LibWeb: Implement StorageKey and related AOs from Storage specification

Author: https://github.com/ADKaster
Commit: f0270b92f1
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1404
Reviewed-by: https://github.com/tcl3 ✅

Userland/Libraries/LibWeb/StorageAPI/StorageKey.cpp

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2024, Andrew Kaster <andrew@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/DOMURL/DOMURL.h>
+#include <LibWeb/HTML/Scripting/Environments.h>
+#include <LibWeb/StorageAPI/StorageKey.h>
+
+namespace Web::StorageAPI {
+
+// https://storage.spec.whatwg.org/#obtain-a-storage-key
+Optional<StorageKey> obtain_a_storage_key(HTML::Environment const& environment)
+{
+    // 1. Let key be the result of running obtain a storage key for non-storage purposes with environment.
+    auto key = obtain_a_storage_key_for_non_storage_purposes(environment);
+
+    // 2. If key’s origin is an opaque origin, then return failure.
+    if (key.origin.is_opaque())
+        return {};
+
+    // FIXME: 3. If the user has disabled storage, then return failure.
+
+    // 4. Return key.
+    return key;
+}
+
+// https://storage.spec.whatwg.org/#obtain-a-storage-key-for-non-storage-purposes
+StorageKey obtain_a_storage_key_for_non_storage_purposes(HTML::Environment const& environment)
+{
+    // 1. Let origin be environment’s origin if environment is an environment settings object; otherwise environment’s creation URL’s origin.
+    if (is<HTML::EnvironmentSettingsObject>(environment)) {
+        auto const& settings = static_cast<HTML::EnvironmentSettingsObject const&>(environment);
+        // FIXME: EnvironmentSettingsObject::origin() should be const :|
+        auto& mutable_settings = const_cast<HTML::EnvironmentSettingsObject&>(settings);
+        return { mutable_settings.origin() };
+    }
+    return { DOMURL::url_origin(environment.creation_url) };
+}
+
+}