Bug 1289318 - Part 1: Store contents of spec-defined `capabilities` struct in Promise reaction jobs directly. r=efaust

No need to keep create an additional object for this.

MozReview-Commit-ID: Hj8kpaBe6fL

js/src/builtin/Promise.cpp

@@ -267,20 +267,13 @@ PromiseObject::dependentPromises(JSContext* cx, MutableHandle<GCVector<Value>> v
     if (!values.growBy(keys.length()))
         return false;
 
-    RootedAtom capabilitiesAtom(cx, Atomize(cx, "capabilities", strlen("capabilities")));
-    if (!capabilitiesAtom)
-        return false;
-    RootedId capabilitiesId(cx, AtomToId(capabilitiesAtom));
-
     // Each reaction is an internally-created object with the structure:
     // {
-    //   capabilities: {
-    //     promise: [the promise this reaction resolves],
-    //     resolve: [the `resolve` callback content code provided],
-    //     reject:  [the `reject` callback content code provided],
-    //    },
-    //    handler: [the internal handler that fulfills/rejects the promise]
-    //  }
+    //   promise: [the promise this reaction resolves],
+    //   resolve: [the `resolve` callback content code provided],
+    //   reject:  [the `reject` callback content code provided],
+    //   handler: [the internal handler that fulfills/rejects the promise]
+    // }
     //
     // In the following loop we collect the `capabilities.promise` values for
     // each reaction.
@@ -289,10 +282,7 @@ PromiseObject::dependentPromises(JSContext* cx, MutableHandle<GCVector<Value>> v
         if (!GetProperty(cx, rejectReactions, rejectReactions, keys[i], val))
             return false;
         RootedObject reaction(cx, &val.toObject());
-        if (!GetProperty(cx, reaction, reaction, capabilitiesId, val))
-            return false;
-        RootedObject capabilities(cx, &val.toObject());
-        if (!GetProperty(cx, capabilities, capabilities, cx->runtime()->commonNames->promise, val))
+        if (!GetProperty(cx, reaction, reaction, cx->runtime()->commonNames->promise, val))
             return false;
     }
 

js/src/builtin/Promise.js

@@ -226,12 +226,11 @@ function TriggerPromiseReactions(reactions, argument) {
 
 // ES6, 25.4.2.1.
 function EnqueuePromiseReactionJob(reaction, argument) {
-    let capabilities = reaction.capabilities;
     _EnqueuePromiseReactionJob(reaction.handler,
                                argument,
-                               capabilities.resolve,
-                               capabilities.reject,
-                               capabilities.promise,
+                               reaction.resolve,
+                               reaction.reject,
+                               reaction.promise,
                                reaction.incumbentGlobal || null);
 }
 
@@ -650,12 +649,9 @@ function AddPromiseReaction(slot, dependentPromise, onResolve, onReject, handler
     }
     _DefineDataProperty(reactions, reactions.length, {
                             __proto__: PromiseReactionRecordProto,
-                            capabilities: {
-                                __proto__: PromiseCapabilityRecordProto,
-                                promise: dependentPromise,
-                                reject: onReject,
-                                resolve: onResolve
-                            },
+                            promise: dependentPromise,
+                            reject: onReject,
+                            resolve: onResolve,
                             handler: handler
                         });
 }
@@ -753,9 +749,9 @@ function Promise_then(onFulfilled, onRejected) {
  *
  * Used internally to implement DOM functionality.
  *
- * Note: the reactions pushed using this function contain a `capabilities`
- * object whose `promise` field can contain null. That field is only ever used
- * by devtools, which have to treat these reactions specially.
+ * Note: the reactions pushed using this function contain a `promise` field
+ * that can contain null. That field is only ever used by devtools, which have
+ * to treat these reactions specially.
  */
 function EnqueuePromiseReactions(promise, dependentPromise, onFulfilled, onRejected) {
     let isWrappedPromise = false;
@@ -891,7 +887,9 @@ function PerformPromiseThen(promise, onFulfilled, onRejected, resultCapability)
     // Step 5.
     let fulfillReaction = {
         __proto__: PromiseReactionRecordProto,
-        capabilities: resultCapability,
+        resolve: resultCapability.resolve,
+        reject: resultCapability.reject,
+        promise: resultCapability.promise,
         handler: onFulfilled,
         incumbentGlobal
     };
@@ -899,7 +897,9 @@ function PerformPromiseThen(promise, onFulfilled, onRejected, resultCapability)
     // Step 6.
     let rejectReaction = {
         __proto__: PromiseReactionRecordProto,
-        capabilities: resultCapability,
+        resolve: resultCapability.resolve,
+        reject: resultCapability.reject,
+        promise: resultCapability.promise,
         handler: onRejected,
         incumbentGlobal
     };