From 3b4a81565780b724841c2950513416f14ab95ff3 Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@mit.edu>
Date: Thu, 12 Apr 2018 23:26:44 -0400
Subject: Bug 1453339 - Make it harder to mess up Promise::All. r=peterv,
 a=RyanVM

MozReview-Commit-ID: UO4wssYHj7
---
 dom/promise/Promise.cpp | 27 +++++++++++++++------------
 dom/promise/Promise.h   | 19 +++++++++++--------
 2 files changed, 26 insertions(+), 20 deletions(-)

(limited to 'dom/promise')

diff --git a/dom/promise/Promise.cpp b/dom/promise/Promise.cpp
index 00b78143e..557f3a1f9 100644
--- a/dom/promise/Promise.cpp
+++ b/dom/promise/Promise.cpp
@@ -561,37 +561,40 @@ Promise::Reject(nsIGlobalObject* aGlobal, JSContext* aCx,
 
 // static
 already_AddRefed<Promise>
-Promise::All(const GlobalObject& aGlobal,
+Promise::All(JSContext* aCx,
              const nsTArray<RefPtr<Promise>>& aPromiseList, ErrorResult& aRv)
 {
-  nsCOMPtr<nsIGlobalObject> global;
-  global = do_QueryInterface(aGlobal.GetAsSupports());
-  if (!global) {
+  JS::Rooted<JSObject*> globalObj(aCx, JS::CurrentGlobalOrNull(aCx));
+  if (!globalObj) {
     aRv.Throw(NS_ERROR_UNEXPECTED);
     return nullptr;
   }
 
-  JSContext* cx = aGlobal.Context();
+  nsCOMPtr<nsIGlobalObject> global = xpc::NativeGlobal(globalObj);
+  if (!global) {
+    aRv.Throw(NS_ERROR_UNEXPECTED);
+    return nullptr;
+  }
 
-  JS::AutoObjectVector promises(cx);
+  JS::AutoObjectVector promises(aCx);
   if (!promises.reserve(aPromiseList.Length())) {
-    aRv.NoteJSContextException(cx);
+    aRv.NoteJSContextException(aCx);
     return nullptr;
   }
 
   for (auto& promise : aPromiseList) {
-    JS::Rooted<JSObject*> promiseObj(cx, promise->PromiseObj());
+    JS::Rooted<JSObject*> promiseObj(aCx, promise->PromiseObj());
     // Just in case, make sure these are all in the context compartment.
-    if (!JS_WrapObject(cx, &promiseObj)) {
-      aRv.NoteJSContextException(cx);
+    if (!JS_WrapObject(aCx, &promiseObj)) {
+      aRv.NoteJSContextException(aCx);
       return nullptr;
     }
     promises.infallibleAppend(promiseObj);
   }
 
-  JS::Rooted<JSObject*> result(cx, JS::GetWaitForAllPromise(cx, promises));
+  JS::Rooted<JSObject*> result(aCx, JS::GetWaitForAllPromise(aCx, promises));
   if (!result) {
-    aRv.NoteJSContextException(cx);
+    aRv.NoteJSContextException(aCx);
     return nullptr;
   }
 
diff --git a/dom/promise/Promise.h b/dom/promise/Promise.h
index f2ad3bd6c..642603a11 100644
--- a/dom/promise/Promise.h
+++ b/dom/promise/Promise.h
@@ -188,23 +188,26 @@ public:
   WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto,
              JS::MutableHandle<JSObject*> aWrapper);
 
-  // Do the equivalent of Promise.resolve in the current compartment of aCx.
-  // Errorrs are reported on the ErrorResult; if aRv comes back !Failed(), this
-  // function MUST return a non-null value.
+  // Do the equivalent of Promise.resolve in the compartment of aGlobal.  The
+  // compartment of aCx is ignored.  Errors are reported on the ErrorResult; if
+  // aRv comes back !Failed(), this function MUST return a non-null value.
   static already_AddRefed<Promise>
   Resolve(nsIGlobalObject* aGlobal, JSContext* aCx,
           JS::Handle<JS::Value> aValue, ErrorResult& aRv);
 
-  // Do the equivalent of Promise.reject in the current compartment of aCx.
-  // Errorrs are reported on the ErrorResult; if aRv comes back !Failed(), this
-  // function MUST return a non-null value.
+  // Do the equivalent of Promise.reject in the compartment of aGlobal.  The
+  // compartment of aCx is ignored.  Errors are reported on the ErrorResult; if
+  // aRv comes back !Failed(), this function MUST return a non-null value.
   static already_AddRefed<Promise>
   Reject(nsIGlobalObject* aGlobal, JSContext* aCx,
          JS::Handle<JS::Value> aValue, ErrorResult& aRv);
 
+  // Do the equivalent of Promise.all in the current compartment of aCx.  Errors
+  // are reported on the ErrorResult; if aRv comes back !Failed(), this function
+  // MUST return a non-null value.
   static already_AddRefed<Promise>
-  All(const GlobalObject& aGlobal,
-      const nsTArray<RefPtr<Promise>>& aPromiseList, ErrorResult& aRv);
+  All(JSContext* aCx, const nsTArray<RefPtr<Promise>>& aPromiseList,
+      ErrorResult& aRv);
 
   void
   Then(JSContext* aCx,
-- 
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