[css-grid] Initial support for implicit grid before explicit grid

third_party/WebKit/Source/core/style/GridResolvedPosition.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/style/GridResolvedPosition.h"
 
 #include "core/layout/LayoutBox.h"
 #include "core/style/GridCoordinate.h"
 
@@ skipping 47 matching lines @@
     // If the grid item has an automatic position and a grid span for a named line in a given dimension, instead treat the grid span as one.
     if (initialPosition.isAuto() && finalPosition.isSpan() && !finalPosition.namedGridLine().isNull())
         finalPosition.setSpanPosition(1, String());
     if (finalPosition.isAuto() && initialPosition.isSpan() && !initialPosition.namedGridLine().isNull())
         initialPosition.setSpanPosition(1, String());
 }
 
 static GridSpan definiteGridSpanWithInitialNamedSpanAgainstOpposite(size_t resolvedOppositePosition, const GridPosition& position, const Vector<size_t>& gridLines)
 {
     if (resolvedOppositePosition == 0)
-        return GridSpan::definiteGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
+        return GridSpan::untranslatedGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
 
     size_t firstLineBeforeOppositePositionIndex = 0;
     const size_t* firstLineBeforeOppositePosition = std::lower_bound(gridLines.begin(), gridLines.end(), resolvedOppositePosition);
     if (firstLineBeforeOppositePosition != gridLines.end())
         firstLineBeforeOppositePositionIndex = firstLineBeforeOppositePosition - gridLines.begin();
     size_t gridLineIndex = std::max<int>(0, firstLineBeforeOppositePositionIndex - position.spanPosition());
     size_t resolvedGridLinePosition = gridLines[gridLineIndex];
     if (resolvedGridLinePosition >= resolvedOppositePosition)
         resolvedGridLinePosition = resolvedOppositePosition - 1;
-    return GridSpan::definiteGridSpan(resolvedGridLinePosition, resolvedOppositePosition);
+    return GridSpan::untranslatedGridSpan(resolvedGridLinePosition, resolvedOppositePosition);
 }
 
 static GridSpan definiteGridSpanWithFinalNamedSpanAgainstOpposite(size_t resolvedOppositePosition, const GridPosition& position, const Vector<size_t>& gridLines)
 {
     ASSERT(gridLines.size());
     size_t firstLineAfterOppositePositionIndex = gridLines.size() - 1;
     const size_t* firstLineAfterOppositePosition = std::upper_bound(gridLines.begin(), gridLines.end(), resolvedOppositePosition);
     if (firstLineAfterOppositePosition != gridLines.end())
         firstLineAfterOppositePositionIndex = firstLineAfterOppositePosition - gridLines.begin();
     size_t gridLineIndex = std::min(gridLines.size() - 1, firstLineAfterOppositePositionIndex + position.spanPosition() - 1);
     size_t resolvedGridLinePosition = gridLines[gridLineIndex];
     if (resolvedGridLinePosition <= resolvedOppositePosition)
         resolvedGridLinePosition = resolvedOppositePosition + 1;
 
-    return GridSpan::definiteGridSpan(resolvedOppositePosition, resolvedGridLinePosition);
+    return GridSpan::untranslatedGridSpan(resolvedOppositePosition, resolvedGridLinePosition);
 }
 
 static GridSpan definiteGridSpanWithNamedSpanAgainstOpposite(size_t resolvedOppositePosition, const GridPosition& position, GridPositionSide side, const Vector<size_t>& gridLines)
 {
     if (side == RowStartSide || side == ColumnStartSide)
         return definiteGridSpanWithInitialNamedSpanAgainstOpposite(resolvedOppositePosition, position, gridLines);
 
     return definiteGridSpanWithFinalNamedSpanAgainstOpposite(resolvedOppositePosition, position, gridLines);
 }
 
 static GridSpan resolveNamedGridLinePositionAgainstOppositePosition(const ComputedStyle& gridContainerStyle, size_t resolvedOppositePosition, const GridPosition& position, GridPositionSide side)
 {
     ASSERT(position.isSpan());
     ASSERT(!position.namedGridLine().isNull());
     // Negative positions are not allowed per the specification and should have been handled during parsing.
     ASSERT(position.spanPosition() > 0);
 
     const NamedGridLinesMap& gridLinesNames = gridLinesForSide(gridContainerStyle, side);
     NamedGridLinesMap::const_iterator it = gridLinesNames.find(position.namedGridLine());
 
     // 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).
     // See http://lists.w3.org/Archives/Public/www-style/2013Jun/0394.html.
     if (it == gridLinesNames.end()) {
         if ((side == ColumnStartSide || side == RowStartSide) && resolvedOppositePosition)
-            return GridSpan::definiteGridSpan(resolvedOppositePosition - 1, resolvedOppositePosition);
-        return GridSpan::definiteGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
+            return GridSpan::untranslatedGridSpan(resolvedOppositePosition - 1, resolvedOppositePosition);
+        return GridSpan::untranslatedGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
     }
 
     return definiteGridSpanWithNamedSpanAgainstOpposite(resolvedOppositePosition, position, side, it->value);
 }
 
 static GridSpan definiteGridSpanWithSpanAgainstOpposite(size_t resolvedOppositePosition, const GridPosition& position, GridPositionSide side)
 {
     size_t positionOffset = position.spanPosition();
-    if (side == ColumnStartSide || side == RowStartSide) {
-        if (resolvedOppositePosition == 0)
-            return GridSpan::definiteGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
+    if (side == ColumnStartSide || side == RowStartSide)
+        return GridSpan::untranslatedGridSpan(resolvedOppositePosition - positionOffset, resolvedOppositePosition);

[jfernandez, 2015/12/18 14:33:21]

Are we handling here the case where resolvedOppositePosition is zero ? 

[Manuel Rego, 2015/12/18 22:42:30]

Precisely now we support negative values, so we don't care.

If resolvedOppositePosition is "0" and positionOffset is "2"
we simply return GridSpan(-2, 0).

 
-        size_t initialResolvedPosition = std::max<int>(0, resolvedOppositePosition - positionOffset);
-        return GridSpan::definiteGridSpan(initialResolvedPosition, resolvedOppositePosition);
-    }
-
-    return GridSpan::definiteGridSpan(resolvedOppositePosition, resolvedOppositePosition + positionOffset);
+    return GridSpan::untranslatedGridSpan(resolvedOppositePosition, resolvedOppositePosition + positionOffset);
 }
 
 static GridSpan resolveGridPositionAgainstOppositePosition(const ComputedStyle& gridContainerStyle, size_t resolvedOppositePosition, const GridPosition& position, GridPositionSide side)
 {
     if (position.isAuto()) {
-        if ((side == ColumnStartSide || side == RowStartSide) && resolvedOppositePosition)
-            return GridSpan::definiteGridSpan(resolvedOppositePosition - 1, resolvedOppositePosition);
-        return GridSpan::definiteGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
+        if (side == ColumnStartSide || side == RowStartSide)
+            return GridSpan::untranslatedGridSpan(resolvedOppositePosition - 1, resolvedOppositePosition);
+        return GridSpan::untranslatedGridSpan(resolvedOppositePosition, resolvedOppositePosition + 1);
     }
 
     ASSERT(position.isSpan());
     ASSERT(position.spanPosition() > 0);
 
     if (!position.namedGridLine().isNull()) {
         // span 2 'c' -> we need to find the appropriate grid line before / after our opposite position.
         return resolveNamedGridLinePositionAgainstOppositePosition(gridContainerStyle, resolvedOppositePosition, position, side);
     }
 
@@ skipping 46 matching lines @@
     }
 
     size_t namedGridLineIndex;
     if (position.isPositive())
         namedGridLineIndex = std::min<size_t>(position.integerPosition(), it->value.size()) - 1;
     else
         namedGridLineIndex = std::max<int>(it->value.size() - abs(position.integerPosition()), 0);
     return it->value[namedGridLineIndex];
 }
 
-static size_t resolveGridPositionFromStyle(const ComputedStyle& gridContainerStyle, const GridPosition& position, GridPositionSide side)
+static int resolveGridPositionFromStyle(const ComputedStyle& gridContainerStyle, const GridPosition& position, GridPositionSide side)
 {
     switch (position.type()) {
     case ExplicitPosition: {
         ASSERT(position.integerPosition());
 
         if (!position.namedGridLine().isNull())
             return resolveNamedGridLinePositionFromStyle(gridContainerStyle, position, side);
 
         // Handle <integer> explicit position.
         if (position.isPositive())
             return position.integerPosition() - 1;
 
         size_t resolvedPosition = abs(position.integerPosition()) - 1;
         size_t endOfTrack = explicitGridSizeForSide(gridContainerStyle, side);
 
-        // Per http://lists.w3.org/Archives/Public/www-style/2013Mar/0589.html, we clamp negative value to the first line.
-        if (endOfTrack < resolvedPosition)
-            return 0;
-
         return endOfTrack - resolvedPosition;
     }
     case NamedGridAreaPosition:
     {
         // First attempt to match the grid area's edge to a named grid area: if there is a named line with the name
         // ''<custom-ident>-start (for grid-*-start) / <custom-ident>-end'' (for grid-*-end), contributes the first such
         // line to the grid item's placement.
         String namedGridLine = position.namedGridLine();
         ASSERT(GridResolvedPosition::isValidNamedLineOrArea(namedGridLine, gridContainerStyle, side));
 
@@ skipping 32 matching lines @@
     GridPositionSide initialSide = initialPositionSide(direction);
     GridPositionSide finalSide = finalPositionSide(direction);
 
     if (initialPosition.shouldBeResolvedAgainstOppositePosition() && finalPosition.shouldBeResolvedAgainstOppositePosition()) {
         // We can't get our grid positions without running the auto placement algorithm.
         return GridSpan::indefiniteGridSpan();
     }
 
     if (initialPosition.shouldBeResolvedAgainstOppositePosition()) {
         // Infer the position from the final position ('auto / 1' or 'span 2 / 3' case).
-        size_t finalResolvedPosition = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
+        int finalResolvedPosition = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
         return resolveGridPositionAgainstOppositePosition(gridContainerStyle, finalResolvedPosition, initialPosition, initialSide);
     }
 
     if (finalPosition.shouldBeResolvedAgainstOppositePosition()) {
         // Infer our position from the initial position ('1 / auto' or '3 / span 2' case).
-        size_t initialResolvedPosition = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
+        int initialResolvedPosition = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
         return resolveGridPositionAgainstOppositePosition(gridContainerStyle, initialResolvedPosition, finalPosition, finalSide);
     }
 
-    size_t resolvedInitialPosition = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
-    size_t resolvedFinalPosition = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
+    int resolvedInitialPosition = resolveGridPositionFromStyle(gridContainerStyle, initialPosition, initialSide);
+    int resolvedFinalPosition = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, finalSide);
 
     if (resolvedFinalPosition < resolvedInitialPosition)
         std::swap(resolvedFinalPosition, resolvedInitialPosition);
     else if (resolvedFinalPosition == resolvedInitialPosition)
         resolvedFinalPosition = resolvedInitialPosition + 1;
 
-    return GridSpan::definiteGridSpan(resolvedInitialPosition, resolvedFinalPosition);
+    return GridSpan::untranslatedGridSpan(resolvedInitialPosition, resolvedFinalPosition);
 }
 
 } // namespace blink