LibWeb: Add definitions from '2.1. URL' in the Fetch spec

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -118,6 +118,7 @@ set(SOURCES
     Encoding/TextDecoder.cpp
     Encoding/TextEncoder.cpp
     Fetch/AbstractOperations.cpp
+    Fetch/Infrastructure/URL.cpp
     FontCache.cpp
     Geometry/DOMRectList.cpp
     HTML/AttributeNames.cpp

Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.cpp

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Fetch/Infrastructure/URL.h>
+
+namespace Web::Fetch {
+
+// https://fetch.spec.whatwg.org/#is-local
+bool is_local_url(AK::URL const& url)
+{
+    // A URL is local if its scheme is a local scheme.
+    return any_of(LOCAL_SCHEMES, [&](auto scheme) { return url.scheme() == scheme; });
+}
+
+}

Userland/Libraries/LibWeb/Fetch/Infrastructure/URL.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2022, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Array.h>
+#include <AK/URL.h>
+
+namespace Web::Fetch {
+
+// https://fetch.spec.whatwg.org/#local-scheme
+// A local scheme is "about", "blob", or "data".
+inline constexpr Array LOCAL_SCHEMES = {
+    "about"sv, "blob"sv, "data"sv
+};
+
+// https://fetch.spec.whatwg.org/#http-scheme
+// An HTTP(S) scheme is "http" or "https".
+inline constexpr Array HTTP_SCHEMES = {
+    "http"sv, "https"sv
+};
+
+// https://fetch.spec.whatwg.org/#fetch-scheme
+// A fetch scheme is "about", "blob", "data", "file", or an HTTP(S) scheme.
+inline constexpr Array FETCH_SCHEMES = {
+    "about"sv, "blob"sv, "data"sv, "file"sv, "http"sv, "https"sv
+};
+
+[[nodiscard]] bool is_local_url(AK::URL const&);
+
+}