flutter_flutter/engine/core/rendering/RenderBlockFlow.cpp

/*
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#include "sky/engine/config.h"
#include "sky/engine/core/rendering/RenderBlockFlow.h"

#include "sky/engine/core/frame/FrameView.h"
#include "sky/engine/core/frame/LocalFrame.h"
#include "sky/engine/core/frame/Settings.h"
#include "sky/engine/core/rendering/BidiRun.h"
#include "sky/engine/core/rendering/HitTestLocation.h"
#include "sky/engine/core/rendering/RenderLayer.h"
#include "sky/engine/core/rendering/RenderText.h"
#include "sky/engine/core/rendering/RenderView.h"
#include "sky/engine/core/rendering/line/LineWidth.h"
#include "sky/engine/platform/text/BidiTextRun.h"

namespace blink {

RenderBlockFlow::RenderBlockFlow(ContainerNode* node)
    : RenderBlock(node)
{
}

RenderBlockFlow::~RenderBlockFlow()
{
}

RenderBlockFlow* RenderBlockFlow::createAnonymous(Document* document)
{
    RenderBlockFlow* renderer = new RenderBlockFlow(0);
    renderer->setDocumentForAnonymous(document);
    return renderer;
}

bool RenderBlockFlow::updateLogicalWidthAndColumnWidth()
{
    return RenderBlock::updateLogicalWidthAndColumnWidth();
}

void RenderBlockFlow::layoutBlock(bool relayoutChildren)
{
    ASSERT(needsLayout());
    ASSERT(isInlineBlock() || !isInline());

    if (!relayoutChildren && simplifiedLayout())
        return;

    SubtreeLayoutScope layoutScope(*this);

    layoutBlockFlow(relayoutChildren, layoutScope);

    updateLayerTransformAfterLayout();

    // Update our scroll information if we're overflow:auto/scroll/hidden now that we know if
    // we overflow or not.
    updateScrollInfoAfterLayout();

    if (m_paintInvalidationLogicalTop != m_paintInvalidationLogicalBottom)
        setShouldInvalidateOverflowForPaint(true);

    clearNeedsLayout();
}

inline void RenderBlockFlow::layoutBlockFlow(bool relayoutChildren, SubtreeLayoutScope& layoutScope)
{
    LayoutUnit oldLeft = logicalLeft();
    bool logicalWidthChanged = updateLogicalWidthAndColumnWidth();
    relayoutChildren |= logicalWidthChanged;

    LayoutState state(*this, locationOffset(), logicalWidthChanged);

    LayoutUnit beforeEdge = borderBefore() + paddingBefore();
    LayoutUnit afterEdge = borderAfter() + paddingAfter();
    LayoutUnit previousHeight = logicalHeight();
    setLogicalHeight(beforeEdge);

    m_paintInvalidationLogicalTop = 0;
    m_paintInvalidationLogicalBottom = 0;

    layoutChildren(relayoutChildren, layoutScope, m_paintInvalidationLogicalTop, m_paintInvalidationLogicalBottom, beforeEdge, afterEdge);

    LayoutUnit oldClientAfterEdge = clientLogicalBottom();

    updateLogicalHeight();

    if (previousHeight != logicalHeight())
        relayoutChildren = true;

    layoutPositionedObjects(relayoutChildren || isDocumentElement(), oldLeft != logicalLeft() ? ForcedLayoutAfterContainingBlockMoved : DefaultLayout);

    // Add overflow from children (unless we're multi-column, since in that case all our child overflow is clipped anyway).
    computeOverflow(oldClientAfterEdge);
}

void RenderBlockFlow::determineLogicalLeftPositionForChild(RenderBox* child)
{
    LayoutUnit startPosition = borderStart() + paddingStart();
    LayoutUnit totalAvailableLogicalWidth = borderAndPaddingLogicalWidth() + availableLogicalWidth();

    LayoutUnit childMarginStart = marginStartForChild(child);
    LayoutUnit newPosition = startPosition + childMarginStart;

    // If the child has an offset from the content edge to avoid floats then use that, otherwise let any negative
    // margin pull it back over the content edge or any positive margin push it out.
    if (child->style()->marginStartUsing(style()).isAuto())
        newPosition = std::max(newPosition, childMarginStart);

    child->setX(style()->isLeftToRightDirection() ? newPosition : totalAvailableLogicalWidth - newPosition - logicalWidthForChild(child));
}

void RenderBlockFlow::layoutBlockChild(RenderBox* child)
{
    child->computeAndSetBlockDirectionMargins(this);
    LayoutUnit marginBefore = marginBeforeForChild(child);
    child->setY(logicalHeight() + marginBefore);
    child->layoutIfNeeded();
    determineLogicalLeftPositionForChild(child);
    setLogicalHeight(logicalHeight() + marginBefore + logicalHeightForChild(child) + marginAfterForChild(child));
}

void RenderBlockFlow::layoutChildren(bool relayoutChildren, SubtreeLayoutScope& layoutScope, LayoutUnit& paintInvalidationLogicalTop, LayoutUnit& paintInvalidationLogicalBottom, LayoutUnit beforeEdge, LayoutUnit afterEdge)
{
    dirtyForLayoutFromPercentageHeightDescendants(layoutScope);

    RenderBox* next = firstChildBox();
    RenderBox* lastNormalFlowChild = 0;

    while (next) {
        RenderBox* child = next;
        next = child->nextSiblingBox();

        // FIXME: this should only be set from clearNeedsLayout crbug.com/361250
        child->setLayoutDidGetCalled(true);

        updateBlockChildDirtyBitsBeforeLayout(relayoutChildren, child);

        if (child->isOutOfFlowPositioned()) {
            child->containingBlock()->insertPositionedObject(child);
            adjustPositionedBlock(child);
            continue;
        }

        // Lay out the child.
        layoutBlockChild(child);
        lastNormalFlowChild = child;
    }

    // Negative margins can cause our height to shrink below our minimal height (border/padding).
    // If this happens, ensure that the computed height is increased to the minimal height.
    setLogicalHeight(std::max(logicalHeight() + afterEdge, beforeEdge + afterEdge));
}

void RenderBlockFlow::adjustPositionedBlock(RenderBox* child)
{
    bool hasStaticBlockPosition = child->style()->hasStaticBlockPosition();

    LayoutUnit logicalTop = logicalHeight();
    updateStaticInlinePositionForChild(child);

    RenderLayer* childLayer = child->layer();
    if (childLayer->staticBlockPosition() != logicalTop) {
        childLayer->setStaticBlockPosition(logicalTop);
        if (hasStaticBlockPosition)
            child->setChildNeedsLayout(MarkOnlyThis);
    }
}

RootInlineBox* RenderBlockFlow::createAndAppendRootInlineBox()
{
    RootInlineBox* rootBox = createRootInlineBox();
    m_lineBoxes.appendLineBox(rootBox);

    return rootBox;
}

void RenderBlockFlow::deleteLineBoxTree()
{
    m_lineBoxes.deleteLineBoxTree();
}

void RenderBlockFlow::updateStaticInlinePositionForChild(RenderBox* child)
{
    if (child->style()->isOriginalDisplayInlineType())
        setStaticInlinePositionForChild(child, startAlignedOffsetForLine(false));
    else
        setStaticInlinePositionForChild(child, startOffsetForContent());
}

void RenderBlockFlow::setStaticInlinePositionForChild(RenderBox* child, LayoutUnit inlinePosition)
{
    child->layer()->setStaticInlinePosition(inlinePosition);
}

void RenderBlockFlow::addChild(RenderObject* newChild, RenderObject* beforeChild)
{
    RenderBlock::addChild(newChild, beforeChild);
}

void RenderBlockFlow::invalidatePaintForOverflow()
{
    // FIXME: We could tighten up the left and right invalidation points if we let RenderParagraph::layoutChildren fill them in based off the particular lines
    // it had to lay out. We wouldn't need the hasOverflowClip() hack in that case either.
    LayoutUnit paintInvalidationLogicalLeft = logicalLeftVisualOverflow();
    LayoutUnit paintInvalidationLogicalRight = logicalRightVisualOverflow();
    if (hasOverflowClip()) {
        // If we have clipped overflow, we should use layout overflow as well, since visual overflow from lines didn't propagate to our block's overflow.
        // Note the old code did this as well but even for overflow:visible. The addition of hasOverflowClip() at least tightens up the hack a bit.
        // RenderParagraph::layoutChildren should be patched to compute the entire paint invalidation rect.
        paintInvalidationLogicalLeft = std::min(paintInvalidationLogicalLeft, logicalLeftLayoutOverflow());
        paintInvalidationLogicalRight = std::max(paintInvalidationLogicalRight, logicalRightLayoutOverflow());
    }

    LayoutRect paintInvalidationRect = LayoutRect(paintInvalidationLogicalLeft, m_paintInvalidationLogicalTop, paintInvalidationLogicalRight - paintInvalidationLogicalLeft, m_paintInvalidationLogicalBottom - m_paintInvalidationLogicalTop);

    if (hasOverflowClip()) {
        // Adjust the paint invalidation rect for scroll offset
        paintInvalidationRect.move(-scrolledContentOffset());

        // Don't allow this rect to spill out of our overflow box.
        paintInvalidationRect.intersect(LayoutRect(LayoutPoint(), size()));
    }

    // Make sure the rect is still non-empty after intersecting for overflow above
    if (!paintInvalidationRect.isEmpty()) {
        // Hits in media/event-attributes.html
        DisableCompositingQueryAsserts disabler;

        invalidatePaintRectangle(paintInvalidationRect); // We need to do a partial paint invalidation of our content.
    }

    m_paintInvalidationLogicalTop = 0;
    m_paintInvalidationLogicalBottom = 0;
}

GapRects RenderBlockFlow::inlineSelectionGaps(RenderBlock* rootBlock, const LayoutPoint& rootBlockPhysicalPosition, const LayoutSize& offsetFromRootBlock,
    LayoutUnit& lastLogicalTop, LayoutUnit& lastLogicalLeft, LayoutUnit& lastLogicalRight, const PaintInfo* paintInfo)
{
    GapRects result;

    bool containsStart = selectionState() == SelectionStart || selectionState() == SelectionBoth;

    if (!firstLineBox()) {
        if (containsStart) {
            // Go ahead and update our lastLogicalTop to be the bottom of the block.  <hr>s or empty blocks with height can trip this
            // case.
            lastLogicalTop = rootBlock->blockDirectionOffset(offsetFromRootBlock) + logicalHeight();
            lastLogicalLeft = logicalLeftSelectionOffset(rootBlock, logicalHeight());
            lastLogicalRight = logicalRightSelectionOffset(rootBlock, logicalHeight());
        }
        return result;
    }

    RootInlineBox* lastSelectedLine = 0;
    RootInlineBox* curr;
    for (curr = firstRootBox(); curr && !curr->hasSelectedChildren(); curr = curr->nextRootBox()) { }

    // Now paint the gaps for the lines.
    for (; curr && curr->hasSelectedChildren(); curr = curr->nextRootBox()) {
        LayoutUnit selTop =  curr->selectionTopAdjustedForPrecedingBlock();
        LayoutUnit selHeight = curr->selectionHeightAdjustedForPrecedingBlock();

        if (!containsStart && !lastSelectedLine && selectionState() != SelectionStart && selectionState() != SelectionBoth) {
            result.uniteCenter(blockSelectionGap(rootBlock, rootBlockPhysicalPosition, offsetFromRootBlock, lastLogicalTop,
                lastLogicalLeft, lastLogicalRight, selTop, paintInfo));
        }

        LayoutRect logicalRect(curr->logicalLeft(), selTop, curr->logicalWidth(), selTop + selHeight);
        logicalRect.move(offsetFromRootBlock);
        LayoutRect physicalRect = rootBlock->logicalRectToPhysicalRect(rootBlockPhysicalPosition, logicalRect);
        if (!paintInfo || (physicalRect.y() < paintInfo->rect.maxY() && physicalRect.maxY() > paintInfo->rect.y()))
            result.unite(curr->lineSelectionGap(rootBlock, rootBlockPhysicalPosition, offsetFromRootBlock, selTop, selHeight, paintInfo));

        lastSelectedLine = curr;
    }

    if (containsStart && !lastSelectedLine) {
        // VisibleSelection must start just after our last line.
        lastSelectedLine = lastRootBox();
    }

    if (lastSelectedLine && selectionState() != SelectionEnd && selectionState() != SelectionBoth) {
        // Go ahead and update our lastY to be the bottom of the last selected line.
        lastLogicalTop = rootBlock->blockDirectionOffset(offsetFromRootBlock) + lastSelectedLine->selectionBottom();
        lastLogicalLeft = logicalLeftSelectionOffset(rootBlock, lastSelectedLine->selectionBottom());
        lastLogicalRight = logicalRightSelectionOffset(rootBlock, lastSelectedLine->selectionBottom());
    }
    return result;
}

LayoutUnit RenderBlockFlow::logicalLeftSelectionOffset(RenderBlock* rootBlock, LayoutUnit position)
{
    LayoutUnit logicalLeft = logicalLeftOffsetForLine(false);
    if (logicalLeft == logicalLeftOffsetForContent())
        return RenderBlock::logicalLeftSelectionOffset(rootBlock, position);

    RenderBlock* cb = this;
    while (cb != rootBlock) {
        logicalLeft += cb->logicalLeft();
        cb = cb->containingBlock();
    }
    return logicalLeft;
}

LayoutUnit RenderBlockFlow::logicalRightSelectionOffset(RenderBlock* rootBlock, LayoutUnit position)
{
    LayoutUnit logicalRight = logicalRightOffsetForLine(false);
    if (logicalRight == logicalRightOffsetForContent())
        return RenderBlock::logicalRightSelectionOffset(rootBlock, position);

    RenderBlock* cb = this;
    while (cb != rootBlock) {
        logicalRight += cb->logicalLeft();
        cb = cb->containingBlock();
    }
    return logicalRight;
}

RootInlineBox* RenderBlockFlow::createRootInlineBox()
{
    return new RootInlineBox(*this);
}

static void updateLogicalWidthForLeftAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
    // The direction of the block should determine what happens with wide lines.
    // In particular with RTL blocks, wide lines should still spill out to the left.
    if (isLeftToRightDirection) {
        if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun)
            trailingSpaceRun->m_box->setLogicalWidth(std::max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
        return;
    }

    if (trailingSpaceRun)
        trailingSpaceRun->m_box->setLogicalWidth(0);
    else if (totalLogicalWidth > availableLogicalWidth)
        logicalLeft -= (totalLogicalWidth - availableLogicalWidth);
}

static void updateLogicalWidthForRightAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
    // Wide lines spill out of the block based off direction.
    // So even if text-align is right, if direction is LTR, wide lines should overflow out of the right
    // side of the block.
    if (isLeftToRightDirection) {
        if (trailingSpaceRun) {
            totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
            trailingSpaceRun->m_box->setLogicalWidth(0);
        }
        if (totalLogicalWidth < availableLogicalWidth)
            logicalLeft += availableLogicalWidth - totalLogicalWidth;
        return;
    }

    if (totalLogicalWidth > availableLogicalWidth && trailingSpaceRun) {
        trailingSpaceRun->m_box->setLogicalWidth(std::max<float>(0, trailingSpaceRun->m_box->logicalWidth() - totalLogicalWidth + availableLogicalWidth));
        totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
    } else
        logicalLeft += availableLogicalWidth - totalLogicalWidth;
}

static void updateLogicalWidthForCenterAlignedBlock(bool isLeftToRightDirection, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float availableLogicalWidth)
{
    float trailingSpaceWidth = 0;
    if (trailingSpaceRun) {
        totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
        trailingSpaceWidth = std::min(trailingSpaceRun->m_box->logicalWidth(), (availableLogicalWidth - totalLogicalWidth + 1) / 2);
        trailingSpaceRun->m_box->setLogicalWidth(std::max<float>(0, trailingSpaceWidth));
    }
    if (isLeftToRightDirection)
        logicalLeft += std::max<float>((availableLogicalWidth - totalLogicalWidth) / 2, 0);
    else
        logicalLeft += totalLogicalWidth > availableLogicalWidth ? (availableLogicalWidth - totalLogicalWidth) : (availableLogicalWidth - totalLogicalWidth) / 2 - trailingSpaceWidth;
}

void RenderBlockFlow::updateLogicalWidthForAlignment(const ETextAlign& textAlign, const RootInlineBox* rootInlineBox, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, unsigned expansionOpportunityCount)
{
    TextDirection direction;
    if (rootInlineBox && rootInlineBox->renderer().style()->unicodeBidi() == Plaintext)
        direction = rootInlineBox->direction();
    else
        direction = style()->direction();

    // Armed with the total width of the line (without justification),
    // we now examine our text-align property in order to determine where to position the
    // objects horizontally. The total width of the line can be increased if we end up
    // justifying text.
    switch (textAlign) {
    case LEFT:
        updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        break;
    case RIGHT:
        updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        break;
    case CENTER:
        updateLogicalWidthForCenterAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        break;
    case JUSTIFY:
        adjustInlineDirectionLineBounds(expansionOpportunityCount, logicalLeft, availableLogicalWidth);
        if (expansionOpportunityCount) {
            if (trailingSpaceRun) {
                totalLogicalWidth -= trailingSpaceRun->m_box->logicalWidth();
                trailingSpaceRun->m_box->setLogicalWidth(0);
            }
            break;
        }
        // Fall through
    case TASTART:
        if (direction == LTR)
            updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        else
            updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        break;
    case TAEND:
        if (direction == LTR)
            updateLogicalWidthForRightAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        else
            updateLogicalWidthForLeftAlignedBlock(style()->isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
        break;
    }
}

LayoutUnit RenderBlockFlow::startAlignedOffsetForLine(bool firstLine)
{
    ETextAlign textAlign = style()->textAlign();

    if (textAlign == TASTART) // FIXME: Handle TAEND here
        return startOffsetForLine(firstLine);

    // updateLogicalWidthForAlignment() handles the direction of the block so no need to consider it here
    float totalLogicalWidth = 0;
    float logicalLeft = logicalLeftOffsetForLine(false).toFloat();
    float availableLogicalWidth = logicalRightOffsetForLine(false) - logicalLeft;
    updateLogicalWidthForAlignment(textAlign, 0, 0, logicalLeft, totalLogicalWidth, availableLogicalWidth, 0);

    if (!style()->isLeftToRightDirection())
        return logicalWidth() - logicalLeft;
    return logicalLeft;
}

} // namespace blink