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/*
* Copyright (C) 2016-2017 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 "RenderTreeUpdater.h"
#include "AXObjectCache.h"
#include "CSSAnimationController.h"
#include "ComposedTreeAncestorIterator.h"
#include "ComposedTreeIterator.h"
#include "Document.h"
#include "DocumentTimeline.h"
#include "Element.h"
#include "HTMLParserIdioms.h"
#include "HTMLSlotElement.h"
#include "InspectorInstrumentation.h"
#include "NodeRenderStyle.h"
#include "PseudoElement.h"
#include "RenderDescendantIterator.h"
#include "RenderFullScreen.h"
#include "RenderInline.h"
#include "RenderTreeUpdaterGeneratedContent.h"
#include "RuntimeEnabledFeatures.h"
#include "StyleResolver.h"
#include "StyleTreeResolver.h"
#include <wtf/SystemTracing.h>
#if PLATFORM(IOS)
#include "WKContentObservation.h"
#include "WKContentObservationInternal.h"
#endif
namespace WebCore {
#if PLATFORM(IOS)
class CheckForVisibilityChange {
public:
CheckForVisibilityChange(const Element&);
~CheckForVisibilityChange();
private:
const Element& m_element;
EDisplay m_previousDisplay;
EVisibility m_previousVisibility;
EVisibility m_previousImplicitVisibility;
};
#endif // PLATFORM(IOS)
RenderTreeUpdater::Parent::Parent(ContainerNode& root)
: element(is<Document>(root) ? nullptr : downcast<Element>(&root))
, renderTreePosition(RenderTreePosition(*root.renderer()))
{
}
RenderTreeUpdater::Parent::Parent(Element& element, const Style::ElementUpdates* updates)
: element(&element)
, updates(updates)
, renderTreePosition(element.renderer() ? std::make_optional(RenderTreePosition(*element.renderer())) : std::nullopt)
{
}
RenderTreeUpdater::RenderTreeUpdater(Document& document)
: m_document(document)
, m_generatedContent(std::make_unique<GeneratedContent>(*this))
, m_builder(renderView())
{
}
RenderTreeUpdater::~RenderTreeUpdater() = default;
static ContainerNode* findRenderingRoot(ContainerNode& node)
{
if (node.renderer())
return &node;
for (auto& ancestor : composedTreeAncestors(node)) {
if (ancestor.renderer())
return &ancestor;
if (!ancestor.hasDisplayContents())
return nullptr;
}
return &node.document();
}
static ListHashSet<ContainerNode*> findRenderingRoots(const Style::Update& update)
{
ListHashSet<ContainerNode*> renderingRoots;
for (auto* root : update.roots()) {
auto* renderingRoot = findRenderingRoot(*root);
if (!renderingRoot)
continue;
renderingRoots.add(renderingRoot);
}
return renderingRoots;
}
void RenderTreeUpdater::commit(std::unique_ptr<const Style::Update> styleUpdate)
{
ASSERT(&m_document == &styleUpdate->document());
if (!m_document.shouldCreateRenderers() || !m_document.renderView())
return;
TraceScope scope(RenderTreeBuildStart, RenderTreeBuildEnd);
Style::PostResolutionCallbackDisabler callbackDisabler(m_document);
m_styleUpdate = WTFMove(styleUpdate);
for (auto* root : findRenderingRoots(*m_styleUpdate))
updateRenderTree(*root);
generatedContent().updateRemainingQuotes();
m_builder.updateAfterDescendants(renderView());
m_styleUpdate = nullptr;
}
static bool shouldCreateRenderer(const Element& element, const RenderElement& parentRenderer)
{
if (!parentRenderer.canHaveChildren() && !(element.isPseudoElement() && parentRenderer.canHaveGeneratedChildren()))
return false;
if (parentRenderer.element() && !parentRenderer.element()->childShouldCreateRenderer(element))
return false;
return true;
}
void RenderTreeUpdater::updateRenderTree(ContainerNode& root)
{
ASSERT(root.renderer());
ASSERT(m_parentStack.isEmpty());
m_parentStack.append(Parent(root));
auto descendants = composedTreeDescendants(root);
auto it = descendants.begin();
auto end = descendants.end();
// FIXME: https://bugs.webkit.org/show_bug.cgi?id=156172
it.dropAssertions();
while (it != end) {
popParentsToDepth(it.depth());
auto& node = *it;
if (auto* renderer = node.renderer())
renderTreePosition().invalidateNextSibling(*renderer);
else if (is<Element>(node) && downcast<Element>(node).hasDisplayContents())
renderTreePosition().invalidateNextSibling();
if (is<Text>(node)) {
auto& text = downcast<Text>(node);
auto* textUpdate = m_styleUpdate->textUpdate(text);
bool didCreateParent = parent().updates && parent().updates->update.change == Style::Detach;
bool mayNeedUpdateWhitespaceOnlyRenderer = renderingParent().didCreateOrDestroyChildRenderer && text.data().isAllSpecialCharacters<isHTMLSpace>();
if (didCreateParent || textUpdate || mayNeedUpdateWhitespaceOnlyRenderer)
updateTextRenderer(text, textUpdate);
storePreviousRenderer(text);
it.traverseNextSkippingChildren();
continue;
}
auto& element = downcast<Element>(node);
auto* elementUpdates = m_styleUpdate->elementUpdates(element);
// We hop through display: contents elements in findRenderingRoot, so
// there may be other updates down the tree.
if (!elementUpdates && !element.hasDisplayContents()) {
storePreviousRenderer(element);
it.traverseNextSkippingChildren();
continue;
}
if (elementUpdates)
updateElementRenderer(element, elementUpdates->update);
storePreviousRenderer(element);
bool mayHaveRenderedDescendants = element.renderer() || (element.hasDisplayContents() && shouldCreateRenderer(element, renderTreePosition().parent()));
if (!mayHaveRenderedDescendants) {
it.traverseNextSkippingChildren();
continue;
}
pushParent(element, elementUpdates);
it.traverseNext();
}
popParentsToDepth(0);
}
auto RenderTreeUpdater::renderingParent() -> Parent&
{
for (unsigned i = m_parentStack.size(); i--;) {
if (m_parentStack[i].renderTreePosition)
return m_parentStack[i];
}
ASSERT_NOT_REACHED();
return m_parentStack.last();
}
RenderTreePosition& RenderTreeUpdater::renderTreePosition()
{
return *renderingParent().renderTreePosition;
}
void RenderTreeUpdater::pushParent(Element& element, const Style::ElementUpdates* updates)
{
m_parentStack.append(Parent(element, updates));
updateBeforeDescendants(element, updates);
}
void RenderTreeUpdater::popParent()
{
auto& parent = m_parentStack.last();
if (parent.element)
updateAfterDescendants(*parent.element, parent.updates);
m_parentStack.removeLast();
}
void RenderTreeUpdater::popParentsToDepth(unsigned depth)
{
ASSERT(m_parentStack.size() >= depth);
while (m_parentStack.size() > depth)
popParent();
}
void RenderTreeUpdater::updateBeforeDescendants(Element& element, const Style::ElementUpdates* updates)
{
if (updates)
generatedContent().updatePseudoElement(element, updates->beforePseudoElementUpdate, BEFORE);
}
void RenderTreeUpdater::updateAfterDescendants(Element& element, const Style::ElementUpdates* updates)
{
if (updates)
generatedContent().updatePseudoElement(element, updates->afterPseudoElementUpdate, AFTER);
auto* renderer = element.renderer();
if (!renderer)
return;
m_builder.updateAfterDescendants(*renderer);
if (element.hasCustomStyleResolveCallbacks() && updates && updates->update.change == Style::Detach)
element.didAttachRenderers();
}
static bool pseudoStyleCacheIsInvalid(RenderElement* renderer, RenderStyle* newStyle)
{
const RenderStyle& currentStyle = renderer->style();
const PseudoStyleCache* pseudoStyleCache = currentStyle.cachedPseudoStyles();
if (!pseudoStyleCache)
return false;
for (auto& cache : *pseudoStyleCache) {
PseudoId pseudoId = cache->styleType();
std::unique_ptr<RenderStyle> newPseudoStyle = renderer->getUncachedPseudoStyle(PseudoStyleRequest(pseudoId), newStyle, newStyle);
if (!newPseudoStyle)
return true;
if (*newPseudoStyle != *cache) {
newStyle->addCachedPseudoStyle(WTFMove(newPseudoStyle));
return true;
}
}
return false;
}
void RenderTreeUpdater::updateRendererStyle(RenderElement& renderer, RenderStyle&& newStyle, StyleDifference minimalStyleDifference)
{
auto oldStyle = RenderStyle::clone(renderer.style());
renderer.setStyle(WTFMove(newStyle), minimalStyleDifference);
m_builder.normalizeTreeAfterStyleChange(renderer, oldStyle);
}
void RenderTreeUpdater::updateElementRenderer(Element& element, const Style::ElementUpdate& update)
{
#if PLATFORM(IOS)
CheckForVisibilityChange checkForVisibilityChange(element);
#endif
bool shouldTearDownRenderers = update.change == Style::Detach && (element.renderer() || element.hasDisplayContents());
if (shouldTearDownRenderers) {
if (!element.renderer()) {
// We may be tearing down a descendant renderer cached in renderTreePosition.
renderTreePosition().invalidateNextSibling();
}
// display:none cancels animations.
auto teardownType = update.style->display() == NONE ? TeardownType::RendererUpdateCancelingAnimations : TeardownType::RendererUpdate;
tearDownRenderers(element, teardownType, m_builder);
renderingParent().didCreateOrDestroyChildRenderer = true;
}
bool hasDisplayContents = update.style->display() == CONTENTS;
if (hasDisplayContents)
element.storeDisplayContentsStyle(RenderStyle::clonePtr(*update.style));
else
element.resetComputedStyle();
bool shouldCreateNewRenderer = !element.renderer() && !hasDisplayContents;
if (shouldCreateNewRenderer) {
if (element.hasCustomStyleResolveCallbacks())
element.willAttachRenderers();
createRenderer(element, RenderStyle::clone(*update.style));
renderingParent().didCreateOrDestroyChildRenderer = true;
return;
}
if (!element.renderer())
return;
auto& renderer = *element.renderer();
if (update.recompositeLayer) {
updateRendererStyle(renderer, RenderStyle::clone(*update.style), StyleDifferenceRecompositeLayer);
return;
}
if (update.change == Style::NoChange) {
if (pseudoStyleCacheIsInvalid(&renderer, update.style.get())) {
updateRendererStyle(renderer, RenderStyle::clone(*update.style), StyleDifferenceEqual);
return;
}
return;
}
updateRendererStyle(renderer, RenderStyle::clone(*update.style), StyleDifferenceEqual);
}
void RenderTreeUpdater::createRenderer(Element& element, RenderStyle&& style)
{
auto computeInsertionPosition = [this, &element] () {
renderTreePosition().computeNextSibling(element);
return renderTreePosition();
};
if (!shouldCreateRenderer(element, renderTreePosition().parent()))
return;
if (!element.rendererIsNeeded(style))
return;
RenderTreePosition insertionPosition = computeInsertionPosition();
auto newRenderer = element.createElementRenderer(WTFMove(style), insertionPosition);
if (!newRenderer)
return;
if (!insertionPosition.parent().isChildAllowed(*newRenderer, newRenderer->style()))
return;
element.setRenderer(newRenderer.get());
newRenderer->initializeStyle();
#if ENABLE(FULLSCREEN_API)
if (m_document.webkitIsFullScreen() && m_document.webkitCurrentFullScreenElement() == &element) {
newRenderer = RenderFullScreen::wrapNewRenderer(m_builder, WTFMove(newRenderer), insertionPosition.parent(), m_document);
if (!newRenderer)
return;
}
#endif
m_builder.attach(insertionPosition, WTFMove(newRenderer));
if (AXObjectCache* cache = m_document.axObjectCache())
cache->updateCacheAfterNodeIsAttached(&element);
}
bool RenderTreeUpdater::textRendererIsNeeded(const Text& textNode)
{
auto& renderingParent = this->renderingParent();
auto& parentRenderer = renderingParent.renderTreePosition->parent();
if (!parentRenderer.canHaveChildren())
return false;
if (parentRenderer.element() && !parentRenderer.element()->childShouldCreateRenderer(textNode))
return false;
if (textNode.isEditingText())
return true;
if (!textNode.length())
return false;
if (!textNode.data().isAllSpecialCharacters<isHTMLSpace>())
return true;
if (is<RenderText>(renderingParent.previousChildRenderer))
return true;
// This text node has nothing but white space. We may still need a renderer in some cases.
if (parentRenderer.isTable() || parentRenderer.isTableRow() || parentRenderer.isTableSection() || parentRenderer.isRenderTableCol() || parentRenderer.isFrameSet())
return false;
if (parentRenderer.isFlexibleBox() && !parentRenderer.isRenderButton())
return false;
if (parentRenderer.style().preserveNewline()) // pre/pre-wrap/pre-line always make renderers.
return true;
auto* previousRenderer = renderingParent.previousChildRenderer;
if (previousRenderer && previousRenderer->isBR()) // <span><br/> <br/></span>
return false;
if (parentRenderer.isRenderInline()) {
// <span><div/> <div/></span>
if (previousRenderer && !previousRenderer->isInline())
return false;
} else {
if (parentRenderer.isRenderBlock() && !parentRenderer.childrenInline() && (!previousRenderer || !previousRenderer->isInline()))
return false;
RenderObject* first = parentRenderer.firstChild();
while (first && first->isFloatingOrOutOfFlowPositioned())
first = first->nextSibling();
RenderObject* nextRenderer = textNode.renderer() ? textNode.renderer() : renderTreePosition().nextSiblingRenderer(textNode);
if (!first || nextRenderer == first) {
// Whitespace at the start of a block just goes away. Don't even make a render object for this text.
return false;
}
}
return true;
}
void RenderTreeUpdater::createTextRenderer(Text& textNode, const Style::TextUpdate* textUpdate)
{
ASSERT(!textNode.renderer());
auto& renderTreePosition = this->renderTreePosition();
auto textRenderer = textNode.createTextRenderer(renderTreePosition.parent().style());
renderTreePosition.computeNextSibling(textNode);
if (!renderTreePosition.parent().isChildAllowed(*textRenderer, renderTreePosition.parent().style()))
return;
textNode.setRenderer(textRenderer.get());
if (textUpdate && textUpdate->inheritedDisplayContentsStyle && *textUpdate->inheritedDisplayContentsStyle) {
// Wrap text renderer into anonymous inline so we can give it a style.
// This is to support "<div style='display:contents;color:green'>text</div>" type cases
auto newDisplayContentsAnonymousWrapper = WebCore::createRenderer<RenderInline>(textNode.document(), RenderStyle::clone(**textUpdate->inheritedDisplayContentsStyle));
newDisplayContentsAnonymousWrapper->initializeStyle();
auto& displayContentsAnonymousWrapper = *newDisplayContentsAnonymousWrapper;
m_builder.attach(renderTreePosition, WTFMove(newDisplayContentsAnonymousWrapper));
textRenderer->setInlineWrapperForDisplayContents(&displayContentsAnonymousWrapper);
m_builder.attach(displayContentsAnonymousWrapper, WTFMove(textRenderer));
return;
}
m_builder.attach(renderTreePosition, WTFMove(textRenderer));
}
void RenderTreeUpdater::updateTextRenderer(Text& text, const Style::TextUpdate* textUpdate)
{
auto* existingRenderer = text.renderer();
bool needsRenderer = textRendererIsNeeded(text);
if (existingRenderer && textUpdate && textUpdate->inheritedDisplayContentsStyle) {
if (existingRenderer->inlineWrapperForDisplayContents() || *textUpdate->inheritedDisplayContentsStyle) {
// FIXME: We could update without teardown.
tearDownTextRenderer(text, m_builder);
existingRenderer = nullptr;
}
}
if (existingRenderer) {
if (needsRenderer) {
if (textUpdate)
existingRenderer->setTextWithOffset(text.data(), textUpdate->offset, textUpdate->length);
return;
}
tearDownTextRenderer(text, m_builder);
renderingParent().didCreateOrDestroyChildRenderer = true;
return;
}
if (!needsRenderer)
return;
createTextRenderer(text, textUpdate);
renderingParent().didCreateOrDestroyChildRenderer = true;
}
void RenderTreeUpdater::storePreviousRenderer(Node& node)
{
auto* renderer = node.renderer();
if (!renderer)
return;
ASSERT(renderingParent().previousChildRenderer != renderer);
renderingParent().previousChildRenderer = renderer;
}
void RenderTreeUpdater::tearDownRenderers(Element& root)
{
auto* view = root.document().renderView();
if (!view)
return;
RenderTreeBuilder builder(*view);
tearDownRenderers(root, TeardownType::Full, builder);
}
void RenderTreeUpdater::tearDownRenderer(Text& text)
{
auto* view = text.document().renderView();
if (!view)
return;
RenderTreeBuilder builder(*view);
tearDownTextRenderer(text, builder);
}
void RenderTreeUpdater::tearDownRenderers(Element& root, TeardownType teardownType, RenderTreeBuilder& builder)
{
WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
Vector<Element*, 30> teardownStack;
auto push = [&] (Element& element) {
if (element.hasCustomStyleResolveCallbacks())
element.willDetachRenderers();
teardownStack.append(&element);
};
auto& document = root.document();
auto* timeline = document.existingTimeline();
auto& animationController = document.frame()->animation();
auto pop = [&] (unsigned depth) {
while (teardownStack.size() > depth) {
auto& element = *teardownStack.takeLast();
if (teardownType == TeardownType::Full || teardownType == TeardownType::RendererUpdateCancelingAnimations) {
if (RuntimeEnabledFeatures::sharedFeatures().cssAnimationsAndCSSTransitionsBackedByWebAnimationsEnabled()) {
if (timeline)
timeline->cancelDeclarativeAnimationsForElement(element);
} else
animationController.cancelAnimations(element);
}
if (teardownType == TeardownType::Full)
element.clearHoverAndActiveStatusBeforeDetachingRenderer();
GeneratedContent::removeBeforePseudoElement(element, builder);
GeneratedContent::removeAfterPseudoElement(element, builder);
if (auto* renderer = element.renderer()) {
builder.destroyAndCleanUpAnonymousWrappers(*renderer);
element.setRenderer(nullptr);
}
// Make sure we don't leave any renderers behind in nodes outside the composed tree.
if (element.shadowRoot())
tearDownLeftoverShadowHostChildren(element, builder);
if (element.hasCustomStyleResolveCallbacks())
element.didDetachRenderers();
}
};
push(root);
auto descendants = composedTreeDescendants(root);
for (auto it = descendants.begin(), end = descendants.end(); it != end; ++it) {
pop(it.depth());
if (is<Text>(*it)) {
tearDownTextRenderer(downcast<Text>(*it), builder);
continue;
}
push(downcast<Element>(*it));
}
pop(0);
tearDownLeftoverPaginationRenderersIfNeeded(root, builder);
}
void RenderTreeUpdater::tearDownTextRenderer(Text& text, RenderTreeBuilder& builder)
{
auto* renderer = text.renderer();
if (!renderer)
return;
builder.destroyAndCleanUpAnonymousWrappers(*renderer);
text.setRenderer(nullptr);
}
void RenderTreeUpdater::tearDownLeftoverPaginationRenderersIfNeeded(Element& root, RenderTreeBuilder& builder)
{
if (&root != root.document().documentElement())
return;
for (auto* child = root.document().renderView()->firstChild(); child;) {
auto* nextSibling = child->nextSibling();
if (is<RenderMultiColumnFlow>(*child) || is<RenderMultiColumnSet>(*child))
builder.destroyAndCleanUpAnonymousWrappers(*child);
child = nextSibling;
}
}
void RenderTreeUpdater::tearDownLeftoverShadowHostChildren(Element& host, RenderTreeBuilder& builder)
{
for (auto* hostChild = host.firstChild(); hostChild; hostChild = hostChild->nextSibling()) {
if (!hostChild->renderer())
continue;
if (is<Text>(*hostChild)) {
tearDownTextRenderer(downcast<Text>(*hostChild), builder);
continue;
}
if (is<Element>(*hostChild))
tearDownRenderers(downcast<Element>(*hostChild), TeardownType::Full, builder);
}
}
RenderView& RenderTreeUpdater::renderView()
{
return *m_document.renderView();
}
#if PLATFORM(IOS)
static EVisibility elementImplicitVisibility(const Element& element)
{
auto* renderer = element.renderer();
if (!renderer)
return VISIBLE;
auto& style = renderer->style();
auto width = style.width();
auto height = style.height();
if ((width.isFixed() && width.value() <= 0) || (height.isFixed() && height.value() <= 0))
return HIDDEN;
auto top = style.top();
auto left = style.left();
if (left.isFixed() && width.isFixed() && -left.value() >= width.value())
return HIDDEN;
if (top.isFixed() && height.isFixed() && -top.value() >= height.value())
return HIDDEN;
return VISIBLE;
}
CheckForVisibilityChange::CheckForVisibilityChange(const Element& element)
: m_element(element)
, m_previousDisplay(element.renderStyle() ? element.renderStyle()->display() : NONE)
, m_previousVisibility(element.renderStyle() ? element.renderStyle()->visibility() : HIDDEN)
, m_previousImplicitVisibility(WKObservingContentChanges() && WKObservedContentChange() != WKContentVisibilityChange ? elementImplicitVisibility(element) : VISIBLE)
{
}
CheckForVisibilityChange::~CheckForVisibilityChange()
{
if (!WKObservingContentChanges())
return;
if (m_element.isInUserAgentShadowTree())
return;
auto* style = m_element.renderStyle();
if (!style)
return;
if ((m_previousDisplay == NONE && style->display() != NONE) || (m_previousVisibility == HIDDEN && style->visibility() != HIDDEN)
|| (m_previousImplicitVisibility == HIDDEN && elementImplicitVisibility(m_element) == VISIBLE))
WKSetObservedContentChange(WKContentVisibilityChange);
}
#endif
}