Source/WebCore/rendering/RenderGrid.h

/*
 * Copyright (C) 2011, 2022 Apple Inc. All rights reserved.
 * Copyright (C) 2013-2017 Igalia S.L.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#pragma once

#include "Grid.h"
#include "GridTrackSizingAlgorithm.h"
#include "RenderBlock.h"
#include "StyleGridTrackSizingDirection.h"
#include <wtf/TZoneMalloc.h>

namespace WTF {
template<typename T>
class Range;
}

namespace WebCore {

namespace LayoutIntegration {
class GridLayout;
}

class GridArea;
class RenderGridLayoutState;
class GridLanesLayout;
class GridLanesResult;
class GridSpan;
class LayoutRange;

// The result of a grid lanes placement only exists for the duration of a single layout (or intrinsic
// width computation) of a grid lanes container, so it is threaded through the layout call chain as a
// non-owning reference rather than living on the renderer. It is std::nullopt for grids which are
// not performing a grid lanes layout.
using GridLanesResultRef = std::optional<std::reference_wrapper<const GridLanesResult>>;

struct ContentAlignmentData {
    LayoutUnit positionOffset;
    LayoutUnit distributionOffset;
};

enum class GridAxisPosition : uint8_t { GridAxisStart, GridAxisEnd, GridAxisCenter };

enum class SubgridDidChange : bool { No, Yes };

class GridItemSizeCache {
public:
    void setSizeForGridItem(const RenderBox& gridItem, LayoutUnit size);
    std::optional<LayoutUnit> NODELETE sizeForItem(const RenderBox& gridItem) const;
    void invalidateSizeForItem(const RenderBox& gridItem);

private:
    SingleThreadWeakHashMap<const RenderBox, std::optional<LayoutUnit>> m_sizes;
};

class RenderGrid final : public RenderBlock {
    WTF_MAKE_TZONE_ALLOCATED(RenderGrid);
    WTF_OVERRIDE_DELETE_FOR_CHECKED_PTR(RenderGrid);
public:
    RenderGrid(Element&, Style::ComputedStyle&&);
    virtual ~RenderGrid();

    Element& element() const { return downcast<Element>(nodeForNonAnonymous()); }

    void styleDidChange(Style::Difference, const Style::ComputedStyle* oldStyle) override;
    void layoutBlock(RelayoutChildren, LayoutUnit pageLogicalHeight = 0_lu) override;

    bool canDropAnonymousBlockChild() const override { return false; }

    bool isComputingTrackSizes() const { return m_isComputingTrackSizes; }

    bool hasDefiniteLogicalHeight() const;
    const std::optional<LayoutUnit> availableLogicalHeightForContentBox() const;

    void setNeedsItemPlacement(SubgridDidChange descendantSubgridsNeedItemPlacement = SubgridDidChange::No);
    const Vector<LayoutUnit>& trackSizesForComputedStyle(Style::GridTrackSizingDirection) const LIFETIME_BOUND;

    const Vector<LayoutUnit>& columnPositions() const LIFETIME_BOUND { return m_columnPositions; }
    const Vector<LayoutUnit>& rowPositions() const LIFETIME_BOUND { return m_rowPositions; }
    const Vector<LayoutUnit>& positions(Style::GridTrackSizingDirection direction) const LIFETIME_BOUND { return direction == Style::GridTrackSizingDirection::Columns ? columnPositions() : rowPositions(); }

    unsigned autoRepeatCountForDirection(Style::GridTrackSizingDirection direction) const { return currentGrid().autoRepeatTracks(direction); }
    unsigned explicitGridStartForDirection(Style::GridTrackSizingDirection direction) const { return currentGrid().explicitGridStart(direction); }

    // Required by GridTrackSizingAlgorithm. Keep them under control.
    LayoutUnit guttersSize(Style::GridTrackSizingDirection, unsigned startLine, unsigned span, std::optional<LayoutUnit> availableSize) const;
    LayoutUnit NODELETE gridItemOffset(Style::GridTrackSizingDirection) const;

    std::optional<LayoutUnit> explicitIntrinsicInnerLogicalSize(Style::GridTrackSizingDirection) const;
    void updateGridAreaLogicalSize(RenderBox&, std::optional<LayoutUnit> width, std::optional<LayoutUnit> height) const;
    bool isBaselineAlignmentForGridItem(const RenderBox&) const;
    bool isBaselineAlignmentForGridItem(const RenderBox& gridItem, Style::GridTrackSizingDirection alignmentContext) const;

    StyleContentAlignmentData contentAlignment(Style::GridTrackSizingDirection) const;
    StyleSelfAlignmentData selfAlignmentForGridItem(const RenderBox&, LogicalBoxAxis containingAxis, StretchingMode = StretchingMode::Normal, const Style::ComputedStyle* = nullptr) const;
    bool willStretchItem(const RenderBox& item, LogicalBoxAxis containingAxis, StretchingMode = StretchingMode::Normal) const override;

    // These functions handle the actual implementation of layoutBlock based on if
    // the grid is a standard grid or a grid lanes one. While grid lanes layout is an extension of grid,
    // keeping the logic in the same function was leading to a messy amount of if statements being added to handle
    // specific grid lanes cases.
    void layoutGrid(RelayoutChildren);
    void layoutGridLanes(RelayoutChildren);

    // Computes the span relative to this RenderGrid, even if the RenderBox is a grid item
    // of a descendant subgrid.
    GridSpan gridSpanForGridItem(const RenderBox&, Style::GridTrackSizingDirection) const;

    bool isSubgrid() const;
    bool isSubgrid(Style::GridTrackSizingDirection) const;
    bool isSubgridRows() const { return isSubgrid(Style::GridTrackSizingDirection::Rows); }
    bool isSubgridColumns() const { return isSubgrid(Style::GridTrackSizingDirection::Columns); }
    bool isSubgridInParentDirection(Style::GridTrackSizingDirection parentDirection) const;

    // Returns true if this grid is inheriting subgridded tracks for
    // the given direction from the specified ancestor. This handles
    // nested subgrids, where ancestor may not be our direct parent.
    bool isSubgridOf(Style::GridTrackSizingDirection, const RenderGrid& ancestor) const;

    bool NODELETE isGridLanes() const;
    bool isStackingAxis(Style::GridTrackSizingDirection) const;
    bool isStackingAxis(LogicalBoxAxis axis) const { return isStackingAxis(Style::gridTrackSizingDirection(axis)); }
    bool hasStackingAxisRows() const { return isStackingAxis(Style::GridTrackSizingDirection::Rows); }
    bool hasStackingAxisColumns() const { return isStackingAxis(Style::GridTrackSizingDirection::Columns); }

    const Grid& NODELETE currentGrid() const LIFETIME_BOUND;
    Grid& NODELETE currentGrid() LIFETIME_BOUND;

    unsigned numTracks(Style::GridTrackSizingDirection) const;

    void placeItems();

    std::optional<LayoutUnit> availableSpaceForGutters(Style::GridTrackSizingDirection) const;
    LayoutUnit gridGap(Style::GridTrackSizingDirection) const;
    LayoutUnit gridGap(Style::GridTrackSizingDirection, std::optional<LayoutUnit> availableSize) const;

    // The stacking axis content size produced by the most recent grid lanes layout. Unlike the rest of
    // the GridLanesResult this has to outlive layout, because the web inspector's grid overlay reads it
    // at paint time. Nothing in layout should use this; layout threads the result itself through as a
    // GridLanesResultRef instead.
    LayoutUnit NODELETE gridLanesContentSizeForWebInspectorOverlay() const { return m_gridLanesContentSizeForWebInspectorOverlay; }

    void updateIntrinsicLogicalHeightsForRowSizingFirstPassCacheAvailability();
    std::optional<GridItemSizeCache>& NODELETE intrinsicLogicalHeightsForRowSizingFirstPass() const LIFETIME_BOUND;

    bool shouldCheckExplicitIntrinsicInnerLogicalSize(Style::GridTrackSizingDirection) const;

    // Checks both the grid container and the grid since the grid container is sized
    // according to the rules of the formatting context it lives in while the size of the
    // grid is determined by the lines/grid areas which come from track sizing.
    bool isExtrinsicallySized() const;

private:
    friend class GridTrackSizingAlgorithm;
    friend class GridTrackSizingAlgorithmStrategy;
    friend class GridLanesLayout;
    friend class PositionedLayoutConstraints;
    friend class LayoutIntegration::GridLayout;

    inline void updateGridAreaWithEstimate(RenderBox& gridItem, const GridTrackSizingAlgorithm&) const;
    inline void updateGridAreaIncludingAlignment(RenderBox& gridItem) const;

    void computeLayoutRequirementsForItemsBeforeLayout(RenderGridLayoutState&) const;
    bool canSetColumnAxisStretchRequirementForItem(const RenderBox&) const;

    ASCIILiteral renderName() const override;
    std::pair<LayoutUnit, LayoutUnit> computeIntrinsicLogicalWidths() const override;

    bool selfAlignmentChangedToStretch(LogicalBoxAxis containingAxis, const Style::ComputedStyle& oldStyle, const Style::ComputedStyle& newStyle, const RenderBox& gridItem) const;
    bool selfAlignmentChangedFromStretch(LogicalBoxAxis containingAxis, const Style::ComputedStyle& oldStyle, const Style::ComputedStyle& newStyle, const RenderBox& gridItem) const;

    SubgridDidChange NODELETE subgridDidChange(const Style::ComputedStyle& oldStyle) const;
    bool NODELETE explicitGridDidResize(const Style::ComputedStyle&) const;
    bool namedGridLinesDefinitionDidChange(const Style::ComputedStyle&) const;
    bool implicitGridLinesDefinitionDidChange(const Style::ComputedStyle&) const;

    unsigned computeAutoRepeatTracksCount(Style::GridTrackSizingDirection, std::optional<LayoutUnit> availableSize) const;

    unsigned clampAutoRepeatTracks(Style::GridTrackSizingDirection, unsigned autoRepeatTracks) const;

    WTF::Range<size_t> NODELETE autoRepeatTracksRange(Style::GridTrackSizingDirection) const;
    std::unique_ptr<OrderedTrackIndexSet> computeEmptyTracksForAutoRepeat(Style::GridTrackSizingDirection) const;

    enum class ShouldUpdateGridAreaLogicalSize : bool { No, Yes };
    void performPreLayoutForGridItems(const GridTrackSizingAlgorithm&, const ShouldUpdateGridAreaLogicalSize) const;

    void placeItemsOnGrid(std::optional<LayoutUnit> availableLogicalWidth);
    void populateExplicitGridAndOrderIterator();
    GridArea createEmptyGridAreaAtSpecifiedPositionsOutsideGrid(const RenderBox&, Style::GridTrackSizingDirection, const GridSpan&) const;
    bool isPlacedWithinExtrinsicallySizedExplicitTracks(const RenderBox&) const;
    void placeSpecifiedMajorAxisItemsOnGrid(const Vector<RenderBox*>&);
    void placeAutoMajorAxisItemsOnGrid(const Vector<RenderBox*>&);
    typedef std::pair<unsigned, unsigned> AutoPlacementCursor;
    void placeAutoMajorAxisItemOnGrid(RenderBox&, AutoPlacementCursor&);
    Style::GridTrackSizingDirection NODELETE autoPlacementMajorAxisDirection() const;
    Style::GridTrackSizingDirection NODELETE autoPlacementMinorAxisDirection() const;

    static bool itemGridAreaIsWithinImplicitGrid(const GridArea& area, unsigned gridAxisLinesCount, Style::GridTrackSizingDirection gridAxisDirection)
    {
        auto itemSpan = area.span(gridAxisDirection);
        return itemSpan.startLine() < gridAxisLinesCount && itemSpan.endLine() < gridAxisLinesCount;
    }

    bool canPerformSimplifiedLayout() const final;
    void prepareGridItemForPositionedLayout(RenderBox&);
    bool NODELETE hasStaticPositionForGridItem(const RenderBox&, Style::GridTrackSizingDirection) const;
    void layoutOutOfFlowBox(RenderBox&, RelayoutChildren, bool fixedPositionObjectsOnly) override;

    void computeTrackSizesForDefiniteSize(Style::GridTrackSizingDirection, LayoutUnit availableSpace, RenderGridLayoutState&);
    std::pair<LayoutUnit, LayoutUnit> computeTrackSizesForIndefiniteSize(GridTrackSizingAlgorithm&, Style::GridTrackSizingDirection, RenderGridLayoutState&) const;
    LayoutUnit computeTrackBasedLogicalHeight() const;

    void repeatTracksSizingIfNeeded(LayoutUnit availableSpaceForColumns, LayoutUnit availableSpaceForRows, RenderGridLayoutState&);

    void updateGridAreaForAspectRatioItems(const Vector<RenderBox*>&, RenderGridLayoutState&, GridLanesResultRef);

    void layoutGridItems(RenderGridLayoutState&, GridLanesResultRef);
    void layoutGridLanesItems(RenderGridLayoutState&, const GridLanesResult&);

    void populateGridPositionsForDirection(const GridTrackSizingAlgorithm&, Style::GridTrackSizingDirection, GridLanesResultRef);

    LayoutRange gridAreaRangeForOutOfFlow(const RenderBox&, Style::GridTrackSizingDirection) const;
    std::pair<LayoutUnit, LayoutUnit> gridAreaPositionForInFlowGridItem(const RenderBox&, Style::GridTrackSizingDirection) const;

    GridAxisPosition columnAxisPositionForGridItem(const RenderBox&) const;
    GridAxisPosition rowAxisPositionForGridItem(const RenderBox&) const;
    LayoutUnit columnAxisOffsetForGridItem(const RenderBox&, GridLanesResultRef) const;
    LayoutUnit rowAxisOffsetForGridItem(const RenderBox&, GridLanesResultRef) const;
    ContentAlignmentData computeContentPositionAndDistributionOffset(Style::GridTrackSizingDirection, const LayoutUnit& availableFreeSpace, unsigned numberOfGridTracks) const;
    void setLogicalPositionForGridItem(RenderBox&, GridLanesResultRef) const;
    LayoutUnit logicalOffsetForGridItem(const RenderBox&, Style::GridTrackSizingDirection, GridLanesResultRef) const;

    LayoutUnit gridAreaBreadthForGridItemIncludingAlignmentOffsets(const RenderBox&, Style::GridTrackSizingDirection) const;

    void paintChildren(PaintInfo& forSelf, const LayoutPoint& paintOffset, PaintInfo& forChild, bool usePrintRect) override;
    bool hitTestChildren(const HitTestRequest&, HitTestResult&, const HitTestLocation&, const LayoutPoint& adjustedLocation, HitTestAction) override;
    LayoutOptionalOutsets allowedLayoutOverflow() const override;
    LayoutRect contentOverflowRect() const;

    void applyStretchAlignmentToGridItemIfNeeded(RenderBox&, RenderGridLayoutState&);
    void applySubgridStretchAlignmentToGridItemIfNeeded(RenderBox&);

    std::optional<LayoutUnit> firstLineBaseline() const final;
    std::optional<LayoutUnit> lastLineBaseline() const final;
    const RenderBox* baselineGridItem(ItemPosition alignment) const;

    LayoutUnit columnAxisBaselineOffsetForGridItem(const RenderBox&) const;
    LayoutUnit rowAxisBaselineOffsetForGridItem(const RenderBox&) const;

    unsigned NODELETE nonCollapsedTracks(Style::GridTrackSizingDirection) const;

    LayoutUnit translateRTLCoordinate(LayoutUnit) const;

    bool shouldResetLogicalHeightBeforeLayout() const override { return true; }

    bool aspectRatioPrefersInline(const RenderBox& gridItem, bool blockFlowIsColumnAxis);

    Vector<RenderBox*> computeAspectRatioDependentAndBaselineItems(RenderGridLayoutState&);

    GridSpan gridSpanForOutOfFlowGridItem(const RenderBox&, Style::GridTrackSizingDirection) const;

    bool computeGridPositionsForOutOfFlowGridItem(const RenderBox&, Style::GridTrackSizingDirection, int&, bool&, int&, bool&) const;

    AutoRepeatType NODELETE autoRepeatType(Style::GridTrackSizingDirection) const;

    Vector<LayoutUnit>& positions(Style::GridTrackSizingDirection direction) LIFETIME_BOUND { return direction == Style::GridTrackSizingDirection::Columns ? m_columnPositions : m_rowPositions; }

    // https://drafts.csswg.org/css-grid-2/#resolved-track-list
    // The resolved value of grid-template-columns / grid-template-rows for a grid container is its
    // used value: every track listed individually with its size serialized as a length in pixels.
    // We compute this once at the end of layout instead of on demand for each getComputedStyle query.
    Vector<LayoutUnit> computeResolvedTrackList(Style::GridTrackSizingDirection) const;
    void updateResolvedTrackListsAfterLayout();
    void setResolvedTrackSizes(Vector<LayoutUnit>&& columnSizes, Vector<LayoutUnit>&& rowSizes);

    ContentAlignmentData& offsetBetweenTracks(Style::GridTrackSizingDirection direction) LIFETIME_BOUND { return direction == Style::GridTrackSizingDirection::Columns ? m_offsetBetweenColumns : m_offsetBetweenRows; }
    const ContentAlignmentData& offsetBetweenTracks(Style::GridTrackSizingDirection direction) const LIFETIME_BOUND { return direction == Style::GridTrackSizingDirection::Columns ? m_offsetBetweenColumns : m_offsetBetweenRows; }

    bool canCreateIntrinsicLogicalHeightsForRowSizingFirstPassCache() const;

    class GridWrapper {
        Grid m_layoutGrid;
    public:
        GridWrapper(RenderGrid&);
        void NODELETE resetCurrentGrid() const;
        mutable std::reference_wrapper<Grid> m_currentGrid { std::ref(m_layoutGrid) };
    } m_grid;

    // FIXME: Refactor m_trackSizingAlgorithm to be inside of layoutGrid and layoutGridLanes.
    // https://bugs.webkit.org/show_bug.cgi?id=277496
    GridTrackSizingAlgorithm m_trackSizingAlgorithm;

    Vector<LayoutUnit> m_columnPositions;
    Vector<LayoutUnit> m_rowPositions;
    ContentAlignmentData m_offsetBetweenColumns;
    ContentAlignmentData m_offsetBetweenRows;
    LayoutUnit m_gridLanesContentSizeForWebInspectorOverlay;

    // Cached resolved value of grid-template-columns / grid-template-rows (see computeResolvedTrackList).
    // Invalidated when a full (non-simplified) layout begins and repopulated at the end of that layout,
    // so a stale read trips the assert in trackSizesForComputedStyle().
    struct ResolvedTrackList {
        Vector<LayoutUnit> columnSizes;
        Vector<LayoutUnit> rowSizes;
        bool isValid { false };

        void invalidate()
        {
            isValid = false;
            columnSizes.clear();
            rowSizes.clear();
        }

        const Vector<LayoutUnit>& sizes(Style::GridTrackSizingDirection direction) const LIFETIME_BOUND { return direction == Style::GridTrackSizingDirection::Columns ? columnSizes : rowSizes; }
        Vector<LayoutUnit>& sizes(Style::GridTrackSizingDirection direction) LIFETIME_BOUND { return direction == Style::GridTrackSizingDirection::Columns ? columnSizes : rowSizes; }
    } m_resolvedTrackList;

    mutable std::optional<GridItemSizeCache> m_intrinsicLogicalHeightsForRowSizingFirstPass;

    bool layoutUsingGridFormattingContext();

    std::optional<bool> m_hasGridFormattingContextLayout;

    mutable bool m_isComputingTrackSizes { false };
};

} // namespace WebCore

SPECIALIZE_TYPE_TRAITS_RENDER_OBJECT(RenderGrid, isRenderGrid())