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 "LayoutRepainter.h"
  34 #include "RenderLayer.h"
  35 #include "RenderView.h"
  36 #include <wtf/NeverDestroyed.h>
  37
  38 namespace WebCore {
  39
  40 static const int infinity = -1;
  41
  42 class GridTrack {
  43 public:
  44     GridTrack()
  45         : m_usedBreadth(0)
  46         , m_maxBreadth(0)
  47     {
  48     }
  49
  50     void growUsedBreadth(LayoutUnit growth)
  51     {
  52         ASSERT(growth >= 0);
  53         m_usedBreadth += growth;
  54     }
  55     LayoutUnit usedBreadth() const { return m_usedBreadth; }
  56
  57     void growMaxBreadth(LayoutUnit growth)
  58     {
  59         if (m_maxBreadth == infinity)
  60             m_maxBreadth = m_usedBreadth + growth;
  61         else
  62             m_maxBreadth += growth;
  63     }
  64     LayoutUnit maxBreadthIfNotInfinite() const
  65     {
  66         return (m_maxBreadth == infinity) ? m_usedBreadth : m_maxBreadth;
  67     }
  68
  69     LayoutUnit m_usedBreadth;
  70     LayoutUnit m_maxBreadth;
  71 };
  72
  73 struct GridTrackForNormalization {
  74     GridTrackForNormalization(const GridTrack& track, double flex)
  75         : m_track(&track)
  76         , m_flex(flex)
  77         , m_normalizedFlexValue(track.m_usedBreadth / flex)
  78     {
  79     }
  80
  81     const GridTrack* m_track;
  82     double m_flex;
  83     LayoutUnit m_normalizedFlexValue;
  84 };
  85
  86 class RenderGrid::GridIterator {
  87     WTF_MAKE_NONCOPYABLE(GridIterator);
  88 public:
  89     // |direction| is the direction that is fixed to |fixedTrackIndex| so e.g
  90     // GridIterator(m_grid, ForColumns, 1) will walk over the rows of the 2nd column.
  91     GridIterator(const Vector<Vector<Vector<RenderBox*, 1>>>& grid, GridTrackSizingDirection direction, size_t fixedTrackIndex)
  92         : m_grid(grid)
  93         , m_direction(direction)
  94         , m_rowIndex((direction == ForColumns) ? 0 : fixedTrackIndex)
  95         , m_columnIndex((direction == ForColumns) ? fixedTrackIndex : 0)
  96         , m_childIndex(0)
  97     {
  98         ASSERT(m_rowIndex < m_grid.size());
  99         ASSERT(m_columnIndex < m_grid[0].size());
 100     }
 101
 102     RenderBox* nextGridItem()
 103     {
 104         if (!m_grid.size())
 105             return 0;
 106
 107         size_t& varyingTrackIndex = (m_direction == ForColumns) ? m_rowIndex : m_columnIndex;
 108         const size_t endOfVaryingTrackIndex = (m_direction == ForColumns) ? m_grid.size() : m_grid[0].size();
 109         for (; varyingTrackIndex < endOfVaryingTrackIndex; ++varyingTrackIndex) {
 110             const Vector<RenderBox*>& children = m_grid[m_rowIndex][m_columnIndex];
 111             if (m_childIndex < children.size())
 112                 return children[m_childIndex++];
 113
 114             m_childIndex = 0;
 115         }
 116         return 0;
 117     }
 118
 119     std::unique_ptr<GridCoordinate> nextEmptyGridArea()
 120     {
 121         if (m_grid.isEmpty())
 122             return nullptr;
 123
 124         size_t& varyingTrackIndex = (m_direction == ForColumns) ? m_rowIndex : m_columnIndex;
 125         const size_t endOfVaryingTrackIndex = (m_direction == ForColumns) ? m_grid.size() : m_grid[0].size();
 126         for (; varyingTrackIndex < endOfVaryingTrackIndex; ++varyingTrackIndex) {
 127             const Vector<RenderBox*>& children = m_grid[m_rowIndex][m_columnIndex];
 128             if (children.isEmpty()) {
 129                 std::unique_ptr<GridCoordinate> result = std::make_unique<GridCoordinate>(GridSpan(m_rowIndex, m_rowIndex), GridSpan(m_columnIndex, m_columnIndex));
 130                 // Advance the iterator to avoid an infinite loop where we would return the same grid area over and over.
 131                 ++varyingTrackIndex;
 132                 return result;
 133             }
 134         }
 135         return nullptr;
 136     }
 137
 138 private:
 139     const Vector<Vector<Vector<RenderBox*, 1>>>& m_grid;
 140     GridTrackSizingDirection m_direction;
 141     size_t m_rowIndex;
 142     size_t m_columnIndex;
 143     size_t m_childIndex;
 144 };
 145
 146 class RenderGrid::GridSizingData {
 147     WTF_MAKE_NONCOPYABLE(GridSizingData);
 148 public:
 149     GridSizingData(size_t gridColumnCount, size_t gridRowCount)
 150         : columnTracks(gridColumnCount)
 151         , rowTracks(gridRowCount)
 152     {
 153     }
 154
 155     Vector<GridTrack> columnTracks;
 156     Vector<GridTrack> rowTracks;
 157     Vector<size_t> contentSizedTracksIndex;
 158
 159     // Performance optimization: hold onto these Vectors until the end of Layout to avoid repeated malloc / free.
 160     Vector<LayoutUnit> distributeTrackVector;
 161     Vector<GridTrack*> filteredTracks;
 162 };
 163
 164 RenderGrid::RenderGrid(Element& element, PassRef<RenderStyle> style)
 165     : RenderBlock(element, std::move(style), 0)
 166     , m_orderIterator(*this)
 167 {
 168     // All of our children must be block level.
 169     setChildrenInline(false);
 170 }
 171
 172 RenderGrid::~RenderGrid()
 173 {
 174 }
 175
 176 void RenderGrid::layoutBlock(bool relayoutChildren, LayoutUnit)
 177 {
 178     ASSERT(needsLayout());
 179
 180     if (!relayoutChildren && simplifiedLayout())
 181         return;
 182
 183     // FIXME: Much of this method is boiler plate that matches RenderBox::layoutBlock and Render*FlexibleBox::layoutBlock.
 184     // It would be nice to refactor some of the duplicate code.
 185     LayoutRepainter repainter(*this, checkForRepaintDuringLayout());
 186     LayoutStateMaintainer statePusher(view(), *this, locationOffset(), hasTransform() || hasReflection() || style().isFlippedBlocksWritingMode());
 187
 188     preparePaginationBeforeBlockLayout(relayoutChildren);
 189
 190     LayoutSize previousSize = size();
 191
 192     setLogicalHeight(0);
 193     updateLogicalWidth();
 194
 195     layoutGridItems();
 196
 197     LayoutUnit oldClientAfterEdge = clientLogicalBottom();
 198     updateLogicalHeight();
 199
 200     if (size() != previousSize)
 201         relayoutChildren = true;
 202
 203     layoutPositionedObjects(relayoutChildren || isRoot());
 204
 205     computeOverflow(oldClientAfterEdge);
 206     statePusher.pop();
 207
 208     updateLayerTransform();
 209
 210     // Update our scroll information if we're overflow:auto/scroll/hidden now that we know if
 211     // we overflow or not.
 212     updateScrollInfoAfterLayout();
 213
 214     repainter.repaintAfterLayout();
 215
 216     clearNeedsLayout();
 217 }
 218
 219 void RenderGrid::computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const
 220 {
 221     const_cast<RenderGrid*>(this)->placeItemsOnGrid();
 222
 223     GridSizingData sizingData(gridColumnCount(), gridRowCount());
 224     LayoutUnit availableLogicalSpace = 0;
 225     const_cast<RenderGrid*>(this)->computeUsedBreadthOfGridTracks(ForColumns, sizingData, availableLogicalSpace);
 226
 227     for (size_t i = 0; i < sizingData.columnTracks.size(); ++i) {
 228         LayoutUnit minTrackBreadth = sizingData.columnTracks[i].m_usedBreadth;
 229         LayoutUnit maxTrackBreadth = sizingData.columnTracks[i].m_maxBreadth;
 230         maxTrackBreadth = std::max(maxTrackBreadth, minTrackBreadth);
 231
 232         minLogicalWidth += minTrackBreadth;
 233         maxLogicalWidth += maxTrackBreadth;
 234
 235         // FIXME: This should add in the scrollbarWidth (e.g. see RenderFlexibleBox).
 236     }
 237
 238     const_cast<RenderGrid*>(this)->clearGrid();
 239 }
 240
 241 void RenderGrid::computePreferredLogicalWidths()
 242 {
 243     ASSERT(preferredLogicalWidthsDirty());
 244
 245     m_minPreferredLogicalWidth = 0;
 246     m_maxPreferredLogicalWidth = 0;
 247
 248     // FIXME: We don't take our own logical width into account. Once we do, we need to make sure
 249     // we apply (and test the interaction with) min-width / max-width.
 250
 251     computeIntrinsicLogicalWidths(m_minPreferredLogicalWidth, m_maxPreferredLogicalWidth);
 252
 253     LayoutUnit borderAndPaddingInInlineDirection = borderAndPaddingLogicalWidth();
 254     m_minPreferredLogicalWidth += borderAndPaddingInInlineDirection;
 255     m_maxPreferredLogicalWidth += borderAndPaddingInInlineDirection;
 256
 257     setPreferredLogicalWidthsDirty(false);
 258 }
 259
 260 void RenderGrid::computeUsedBreadthOfGridTracks(GridTrackSizingDirection direction, GridSizingData& sizingData)
 261 {
 262     LayoutUnit availableLogicalSpace = (direction == ForColumns) ? availableLogicalWidth() : availableLogicalHeight(IncludeMarginBorderPadding);
 263     computeUsedBreadthOfGridTracks(direction, sizingData, availableLogicalSpace);
 264 }
 265
 266 bool RenderGrid::gridElementIsShrinkToFit()
 267 {
 268     return isFloatingOrOutOfFlowPositioned();
 269 }
 270
 271 void RenderGrid::computeUsedBreadthOfGridTracks(GridTrackSizingDirection direction, GridSizingData& sizingData, LayoutUnit& availableLogicalSpace)
 272 {
 273     Vector<GridTrack>& tracks = (direction == ForColumns) ? sizingData.columnTracks : sizingData.rowTracks;
 274     Vector<size_t> flexibleSizedTracksIndex;
 275     sizingData.contentSizedTracksIndex.shrink(0);
 276
 277     // 1. Initialize per Grid track variables.
 278     for (size_t i = 0; i < tracks.size(); ++i) {
 279         GridTrack& track = tracks[i];
 280         const GridTrackSize& trackSize = gridTrackSize(direction, i);
 281         const GridLength& minTrackBreadth = trackSize.minTrackBreadth();
 282         const GridLength& maxTrackBreadth = trackSize.maxTrackBreadth();
 283
 284         track.m_usedBreadth = computeUsedBreadthOfMinLength(direction, minTrackBreadth);
 285         track.m_maxBreadth = computeUsedBreadthOfMaxLength(direction, maxTrackBreadth, track.m_usedBreadth);
 286
 287         track.m_maxBreadth = std::max(track.m_maxBreadth, track.m_usedBreadth);
 288
 289         if (trackSize.isContentSized())
 290             sizingData.contentSizedTracksIndex.append(i);
 291         if (trackSize.maxTrackBreadth().isFlex())
 292             flexibleSizedTracksIndex.append(i);
 293     }
 294
 295     // 2. Resolve content-based TrackSizingFunctions.
 296     if (!sizingData.contentSizedTracksIndex.isEmpty())
 297         resolveContentBasedTrackSizingFunctions(direction, sizingData);
 298
 299     for (size_t i = 0; i < tracks.size(); ++i) {
 300         ASSERT(tracks[i].m_maxBreadth != infinity);
 301         availableLogicalSpace -= tracks[i].m_usedBreadth;
 302     }
 303
 304     const bool hasUndefinedRemainingSpace = (direction == ForRows) ? style().logicalHeight().isAuto() : gridElementIsShrinkToFit();
 305
 306     if (!hasUndefinedRemainingSpace && availableLogicalSpace <= 0)
 307         return;
 308
 309     // 3. Grow all Grid tracks in GridTracks from their UsedBreadth up to their MaxBreadth value until
 310     // availableLogicalSpace (RemainingSpace in the specs) is exhausted.
 311     const size_t tracksSize = tracks.size();
 312     if (!hasUndefinedRemainingSpace) {
 313         Vector<GridTrack*> tracksForDistribution(tracksSize);
 314         for (size_t i = 0; i < tracksSize; ++i)
 315             tracksForDistribution[i] = tracks.data() + i;
 316
 317         distributeSpaceToTracks(tracksForDistribution, 0, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth, sizingData, availableLogicalSpace);
 318     } else {
 319         for (size_t i = 0; i < tracksSize; ++i)
 320             tracks[i].m_usedBreadth = tracks[i].m_maxBreadth;
 321     }
 322
 323     if (flexibleSizedTracksIndex.isEmpty())
 324         return;
 325
 326     // 4. Grow all Grid tracks having a fraction as the MaxTrackSizingFunction.
 327     double normalizedFractionBreadth = 0;
 328     if (!hasUndefinedRemainingSpace)
 329         normalizedFractionBreadth = computeNormalizedFractionBreadth(tracks, GridSpan(0, tracks.size() - 1), direction, availableLogicalSpace);
 330     else {
 331         for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
 332             const size_t trackIndex = flexibleSizedTracksIndex[i];
 333             const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
 334             normalizedFractionBreadth = std::max(normalizedFractionBreadth, tracks[trackIndex].m_usedBreadth / trackSize.maxTrackBreadth().flex());
 335         }
 336
 337         for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
 338             GridIterator iterator(m_grid, direction, flexibleSizedTracksIndex[i]);
 339             while (RenderBox* gridItem = iterator.nextGridItem()) {
 340                 const GridCoordinate coordinate = cachedGridCoordinate(gridItem);
 341                 const GridSpan span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
 342
 343                 // Do not include already processed items.
 344                 if (i > 0 && span.initialPositionIndex <= flexibleSizedTracksIndex[i - 1])
 345                     continue;
 346
 347                 double itemNormalizedFlexBreadth = computeNormalizedFractionBreadth(tracks, span, direction, maxContentForChild(gridItem, direction, sizingData.columnTracks));
 348                 normalizedFractionBreadth = std::max(normalizedFractionBreadth, itemNormalizedFlexBreadth);
 349             }
 350         }
 351     }
 352
 353     for (size_t i = 0; i < flexibleSizedTracksIndex.size(); ++i) {
 354         const size_t trackIndex = flexibleSizedTracksIndex[i];
 355         const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
 356
 357         tracks[trackIndex].m_usedBreadth = std::max<LayoutUnit>(tracks[trackIndex].m_usedBreadth, normalizedFractionBreadth * trackSize.maxTrackBreadth().flex());
 358     }
 359 }
 360
 361 LayoutUnit RenderGrid::computeUsedBreadthOfMinLength(GridTrackSizingDirection direction, const GridLength& gridLength) const
 362 {
 363     if (gridLength.isFlex())
 364         return 0;
 365
 366     const Length& trackLength = gridLength.length();
 367     ASSERT(!trackLength.isAuto());
 368     if (trackLength.isSpecified())
 369         return computeUsedBreadthOfSpecifiedLength(direction, trackLength);
 370
 371     ASSERT(trackLength.isMinContent() || trackLength.isMaxContent());
 372     return 0;
 373 }
 374
 375 LayoutUnit RenderGrid::computeUsedBreadthOfMaxLength(GridTrackSizingDirection direction, const GridLength& gridLength, LayoutUnit usedBreadth) const
 376 {
 377     if (gridLength.isFlex())
 378         return usedBreadth;
 379
 380     const Length& trackLength = gridLength.length();
 381     ASSERT(!trackLength.isAuto());
 382     if (trackLength.isSpecified()) {
 383         LayoutUnit computedBreadth = computeUsedBreadthOfSpecifiedLength(direction, trackLength);
 384         ASSERT(computedBreadth != infinity);
 385         return computedBreadth;
 386     }
 387
 388     ASSERT(trackLength.isMinContent() || trackLength.isMaxContent());
 389     return infinity;
 390 }
 391
 392 LayoutUnit RenderGrid::computeUsedBreadthOfSpecifiedLength(GridTrackSizingDirection direction, const Length& trackLength) const
 393 {
 394     ASSERT(trackLength.isSpecified());
 395     return valueForLength(trackLength, direction == ForColumns ? logicalWidth() : computeContentLogicalHeight(style().logicalHeight()));
 396 }
 397
 398 double RenderGrid::computeNormalizedFractionBreadth(Vector<GridTrack>& tracks, const GridSpan& tracksSpan, GridTrackSizingDirection direction, LayoutUnit availableLogicalSpace) const
 399 {
 400     // |availableLogicalSpace| already accounts for the used breadths so no need to remove it here.
 401
 402     Vector<GridTrackForNormalization> tracksForNormalization;
 403     for (size_t i = tracksSpan.initialPositionIndex; i <= tracksSpan.finalPositionIndex; ++i) {
 404         const GridTrackSize& trackSize = gridTrackSize(direction, i);
 405         if (!trackSize.maxTrackBreadth().isFlex())
 406             continue;
 407
 408         tracksForNormalization.append(GridTrackForNormalization(tracks[i], trackSize.maxTrackBreadth().flex()));
 409     }
 410
 411     // The function is not called if we don't have <flex> grid tracks
 412     ASSERT(!tracksForNormalization.isEmpty());
 413
 414     std::sort(tracksForNormalization.begin(), tracksForNormalization.end(),
 415               [](const GridTrackForNormalization& track1, const GridTrackForNormalization& track2) {
 416                   return track1.m_normalizedFlexValue < track2.m_normalizedFlexValue;
 417               });
 418
 419     // These values work together: as we walk over our grid tracks, we increase fractionValueBasedOnGridItemsRatio
 420     // to match a grid track's usedBreadth to <flex> ratio until the total fractions sized grid tracks wouldn't
 421     // fit into availableLogicalSpaceIgnoringFractionTracks.
 422     double accumulatedFractions = 0;
 423     LayoutUnit fractionValueBasedOnGridItemsRatio = 0;
 424     LayoutUnit availableLogicalSpaceIgnoringFractionTracks = availableLogicalSpace;
 425
 426     for (size_t i = 0; i < tracksForNormalization.size(); ++i) {
 427         const GridTrackForNormalization& track = tracksForNormalization[i];
 428         if (track.m_normalizedFlexValue > fractionValueBasedOnGridItemsRatio) {
 429             // If the normalized flex value (we ordered |tracksForNormalization| by increasing normalized flex value)
 430             // will make us overflow our container, then stop. We have the previous step's ratio is the best fit.
 431             if (track.m_normalizedFlexValue * accumulatedFractions > availableLogicalSpaceIgnoringFractionTracks)
 432                 break;
 433
 434             fractionValueBasedOnGridItemsRatio = track.m_normalizedFlexValue;
 435         }
 436
 437         accumulatedFractions += track.m_flex;
 438         // This item was processed so we re-add its used breadth to the available space to accurately count the remaining space.
 439         availableLogicalSpaceIgnoringFractionTracks += track.m_track->m_usedBreadth;
 440     }
 441
 442     return availableLogicalSpaceIgnoringFractionTracks / accumulatedFractions;
 443 }
 444
 445 const GridTrackSize& RenderGrid::gridTrackSize(GridTrackSizingDirection direction, size_t i) const
 446 {
 447     const Vector<GridTrackSize>& trackStyles = (direction == ForColumns) ? style().gridColumns() : style().gridRows();
 448     if (i >= trackStyles.size())
 449         return (direction == ForColumns) ? style().gridAutoColumns() : style().gridAutoRows();
 450
 451     const GridTrackSize& trackSize = trackStyles[i];
 452     // If the logical width/height of the grid container is indefinite, percentage values are treated as <auto>.
 453     if (trackSize.isPercentage()) {
 454         Length logicalSize = direction == ForColumns ? style().logicalWidth() : style().logicalHeight();
 455         if (logicalSize.isIntrinsicOrAuto()) {
 456             static NeverDestroyed<GridTrackSize> autoTrackSize(Auto);
 457             return autoTrackSize.get();
 458         }
 459     }
 460
 461     return trackSize;
 462 }
 463
 464 size_t RenderGrid::explicitGridColumnCount() const
 465 {
 466     return style().gridColumns().size();
 467 }
 468
 469 size_t RenderGrid::explicitGridRowCount() const
 470 {
 471     return style().gridRows().size();
 472 }
 473
 474 static inline bool isColumnSide(GridPositionSide side)
 475 {
 476     return side == ColumnStartSide || side == ColumnEndSide;
 477 }
 478
 479 size_t RenderGrid::explicitGridSizeForSide(GridPositionSide side) const
 480 {
 481     return isColumnSide(side) ? explicitGridColumnCount() : explicitGridRowCount();
 482 }
 483
 484 LayoutUnit RenderGrid::logicalContentHeightForChild(RenderBox* child, Vector<GridTrack>& columnTracks)
 485 {
 486     LayoutUnit oldOverrideContainingBlockContentLogicalWidth = child->hasOverrideContainingBlockLogicalWidth() ? child->overrideContainingBlockContentLogicalWidth() : LayoutUnit();
 487     LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(child, ForColumns, columnTracks);
 488     if (child->style().logicalHeight().isPercent() || oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth)
 489         child->setNeedsLayout(MarkOnlyThis);
 490
 491     child->setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
 492     // If |child| has a percentage logical height, we shouldn't let it override its intrinsic height, which is
 493     // what we are interested in here. Thus we need to set the override logical height to -1 (no possible resolution).
 494     child->setOverrideContainingBlockContentLogicalHeight(-1);
 495     child->layoutIfNeeded();
 496     return child->logicalHeight() + child->marginLogicalHeight();
 497 }
 498
 499 LayoutUnit RenderGrid::minContentForChild(RenderBox* child, GridTrackSizingDirection direction, Vector<GridTrack>& columnTracks)
 500 {
 501     bool hasOrthogonalWritingMode = child->isHorizontalWritingMode() != isHorizontalWritingMode();
 502     // FIXME: Properly support orthogonal writing mode.
 503     if (hasOrthogonalWritingMode)
 504         return 0;
 505
 506     if (direction == ForColumns) {
 507         // FIXME: It's unclear if we should return the intrinsic width or the preferred width.
 508         // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
 509         return child->minPreferredLogicalWidth() + marginIntrinsicLogicalWidthForChild(*child);
 510     }
 511
 512     return logicalContentHeightForChild(child, columnTracks);
 513 }
 514
 515 LayoutUnit RenderGrid::maxContentForChild(RenderBox* child, GridTrackSizingDirection direction, Vector<GridTrack>& columnTracks)
 516 {
 517     bool hasOrthogonalWritingMode = child->isHorizontalWritingMode() != isHorizontalWritingMode();
 518     // FIXME: Properly support orthogonal writing mode.
 519     if (hasOrthogonalWritingMode)
 520         return LayoutUnit();
 521
 522     if (direction == ForColumns) {
 523         // FIXME: It's unclear if we should return the intrinsic width or the preferred width.
 524         // See http://lists.w3.org/Archives/Public/www-style/2013Jan/0245.html
 525         return child->maxPreferredLogicalWidth() + marginIntrinsicLogicalWidthForChild(*child);
 526     }
 527
 528     return logicalContentHeightForChild(child, columnTracks);
 529 }
 530
 531 void RenderGrid::resolveContentBasedTrackSizingFunctions(GridTrackSizingDirection direction, GridSizingData& sizingData)
 532 {
 533     // FIXME: Split the grid tracks into groups that doesn't overlap a <flex> grid track.
 534
 535     for (size_t i = 0; i < sizingData.contentSizedTracksIndex.size(); ++i) {
 536         GridIterator iterator(m_grid, direction, sizingData.contentSizedTracksIndex[i]);
 537         while (RenderBox* gridItem = iterator.nextGridItem()) {
 538             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMinOrMaxContentMinTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth);
 539             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMaxContentMinTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::usedBreadth, &GridTrack::growUsedBreadth);
 540             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMinOrMaxContentMaxTrackBreadth, &RenderGrid::minContentForChild, &GridTrack::maxBreadthIfNotInfinite, &GridTrack::growMaxBreadth);
 541             resolveContentBasedTrackSizingFunctionsForItems(direction, sizingData, gridItem, &GridTrackSize::hasMaxContentMaxTrackBreadth, &RenderGrid::maxContentForChild, &GridTrack::maxBreadthIfNotInfinite, &GridTrack::growMaxBreadth);
 542         }
 543
 544         GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[i] : sizingData.rowTracks[i];
 545         if (track.m_maxBreadth == infinity)
 546             track.m_maxBreadth = track.m_usedBreadth;
 547     }
 548 }
 549
 550 void RenderGrid::resolveContentBasedTrackSizingFunctionsForItems(GridTrackSizingDirection direction, GridSizingData& sizingData, RenderBox* gridItem, FilterFunction filterFunction, SizingFunction sizingFunction, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction)
 551 {
 552     const GridCoordinate coordinate = cachedGridCoordinate(gridItem);
 553     const size_t initialTrackIndex = (direction == ForColumns) ? coordinate.columns.initialPositionIndex : coordinate.rows.initialPositionIndex;
 554     const size_t finalTrackIndex = (direction == ForColumns) ? coordinate.columns.finalPositionIndex : coordinate.rows.finalPositionIndex;
 555
 556     sizingData.filteredTracks.shrink(0);
 557     for (size_t trackIndex = initialTrackIndex; trackIndex <= finalTrackIndex; ++trackIndex) {
 558         const GridTrackSize& trackSize = gridTrackSize(direction, trackIndex);
 559         if (!(trackSize.*filterFunction)())
 560             continue;
 561
 562         GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackIndex] : sizingData.rowTracks[trackIndex];
 563         sizingData.filteredTracks.append(&track);
 564     }
 565
 566     if (sizingData.filteredTracks.isEmpty())
 567         return;
 568
 569     LayoutUnit additionalBreadthSpace = (this->*sizingFunction)(gridItem, direction, sizingData.columnTracks);
 570     for (size_t trackIndexForSpace = initialTrackIndex; trackIndexForSpace <= finalTrackIndex; ++trackIndexForSpace) {
 571         GridTrack& track = (direction == ForColumns) ? sizingData.columnTracks[trackIndexForSpace] : sizingData.rowTracks[trackIndexForSpace];
 572         additionalBreadthSpace -= (track.*trackGetter)();
 573     }
 574
 575     // FIXME: We should pass different values for |tracksForGrowthAboveMaxBreadth|.
 576     distributeSpaceToTracks(sizingData.filteredTracks, &sizingData.filteredTracks, trackGetter, trackGrowthFunction, sizingData, additionalBreadthSpace);
 577 }
 578
 579 static bool sortByGridTrackGrowthPotential(const GridTrack* track1, const GridTrack* track2)
 580 {
 581     return (track1->m_maxBreadth - track1->m_usedBreadth) < (track2->m_maxBreadth - track2->m_usedBreadth);
 582 }
 583
 584 void RenderGrid::distributeSpaceToTracks(Vector<GridTrack*>& tracks, Vector<GridTrack*>* tracksForGrowthAboveMaxBreadth, AccumulatorGetter trackGetter, AccumulatorGrowFunction trackGrowthFunction, GridSizingData& sizingData, LayoutUnit& availableLogicalSpace)
 585 {
 586     std::sort(tracks.begin(), tracks.end(), sortByGridTrackGrowthPotential);
 587
 588     size_t tracksSize = tracks.size();
 589     sizingData.distributeTrackVector.resize(tracksSize);
 590
 591     for (size_t i = 0; i < tracksSize; ++i) {
 592         GridTrack& track = *tracks[i];
 593         LayoutUnit availableLogicalSpaceShare = availableLogicalSpace / (tracksSize - i);
 594         LayoutUnit trackBreadth = (tracks[i]->*trackGetter)();
 595         LayoutUnit growthShare = std::max(LayoutUnit(), std::min(availableLogicalSpaceShare, track.m_maxBreadth - trackBreadth));
 596         // We should never shrink any grid track or else we can't guarantee we abide by our min-sizing function.
 597         sizingData.distributeTrackVector[i] = trackBreadth + growthShare;
 598         availableLogicalSpace -= growthShare;
 599     }
 600
 601     if (availableLogicalSpace > 0 && tracksForGrowthAboveMaxBreadth) {
 602         tracksSize = tracksForGrowthAboveMaxBreadth->size();
 603         for (size_t i = 0; i < tracksSize; ++i) {
 604             LayoutUnit growthShare = availableLogicalSpace / (tracksSize - i);
 605             sizingData.distributeTrackVector[i] += growthShare;
 606             availableLogicalSpace -= growthShare;
 607         }
 608     }
 609
 610     for (size_t i = 0; i < tracksSize; ++i) {
 611         LayoutUnit growth = sizingData.distributeTrackVector[i] - (tracks[i]->*trackGetter)();
 612         if (growth >= 0)
 613             (tracks[i]->*trackGrowthFunction)(growth);
 614     }
 615 }
 616
 617 #ifndef NDEBUG
 618 bool RenderGrid::tracksAreWiderThanMinTrackBreadth(GridTrackSizingDirection direction, const Vector<GridTrack>& tracks)
 619 {
 620     for (size_t i = 0; i < tracks.size(); ++i) {
 621         const GridTrackSize& trackSize = gridTrackSize(direction, i);
 622         const GridLength& minTrackBreadth = trackSize.minTrackBreadth();
 623         if (computeUsedBreadthOfMinLength(direction, minTrackBreadth) > tracks[i].m_usedBreadth)
 624             return false;
 625     }
 626     return true;
 627 }
 628 #endif
 629
 630 void RenderGrid::growGrid(GridTrackSizingDirection direction)
 631 {
 632     if (direction == ForColumns) {
 633         const size_t oldColumnSize = gridColumnCount();
 634         for (size_t row = 0; row < gridRowCount(); ++row)
 635             m_grid[row].grow(oldColumnSize + 1);
 636     } else {
 637         const size_t oldRowSize = gridRowCount();
 638         m_grid.grow(oldRowSize + 1);
 639         m_grid[oldRowSize].grow(gridColumnCount());
 640     }
 641 }
 642
 643 void RenderGrid::insertItemIntoGrid(RenderBox* child, const GridCoordinate& coordinate)
 644 {
 645     for (size_t row = coordinate.rows.initialPositionIndex; row <= coordinate.rows.finalPositionIndex; ++row) {
 646         for (size_t column = coordinate.columns.initialPositionIndex; column <= coordinate.columns.finalPositionIndex; ++column)
 647             m_grid[row][column].append(child);
 648     }
 649     m_gridItemCoordinate.set(child, coordinate);
 650 }
 651
 652 void RenderGrid::insertItemIntoGrid(RenderBox* child, size_t rowTrack, size_t columnTrack)
 653 {
 654     const GridSpan& rowSpan = resolveGridPositionsFromAutoPlacementPosition(child, ForRows, rowTrack);
 655     const GridSpan& columnSpan = resolveGridPositionsFromAutoPlacementPosition(child, ForColumns, columnTrack);
 656     insertItemIntoGrid(child, GridCoordinate(rowSpan, columnSpan));
 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     GridAutoFlow autoFlow = style().gridAutoFlow();
 669     for (RenderBox* child = m_orderIterator.first(); child; child = m_orderIterator.next()) {
 670         // FIXME: We never re-resolve positions if the grid is grown during auto-placement which may lead auto / <integer>
 671         // positions to not match the author's intent. The specification is unclear on what should be done in this case.
 672         std::unique_ptr<GridSpan> rowPositions = resolveGridPositionsFromStyle(child, ForRows);
 673         std::unique_ptr<GridSpan> columnPositions = resolveGridPositionsFromStyle(child, ForColumns);
 674         if (!rowPositions || !columnPositions) {
 675             GridSpan* majorAxisPositions = (autoPlacementMajorAxisDirection() == ForColumns) ? columnPositions.get() : rowPositions.get();
 676             if (!majorAxisPositions)
 677                 autoMajorAxisAutoGridItems.append(child);
 678             else
 679                 specifiedMajorAxisAutoGridItems.append(child);
 680             continue;
 681         }
 682         insertItemIntoGrid(child, GridCoordinate(*rowPositions, *columnPositions));
 683     }
 684
 685     ASSERT(gridRowCount() >= style().gridRows().size());
 686     ASSERT(gridColumnCount() >= style().gridColumns().size());
 687
 688     if (autoFlow == AutoFlowNone) {
 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     // FIXME: We should find a way to share OrderValues's initialization code with RenderFlexibleBox.
 702     OrderIterator::OrderValues orderValues;
 703     size_t maximumRowIndex = std::max<size_t>(1, explicitGridRowCount());
 704     size_t maximumColumnIndex = std::max<size_t>(1, explicitGridColumnCount());
 705
 706     for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
 707         // Avoid growing the vector for the common-case default value of 0. This optimizes the most common case which is
 708         // one or a few values with the default order 0
 709         int order = child->style().order();
 710         if (orderValues.isEmpty() || orderValues.last() != order)
 711             orderValues.append(order);
 712
 713         // This function bypasses the cache (cachedGridCoordinate()) as it is used to build it.
 714         std::unique_ptr<GridSpan> rowPositions = resolveGridPositionsFromStyle(child, ForRows);
 715         std::unique_ptr<GridSpan> columnPositions = resolveGridPositionsFromStyle(child, ForColumns);
 716
 717         // |positions| is 0 if we need to run the auto-placement algorithm. Our estimation ignores
 718         // this case as the auto-placement algorithm will grow the grid as needed.
 719         if (rowPositions)
 720             maximumRowIndex = std::max(maximumRowIndex, rowPositions->finalPositionIndex + 1);
 721         if (columnPositions)
 722             maximumColumnIndex = std::max(maximumColumnIndex, columnPositions->finalPositionIndex + 1);
 723     }
 724
 725     m_grid.grow(maximumRowIndex);
 726     for (size_t i = 0; i < m_grid.size(); ++i)
 727         m_grid[i].grow(maximumColumnIndex);
 728
 729     m_orderIterator.setOrderValues(std::move(orderValues));
 730 }
 731
 732 void RenderGrid::placeSpecifiedMajorAxisItemsOnGrid(const Vector<RenderBox*>& autoGridItems)
 733 {
 734     for (auto& autoGridItem : autoGridItems) {
 735         std::unique_ptr<GridSpan> majorAxisPositions = resolveGridPositionsFromStyle(autoGridItem, autoPlacementMajorAxisDirection());
 736         GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions->initialPositionIndex);
 737         if (std::unique_ptr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea()) {
 738             insertItemIntoGrid(autoGridItem, emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
 739             continue;
 740         }
 741
 742         growGrid(autoPlacementMinorAxisDirection());
 743         std::unique_ptr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea();
 744         ASSERT(emptyGridArea);
 745         insertItemIntoGrid(autoGridItem, emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
 746     }
 747 }
 748
 749 void RenderGrid::placeAutoMajorAxisItemsOnGrid(const Vector<RenderBox*>& autoGridItems)
 750 {
 751     for (auto& autoGridItem : autoGridItems)
 752         placeAutoMajorAxisItemOnGrid(autoGridItem);
 753 }
 754
 755 void RenderGrid::placeAutoMajorAxisItemOnGrid(RenderBox* gridItem)
 756 {
 757     std::unique_ptr<GridSpan> minorAxisPositions = resolveGridPositionsFromStyle(gridItem, autoPlacementMinorAxisDirection());
 758     ASSERT(!resolveGridPositionsFromStyle(gridItem, autoPlacementMajorAxisDirection()));
 759     size_t minorAxisIndex = 0;
 760     if (minorAxisPositions) {
 761         minorAxisIndex = minorAxisPositions->initialPositionIndex;
 762         GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisIndex);
 763         if (std::unique_ptr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea()) {
 764             insertItemIntoGrid(gridItem, emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
 765             return;
 766         }
 767     } else {
 768         const size_t endOfMajorAxis = (autoPlacementMajorAxisDirection() == ForColumns) ? gridColumnCount() : gridRowCount();
 769         for (size_t majorAxisIndex = 0; majorAxisIndex < endOfMajorAxis; ++majorAxisIndex) {
 770             GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisIndex);
 771             if (std::unique_ptr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea()) {
 772                 insertItemIntoGrid(gridItem, emptyGridArea->rows.initialPositionIndex, emptyGridArea->columns.initialPositionIndex);
 773                 return;
 774             }
 775         }
 776     }
 777
 778     // We didn't find an empty grid area so we need to create an extra major axis line and insert our gridItem in it.
 779     const size_t columnIndex = (autoPlacementMajorAxisDirection() == ForColumns) ? gridColumnCount() : minorAxisIndex;
 780     const size_t rowIndex = (autoPlacementMajorAxisDirection() == ForColumns) ? minorAxisIndex : gridRowCount();
 781     growGrid(autoPlacementMajorAxisDirection());
 782     insertItemIntoGrid(gridItem, rowIndex, columnIndex);
 783 }
 784
 785 RenderGrid::GridTrackSizingDirection RenderGrid::autoPlacementMajorAxisDirection() const
 786 {
 787     GridAutoFlow flow = style().gridAutoFlow();
 788     ASSERT(flow != AutoFlowNone);
 789     return (flow == AutoFlowColumn) ? ForColumns : ForRows;
 790 }
 791
 792 RenderGrid::GridTrackSizingDirection RenderGrid::autoPlacementMinorAxisDirection() const
 793 {
 794     GridAutoFlow flow = style().gridAutoFlow();
 795     ASSERT(flow != AutoFlowNone);
 796     return (flow == AutoFlowColumn) ? ForRows : ForColumns;
 797 }
 798
 799 void RenderGrid::clearGrid()
 800 {
 801     m_grid.clear();
 802     m_gridItemCoordinate.clear();
 803 }
 804
 805 void RenderGrid::layoutGridItems()
 806 {
 807     placeItemsOnGrid();
 808
 809     GridSizingData sizingData(gridColumnCount(), gridRowCount());
 810     computeUsedBreadthOfGridTracks(ForColumns, sizingData);
 811     ASSERT(tracksAreWiderThanMinTrackBreadth(ForColumns, sizingData.columnTracks));
 812     computeUsedBreadthOfGridTracks(ForRows, sizingData);
 813     ASSERT(tracksAreWiderThanMinTrackBreadth(ForRows, sizingData.rowTracks));
 814
 815     populateGridPositions(sizingData);
 816
 817     for (RenderBox* child = firstChildBox(); child; child = child->nextSiblingBox()) {
 818         // Because the grid area cannot be styled, we don't need to adjust
 819         // the grid breadth to account for 'box-sizing'.
 820         LayoutUnit oldOverrideContainingBlockContentLogicalWidth = child->hasOverrideContainingBlockLogicalWidth() ? child->overrideContainingBlockContentLogicalWidth() : LayoutUnit();
 821         LayoutUnit oldOverrideContainingBlockContentLogicalHeight = child->hasOverrideContainingBlockLogicalHeight() ? child->overrideContainingBlockContentLogicalHeight() : LayoutUnit();
 822
 823         LayoutUnit overrideContainingBlockContentLogicalWidth = gridAreaBreadthForChild(child, ForColumns, sizingData.columnTracks);
 824         LayoutUnit overrideContainingBlockContentLogicalHeight = gridAreaBreadthForChild(child, ForRows, sizingData.rowTracks);
 825         if (oldOverrideContainingBlockContentLogicalWidth != overrideContainingBlockContentLogicalWidth || (oldOverrideContainingBlockContentLogicalHeight != overrideContainingBlockContentLogicalHeight && (child->hasRelativeLogicalHeight() || child->hasViewportPercentageLogicalHeight())))
 826             child->setNeedsLayout(MarkOnlyThis);
 827
 828         child->setOverrideContainingBlockContentLogicalWidth(overrideContainingBlockContentLogicalWidth);
 829         child->setOverrideContainingBlockContentLogicalHeight(overrideContainingBlockContentLogicalHeight);
 830
 831         LayoutRect oldChildRect = child->frameRect();
 832
 833         // FIXME: Grid items should stretch to fill their cells. Once we
 834         // implement grid-{column,row}-align, we can also shrink to fit. For
 835         // now, just size as if we were a regular child.
 836         child->layoutIfNeeded();
 837
 838         child->setLogicalLocation(findChildLogicalPosition(child, sizingData));
 839
 840         // If the child moved, we have to repaint it as well as any floating/positioned
 841         // descendants. An exception is if we need a layout. In this case, we know we're going to
 842         // repaint ourselves (and the child) anyway.
 843         if (!selfNeedsLayout() && child->checkForRepaintDuringLayout())
 844             child->repaintDuringLayoutIfMoved(oldChildRect);
 845     }
 846
 847     for (size_t i = 0; i < sizingData.rowTracks.size(); ++i)
 848         setLogicalHeight(logicalHeight() + sizingData.rowTracks[i].m_usedBreadth);
 849
 850     // min / max logical height is handled in updateLogicalHeight().
 851     setLogicalHeight(logicalHeight() + borderAndPaddingLogicalHeight());
 852     clearGrid();
 853 }
 854
 855 GridCoordinate RenderGrid::cachedGridCoordinate(const RenderBox* gridItem) const
 856 {
 857     ASSERT(m_gridItemCoordinate.contains(gridItem));
 858     return m_gridItemCoordinate.get(gridItem);
 859 }
 860
 861 GridSpan RenderGrid::resolveGridPositionsFromAutoPlacementPosition(const RenderBox*, GridTrackSizingDirection, size_t initialPosition) const
 862 {
 863     // FIXME: We don't support spanning with auto positions yet. Once we do, this is wrong. Also we should make
 864     // sure the grid can accomodate the new item as we only grow 1 position in a given direction.
 865     return GridSpan(initialPosition, initialPosition);
 866 }
 867
 868 static inline bool gridLineDefinedBeforeGridArea(size_t namedGridLineFirstDefinition, const GridCoordinate& gridAreaCoordinates, GridPositionSide side)
 869 {
 870     switch (side) {
 871     case ColumnStartSide:
 872         return namedGridLineFirstDefinition < gridAreaCoordinates.columns.initialPositionIndex;
 873     case ColumnEndSide:
 874         return namedGridLineFirstDefinition < gridAreaCoordinates.columns.finalPositionIndex;
 875     case RowStartSide:
 876         return namedGridLineFirstDefinition < gridAreaCoordinates.rows.initialPositionIndex;
 877     case RowEndSide:
 878         return namedGridLineFirstDefinition < gridAreaCoordinates.rows.finalPositionIndex;
 879     }
 880     ASSERT_NOT_REACHED();
 881     return false;
 882 }
 883
 884 static void setNamedLinePositionIfDefinedBeforeArea(GridPosition& position, const NamedGridLinesMap& namedLinesMap, const String& lineName, const GridCoordinate& gridAreaCoordinate, GridPositionSide side)
 885 {
 886     auto linesIterator = namedLinesMap.find(lineName);
 887     if (linesIterator == namedLinesMap.end())
 888         return;
 889
 890     size_t namedGridLineFirstDefinition = GridPosition::adjustGridPositionForSide(linesIterator->value[0], side);
 891     if (gridLineDefinedBeforeGridArea(namedGridLineFirstDefinition, gridAreaCoordinate, side))
 892         position.setExplicitPosition(1, lineName);
 893 }
 894
 895 void RenderGrid::adjustNamedGridItemPosition(GridPosition& position, GridPositionSide side) const
 896 {
 897     // The StyleBuilder always treats <custom-ident> as a named grid area. We must decide here if they are going to be
 898     // resolved to either a grid area or a grid line.
 899     ASSERT(position.isNamedGridArea());
 900     const NamedGridAreaMap& gridAreaMap = style().namedGridArea();
 901     const NamedGridLinesMap& namedLinesMap = isColumnSide(side) ? style().namedGridColumnLines() : style().namedGridRowLines();
 902
 903     String namedGridAreaOrGridLine = position.namedGridLine();
 904     bool isStartSide = side == ColumnStartSide || side == RowStartSide;
 905
 906     auto areaIterator = gridAreaMap.find(namedGridAreaOrGridLine);
 907     if (areaIterator != gridAreaMap.end()) {
 908         String gridLineName = namedGridAreaOrGridLine + (isStartSide ? "-start" : "-end");
 909         setNamedLinePositionIfDefinedBeforeArea(position, namedLinesMap, gridLineName, areaIterator->value, side);
 910         return;
 911     }
 912
 913     bool hasStartSuffix = namedGridAreaOrGridLine.endsWith("-start");
 914     bool hasEndSuffix = namedGridAreaOrGridLine.endsWith("-end");
 915     if ((hasStartSuffix && isStartSide) || (hasEndSuffix && !isStartSide)) {
 916         size_t suffixLength = hasStartSuffix ? strlen("-start") : strlen("-end");
 917         String gridAreaName = namedGridAreaOrGridLine.substring(0, namedGridAreaOrGridLine.length() - suffixLength);
 918
 919         auto areaIterator = gridAreaMap.find(gridAreaName);
 920         if (areaIterator != gridAreaMap.end()) {
 921             position.setNamedGridArea(gridAreaName);
 922             setNamedLinePositionIfDefinedBeforeArea(position, namedLinesMap, namedGridAreaOrGridLine, areaIterator->value, side);
 923             return;
 924         }
 925     }
 926
 927     if (namedLinesMap.contains(namedGridAreaOrGridLine))
 928         position.setExplicitPosition(1, namedGridAreaOrGridLine);
 929     else
 930         position.setAutoPosition();
 931 }
 932
 933 void RenderGrid::adjustGridPositionsFromStyle(GridPosition& initialPosition, GridPosition& finalPosition, GridPositionSide initialPositionSide, GridPositionSide finalPositionSide) const
 934 {
 935     ASSERT(isColumnSide(initialPositionSide) == isColumnSide(finalPositionSide));
 936
 937     // We must handle the placement error handling code here instead of in the StyleAdjuster because we don't want to
 938     // overwrite the specified values.
 939     if (initialPosition.isSpan() && finalPosition.isSpan())
 940         finalPosition.setAutoPosition();
 941
 942     if (initialPosition.isNamedGridArea())
 943         adjustNamedGridItemPosition(initialPosition, initialPositionSide);
 944
 945     if (finalPosition.isNamedGridArea())
 946         adjustNamedGridItemPosition(finalPosition, finalPositionSide);
 947 }
 948
 949 std::unique_ptr<GridSpan> RenderGrid::resolveGridPositionsFromStyle(const RenderBox* gridItem, GridTrackSizingDirection direction) const
 950 {
 951     GridPosition initialPosition = (direction == ForColumns) ? gridItem->style().gridItemColumnStart() : gridItem->style().gridItemRowStart();
 952     const GridPositionSide initialPositionSide = (direction == ForColumns) ? ColumnStartSide : RowStartSide;
 953     GridPosition finalPosition = (direction == ForColumns) ? gridItem->style().gridItemColumnEnd() : gridItem->style().gridItemRowEnd();
 954     const GridPositionSide finalPositionSide = (direction == ForColumns) ? ColumnEndSide : RowEndSide;
 955
 956     adjustGridPositionsFromStyle(initialPosition, finalPosition, initialPositionSide, finalPositionSide);
 957
 958     if (initialPosition.shouldBeResolvedAgainstOppositePosition() && finalPosition.shouldBeResolvedAgainstOppositePosition()) {
 959         if (style().gridAutoFlow() == AutoFlowNone)
 960             return std::make_unique<GridSpan>(0, 0);
 961
 962         // We can't get our grid positions without running the auto placement algorithm.
 963         return nullptr;
 964     }
 965
 966     if (initialPosition.shouldBeResolvedAgainstOppositePosition()) {
 967         // Infer the position from the final position ('auto / 1' or 'span 2 / 3' case).
 968         const size_t finalResolvedPosition = resolveGridPositionFromStyle(finalPosition, finalPositionSide);
 969         return resolveGridPositionAgainstOppositePosition(finalResolvedPosition, initialPosition, initialPositionSide);
 970     }
 971
 972     if (finalPosition.shouldBeResolvedAgainstOppositePosition()) {
 973         // Infer our position from the initial position ('1 / auto' or '3 / span 2' case).
 974         const size_t initialResolvedPosition = resolveGridPositionFromStyle(initialPosition, initialPositionSide);
 975         return resolveGridPositionAgainstOppositePosition(initialResolvedPosition, finalPosition, finalPositionSide);
 976     }
 977
 978     size_t resolvedInitialPosition = resolveGridPositionFromStyle(initialPosition, initialPositionSide);
 979     size_t resolvedFinalPosition = resolveGridPositionFromStyle(finalPosition, finalPositionSide);
 980
 981     // If 'grid-row-end' specifies a line at or before that specified by 'grid-row-start', it computes to 'span 1'.
 982     if (resolvedFinalPosition < resolvedInitialPosition)
 983         resolvedFinalPosition = resolvedInitialPosition;
 984
 985     return std::make_unique<GridSpan>(resolvedInitialPosition, resolvedFinalPosition);
 986 }
 987
 988 size_t RenderGrid::resolveNamedGridLinePositionFromStyle(const GridPosition& position, GridPositionSide side) const
 989 {
 990     ASSERT(!position.namedGridLine().isNull());
 991
 992     const NamedGridLinesMap& gridLinesNames = isColumnSide(side) ? style().namedGridColumnLines() : style().namedGridRowLines();
 993     NamedGridLinesMap::const_iterator it = gridLinesNames.find(position.namedGridLine());
 994     if (it == gridLinesNames.end()) {
 995         if (position.isPositive())
 996             return 0;
 997         const size_t lastLine = explicitGridSizeForSide(side);
 998         return GridPosition::adjustGridPositionForSide(lastLine, side);
 999     }
1000
1001     size_t namedGridLineIndex;
1002     if (position.isPositive())
1003         namedGridLineIndex = std::min<size_t>(position.integerPosition(), it->value.size()) - 1;
1004     else
1005         namedGridLineIndex = std::max<int>(it->value.size() - abs(position.integerPosition()), 0);
1006     return GridPosition::adjustGridPositionForSide(it->value[namedGridLineIndex], side);
1007 }
1008
1009 size_t RenderGrid::resolveGridPositionFromStyle(const GridPosition& position, GridPositionSide side) const
1010 {
1011     switch (position.type()) {
1012     case ExplicitPosition: {
1013         ASSERT(position.integerPosition());
1014
1015         if (!position.namedGridLine().isNull())
1016             return resolveNamedGridLinePositionFromStyle(position, side);
1017
1018         // Handle <integer> explicit position.
1019         if (position.isPositive())
1020             return GridPosition::adjustGridPositionForSide(position.integerPosition() - 1, side);
1021
1022         size_t resolvedPosition = abs(position.integerPosition()) - 1;
1023         const size_t endOfTrack = explicitGridSizeForSide(side);
1024
1025         // Per http://lists.w3.org/Archives/Public/www-style/2013Mar/0589.html, we clamp negative value to the first line.
1026         if (endOfTrack < resolvedPosition)
1027             return 0;
1028
1029         return GridPosition::adjustGridPositionForSide(endOfTrack - resolvedPosition, side);
1030     }
1031     case NamedGridAreaPosition:
1032     {
1033         NamedGridAreaMap::const_iterator it = style().namedGridArea().find(position.namedGridLine());
1034         // Unknown grid area should have been computed to 'auto' by now.
1035         ASSERT(it != style().namedGridArea().end());
1036         const GridCoordinate& gridAreaCoordinate = it->value;
1037         switch (side) {
1038         case ColumnStartSide:
1039             return gridAreaCoordinate.columns.initialPositionIndex;
1040         case ColumnEndSide:
1041             return gridAreaCoordinate.columns.finalPositionIndex;
1042         case RowStartSide:
1043             return gridAreaCoordinate.rows.initialPositionIndex;
1044         case RowEndSide:
1045             return gridAreaCoordinate.rows.finalPositionIndex;
1046         }
1047         ASSERT_NOT_REACHED();
1048         return 0;
1049     }
1050     case AutoPosition:
1051     case SpanPosition:
1052         // 'auto' and span depend on the opposite position for resolution (e.g. grid-row: auto / 1 or grid-column: span 3 / "myHeader").
1053         ASSERT_NOT_REACHED();
1054         return 0;
1055     }
1056     ASSERT_NOT_REACHED();
1057     return 0;
1058 }
1059
1060 std::unique_ptr<GridSpan> RenderGrid::resolveGridPositionAgainstOppositePosition(size_t resolvedOppositePosition, const GridPosition& position, GridPositionSide side) const
1061 {
1062     if (position.isAuto())
1063         return std::make_unique<GridSpan>(resolvedOppositePosition, resolvedOppositePosition);
1064
1065     ASSERT(position.isSpan());
1066     ASSERT(position.spanPosition() > 0);
1067
1068     if (!position.namedGridLine().isNull()) {
1069         // span 2 'c' -> we need to find the appropriate grid line before / after our opposite position.
1070         return resolveNamedGridLinePositionAgainstOppositePosition(resolvedOppositePosition, position, side);
1071     }
1072
1073     // 'span 1' is contained inside a single grid track regardless of the direction.
1074     // That's why the CSS span value is one more than the offset we apply.
1075     size_t positionOffset = position.spanPosition() - 1;
1076     if (side == ColumnStartSide || side == RowStartSide) {
1077         size_t initialResolvedPosition = std::max<int>(0, resolvedOppositePosition - positionOffset);
1078         return std::make_unique<GridSpan>(initialResolvedPosition, resolvedOppositePosition);
1079     }
1080
1081     return std::make_unique<GridSpan>(resolvedOppositePosition, resolvedOppositePosition + positionOffset);
1082 }
1083
1084 std::unique_ptr<GridSpan> RenderGrid::resolveNamedGridLinePositionAgainstOppositePosition(size_t resolvedOppositePosition, const GridPosition& position, GridPositionSide side) const
1085 {
1086     ASSERT(position.isSpan());
1087     ASSERT(!position.namedGridLine().isNull());
1088     // Negative positions are not allowed per the specification and should have been handled during parsing.
1089     ASSERT(position.spanPosition() > 0);
1090
1091     const NamedGridLinesMap& gridLinesNames = isColumnSide(side) ? style().namedGridColumnLines() : style().namedGridRowLines();
1092     NamedGridLinesMap::const_iterator it = gridLinesNames.find(position.namedGridLine());
1093
1094     // If there is no named grid line of that name, we resolve the position to 'auto' (which is equivalent to 'span 1' in this case).
1095     // See http://lists.w3.org/Archives/Public/www-style/2013Jun/0394.html.
1096     if (it == gridLinesNames.end())
1097         return std::make_unique<GridSpan>(resolvedOppositePosition, resolvedOppositePosition);
1098
1099     if (side == RowStartSide || side == ColumnStartSide)
1100         return resolveRowStartColumnStartNamedGridLinePositionAgainstOppositePosition(resolvedOppositePosition, position, it->value);
1101
1102     return resolveRowEndColumnEndNamedGridLinePositionAgainstOppositePosition(resolvedOppositePosition, position, it->value);
1103 }
1104
1105 static inline size_t firstNamedGridLineBeforePosition(size_t position, const Vector<size_t>& gridLines)
1106 {
1107     // The grid line inequality needs to be strict (which doesn't match the after / end case) because |position| is
1108     // already converted to an index in our grid representation (ie one was removed from the grid line to account for
1109     // the side).
1110     size_t firstLineBeforePositionIndex = 0;
1111     const size_t* firstLineBeforePosition = std::lower_bound(gridLines.begin(), gridLines.end(), position);
1112     if (firstLineBeforePosition != gridLines.end()) {
1113         if (*firstLineBeforePosition > position && firstLineBeforePosition != gridLines.begin())
1114             --firstLineBeforePosition;
1115
1116         firstLineBeforePositionIndex = firstLineBeforePosition - gridLines.begin();
1117     }
1118     return firstLineBeforePositionIndex;
1119 }
1120
1121 std::unique_ptr<GridSpan> RenderGrid::resolveRowStartColumnStartNamedGridLinePositionAgainstOppositePosition(size_t resolvedOppositePosition, const GridPosition& position, const Vector<size_t>& gridLines) const
1122 {
1123     size_t gridLineIndex = std::max<int>(0, firstNamedGridLineBeforePosition(resolvedOppositePosition, gridLines) - position.spanPosition() + 1);
1124     size_t resolvedGridLinePosition = gridLines[gridLineIndex];
1125     if (resolvedGridLinePosition > resolvedOppositePosition)
1126         resolvedGridLinePosition = resolvedOppositePosition;
1127     return std::make_unique<GridSpan>(resolvedGridLinePosition, resolvedOppositePosition);
1128 }
1129
1130 std::unique_ptr<GridSpan> RenderGrid::resolveRowEndColumnEndNamedGridLinePositionAgainstOppositePosition(size_t resolvedOppositePosition, const GridPosition& position, const Vector<size_t>& gridLines) const
1131 {
1132     size_t firstLineAfterOppositePositionIndex = gridLines.size() - 1;
1133     const size_t* firstLineAfterOppositePosition = std::upper_bound(gridLines.begin(), gridLines.end(), resolvedOppositePosition);
1134     if (firstLineAfterOppositePosition != gridLines.end())
1135         firstLineAfterOppositePositionIndex = firstLineAfterOppositePosition - gridLines.begin();
1136
1137     size_t gridLineIndex = std::min(gridLines.size() - 1, firstLineAfterOppositePositionIndex + position.spanPosition() - 1);
1138     size_t resolvedGridLinePosition = GridPosition::adjustGridPositionForRowEndColumnEndSide(gridLines[gridLineIndex]);
1139     if (resolvedGridLinePosition < resolvedOppositePosition)
1140         resolvedGridLinePosition = resolvedOppositePosition;
1141     return std::make_unique<GridSpan>(resolvedOppositePosition, resolvedGridLinePosition);
1142 }
1143
1144 LayoutUnit RenderGrid::gridAreaBreadthForChild(const RenderBox* child, GridTrackSizingDirection direction, const Vector<GridTrack>& tracks) const
1145 {
1146     const GridCoordinate& coordinate = cachedGridCoordinate(child);
1147     const GridSpan& span = (direction == ForColumns) ? coordinate.columns : coordinate.rows;
1148     LayoutUnit gridAreaBreadth = 0;
1149     for (size_t trackIndex = span.initialPositionIndex; trackIndex <= span.finalPositionIndex; ++trackIndex)
1150         gridAreaBreadth += tracks[trackIndex].m_usedBreadth;
1151     return gridAreaBreadth;
1152 }
1153
1154 void RenderGrid::populateGridPositions(const GridSizingData& sizingData)
1155 {
1156     m_columnPositions.resizeToFit(sizingData.columnTracks.size() + 1);
1157     m_columnPositions[0] = borderAndPaddingStart();
1158     for (size_t i = 0; i < m_columnPositions.size() - 1; ++i)
1159         m_columnPositions[i + 1] = m_columnPositions[i] + sizingData.columnTracks[i].m_usedBreadth;
1160
1161     m_rowPositions.resizeToFit(sizingData.rowTracks.size() + 1);
1162     m_rowPositions[0] = borderAndPaddingBefore();
1163     for (size_t i = 0; i < m_rowPositions.size() - 1; ++i)
1164         m_rowPositions[i + 1] = m_rowPositions[i] + sizingData.rowTracks[i].m_usedBreadth;
1165 }
1166
1167 LayoutPoint RenderGrid::findChildLogicalPosition(RenderBox* child, const GridSizingData& sizingData)
1168 {
1169     const GridCoordinate& coordinate = cachedGridCoordinate(child);
1170     ASSERT_UNUSED(sizingData, coordinate.columns.initialPositionIndex < sizingData.columnTracks.size());
1171     ASSERT_UNUSED(sizingData, coordinate.rows.initialPositionIndex < sizingData.rowTracks.size());
1172
1173     // The grid items should be inside the grid container's border box, that's why they need to be shifted.
1174     return LayoutPoint(m_columnPositions[coordinate.columns.initialPositionIndex] + marginStartForChild(*child), m_rowPositions[coordinate.rows.initialPositionIndex] + marginBeforeForChild(*child));
1175 }
1176
1177 void RenderGrid::paintChildren(PaintInfo& paintInfo, const LayoutPoint& paintOffset, PaintInfo& forChild, bool usePrintRect)
1178 {
1179     for (RenderBox* child = m_orderIterator.first(); child; child = m_orderIterator.next())
1180         paintChild(*child, paintInfo, paintOffset, forChild, usePrintRect);
1181 }
1182
1183 const char* RenderGrid::renderName() const
1184 {
1185     if (isFloating())
1186         return "RenderGrid (floating)";
1187     if (isOutOfFlowPositioned())
1188         return "RenderGrid (positioned)";
1189     if (isAnonymous())
1190         return "RenderGrid (generated)";
1191     if (isRelPositioned())
1192         return "RenderGrid (relative positioned)";
1193     return "RenderGrid";
1194 }
1195
1196 } // namespace WebCore
1197
1198 #endif /* ENABLE(CSS_GRID_LAYOUT) */