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/*
* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
* (C) 1999 Antti Koivisto (koivisto@kde.org)
* (C) 2001 Peter Kelly (pmk@post.com)
* (C) 2001 Dirk Mueller (mueller@kde.org)
* (C) 2007 David Smith (catfish.man@gmail.com)
* Copyright (C) 2004-2010, 2012-2016 Apple Inc. All rights reserved.
* (C) 2007 Eric Seidel (eric@webkit.org)
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "config.h"
#include "StyleTreeResolver.h"
#include "CSSAnimationController.h"
#include "CSSFontSelector.h"
#include "ComposedTreeAncestorIterator.h"
#include "ComposedTreeIterator.h"
#include "DocumentTimeline.h"
#include "ElementIterator.h"
#include "Frame.h"
#include "HTMLBodyElement.h"
#include "HTMLMeterElement.h"
#include "HTMLNames.h"
#include "HTMLProgressElement.h"
#include "HTMLSlotElement.h"
#include "LoaderStrategy.h"
#include "NodeRenderStyle.h"
#include "Page.h"
#include "PlatformStrategies.h"
#include "RenderElement.h"
#include "RenderView.h"
#include "RuntimeEnabledFeatures.h"
#include "Settings.h"
#include "ShadowRoot.h"
#include "StyleFontSizeFunctions.h"
#include "StyleResolver.h"
#include "StyleScope.h"
#include "Text.h"
namespace WebCore {
namespace Style {
TreeResolver::TreeResolver(Document& document)
: m_document(document)
{
}
TreeResolver::~TreeResolver() = default;
TreeResolver::Scope::Scope(Document& document)
: styleResolver(document.styleScope().resolver())
, sharingResolver(document, styleResolver.ruleSets(), selectorFilter)
{
}
TreeResolver::Scope::Scope(ShadowRoot& shadowRoot, Scope& enclosingScope)
: styleResolver(shadowRoot.styleScope().resolver())
, sharingResolver(shadowRoot.documentScope(), styleResolver.ruleSets(), selectorFilter)
, shadowRoot(&shadowRoot)
, enclosingScope(&enclosingScope)
{
styleResolver.setOverrideDocumentElementStyle(enclosingScope.styleResolver.overrideDocumentElementStyle());
}
TreeResolver::Scope::~Scope()
{
styleResolver.setOverrideDocumentElementStyle(nullptr);
}
TreeResolver::Parent::Parent(Document& document)
: element(nullptr)
, style(*document.renderStyle())
{
}
TreeResolver::Parent::Parent(Element& element, const RenderStyle& style, Change change, DescendantsToResolve descendantsToResolve)
: element(&element)
, style(style)
, change(change)
, descendantsToResolve(descendantsToResolve)
{
}
void TreeResolver::pushScope(ShadowRoot& shadowRoot)
{
m_scopeStack.append(adoptRef(*new Scope(shadowRoot, scope())));
}
void TreeResolver::pushEnclosingScope()
{
ASSERT(scope().enclosingScope);
m_scopeStack.append(*scope().enclosingScope);
}
void TreeResolver::popScope()
{
return m_scopeStack.removeLast();
}
std::unique_ptr<RenderStyle> TreeResolver::styleForElement(Element& element, const RenderStyle& inheritedStyle)
{
if (element.hasCustomStyleResolveCallbacks()) {
RenderStyle* shadowHostStyle = scope().shadowRoot ? m_update->elementStyle(*scope().shadowRoot->host()) : nullptr;
if (auto customStyle = element.resolveCustomStyle(inheritedStyle, shadowHostStyle)) {
if (customStyle->relations)
commitRelations(WTFMove(customStyle->relations), *m_update);
return WTFMove(customStyle->renderStyle);
}
}
if (auto style = scope().sharingResolver.resolve(element, *m_update))
return style;
auto elementStyle = scope().styleResolver.styleForElement(element, &inheritedStyle, parentBoxStyle(), MatchAllRules, &scope().selectorFilter);
if (elementStyle.relations)
commitRelations(WTFMove(elementStyle.relations), *m_update);
return WTFMove(elementStyle.renderStyle);
}
static void resetStyleForNonRenderedDescendants(Element& current)
{
for (auto& child : childrenOfType<Element>(current)) {
if (child.needsStyleRecalc()) {
child.resetComputedStyle();
child.resetStyleRelations();
child.setHasValidStyle();
}
if (child.childNeedsStyleRecalc()) {
resetStyleForNonRenderedDescendants(child);
child.clearChildNeedsStyleRecalc();
}
}
}
static bool affectsRenderedSubtree(Element& element, const RenderStyle& newStyle)
{
if (element.renderer())
return true;
if (newStyle.display() != NONE)
return true;
if (element.rendererIsNeeded(newStyle))
return true;
return false;
}
static const RenderStyle* renderOrDisplayContentsStyle(const Element& element)
{
if (auto* renderStyle = element.renderStyle())
return renderStyle;
if (element.hasDisplayContents())
return element.existingComputedStyle();
return nullptr;
}
static DescendantsToResolve computeDescendantsToResolve(Change change, Validity validity, DescendantsToResolve parentDescendantsToResolve)
{
if (parentDescendantsToResolve == DescendantsToResolve::All)
return DescendantsToResolve::All;
if (validity >= Validity::SubtreeInvalid)
return DescendantsToResolve::All;
switch (change) {
case NoChange:
return DescendantsToResolve::None;
case NoInherit:
return DescendantsToResolve::ChildrenWithExplicitInherit;
case Inherit:
return DescendantsToResolve::Children;
case Detach:
return DescendantsToResolve::All;
};
ASSERT_NOT_REACHED();
return DescendantsToResolve::None;
};
ElementUpdates TreeResolver::resolveElement(Element& element)
{
if (m_didSeePendingStylesheet && !element.renderer() && !m_document.isIgnoringPendingStylesheets()) {
m_document.setHasNodesWithMissingStyle();
return { };
}
auto newStyle = styleForElement(element, parent().style);
if (!affectsRenderedSubtree(element, *newStyle))
return { };
auto* existingStyle = renderOrDisplayContentsStyle(element);
if (m_didSeePendingStylesheet && (!existingStyle || existingStyle->isNotFinal())) {
newStyle->setIsNotFinal();
m_document.setHasNodesWithNonFinalStyle();
}
auto update = createAnimatedElementUpdate(WTFMove(newStyle), element, parent().change);
auto descendantsToResolve = computeDescendantsToResolve(update.change, element.styleValidity(), parent().descendantsToResolve);
if (&element == m_document.documentElement()) {
m_documentElementStyle = RenderStyle::clonePtr(*update.style);
scope().styleResolver.setOverrideDocumentElementStyle(m_documentElementStyle.get());
if (update.change != NoChange && existingStyle && existingStyle->computedFontPixelSize() != update.style->computedFontPixelSize()) {
// "rem" units are relative to the document element's font size so we need to recompute everything.
// In practice this is rare.
scope().styleResolver.invalidateMatchedPropertiesCache();
descendantsToResolve = DescendantsToResolve::All;
}
}
// This is needed for resolving color:-webkit-text for subsequent elements.
// FIXME: We shouldn't mutate document when resolving style.
if (&element == m_document.body())
m_document.setTextColor(update.style->visitedDependentColor(CSSPropertyColor));
// FIXME: These elements should not change renderer based on appearance property.
if (element.hasTagName(HTMLNames::meterTag) || is<HTMLProgressElement>(element)) {
if (existingStyle && update.style->appearance() != existingStyle->appearance()) {
update.change = Detach;
descendantsToResolve = DescendantsToResolve::All;
}
}
auto beforeUpdate = resolvePseudoStyle(element, update, BEFORE);
auto afterUpdate = resolvePseudoStyle(element, update, AFTER);
return { WTFMove(update), descendantsToResolve, WTFMove(beforeUpdate), WTFMove(afterUpdate) };
}
ElementUpdate TreeResolver::resolvePseudoStyle(Element& element, const ElementUpdate& elementUpdate, PseudoId pseudoId)
{
if (elementUpdate.style->display() == NONE)
return { };
if (!elementUpdate.style->hasPseudoStyle(pseudoId))
return { };
auto pseudoStyle = scope().styleResolver.pseudoStyleForElement(element, { pseudoId }, *elementUpdate.style, &scope().selectorFilter);
if (!pseudoStyle)
return { };
PseudoElement* pseudoElement = pseudoId == BEFORE ? element.beforePseudoElement() : element.afterPseudoElement();
if (!pseudoElement) {
auto newPseudoElement = PseudoElement::create(element, pseudoId);
pseudoElement = newPseudoElement.ptr();
if (pseudoId == BEFORE)
element.setBeforePseudoElement(WTFMove(newPseudoElement));
else
element.setAfterPseudoElement(WTFMove(newPseudoElement));
}
return createAnimatedElementUpdate(WTFMove(pseudoStyle), *pseudoElement, elementUpdate.change);
}
const RenderStyle* TreeResolver::parentBoxStyle() const
{
// 'display: contents' doesn't generate boxes.
for (unsigned i = m_parentStack.size(); i; --i) {
auto& parent = m_parentStack[i - 1];
if (parent.style.display() == NONE)
return nullptr;
if (parent.style.display() != CONTENTS)
return &parent.style;
}
ASSERT_NOT_REACHED();
return nullptr;
}
ElementUpdate TreeResolver::createAnimatedElementUpdate(std::unique_ptr<RenderStyle> newStyle, Element& element, Change parentChange)
{
auto* oldStyle = renderOrDisplayContentsStyle(element);
// New code path for CSS Animations and CSS Transitions.
if (RuntimeEnabledFeatures::sharedFeatures().cssAnimationsAndCSSTransitionsBackedByWebAnimationsEnabled()) {
// First, we need to make sure that any new CSS animation occuring on this element has a matching WebAnimation
// on the document timeline. Note that we get timeline() on the Document here because we need a timeline created
// in case no Web Animations have been created through the JS API.
if ((oldStyle && oldStyle->hasTransitions()) || newStyle->hasTransitions())
m_document.timeline().updateCSSTransitionsForElement(element, *newStyle, oldStyle);
if ((oldStyle && oldStyle->hasAnimations()) || newStyle->hasAnimations())
m_document.timeline().updateCSSAnimationsForElement(element, *newStyle, oldStyle);
}
if (auto timeline = m_document.existingTimeline()) {
// Now we can update all Web animations, which will include CSS Animations as well
// as animations created via the JS API.
auto webAnimations = timeline->animationsForElement(element);
if (!webAnimations.isEmpty()) {
auto animatedStyle = RenderStyle::clonePtr(*newStyle);
for (const auto& animation : webAnimations)
animation->resolve(*animatedStyle);
newStyle = WTFMove(animatedStyle);
}
}
bool shouldRecompositeLayer = false;
// Old code path for CSS Animations and CSS Transitions.
if (!RuntimeEnabledFeatures::sharedFeatures().cssAnimationsAndCSSTransitionsBackedByWebAnimationsEnabled()) {
auto& animationController = m_document.frame()->animation();
auto animationUpdate = animationController.updateAnimations(element, *newStyle, oldStyle);
shouldRecompositeLayer = animationUpdate.stateChanged;
if (animationUpdate.style)
newStyle = WTFMove(animationUpdate.style);
}
auto change = oldStyle ? determineChange(*oldStyle, *newStyle) : Detach;
auto validity = element.styleValidity();
if (validity >= Validity::SubtreeAndRenderersInvalid || parentChange == Detach)
change = Detach;
shouldRecompositeLayer |= element.styleResolutionShouldRecompositeLayer();
return { WTFMove(newStyle), change, shouldRecompositeLayer };
}
void TreeResolver::pushParent(Element& element, const RenderStyle& style, Change change, DescendantsToResolve descendantsToResolve)
{
scope().selectorFilter.pushParent(&element);
Parent parent(element, style, change, descendantsToResolve);
if (auto* shadowRoot = element.shadowRoot()) {
pushScope(*shadowRoot);
parent.didPushScope = true;
}
else if (is<HTMLSlotElement>(element) && downcast<HTMLSlotElement>(element).assignedNodes()) {
pushEnclosingScope();
parent.didPushScope = true;
}
m_parentStack.append(WTFMove(parent));
}
void TreeResolver::popParent()
{
auto& parentElement = *parent().element;
parentElement.setHasValidStyle();
parentElement.clearChildNeedsStyleRecalc();
if (parent().didPushScope)
popScope();
scope().selectorFilter.popParent();
m_parentStack.removeLast();
}
void TreeResolver::popParentsToDepth(unsigned depth)
{
ASSERT(depth);
ASSERT(m_parentStack.size() >= depth);
while (m_parentStack.size() > depth)
popParent();
}
static bool shouldResolvePseudoElement(const PseudoElement* pseudoElement)
{
if (!pseudoElement)
return false;
return pseudoElement->needsStyleRecalc();
}
static bool shouldResolveElement(const Element& element, DescendantsToResolve parentDescendantsToResolve)
{
if (element.styleValidity() != Validity::Valid)
return true;
if (shouldResolvePseudoElement(element.beforePseudoElement()))
return true;
if (shouldResolvePseudoElement(element.afterPseudoElement()))
return true;
switch (parentDescendantsToResolve) {
case DescendantsToResolve::None:
return false;
case DescendantsToResolve::Children:
case DescendantsToResolve::All:
return true;
case DescendantsToResolve::ChildrenWithExplicitInherit:
auto* existingStyle = renderOrDisplayContentsStyle(element);
return existingStyle && existingStyle->hasExplicitlyInheritedProperties();
};
ASSERT_NOT_REACHED();
return false;
}
static void clearNeedsStyleResolution(Element& element)
{
element.setHasValidStyle();
if (auto* before = element.beforePseudoElement())
before->setHasValidStyle();
if (auto* after = element.afterPseudoElement())
after->setHasValidStyle();
}
static bool hasLoadingStylesheet(const Style::Scope& styleScope, const Element& element, bool checkDescendants)
{
if (!styleScope.hasPendingSheetsInBody())
return false;
if (styleScope.hasPendingSheetInBody(element))
return true;
if (!checkDescendants)
return false;
for (auto& descendant : descendantsOfType<Element>(element)) {
if (styleScope.hasPendingSheetInBody(descendant))
return true;
};
return false;
}
static std::unique_ptr<RenderStyle> createInheritedDisplayContentsStyleIfNeeded(const RenderStyle& parentElementStyle, const RenderStyle* parentBoxStyle)
{
if (parentElementStyle.display() != CONTENTS)
return nullptr;
if (parentBoxStyle && !parentBoxStyle->inheritedNotEqual(&parentElementStyle))
return nullptr;
// Compute style for imaginary unstyled <span> around the text node.
auto style = RenderStyle::createPtr();
style->inheritFrom(parentElementStyle);
return style;
}
void TreeResolver::resolveComposedTree()
{
ASSERT(m_parentStack.size() == 1);
ASSERT(m_scopeStack.size() == 1);
auto descendants = composedTreeDescendants(m_document);
auto it = descendants.begin();
auto end = descendants.end();
while (it != end) {
popParentsToDepth(it.depth());
auto& node = *it;
auto& parent = this->parent();
ASSERT(node.isConnected());
ASSERT(node.containingShadowRoot() == scope().shadowRoot);
ASSERT(node.parentElement() == parent.element || is<ShadowRoot>(node.parentNode()) || node.parentElement()->shadowRoot());
if (is<Text>(node)) {
auto& text = downcast<Text>(node);
if ((text.styleValidity() >= Validity::SubtreeAndRenderersInvalid && parent.change != Detach) || parent.style.display() == CONTENTS) {
TextUpdate textUpdate;
textUpdate.inheritedDisplayContentsStyle = createInheritedDisplayContentsStyleIfNeeded(parent.style, parentBoxStyle());
m_update->addText(text, parent.element, WTFMove(textUpdate));
}
text.setHasValidStyle();
it.traverseNextSkippingChildren();
continue;
}
auto& element = downcast<Element>(node);
if (it.depth() > Settings::defaultMaximumRenderTreeDepth) {
resetStyleForNonRenderedDescendants(element);
element.clearChildNeedsStyleRecalc();
it.traverseNextSkippingChildren();
continue;
}
auto* style = renderOrDisplayContentsStyle(element);
auto change = NoChange;
auto descendantsToResolve = DescendantsToResolve::None;
bool shouldResolve = shouldResolveElement(element, parent.descendantsToResolve);
if (shouldResolve) {
if (!element.hasDisplayContents())
element.resetComputedStyle();
element.resetStyleRelations();
if (element.hasCustomStyleResolveCallbacks())
element.willRecalcStyle(parent.change);
auto elementUpdates = resolveElement(element);
if (element.hasCustomStyleResolveCallbacks())
element.didRecalcStyle(elementUpdates.update.change);
style = elementUpdates.update.style.get();
change = elementUpdates.update.change;
descendantsToResolve = elementUpdates.descendantsToResolve;
if (elementUpdates.update.style)
m_update->addElement(element, parent.element, WTFMove(elementUpdates));
clearNeedsStyleResolution(element);
}
if (!style) {
resetStyleForNonRenderedDescendants(element);
element.clearChildNeedsStyleRecalc();
}
bool shouldIterateChildren = style && (element.childNeedsStyleRecalc() || descendantsToResolve != DescendantsToResolve::None);
if (!m_didSeePendingStylesheet)
m_didSeePendingStylesheet = hasLoadingStylesheet(m_document.styleScope(), element, !shouldIterateChildren);
if (!shouldIterateChildren) {
it.traverseNextSkippingChildren();
continue;
}
pushParent(element, *style, change, descendantsToResolve);
it.traverseNext();
}
popParentsToDepth(1);
}
std::unique_ptr<Update> TreeResolver::resolve()
{
auto& renderView = *m_document.renderView();
Element* documentElement = m_document.documentElement();
if (!documentElement) {
m_document.styleScope().resolver();
return nullptr;
}
if (!documentElement->childNeedsStyleRecalc() && !documentElement->needsStyleRecalc())
return nullptr;
m_didSeePendingStylesheet = m_document.styleScope().hasPendingSheetsBeforeBody();
m_update = std::make_unique<Update>(m_document);
m_scopeStack.append(adoptRef(*new Scope(m_document)));
m_parentStack.append(Parent(m_document));
// Pseudo element removal and similar may only work with these flags still set. Reset them after the style recalc.
renderView.setUsesFirstLineRules(renderView.usesFirstLineRules() || scope().styleResolver.usesFirstLineRules());
renderView.setUsesFirstLetterRules(renderView.usesFirstLetterRules() || scope().styleResolver.usesFirstLetterRules());
resolveComposedTree();
renderView.setUsesFirstLineRules(scope().styleResolver.usesFirstLineRules());
renderView.setUsesFirstLetterRules(scope().styleResolver.usesFirstLetterRules());
ASSERT(m_scopeStack.size() == 1);
ASSERT(m_parentStack.size() == 1);
m_parentStack.clear();
popScope();
if (m_update->roots().isEmpty())
return { };
return WTFMove(m_update);
}
static Vector<Function<void ()>>& postResolutionCallbackQueue()
{
static NeverDestroyed<Vector<Function<void ()>>> vector;
return vector;
}
void queuePostResolutionCallback(Function<void ()>&& callback)
{
postResolutionCallbackQueue().append(WTFMove(callback));
}
static void suspendMemoryCacheClientCalls(Document& document)
{
Page* page = document.page();
if (!page || !page->areMemoryCacheClientCallsEnabled())
return;
page->setMemoryCacheClientCallsEnabled(false);
postResolutionCallbackQueue().append([protectedMainFrame = makeRef(page->mainFrame())] {
if (Page* page = protectedMainFrame->page())
page->setMemoryCacheClientCallsEnabled(true);
});
}
static unsigned resolutionNestingDepth;
PostResolutionCallbackDisabler::PostResolutionCallbackDisabler(Document& document)
{
++resolutionNestingDepth;
if (resolutionNestingDepth == 1)
platformStrategies()->loaderStrategy()->suspendPendingRequests();
// FIXME: It's strange to build this into the disabler.
suspendMemoryCacheClientCalls(document);
}
PostResolutionCallbackDisabler::~PostResolutionCallbackDisabler()
{
if (resolutionNestingDepth == 1) {
// Get size each time through the loop because a callback can add more callbacks to the end of the queue.
auto& queue = postResolutionCallbackQueue();
for (size_t i = 0; i < queue.size(); ++i)
queue[i]();
queue.clear();
platformStrategies()->loaderStrategy()->resumePendingRequests();
}
--resolutionNestingDepth;
}
bool postResolutionCallbacksAreSuspended()
{
return resolutionNestingDepth;
}
}
}