Bug 1016560. Remove the footgun of rejecting promises with arbitrary objects. r=khuey

dom/base/Navigator.cpp

@@ -1497,7 +1497,7 @@ Navigator::GetFeature(const nsAString& aName)
     if (XRE_GetProcessType() == GeckoProcessType_Default) {
       uint32_t memLevel = mozilla::hal::GetTotalSystemMemoryLevel();
       if (memLevel == 0) {
-        p->MaybeReject(NS_LITERAL_STRING("Abnormal"));
+        p->MaybeReject(NS_ERROR_NOT_AVAILABLE);
         return p.forget();
       }
       p->MaybeResolve((int)memLevel);

dom/datastore/DataStoreService.cpp

@@ -150,7 +150,7 @@ RejectPromise(nsPIDOMWindow* aWindow, Promise* aPromise, nsresult aRv)
                          NS_LITERAL_STRING("An error occurred"));
   }
 
-  aPromise->MaybeReject(error);
+  aPromise->MaybeRejectBrokenly(error);
 }
 
 void

dom/filesystem/CreateDirectoryTask.cpp

@@ -122,7 +122,7 @@ CreateDirectoryTask::HandlerCallback()
   if (HasError()) {
     nsRefPtr<DOMError> domError = new DOMError(mFileSystem->GetWindow(),
       mErrorValue);
-    mPromise->MaybeReject(domError);
+    mPromise->MaybeRejectBrokenly(domError);
     mPromise = nullptr;
     return;
   }

dom/filesystem/CreateFileTask.cpp

@@ -287,7 +287,7 @@ CreateFileTask::HandlerCallback()
   if (HasError()) {
     nsRefPtr<DOMError> domError = new DOMError(mFileSystem->GetWindow(),
       mErrorValue);
-    mPromise->MaybeReject(domError);
+    mPromise->MaybeRejectBrokenly(domError);
     mPromise = nullptr;
     return;
   }

dom/filesystem/GetFileOrDirectoryTask.cpp

@@ -197,7 +197,7 @@ GetFileOrDirectoryTask::HandlerCallback()
   if (HasError()) {
     nsRefPtr<DOMError> domError = new DOMError(mFileSystem->GetWindow(),
       mErrorValue);
-    mPromise->MaybeReject(domError);
+    mPromise->MaybeRejectBrokenly(domError);
     mPromise = nullptr;
     return;
   }

dom/filesystem/RemoveTask.cpp

@@ -185,7 +185,7 @@ RemoveTask::HandlerCallback()
   if (HasError()) {
     nsRefPtr<DOMError> domError = new DOMError(mFileSystem->GetWindow(),
       mErrorValue);
-    mPromise->MaybeReject(domError);
+    mPromise->MaybeRejectBrokenly(domError);
     mPromise = nullptr;
     return;
   }

dom/ipc/ContentChild.cpp

@@ -1473,7 +1473,7 @@ ContentChild::RecvSystemMemoryAvailable(const uint64_t& aGetterId,
     nsRefPtr<Promise> p = dont_AddRef(reinterpret_cast<Promise*>(aGetterId));
 
     if (!aMemoryAvailable) {
-        p->MaybeReject(NS_LITERAL_STRING("Abnormal"));
+        p->MaybeReject(NS_ERROR_NOT_AVAILABLE);
         return true;
     }
 

dom/promise/Promise.cpp

@@ -7,6 +7,7 @@
 #include "mozilla/dom/Promise.h"
 
 #include "jsfriendapi.h"
+#include "mozilla/dom/DOMError.h"
 #include "mozilla/dom/OwningNonNull.h"
 #include "mozilla/dom/PromiseBinding.h"
 #include "mozilla/CycleCollectedJSRuntime.h"
@@ -1431,5 +1432,15 @@ PromiseWorkerProxy::CleanUp(JSContext* aCx)
   mCleanedUp = true;
 }
 
+// Specializations of MaybeRejectBrokenly we actually support.
+template<>
+void Promise::MaybeRejectBrokenly(const nsRefPtr<DOMError>& aArg) {
+  MaybeSomething(aArg, &Promise::MaybeReject);
+}
+template<>
+void Promise::MaybeRejectBrokenly(const nsAString& aArg) {
+  MaybeSomething(aArg, &Promise::MaybeReject);
+}
+
 } // namespace dom
 } // namespace mozilla

dom/promise/Promise.h

@@ -26,6 +26,7 @@ namespace mozilla {
 namespace dom {
 
 class AnyCallback;
+class DOMError;
 class PromiseCallback;
 class PromiseInit;
 class PromiseNativeHandler;
@@ -89,11 +90,21 @@ public:
     MaybeSomething(aArg, &Promise::MaybeResolve);
   }
 
-  // aArg is a const reference so we can pass rvalues like NS_ERROR_*
-  template <typename T>
-  void MaybeReject(const T& aArg) {
+  inline void MaybeReject(nsresult aArg) {
+    MOZ_ASSERT(NS_FAILED(aArg));
     MaybeSomething(aArg, &Promise::MaybeReject);
   }
+  // DO NOT USE MaybeRejectBrokenly with in new code.  Promises should be
+  // rejected with Error instances.
+  // Note: MaybeRejectBrokenly is a template so we can use it with DOMError
+  // without instantiating the DOMError specialization of MaybeSomething in
+  // every translation unit that includes this header, because that would
+  // require use to include DOMError.h either here or in all those translation
+  // units.
+  template<typename T>
+  void MaybeRejectBrokenly(const T& aArg); // Not implemented by default; see
+                                           // specializations in the .cpp for
+                                           // the T values we support.
 
   // WebIDL
 

dom/telephony/Telephony.cpp

@@ -76,7 +76,7 @@ public:
   NS_IMETHODIMP
   NotifyDialError(const nsAString& aError)
   {
-    mPromise->MaybeReject(aError);
+    mPromise->MaybeRejectBrokenly(aError);
     return NS_OK;
   }
 
@@ -255,13 +255,13 @@ Telephony::DialInternal(uint32_t aServiceId, const nsAString& aNumber,
   nsRefPtr<Promise> promise = new Promise(global);
 
   if (!IsValidNumber(aNumber) || !IsValidServiceId(aServiceId)) {
-    promise->MaybeReject(NS_LITERAL_STRING("InvalidAccessError"));
+    promise->MaybeReject(NS_ERROR_DOM_INVALID_ACCESS_ERR);
     return promise.forget();
   }
 
   // We only support one outgoing call at a time.
   if (HasDialingCall()) {
-    promise->MaybeReject(NS_LITERAL_STRING("InvalidStateError"));
+    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
     return promise.forget();
   }
 
@@ -269,7 +269,7 @@ Telephony::DialInternal(uint32_t aServiceId, const nsAString& aNumber,
     new Callback(this, promise, aServiceId, aNumber);
   nsresult rv = mService->Dial(aServiceId, aNumber, aIsEmergency, callback);
   if (NS_FAILED(rv)) {
-    promise->MaybeReject(NS_LITERAL_STRING("InvalidStateError"));
+    promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR);
     return promise.forget();
   }