Correctly handle flag local_urls_only

In function Request::fetch_main, flag local_urls_only (if set)
should allow fetching local urls only. Before this change, the flag had
the inverse behaviour.

components/net/fetch/methods.rs

@@ -110,11 +110,8 @@ fn main_fetch(request: Rc<Request>, cors_flag: bool, recursive_flag: bool) -> Re
     let mut response = None;
 
     // Step 2
-    if request.local_urls_only {
+    if request.local_urls_only && !url_is_local(&request.current_url()) {
-        match &*request.current_url().scheme {
+        response = Some(Response::network_error());
-            "about" | "blob" | "data" | "filesystem" => response = Some(Response::network_error()),
-            _ => { }
-        };
     }
 
     // Step 3
@@ -1047,6 +1044,13 @@ fn includes_credentials(url: &Url) -> bool {
     false
 }
 
+fn url_is_local(url: &Url) -> bool {
+    match &*url.scheme {
+        "about" | "blob" | "data" | "filesystem" => true,
+        _ => false
+    }
+}
+
 fn response_needs_revalidation(_response: &Response) -> bool {
     // TODO this function
     false

components/net_traits/request.rs

@@ -257,4 +257,8 @@ impl Request {
             _ => false
         }
     }
+
+    pub fn set_local_urls_only(&mut self, local_urls_only: bool) {
+        self.local_urls_only = local_urls_only;
+    }
 }

tests/unit/net/fetch.rs

@@ -268,6 +268,35 @@ fn test_fetch_response_is_opaque_redirect_filtered() {
     }
 }
 
+#[test]
+fn test_fetch_with_local_urls_only() {
+    // If flag `local_urls_only` is set, fetching a non-local URL must result in network error.
+
+    static MESSAGE: &'static [u8] = b"";
+    let handler = move |_: HyperRequest, response: HyperResponse| {
+        response.send(MESSAGE).unwrap();
+    };
+    let (mut server, server_url) = make_server(handler);
+
+    let do_fetch = |url: Url| {
+        let origin = Origin::Origin(url.origin());
+        let mut request = Request::new(url, Some(origin), false);
+        request.referer = Referer::NoReferer;
+
+        // Set the flag.
+        request.set_local_urls_only(true);
+
+        let wrapped_request = Rc::new(request);
+        fetch(wrapped_request)
+    };
+
+    let local_url = Url::parse("about:config").unwrap();
+    assert!(do_fetch(local_url).is_network_error());
+    assert!(!do_fetch(server_url).is_network_error());
+
+    let _ = server.close();
+}
+
 fn test_fetch_redirect_count(message: &'static [u8], redirect_cap: u32) -> Response {
 
     let handler = move |request: HyperRequest, mut response: HyperResponse| {