1 files changed, 60 insertions, 37 deletions

diff --git a/dom/base/ScriptSettings.cpp b/dom/base/ScriptSettings.cpp
index 3fbfb9043..daf8ebb33 100644
--- a/dom/base/ScriptSettings.cpp
+++ b/dom/base/ScriptSettings.cpp
@@ -312,36 +312,15 @@ AutoJSAPI::~AutoJSAPI()
 {
   if (mOwnErrorReporting) {
     MOZ_ASSERT(NS_IsMainThread(), "See corresponding assertion in TakeOwnershipOfErrorReporting()");
-    JS::ContextOptionsRef(cx()).setAutoJSAPIOwnsErrorReporting(mOldAutoJSAPIOwnsErrorReporting);
 
-    if (HasException()) {
-
-      // AutoJSAPI uses a JSAutoNullableCompartment, and may be in a null
-      // compartment when the destructor is called. However, the JS engine
-      // requires us to be in a compartment when we fetch the pending exception.
-      // In this case, we enter the privileged junk scope and don't dispatch any
-      // error events.
-      JS::Rooted<JSObject*> errorGlobal(cx(), JS::CurrentGlobalOrNull(cx()));
-      if (!errorGlobal)
-        errorGlobal = xpc::PrivilegedJunkScope();
-      JSAutoCompartment ac(cx(), errorGlobal);
-      nsCOMPtr<nsPIDOMWindow> win = xpc::WindowGlobalOrNull(errorGlobal);
-      JS::Rooted<JS::Value> exn(cx());
-      js::ErrorReport jsReport(cx());
-      if (StealException(&exn) && jsReport.init(cx(), exn)) {
-        nsRefPtr<xpc::ErrorReport> xpcReport = new xpc::ErrorReport();
-        xpcReport->Init(jsReport.report(), jsReport.message(),
-                        nsContentUtils::IsCallerChrome(),
-                        win ? win->WindowID() : 0);
-        if (win) {
-          DispatchScriptErrorEvent(win, JS_GetRuntime(cx()), xpcReport, exn);
-        } else {
-          xpcReport->LogToConsole();
-        }
-      } else {
-        NS_WARNING("OOMed while acquiring uncaught exception from JSAPI");
-      }
-    }
+    ReportException();
+
+    // We need to do this _after_ processing the existing exception, because the
+    // JS engine can throw while doing that, and uses this bit to determine what
+    // to do in that case: squelch the exception if the bit is set, otherwise
+    // call the error reporter. Calling WarningOnlyErrorReporter with a
+    // non-warning will assert, so we need to make sure we do the former.
+    JS::ContextOptionsRef(cx()).setAutoJSAPIOwnsErrorReporting(mOldAutoJSAPIOwnsErrorReporting);
   }
 
   if (mOldErrorReporter.isSome()) {
@@ -502,17 +481,61 @@ AutoJSAPI::TakeOwnershipOfErrorReporting()
   JS_SetErrorReporter(rt, WarningOnlyErrorReporter);
 }
 
+void
+AutoJSAPI::ReportException()
+{
+  MOZ_ASSERT(OwnsErrorReporting(), "This is not our exception to report!");
+  if (!HasException()) {
+    return;
+  }
+
+  // AutoJSAPI uses a JSAutoNullableCompartment, and may be in a null
+  // compartment when the destructor is called. However, the JS engine
+  // requires us to be in a compartment when we fetch the pending exception.
+  // In this case, we enter the privileged junk scope and don't dispatch any
+  // error events.
+  JS::Rooted<JSObject*> errorGlobal(cx(), JS::CurrentGlobalOrNull(cx()));
+  if (!errorGlobal)
+    errorGlobal = xpc::PrivilegedJunkScope();
+  JSAutoCompartment ac(cx(), errorGlobal);
+  nsCOMPtr<nsPIDOMWindow> win = xpc::WindowGlobalOrNull(errorGlobal);
+  JS::Rooted<JS::Value> exn(cx());
+  js::ErrorReport jsReport(cx());
+  if (StealException(&exn) && jsReport.init(cx(), exn)) {
+    nsRefPtr<xpc::ErrorReport> xpcReport = new xpc::ErrorReport();
+    xpcReport->Init(jsReport.report(), jsReport.message(),
+                    nsContentUtils::IsCallerChrome(),
+                    win ? win->WindowID() : 0);
+    if (win) {
+      DispatchScriptErrorEvent(win, JS_GetRuntime(cx()), xpcReport, exn);
+    } else {
+      xpcReport->LogToConsole();
+    }
+  } else {
+    NS_WARNING("OOMed while acquiring uncaught exception from JSAPI");
+  }
+}
+
+bool
+AutoJSAPI::PeekException(JS::MutableHandle<JS::Value> aVal)
+{
+  MOZ_ASSERT_IF(mIsMainThread, CxPusherIsStackTop());
+  MOZ_ASSERT(HasException());
+  MOZ_ASSERT(js::GetContextCompartment(cx()));
+  if (!JS_GetPendingException(cx(), aVal)) {
+    return false;
+  }
+  return true;
+}
+
 bool
 AutoJSAPI::StealException(JS::MutableHandle<JS::Value> aVal)
 {
-    MOZ_ASSERT(CxPusherIsStackTop());
-    MOZ_ASSERT(HasException());
-    MOZ_ASSERT(js::GetContextCompartment(cx()));
-    if (!JS_GetPendingException(cx(), aVal)) {
-      return false;
-    }
-    JS_ClearPendingException(cx());
-    return true;
+  if (!PeekException(aVal)) {
+    return false;
+  }
+  JS_ClearPendingException(cx());
+  return true;
 }
 
 AutoEntryScript::AutoEntryScript(nsIGlobalObject* aGlobalObject,