LibURL: Replace Host's Empty state with making Url's Host optional

A couple of reasons:
- Origin's Host (when in the tuple state) can't be null
- There's an "empty host" concept in the spec which is NOT the same as a
  null Host, and that was confusing me.

Libraries/LibCore/Proxy.h

@@ -36,9 +36,9 @@ struct ProxyData {
 
         proxy_data.type = ProxyData::Type::SOCKS5;
 
-        if (!url.host().has<URL::IPv4Address>())
+        if (!url.host().has_value() || !url.host()->has<URL::IPv4Address>())
             return Error::from_string_literal("Invalid proxy host, must be an IPv4 address");
-        proxy_data.host_ipv4 = url.host().get<URL::IPv4Address>();
+        proxy_data.host_ipv4 = url.host()->get<URL::IPv4Address>();
 
         auto port = url.port();
         if (!port.has_value())

Libraries/LibURL/Host.h

@@ -26,6 +26,6 @@ using IPv6Address = Array<u16, 8>;
 // https://url.spec.whatwg.org/#concept-host
 // A host is a domain, an IP address, an opaque host, or an empty host. Typically a host serves as a network address,
 // but it is sometimes used as opaque identifier in URLs where a network address is not necessary.
-using Host = Variant<IPv4Address, IPv6Address, String, Empty>;
+using Host = Variant<IPv4Address, IPv6Address, String>;
 
 }

Libraries/LibURL/Parser.cpp

@@ -1574,7 +1574,7 @@ URL Parser::basic_parse(StringView raw_input, Optional<URL> const& base_url, URL
                     continue;
             }
             // 5. Otherwise, if state override is given and url’s host is null, append the empty string to url’s path.
-            else if (state_override.has_value() && url->host().has<Empty>()) {
+            else if (state_override.has_value() && !url->host().has_value()) {
                 url->append_slash();
             }
             break;

Libraries/LibURL/URL.cpp

@@ -88,7 +88,7 @@ void URL::set_host(Host host)
 // https://url.spec.whatwg.org/#concept-host-serializer
 ErrorOr<String> URL::serialized_host() const
 {
-    return Parser::serialize_host(m_data->host);
+    return Parser::serialize_host(m_data->host.value());
 }
 
 void URL::set_port(Optional<u16> port)
@@ -119,7 +119,7 @@ void URL::append_path(StringView path)
 bool URL::cannot_have_a_username_or_password_or_port() const
 {
     // A URL cannot have a username/password/port if its host is null or the empty string, or its scheme is "file".
-    return m_data->host.has<Empty>() || m_data->host == String {} || m_data->scheme == "file"sv;
+    return !m_data->host.has_value() || m_data->host == String {} || m_data->scheme == "file"sv;
 }
 
 // FIXME: This is by no means complete.
@@ -142,8 +142,8 @@ bool URL::compute_validity() const
             return false;
     }
 
-    // NOTE: A file URL's host should be the empty string for localhost, not null.
-    if (m_data->scheme == "file" && m_data->host.has<Empty>())
+    // FIXME: A file URL's host should be the empty string for localhost, not null.
+    if (m_data->scheme == "file" && !m_data->host.has_value())
         return false;
 
     return true;
@@ -252,7 +252,7 @@ ByteString URL::serialize(ExcludeFragment exclude_fragment) const
     output.append(':');
 
     // 2. If url’s host is non-null:
-    if (!m_data->host.has<Empty>()) {
+    if (m_data->host.has_value()) {
         // 1. Append "//" to output.
         output.append("//"sv);
 
@@ -285,7 +285,7 @@ ByteString URL::serialize(ExcludeFragment exclude_fragment) const
     if (cannot_be_a_base_url()) {
         output.append(m_data->paths[0]);
     } else {
-        if (m_data->host.has<Empty>() && m_data->paths.size() > 1 && m_data->paths[0].is_empty())
+        if (!m_data->host.has_value() && m_data->paths.size() > 1 && m_data->paths[0].is_empty())
             output.append("/."sv);
         for (auto& segment : m_data->paths) {
             output.append('/');
@@ -321,7 +321,7 @@ ByteString URL::serialize_for_display() const
     builder.append(m_data->scheme);
     builder.append(':');
 
-    if (!m_data->host.has<Empty>()) {
+    if (m_data->host.has_value()) {
         builder.append("//"sv);
         builder.append(serialized_host().release_value_but_fixme_should_propagate_errors());
         if (m_data->port.has_value())
@@ -331,7 +331,7 @@ ByteString URL::serialize_for_display() const
     if (cannot_be_a_base_url()) {
         builder.append(m_data->paths[0]);
     } else {
-        if (m_data->host.has<Empty>() && m_data->paths.size() > 1 && m_data->paths[0].is_empty())
+        if (!m_data->host.has_value() && m_data->paths.size() > 1 && m_data->paths[0].is_empty())
             builder.append("/."sv);
         for (auto& segment : m_data->paths) {
             builder.append('/');
@@ -391,7 +391,7 @@ Origin URL::origin() const
     // -> "wss"
     if (scheme().is_one_of("ftp"sv, "http"sv, "https"sv, "ws"sv, "wss"sv)) {
         // Return the tuple origin (url’s scheme, url’s host, url’s port, null).
-        return Origin(scheme().to_byte_string(), host(), port());
+        return Origin(scheme().to_byte_string(), host().value(), port());
     }
 
     // -> "file"

Libraries/LibURL/URL.h

@@ -83,7 +83,7 @@ public:
     String const& scheme() const { return m_data->scheme; }
     String const& username() const { return m_data->username; }
     String const& password() const { return m_data->password; }
-    Host const& host() const { return m_data->host; }
+    Optional<Host> const& host() const { return m_data->host; }
     ErrorOr<String> serialized_host() const;
     ByteString basename() const;
     Optional<String> const& query() const { return m_data->query; }
@@ -171,7 +171,7 @@ private:
         String password;
 
         // A URL’s host is null or a host. It is initially null.
-        Host host;
+        Optional<Host> host;
 
         // A URL’s port is either null or a 16-bit unsigned integer that identifies a networking port. It is initially null.
         Optional<u16> port;

Libraries/LibWeb/DOMURL/DOMURL.cpp

@@ -284,7 +284,7 @@ WebIDL::ExceptionOr<String> DOMURL::host() const
     auto& url = m_url;
 
     // 2. If url’s host is null, then return the empty string.
-    if (url.host().has<Empty>())
+    if (!url.host().has_value())
         return String {};
 
     // 3. If url’s port is null, return url’s host, serialized.
@@ -312,7 +312,7 @@ WebIDL::ExceptionOr<String> DOMURL::hostname() const
     auto& vm = realm().vm();
 
     // 1. If this’s URL’s host is null, then return the empty string.
-    if (m_url.host().has<Empty>())
+    if (!m_url.host().has_value())
         return String {};
 
     // 2. Return this’s URL’s host, serialized.
@@ -477,6 +477,7 @@ void DOMURL::set_hash(String const& hash)
 }
 
 // https://url.spec.whatwg.org/#concept-domain
+// FIXME: Move into URL::Host
 bool host_is_domain(URL::Host const& host)
 {
     // A domain is a non-empty ASCII string that identifies a realm within a network.

Libraries/LibWeb/Fetch/Fetching/Fetching.cpp

@@ -322,7 +322,7 @@ WebIDL::ExceptionOr<GC::Ptr<PendingResponse>> main_fetch(JS::Realm& realm, Infra
         // - request’s current URL’s scheme is "http"
         request->current_url().scheme() == "http"sv
         // - request’s current URL’s host is a domain
-        && DOMURL::host_is_domain(request->current_url().host())
+        && request->current_url().host().has_value() && DOMURL::host_is_domain(request->current_url().host().value())
         // FIXME: - Matching request’s current URL’s host per Known HSTS Host Domain Name Matching results in either a
         //          superdomain match with an asserted includeSubDomains directive or a congruent match (with or without an
         //          asserted includeSubDomains directive) [HSTS]; or DNS resolution for the request finds a matching HTTPS RR

Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -44,7 +44,7 @@ bool url_matches_about_blank(URL::URL const& url)
         && url.paths().size() == 1 && url.paths()[0] == "blank"sv
         && url.username().is_empty()
         && url.password().is_empty()
-        && url.host().has<Empty>();
+        && !url.host().has_value();
 }
 
 // https://html.spec.whatwg.org/multipage/urls-and-fetching.html#matches-about:srcdoc
@@ -56,7 +56,7 @@ bool url_matches_about_srcdoc(URL::URL const& url)
         && !url.query().has_value()
         && url.username().is_empty()
         && url.password().is_empty()
-        && url.host().has<Empty>();
+        && !url.host().has_value();
 }
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#determining-the-origin

Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp

@@ -167,7 +167,7 @@ String HTMLHyperlinkElementUtils::host() const
     auto const& url = m_url;
 
     // 3. If url or url's host is null, return the empty string.
-    if (!url.has_value() || url->host().has<Empty>())
+    if (!url.has_value() || !url->host().has_value())
         return String {};
 
     // 4. If url's port is null, return url's host, serialized.
@@ -206,7 +206,8 @@ String HTMLHyperlinkElementUtils::hostname() const
     URL::URL url(href());
 
     // 3. If url or url's host is null, return the empty string.
-    if (url.host().has<Empty>())
+    // FIXME: How can url be null here?
+    if (!url.host().has_value())
         return String {};
 
     // 4. Return url's host, serialized.

Libraries/LibWeb/HTML/Location.cpp

@@ -203,7 +203,7 @@ WebIDL::ExceptionOr<String> Location::host() const
     auto url = this->url();
 
     // 3. If url's host is null, return the empty string.
-    if (url.host().has<Empty>())
+    if (!url.host().has_value())
         return String {};
 
     // 4. If url's port is null, return url's host, serialized.
@@ -233,7 +233,7 @@ WebIDL::ExceptionOr<String> Location::hostname() const
     auto url = this->url();
 
     // 2. If this's url's host is null, return the empty string.
-    if (url.host().has<Empty>())
+    if (!url.host().has_value())
         return String {};
 
     // 3. Return this's url's host, serialized.

Libraries/LibWeb/HTML/WorkerLocation.cpp

@@ -46,7 +46,7 @@ WebIDL::ExceptionOr<String> WorkerLocation::host() const
     auto const& url = m_global_scope->url();
 
     // 2. If url's host is null, return the empty string.
-    if (url.host().has<Empty>())
+    if (!url.host().has_value())
         return String {};
 
     // 3. If url's port is null, return url's host, serialized.
@@ -67,11 +67,11 @@ WebIDL::ExceptionOr<String> WorkerLocation::hostname() const
     auto const& host = m_global_scope->url().host();
 
     // 2. If host is null, return the empty string.
-    if (host.has<Empty>())
+    if (!host.has_value())
         return String {};
 
     // 3. Return host, serialized.
-    return TRY_OR_THROW_OOM(vm, URL::Parser::serialize_host(host));
+    return TRY_OR_THROW_OOM(vm, URL::Parser::serialize_host(host.value()));
 }
 
 // https://html.spec.whatwg.org/multipage/workers.html#dom-workerlocation-port

Libraries/LibWeb/MixedContent/AbstractOperations.cpp

@@ -20,7 +20,7 @@ void upgrade_a_mixed_content_request_to_a_potentially_trustworthy_url_if_appropr
         SecureContexts::is_url_potentially_trustworthy(request.url()) == SecureContexts::Trustworthiness::PotentiallyTrustworthy
 
         // 2. request’s URL’s host is an IP address.
-        || request.url().host().has<URL::IPv4Address>() || request.url().host().has<URL::IPv6Address>()
+        || (request.url().host().has_value() && (request.url().host()->has<URL::IPv4Address>() || request.url().host()->has<URL::IPv6Address>()))
 
         // 3. § 4.3 Does settings prohibit mixed security contexts? returns "Does Not Restrict Mixed Security Contents" when applied to request’s client.
         || does_settings_prohibit_mixed_security_contexts(request.client()) == ProhibitsMixedSecurityContexts::DoesNotRestrictMixedSecurityContexts

Libraries/LibWeb/XHR/XMLHttpRequest.cpp

@@ -494,7 +494,7 @@ WebIDL::ExceptionOr<void> XMLHttpRequest::open(String const& method_string, Stri
     // NOTE: This is handled in the overload lacking the async argument.
 
     // 8. If parsedURL’s host is non-null, then:
-    if (!parsed_url.host().has<Empty>()) {
+    if (parsed_url.host().has_value()) {
         // 1. If the username argument is not null, set the username given parsedURL and username.
         if (username.has_value())
             parsed_url.set_username(username.value());

Libraries/LibWebView/CookieJar.cpp

@@ -220,7 +220,7 @@ void CookieJar::expire_cookies_with_time_offset(AK::Duration offset)
 // https://www.ietf.org/archive/id/draft-ietf-httpbis-rfc6265bis-15.html#section-5.1.2
 Optional<String> CookieJar::canonicalize_domain(const URL::URL& url)
 {
-    if (!url.is_valid() || url.host().has<Empty>())
+    if (!url.is_valid() || !url.host().has_value())
         return {};
 
     // 1. Convert the host name to a sequence of individual domain name labels.

Libraries/LibWebView/ViewImplementation.cpp

@@ -570,7 +570,7 @@ void ViewImplementation::handle_web_content_process_crash(LoadErrorPage load_err
         builder.append(escape_html_entities(m_url.to_byte_string()));
         builder.append("</title></head><body>"sv);
         builder.append("<h1>Web page crashed"sv);
-        if (!m_url.host().has<Empty>()) {
+        if (m_url.host().has_value()) {
             builder.appendff(" on {}", escape_html_entities(m_url.serialized_host().release_value_but_fixme_should_propagate_errors()));
         }
         builder.append("</h1>"sv);

Tests/LibURL/TestURL.cpp

@@ -206,7 +206,7 @@ TEST_CASE(about_url)
     URL::URL url("about:blank"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "about");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize_path(), "blank");
     EXPECT(!url.query().has_value());
     EXPECT(!url.fragment().has_value());
@@ -218,7 +218,7 @@ TEST_CASE(mailto_url)
     URL::URL url("mailto:mail@example.com"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "mailto");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.port_or_default(), 0);
     EXPECT_EQ(url.path_segment_count(), 1u);
     EXPECT_EQ(url.path_segment_at_index(0), "mail@example.com");
@@ -232,7 +232,7 @@ TEST_CASE(mailto_url_with_subject)
     URL::URL url("mailto:mail@example.com?subject=test"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "mailto");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.port_or_default(), 0);
     EXPECT_EQ(url.path_segment_count(), 1u);
     EXPECT_EQ(url.path_segment_at_index(0), "mail@example.com");

Tests/LibWeb/TestFetchURL.cpp

@@ -14,7 +14,7 @@ TEST_CASE(data_url)
     URL::URL url("data:text/html,test"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize(), "data:text/html,test");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
@@ -27,7 +27,7 @@ TEST_CASE(data_url_default_mime_type)
     URL::URL url("data:,test"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize(), "data:,test");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
@@ -40,7 +40,7 @@ TEST_CASE(data_url_encoded)
     URL::URL url("data:text/html,Hello%20friends%2C%0X%X0"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize(), "data:text/html,Hello%20friends%2C%0X%X0");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
@@ -53,7 +53,7 @@ TEST_CASE(data_url_base64_encoded)
     URL::URL url("data:text/html;base64,dGVzdA=="sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize(), "data:text/html;base64,dGVzdA==");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
@@ -66,7 +66,7 @@ TEST_CASE(data_url_base64_encoded_default_mime_type)
     URL::URL url("data:;base64,dGVzdA=="sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize(), "data:;base64,dGVzdA==");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
@@ -79,7 +79,7 @@ TEST_CASE(data_url_base64_encoded_with_whitespace)
     URL::URL url("data: text/html ;     bAsE64 , dGVz dA== "sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
     EXPECT_EQ(url.serialize(), "data: text/html ;     bAsE64 , dGVz dA==");
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
@@ -92,7 +92,7 @@ TEST_CASE(data_url_base64_encoded_with_inline_whitespace)
     URL::URL url("data:text/javascript;base64,%20ZD%20Qg%0D%0APS%20An%20Zm91cic%0D%0A%207%20"sv);
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
     EXPECT_EQ(data_url.mime_type.serialized(), "text/javascript");
@@ -105,7 +105,7 @@ TEST_CASE(data_url_completed_with_fragment)
     EXPECT(url.is_valid());
     EXPECT_EQ(url.scheme(), "data");
     EXPECT_EQ(url.fragment(), "a");
-    EXPECT(url.host().has<Empty>());
+    EXPECT(!url.host().has_value());
 
     auto data_url = TRY_OR_FAIL(Web::Fetch::Infrastructure::process_data_url(url));
     EXPECT_EQ(data_url.mime_type.serialized(), "text/plain");