AK: Add hostname parameter to URL::create_with_file_scheme()

This adds a hostname parameter as the third parameter to
URL::create_with_file_scheme(). If the hostname is "localhost", it will
be ignored (as per the URL specification).

This can for example be used by ls(1) to create more conforming file
URLs.

AK/URL.cpp

@@ -178,14 +178,17 @@ u16 URL::default_port_for_scheme(const StringView& scheme)
  return 0;
 }
 
-URL URL::create_with_file_scheme(const String& path, const String& fragment)
+URL URL::create_with_file_scheme(const String& path, const String& fragment, const String& hostname)
 {
  LexicalPath lexical_path(path);
  if (!lexical_path.is_valid() || !lexical_path.is_absolute())
  return {};
+
  URL url;
  url.set_scheme("file");
- url.set_host(String::empty());
+ // NOTE: If the hostname is localhost (or null, which implies localhost), it should be set to the empty string.
+ // This is because a file URL always needs a non-null hostname.
+ url.set_host(hostname.is_null() || hostname == "localhost" ? String::empty() : hostname);
  url.set_paths(lexical_path.parts());
  // NOTE: To indicate that we want to end the path with a slash, we have to append an empty path segment.
  if (path.ends_with('/'))

AK/URL.h

@@ -92,7 +92,7 @@ class URL {
  const String& data_payload() const { return m_data_payload; }
 
  static URL create_with_url_or_path(const String&);
- static URL create_with_file_scheme(const String& path, const String& fragment = {});
+ static URL create_with_file_scheme(const String& path, const String& fragment = {}, const String& hostname = {});
  static URL create_with_file_protocol(const String& path, const String& fragment = {}) { return create_with_file_scheme(path, fragment); }
  static URL create_with_data(const StringView& mime_type, const StringView& payload, bool is_base64 = false);