[css-grid] Simplify the interface of GridResolvedPosition

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

Index: third_party/WebKit/Source/core/layout/LayoutGrid.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutGrid.cpp b/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
index bd5b96d4193f6ac6ae180422949f5be4e4a1a39c..06cffa9972f6acc61bad61187ddbe3a625f024bf 100644
--- a/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
@@ -1078,17 +1078,21 @@ void LayoutGrid::placeItemsOnGrid()
         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()));
@@ -1117,25 +1121,26 @@ void LayoutGrid::populateExplicitGridAndOrderIterator()
         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);
@@ -1162,14 +1167,16 @@ void LayoutGrid::placeSpecifiedMajorAxisItemsOnGrid(const Vector<LayoutBox*>& au
     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)
@@ -1195,27 +1202,29 @@ void LayoutGrid::placeAutoMajorAxisItemsOnGrid(const Vector<LayoutBox*>& autoGri
 
 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));
 
@@ -1436,28 +1445,30 @@ void LayoutGrid::offsetAndBreadthForPositionedChild(const LayoutBox& child, Grid
 {
     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);