LibWeb/HTML: Implement TextTrackCueList idl interface

Author: https://github.com/jamierocks
Commit: cfec88feb3
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1494
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/tcl3 ✅

Userland/Libraries/LibWeb/HTML/TextTrackCueList.cpp

@@ -0,0 +1,79 @@
+/*
+ * Copyright (c) 2024, Jamie Mansfield <jmansfield@cadixdev.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/Runtime/Realm.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/Bindings/TextTrackCueListPrototype.h>
+#include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/HTML/TextTrackCueList.h>
+
+namespace Web::HTML {
+
+JS_DEFINE_ALLOCATOR(TextTrackCueList);
+
+TextTrackCueList::TextTrackCueList(JS::Realm& realm)
+    : DOM::EventTarget(realm, MayInterfereWithIndexedPropertyAccess::Yes)
+{
+}
+
+TextTrackCueList::~TextTrackCueList() = default;
+
+void TextTrackCueList::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(TextTrackCueList);
+}
+
+void TextTrackCueList::visit_edges(JS::Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_cues);
+}
+
+// https://html.spec.whatwg.org/multipage/media.html#dom-texttrackcuelist-item
+JS::ThrowCompletionOr<Optional<JS::PropertyDescriptor>> TextTrackCueList::internal_get_own_property(JS::PropertyKey const& property_name) const
+{
+    // To determine the value of an indexed property for a given index index, the user agent must return the indexth text track cue in the list
+    // represented by the TextTrackCueList object.
+    if (property_name.is_number()) {
+        if (auto index = property_name.as_number(); index < m_cues.size()) {
+            JS::PropertyDescriptor descriptor;
+            descriptor.value = m_cues.at(index);
+
+            return descriptor;
+        }
+    }
+
+    return Base::internal_get_own_property(property_name);
+}
+
+// https://html.spec.whatwg.org/multipage/media.html#dom-texttrackcuelist-length
+size_t TextTrackCueList::length() const
+{
+    // The length attribute must return the number of cues in the list represented by the TextTrackCueList object.
+    return m_cues.size();
+}
+
+// https://html.spec.whatwg.org/multipage/media.html#dom-texttrackcuelist-getcuebyid
+JS::GCPtr<TextTrackCue> TextTrackCueList::get_cue_by_id(StringView id) const
+{
+    // The getCueById(id) method, when called with an argument other than the empty string, must return the first text track cue in the list
+    // represented by the TextTrackCueList object whose text track cue identifier is id, if any, or null otherwise. If the argument is the
+    // empty string, then the method must return null.
+    if (id.is_empty())
+        return nullptr;
+
+    auto it = m_cues.find_if([&](auto const& cue) {
+        return cue->id() == id;
+    });
+
+    if (it == m_cues.end())
+        return nullptr;
+
+    return *it;
+}
+
+}