Bug 1288768 - Better error reporting for network errors in workers

2 files changed, 116 insertions, 20 deletions

diff --git a/dom/workers/WorkerPrivate.cpp b/dom/workers/WorkerPrivate.cpp
index c2ab4aca38..bd8a33032e 100644
--- a/dom/workers/WorkerPrivate.cpp
+++ b/dom/workers/WorkerPrivate.cpp
@@ -495,6 +495,82 @@ private:
   }
 };
 
+class ReportCompileErrorRunnable final : public WorkerRunnable
+{
+public:
+  static void
+  CreateAndDispatch(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+  {
+    MOZ_ASSERT(aWorkerPrivate);
+    aWorkerPrivate->AssertIsOnWorkerThread();
+
+    RefPtr<ReportCompileErrorRunnable> runnable =
+      new ReportCompileErrorRunnable(aCx, aWorkerPrivate);
+    runnable->Dispatch();
+  }
+
+private:
+  ReportCompileErrorRunnable(JSContext* aCx, WorkerPrivate* aWorkerPrivate)
+    : WorkerRunnable(aWorkerPrivate, ParentThreadUnchangedBusyCount)
+  {
+    aWorkerPrivate->AssertIsOnWorkerThread();
+  }
+
+  void
+  PostDispatch(WorkerPrivate* aWorkerPrivate, bool aDispatchResult) override
+  {
+    aWorkerPrivate->AssertIsOnWorkerThread();
+
+    // Dispatch may fail if the worker was canceled, no need to report that as
+    // an error, so don't call base class PostDispatch.
+  }
+
+  bool
+  WorkerRun(JSContext* aCx, WorkerPrivate* aWorkerPrivate) override
+  {
+    if (aWorkerPrivate->IsFrozen() ||
+        aWorkerPrivate->IsParentWindowPaused()) {
+      MOZ_ASSERT(!IsDebuggerRunnable());
+      aWorkerPrivate->QueueRunnable(this);
+      return true;
+    }
+
+    if (aWorkerPrivate->IsSharedWorker()) {
+      aWorkerPrivate->BroadcastErrorToSharedWorkers(aCx, EmptyString(),
+                                                    EmptyString(),
+                                                    EmptyString(), 0, 0,
+                                                    JSREPORT_ERROR,
+                                                    /* isErrorEvent */ false);
+      return true;
+    }
+
+    if (aWorkerPrivate->IsServiceWorker()) {
+      RefPtr<ServiceWorkerManager> swm = ServiceWorkerManager::GetInstance();
+      if (swm) {
+        swm->HandleError(aCx, aWorkerPrivate->GetPrincipal(),
+                         aWorkerPrivate->WorkerName(),
+                         aWorkerPrivate->ScriptURL(),
+                         EmptyString(), EmptyString(), EmptyString(),
+                         0, 0, JSREPORT_ERROR, JSEXN_ERR);
+      }
+      return true;
+    }
+
+    if (!aWorkerPrivate->IsAcceptingEvents()) {
+      return true;
+    }
+
+    RefPtr<Event> event =
+      Event::Constructor(aWorkerPrivate, NS_LITERAL_STRING("error"),
+                         EventInit());
+    event->SetTrusted(true);
+
+    nsEventStatus status = nsEventStatus_eIgnore;
+    aWorkerPrivate->DispatchDOMEvent(nullptr, event, nullptr, &status);
+    return true;
+  }
+};
+
 class CompileScriptRunnable final : public WorkerRunnable
 {
   nsString mScriptURL;
@@ -538,9 +614,15 @@ private:
     }
 
     // Make sure to propagate exceptions from rv onto aCx, so that they will get
-    // reported after we return.  We do this for all failures on rv, because now
-    // we're using rv to track all the state we care about.
-    //
+    // reported after we return.  We want to propagate just JS exceptions,
+    // because all the other errors are handled when the script is loaded.
+    // See: https://dom.spec.whatwg.org/#concept-event-fire
+    if (rv.Failed() && !rv.IsJSException()) {
+      ReportCompileErrorRunnable::CreateAndDispatch(aCx, aWorkerPrivate);
+      rv.SuppressException();
+      return false;
+    }
+
     // This is a little dumb, but aCx is in the null compartment here because we
     // set it up that way in our Run(), since we had not created the global at
     // that point yet.  So we need to enter the compartment of our global,
@@ -1171,7 +1253,8 @@ private:
       if (aWorkerPrivate->IsSharedWorker()) {
         aWorkerPrivate->BroadcastErrorToSharedWorkers(aCx, mMessage, mFilename,
                                                       mLine, mLineNumber,
-                                                      mColumnNumber, mFlags);
+                                                      mColumnNumber, mFlags,
+                                                      /* isErrorEvent */ true);
         return true;
       }
 
@@ -3250,7 +3333,8 @@ WorkerPrivateParent<Derived>::BroadcastErrorToSharedWorkers(
                                                     const nsAString& aLine,
                                                     uint32_t aLineNumber,
                                                     uint32_t aColumnNumber,
-                                                    uint32_t aFlags)
+                                                    uint32_t aFlags,
+                                                    bool aIsErrorEvent)
 {
   AssertIsOnMainThread();
 
@@ -3281,31 +3365,42 @@ WorkerPrivateParent<Derived>::BroadcastErrorToSharedWorkers(
     // May be null.
     nsPIDOMWindowInner* window = sharedWorker->GetOwner();
 
-    RootedDictionary<ErrorEventInit> errorInit(aCx);
-    errorInit.mBubbles = false;
-    errorInit.mCancelable = true;
-    errorInit.mMessage = aMessage;
-    errorInit.mFilename = aFilename;
-    errorInit.mLineno = aLineNumber;
-    errorInit.mColno = aColumnNumber;
-
-    RefPtr<ErrorEvent> errorEvent =
-      ErrorEvent::Constructor(sharedWorker, NS_LITERAL_STRING("error"),
-                              errorInit);
-    if (!errorEvent) {
+    RefPtr<Event> event;
+
+    if (aIsErrorEvent) {
+      RootedDictionary<ErrorEventInit> errorInit(aCx);
+      errorInit.mBubbles = false;
+      errorInit.mCancelable = true;
+      errorInit.mMessage = aMessage;
+      errorInit.mFilename = aFilename;
+      errorInit.mLineno = aLineNumber;
+      errorInit.mColno = aColumnNumber;
+
+      event = ErrorEvent::Constructor(sharedWorker, NS_LITERAL_STRING("error"),
+                                      errorInit);
+    } else {
+      event = Event::Constructor(sharedWorker, NS_LITERAL_STRING("error"),
+                                 EventInit());
+    }
+
+    if (!event) {
       ThrowAndReport(window, NS_ERROR_UNEXPECTED);
       continue;
     }
 
-    errorEvent->SetTrusted(true);
+    event->SetTrusted(true);
 
     bool defaultActionEnabled;
-    nsresult rv = sharedWorker->DispatchEvent(errorEvent, &defaultActionEnabled);
+    nsresult rv = sharedWorker->DispatchEvent(event, &defaultActionEnabled);
     if (NS_FAILED(rv)) {
       ThrowAndReport(window, rv);
       continue;
     }
 
+    if (!aIsErrorEvent) {
+      continue;
+    }
+
     if (defaultActionEnabled) {
       // Add the owning window to our list so that we will fire an error event
       // at it later.
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index 8008f30e54..465c0f9a33 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -408,7 +408,8 @@ public:
                                 const nsAString& aLine,
                                 uint32_t aLineNumber,
                                 uint32_t aColumnNumber,
-                                uint32_t aFlags);
+                                uint32_t aFlags,
+                                bool aIsErrorEvent);
 
   void
   WorkerScriptLoaded();