Refactor "had element child" determination logic in ContainerNode::re…

…moveAllChildrenWithScriptAssertion

https://bugs.webkit.org/show_bug.cgi?id=244732
rdar://99506128

Reviewed by Chris Dumez.

* Source/WebCore/dom/ContainerNode.cpp:
(WebCore::ContainerNode::removeAllChildrenWithScriptAssertion):

Refactor logic to compute `hadElementChild` in a single place.

* Source/WebCore/dom/ContainerNode.h:

Introduce an `Unknown` value, as `ChildChange` is passed into
`ChildChangeInvalidation` prior to the `hadElementChild` computation. While
the value of `affectsElements` is not read in `ChildChangeInvalidation`,
use the `Unknown` value to make the current behavior explicit.

* Source/WebCore/html/HTMLSelectElement.cpp:
(WebCore::HTMLSelectElement::childrenChanged):

Canonical link: https://commits.webkit.org/254331@main

Source/WebCore/dom/ContainerNode.cpp

@@ -99,11 +99,9 @@ ALWAYS_INLINE auto ContainerNode::removeAllChildrenWithScriptAssertion(ChildChan
         return hadElementChild ? DidRemoveElements::Yes : DidRemoveElements::No;
     }
 
-    bool hadElementChild = false;
     if (source == ChildChange::Source::API) {
         ChildListMutationScope mutation(*this);
         for (auto& child : children) {
-            hadElementChild |= is<Element>(child);
             mutation.willRemoveChild(child.get());
             child->notifyMutationObserversNodeWillDetach();
             dispatchChildRemovalEvents(child);
@@ -113,17 +111,16 @@ ALWAYS_INLINE auto ContainerNode::removeAllChildrenWithScriptAssertion(ChildChan
         ScriptDisallowedScope::InMainThread scriptDisallowedScope;
         if (UNLIKELY(document().hasMutationObserversOfType(MutationObserverOptionType::ChildList))) {
             ChildListMutationScope mutation(*this);
-            for (auto& child : children) {
-                hadElementChild |= is<Element>(child);
+            for (auto& child : children)
                 mutation.willRemoveChild(child.get());
-            }
-        } else
-            hadElementChild = children.containsIf([](auto& child) { return is<Element>(child); });
+        }
     }
 
     disconnectSubframesIfNeeded(*this, DescendantsOnly);
 
-    ContainerNode::ChildChange childChange { ChildChange::Type::AllChildrenRemoved, nullptr, nullptr, nullptr, source, hadElementChild ? ContainerNode::ChildChange::AffectsElements::Yes : ContainerNode::ChildChange::AffectsElements::No };
+    ContainerNode::ChildChange childChange { ChildChange::Type::AllChildrenRemoved, nullptr, nullptr, nullptr, source, ContainerNode::ChildChange::AffectsElements::Unknown };
+
+    bool hadElementChild = false;
 
     WidgetHierarchyUpdatesSuspensionScope suspendWidgetHierarchyUpdates;
     ScriptDisallowedScope::InMainThread scriptDisallowedScope;
@@ -136,11 +133,16 @@ ALWAYS_INLINE auto ContainerNode::removeAllChildrenWithScriptAssertion(ChildChan
         document().nodeChildrenWillBeRemoved(*this);
 
         while (RefPtr<Node> child = m_firstChild) {
+            if (is<Element>(*child))
+                hadElementChild = true;
+
             removeBetween(nullptr, child->nextSibling(), *child);
             auto subtreeObservability = notifyChildNodeRemoved(*this, *child);
             if (source == ChildChange::Source::API && subtreeObservability == RemovedSubtreeObservability::MaybeObservableByRefPtr)
                 willCreatePossiblyOrphanedTreeByRemoval(*child);
         }
+
+        childChange.affectsElements = hadElementChild ? ContainerNode::ChildChange::AffectsElements::Yes : ContainerNode::ChildChange::AffectsElements::No;
     }
 
     ASSERT_WITH_SECURITY_IMPLICATION(!document().selection().selection().isOrphan());

Source/WebCore/dom/ContainerNode.h

@@ -78,7 +78,7 @@ class ContainerNode : public Node {
     struct ChildChange {
         enum class Type : uint8_t { ElementInserted, ElementRemoved, TextInserted, TextRemoved, TextChanged, AllChildrenRemoved, NonContentsChildRemoved, NonContentsChildInserted, AllChildrenReplaced };
         enum class Source : bool { Parser, API };
-        enum class AffectsElements : bool { No, Yes };
+        enum class AffectsElements : uint8_t { Unknown, No, Yes };
 
         ChildChange::Type type;
         Element* siblingChanged;

Source/WebCore/html/HTMLSelectElement.cpp

@@ -404,6 +404,8 @@ CompletionHandlerCallingScope HTMLSelectElement::optionToSelectFromChildChangeSc
 
 void HTMLSelectElement::childrenChanged(const ChildChange& change)
 {
+    ASSERT(change.affectsElements != ChildChange::AffectsElements::Unknown);
+
     if (change.affectsElements == ChildChange::AffectsElements::No) {
         HTMLFormControlElementWithState::childrenChanged(change);
         return;