| // 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 "GridPositionsResolver.h" |
| |
| #include "core/layout/LayoutBox.h" |
| #include "core/style/GridArea.h" |
| #include <algorithm> |
| |
| namespace blink { |
| |
| static inline GridTrackSizingDirection directionFromSide( |
| GridPositionSide side) { |
| return side == ColumnStartSide || side == ColumnEndSide ? ForColumns |
| : ForRows; |
| } |
| |
| static inline String implicitNamedGridLineForSide(const String& lineName, |
| GridPositionSide side) { |
| return lineName + ((side == ColumnStartSide || side == RowStartSide) |
| ? "-start" |
| : "-end"); |
| } |
| |
| NamedLineCollection::NamedLineCollection( |
| const ComputedStyle& gridContainerStyle, |
| const String& namedLine, |
| GridTrackSizingDirection direction, |
| size_t lastLine, |
| size_t autoRepeatTracksCount) |
| : m_lastLine(lastLine), m_autoRepeatTotalTracks(autoRepeatTracksCount) { |
| bool isRowAxis = direction == ForColumns; |
| const NamedGridLinesMap& gridLineNames = |
| isRowAxis ? gridContainerStyle.namedGridColumnLines() |
| : gridContainerStyle.namedGridRowLines(); |
| const NamedGridLinesMap& autoRepeatGridLineNames = |
| isRowAxis ? gridContainerStyle.autoRepeatNamedGridColumnLines() |
| : gridContainerStyle.autoRepeatNamedGridRowLines(); |
| |
| if (!gridLineNames.isEmpty()) { |
| auto it = gridLineNames.find(namedLine); |
| m_namedLinesIndexes = it == gridLineNames.end() ? nullptr : &it->value; |
| } |
| |
| if (!autoRepeatGridLineNames.isEmpty()) { |
| auto it = autoRepeatGridLineNames.find(namedLine); |
| m_autoRepeatNamedLinesIndexes = |
| it == autoRepeatGridLineNames.end() ? nullptr : &it->value; |
| } |
| |
| m_insertionPoint = |
| isRowAxis ? gridContainerStyle.gridAutoRepeatColumnsInsertionPoint() |
| : gridContainerStyle.gridAutoRepeatRowsInsertionPoint(); |
| |
| m_autoRepeatTrackListLength = |
| isRowAxis ? gridContainerStyle.gridAutoRepeatColumns().size() |
| : gridContainerStyle.gridAutoRepeatRows().size(); |
| } |
| |
| bool NamedLineCollection::isValidNamedLineOrArea( |
| const String& namedLine, |
| const ComputedStyle& gridContainerStyle, |
| GridPositionSide side) { |
| bool isRowAxis = directionFromSide(side) == ForColumns; |
| const NamedGridLinesMap& gridLineNames = |
| isRowAxis ? gridContainerStyle.namedGridColumnLines() |
| : gridContainerStyle.namedGridRowLines(); |
| const NamedGridLinesMap& autoRepeatGridLineNames = |
| isRowAxis ? gridContainerStyle.autoRepeatNamedGridColumnLines() |
| : gridContainerStyle.autoRepeatNamedGridRowLines(); |
| |
| if (gridLineNames.contains(namedLine) || |
| autoRepeatGridLineNames.contains(namedLine)) |
| return true; |
| |
| String implicitName = implicitNamedGridLineForSide(namedLine, side); |
| return gridLineNames.contains(implicitName) || |
| autoRepeatGridLineNames.contains(implicitName); |
| } |
| |
| bool NamedLineCollection::hasNamedLines() { |
| return m_namedLinesIndexes || m_autoRepeatNamedLinesIndexes; |
| } |
| |
| size_t NamedLineCollection::find(size_t line) { |
| if (line > m_lastLine) |
| return kNotFound; |
| |
| if (!m_autoRepeatNamedLinesIndexes || line < m_insertionPoint) |
| return m_namedLinesIndexes ? m_namedLinesIndexes->find(line) : kNotFound; |
| |
| if (line <= (m_insertionPoint + m_autoRepeatTotalTracks)) { |
| size_t localIndex = line - m_insertionPoint; |
| |
| size_t indexInFirstRepetition = localIndex % m_autoRepeatTrackListLength; |
| if (indexInFirstRepetition) |
| return m_autoRepeatNamedLinesIndexes->find(indexInFirstRepetition); |
| |
| // The line names defined in the last line are also present in the first |
| // line of the next repetition (if any). Same for the line names defined in |
| // the first line. |
| if (localIndex == m_autoRepeatTotalTracks) |
| return m_autoRepeatNamedLinesIndexes->find(m_autoRepeatTrackListLength); |
| size_t position = |
| m_autoRepeatNamedLinesIndexes->find(static_cast<size_t>(0)); |
| if (position != kNotFound) |
| return position; |
| return localIndex == 0 ? kNotFound |
| : m_autoRepeatNamedLinesIndexes->find( |
| m_autoRepeatTrackListLength); |
| } |
| |
| return m_namedLinesIndexes |
| ? m_namedLinesIndexes->find(line - (m_autoRepeatTotalTracks - 1)) |
| : kNotFound; |
| } |
| |
| bool NamedLineCollection::contains(size_t line) { |
| CHECK(hasNamedLines()); |
| return find(line) != kNotFound; |
| } |
| |
| size_t NamedLineCollection::firstPosition() { |
| CHECK(hasNamedLines()); |
| |
| size_t firstLine = 0; |
| |
| if (!m_autoRepeatNamedLinesIndexes) { |
| if (m_insertionPoint == 0 || |
| m_insertionPoint < m_namedLinesIndexes->at(firstLine)) |
| return m_namedLinesIndexes->at(firstLine) + |
| (m_autoRepeatTotalTracks ? m_autoRepeatTotalTracks - 1 : 0); |
| return m_namedLinesIndexes->at(firstLine); |
| } |
| |
| if (!m_namedLinesIndexes) |
| return m_autoRepeatNamedLinesIndexes->at(firstLine) + m_insertionPoint; |
| |
| if (m_insertionPoint == 0) |
| return std::min( |
| m_namedLinesIndexes->at(firstLine) + m_autoRepeatTotalTracks, |
| m_autoRepeatNamedLinesIndexes->at(firstLine)); |
| |
| return std::min( |
| m_namedLinesIndexes->at(firstLine), |
| m_autoRepeatNamedLinesIndexes->at(firstLine) + m_insertionPoint); |
| } |
| |
| GridPositionSide GridPositionsResolver::initialPositionSide( |
| GridTrackSizingDirection direction) { |
| return (direction == ForColumns) ? ColumnStartSide : RowStartSide; |
| } |
| |
| GridPositionSide GridPositionsResolver::finalPositionSide( |
| GridTrackSizingDirection direction) { |
| return (direction == ForColumns) ? ColumnEndSide : RowEndSide; |
| } |
| |
| static void initialAndFinalPositionsFromStyle( |
| const ComputedStyle& gridContainerStyle, |
| const LayoutBox& gridItem, |
| GridTrackSizingDirection direction, |
| GridPosition& initialPosition, |
| GridPosition& finalPosition) { |
| initialPosition = (direction == ForColumns) |
| ? gridItem.style()->gridColumnStart() |
| : gridItem.style()->gridRowStart(); |
| finalPosition = (direction == ForColumns) ? gridItem.style()->gridColumnEnd() |
| : gridItem.style()->gridRowEnd(); |
| |
| // We must handle the placement error handling code here instead of in the |
| // StyleAdjuster because we don't want to overwrite the specified values. |
| if (initialPosition.isSpan() && finalPosition.isSpan()) |
| finalPosition.setAutoPosition(); |
| |
| if (gridItem.isOutOfFlowPositioned()) { |
| // Early detect the case of non existing named grid lines for positioned |
| // items. |
| if (initialPosition.isNamedGridArea() && |
| !NamedLineCollection::isValidNamedLineOrArea( |
| initialPosition.namedGridLine(), gridContainerStyle, |
| GridPositionsResolver::initialPositionSide(direction))) |
| initialPosition.setAutoPosition(); |
| |
| if (finalPosition.isNamedGridArea() && |
| !NamedLineCollection::isValidNamedLineOrArea( |
| finalPosition.namedGridLine(), gridContainerStyle, |
| GridPositionsResolver::finalPositionSide(direction))) |
| finalPosition.setAutoPosition(); |
| } |
| |
| // 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, nullAtom); |
| if (finalPosition.isAuto() && initialPosition.isSpan() && |
| !initialPosition.namedGridLine().isNull()) |
| initialPosition.setSpanPosition(1, nullAtom); |
| } |
| |
| static size_t lookAheadForNamedGridLine(int start, |
| size_t numberOfLines, |
| size_t gridLastLine, |
| NamedLineCollection& linesCollection) { |
| ASSERT(numberOfLines); |
| |
| // Only implicit lines on the search direction are assumed to have the given |
| // name, so we can start to look from first line. |
| // See: https://drafts.csswg.org/css-grid/#grid-placement-span-int |
| size_t end = std::max(start, 0); |
| |
| if (!linesCollection.hasNamedLines()) { |
| end = std::max(end, gridLastLine + 1); |
| return end + numberOfLines - 1; |
| } |
| |
| for (; numberOfLines; ++end) { |
| if (end > gridLastLine || linesCollection.contains(end)) |
| numberOfLines--; |
| } |
| |
| ASSERT(end); |
| return end - 1; |
| } |
| |
| static int lookBackForNamedGridLine(int end, |
| size_t numberOfLines, |
| int gridLastLine, |
| NamedLineCollection& linesCollection) { |
| ASSERT(numberOfLines); |
| |
| // Only implicit lines on the search direction are assumed to have the given |
| // name, so we can start to look from last line. |
| // See: https://drafts.csswg.org/css-grid/#grid-placement-span-int |
| int start = std::min(end, gridLastLine); |
| |
| if (!linesCollection.hasNamedLines()) { |
| start = std::min(start, -1); |
| return start - numberOfLines + 1; |
| } |
| |
| for (; numberOfLines; --start) { |
| if (start < 0 || linesCollection.contains(start)) |
| numberOfLines--; |
| } |
| |
| return start + 1; |
| } |
| |
| static GridSpan definiteGridSpanWithNamedSpanAgainstOpposite( |
| int oppositeLine, |
| const GridPosition& position, |
| GridPositionSide side, |
| int lastLine, |
| NamedLineCollection& linesCollection) { |
| int start, end; |
| if (side == RowStartSide || side == ColumnStartSide) { |
| start = lookBackForNamedGridLine(oppositeLine - 1, position.spanPosition(), |
| lastLine, linesCollection); |
| end = oppositeLine; |
| } else { |
| start = oppositeLine; |
| end = lookAheadForNamedGridLine(oppositeLine + 1, position.spanPosition(), |
| lastLine, linesCollection); |
| } |
| |
| return GridSpan::untranslatedDefiniteGridSpan(start, end); |
| } |
| |
| size_t GridPositionsResolver::explicitGridColumnCount( |
| const ComputedStyle& gridContainerStyle, |
| size_t autoRepeatTracksCount) { |
| return std::min<size_t>( |
| std::max(gridContainerStyle.gridTemplateColumns().size() + |
| autoRepeatTracksCount, |
| gridContainerStyle.namedGridAreaColumnCount()), |
| kGridMaxTracks); |
| } |
| |
| size_t GridPositionsResolver::explicitGridRowCount( |
| const ComputedStyle& gridContainerStyle, |
| size_t autoRepeatTracksCount) { |
| return std::min<size_t>( |
| std::max( |
| gridContainerStyle.gridTemplateRows().size() + autoRepeatTracksCount, |
| gridContainerStyle.namedGridAreaRowCount()), |
| kGridMaxTracks); |
| } |
| |
| static size_t explicitGridSizeForSide(const ComputedStyle& gridContainerStyle, |
| GridPositionSide side, |
| size_t autoRepeatTracksCount) { |
| return (side == ColumnStartSide || side == ColumnEndSide) |
| ? GridPositionsResolver::explicitGridColumnCount( |
| gridContainerStyle, autoRepeatTracksCount) |
| : GridPositionsResolver::explicitGridRowCount( |
| gridContainerStyle, autoRepeatTracksCount); |
| } |
| |
| static GridSpan resolveNamedGridLinePositionAgainstOppositePosition( |
| const ComputedStyle& gridContainerStyle, |
| int oppositeLine, |
| const GridPosition& position, |
| size_t autoRepeatTracksCount, |
| 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); |
| |
| size_t lastLine = |
| explicitGridSizeForSide(gridContainerStyle, side, autoRepeatTracksCount); |
| NamedLineCollection linesCollection( |
| gridContainerStyle, position.namedGridLine(), directionFromSide(side), |
| lastLine, autoRepeatTracksCount); |
| return definiteGridSpanWithNamedSpanAgainstOpposite( |
| oppositeLine, position, side, lastLine, linesCollection); |
| } |
| |
| static GridSpan definiteGridSpanWithSpanAgainstOpposite( |
| int oppositeLine, |
| const GridPosition& position, |
| GridPositionSide side) { |
| size_t positionOffset = position.spanPosition(); |
| if (side == ColumnStartSide || side == RowStartSide) |
| return GridSpan::untranslatedDefiniteGridSpan(oppositeLine - positionOffset, |
| oppositeLine); |
| |
| return GridSpan::untranslatedDefiniteGridSpan(oppositeLine, |
| oppositeLine + positionOffset); |
| } |
| |
| static GridSpan resolveGridPositionAgainstOppositePosition( |
| const ComputedStyle& gridContainerStyle, |
| int oppositeLine, |
| const GridPosition& position, |
| GridPositionSide side, |
| size_t autoRepeatTracksCount) { |
| if (position.isAuto()) { |
| if (side == ColumnStartSide || side == RowStartSide) |
| return GridSpan::untranslatedDefiniteGridSpan(oppositeLine - 1, |
| oppositeLine); |
| return GridSpan::untranslatedDefiniteGridSpan(oppositeLine, |
| oppositeLine + 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, oppositeLine, position, autoRepeatTracksCount, |
| side); |
| } |
| |
| return definiteGridSpanWithSpanAgainstOpposite(oppositeLine, position, side); |
| } |
| |
| size_t GridPositionsResolver::spanSizeForAutoPlacedItem( |
| const ComputedStyle& gridContainerStyle, |
| const LayoutBox& gridItem, |
| GridTrackSizingDirection direction) { |
| GridPosition initialPosition, finalPosition; |
| initialAndFinalPositionsFromStyle(gridContainerStyle, gridItem, direction, |
| initialPosition, finalPosition); |
| |
| // This method will only be used when both positions need to be resolved |
| // against the opposite one. |
| ASSERT(initialPosition.shouldBeResolvedAgainstOppositePosition() && |
| finalPosition.shouldBeResolvedAgainstOppositePosition()); |
| |
| if (initialPosition.isAuto() && finalPosition.isAuto()) |
| return 1; |
| |
| GridPosition position = |
| initialPosition.isSpan() ? initialPosition : finalPosition; |
| ASSERT(position.isSpan()); |
| ASSERT(position.spanPosition()); |
| return position.spanPosition(); |
| } |
| |
| static int resolveNamedGridLinePositionFromStyle( |
| const ComputedStyle& gridContainerStyle, |
| const GridPosition& position, |
| GridPositionSide side, |
| size_t autoRepeatTracksCount) { |
| ASSERT(!position.namedGridLine().isNull()); |
| |
| size_t lastLine = |
| explicitGridSizeForSide(gridContainerStyle, side, autoRepeatTracksCount); |
| NamedLineCollection linesCollection( |
| gridContainerStyle, position.namedGridLine(), directionFromSide(side), |
| lastLine, autoRepeatTracksCount); |
| |
| if (position.isPositive()) |
| return lookAheadForNamedGridLine(0, abs(position.integerPosition()), |
| lastLine, linesCollection); |
| |
| return lookBackForNamedGridLine(lastLine, abs(position.integerPosition()), |
| lastLine, linesCollection); |
| } |
| |
| static int resolveGridPositionFromStyle(const ComputedStyle& gridContainerStyle, |
| const GridPosition& position, |
| GridPositionSide side, |
| size_t 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; |
| |
| size_t resolvedPosition = abs(position.integerPosition()) - 1; |
| size_t 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()); |
| |
| size_t 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; |
| } |
| |
| GridSpan GridPositionsResolver::resolveGridPositionsFromStyle( |
| const ComputedStyle& gridContainerStyle, |
| const LayoutBox& gridItem, |
| GridTrackSizingDirection direction, |
| size_t autoRepeatTracksCount) { |
| GridPosition initialPosition, finalPosition; |
| initialAndFinalPositionsFromStyle(gridContainerStyle, gridItem, direction, |
| initialPosition, finalPosition); |
| |
| 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). |
| int endLine = resolveGridPositionFromStyle( |
| gridContainerStyle, finalPosition, finalSide, autoRepeatTracksCount); |
| return resolveGridPositionAgainstOppositePosition( |
| gridContainerStyle, endLine, initialPosition, initialSide, |
| autoRepeatTracksCount); |
| } |
| |
| if (finalPosition.shouldBeResolvedAgainstOppositePosition()) { |
| // Infer our position from the initial position ('1 / auto' or '3 / span 2' |
| // case). |
| int startLine = |
| resolveGridPositionFromStyle(gridContainerStyle, initialPosition, |
| initialSide, autoRepeatTracksCount); |
| return resolveGridPositionAgainstOppositePosition( |
| gridContainerStyle, startLine, finalPosition, finalSide, |
| autoRepeatTracksCount); |
| } |
| |
| int startLine = resolveGridPositionFromStyle( |
| gridContainerStyle, initialPosition, initialSide, autoRepeatTracksCount); |
| int endLine = resolveGridPositionFromStyle(gridContainerStyle, finalPosition, |
| finalSide, autoRepeatTracksCount); |
| |
| if (endLine < startLine) |
| std::swap(endLine, startLine); |
| else if (endLine == startLine) |
| endLine = startLine + 1; |
| |
| return GridSpan::untranslatedDefiniteGridSpan(startLine, endLine); |
| } |
| |
| } // namespace blink |
