Report errors from ScriptPort trait methods.

components/script/dom/dedicatedworkerglobalscope.rs

@@ -94,10 +94,11 @@ impl ScriptChan for WorkerThreadWorkerChan {
 }
 
 impl ScriptPort for Receiver<(TrustedWorkerAddress, WorkerScriptMsg)> {
-    fn recv(&self) -> CommonScriptMsg {
-        match self.recv().unwrap().1 {
-            WorkerScriptMsg::Common(script_msg) => script_msg,
-            WorkerScriptMsg::DOMMessage(_) => panic!("unexpected worker event message!"),
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        match self.recv().map(|(_, msg)| msg) {
+            Ok(WorkerScriptMsg::Common(script_msg)) => Ok(script_msg),
+            Ok(WorkerScriptMsg::DOMMessage(_)) => panic!("unexpected worker event message!"),
+            Err(_) => Err(()),
         }
     }
 }

components/script/dom/xmlhttprequest.rs

@@ -1337,7 +1337,7 @@ impl XMLHttpRequest {
 
         if let Some(script_port) = script_port {
             loop {
-                global.process_event(script_port.recv());
+                global.process_event(script_port.recv().unwrap());
                 let context = context.lock().unwrap();
                 let sync_status = context.sync_status.borrow();
                 if let Some(ref status) = *sync_status {

components/script/script_thread.rs

@@ -282,35 +282,37 @@ impl OpaqueSender<CommonScriptMsg> for Box<ScriptChan + Send> {
 /// APIs that need to abstract over multiple kinds of event loops (worker/main thread) with
 /// different Receiver interfaces.
 pub trait ScriptPort {
-    fn recv(&self) -> CommonScriptMsg;
+    fn recv(&self) -> Result<CommonScriptMsg, ()>;
 }
 
 impl ScriptPort for Receiver<CommonScriptMsg> {
-    fn recv(&self) -> CommonScriptMsg {
-        self.recv().unwrap()
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        self.recv().map_err(|_| ())
     }
 }
 
 impl ScriptPort for Receiver<MainThreadScriptMsg> {
-    fn recv(&self) -> CommonScriptMsg {
-        match self.recv().unwrap() {
-            MainThreadScriptMsg::Common(script_msg) => script_msg,
-            _ => panic!("unexpected main thread event message!")
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        match self.recv() {
+            Ok(MainThreadScriptMsg::Common(script_msg)) => Ok(script_msg),
+            Ok(_) => panic!("unexpected main thread event message!"),
+            _ => Err(()),
         }
     }
 }
 
 impl ScriptPort for Receiver<(TrustedWorkerAddress, CommonScriptMsg)> {
-    fn recv(&self) -> CommonScriptMsg {
-        self.recv().unwrap().1
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        self.recv().map(|(_, msg)| msg).map_err(|_| ())
     }
 }
 
 impl ScriptPort for Receiver<(TrustedWorkerAddress, MainThreadScriptMsg)> {
-    fn recv(&self) -> CommonScriptMsg {
-        match self.recv().unwrap().1 {
-            MainThreadScriptMsg::Common(script_msg) => script_msg,
-            _ => panic!("unexpected main thread event message!")
+    fn recv(&self) -> Result<CommonScriptMsg, ()> {
+        match self.recv().map(|(_, msg)| msg) {
+            Ok(MainThreadScriptMsg::Common(script_msg)) => Ok(script_msg),
+            Ok(_) => panic!("unexpected main thread event message!"),
+            _ => Err(()),
         }
     }
 }