GridResolvedPosition GridResolvedPosition::resolveGridPositionFromStyle(const RenderStyle& 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 GridResolvedPosition::adjustGridPositionForSide(position.integerPosition() - 1, side);
size_t resolvedPosition = abs(position.integerPosition()) - 1;
const 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 GridResolvedPosition::adjustGridPositionForSide(endOfTrack - resolvedPosition, side);
}
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(!isNonExistentNamedLineOrArea(namedGridLine, gridContainerStyle, side));
const NamedGridLinesMap& gridLineNames = gridLinesForSide(gridContainerStyle, side);
auto implicitLine = gridLineNames.find(implicitNamedGridLineForSide(namedGridLine, side));
if (implicitLine != gridLineNames.end())
return GridResolvedPosition::adjustGridPositionForSide(implicitLine->value[0], side);
// Otherwise, if there is a named line with the specified name, contributes the first such line to the grid
// item's placement.
auto explicitLine = gridLineNames.find(namedGridLine);
if (explicitLine != gridLineNames.end())
return GridResolvedPosition::adjustGridPositionForSide(explicitLine->value[0], side);
// If none of the above works specs mandate us to treat it as auto BUT we should have detected it before calling
// this function in resolveGridPositionsFromStyle(). We should be covered anyway by the ASSERT at the beginning
// of this case block.
ASSERT_NOT_REACHED();
return 0;
}
case AutoPosition:
case SpanPosition:
// 'auto' and span depend on the opposite position for resolution (e.g. grid-row: auto / 1 or grid-column: span 3 / "myHeader").
ASSERT_NOT_REACHED();
return GridResolvedPosition(0);
}
ASSERT_NOT_REACHED();
return GridResolvedPosition(0);
}
PassOwnPtr<GridSpan> GridResolvedPosition::resolveNamedGridLinePositionAgainstOppositePosition(const RenderStyle& gridContainerStyle, const GridResolvedPosition& 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())
return GridSpan::create(resolvedOppositePosition, resolvedOppositePosition);
return GridSpan::createWithNamedSpanAgainstOpposite(resolvedOppositePosition, position, side, it->value);
}
GridResolvedPosition GridResolvedPosition::resolveNamedGridLinePositionFromStyle(const RenderStyle& gridContainerStyle, const GridPosition& position, GridPositionSide side)
{
ASSERT(!position.namedGridLine().isNull());
const NamedGridLinesMap& gridLinesNames = gridLinesForSide(gridContainerStyle, side);
NamedGridLinesMap::const_iterator it = gridLinesNames.find(position.namedGridLine());
if (it == gridLinesNames.end()) {
if (position.isPositive())
return GridResolvedPosition(0);
const size_t lastLine = explicitGridSizeForSide(gridContainerStyle, side);
return adjustGridPositionForSide(lastLine, side);
}
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 adjustGridPositionForSide(it->value[namedGridLineIndex], side);
}
static bool isNonExistentNamedLineOrArea(const String& lineName, const RenderStyle& style, GridPositionSide side)
{
const NamedGridLinesMap& gridLineNames = gridLinesForSide(style, side);
return !gridLineNames.contains(implicitNamedGridLineForSide(lineName, side)) && !gridLineNames.contains(lineName);
}
bool GridResolvedPosition::isValidNamedLineOrArea(const String& lineName, const ComputedStyle& style, GridPositionSide side)
{
const NamedGridLinesMap& gridLineNames = gridLinesForSide(style, side);
return gridLineNames.contains(implicitNamedGridLineForSide(lineName, side)) || gridLineNames.contains(lineName);
}
