Avoid ElementIdentifier-related work under Element::removedFromAncest…

…or()

https://bugs.webkit.org/show_bug.cgi?id=240932

Reviewed by Darin Adler.

Avoid ElementIdentifier-related work under Element::removedFromAncestor() since it is a
hot function and we want to do as little work as possible in there.

* Source/WebCore/dom/Document.cpp:
(WebCore::Document::dispatchSystemPreviewActionEvent):
(WebCore::Document::identifierForElement): Deleted.
(WebCore::Document::searchForElementByIdentifier): Deleted.
(WebCore::Document::identifiedElementWasRemovedFromDocument): Deleted.
* Source/WebCore/dom/Document.h:
* Source/WebCore/dom/Element.cpp:
(WebCore::Element::removedFromAncestor):
(WebCore::elementIdentifiersMap):
(WebCore::Element::identifier const):
(WebCore::Element::fromIdentifier):
(WebCore::Element::createElementIdentifier): Deleted.
* Source/WebCore/dom/Element.h:
* Source/WebCore/dom/Node.h:
* Source/WebCore/html/HTMLAnchorElement.cpp:
(WebCore::HTMLAnchorElement::handleClick):
* Source/WebCore/page/InteractionRegion.cpp:
(WebCore::regionForElement):
* Source/WebCore/testing/Internals.cpp:
(WebCore::Internals::elementIdentifier const):
(WebCore::Internals::isElementAlive const):
* Source/WebKit/WebProcess/WebPage/WebPage.cpp:
(WebKit::WebPage::elementForContext const):
(WebKit::WebPage::contextForElement const):
* Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm:
(WebKit::WebPage::textInputContextsInRect):

Canonical link: https://commits.webkit.org/251042@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@294931 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebCore/dom/Document.cpp

@@ -8906,30 +8906,6 @@ bool Document::hitTest(const HitTestRequest& request, const HitTestLocation& loc
     return resultLayer;
 }
 
-ElementIdentifier Document::identifierForElement(Element& element)
-{
-    ASSERT(&element.document() == this);
-    auto result = m_identifiedElementsMap.ensure(&element, [&] {
-        return element.createElementIdentifier();
-    });
-    return result.iterator->value;
-}
-
-Element* Document::searchForElementByIdentifier(const ElementIdentifier& identifier)
-{
-    for (auto it = m_identifiedElementsMap.begin(); it != m_identifiedElementsMap.end(); ++it) {
-        if (it->value == identifier)
-            return it->key;
-    }
-
-    return nullptr;
-}
-
-void Document::identifiedElementWasRemovedFromDocument(Element& element)
-{
-    m_identifiedElementsMap.remove(&element);
-}
-
 #if ENABLE(DEVICE_ORIENTATION)
 
 DeviceOrientationAndMotionAccessController& Document::deviceOrientationAndMotionAccessController()
@@ -9024,11 +9000,11 @@ MessagePortChannelProvider& Document::messagePortChannelProvider()
 #if USE(SYSTEM_PREVIEW)
 void Document::dispatchSystemPreviewActionEvent(const SystemPreviewInfo& systemPreviewInfo, const String& message)
 {
-    RefPtr element = searchForElementByIdentifier(systemPreviewInfo.element.elementIdentifier);
-    if (!element)
+    RefPtr element = Element::fromIdentifier(systemPreviewInfo.element.elementIdentifier);
+    if (!is<HTMLAnchorElement>(element))
         return;
 
-    if (!is<HTMLAnchorElement>(element))
+    if (!element->isConnected() || &element->document() != this)
         return;
 
     auto event = MessageEvent::create(message, securityOrigin().toString());

Source/WebCore/dom/Document.h

@@ -35,7 +35,6 @@
 #include "CrossOriginOpenerPolicy.h"
 #include "DisabledAdaptations.h"
 #include "DocumentEventTiming.h"
-#include "ElementIdentifier.h"
 #include "FocusOptions.h"
 #include "FontSelectorClient.h"
 #include "FrameDestructionObserver.h"
@@ -392,10 +391,6 @@ class Document
     WEBCORE_EXPORT static DocumentsMap::ValuesIteratorRange allDocuments();
     WEBCORE_EXPORT static DocumentsMap& allDocumentsMap();
 
-    WEBCORE_EXPORT ElementIdentifier identifierForElement(Element&);
-    WEBCORE_EXPORT Element* searchForElementByIdentifier(const ElementIdentifier&);
-    void identifiedElementWasRemovedFromDocument(Element&);
-
     MediaQueryMatcher& mediaQueryMatcher();
 
     using ContainerNode::ref;
@@ -2263,8 +2258,6 @@ class Document
 
     std::unique_ptr<TextManipulationController> m_textManipulationController;
 
-    HashMap<Element*, ElementIdentifier> m_identifiedElementsMap;
-
     UniqueRef<Editor> m_editor;
     UniqueRef<FrameSelection> m_selection;
 

Source/WebCore/dom/Element.cpp

@@ -2548,11 +2548,6 @@ void Element::removedFromAncestor(RemovalType removalType, ContainerNode& oldPar
 
     if (UNLIKELY(isInTopLayer()))
         removeFromTopLayer();
-
-    if (hasNodeFlag(NodeFlag::HasElementIdentifier)) {
-        document().identifiedElementWasRemovedFromDocument(*this);
-        clearNodeFlag(NodeFlag::HasElementIdentifier);
-    }
 }
 
 void Element::addShadowRoot(Ref<ShadowRoot>&& newShadowRoot)
@@ -4866,11 +4861,24 @@ Vector<RefPtr<WebAnimation>> Element::getAnimations(std::optional<GetAnimationsO
     return animations;
 }
 
-ElementIdentifier Element::createElementIdentifier()
+static WeakHashMap<Element, ElementIdentifier>& elementIdentifiersMap()
+{
+    static MainThreadNeverDestroyed<WeakHashMap<Element, ElementIdentifier>> map;
+    return map;
+}
+
+ElementIdentifier Element::identifier() const
 {
-    ASSERT(!hasNodeFlag(NodeFlag::HasElementIdentifier));
-    setNodeFlag(NodeFlag::HasElementIdentifier);
-    return ElementIdentifier::generate();
+    return elementIdentifiersMap().ensure(*this, [] { return ElementIdentifier::generate(); }).iterator->value;
+}
+
+Element* Element::fromIdentifier(ElementIdentifier identifier)
+{
+    for (auto [element, elementIdentifier] : elementIdentifiersMap()) {
+        if (elementIdentifier == identifier)
+            return &element;
+    }
+    return nullptr;
 }
 
 #if ENABLE(CSS_TYPED_OM)

Source/WebCore/dom/Element.h

@@ -660,7 +660,8 @@ class Element : public ContainerNode {
     ExceptionOr<Ref<WebAnimation>> animate(JSC::JSGlobalObject&, JSC::Strong<JSC::JSObject>&&, std::optional<std::variant<double, KeyframeAnimationOptions>>&&);
     Vector<RefPtr<WebAnimation>> getAnimations(std::optional<GetAnimationsOptions>);
 
-    ElementIdentifier createElementIdentifier();
+    WEBCORE_EXPORT ElementIdentifier identifier() const;
+    WEBCORE_EXPORT static Element* fromIdentifier(ElementIdentifier);
 
     String description() const override;
     String debugDescription() const override;

Source/WebCore/dom/Node.h

@@ -565,7 +565,7 @@ class Node : public EventTarget {
         HasCustomStyleResolveCallbacks = 1 << 21,
 
         HasPendingResources = 1 << 22,
-        HasElementIdentifier = 1 << 23,
+        // Bit 23 is free.
 #if ENABLE(FULLSCREEN_API)
         ContainsFullScreenElement = 1 << 24,
 #endif

Source/WebCore/html/HTMLAnchorElement.cpp

@@ -593,7 +593,7 @@ void HTMLAnchorElement::handleClick(Event& event)
     systemPreviewInfo.isPreview = isSystemPreviewLink() && document().settings().systemPreviewEnabled();
 
     if (systemPreviewInfo.isPreview) {
-        systemPreviewInfo.element.elementIdentifier = document().identifierForElement(*this);
+        systemPreviewInfo.element.elementIdentifier = identifier();
         systemPreviewInfo.element.documentIdentifier = document().identifier();
         systemPreviewInfo.element.webPageIdentifier = valueOrDefault(document().frame()->loader().pageID());
         if (auto* child = firstElementChild())

Source/WebCore/page/InteractionRegion.cpp

@@ -77,7 +77,7 @@ static std::optional<InteractionRegion> regionForElement(Element& element)
     Vector<FloatRect> rectsInContentCoordinates;
     InteractionRegion region;
 
-    region.elementIdentifier = document->identifierForElement(element);
+    region.elementIdentifier = element.identifier();
 
     auto linkRange = makeRangeSelectingNode(element);
     if (linkRange)

Source/WebCore/testing/Internals.cpp

@@ -2791,12 +2791,12 @@ uint64_t Internals::storageAreaMapCount() const
 
 uint64_t Internals::elementIdentifier(Element& element) const
 {
-    return element.document().identifierForElement(element).toUInt64();
+    return element.identifier().toUInt64();
 }
 
-bool Internals::isElementAlive(Document& document, uint64_t elementIdentifier) const
+bool Internals::isElementAlive(uint64_t elementIdentifier) const
 {
-    return document.searchForElementByIdentifier(makeObjectIdentifier<ElementIdentifierType>(elementIdentifier));
+    return Element::fromIdentifier(makeObjectIdentifier<ElementIdentifierType>(elementIdentifier));
 }
 
 uint64_t Internals::frameIdentifier(const Document& document) const

Source/WebCore/testing/Internals.h

@@ -513,7 +513,7 @@ class Internals final : public RefCounted<Internals>, private ContextDestruction
     uint64_t storageAreaMapCount() const;
 
     uint64_t elementIdentifier(Element&) const;
-    bool isElementAlive(Document&, uint64_t documentIdentifier) const;
+    bool isElementAlive(uint64_t elementIdentifier) const;
 
     uint64_t frameIdentifier(const Document&) const;
     uint64_t pageIdentifier(const Document&) const;

Source/WebCore/testing/Internals.idl

@@ -958,7 +958,7 @@ typedef (FetchRequest or FetchResponse) FetchObject;
     readonly attribute unsigned long long storageAreaMapCount;
 
     unsigned long long elementIdentifier(Element element);
-    [CallWith=CurrentDocument] boolean isElementAlive(unsigned long long documentIdentifier);
+    boolean isElementAlive(unsigned long long elementIdentifier);
     unsigned long long frameIdentifier(Document document);
     unsigned long long pageIdentifier(Document document);
 

Source/WebKit/WebProcess/WebPage/WebPage.cpp

@@ -7553,14 +7553,14 @@ RefPtr<Element> WebPage::elementForContext(const ElementContext& elementContext)
     if (elementContext.webPageIdentifier != m_identifier)
         return nullptr;
 
-    auto* document = Document::allDocumentsMap().get(elementContext.documentIdentifier);
-    if (!document)
+    RefPtr element = Element::fromIdentifier(elementContext.elementIdentifier);
+    if (!element)
         return nullptr;
 
-    if (document->page() != m_page.get())
+    if (!element->isConnected() || element->document().identifier() != elementContext.documentIdentifier || element->document().page() != m_page.get())
         return nullptr;
 
-    return document->searchForElementByIdentifier(elementContext.elementIdentifier);
+    return element;
 }
 
 std::optional<WebCore::ElementContext> WebPage::contextForElement(WebCore::Element& element) const
@@ -7573,7 +7573,7 @@ std::optional<WebCore::ElementContext> WebPage::contextForElement(WebCore::Eleme
     if (!frame)
         return std::nullopt;
 
-    return WebCore::ElementContext { element.boundingBoxInRootViewCoordinates(), m_identifier, document.identifier(), document.identifierForElement(element) };
+    return WebCore::ElementContext { element.boundingBoxInRootViewCoordinates(), m_identifier, document.identifier(), element.identifier() };
 }
 
 void WebPage::startTextManipulations(Vector<WebCore::TextManipulationController::ExclusionRule>&& exclusionRules, CompletionHandler<void()>&& completionHandler)

Source/WebKit/WebProcess/WebPage/ios/WebPageIOS.mm

@@ -4754,7 +4754,7 @@ static VisiblePositionRange constrainRangeToSelection(const VisiblePositionRange
         ElementContext context;
         context.webPageIdentifier = m_identifier;
         context.documentIdentifier = document.identifier();
-        context.elementIdentifier = document.identifierForElement(element);
+        context.elementIdentifier = element->identifier();
         context.boundingRect = element->boundingBoxInRootViewCoordinates();
         return context;
     });