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RenderTreeBuilder.cpp
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RenderTreeBuilder.cpp
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/*
* Copyright (C) 2017 Apple Inc. 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 APPLE INC. AND ITS CONTRIBUTORS ``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 ITS 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 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 "RenderTreeBuilder.h"
#include "AXObjectCache.h"
#include "DocumentInlines.h"
#include "Frame.h"
#include "FrameSelection.h"
#include "LegacyRenderSVGContainer.h"
#include "LegacyRenderSVGRoot.h"
#include "RenderButton.h"
#include "RenderCounter.h"
#include "RenderDescendantIterator.h"
#include "RenderElement.h"
#include "RenderEmbeddedObject.h"
#include "RenderFullScreen.h"
#include "RenderGrid.h"
#include "RenderHTMLCanvas.h"
#include "RenderLineBreak.h"
#include "RenderMathMLFenced.h"
#include "RenderMenuList.h"
#include "RenderMultiColumnFlow.h"
#include "RenderMultiColumnSpannerPlaceholder.h"
#include "RenderReplaced.h"
#include "RenderRuby.h"
#include "RenderRubyBase.h"
#include "RenderRubyRun.h"
#include "RenderSVGContainer.h"
#include "RenderSVGInline.h"
#include "RenderSVGRoot.h"
#include "RenderSVGText.h"
#include "RenderTable.h"
#include "RenderTableCell.h"
#include "RenderTableRow.h"
#include "RenderTableSection.h"
#include "RenderText.h"
#include "RenderTextFragment.h"
#include "RenderTreeBuilderBlock.h"
#include "RenderTreeBuilderBlockFlow.h"
#include "RenderTreeBuilderContinuation.h"
#include "RenderTreeBuilderFirstLetter.h"
#include "RenderTreeBuilderFormControls.h"
#include "RenderTreeBuilderFullScreen.h"
#include "RenderTreeBuilderInline.h"
#include "RenderTreeBuilderList.h"
#include "RenderTreeBuilderMathML.h"
#include "RenderTreeBuilderMultiColumn.h"
#include "RenderTreeBuilderRuby.h"
#include "RenderTreeBuilderSVG.h"
#include "RenderTreeBuilderTable.h"
#include "RenderTreeMutationDisallowedScope.h"
#include "RenderView.h"
#include <wtf/SetForScope.h>
#if ENABLE(LAYOUT_FORMATTING_CONTEXT)
#include "FrameView.h"
#include "FrameViewLayoutContext.h"
#include "RuntimeEnabledFeatures.h"
#endif
namespace WebCore {
RenderTreeBuilder* RenderTreeBuilder::s_current;
static void getInlineRun(RenderObject* start, RenderObject* boundary, RenderObject*& inlineRunStart, RenderObject*& inlineRunEnd)
{
// Beginning at |start| we find the largest contiguous run of inlines that
// we can. We denote the run with start and end points, |inlineRunStart|
// and |inlineRunEnd|. Note that these two values may be the same if
// we encounter only one inline.
//
// We skip any non-inlines we encounter as long as we haven't found any
// inlines yet.
//
// |boundary| indicates a non-inclusive boundary point. Regardless of whether |boundary|
// is inline or not, we will not include it in a run with inlines before it. It's as though we encountered
// a non-inline.
// Start by skipping as many non-inlines as we can.
auto* curr = start;
bool sawInline;
do {
while (curr && !(curr->isInline() || curr->isFloatingOrOutOfFlowPositioned()))
curr = curr->nextSibling();
inlineRunStart = inlineRunEnd = curr;
if (!curr)
return; // No more inline children to be found.
sawInline = curr->isInline();
curr = curr->nextSibling();
while (curr && (curr->isInline() || curr->isFloatingOrOutOfFlowPositioned()) && (curr != boundary)) {
inlineRunEnd = curr;
if (curr->isInline())
sawInline = true;
curr = curr->nextSibling();
}
} while (!sawInline);
}
RenderTreeBuilder::RenderTreeBuilder(RenderView& view)
: m_view(view)
, m_firstLetterBuilder(makeUnique<FirstLetter>(*this))
, m_listBuilder(makeUnique<List>(*this))
, m_multiColumnBuilder(makeUnique<MultiColumn>(*this))
, m_tableBuilder(makeUnique<Table>(*this))
, m_rubyBuilder(makeUnique<Ruby>(*this))
, m_formControlsBuilder(makeUnique<FormControls>(*this))
, m_blockBuilder(makeUnique<Block>(*this))
, m_blockFlowBuilder(makeUnique<BlockFlow>(*this))
, m_inlineBuilder(makeUnique<Inline>(*this))
, m_svgBuilder(makeUnique<SVG>(*this))
#if ENABLE(MATHML)
, m_mathMLBuilder(makeUnique<MathML>(*this))
#endif
, m_continuationBuilder(makeUnique<Continuation>(*this))
#if ENABLE(FULLSCREEN_API)
, m_fullScreenBuilder(makeUnique<FullScreen>(*this))
#endif
{
RELEASE_ASSERT(!s_current || &m_view != &s_current->m_view);
m_previous = s_current;
s_current = this;
}
RenderTreeBuilder::~RenderTreeBuilder()
{
s_current = m_previous;
}
void RenderTreeBuilder::destroy(RenderObject& renderer, CanCollapseAnonymousBlock canCollapseAnonymousBlock)
{
RELEASE_ASSERT(RenderTreeMutationDisallowedScope::isMutationAllowed());
ASSERT(renderer.parent());
auto toDestroy = detach(*renderer.parent(), renderer, canCollapseAnonymousBlock);
#if ENABLE(FULLSCREEN_API)
if (is<RenderFullScreen>(renderer))
fullScreenBuilder().cleanupOnDestroy(downcast<RenderFullScreen>(renderer));
#endif
if (is<RenderTextFragment>(renderer))
firstLetterBuilder().cleanupOnDestroy(downcast<RenderTextFragment>(renderer));
if (is<RenderBoxModelObject>(renderer))
continuationBuilder().cleanupOnDestroy(downcast<RenderBoxModelObject>(renderer));
// We need to detach the subtree first so that the descendants don't have
// access to previous/next sublings at detach().
// FIXME: webkit.org/b/182909.
if (!is<RenderElement>(toDestroy))
return;
auto& childToDestroy = downcast<RenderElement>(*toDestroy.get());
while (childToDestroy.firstChild()) {
auto& firstChild = *childToDestroy.firstChild();
if (auto* node = firstChild.node())
node->setRenderer(nullptr);
destroy(firstChild);
}
}
void RenderTreeBuilder::attach(RenderElement& parent, RenderPtr<RenderObject> child, RenderObject* beforeChild)
{
reportVisuallyNonEmptyContent(parent, *child);
attachInternal(parent, WTFMove(child), beforeChild);
}
void RenderTreeBuilder::attachInternal(RenderElement& parent, RenderPtr<RenderObject> child, RenderObject* beforeChild)
{
auto insertRecursiveIfNeeded = [&](RenderElement& parentCandidate) {
if (&parent == &parentCandidate) {
// Parents inside multicols can't call internal attach directly.
if (is<RenderBlockFlow>(parent) && downcast<RenderBlockFlow>(parent).multiColumnFlow()) {
blockFlowBuilder().attach(downcast<RenderBlockFlow>(parent), WTFMove(child), beforeChild);
return;
}
attachToRenderElement(parent, WTFMove(child), beforeChild);
return;
}
attachInternal(parentCandidate, WTFMove(child), beforeChild);
};
ASSERT(&parent.view() == &m_view);
if (is<RenderText>(beforeChild)) {
if (auto* wrapperInline = downcast<RenderText>(*beforeChild).inlineWrapperForDisplayContents())
beforeChild = wrapperInline;
} else if (is<RenderBox>(beforeChild)) {
// Adjust the beforeChild if it happens to be a spanner and the its actual location is inside the fragmented flow.
auto& beforeChildBox = downcast<RenderBox>(*beforeChild);
if (auto* enclosingFragmentedFlow = parent.enclosingFragmentedFlow()) {
auto columnSpannerPlaceholderForBeforeChild = [&]() -> RenderMultiColumnSpannerPlaceholder* {
if (!is<RenderMultiColumnFlow>(enclosingFragmentedFlow))
return nullptr;
auto& multiColumnFlow = downcast<RenderMultiColumnFlow>(*enclosingFragmentedFlow);
return multiColumnFlow.findColumnSpannerPlaceholder(&beforeChildBox);
};
if (auto* spannerPlaceholder = columnSpannerPlaceholderForBeforeChild())
beforeChild = spannerPlaceholder;
}
}
if (is<RenderTableRow>(parent)) {
auto& parentCandidate = tableBuilder().findOrCreateParentForChild(downcast<RenderTableRow>(parent), *child, beforeChild);
if (&parentCandidate == &parent) {
tableBuilder().attach(downcast<RenderTableRow>(parentCandidate), WTFMove(child), beforeChild);
return;
}
insertRecursiveIfNeeded(parentCandidate);
return;
}
if (is<RenderTableSection>(parent)) {
auto& parentCandidate = tableBuilder().findOrCreateParentForChild(downcast<RenderTableSection>(parent), *child, beforeChild);
if (&parent == &parentCandidate) {
tableBuilder().attach(downcast<RenderTableSection>(parent), WTFMove(child), beforeChild);
return;
}
insertRecursiveIfNeeded(parentCandidate);
return;
}
if (is<RenderTable>(parent)) {
auto& parentCandidate = tableBuilder().findOrCreateParentForChild(downcast<RenderTable>(parent), *child, beforeChild);
if (&parentCandidate == &parent) {
tableBuilder().attach(downcast<RenderTable>(parentCandidate), WTFMove(child), beforeChild);
return;
}
insertRecursiveIfNeeded(parentCandidate);
return;
}
if (is<RenderRubyAsBlock>(parent)) {
insertRecursiveIfNeeded(rubyBuilder().findOrCreateParentForChild(downcast<RenderRubyAsBlock>(parent), *child, beforeChild));
return;
}
if (is<RenderRubyAsInline>(parent)) {
insertRecursiveIfNeeded(rubyBuilder().findOrCreateParentForChild(downcast<RenderRubyAsInline>(parent), *child, beforeChild));
return;
}
if (is<RenderRubyRun>(parent)) {
rubyBuilder().attach(downcast<RenderRubyRun>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderButton>(parent)) {
formControlsBuilder().attach(downcast<RenderButton>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderMenuList>(parent)) {
formControlsBuilder().attach(downcast<RenderMenuList>(parent), WTFMove(child), beforeChild);
return;
}
#if ENABLE(LAYER_BASED_SVG_ENGINE)
if (is<RenderSVGContainer>(parent)) {
svgBuilder().attach(downcast<RenderSVGContainer>(parent), WTFMove(child), beforeChild);
return;
}
#endif
if (is<LegacyRenderSVGContainer>(parent)) {
svgBuilder().attach(downcast<LegacyRenderSVGContainer>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderSVGInline>(parent)) {
svgBuilder().attach(downcast<RenderSVGInline>(parent), WTFMove(child), beforeChild);
return;
}
#if ENABLE(LAYER_BASED_SVG_ENGINE)
if (is<RenderSVGRoot>(parent)) {
svgBuilder().attach(downcast<RenderSVGRoot>(parent), WTFMove(child), beforeChild);
return;
}
#endif
if (is<LegacyRenderSVGRoot>(parent)) {
svgBuilder().attach(downcast<LegacyRenderSVGRoot>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderSVGText>(parent)) {
svgBuilder().attach(downcast<RenderSVGText>(parent), WTFMove(child), beforeChild);
return;
}
#if ENABLE(MATHML)
if (is<RenderMathMLFenced>(parent)) {
mathMLBuilder().attach(downcast<RenderMathMLFenced>(parent), WTFMove(child), beforeChild);
return;
}
#endif
if (is<RenderGrid>(parent)) {
attachToRenderGrid(downcast<RenderGrid>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderBlockFlow>(parent)) {
blockFlowBuilder().attach(downcast<RenderBlockFlow>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderBlock>(parent)) {
blockBuilder().attach(downcast<RenderBlock>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderInline>(parent)) {
inlineBuilder().attach(downcast<RenderInline>(parent), WTFMove(child), beforeChild);
return;
}
attachToRenderElement(parent, WTFMove(child), beforeChild);
}
void RenderTreeBuilder::attachIgnoringContinuation(RenderElement& parent, RenderPtr<RenderObject> child, RenderObject* beforeChild)
{
if (is<RenderInline>(parent)) {
inlineBuilder().attachIgnoringContinuation(downcast<RenderInline>(parent), WTFMove(child), beforeChild);
return;
}
if (is<RenderBlock>(parent)) {
blockBuilder().attachIgnoringContinuation(downcast<RenderBlock>(parent), WTFMove(child), beforeChild);
return;
}
attachInternal(parent, WTFMove(child), beforeChild);
}
RenderPtr<RenderObject> RenderTreeBuilder::detach(RenderElement& parent, RenderObject& child, CanCollapseAnonymousBlock canCollapseAnonymousBlock)
{
if (is<RenderRubyAsInline>(parent))
return rubyBuilder().detach(downcast<RenderRubyAsInline>(parent), child);
if (is<RenderRubyAsBlock>(parent))
return rubyBuilder().detach(downcast<RenderRubyAsBlock>(parent), child);
if (is<RenderRubyRun>(parent))
return rubyBuilder().detach(downcast<RenderRubyRun>(parent), child);
if (is<RenderMenuList>(parent))
return formControlsBuilder().detach(downcast<RenderMenuList>(parent), child);
if (is<RenderButton>(parent))
return formControlsBuilder().detach(downcast<RenderButton>(parent), child);
if (is<RenderGrid>(parent))
return detachFromRenderGrid(downcast<RenderGrid>(parent), child);
if (is<RenderSVGText>(parent))
return svgBuilder().detach(downcast<RenderSVGText>(parent), child);
if (is<RenderSVGInline>(parent))
return svgBuilder().detach(downcast<RenderSVGInline>(parent), child);
#if ENABLE(LAYER_BASED_SVG_ENGINE)
if (is<RenderSVGContainer>(parent))
return svgBuilder().detach(downcast<RenderSVGContainer>(parent), child);
#endif
if (is<LegacyRenderSVGContainer>(parent))
return svgBuilder().detach(downcast<LegacyRenderSVGContainer>(parent), child);
#if ENABLE(LAYER_BASED_SVG_ENGINE)
if (is<RenderSVGRoot>(parent))
return svgBuilder().detach(downcast<RenderSVGRoot>(parent), child);
#endif
if (is<LegacyRenderSVGRoot>(parent))
return svgBuilder().detach(downcast<LegacyRenderSVGRoot>(parent), child);
if (is<RenderBlockFlow>(parent))
return blockBuilder().detach(downcast<RenderBlockFlow>(parent), child, canCollapseAnonymousBlock);
if (is<RenderBlock>(parent))
return blockBuilder().detach(downcast<RenderBlock>(parent), child, canCollapseAnonymousBlock);
return detachFromRenderElement(parent, child);
}
#if ENABLE(FULLSCREEN_API)
void RenderTreeBuilder::createPlaceholderForFullScreen(RenderFullScreen& renderer, std::unique_ptr<RenderStyle> style, const LayoutRect& frameRect)
{
fullScreenBuilder().createPlaceholder(renderer, WTFMove(style), frameRect);
}
#endif
void RenderTreeBuilder::attachToRenderElement(RenderElement& parent, RenderPtr<RenderObject> child, RenderObject* beforeChild)
{
if (tableBuilder().childRequiresTable(parent, *child)) {
RenderTable* table;
RenderObject* afterChild = beforeChild ? beforeChild->previousSibling() : parent.lastChild();
if (afterChild && afterChild->isAnonymous() && is<RenderTable>(*afterChild) && !afterChild->isBeforeContent())
table = downcast<RenderTable>(afterChild);
else {
auto newTable = RenderTable::createAnonymousWithParentRenderer(parent);
table = newTable.get();
attach(parent, WTFMove(newTable), beforeChild);
}
attach(*table, WTFMove(child));
return;
}
auto& newChild = *child.get();
attachToRenderElementInternal(parent, WTFMove(child), beforeChild);
parent.didAttachChild(newChild, beforeChild);
}
void RenderTreeBuilder::attachToRenderElementInternal(RenderElement& parent, RenderPtr<RenderObject> child, RenderObject* beforeChild, RenderObject::IsInternalMove isInternalMove)
{
RELEASE_ASSERT_WITH_MESSAGE(!parent.view().frameView().layoutContext().layoutState(), "Layout must not mutate render tree");
ASSERT(parent.canHaveChildren() || parent.canHaveGeneratedChildren());
ASSERT(!child->parent());
ASSERT(!parent.isRenderBlockFlow() || (!child->isTableSection() && !child->isTableRow() && !child->isTableCell()));
while (beforeChild && beforeChild->parent() && beforeChild->parent() != &parent)
beforeChild = beforeChild->parent();
ASSERT(!beforeChild || beforeChild->parent() == &parent);
ASSERT(!is<RenderText>(beforeChild) || !downcast<RenderText>(*beforeChild).inlineWrapperForDisplayContents());
// Take the ownership.
auto* newChild = parent.attachRendererInternal(WTFMove(child), beforeChild);
if (m_internalMovesType == RenderObject::IsInternalMove::No)
newChild->initializeFragmentedFlowStateOnInsertion();
if (!parent.renderTreeBeingDestroyed()) {
newChild->insertedIntoTree(isInternalMove);
if (m_internalMovesType == RenderObject::IsInternalMove::No) {
if (auto* fragmentedFlow = newChild->enclosingFragmentedFlow(); is<RenderMultiColumnFlow>(fragmentedFlow))
multiColumnBuilder().multiColumnDescendantInserted(downcast<RenderMultiColumnFlow>(*fragmentedFlow), *newChild);
if (is<RenderElement>(*newChild))
RenderCounter::rendererSubtreeAttached(downcast<RenderElement>(*newChild));
}
}
newChild->setNeedsLayoutAndPrefWidthsRecalc();
parent.setPreferredLogicalWidthsDirty(true);
if (!parent.normalChildNeedsLayout())
parent.setChildNeedsLayout(); // We may supply the static position for an absolute positioned child.
if (AXObjectCache* cache = parent.document().axObjectCache())
cache->childrenChanged(&parent, newChild);
if (parent.hasOutlineAutoAncestor() || parent.outlineStyleForRepaint().outlineStyleIsAuto() == OutlineIsAuto::On)
newChild->setHasOutlineAutoAncestor();
}
void RenderTreeBuilder::move(RenderBoxModelObject& from, RenderBoxModelObject& to, RenderObject& child, RenderObject* beforeChild, NormalizeAfterInsertion normalizeAfterInsertion)
{
// We assume that callers have cleared their positioned objects list for child moves so the
// positioned renderer maps don't become stale. It would be too slow to do the map lookup on each call.
ASSERT(normalizeAfterInsertion == NormalizeAfterInsertion::No || !is<RenderBlock>(from) || !downcast<RenderBlock>(from).hasPositionedObjects());
ASSERT(&from == child.parent());
ASSERT(!beforeChild || &to == beforeChild->parent());
if (normalizeAfterInsertion == NormalizeAfterInsertion::Yes && (to.isRenderBlock() || to.isRenderInline())) {
// Takes care of adding the new child correctly if toBlock and fromBlock
// have different kind of children (block vs inline).
auto childToMove = detachFromRenderElement(from, child);
attach(to, WTFMove(childToMove), beforeChild);
} else {
auto internalMoveScope = SetForScope { m_internalMovesType, RenderObject::IsInternalMove::Yes };
auto childToMove = detachFromRenderElement(from, child, WillBeDestroyed::No);
attachToRenderElementInternal(to, WTFMove(childToMove), beforeChild);
}
auto findBFCRootAndDestroyInlineTree = [&] {
auto* containingBlock = &from;
while (containingBlock) {
containingBlock->setNeedsLayout();
if (is<RenderBlockFlow>(*containingBlock)) {
downcast<RenderBlockFlow>(*containingBlock).deleteLines();
break;
}
containingBlock = containingBlock->containingBlock();
}
};
// When moving a subtree out of a BFC we need to make sure that the line boxes generated for the inline tree are not accessible anymore from the renderers.
// Let's find the BFC root and nuke the inline tree (At some point we are going to destroy the subtree instead of moving these renderers around.)
if (is<RenderInline>(child))
findBFCRootAndDestroyInlineTree();
}
void RenderTreeBuilder::move(RenderBoxModelObject& from, RenderBoxModelObject& to, RenderObject& child, NormalizeAfterInsertion normalizeAfterInsertion)
{
move(from, to, child, nullptr, normalizeAfterInsertion);
}
void RenderTreeBuilder::moveAllChildren(RenderBoxModelObject& from, RenderBoxModelObject& to, NormalizeAfterInsertion normalizeAfterInsertion)
{
moveAllChildren(from, to, nullptr, normalizeAfterInsertion);
}
void RenderTreeBuilder::moveAllChildren(RenderBoxModelObject& from, RenderBoxModelObject& to, RenderObject* beforeChild, NormalizeAfterInsertion normalizeAfterInsertion)
{
moveChildren(from, to, from.firstChild(), nullptr, beforeChild, normalizeAfterInsertion);
}
void RenderTreeBuilder::moveChildren(RenderBoxModelObject& from, RenderBoxModelObject& to, RenderObject* startChild, RenderObject* endChild, NormalizeAfterInsertion normalizeAfterInsertion)
{
moveChildren(from, to, startChild, endChild, nullptr, normalizeAfterInsertion);
}
void RenderTreeBuilder::moveChildren(RenderBoxModelObject& from, RenderBoxModelObject& to, RenderObject* startChild, RenderObject* endChild, RenderObject* beforeChild, NormalizeAfterInsertion normalizeAfterInsertion)
{
// This condition is rarely hit since this function is usually called on
// anonymous blocks which can no longer carry positioned objects (see r120761)
// or when fullRemoveInsert is false.
if (normalizeAfterInsertion == NormalizeAfterInsertion::Yes && is<RenderBlock>(from)) {
auto& blockFlow = downcast<RenderBlock>(from);
blockFlow.removePositionedObjects(nullptr);
removeFloatingObjects(blockFlow);
}
ASSERT(!beforeChild || &to == beforeChild->parent());
for (RenderObject* child = startChild; child && child != endChild; ) {
// Save our next sibling as moveChildTo will clear it.
RenderObject* nextSibling = child->nextSibling();
// FIXME: This logic here fails to detect the first letter in certain cases
// and skips a valid sibling renderer (see webkit.org/b/163737).
// Check to make sure we're not saving the firstLetter as the nextSibling.
// When the |child| object will be moved, its firstLetter will be recreated,
// so saving it now in nextSibling would leave us with a stale object.
if (is<RenderTextFragment>(*child) && is<RenderText>(nextSibling)) {
RenderObject* firstLetterObj = nullptr;
if (RenderBlock* block = downcast<RenderTextFragment>(*child).blockForAccompanyingFirstLetter()) {
RenderElement* firstLetterContainer = nullptr;
block->getFirstLetter(firstLetterObj, firstLetterContainer, child);
}
// This is the first letter, skip it.
if (firstLetterObj == nextSibling)
nextSibling = nextSibling->nextSibling();
}
move(from, to, *child, beforeChild, normalizeAfterInsertion);
child = nextSibling;
}
}
void RenderTreeBuilder::moveAllChildrenIncludingFloats(RenderBlock& from, RenderBlock& to, RenderTreeBuilder::NormalizeAfterInsertion normalizeAfterInsertion)
{
if (is<RenderBlockFlow>(from)) {
blockFlowBuilder().moveAllChildrenIncludingFloats(downcast<RenderBlockFlow>(from), to, normalizeAfterInsertion);
return;
}
moveAllChildren(from, to, normalizeAfterInsertion);
}
void RenderTreeBuilder::normalizeTreeAfterStyleChange(RenderElement& renderer, RenderStyle& oldStyle)
{
if (!renderer.parent())
return;
bool wasFloating = oldStyle.isFloating();
bool wasOutOfFlowPositioned = oldStyle.hasOutOfFlowPosition();
bool isFloating = renderer.style().isFloating();
bool isOutOfFlowPositioned = renderer.style().hasOutOfFlowPosition();
bool startsAffectingParent = false;
bool noLongerAffectsParent = false;
auto handleFragmentedFlowStateChange = [&] {
if (!renderer.parent())
return;
// Out of flow children of RenderMultiColumnFlow are not really part of the multicolumn flow. We need to ensure that changes in positioning like this
// trigger insertions into the multicolumn flow.
if (auto* enclosingFragmentedFlow = renderer.parent()->enclosingFragmentedFlow(); is<RenderMultiColumnFlow>(enclosingFragmentedFlow)) {
auto movingIntoMulticolumn = [&] {
if (wasOutOfFlowPositioned && !isOutOfFlowPositioned)
return true;
if (auto* containingBlock = renderer.containingBlock(); containingBlock && isOutOfFlowPositioned) {
// Sometimes the flow state could change even when the renderer stays out-of-flow (e.g when going from fixed to absolute and
// the containing block is inside a multi-column flow).
return containingBlock->fragmentedFlowState() == RenderObject::InsideInFragmentedFlow
&& renderer.fragmentedFlowState() == RenderObject::NotInsideFragmentedFlow;
}
return false;
}();
if (movingIntoMulticolumn) {
renderer.initializeFragmentedFlowStateOnInsertion();
multiColumnBuilder().multiColumnDescendantInserted(downcast<RenderMultiColumnFlow>(*enclosingFragmentedFlow), renderer);
return;
}
auto movingOutOfMulticolumn = !wasOutOfFlowPositioned && isOutOfFlowPositioned;
if (movingOutOfMulticolumn) {
multiColumnBuilder().restoreColumnSpannersForContainer(renderer, downcast<RenderMultiColumnFlow>(*enclosingFragmentedFlow));
return;
}
// Style change may have moved some subtree out of the fragmented flow. Their flow states have already been updated (see adjustFragmentedFlowStateOnContainingBlockChangeIfNeeded)
// and here is where we take care of the remaining, spanner tree mutation.
WeakHashSet<RenderElement> spannerContainingBlockSet;
for (auto& descendant : descendantsOfType<RenderMultiColumnSpannerPlaceholder>(renderer)) {
if (auto* containingBlock = descendant.containingBlock(); containingBlock && containingBlock->enclosingFragmentedFlow() != enclosingFragmentedFlow)
spannerContainingBlockSet.add(*containingBlock);
}
auto oldEnclosingFragmentedFlow = WeakPtr { *enclosingFragmentedFlow };
for (auto& containingBlock : spannerContainingBlockSet) {
if (!oldEnclosingFragmentedFlow)
break;
multiColumnBuilder().restoreColumnSpannersForContainer(containingBlock, downcast<RenderMultiColumnFlow>(*oldEnclosingFragmentedFlow));
}
}
};
auto& parent = *renderer.parent();
if (is<RenderBlock>(parent))
noLongerAffectsParent = (!wasFloating && isFloating) || (!wasOutOfFlowPositioned && isOutOfFlowPositioned);
if (is<RenderBlockFlow>(parent) || is<RenderInline>(parent)) {
startsAffectingParent = (wasFloating || wasOutOfFlowPositioned) && !isFloating && !isOutOfFlowPositioned;
ASSERT(!startsAffectingParent || !noLongerAffectsParent);
}
if (startsAffectingParent) {
// We have gone from not affecting the inline status of the parent flow to suddenly
// having an impact. See if there is a mismatch between the parent flow's
// childrenInline() state and our state.
if (renderer.isInline() != renderer.parent()->childrenInline())
childFlowStateChangesAndAffectsParentBlock(renderer);
// WARNING: original parent might be deleted at this point.
handleFragmentedFlowStateChange();
return;
}
if (noLongerAffectsParent) {
childFlowStateChangesAndNoLongerAffectsParentBlock(renderer);
if (isFloating && is<RenderBlockFlow>(renderer)) {
auto clearDescendantFloats = [&] {
// These descendent floats can not intrude other, sibling block containers anymore.
for (auto& descendant : descendantsOfType<RenderBox>(renderer)) {
if (descendant.isFloatingOrOutOfFlowPositioned())
descendant.removeFloatingOrPositionedChildFromBlockLists();
}
};
clearDescendantFloats();
downcast<RenderBlockFlow>(renderer).removeFloatingObjects();
// Fresh floats need to be reparented if they actually belong to the previous anonymous block.
// It copies the logic of RenderBlock::addChildIgnoringContinuation
if (renderer.previousSibling() && renderer.previousSibling()->isAnonymousBlock())
move(downcast<RenderBoxModelObject>(parent), downcast<RenderBoxModelObject>(*renderer.previousSibling()), renderer, RenderTreeBuilder::NormalizeAfterInsertion::No);
}
}
handleFragmentedFlowStateChange();
}
void RenderTreeBuilder::makeChildrenNonInline(RenderBlock& parent, RenderObject* insertionPoint)
{
// makeChildrenNonInline takes a block whose children are *all* inline and it
// makes sure that inline children are coalesced under anonymous
// blocks. If |insertionPoint| is defined, then it represents the insertion point for
// the new block child that is causing us to have to wrap all the inlines. This
// means that we cannot coalesce inlines before |insertionPoint| with inlines following
// |insertionPoint|, because the new child is going to be inserted in between the inlines,
// splitting them.
ASSERT(parent.isInlineBlockOrInlineTable() || !parent.isInline());
ASSERT(!insertionPoint || insertionPoint->parent() == &parent);
parent.setChildrenInline(false);
auto* child = parent.firstChild();
if (!child)
return;
parent.deleteLines();
while (child) {
RenderObject* inlineRunStart = nullptr;
RenderObject* inlineRunEnd = nullptr;
getInlineRun(child, insertionPoint, inlineRunStart, inlineRunEnd);
if (!inlineRunStart)
break;
child = inlineRunEnd->nextSibling();
auto newBlock = parent.createAnonymousBlock();
auto& block = *newBlock;
attachToRenderElementInternal(parent, WTFMove(newBlock), inlineRunStart);
moveChildren(parent, block, inlineRunStart, child, RenderTreeBuilder::NormalizeAfterInsertion::No);
}
#ifndef NDEBUG
for (RenderObject* c = parent.firstChild(); c; c = c->nextSibling())
ASSERT(!c->isInline());
#endif
parent.repaint();
}
RenderObject* RenderTreeBuilder::splitAnonymousBoxesAroundChild(RenderBox& parent, RenderObject& originalBeforeChild)
{
// Adjust beforeChild if it is a column spanner and has been moved out of its original position.
auto* beforeChild = RenderTreeBuilder::MultiColumn::adjustBeforeChildForMultiColumnSpannerIfNeeded(originalBeforeChild);
bool didSplitParentAnonymousBoxes = false;
while (beforeChild->parent() != &parent) {
auto& boxToSplit = downcast<RenderBox>(*beforeChild->parent());
if (boxToSplit.firstChild() != beforeChild && boxToSplit.isAnonymous()) {
didSplitParentAnonymousBoxes = true;
// We have to split the parent box into two boxes and move children
// from |beforeChild| to end into the new post box.
auto newPostBox = boxToSplit.createAnonymousBoxWithSameTypeAs(parent);
auto& postBox = *newPostBox;
postBox.setChildrenInline(boxToSplit.childrenInline());
RenderBox* parentBox = downcast<RenderBox>(boxToSplit.parent());
// We need to invalidate the |parentBox| before inserting the new node
// so that the table repainting logic knows the structure is dirty.
// See for example RenderTableCell:clippedOverflowRectForRepaint.
markBoxForRelayoutAfterSplit(*parentBox);
attachToRenderElementInternal(*parentBox, WTFMove(newPostBox), boxToSplit.nextSibling());
moveChildren(boxToSplit, postBox, beforeChild, nullptr, RenderTreeBuilder::NormalizeAfterInsertion::Yes);
markBoxForRelayoutAfterSplit(boxToSplit);
markBoxForRelayoutAfterSplit(postBox);
beforeChild = &postBox;
} else
beforeChild = &boxToSplit;
}
if (didSplitParentAnonymousBoxes)
markBoxForRelayoutAfterSplit(parent);
ASSERT(beforeChild->parent() == &parent);
return beforeChild;
}
void RenderTreeBuilder::childFlowStateChangesAndAffectsParentBlock(RenderElement& child)
{
if (!child.isInline()) {
WeakPtr parent = child.parent();
if (is<RenderBlock>(*parent))
blockBuilder().childBecameNonInline(downcast<RenderBlock>(*parent), child);
else if (is<RenderInline>(*parent))
inlineBuilder().childBecameNonInline(downcast<RenderInline>(*parent), child);
// WARNING: original parent might be deleted at this point.
if (auto* newParent = child.parent(); newParent != parent && is<RenderGrid>(newParent)) {
// We need to re-run the grid items placement if it had gained a new item.
downcast<RenderGrid>(*newParent).dirtyGrid();
}
return;
}
// An anonymous block must be made to wrap this inline.
auto* parent = child.parent();
auto newBlock = downcast<RenderBlock>(*parent).createAnonymousBlock();
auto& block = *newBlock;
attachToRenderElementInternal(*parent, WTFMove(newBlock), &child);
auto thisToMove = detachFromRenderElement(*parent, child);
attachToRenderElementInternal(block, WTFMove(thisToMove));
}
void RenderTreeBuilder::removeAnonymousWrappersForInlineChildrenIfNeeded(RenderElement& parent)
{
if (!is<RenderBlock>(parent))
return;
auto& blockParent = downcast<RenderBlock>(parent);
if (!blockParent.canDropAnonymousBlockChild())
return;
// We have changed to floated or out-of-flow positioning so maybe all our parent's
// children can be inline now. Bail if there are any block children left on the line,
// otherwise we can proceed to stripping solitary anonymous wrappers from the inlines.
// FIXME: We should also handle split inlines here - we exclude them at the moment by returning
// if we find a continuation.
std::optional<bool> shouldAllChildrenBeInline;
for (auto* current = blockParent.firstChild(); current; current = current->nextSibling()) {
if (current->style().isFloating() || current->style().hasOutOfFlowPosition())
continue;
if (!current->isAnonymousBlock() || downcast<RenderBlock>(*current).isContinuation())
return;
// Anonymous block not in continuation. Check if it holds a set of inline or block children and try not to mix them.
auto* firstChild = current->firstChildSlow();
if (!firstChild)
continue;
auto isInlineLevelBox = firstChild->isInline();
if (!shouldAllChildrenBeInline.has_value()) {
shouldAllChildrenBeInline = isInlineLevelBox;
continue;
}
// Mixing inline and block level boxes?
if (*shouldAllChildrenBeInline != isInlineLevelBox)
return;
}
RenderObject* next = nullptr;
for (auto* current = blockParent.firstChild(); current; current = next) {
next = current->nextSibling();
if (current->isAnonymousBlock())
blockBuilder().dropAnonymousBoxChild(blockParent, downcast<RenderBlock>(*current));
}
}
void RenderTreeBuilder::childFlowStateChangesAndNoLongerAffectsParentBlock(RenderElement& child)
{
ASSERT(child.parent());
removeAnonymousWrappersForInlineChildrenIfNeeded(*child.parent());
}
void RenderTreeBuilder::destroyAndCleanUpAnonymousWrappers(RenderObject& rendererToDestroy)
{
// If the tree is destroyed, there is no need for a clean-up phase.
if (rendererToDestroy.renderTreeBeingDestroyed()) {
destroy(rendererToDestroy);
return;
}
// Also destroy ::backdrop along with element if there is one
if (is<RenderElement>(rendererToDestroy)) {
if (auto backdropRenderer = downcast<RenderElement>(rendererToDestroy).backdropRenderer())
destroy(*backdropRenderer);
}
auto isAnonymousAndSafeToDelete = [] (const auto& renderer) {
return renderer.isAnonymous() && !is<RenderRubyBase>(renderer) && !renderer.isRenderView() && !renderer.isRenderFragmentedFlow();
};
auto destroyRootIncludingAnonymous = [&] () -> RenderObject& {
auto* destroyRoot = &rendererToDestroy;
while (!is<RenderView>(*destroyRoot)) {
auto& destroyRootParent = *destroyRoot->parent();
if (!isAnonymousAndSafeToDelete(destroyRootParent))
break;
bool destroyingOnlyChild = destroyRootParent.firstChild() == destroyRoot && destroyRootParent.lastChild() == destroyRoot;
if (!destroyingOnlyChild)
break;
destroyRoot = &destroyRootParent;
}
return *destroyRoot;
};
auto& destroyRoot = destroyRootIncludingAnonymous();
auto clearFloatsAndOutOfFlowPositionedObjects = [&] {
// Remove floats and out-of-flow positioned objects from their containing block before detaching
// the renderer from the tree. It includes all the anonymous block descendants that we are about
// to destroy as well as part of the cleanup process below.
if (!is<RenderElement>(destroyRoot))
return;
for (auto& descendant : descendantsOfType<RenderBox>(downcast<RenderElement>(destroyRoot))) {
if (descendant.isFloatingOrOutOfFlowPositioned())
descendant.removeFloatingOrPositionedChildFromBlockLists();
}
if (is<RenderBox>(destroyRoot) && destroyRoot.isFloatingOrOutOfFlowPositioned())
downcast<RenderBox>(destroyRoot).removeFloatingOrPositionedChildFromBlockLists();
};
clearFloatsAndOutOfFlowPositionedObjects();
auto collapseAndDestroyAnonymousSiblings = [&] {
// FIXME: Probably need to handle other table parts here as well.
if (is<RenderTableCell>(destroyRoot)) {
tableBuilder().collapseAndDestroyAnonymousSiblingCells(downcast<RenderTableCell>(destroyRoot));
return;
}
if (is<RenderTableRow>(destroyRoot)) {
tableBuilder().collapseAndDestroyAnonymousSiblingRows(downcast<RenderTableRow>(destroyRoot));
return;
}
};
collapseAndDestroyAnonymousSiblings();
// FIXME: Do not try to collapse/cleanup the anonymous wrappers inside destroy (see webkit.org/b/186746).
WeakPtr destroyRootParent = *destroyRoot.parent();
if (&rendererToDestroy != &destroyRoot) {
// Destroy the child renderer first, before we start tearing down the anonymous wrapper ancestor chain.
destroy(rendererToDestroy);
}
destroy(destroyRoot);
if (!destroyRootParent)
return;
removeAnonymousWrappersForInlineChildrenIfNeeded(*destroyRootParent);
// Anonymous parent might have become empty, try to delete it too.
if (isAnonymousAndSafeToDelete(*destroyRootParent) && !destroyRootParent->firstChild())
destroyAndCleanUpAnonymousWrappers(*destroyRootParent);
// WARNING: rendererToDestroy is deleted here.
}
void RenderTreeBuilder::updateAfterDescendants(RenderElement& renderer)
{
if (is<RenderBlock>(renderer))
firstLetterBuilder().updateAfterDescendants(downcast<RenderBlock>(renderer));
if (is<RenderListItem>(renderer))
listBuilder().updateItemMarker(downcast<RenderListItem>(renderer));
if (is<RenderBlockFlow>(renderer))
multiColumnBuilder().updateAfterDescendants(downcast<RenderBlockFlow>(renderer));
}
RenderPtr<RenderObject> RenderTreeBuilder::detachFromRenderGrid(RenderGrid& parent, RenderObject& child)
{
auto takenChild = blockBuilder().detach(parent, child);
// Positioned grid items do not take up space or otherwise participate in the layout of the grid,
// for that reason we don't need to mark the grid as dirty when they are removed.
if (child.isOutOfFlowPositioned())
return takenChild;
// The grid needs to be recomputed as it might contain auto-placed items that will change their position.
parent.dirtyGrid();
return takenChild;
}
RenderPtr<RenderObject> RenderTreeBuilder::detachFromRenderElement(RenderElement& parent, RenderObject& child, WillBeDestroyed willBeDestroyed)
{
RELEASE_ASSERT_WITH_MESSAGE(!parent.view().frameView().layoutContext().layoutState(), "Layout must not mutate render tree");
ASSERT(parent.canHaveChildren() || parent.canHaveGeneratedChildren());
ASSERT(child.parent() == &parent);
if (child.isFloatingOrOutOfFlowPositioned())
downcast<RenderBox>(child).removeFloatingOrPositionedChildFromBlockLists();
// So that we'll get the appropriate dirty bit set (either that a normal flow child got yanked or
// that a positioned child got yanked). We also repaint, so that the area exposed when the child
// disappears gets repainted properly.
if (!parent.renderTreeBeingDestroyed() && child.everHadLayout()) {
child.setNeedsLayoutAndPrefWidthsRecalc();
// We only repaint |child| if we have a RenderLayer as its visual overflow may not be tracked by its parent.
if (child.isBody())
parent.view().repaintRootContents();
else
child.repaint();
}
// If we have a line box wrapper, delete it.
if (is<RenderBox>(child))
downcast<RenderBox>(child).deleteLineBoxWrapper();
else if (is<RenderLineBreak>(child))
downcast<RenderLineBreak>(child).deleteInlineBoxWrapper();
else if (is<RenderText>(child))
downcast<RenderText>(child).removeAndDestroyTextBoxes();
if (!parent.renderTreeBeingDestroyed() && is<RenderFlexibleBox>(parent) && !child.isFloatingOrOutOfFlowPositioned() && child.isBox())
downcast<RenderFlexibleBox>(parent).clearCachedChildIntrinsicContentLogicalHeight(downcast<RenderBox>(child));
// If child is the start or end of the selection, then clear the selection to
// avoid problems of invalid pointers.
if (!parent.renderTreeBeingDestroyed() && willBeDestroyed == WillBeDestroyed::Yes && child.isSelectionBorder())
parent.frame().selection().setNeedsSelectionUpdate();
if (!parent.renderTreeBeingDestroyed() && m_internalMovesType == RenderObject::IsInternalMove::No)
child.resetFragmentedFlowStateOnRemoval();
if (!parent.renderTreeBeingDestroyed())
child.willBeRemovedFromTree(m_internalMovesType);
// WARNING: There should be no code running between willBeRemovedFromTree() and the actual removal below.
// This is needed to avoid race conditions where willBeRemovedFromTree() would dirty the tree's structure
// and the code running here would force an untimely rebuilding, leaving |child| dangling.
auto childToTake = parent.detachRendererInternal(child);
// rendererRemovedFromTree() walks the whole subtree. We can improve performance
// by skipping this step when destroying the entire tree.
if (!parent.renderTreeBeingDestroyed() && is<RenderElement>(*childToTake))
RenderCounter::rendererRemovedFromTree(downcast<RenderElement>(*childToTake));
if (!parent.renderTreeBeingDestroyed()) {
if (AXObjectCache* cache = parent.document().existingAXObjectCache())
cache->childrenChanged(&parent);
}
return childToTake;