Source/WebCore/rendering/RenderNamedFlowFragment.cpp

/*
 * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
 *
 * 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
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 *    disclaimer.
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 *    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 THE COPYRIGHT HOLDER "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 THE COPYRIGHT HOLDER 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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#include "config.h"
#include "RenderNamedFlowFragment.h"

#include "FlowThreadController.h"
#include "PaintInfo.h"
#include "RenderBoxRegionInfo.h"
#include "RenderFlowThread.h"
#include "RenderIterator.h"
#include "RenderNamedFlowThread.h"
#include "RenderTableCell.h"
#include "RenderView.h"
#include "StyleResolver.h"

#include <wtf/StackStats.h>

namespace WebCore {

RenderNamedFlowFragment::RenderNamedFlowFragment(Document& document, RenderStyle&& style)
    : RenderRegion(document, WTFMove(style), nullptr)
    , m_hasCustomRegionStyle(false)
    , m_hasAutoLogicalHeight(false)
    , m_hasComputedAutoHeight(false)
    , m_computedAutoHeight(0)
{
}

RenderNamedFlowFragment::~RenderNamedFlowFragment()
{
}

RenderStyle RenderNamedFlowFragment::createStyle(const RenderStyle& parentStyle)
{
    auto style = RenderStyle::createAnonymousStyleWithDisplay(parentStyle, BLOCK);

    style.setFlowThread(parentStyle.flowThread());
    style.setRegionThread(parentStyle.regionThread());
    style.setRegionFragment(parentStyle.regionFragment());

    return style;
}

void RenderNamedFlowFragment::updateRegionFlags()
{
    checkRegionStyle();
    updateRegionHasAutoLogicalHeightFlag();
}

void RenderNamedFlowFragment::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderRegion::styleDidChange(diff, oldStyle);

    if (!isValid())
        return;

    updateRegionFlags();

    if (parent() && parent()->needsLayout())
        setNeedsLayout(MarkOnlyThis);
}

void RenderNamedFlowFragment::getRanges(Vector<RefPtr<Range>>& rangeObjects) const
{
    const RenderNamedFlowThread& namedFlow = view().flowThreadController().ensureRenderFlowThreadWithName(style().regionThread());
    namedFlow.getRanges(rangeObjects, this);
}

bool RenderNamedFlowFragment::shouldHaveAutoLogicalHeight() const
{
    ASSERT(parent());

    const RenderStyle& styleToUse = parent()->style();
    bool hasSpecifiedEndpointsForHeight = styleToUse.logicalTop().isSpecified() && styleToUse.logicalBottom().isSpecified();
    bool hasAnchoredEndpointsForHeight = parent()->isOutOfFlowPositioned() && hasSpecifiedEndpointsForHeight;
    return styleToUse.logicalHeight().isAuto() && !hasAnchoredEndpointsForHeight;
}

void RenderNamedFlowFragment::incrementAutoLogicalHeightCount()
{
    ASSERT(isValid());
    ASSERT(m_hasAutoLogicalHeight);

    m_flowThread->incrementAutoLogicalHeightRegions();
}

void RenderNamedFlowFragment::decrementAutoLogicalHeightCount()
{
    ASSERT(isValid());

    m_flowThread->decrementAutoLogicalHeightRegions();
}

void RenderNamedFlowFragment::updateRegionHasAutoLogicalHeightFlag()
{
    ASSERT(isValid());

    bool didHaveAutoLogicalHeight = m_hasAutoLogicalHeight;
    m_hasAutoLogicalHeight = shouldHaveAutoLogicalHeight();
    if (didHaveAutoLogicalHeight == m_hasAutoLogicalHeight)
        return;

    if (m_hasAutoLogicalHeight)
        incrementAutoLogicalHeightCount();
    else {
        clearComputedAutoHeight();
        decrementAutoLogicalHeightCount();
    }
}

void RenderNamedFlowFragment::updateLogicalHeight()
{
    RenderRegion::updateLogicalHeight();

    if (!hasAutoLogicalHeight())
        return;

    // We want to update the logical height based on the computed auto-height
    // only after the measure cotnent layout phase when all the
    // auto logical height regions have a computed auto-height.
    if (m_flowThread->inMeasureContentLayoutPhase())
        return;

    // There may be regions with auto logical height that during the prerequisite layout phase
    // did not have the chance to layout flow thread content. Because of that, these regions do not
    // have a computedAutoHeight and they will not be able to fragment any flow
    // thread content.
    if (!hasComputedAutoHeight())
        return;

    LayoutUnit newLogicalHeight = computedAutoHeight() + borderAndPaddingLogicalHeight();
    ASSERT(newLogicalHeight < RenderFlowThread::maxLogicalHeight());
    if (newLogicalHeight > logicalHeight()) {
        setLogicalHeight(newLogicalHeight);
        // Recalculate position of the render block after new logical height is set.
        // (needed in absolute positioning case with bottom alignment for example)
        RenderRegion::updateLogicalHeight();
    }
}

LayoutUnit RenderNamedFlowFragment::pageLogicalHeight() const
{
    ASSERT(isValid());
    if (hasComputedAutoHeight() && m_flowThread->inMeasureContentLayoutPhase()) {
        ASSERT(hasAutoLogicalHeight());
        return computedAutoHeight();
    }
    return m_flowThread->isHorizontalWritingMode() ? contentHeight() : contentWidth();
}

// This method returns the maximum page size of a region with auto-height. This is the initial
// height value for auto-height regions in the first layout phase of the parent named flow.
LayoutUnit RenderNamedFlowFragment::maxPageLogicalHeight() const
{
    ASSERT(isValid());
    ASSERT(hasAutoLogicalHeight() && m_flowThread->inMeasureContentLayoutPhase());
    ASSERT(isAnonymous());
    ASSERT(parent());

    const RenderStyle& styleToUse = parent()->style();
    return styleToUse.logicalMaxHeight().isUndefined() ? RenderFlowThread::maxLogicalHeight() : downcast<RenderBlock>(*parent()).computeReplacedLogicalHeightUsing(MaxSize, styleToUse.logicalMaxHeight());
}

LayoutRect RenderNamedFlowFragment::flowThreadPortionRectForClipping(bool isFirstRegionInRange, bool isLastRegionInRange) const
{
    // Elements flowed into a region should not be painted past the region's content box
    // if they continue to flow into another region in that direction.
    // If they do not continue into another region in that direction, they should be
    // painted all the way to the region's border box.
    // Regions with overflow:hidden will apply clip at the border box, not the content box.
    
    LayoutRect clippingRect = flowThreadPortionRect();
    RenderBlockFlow& container = fragmentContainer();
    if (container.style().hasPadding()) {
        if (isFirstRegionInRange) {
            if (flowThread()->isHorizontalWritingMode()) {
                clippingRect.move(0, -container.paddingBefore());
                clippingRect.expand(0, container.paddingBefore());
            } else {
                clippingRect.move(-container.paddingBefore(), 0);
                clippingRect.expand(container.paddingBefore(), 0);
            }
        }
        
        if (isLastRegionInRange) {
            if (flowThread()->isHorizontalWritingMode())
                clippingRect.expand(0, container.paddingAfter());
            else
                clippingRect.expand(container.paddingAfter(), 0);
        }
        
        if (flowThread()->isHorizontalWritingMode()) {
            clippingRect.move(-container.paddingStart(), 0);
            clippingRect.expand(container.paddingStart() + container.paddingEnd(), 0);
        } else {
            clippingRect.move(0, -container.paddingStart());
            clippingRect.expand(0, container.paddingStart() + container.paddingEnd());
        }
    }
    
    return clippingRect;
}

RenderBlockFlow& RenderNamedFlowFragment::fragmentContainer() const
{
    ASSERT(parent());
    ASSERT(parent()->isRenderNamedFlowFragmentContainer());
    return downcast<RenderBlockFlow>(*parent());
}

RenderLayer& RenderNamedFlowFragment::fragmentContainerLayer() const
{
    ASSERT(fragmentContainer().layer());
    return *fragmentContainer().layer();
}

bool RenderNamedFlowFragment::shouldClipFlowThreadContent() const
{
    if (fragmentContainer().hasOverflowClip())
        return true;
    
    return isLastRegion() && (style().regionFragment() == BreakRegionFragment);
}
    
LayoutSize RenderNamedFlowFragment::offsetFromContainer(RenderElement& container, const LayoutPoint&, bool*) const
{
    ASSERT_UNUSED(container, &fragmentContainer() == &container);
    ASSERT_UNUSED(container, this->container() == &container);
    return topLeftLocationOffset();
}

void RenderNamedFlowFragment::layoutBlock(bool relayoutChildren, LayoutUnit)
{
    StackStats::LayoutCheckPoint layoutCheckPoint;
    RenderRegion::layoutBlock(relayoutChildren);

    if (isValid()) {
        if (m_flowThread->inOverflowLayoutPhase() || m_flowThread->inFinalLayoutPhase()) {
            computeOverflowFromFlowThread();
            updateOversetState();
        }

        if (hasAutoLogicalHeight() && m_flowThread->inMeasureContentLayoutPhase()) {
            m_flowThread->invalidateRegions();
            clearComputedAutoHeight();
            return;
        }
    }
}

void RenderNamedFlowFragment::invalidateRegionIfNeeded()
{
    if (!isValid())
        return;

    LayoutRect oldRegionRect(flowThreadPortionRect());
    if (!isHorizontalWritingMode())
        oldRegionRect = oldRegionRect.transposedRect();

    if ((oldRegionRect.width() != pageLogicalWidth() || oldRegionRect.height() != pageLogicalHeight()) && !m_flowThread->inFinalLayoutPhase()) {
        // This can happen even if we are in the inConstrainedLayoutPhase and it will trigger a pathological layout of the flow thread.
        m_flowThread->invalidateRegions();
    }
}

void RenderNamedFlowFragment::setRegionOversetState(RegionOversetState state)
{
    ASSERT(generatingElement());

    generatingElement()->setRegionOversetState(state);
}

RegionOversetState RenderNamedFlowFragment::regionOversetState() const
{
    ASSERT(generatingElement());

    if (!isValid())
        return RegionUndefined;

    return generatingElement()->regionOversetState();
}

void RenderNamedFlowFragment::updateOversetState()
{
    ASSERT(isValid());

    RenderNamedFlowThread* flowThread = namedFlowThread();
    ASSERT(flowThread && (flowThread->inOverflowLayoutPhase() || flowThread->inFinalLayoutPhase()));

    LayoutUnit flowContentBottom = flowThread->flowContentBottom();
    bool isHorizontalWritingMode = flowThread->isHorizontalWritingMode();

    LayoutUnit flowMin = flowContentBottom - (isHorizontalWritingMode ? flowThreadPortionRect().y() : flowThreadPortionRect().x());
    LayoutUnit flowMax = flowContentBottom - (isHorizontalWritingMode ? flowThreadPortionRect().maxY() : flowThreadPortionRect().maxX());

    RegionOversetState previousState = regionOversetState();
    RegionOversetState state = RegionFit;
    if (flowMin <= 0)
        state = RegionEmpty;
    if (flowMax > 0 && isLastRegion())
        state = RegionOverset;
    
    setRegionOversetState(state);

    // Determine whether the NamedFlow object should dispatch a regionOversetChange event
    if (previousState != state)
        flowThread->setDispatchRegionOversetChangeEvent(true);
}

void RenderNamedFlowFragment::checkRegionStyle()
{
    ASSERT(isValid());

    bool customRegionStyle = false;

    // FIXME: Region styling doesn't work for pseudo elements.
    if (!isPseudoElement())
        customRegionStyle = generatingElement()->styleResolver().checkRegionStyle(generatingElement());
    setHasCustomRegionStyle(customRegionStyle);
    downcast<RenderNamedFlowThread>(*m_flowThread).checkRegionsWithStyling();
}

std::unique_ptr<RenderStyle> RenderNamedFlowFragment::computeStyleInRegion(RenderElement& renderer, const RenderStyle& parentStyle) const
{
    ASSERT(!renderer.isAnonymous());

    // FIXME: Region styling fails for pseudo-elements because the renderers don't have a node.
    auto renderObjectRegionStyle = renderer.element()->styleResolver().styleForElement(*renderer.element(), &parentStyle, nullptr, MatchAllRules, this).renderStyle;

    return renderObjectRegionStyle;
}

void RenderNamedFlowFragment::computeChildrenStyleInRegion(RenderElement& renderer)
{
    for (auto& child : childrenOfType<RenderElement>(renderer)) {
        auto it = m_rendererRegionStyle.find(&child);

        std::unique_ptr<RenderStyle> childStyleInRegion;
        bool objectRegionStyleCached = false;
        if (it != m_rendererRegionStyle.end()) {
            childStyleInRegion = RenderStyle::clonePtr(*it->value.style);
            objectRegionStyleCached = true;
        } else {
            if (child.isAnonymous() || child.isInFlowRenderFlowThread())
                childStyleInRegion =  std::make_unique<RenderStyle>(RenderStyle::createAnonymousStyleWithDisplay(renderer.style(), child.style().display()));
            else
                childStyleInRegion = computeStyleInRegion(child, renderer.style());
        }

        setRendererStyleInRegion(child, WTFMove(childStyleInRegion), objectRegionStyleCached);
        computeChildrenStyleInRegion(child);
    }
}

void RenderNamedFlowFragment::setRendererStyleInRegion(RenderElement& renderer, std::unique_ptr<RenderStyle> styleInRegion, bool objectRegionStyleCached)
{
    ASSERT(renderer.flowThreadContainingBlock());

    std::unique_ptr<RenderStyle> objectOriginalStyle = RenderStyle::clonePtr(renderer.style());
    renderer.setStyleInternal(WTFMove(*styleInRegion));

    if (is<RenderBoxModelObject>(renderer) && !renderer.hasVisibleBoxDecorations()) {
        bool hasVisibleBoxDecorations = is<RenderTableCell>(renderer)
        || renderer.style().hasBackground()
        || renderer.style().hasVisibleBorder()
        || renderer.style().hasAppearance()
        || renderer.style().boxShadow();
        renderer.setHasVisibleBoxDecorations(hasVisibleBoxDecorations);
    }

    ObjectRegionStyleInfo styleInfo;
    styleInfo.style = WTFMove(objectOriginalStyle);
    styleInfo.cached = objectRegionStyleCached;
    m_rendererRegionStyle.set(&renderer, WTFMove(styleInfo));
}

void RenderNamedFlowFragment::clearObjectStyleInRegion(const RenderElement& object)
{
    m_rendererRegionStyle.remove(&object);

    // Clear the style for the children of this object.
    for (auto& child : childrenOfType<RenderElement>(object))
        clearObjectStyleInRegion(child);
}

void RenderNamedFlowFragment::setRegionObjectsRegionStyle()
{
    if (!hasCustomRegionStyle())
        return;

    // Start from content nodes and recursively compute the style in region for the render objects below.
    // If the style in region was already computed, used that style instead of computing a new one.
    const RenderNamedFlowThread& namedFlow = view().flowThreadController().ensureRenderFlowThreadWithName(style().regionThread());
    const NamedFlowContentElements& contentElements = namedFlow.contentElements();

    for (const auto& element : contentElements) {
        // The list of content nodes contains also the nodes with display:none.
        if (!element->renderer())
            continue;
        auto& renderer = *element->renderer();

        // If the content node does not flow any of its children in this region,
        // we do not compute any style for them in this region.
        if (!flowThread()->objectInFlowRegion(&renderer, this))
            continue;

        // If the object has style in region, use that instead of computing a new one.
        auto it = m_rendererRegionStyle.find(&renderer);
        std::unique_ptr<RenderStyle> objectStyleInRegion;
        bool objectRegionStyleCached = false;
        if (it != m_rendererRegionStyle.end()) {
            objectStyleInRegion = RenderStyle::clonePtr(*it->value.style);
            ASSERT(it->value.cached);
            objectRegionStyleCached = true;
        } else
            objectStyleInRegion = computeStyleInRegion(renderer, style());

        setRendererStyleInRegion(renderer, WTFMove(objectStyleInRegion), objectRegionStyleCached);

        computeChildrenStyleInRegion(renderer);
    }
}

void RenderNamedFlowFragment::restoreRegionObjectsOriginalStyle()
{
    if (!hasCustomRegionStyle())
        return;

    RendererRegionStyleMap temp;
    for (auto& objectPair : m_rendererRegionStyle) {
        auto* object = const_cast<RenderElement*>(objectPair.key);
        std::unique_ptr<RenderStyle> objectRegionStyle = RenderStyle::clonePtr(object->style());
        std::unique_ptr<RenderStyle> objectOriginalStyle = RenderStyle::clonePtr(*objectPair.value.style);

        bool shouldCacheRegionStyle = objectPair.value.cached;
        if (!shouldCacheRegionStyle) {
            // Check whether we should cache the computed style in region.
            unsigned changedContextSensitiveProperties = ContextSensitivePropertyNone;
            StyleDifference styleDiff = objectOriginalStyle->diff(*objectRegionStyle, changedContextSensitiveProperties);
            if (styleDiff < StyleDifferenceLayoutPositionedMovementOnly)
                shouldCacheRegionStyle = true;
        }
        if (shouldCacheRegionStyle) {
            ObjectRegionStyleInfo styleInfo;
            styleInfo.style = WTFMove(objectRegionStyle);
            styleInfo.cached = true;
            temp.set(object, WTFMove(styleInfo));
        }
        object->setStyleInternal(WTFMove(*objectOriginalStyle));
    }

    m_rendererRegionStyle.swap(temp);
}

RenderNamedFlowThread* RenderNamedFlowFragment::namedFlowThread() const
{
    return downcast<RenderNamedFlowThread>(flowThread());
}

LayoutRect RenderNamedFlowFragment::visualOverflowRect() const
{
    if (isValid()) {
        RenderBoxRegionInfo* boxInfo = renderBoxRegionInfo(flowThread());
        if (boxInfo && boxInfo->overflow())
            return boxInfo->overflow()->visualOverflowRect();
    }
    
    return RenderRegion::visualOverflowRect();
}

void RenderNamedFlowFragment::attachRegion()
{
    RenderRegion::attachRegion();

    if (documentBeingDestroyed() || !isValid())
        return;

    updateRegionFlags();
}

void RenderNamedFlowFragment::detachRegion()
{
    if (hasAutoLogicalHeight()) {
        ASSERT(isValid());
        m_hasAutoLogicalHeight = false;
        clearComputedAutoHeight();
        decrementAutoLogicalHeightCount();
    }
    
    RenderRegion::detachRegion();
}

void RenderNamedFlowFragment::absoluteQuadsForBoxInRegion(Vector<FloatQuad>& quads, bool* wasFixed, const RenderBox* renderer, float localTop, float localBottom)
{
    LayoutRect layoutLocalRect(0, localTop, renderer->borderBoxRectInRegion(this).width(), localBottom - localTop);
    LayoutRect fragmentRect = rectFlowPortionForBox(renderer, layoutLocalRect);

    // We want to skip the 0px height fragments for non-empty boxes that may appear in case the bottom of the box
    // overlaps the bottom of a region.
    if (localBottom != localTop && !fragmentRect.height())
        return;

    CurrentRenderRegionMaintainer regionMaintainer(*this);
    quads.append(renderer->localToAbsoluteQuad(FloatRect(fragmentRect), UseTransforms, wasFixed));
}

} // namespace WebCore