C++ GridPosition::type方法代码示例

static int resolveGridPositionFromStyle(const RenderStyle& gridContainerStyle, const GridPosition& position, GridPositionSide side, unsigned autoRepeatTracksCount)
{
    switch (position.type()) {
    case ExplicitPosition: {
        ASSERT(position.integerPosition());

        if (!position.namedGridLine().isNull())
            return resolveNamedGridLinePositionFromStyle(gridContainerStyle, position, side, autoRepeatTracksCount);

        // Handle <integer> explicit position.
        if (position.isPositive())
            return position.integerPosition() - 1;

        unsigned resolvedPosition = std::abs(position.integerPosition()) - 1;
        const unsigned endOfTrack = explicitGridSizeForSide(gridContainerStyle, side, autoRepeatTracksCount);

        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(!position.namedGridLine().isNull());

        unsigned lastLine = explicitGridSizeForSide(gridContainerStyle, side, autoRepeatTracksCount);
        NamedLineCollection implicitLines(gridContainerStyle, implicitNamedGridLineForSide(namedGridLine, side), directionFromSide(side), lastLine, autoRepeatTracksCount);
        if (implicitLines.hasNamedLines())
            return implicitLines.firstPosition();

        // Otherwise, if there is a named line with the specified name, contributes the first such line to the grid
        // item's placement.
        NamedLineCollection explicitLines(gridContainerStyle, namedGridLine, directionFromSide(side), lastLine, autoRepeatTracksCount);
        if (explicitLines.hasNamedLines())
            return explicitLines.firstPosition();

        ASSERT(!NamedLineCollection::isValidNamedLineOrArea(namedGridLine, gridContainerStyle, side));
        // If none of the above works specs mandate to assume that all the lines in the implicit grid have this name.
        return lastLine + 1;
    }
    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 0;
    }
    ASSERT_NOT_REACHED();
    return 0;
}

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 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 GridResolvedPosition(0);

        return adjustGridPositionForSide(endOfTrack - resolvedPosition, side);
    }
    case NamedGridAreaPosition:
    {
        NamedGridAreaMap::const_iterator it = gridContainerStyle.namedGridArea().find(position.namedGridLine());
        // Unknown grid area should have been computed to 'auto' by now.
        ASSERT_WITH_SECURITY_IMPLICATION(it != gridContainerStyle.namedGridArea().end());
        const GridCoordinate& gridAreaCoordinate = it->value;
        switch (side) {
        case ColumnStartSide:
            return gridAreaCoordinate.columns.resolvedInitialPosition;
        case ColumnEndSide:
            return gridAreaCoordinate.columns.resolvedFinalPosition;
        case RowStartSide:
            return gridAreaCoordinate.rows.resolvedInitialPosition;
        case RowEndSide:
            return GridResolvedPosition(gridAreaCoordinate.rows.resolvedFinalPosition);
        }
        ASSERT_NOT_REACHED();
        return GridResolvedPosition(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);
}