPosition.toInt());
 750         std::unique_ptr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions->integerSpan(), minorAxisPositions.integerSpan());
 751         if (!emptyGridArea)
 752             emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(autoGridItem, autoPlacementMajorAxisDirection(), *majorAxisPositions);
 753         insertItemIntoGrid(autoGridItem, *emptyGridArea);
 754     }
 755 }
 756
 757 void RenderGrid::placeAutoMajorAxisItemsOnGrid(const Vector<RenderBox*>& autoGridItems)
 758 {
 759     AutoPlacementCursor autoPlacementCursor = {0, 0};
 760     bool isGridAutoFlowDense = style().isGridAutoFlowAlgorithmDense();
 761
 762     for (auto& autoGridItem : autoGridItems) {
 763         placeAutoMajorAxisItemOnGrid(autoGridItem, autoPlacementCursor);
 764
 765         if (isGridAutoFlowDense) {
 766             autoPlacementCursor.first = 0;
 767             autoPlacementCursor.second = 0;
 768         }
 769     }
 770 }
 771
 772 void RenderGrid::placeAutoMajorAxisItemOnGrid(RenderBox* gridItem,
 773 AutoPlacementCursor& autoPlacementCursor)
 774 {
 775     std::unique_ptr<GridSpan> minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(style(), *gridItem, autoPlacementMinorAxisDirection());
 776     ASSERT(!GridResolvedPosition::resolveGridPositionsFromStyle(style(), *gridItem, autoPlacementMajorAxisDirection()));
 777     GridSpan majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(style(), *gridItem, autoPlacementMajorAxisDirection(), GridResolvedPosition(0));
 778
 779     const size_t endOfMajorAxis = (autoPlacementMajorAxisDirection() == ForColumns) ? gridColumnCount() : gridRowCount();
 780     size_t majorAxisAutoPlacementCursor = autoPlacementMajorAxisDirection() == ForColumns ? autoPlacementCursor.second : autoPlacementCursor.first;
 781     size_t minorAxisAutoPlacementCursor = autoPlacementMajorAxisDirection() == ForColumns ? autoPlacementCursor.first : autoPlacementCursor.second;
 782
 783     std::unique_ptr<GridCoordinate> emptyGridArea;
 784     if (minorAxisPositions) {
 785         // Move to the next track in major axis if initial position in minor axis is before auto-placement cursor.
 786         if (minorAxisPositions->resolvedInitialPosition.toInt() < minorAxisAutoPlacementCursor)
 787             majorAxisAutoPlacementCursor++;
 788
 789         if (majorAxisAutoPlacementCursor < endOfMajorAxis) {
 790             GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisPositions->resolvedInitialPosition.toInt(), majorAxisAutoPlacementCursor);
 791             emptyGridArea = iterator.nextEmptyGridArea(minorAxisPositions->integerSpan(), majorAxisPositions.integerSpan());
 792         }
 793
 794         if (!emptyGridArea)
 795             emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), *minorAxisPositions);
 796     } else {
 797         GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(style(), *gridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
 798
 799         for (size_t majorAxisIndex = majorAxisAutoPlacementCursor; majorAxisIndex < endOfMajorAxis; ++majorAxisIndex) {
 800             GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisIndex, minorAxisAutoPlacementCursor);
 801             emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions.integerSpan(), minorAxisPositions.integerSpan());
 802
 803             if (emptyGridArea) {
 804                 // Check that it fits in the minor axis direction, as we shouldn't grow in that direction here (it was already managed in populateExplicitGridAndOrderIterator()).
 805                 GridResolvedPosition minorAxisFinalPositionIndex = autoPlacementMinorAxisDirection() == ForColumns ? emptyGridArea->columns.resolvedFinalPosition : emptyGridArea->rows.resolvedFinalPosition;
 806                 const size_t endOfMinorAxis = autoPlacementMinorAxisDirection() == ForColumns ? gridColumnCount() : gridRowCount();
 807                 if (minorAxisFinalPositionIndex.toInt() < endOfMinorAxis)
 808                     break;
 809
 810                 // Discard empty grid area as it does not fit in the minor axis direction.
 811                 // We don't need to create a new empty grid area yet as we might find a valid one in the next iteration.
 812                 emptyGridArea = nullptr;
 813             }
 814
 815             // As we're moving to the next track in the major axis we should reset the auto-placement cursor in the minor axis.
 816             minorAxisAutoPlacementCursor = 0;
 817         }
 818
 819         if (!emptyGridArea)
 820             emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), minorAxisPositions);
 821     }
 822
 823     insertItemIntoGrid(gridItem, *emptyGridArea);
 824     autoPlacementCursor.first = emptyGridArea->rows.resolvedInitialPosition.toInt();
 825     autoPlacementCursor.second = emptyGridArea->columns.resolvedInitialPosition.toInt();
 826 }
 827
 828 GridTrackSizingDirection RenderGrid::autoPlacementMajorAxisDirection() const
 829 {
 830     return style().isGridAutoFlowDirectionColumn() ? ForColumns : ForRows;
 831 }
 832
 833 GridTrackSizingDirection RenderGrid::autoPlacementMinorAxisDirection() const
 834 {
 835     return style().isGridAutoFlowDirectionColumn() ? ForRows : ForColumns;
 836 }
 837
 838 void RenderGrid::clearGrid()
 839 {
 840     m_grid.clear();
 841     m_gridItemCoordinate.clear();
 842 }
 843
 844 void RenderGrid::layoutGridItems()
 845 {
 846     placeItemsOnGrid();
 847
 848     GridSizingData sizingData(gridColumnCount(), gridRowCount());
 849     computeUsedBreadthOfGridTracks(ForColumns, sizingData);
 850     ASSERT(tracksAreWiderThanMinTrackBreadth(ForColumns, sizingData.columnTracks));
 851     computeUsedBreadthOfGridTracks(ForRows, sizingData);
 852     ASSERT(tracksAreWiderThanMinTrackBreadth(ForRows, sizingData.rowTracks));
 853
 854     populateGridPositions(sizingData);
 855
 856     for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
 857         // Because the grid area cannot be styled, we don't need to adjust
 858         // the grid breadth to account for 'box-sizing'.
 859         LayoutUnit oldOverrideContainingBlockContentLogicalWidth = child->hasOverrideContainingBlockLogicalWidth() ? child->overrideContainingBlockContentLogicalWidth() : LayoutUnit();
 860         LayoutUnit oldOverrideContainingBlockContentLogicalHeight = child->hasOverrideContainingBlockLogicalHeight() ? child->overrideContainingBlockContentLogicalHeight() : LayoutUnit();
 861
 862         LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(child, ForColumns, sizingData.columnTracks);
 863         LayoutUnit overrideContainingBlockContentLogicalHeight = gridAreaBreadthForChild(child, ForRows, sizingData.rowTracks);
 864         if (oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth || (oldOverrideContainingBlockContentLogicalHeight != overrideContainingBlockContentLogicalHeight && child->hasRelativeLogicalHeight()))
 865             child->setNeedsLayout(MarkOnlyThis);
 866
 867         child->setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
 868         child->setOverrideContainingBlockContentLogicalHeight(overrideContainingBlockContentLogicalHeight);
 869
 870         LayoutRect oldChildRect = child->frameRect();
 871
 872         // FIXME: Grid items should stretch to fill their cells. Once we
 873         // implement grid-{column,row}-align, we can also shrink to fit. For
 874         // now, just size as if we were a regular child.
 875         child->layoutIfNeeded();
 876
 877         child->setLogicalLocation(findChildLogicalPosition(child, sizingData));
 878
 879         // If the child moved, we have to repaint it as well as any floating/positioned
 880         // descendants. An exception is if we need a layout. In this case, we know we're going to
 881         // repaint ourselves (and the child) anyway.
 882         if (!selfNeedsLayout() && child->checkForRepaintDuringLayout())
 883             child->repaintDuringLayoutIfMoved(oldChildRect);
 884     }
 885
 886     for (size_t i = 0; i < sizingData.rowTracks.size(); ++i)
 887         setLogicalHeight(logicalHeight() + sizingData.rowTracks[i].m_usedBreadth);
 888
 889     // min / max logical height is handled in updateLogicalHeight().
 890     setLogicalHeight(logicalHeight() + borderAndPaddingLogicalHeight());
 891     clearGrid();
 892 }
 893
 894 GridCoordinate RenderGrid::cachedGridCoordinate(const RenderBox* gridItem) const
 895 {
 896     ASSERT(m_gridItemCoordinate.contains(gridItem));
 897     return m_gridItemCoordinate.get(gridItem);
 898 }
 899
 900 LayoutUnit RenderGrid::gridAreaBreadthForChild(const RenderBox* child, GridTrackSizingDirection direction, const Vector<GridTrack>& tracks) const
 901 {
 902     const GridCoordinate& coordinate = cachedGridCoordinate(child);
 903     const GridSpan& span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
 904     LayoutUnit gridAreaBreadth = 0;
 905     for (auto trackPosition : span)
 906         gridAreaBreadth += tracks[trackPosition.toInt()].m_usedBreadth;
 907     return gridAreaBreadth;
 908 }
 909
 910 void RenderGrid::populateGridPositions(const GridSizingData& sizingData)
 911 {
 912     m_columnPositions.resizeToFit(sizingData.columnTracks.size() + 1);
 913     m_columnPositions[0] = borderAndPaddingStart();
 914     for (size_t i = 0; i < m_columnPositions.size() - 1; ++i)
 915         m_columnPositions[i + 1] = m_columnPositions[i] + sizingData.columnTracks[i].m_usedBreadth;
 916
 917     m_rowPositions.resizeToFit(sizingData.rowTracks.size() + 1);
 918     m_rowPositions[0] = borderAndPaddingBefore();
 919     for (size_t i = 0; i < m_rowPositions.size() - 1; ++i)
 920         m_rowPositions[i + 1] = m_rowPositions[i] + sizingData.rowTracks[i].m_usedBreadth;
 921 }
 922
 923 LayoutPoint RenderGrid::findChildLogicalPosition(RenderBox* child, const GridSizingData& sizingData)
 924 {
 925     const GridCoordinate& coordinate = cachedGridCoordinate(child);
 926     ASSERT_UNUSED(sizingData, coordinate.columns.resolvedInitialPosition.toInt() < sizingData.columnTracks.size());
 927     ASSERT_UNUSED(sizingData, coordinate.rows.resolvedInitialPosition.toInt() < sizingData.rowTracks.size());
 928
 929     // The grid items should be inside the grid container's border box, that's why they need to be shifted.
 930     return LayoutPoint(m_columnPositions[coordinate.columns.resolvedInitialPosition.toInt()] + marginStartForChild(*child), m_rowPositions[coordinate.rows.resolvedInitialPosition.toInt()] + marginBeforeForChild(*child));
 931 }
 932
 933 void RenderGrid::paintChildren(PaintInfo& paintInfo, const LayoutPoint& paintOffset, PaintInfo& forChild, bool usePrintRect)
 934 {
 935     for (RenderBox* child = m_orderIterator.first(); child; child = m_orderIterator.next())
 936         paintChild(*child, paintInfo, paintOffset, forChild, usePrintRect);
 937 }
 938
 939 const char* RenderGrid::renderName() const
 940 {
 941     if (isFloating())
 942         return "RenderGrid (floating)";
 943     if (isOutOfFlowPositioned())
 944         return "RenderGrid (positioned)";
 945     if (isAnonymous())
 946         return "RenderGrid (generated)";
 947     if (isRelPositioned())
 948         return "RenderGrid (relative positioned)";
 949     return "RenderGrid";
 950 }
 951
 952 } // namespace WebCore
 953
 954 #endif /* ENABLE(CSS_GRID_LAYOUT) */