Source/WebCore/rendering/RenderNamedFlowFragment.cpp - WebKit - Git at Google

 /*
  * 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
  *    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 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
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */

 #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 "RenderView.h"
 #include "StyleResolver.h"

 #include <wtf/StackStats.h>

 namespace WebCore {

 RenderNamedFlowFragment::RenderNamedFlowFragment(Document& document, PassRef<RenderStyle> style)
     : RenderRegion(document, WTF::move(style), nullptr)
     , m_hasCustomRegionStyle(false)
     , m_hasAutoLogicalHeight(false)
     , m_hasComputedAutoHeight(false)
     , m_computedAutoHeight(0)
 {
 }

 RenderNamedFlowFragment::~RenderNamedFlowFragment()
 {
 }

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

     style.get().setFlowThread(parentStyle.flowThread());
     style.get().setRegionThread(parentStyle.regionThread());
     style.get().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(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 *toRenderBlockFlow(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(RenderObject* o, const LayoutPoint&, bool*) const
 {
     ASSERT(&fragmentContainer() == o);
     ASSERT(container() == o);
     UNUSED_PARAM(o);
     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 = view().document().ensureStyleResolver().checkRegionStyle(generatingElement());
     setHasCustomRegionStyle(customRegionStyle);
     toRenderNamedFlowThread(m_flowThread)->checkRegionsWithStyling();
 }

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

     // FIXME: Region styling fails for pseudo-elements because the renderers don't have a node.
     RefPtr<RenderStyle> renderObjectRegionStyle = renderer.view().document().ensureStyleResolver().styleForElement(renderer.element(), &parentStyle, DisallowStyleSharing, MatchAllRules, this);

     return renderObjectRegionStyle.release();
 }

 void RenderNamedFlowFragment::computeChildrenStyleInRegion(RenderElement& renderer)
 {
     for (auto& child : childrenOfType<RenderObject>(renderer)) {

         auto it = m_renderObjectRegionStyle.find(&child);

         RefPtr<RenderStyle> childStyleInRegion;
         bool objectRegionStyleCached = false;
         if (it != m_renderObjectRegionStyle.end()) {
             childStyleInRegion = it->value.style;
             objectRegionStyleCached = true;
         } else {
             if (child.isAnonymous() || child.isInFlowRenderFlowThread())
                 childStyleInRegion = RenderStyle::createAnonymousStyleWithDisplay(&renderer.style(), child.style().display());
             else if (child.isText())
                 childStyleInRegion = RenderStyle::clone(&renderer.style());
             else
                 childStyleInRegion = computeStyleInRegion(toRenderElement(child), renderer.style());
         }

         setObjectStyleInRegion(&child, childStyleInRegion, objectRegionStyleCached);

         if (child.isRenderElement())
             computeChildrenStyleInRegion(toRenderElement(child));
     }
 }

 void RenderNamedFlowFragment::setObjectStyleInRegion(RenderObject* object, PassRefPtr<RenderStyle> styleInRegion, bool objectRegionStyleCached)
 {
     ASSERT(object->flowThreadContainingBlock());

     RefPtr<RenderStyle> objectOriginalStyle = &object->style();
     if (object->isRenderElement())
         toRenderElement(object)->setStyleInternal(*styleInRegion);

     if (object->isBoxModelObject() && !object->hasBoxDecorations()) {
         bool hasBoxDecorations = object->isTableCell()
         || object->style().hasBackground()
         || object->style().hasBorder()
         || object->style().hasAppearance()
         || object->style().boxShadow();
         object->setHasBoxDecorations(hasBoxDecorations);
     }

     ObjectRegionStyleInfo styleInfo;
     styleInfo.style = objectOriginalStyle;
     styleInfo.cached = objectRegionStyleCached;
     m_renderObjectRegionStyle.set(object, styleInfo);
 }

 void RenderNamedFlowFragment::clearObjectStyleInRegion(const RenderObject* object)
 {
     ASSERT(object);
     m_renderObjectRegionStyle.remove(object);

     // Clear the style for the children of this object.
     for (RenderObject* child = object->firstChildSlow(); child; child = child->nextSibling())
         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;

         RenderElement* object = 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(object, this))
             continue;

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

         setObjectStyleInRegion(object, objectStyleInRegion, objectRegionStyleCached);

         computeChildrenStyleInRegion(*object);
     }
 }

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

     RenderObjectRegionStyleMap temp;
     for (auto& objectPair : m_renderObjectRegionStyle) {
         RenderObject* object = const_cast<RenderObject*>(objectPair.key);
         RefPtr<RenderStyle> objectRegionStyle = &object->style();
         RefPtr<RenderStyle> objectOriginalStyle = objectPair.value.style;
         if (object->isRenderElement())
             toRenderElement(object)->setStyleInternal(*objectOriginalStyle);

         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.get(), changedContextSensitiveProperties);
             if (styleDiff < StyleDifferenceLayoutPositionedMovementOnly)
                 shouldCacheRegionStyle = true;
         }
         if (shouldCacheRegionStyle) {
             ObjectRegionStyleInfo styleInfo;
             styleInfo.style = objectRegionStyle;
             styleInfo.cached = true;
             temp.set(object, styleInfo);
         }
     }

     m_renderObjectRegionStyle.swap(temp);
 }

 RenderNamedFlowThread* RenderNamedFlowFragment::namedFlowThread() const
 {
     return toRenderNamedFlowThread(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), 0 /* mode */, wasFixed));
 }

 } // namespace WebCore
	/*
	* 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
	* 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 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
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
	* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
	* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*/

	#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 "RenderView.h"
	#include "StyleResolver.h"

	#include <wtf/StackStats.h>

	namespace WebCore {

	RenderNamedFlowFragment::RenderNamedFlowFragment(Document& document, PassRef<RenderStyle> style)
	: RenderRegion(document, WTF::move(style), nullptr)
	, m_hasCustomRegionStyle(false)
	, m_hasAutoLogicalHeight(false)
	, m_hasComputedAutoHeight(false)
	, m_computedAutoHeight(0)
	{
	}

	RenderNamedFlowFragment::~RenderNamedFlowFragment()
	{
	}

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

	style.get().setFlowThread(parentStyle.flowThread());
	style.get().setRegionThread(parentStyle.regionThread());
	style.get().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(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 *toRenderBlockFlow(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(RenderObject* o, const LayoutPoint&, bool*) const
	{
	ASSERT(&fragmentContainer() == o);
	ASSERT(container() == o);
	UNUSED_PARAM(o);
	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 = view().document().ensureStyleResolver().checkRegionStyle(generatingElement());
	setHasCustomRegionStyle(customRegionStyle);
	toRenderNamedFlowThread(m_flowThread)->checkRegionsWithStyling();
	}

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

	// FIXME: Region styling fails for pseudo-elements because the renderers don't have a node.
	RefPtr<RenderStyle> renderObjectRegionStyle = renderer.view().document().ensureStyleResolver().styleForElement(renderer.element(), &parentStyle, DisallowStyleSharing, MatchAllRules, this);

	return renderObjectRegionStyle.release();
	}

	void RenderNamedFlowFragment::computeChildrenStyleInRegion(RenderElement& renderer)
	{
	for (auto& child : childrenOfType<RenderObject>(renderer)) {

	auto it = m_renderObjectRegionStyle.find(&child);

	RefPtr<RenderStyle> childStyleInRegion;
	bool objectRegionStyleCached = false;
	if (it != m_renderObjectRegionStyle.end()) {
	childStyleInRegion = it->value.style;
	objectRegionStyleCached = true;
	} else {
	if (child.isAnonymous() \|\| child.isInFlowRenderFlowThread())
	childStyleInRegion = RenderStyle::createAnonymousStyleWithDisplay(&renderer.style(), child.style().display());
	else if (child.isText())
	childStyleInRegion = RenderStyle::clone(&renderer.style());
	else
	childStyleInRegion = computeStyleInRegion(toRenderElement(child), renderer.style());
	}

	setObjectStyleInRegion(&child, childStyleInRegion, objectRegionStyleCached);

	if (child.isRenderElement())
	computeChildrenStyleInRegion(toRenderElement(child));
	}
	}

	void RenderNamedFlowFragment::setObjectStyleInRegion(RenderObject* object, PassRefPtr<RenderStyle> styleInRegion, bool objectRegionStyleCached)
	{
	ASSERT(object->flowThreadContainingBlock());

	RefPtr<RenderStyle> objectOriginalStyle = &object->style();
	if (object->isRenderElement())
	toRenderElement(object)->setStyleInternal(*styleInRegion);

	if (object->isBoxModelObject() && !object->hasBoxDecorations()) {
	bool hasBoxDecorations = object->isTableCell()
	\|\| object->style().hasBackground()
	\|\| object->style().hasBorder()
	\|\| object->style().hasAppearance()
	\|\| object->style().boxShadow();
	object->setHasBoxDecorations(hasBoxDecorations);
	}

	ObjectRegionStyleInfo styleInfo;
	styleInfo.style = objectOriginalStyle;
	styleInfo.cached = objectRegionStyleCached;
	m_renderObjectRegionStyle.set(object, styleInfo);
	}

	void RenderNamedFlowFragment::clearObjectStyleInRegion(const RenderObject* object)
	{
	ASSERT(object);
	m_renderObjectRegionStyle.remove(object);

	// Clear the style for the children of this object.
	for (RenderObject* child = object->firstChildSlow(); child; child = child->nextSibling())
	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;

	RenderElement* object = 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(object, this))
	continue;

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

	setObjectStyleInRegion(object, objectStyleInRegion, objectRegionStyleCached);

	computeChildrenStyleInRegion(*object);
	}
	}

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

	RenderObjectRegionStyleMap temp;
	for (auto& objectPair : m_renderObjectRegionStyle) {
	RenderObject* object = const_cast<RenderObject*>(objectPair.key);
	RefPtr<RenderStyle> objectRegionStyle = &object->style();
	RefPtr<RenderStyle> objectOriginalStyle = objectPair.value.style;
	if (object->isRenderElement())
	toRenderElement(object)->setStyleInternal(*objectOriginalStyle);

	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.get(), changedContextSensitiveProperties);
	if (styleDiff < StyleDifferenceLayoutPositionedMovementOnly)
	shouldCacheRegionStyle = true;
	}
	if (shouldCacheRegionStyle) {
	ObjectRegionStyleInfo styleInfo;
	styleInfo.style = objectRegionStyle;
	styleInfo.cached = true;
	temp.set(object, styleInfo);
	}
	}

	m_renderObjectRegionStyle.swap(temp);
	}

	RenderNamedFlowThread* RenderNamedFlowFragment::namedFlowThread() const
	{
	return toRenderNamedFlowThread(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), 0 /* mode */, wasFixed));
	}

	} // namespace WebCore