LibWeb: Add `Navigable::set_ongoing_navigation()`

Userland/Libraries/LibWeb/HTML/Navigable.cpp

@@ -260,6 +260,19 @@ JS::GCPtr<TraversableNavigable> Navigable::top_level_traversable()
     return verify_cast<TraversableNavigable>(navigable);
 }
 
+// https://html.spec.whatwg.org/multipage/browsing-the-web.html#set-the-ongoing-navigation
+void Navigable::set_ongoing_navigation(Variant<Empty, Traversal, String> ongoing_navigation)
+{
+    // 1. If navigable's ongoing navigation is equal to newValue, then return.
+    if (m_ongoing_navigation == ongoing_navigation)
+        return;
+
+    // FIXME: 2. Inform the navigation API about aborting navigation given navigable.
+
+    // 3. Set navigable's ongoing navigation to newValue.
+    m_ongoing_navigation = ongoing_navigation;
+}
+
 Navigable::ChosenNavigable Navigable::choose_a_navigable(StringView name, TokenizedFeature::NoOpener, ActivateTab)
 {
     // 1. Let chosen be null.
@@ -919,7 +932,7 @@ WebIDL::ExceptionOr<void> Navigable::navigate(
     }
 
     // 17. Set navigable's ongoing navigation to navigationId.
-    m_ongoing_navigation = navigation_id;
+    set_ongoing_navigation(navigation_id);
 
     // 18. If url's scheme is "javascript", then:
     if (url.scheme() == "javascript"sv) {

Userland/Libraries/LibWeb/HTML/Navigable.h

@@ -105,6 +105,7 @@ public:
     };
 
     Variant<Empty, Traversal, String> ongoing_navigation() const { return m_ongoing_navigation; }
+    void set_ongoing_navigation(Variant<Empty, Traversal, String> ongoing_navigation);
 
     WebIDL::ExceptionOr<void> populate_session_history_entry_document(JS::GCPtr<SessionHistoryEntry>, Optional<NavigationParams>, Optional<String> navigation_id, SourceSnapshotParams const&, bool allow_POST, Function<void()>);
 

Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp

@@ -256,7 +256,7 @@ void TraversableNavigable::apply_the_history_step(int step, Optional<SourceSnaps
         navigable->set_current_session_history_entry(target_entry);
 
         // 3. Set navigable's ongoing navigation to "traversal".
-        m_ongoing_navigation = Traversal::Tag;
+        set_ongoing_navigation(Traversal::Tag);
     }
 
     // 9. Let totalChangeJobs be the size of changingNavigables.
@@ -390,7 +390,7 @@ void TraversableNavigable::apply_the_history_step(int step, Optional<SourceSnaps
         auto navigable = changing_navigable_continuation.navigable;
 
         // 7. Set navigable's ongoing navigation to null.
-        m_ongoing_navigation = {};
+        set_ongoing_navigation({});
 
         // 8. Let (scriptHistoryLength, scriptHistoryIndex) be the result of getting the history object length and index given traversable and targetStep.
         auto [script_history_length, script_history_index] = get_the_history_object_length_and_index(target_step);