[css-grid] Simplify the interface of GridResolvedPosition

third_party/WebKit/Source/core/layout/LayoutGrid.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1060 matching lines @@
 
     // We clear the dirty bit here as the grid sizes have been updated.
     m_gridIsDirty = false;
 
     Vector<LayoutBox*> autoMajorAxisAutoGridItems;
     Vector<LayoutBox*> specifiedMajorAxisAutoGridItems;
     for (LayoutBox* child = m_orderIterator.first(); child; child = m_orderIterator.next()) {
         if (child->isOutOfFlowPositioned())
             continue;
 
-        OwnPtr<GridSpan> rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForRows);
-        OwnPtr<GridSpan> columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForColumns);
-        if (!rowPositions || !columnPositions) {
-            GridSpan* majorAxisPositions = (autoPlacementMajorAxisDirection() == ForColumns) ? columnPositions.get() : rowPositions.get();
-            if (!majorAxisPositions)
+        auto unresolvedRowPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), *child, ForRows);
+        auto unresolvedColumnPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), *child, ForColumns);
+
+        if (unresolvedRowPositions.requiresAutoPlacement() || unresolvedColumnPositions.requiresAutoPlacement()) {
+            bool majorAxisDirectionIsForColumns = autoPlacementMajorAxisDirection() == ForColumns;
+            if ((majorAxisDirectionIsForColumns && unresolvedColumnPositions.requiresAutoPlacement())
+                || (!majorAxisDirectionIsForColumns && unresolvedRowPositions.requiresAutoPlacement()))
                 autoMajorAxisAutoGridItems.append(child);
             else
                 specifiedMajorAxisAutoGridItems.append(child);
             continue;
         }
-        insertItemIntoGrid(*child, GridCoordinate(*rowPositions, *columnPositions));
+        GridSpan rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedRowPositions, styleRef());
+        GridSpan columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedColumnPositions, styleRef());
+        insertItemIntoGrid(*child, GridCoordinate(rowPositions, columnPositions));
     }
 
     ASSERT(gridRowCount() >= GridResolvedPosition::explicitGridRowCount(*style()));
     ASSERT(gridColumnCount() >= GridResolvedPosition::explicitGridColumnCount(*style()));
 
     placeSpecifiedMajorAxisItemsOnGrid(specifiedMajorAxisAutoGridItems);
     placeAutoMajorAxisItemsOnGrid(autoMajorAxisAutoGridItems);
 
     m_grid.shrinkToFit();
 }
 
 void LayoutGrid::populateExplicitGridAndOrderIterator()
 {
     OrderIteratorPopulator populator(m_orderIterator);
 
     size_t maximumRowIndex = std::max<size_t>(1, GridResolvedPosition::explicitGridRowCount(*style()));
     size_t maximumColumnIndex = std::max<size_t>(1, GridResolvedPosition::explicitGridColumnCount(*style()));
 
     ASSERT(m_gridItemsIndexesMap.isEmpty());
     size_t childIndex = 0;
     for (LayoutBox* child = firstChildBox(); child; child = child->nextInFlowSiblingBox()) {
         if (child->isOutOfFlowPositioned())
             continue;
 
         populator.collectChild(child);
         m_gridItemsIndexesMap.set(child, childIndex++);
 
         // This function bypasses the cache (cachedGridCoordinate()) as it is used to build it.
-        OwnPtr<GridSpan> rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForRows);
-        OwnPtr<GridSpan> columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *child, ForColumns);
-
-        // |positions| is 0 if we need to run the auto-placement algorithm.
-        if (rowPositions) {
-            maximumRowIndex = std::max<size_t>(maximumRowIndex, rowPositions->resolvedFinalPosition.next().toInt());
+        auto unresolvedRowPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), *child, ForRows);
+        if (!unresolvedRowPositions.requiresAutoPlacement()) {
+            GridSpan rowPositions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedRowPositions, styleRef());
+            maximumRowIndex = std::max(maximumRowIndex, rowPositions.resolvedFinalPosition.next().toInt());
         } else {
             // Grow the grid for items with a definite row span, getting the largest such span.
-            GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *child, ForRows, GridResolvedPosition(0));
-            maximumRowIndex = std::max<size_t>(maximumRowIndex, positions.resolvedFinalPosition.next().toInt());
+            GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(styleRef(), *child, ForRows, GridResolvedPosition(0));
+            maximumRowIndex = std::max(maximumRowIndex, positions.resolvedFinalPosition.next().toInt());
         }
 
-        if (columnPositions) {
-            maximumColumnIndex = std::max<size_t>(maximumColumnIndex, columnPositions->resolvedFinalPosition.next().toInt());
+        auto unresolvedColumnPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), *child, ForColumns);
+        if (!unresolvedColumnPositions.requiresAutoPlacement()) {
+            GridSpan columnPositions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedColumnPositions, styleRef());
+            maximumColumnIndex = std::max(maximumColumnIndex, columnPositions.resolvedFinalPosition.next().toInt());
         } else {
             // Grow the grid for items with a definite column span, getting the largest such span.
-            GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *child, ForColumns, GridResolvedPosition(0));
-            maximumColumnIndex = std::max<size_t>(maximumColumnIndex, positions.resolvedFinalPosition.next().toInt());
+            GridSpan positions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(styleRef(), *child, ForColumns, GridResolvedPosition(0));
+            maximumColumnIndex = std::max(maximumColumnIndex, positions.resolvedFinalPosition.next().toInt());
         }
+
     }
 
     m_grid.grow(maximumRowIndex);
     for (auto& column : m_grid)
         column.grow(maximumColumnIndex);
 }
 
 PassOwnPtr<GridCoordinate> LayoutGrid::createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(const LayoutBox& gridItem, GridTrackSizingDirection specifiedDirection, const GridSpan& specifiedPositions) const
 {
     GridTrackSizingDirection crossDirection = specifiedDirection == ForColumns ? ForRows : ForColumns;
     const size_t endOfCrossDirection = crossDirection == ForColumns ? gridColumnCount() : gridRowCount();
     GridSpan crossDirectionPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), gridItem, crossDirection, GridResolvedPosition(endOfCrossDirection));
     return adoptPtr(new GridCoordinate(specifiedDirection == ForColumns ? crossDirectionPositions : specifiedPositions, specifiedDirection == ForColumns ? specifiedPositions : crossDirectionPositions));
 }
 
 void LayoutGrid::placeSpecifiedMajorAxisItemsOnGrid(const Vector<LayoutBox*>& autoGridItems)
 {
     bool isForColumns = autoPlacementMajorAxisDirection() == ForColumns;
     bool isGridAutoFlowDense = style()->isGridAutoFlowAlgorithmDense();
 
     // Mapping between the major axis tracks (rows or columns) and the last auto-placed item's position inserted on
     // that track. This is needed to implement "sparse" packing for items locked to a given track.
     // See http://dev.w3.org/csswg/css-grid/#auto-placement-algo
     HashMap<unsigned, unsigned, DefaultHash<unsigned>::Hash, WTF::UnsignedWithZeroKeyHashTraits<unsigned>> minorAxisCursors;
 
     for (const auto& autoGridItem : autoGridItems) {
-        OwnPtr<GridSpan> majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), *autoGridItem, autoPlacementMajorAxisDirection());
+        auto unresolvedMajorAxisPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), *autoGridItem, autoPlacementMajorAxisDirection());
+        ASSERT(!unresolvedMajorAxisPositions.requiresAutoPlacement());
+        GridSpan majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedMajorAxisPositions, styleRef());
         GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), *autoGridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
-        unsigned majorAxisInitialPosition = majorAxisPositions->resolvedInitialPosition.toInt();
+        unsigned majorAxisInitialPosition = majorAxisPositions.resolvedInitialPosition.toInt();
 
-        GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions->resolvedInitialPosition.toInt(), isGridAutoFlowDense ? 0 : minorAxisCursors.get(majorAxisInitialPosition));
-        OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions->integerSpan(), minorAxisPositions.integerSpan());
+        GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisPositions.resolvedInitialPosition.toInt(), isGridAutoFlowDense ? 0 : minorAxisCursors.get(majorAxisInitialPosition));
+        OwnPtr<GridCoordinate> emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions.integerSpan(), minorAxisPositions.integerSpan());
         if (!emptyGridArea)
-            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(*autoGridItem, autoPlacementMajorAxisDirection(), *majorAxisPositions);
+            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(*autoGridItem, autoPlacementMajorAxisDirection(), majorAxisPositions);
         insertItemIntoGrid(*autoGridItem, *emptyGridArea);
 
         if (!isGridAutoFlowDense)
             minorAxisCursors.set(majorAxisInitialPosition, isForColumns ? emptyGridArea->rows.resolvedInitialPosition.toInt() : emptyGridArea->columns.resolvedInitialPosition.toInt());
     }
 }
 
 void LayoutGrid::placeAutoMajorAxisItemsOnGrid(const Vector<LayoutBox*>& autoGridItems)
 {
     std::pair<size_t, size_t> autoPlacementCursor = std::make_pair(0, 0);
     bool isGridAutoFlowDense = style()->isGridAutoFlowAlgorithmDense();
 
     for (const auto& autoGridItem : autoGridItems) {
         placeAutoMajorAxisItemOnGrid(*autoGridItem, autoPlacementCursor);
 
         // If grid-auto-flow is dense, reset auto-placement cursor.
         if (isGridAutoFlowDense) {
             autoPlacementCursor.first = 0;
             autoPlacementCursor.second = 0;
         }
     }
 }
 
 void LayoutGrid::placeAutoMajorAxisItemOnGrid(LayoutBox& gridItem, std::pair<size_t, size_t>& autoPlacementCursor)
 {
-    OwnPtr<GridSpan> minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), gridItem, autoPlacementMinorAxisDirection());
-    ASSERT(!GridResolvedPosition::resolveGridPositionsFromStyle(*style(), gridItem, autoPlacementMajorAxisDirection()));
-    GridSpan majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), gridItem, autoPlacementMajorAxisDirection(), GridResolvedPosition(0));
+    ASSERT(GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), gridItem, autoPlacementMajorAxisDirection()).requiresAutoPlacement());
+    GridSpan majorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(styleRef(), gridItem, autoPlacementMajorAxisDirection(), GridResolvedPosition(0));
 
     const size_t endOfMajorAxis = (autoPlacementMajorAxisDirection() == ForColumns) ? gridColumnCount() : gridRowCount();
     size_t majorAxisAutoPlacementCursor = autoPlacementMajorAxisDirection() == ForColumns ? autoPlacementCursor.second : autoPlacementCursor.first;
     size_t minorAxisAutoPlacementCursor = autoPlacementMajorAxisDirection() == ForColumns ? autoPlacementCursor.first : autoPlacementCursor.second;
 
     OwnPtr<GridCoordinate> emptyGridArea;
-    if (minorAxisPositions) {
+    auto unresolvedMinorAxisPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), gridItem, autoPlacementMinorAxisDirection());
+    if (!unresolvedMinorAxisPositions.requiresAutoPlacement()) {
+        GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedMinorAxisPositions, styleRef());
+
         // Move to the next track in major axis if initial position in minor axis is before auto-placement cursor.
-        if (minorAxisPositions->resolvedInitialPosition.toInt() < minorAxisAutoPlacementCursor)
+        if (minorAxisPositions.resolvedInitialPosition.toInt() < minorAxisAutoPlacementCursor)
             majorAxisAutoPlacementCursor++;
 
         if (majorAxisAutoPlacementCursor < endOfMajorAxis) {
-            GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisPositions->resolvedInitialPosition.toInt(), majorAxisAutoPlacementCursor);
-            emptyGridArea = iterator.nextEmptyGridArea(minorAxisPositions->integerSpan(), majorAxisPositions.integerSpan());
+            GridIterator iterator(m_grid, autoPlacementMinorAxisDirection(), minorAxisPositions.resolvedInitialPosition.toInt(), majorAxisAutoPlacementCursor);
+            emptyGridArea = iterator.nextEmptyGridArea(minorAxisPositions.integerSpan(), majorAxisPositions.integerSpan());
         }
 
         if (!emptyGridArea)
-            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), *minorAxisPositions);
+            emptyGridArea = createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(gridItem, autoPlacementMinorAxisDirection(), minorAxisPositions);
     } else {
         GridSpan minorAxisPositions = GridResolvedPosition::resolveGridPositionsFromAutoPlacementPosition(*style(), gridItem, autoPlacementMinorAxisDirection(), GridResolvedPosition(0));
 
         for (size_t majorAxisIndex = majorAxisAutoPlacementCursor; majorAxisIndex < endOfMajorAxis; ++majorAxisIndex) {
             GridIterator iterator(m_grid, autoPlacementMajorAxisDirection(), majorAxisIndex, minorAxisAutoPlacementCursor);
             emptyGridArea = iterator.nextEmptyGridArea(majorAxisPositions.integerSpan(), minorAxisPositions.integerSpan());
 
             if (emptyGridArea) {
                 // Check that it fits in the minor axis direction, as we shouldn't grow in that direction here (it was already managed in populateExplicitGridAndOrderIterator()).
                 GridResolvedPosition minorAxisFinalPositionIndex = autoPlacementMinorAxisDirection() == ForColumns ? emptyGridArea->columns.resolvedFinalPosition : emptyGridArea->rows.resolvedFinalPosition;
@@ skipping 200 matching lines @@
         child->setExtraBlockOffset(rowOffset);
     }
 
     LayoutBlock::layoutPositionedObjects(relayoutChildren, info);
 }
 
 void LayoutGrid::offsetAndBreadthForPositionedChild(const LayoutBox& child, GridTrackSizingDirection direction, LayoutUnit& offset, LayoutUnit& breadth)
 {
     ASSERT(child.isHorizontalWritingMode() == isHorizontalWritingMode());
 
-    OwnPtr<GridSpan> positions = GridResolvedPosition::resolveGridPositionsFromStyle(*style(), child, direction);
-    if (!positions) {
-        offset = LayoutUnit();
+    auto unresolvedPositions = GridResolvedPosition::unresolvedSpanFromStyle(styleRef(), child, direction);
+    if (unresolvedPositions.requiresAutoPlacement()) {
+        offset = LayoutUnit(0);

[Manuel Rego, 2015/11/10 09:08:03]

Why LayoutUnit(0)?
We're using LayoutUnit() all over the place.

[svillar, 2015/11/10 10:56:37]

Yeah LayoutUnit() is more efficient, I thought it was the other way around.

         breadth = (direction == ForColumns) ? clientLogicalWidth() : clientLogicalHeight();
         return;
     }
 
-    GridPosition startPosition = (direction == ForColumns) ? child.style()->gridColumnStart() : child.style()->gridRowStart();
-    GridPosition endPosition = (direction == ForColumns) ? child.style()->gridColumnEnd() : child.style()->gridRowEnd();
-    size_t lastTrackIndex = (direction == ForColumns ? gridColumnCount() : gridRowCount()) - 1;
+    bool isForColumns = direction == ForColumns;
+    GridPosition startPosition = isForColumns ? child.style()->gridColumnStart() : child.style()->gridRowStart();
+    GridPosition endPosition = isForColumns ? child.style()->gridColumnEnd() : child.style()->gridRowEnd();
+    size_t lastTrackIndex = (isForColumns ? gridColumnCount() : gridRowCount()) - 1;
 
+    GridSpan positions = GridResolvedPosition::resolveGridPositionsFromStyle(unresolvedPositions, styleRef());
     bool startIsAuto = startPosition.isAuto()
-        || (startPosition.isNamedGridArea() && !GridResolvedPosition::isValidNamedLineOrArea(startPosition.namedGridLine(), styleRef(), GridResolvedPosition::initialPositionSide(direction)))
-        || (positions->resolvedInitialPosition.toInt() > lastTrackIndex);
+        || (startPosition.isNamedGridArea() && !GridResolvedPosition::isValidNamedLineOrArea(startPosition.namedGridLine(), styleRef(), isForColumns ? ColumnStartSide : RowStartSide))
+        || (positions.resolvedInitialPosition.toInt() > lastTrackIndex);
     bool endIsAuto = endPosition.isAuto()
-        || (endPosition.isNamedGridArea() && !GridResolvedPosition::isValidNamedLineOrArea(endPosition.namedGridLine(), styleRef(), GridResolvedPosition::finalPositionSide(direction)))
-        || (positions->resolvedFinalPosition.toInt() > lastTrackIndex);
+        || (endPosition.isNamedGridArea() && !GridResolvedPosition::isValidNamedLineOrArea(endPosition.namedGridLine(), styleRef(), isForColumns ? ColumnEndSide : RowEndSide))
+        || (positions.resolvedFinalPosition.toInt() > lastTrackIndex);
 
     GridResolvedPosition firstPosition = GridResolvedPosition(0);
-    GridResolvedPosition initialPosition = startIsAuto ? firstPosition : positions->resolvedInitialPosition;
+    GridResolvedPosition initialPosition = startIsAuto ? firstPosition : positions.resolvedInitialPosition;
     GridResolvedPosition lastPosition = GridResolvedPosition(lastTrackIndex);
-    GridResolvedPosition finalPosition = endIsAuto ? lastPosition : positions->resolvedFinalPosition;
+    GridResolvedPosition finalPosition = endIsAuto ? lastPosition : positions.resolvedFinalPosition;
 
     // Positioned children do not grow the grid, so we need to clamp the positions to avoid ending up outside of it.
     initialPosition = std::min<GridResolvedPosition>(initialPosition, lastPosition);
     finalPosition = std::min<GridResolvedPosition>(finalPosition, lastPosition);
 
     LayoutUnit start = startIsAuto ? LayoutUnit() : (direction == ForColumns) ?  m_columnPositions[initialPosition.toInt()] : m_rowPositions[initialPosition.toInt()];

[Manuel Rego, 2015/11/10 09:08:03]

Now that we've isForColumns we can keep using it here and the next line too.

[svillar, 2015/11/10 10:56:37]

Acknowledged.

     LayoutUnit end = endIsAuto ? (direction == ForColumns) ? logicalWidth() : logicalHeight() : (direction == ForColumns) ?  m_columnPositions[finalPosition.next().toInt()] : m_rowPositions[finalPosition.next().toInt()];
 
     breadth = end - start;
 
     if (startIsAuto)
         breadth -= (direction == ForColumns) ? borderStart() : borderBefore();
     else
         start -= ((direction == ForColumns) ? borderStart() : borderBefore());
 
     if (endIsAuto) {
@@ skipping 537 matching lines @@
 
     return LayoutPoint(rowAxisOffset, columnAxisOffsetForChild(child));
 }
 
 void LayoutGrid::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
 {
     GridPainter(*this).paintChildren(paintInfo, paintOffset);
 }
 
 } // namespace blink