LibWeb: Implement 'Strip url for use as a referrer' AO

Userland/Libraries/LibWeb/ReferrerPolicy/AbstractOperations.cpp

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/URL.h>
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/Fetch/Infrastructure/URL.h>
+#include <LibWeb/ReferrerPolicy/AbstractOperations.h>
+#include <LibWeb/URL/URL.h>
+
+namespace Web::ReferrerPolicy {
+
+Optional<AK::URL> strip_url_for_use_as_referrer(Optional<AK::URL> url, OriginOnly origin_only)
+{
+    // 1. If url is null, return no referrer.
+    if (!url.has_value())
+        return {};
+
+    // 2. If url’s scheme is a local scheme, then return no referrer.
+    if (Fetch::Infrastructure::LOCAL_SCHEMES.span().contains_slow(url->scheme()))
+        return {};
+
+    // 3. Set url’s username to the empty string.
+    url->set_username(""sv);
+
+    // 4. Set url’s password to the empty string.
+    url->set_password(""sv);
+
+    // 5. Set url’s fragment to null.
+    url->set_fragment({});
+
+    // 6. If the origin-only flag is true, then:
+    if (origin_only == OriginOnly::Yes) {
+        // 1. Set url’s path to « the empty string ».
+        url->set_paths({ ""sv });
+
+        // 2. Set url’s query to null.
+        url->set_query({});
+    }
+
+    // 7. Return url.
+    return url;
+}
+
+}