LibWeb: Update URL constructor steps to match the specification

This patch adds the API URL parser used by the URL constructor. This
makes the URL constructor steps match the spec again.

Userland/Libraries/LibWeb/URL/URL.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
  * Copyright (c) 2021, the SerenityOS developers.
+ * Copyright (c) 2023, networkException <networkexception@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -18,37 +19,55 @@ WebIDL::ExceptionOr<JS::NonnullGCPtr<URL>> URL::create(JS::Realm& realm, AK::URL
     return MUST_OR_THROW_OOM(realm.heap().allocate<URL>(realm, realm, move(url), move(query)));
 }
 
-WebIDL::ExceptionOr<JS::NonnullGCPtr<URL>> URL::construct_impl(JS::Realm& realm, String const& url, Optional<String> const& base)
+// https://url.spec.whatwg.org/#api-url-parser
+static Optional<AK::URL> parse_api_url(String const& url, Optional<String> const& base)
 {
-    auto& vm = realm.vm();
+    // FIXME: We somewhat awkwardly have two failure states encapsulated in the return type (and convert between them in the steps),
+    //        ideally we'd get rid of URL's valid flag
 
     // 1. Let parsedBase be null.
     Optional<AK::URL> parsed_base;
-    // 2. If base is given, then:
+
+    // 2. If base is non-null:
     if (base.has_value()) {
-        // 1. Let parsedBase be the result of running the basic URL parser on base.
-        parsed_base = base.value();
-        // 2. If parsedBase is failure, then throw a TypeError.
-        if (!parsed_base->is_valid())
-            return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Invalid base URL"sv };
+        // 1. Set parsedBase to the result of running the basic URL parser on base.
+        auto parsed_base_url = URLParser::parse(*base);
+
+        // 2. If parsedBase is failure, then return failure.
+        if (!parsed_base_url.is_valid())
+            return {};
+
+        parsed_base = parsed_base_url;
     }
-    // 3. Let parsedURL be the result of running the basic URL parser on url with parsedBase.
-    AK::URL parsed_url;
-    if (parsed_base.has_value())
-        parsed_url = parsed_base->complete_url(url);
-    else
-        parsed_url = url;
-    // 4. If parsedURL is failure, then throw a TypeError.
-    if (!parsed_url.is_valid())
+
+    // 3. Return the result of running the basic URL parser on url with parsedBase.
+    auto parsed = URLParser::parse(url, parsed_base);
+    return parsed.is_valid() ? parsed : Optional<AK::URL> {};
+}
+
+// https://url.spec.whatwg.org/#dom-url-url
+WebIDL::ExceptionOr<JS::NonnullGCPtr<URL>> URL::construct_impl(JS::Realm& realm, String const& url, Optional<String> const& base)
+{
+    auto& vm = realm.vm();
+
+    // 1. Let parsedURL be the result of running the API URL parser on url with base, if given.
+    auto parsed_url = parse_api_url(url, base);
+
+    // 2. If parsedURL is failure, then throw a TypeError.
+    if (!parsed_url.has_value())
         return WebIDL::SimpleException { WebIDL::SimpleExceptionType::TypeError, "Invalid URL"sv };
-    // 5. Let query be parsedURL’s query, if that is non-null, and the empty string otherwise.
-    auto query = parsed_url.query().is_null() ? String {} : TRY_OR_THROW_OOM(vm, String::from_deprecated_string(parsed_url.query()));
-    // 6. Set this’s URL to parsedURL.
-    // 7. Set this’s query object to a new URLSearchParams object.
+
+    // 3. Let query be parsedURL’s query, if that is non-null, and the empty string otherwise.
+    auto query = parsed_url->query().is_null() ? String {} : TRY_OR_THROW_OOM(vm, String::from_deprecated_string(parsed_url->query()));
+
+    // 4. Set this’s URL to parsedURL.
+    // 5. Set this’s query object to a new URLSearchParams object.
     auto query_object = MUST(URLSearchParams::construct_impl(realm, query));
-    // 8. Initialize this’s query object with query.
-    auto result_url = TRY(URL::create(realm, move(parsed_url), move(query_object)));
-    // 9. Set this’s query object’s URL object to this.
+
+    // 6. Initialize this’s query object with query.
+    auto result_url = TRY(URL::create(realm, parsed_url.release_value(), move(query_object)));
+
+    // 7. Set this’s query object’s URL object to this.
     result_url->m_query->m_url = result_url;
 
     return result_url;