Implement error reporting for workers.

Fixes #3311.
Fixes #13158.

components/script/dom/dedicatedworkerglobalscope.rs

@@ -10,15 +10,18 @@ use dom::bindings::cell::DOMRefCell;
 use dom::bindings::codegen::Bindings::DedicatedWorkerGlobalScopeBinding;
 use dom::bindings::codegen::Bindings::DedicatedWorkerGlobalScopeBinding::DedicatedWorkerGlobalScopeMethods;
 use dom::bindings::codegen::Bindings::EventHandlerBinding::EventHandlerNonNull;
-use dom::bindings::error::ErrorResult;
+use dom::bindings::error::{ErrorInfo, ErrorResult};
 use dom::bindings::global::{GlobalRef, global_root_from_context};
 use dom::bindings::inheritance::Castable;
 use dom::bindings::js::{Root, RootCollection};
 use dom::bindings::reflector::Reflectable;
 use dom::bindings::str::DOMString;
 use dom::bindings::structuredclone::StructuredCloneData;
+use dom::errorevent::ErrorEvent;
+use dom::event::{Event, EventBubbles, EventCancelable};
+use dom::eventtarget::EventTarget;
 use dom::messageevent::MessageEvent;
-use dom::worker::{TrustedWorkerAddress, WorkerMessageHandler};
+use dom::worker::{TrustedWorkerAddress, WorkerErrorHandler, WorkerMessageHandler};
 use dom::workerglobalscope::WorkerGlobalScope;
 use ipc_channel::ipc::{self, IpcReceiver, IpcSender};
 use ipc_channel::router::ROUTER;
@@ -32,6 +35,7 @@ use rand::random;
 use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, StackRootTLS, get_reports, new_rt_and_cx};
 use script_runtime::ScriptThreadEventCategory::WorkerEvent;
 use script_traits::{TimerEvent, TimerSource, WorkerGlobalScopeInit, WorkerScriptLoadOrigin};
+use std::cell::Cell;
 use std::mem::replace;
 use std::sync::{Arc, Mutex};
 use std::sync::atomic::AtomicBool;
@@ -88,6 +92,8 @@ pub struct DedicatedWorkerGlobalScope {
     #[ignore_heap_size_of = "Can't measure trait objects"]
     /// Sender to the parent thread.
     parent_sender: Box<ScriptChan + Send>,
+    /// https://html.spec.whatwg.org/multipage/#in-error-reporting-mode
+    in_error_reporting_mode: Cell<bool>
 }
 
 impl DedicatedWorkerGlobalScope {
@@ -116,6 +122,7 @@ impl DedicatedWorkerGlobalScope {
             timer_event_port: timer_event_port,
             parent_sender: parent_sender,
             worker: DOMRefCell::new(None),
+            in_error_reporting_mode: Cell::new(false),
         }
     }
 
@@ -339,6 +346,41 @@ impl DedicatedWorkerGlobalScope {
             }
         }
     }
+
+    /// https://html.spec.whatwg.org/multipage/#report-the-error
+    pub fn report_an_error(&self, error_info: ErrorInfo, value: HandleValue) {
+        // Step 1.
+        if self.in_error_reporting_mode.get() {
+            return;
+        }
+
+        // Step 2.
+        self.in_error_reporting_mode.set(true);
+
+        // Steps 3-12.
+        let event = ErrorEvent::new(GlobalRef::Worker(self.upcast()),
+                                    atom!("error"),
+                                    EventBubbles::DoesNotBubble,
+                                    EventCancelable::Cancelable,
+                                    error_info.message.as_str().into(),
+                                    error_info.filename.as_str().into(),
+                                    error_info.lineno,
+                                    error_info.column,
+                                    value);
+
+        // Step 13.
+        let handled = !event.upcast::<Event>().fire(self.upcast::<EventTarget>());
+        if !handled {
+            let worker = self.worker.borrow().as_ref().unwrap().clone();
+            // TODO: Should use the DOM manipulation task source.
+            self.parent_sender
+                .send(CommonScriptMsg::RunnableMsg(WorkerEvent,
+                                                   box WorkerErrorHandler::new(worker, error_info)))
+                .unwrap();
+        }
+
+        self.in_error_reporting_mode.set(false);
+    }
 }
 
 #[allow(unsafe_code)]