Implement the overrideMimeType method for XMLHttpRequest

components/script/dom/bindings/trace.rs

@@ -45,6 +45,7 @@ use euclid::size::Size2D;
 use html5ever::tree_builder::QuirksMode;
 use hyper::header::Headers;
 use hyper::method::Method;
+use hyper::mime::Mime;
 use ipc_channel::ipc::{IpcReceiver, IpcSender};
 use js::jsapi::JS_CallUnbarrieredObjectTracer;
 use js::jsapi::{GCTraceKindToAscii, Heap, JSGCTraceKind, JSObject, JSTracer, JS_CallObjectTracer, JS_CallValueTracer};
@@ -286,6 +287,7 @@ no_jsmanaged_fields!(PseudoElement);
 no_jsmanaged_fields!(Length);
 no_jsmanaged_fields!(ElementState);
 no_jsmanaged_fields!(DOMString);
+no_jsmanaged_fields!(Mime);
 
 impl JSTraceable for Box<ScriptChan + Send> {
     #[inline]

components/script/dom/webidls/XMLHttpRequest.webidl

@@ -65,7 +65,8 @@ interface XMLHttpRequest : XMLHttpRequestEventTarget {
   readonly attribute ByteString statusText;
   ByteString? getResponseHeader(ByteString name);
   ByteString getAllResponseHeaders();
-  // void overrideMimeType(DOMString mime);
+  [Throws]
+  void overrideMimeType(DOMString mime);
   [SetterThrows]
            attribute XMLHttpRequestResponseType responseType;
   readonly attribute any response;

components/script/dom/xmlhttprequest.rs

@@ -121,6 +121,9 @@ pub struct XMLHttpRequest {
     response_xml: MutNullableHeap<JS<Document>>,
     #[ignore_heap_size_of = "Defined in hyper"]
     response_headers: DOMRefCell<Headers>,
+    override_mime_type: DOMRefCell<Option<Mime>>,
+    #[ignore_heap_size_of = "Defined in rust-encoding"]
+    override_charset: DOMRefCell<Option<EncodingRef>>,
 
     // Associated concepts
     request_method: DOMRefCell<Method>,
@@ -158,6 +161,8 @@ impl XMLHttpRequest {
             response_type: Cell::new(_empty),
             response_xml: Default::default(),
             response_headers: DOMRefCell::new(Headers::new()),
+            override_mime_type: DOMRefCell::new(None),
+            override_charset: DOMRefCell::new(None),
 
             request_method: DOMRefCell::new(Method::Get),
             request_url: DOMRefCell::new(None),
@@ -644,6 +649,21 @@ impl XMLHttpRequestMethods for XMLHttpRequest {
         ByteString::new(self.filter_response_headers().to_string().into_bytes())
     }
 
+    // https://xhr.spec.whatwg.org/#the-overridemimetype()-method
+    fn OverrideMimeType(&self, mime: DOMString) -> ErrorResult {
+        match self.ready_state.get() {
+            XMLHttpRequestState::Loading | XMLHttpRequestState::Done => return Err(Error::InvalidState),
+            _ => {},
+        }
+        let override_mime = try!(mime.parse::<Mime>().map_err(|_| Error::Syntax));
+        *self.override_mime_type.borrow_mut() = Some(override_mime.clone());
+        let value = override_mime.get_param(mime::Attr::Charset);
+        *self.override_charset.borrow_mut() = value.and_then(|value| {
+                encoding_from_whatwg_label(value)
+        });
+        Ok(())
+    }
+
     // https://xhr.spec.whatwg.org/#the-responsetype-attribute
     fn ResponseType(&self) -> XMLHttpRequestResponseType {
         self.response_type.get()
@@ -987,6 +1007,7 @@ impl XMLHttpRequest {
         }
     }
 
+    //FIXME: add support for override_mime_type and override_charset
     fn text_response(&self) -> String {
         let mut encoding = UTF_8 as EncodingRef;
         match self.response_headers.borrow().get() {