flutter_flutter/sky/engine/core/rendering/RenderFlexibleBox.h

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 * modification, are permitted provided that the following conditions are
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#ifndef SKY_ENGINE_CORE_RENDERING_RENDERFLEXIBLEBOX_H_
#define SKY_ENGINE_CORE_RENDERING_RENDERFLEXIBLEBOX_H_

#include "flutter/sky/engine/core/rendering/OrderIterator.h"
#include "flutter/sky/engine/core/rendering/RenderBlock.h"

namespace blink {

class RenderFlexibleBox : public RenderBlock {
public:
    RenderFlexibleBox();
    virtual ~RenderFlexibleBox();

    virtual const char* renderName() const override;

    virtual bool isFlexibleBox() const override final { return true; }
    void layout();

    virtual int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const override;
    virtual int firstLineBoxBaseline(FontBaselineOrAuto baselineType) const override;
    virtual int inlineBlockBaseline(LineDirectionMode) const override;

    virtual void paintChildren(PaintInfo&, const LayoutPoint&, Vector<RenderBox*>& layers) override final;

    bool isHorizontalFlow() const;

protected:
    virtual void computeIntrinsicLogicalWidths(LayoutUnit& minLogicalWidth, LayoutUnit& maxLogicalWidth) const override;

    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) override;
    virtual void removeChild(RenderObject*) override;

private:
    enum FlexSign {
        PositiveFlexibility,
        NegativeFlexibility,
    };

    enum PositionedLayoutMode {
        FlipForRowReverse,
        NoFlipForRowReverse,
    };

    typedef HashMap<const RenderBox*, LayoutUnit> InflexibleFlexItemSize;
    typedef Vector<RenderBox*> OrderedFlexItemList;

    struct LineContext;
    struct Violation;

    // Use an inline capacity of 8, since flexbox containers usually have less than 8 children.
    typedef Vector<LayoutRect, 8> ChildFrameRects;

    bool hasOrthogonalFlow(RenderBox* child) const;
    bool isColumnFlow() const;
    bool isLeftToRightFlow() const;
    bool isMultiline() const;
    Length flexBasisForChild(RenderBox* child) const;
    LayoutUnit crossAxisExtentForChild(RenderBox* child) const;
    LayoutUnit crossAxisIntrinsicExtentForChild(RenderBox* child) const;
    LayoutUnit childIntrinsicHeight(RenderBox* child) const;
    LayoutUnit childIntrinsicWidth(RenderBox* child) const;
    LayoutUnit mainAxisExtentForChild(RenderBox* child) const;
    LayoutUnit crossAxisExtent() const;
    LayoutUnit mainAxisExtent() const;
    LayoutUnit crossAxisContentExtent() const;
    LayoutUnit mainAxisContentExtent(LayoutUnit contentLogicalHeight);
    LayoutUnit computeMainAxisExtentForChild(RenderBox* child, SizeType, const Length& size);
    LayoutUnit flowAwareBorderStart() const;
    LayoutUnit flowAwareBorderEnd() const;
    LayoutUnit flowAwareBorderBefore() const;
    LayoutUnit flowAwareBorderAfter() const;
    LayoutUnit flowAwarePaddingStart() const;
    LayoutUnit flowAwarePaddingEnd() const;
    LayoutUnit flowAwarePaddingBefore() const;
    LayoutUnit flowAwarePaddingAfter() const;
    LayoutUnit flowAwareMarginStartForChild(RenderBox* child) const;
    LayoutUnit flowAwareMarginEndForChild(RenderBox* child) const;
    LayoutUnit flowAwareMarginBeforeForChild(RenderBox* child) const;
    LayoutUnit crossAxisMarginExtentForChild(RenderBox* child) const;
    LayoutPoint flowAwareLocationForChild(RenderBox* child) const;
    // FIXME: Supporting layout deltas.
    void setFlowAwareLocationForChild(RenderBox* child, const LayoutPoint&);
    void adjustAlignmentForChild(RenderBox* child, LayoutUnit);
    ItemPosition alignmentForChild(RenderBox* child) const;
    LayoutUnit mainAxisBorderAndPaddingExtentForChild(RenderBox* child) const;
    LayoutUnit preferredMainAxisContentExtentForChild(RenderBox* child, bool hasInfiniteLineLength, bool relayoutChildren = false);
    bool childPreferredMainAxisContentExtentRequiresLayout(RenderBox* child, bool hasInfiniteLineLength) const;
    bool needToStretchChildLogicalHeight(RenderBox* child) const;

    void layoutFlexItems(bool relayoutChildren);
    LayoutUnit autoMarginOffsetInMainAxis(const OrderedFlexItemList&, LayoutUnit& availableFreeSpace);
    void updateAutoMarginsInMainAxis(RenderBox* child, LayoutUnit autoMarginOffset);
    bool hasAutoMarginsInCrossAxis(RenderBox* child) const;
    bool updateAutoMarginsInCrossAxis(RenderBox* child, LayoutUnit availableAlignmentSpace);
    void repositionLogicalHeightDependentFlexItems(Vector<LineContext>&);
    LayoutUnit clientLogicalBottomAfterRepositioning();
    void appendChildFrameRects(ChildFrameRects&);

    LayoutUnit availableAlignmentSpaceForChild(LayoutUnit lineCrossAxisExtent, RenderBox*);
    LayoutUnit availableAlignmentSpaceForChildBeforeStretching(LayoutUnit lineCrossAxisExtent, RenderBox*);
    LayoutUnit marginBoxAscentForChild(RenderBox*);

    LayoutUnit computeChildMarginValue(Length margin);
    void prepareOrderIteratorAndMargins();
    LayoutUnit adjustChildSizeForMinAndMax(RenderBox*, LayoutUnit childSize);
    // The hypothetical main size of an item is the flex base size clamped according to its min and max main size properties
    bool computeNextFlexLine(OrderedFlexItemList& orderedChildren, LayoutUnit& sumFlexBaseSize, double& totalFlexGrow, double& totalWeightedFlexShrink, LayoutUnit& sumHypotheticalMainSize, bool& hasInfiniteLineLength, bool relayoutChildren);

    bool resolveFlexibleLengths(FlexSign, const OrderedFlexItemList&, LayoutUnit& availableFreeSpace, double& totalFlexGrow, double& totalWeightedFlexShrink, InflexibleFlexItemSize&, Vector<LayoutUnit, 16>& childSizes, bool hasInfiniteLineLength);
    void freezeViolations(const Vector<Violation>&, LayoutUnit& availableFreeSpace, double& totalFlexGrow, double& totalWeightedFlexShrink, InflexibleFlexItemSize&, bool hasInfiniteLineLength);

    void resetAutoMarginsAndLogicalTopInCrossAxis(RenderBox*);
    void setLogicalOverrideSize(RenderBox* child, LayoutUnit childPreferredSize);
    size_t numberOfInFlowPositionedChildren(const OrderedFlexItemList&) const;
    void layoutAndPlaceChildren(LayoutUnit& crossAxisOffset, const OrderedFlexItemList&, const Vector<LayoutUnit, 16>& childSizes, LayoutUnit availableFreeSpace, bool relayoutChildren, Vector<LineContext>&, bool hasInfiniteLineLength);
    void layoutColumnReverse(const OrderedFlexItemList&, LayoutUnit crossAxisOffset, LayoutUnit availableFreeSpace);
    void alignFlexLines(Vector<LineContext>&);
    void alignChildren(const Vector<LineContext>&);
    void applyStretchAlignmentToChild(RenderBox*, LayoutUnit lineCrossAxisExtent);
    void flipForRightToLeftColumn();
    void flipForWrapReverse(const Vector<LineContext>&, LayoutUnit crossAxisStartEdge);

    // This is used to cache the preferred size for orthogonal flow children so we don't have to relayout to get it
    HashMap<const RenderObject*, LayoutUnit> m_intrinsicSizeAlongMainAxis;

    mutable OrderIterator m_orderIterator;
    int m_numberOfInFlowChildrenOnFirstLine;
};

DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderFlexibleBox, isFlexibleBox());

} // namespace blink

#endif  // SKY_ENGINE_CORE_RENDERING_RENDERFLEXIBLEBOX_H_