implement window.stop, improve aborting document load

components/script/dom/document.rs

@@ -141,7 +141,7 @@ use style::shared_lock::{SharedRwLock as StyleSharedRwLock, SharedRwLockReadGuar
 use style::str::{split_html_space_chars, str_join};
 use style::stylesheet_set::DocumentStylesheetSet;
 use style::stylesheets::{CssRule, Stylesheet, Origin, OriginSet};
-use task_source::TaskSource;
+use task_source::{TaskSource, TaskSourceName};
 use time;
 use timers::OneshotTimerCallback;
 use url::Host;
@@ -2010,7 +2010,7 @@ impl Document {
     }
 
     // https://html.spec.whatwg.org/multipage/#abort-a-document
-    fn abort(&self) {
+    pub fn abort(&self) {
         // We need to inhibit the loader before anything else.
         self.loader.borrow_mut().inhibit_events();
 
@@ -2029,14 +2029,21 @@ impl Document {
         *self.asap_scripts_set.borrow_mut() = vec![];
         self.asap_in_order_scripts_list.clear();
         self.deferred_scripts.clear();
+        if self.loader.borrow_mut().cancel_all_loads() {
+            // If any loads were canceled.
+            self.salvageable.set(false);
+        };
 
-        // TODO: https://github.com/servo/servo/issues/15236
-        self.window.cancel_all_tasks();
+        // Also Step 2.
+        // Note: the spec says to discard any tasks queued for fetch.
+        // This cancels all tasks on the networking task source, which might be too broad.
+        // See https://github.com/whatwg/html/issues/3837
+        self.window.cancel_all_tasks_from_source(TaskSourceName::Networking);
 
         // Step 3.
         if let Some(parser) = self.get_current_parser() {
             parser.abort();
-            // TODO: salvageable flag.
+            self.salvageable.set(false);
         }
     }
 

components/script/dom/htmlimageelement.rs

@@ -268,7 +268,7 @@ impl HTMLImageElement {
 
         // This is a background load because the load blocker already fulfills the
         // purpose of delaying the document's load event.
-        document.loader().fetch_async_background(request, action_sender);
+        document.loader_mut().fetch_async_background(request, action_sender);
     }
 
     /// Step 14 of https://html.spec.whatwg.org/multipage/#update-the-image-data

components/script/dom/htmlmediaelement.rs

@@ -613,7 +613,7 @@ impl HTMLMediaElement {
                 ROUTER.add_route(action_receiver.to_opaque(), Box::new(move |message| {
                     listener.notify_fetch(message.to().unwrap());
                 }));
-                document.loader().fetch_async_background(request, action_sender);
+                document.loader_mut().fetch_async_background(request, action_sender);
             },
             Resource::Object => {
                 // FIXME(nox): Actually do something with the object.

components/script/dom/webidls/Window.webidl

@@ -25,7 +25,7 @@
   attribute DOMString status;
   void close();
   readonly attribute boolean closed;
-  //void stop();
+  void stop();
   //void focus();
   //void blur();
 

components/script/dom/window.rs

@@ -552,6 +552,13 @@ impl WindowMethods for Window {
         receiver.recv().unwrap();
     }
 
+    // https://html.spec.whatwg.org/multipage/#dom-window-stop
+    fn Stop(&self) {
+        // TODO: Cancel ongoing navigation.
+        let doc = self.Document();
+        doc.abort();
+    }
+
     // https://html.spec.whatwg.org/multipage/#dom-window-closed
     fn Closed(&self) -> bool {
         self.window_proxy.get()
@@ -1110,6 +1117,16 @@ impl Window {
         }
     }
 
+    /// Cancels all the tasks from a given task source.
+    /// This sets the current sentinel value to
+    /// `true` and replaces it with a brand new one for future tasks.
+    pub fn cancel_all_tasks_from_source(&self, task_source_name: TaskSourceName) {
+        let mut ignore_flags = self.ignore_further_async_events.borrow_mut();
+        let flag = ignore_flags.entry(task_source_name).or_insert(Default::default());
+        let cancelled = mem::replace(&mut *flag, Default::default());
+        cancelled.store(true, Ordering::Relaxed);
+    }
+
     pub fn clear_js_runtime(&self) {
         // We tear down the active document, which causes all the attached
         // nodes to dispose of their layout data. This messages the layout