From 0bbce93c83d3f73f91ee6e8cb8906b9884715db1 Mon Sep 17 00:00:00 2001
From: Boris Zbarsky <bzbarsky@mit.edu>
Date: Wed, 25 Nov 2015 15:48:09 -0500
Subject: [PATCH] Bug 1170760 part 11.  Add subclassing support to
 Promise::Reject.  r=baku,efaust

---
 browser/base/content/sync/aboutSyncTabs.js    |  2 +-
 dom/promise/Promise.cpp                       | 48 ++++++++++++++++---
 dom/promise/Promise.h                         |  5 +-
 dom/promise/tests/test_bug883683.html         |  2 +-
 dom/promise/tests/test_promise_xrays.html     | 14 ++++++
 dom/webidl/Promise.webidl                     |  4 +-
 services/cloudsync/CloudSyncBookmarks.jsm     | 12 ++---
 .../js/builtins/Promise-subclassing.html      | 11 +++++
 8 files changed, 79 insertions(+), 19 deletions(-)

diff --git a/browser/base/content/sync/aboutSyncTabs.js b/browser/base/content/sync/aboutSyncTabs.js
index 01057047f9b8..afaa5db3bd5b 100644
--- a/browser/base/content/sync/aboutSyncTabs.js
+++ b/browser/base/content/sync/aboutSyncTabs.js
@@ -273,7 +273,7 @@ var RemoteTabViewer = {
     }.bind(this);
 
     return CloudSync().tabs.getRemoteTabs()
-                           .then(updateTabList, Promise.reject);
+                           .then(updateTabList, Promise.reject.bind(Promise));
   },
 
   adjustContextMenu: function (event) {
diff --git a/dom/promise/Promise.cpp b/dom/promise/Promise.cpp
index c54cfd7520cd..6b199af795e0 100644
--- a/dom/promise/Promise.cpp
+++ b/dom/promise/Promise.cpp
@@ -1092,22 +1092,56 @@ Promise::Resolve(nsIGlobalObject* aGlobal, JSContext* aCx,
   return promise.forget();
 }
 
-/* static */ already_AddRefed<Promise>
+/* static */ void
 Promise::Reject(const GlobalObject& aGlobal, JS::Handle<JS::Value> aThisv,
-                JS::Handle<JS::Value> aValue, ErrorResult& aRv)
+                JS::Handle<JS::Value> aValue,
+                JS::MutableHandle<JS::Value> aRetval, ErrorResult& aRv)
 {
+  // Implementation of
+  // http://www.ecma-international.org/ecma-262/6.0/#sec-promise.reject
+
+  JSContext* cx = aGlobal.Context();
+
   nsCOMPtr<nsIGlobalObject> global =
     do_QueryInterface(aGlobal.GetAsSupports());
   if (!global) {
     aRv.Throw(NS_ERROR_UNEXPECTED);
-    return nullptr;
+    return;
   }
 
-  RefPtr<Promise> p = Reject(global, aGlobal.Context(), aValue, aRv);
-  if (p) {
-    p->mRejectionStack = p->mAllocationStack;
+  // Steps 1 and 2.
+  if (!aThisv.isObject()) {
+    aRv.ThrowTypeError<MSG_ILLEGAL_PROMISE_CONSTRUCTOR>();
+    return;
   }
-  return p.forget();
+
+  // Step 3.
+  PromiseCapability capability(cx);
+  NewPromiseCapability(cx, global, aThisv, false, capability, aRv);
+  // Step 4.
+  if (aRv.Failed()) {
+    return;
+  }
+
+  // Step 5.
+  Promise* p = capability.mNativePromise;
+  if (p) {
+    p->MaybeRejectInternal(cx, aValue);
+    p->mRejectionStack = p->mAllocationStack;
+  } else {
+    JS::Rooted<JS::Value> value(cx, aValue);
+    JS::Rooted<JS::Value> ignored(cx);
+    if (!JS::Call(cx, JS::UndefinedHandleValue /* thisVal */,
+                  capability.mReject, JS::HandleValueArray(value),
+                  &ignored)) {
+      // Step 6.
+      aRv.NoteJSContextException();
+      return;
+    }
+  }
+
+  // Step 7.
+  aRetval.set(capability.PromiseValue());
 }
 
 /* static */ already_AddRefed<Promise>
diff --git a/dom/promise/Promise.h b/dom/promise/Promise.h
index 40a95286865b..5e7a371c0c80 100644
--- a/dom/promise/Promise.h
+++ b/dom/promise/Promise.h
@@ -172,9 +172,10 @@ public:
   Resolve(nsIGlobalObject* aGlobal, JSContext* aCx,
           JS::Handle<JS::Value> aValue, ErrorResult& aRv);
 
-  static already_AddRefed<Promise>
+  static void
   Reject(const GlobalObject& aGlobal, JS::Handle<JS::Value> aThisv,
-         JS::Handle<JS::Value> aValue, ErrorResult& aRv);
+         JS::Handle<JS::Value> aValue,
+         JS::MutableHandle<JS::Value> aRetval, ErrorResult& aRv);
 
   static already_AddRefed<Promise>
   Reject(nsIGlobalObject* aGlobal, JSContext* aCx,
diff --git a/dom/promise/tests/test_bug883683.html b/dom/promise/tests/test_bug883683.html
index 866fdd6a5df9..ab23ca10d462 100644
--- a/dom/promise/tests/test_bug883683.html
+++ b/dom/promise/tests/test_bug883683.html
@@ -17,7 +17,7 @@
 <script type="application/javascript"><!--
 
 function runTest() {
-  [{}, {}, {}, {}, {}].reduce(Promise.reject);
+  [{}, {}, {}, {}, {}].reduce(Promise.reject.bind(Promise));
   ok(true, "No leaks with reject?");
 
   [{}, {}, {}, {}, {}].reduce(Promise.resolve.bind(Promise));
diff --git a/dom/promise/tests/test_promise_xrays.html b/dom/promise/tests/test_promise_xrays.html
index 601e8f4e9996..e04d705bc9f5 100644
--- a/dom/promise/tests/test_promise_xrays.html
+++ b/dom/promise/tests/test_promise_xrays.html
@@ -205,6 +205,19 @@ function testResolve3() {
   ).then(nextTest);
 }
 
+function testReject1() {
+  var p = win.Promise.reject(5);
+  ok(p instanceof win.Promise, "Promise.reject should return a promise");
+  p.then(
+    function(arg) {
+      ok(false, "Promise should be rejected");
+    },
+    function(e) {
+      is(e, 5, "Should get correct Promise.reject value");
+    }
+  ).then(nextTest);
+}
+
 var tests = [
   testLoadComplete,
   testHaveXray,
@@ -220,6 +233,7 @@ var tests = [
   testResolve1,
   testResolve2,
   testResolve3,
+  testReject1,
 ];
 
 function nextTest() {
diff --git a/dom/webidl/Promise.webidl b/dom/webidl/Promise.webidl
index 70221b40ab2f..b14d9c3a33df 100644
--- a/dom/webidl/Promise.webidl
+++ b/dom/webidl/Promise.webidl
@@ -25,8 +25,8 @@ interface _Promise {
   // return value of PromiseSubclass.resolve/reject to be a Promise object.
   [NewObject, Throws]
   static any resolve(optional any value);
-  [NewObject]
-  static Promise<void> reject(optional any value);
+  [NewObject, Throws]
+  static any reject(optional any value);
 
   // The [TreatNonCallableAsNull] annotation is required since then() should do
   // nothing instead of throwing errors when non-callable arguments are passed.
diff --git a/services/cloudsync/CloudSyncBookmarks.jsm b/services/cloudsync/CloudSyncBookmarks.jsm
index c3c8efbd9b96..bb2e48d59828 100644
--- a/services/cloudsync/CloudSyncBookmarks.jsm
+++ b/services/cloudsync/CloudSyncBookmarks.jsm
@@ -294,7 +294,7 @@ var RootFolder = function (rootId, rootName) {
             result.parent = guidResult;
             return Promise.resolve(result);
           },
-          Promise.reject
+          Promise.reject.bind(Promise)
         );
         promises.push(promise);
       });
@@ -310,7 +310,7 @@ var RootFolder = function (rootId, rootName) {
             result.annos = annos;
             return Promise.resolve(result);
           },
-          Promise.reject
+          Promise.reject.bind(Promise)
         );
         promises.push(promise);
       });
@@ -352,7 +352,7 @@ var RootFolder = function (rootId, rootName) {
             result.parent = guidResult;
             return Promise.resolve(result);
           },
-          Promise.reject
+          Promise.reject.bind(Promise)
         );
         promises.push(promise);
       });
@@ -559,7 +559,7 @@ var RootFolder = function (rootId, rootName) {
           continue;
         }
 
-        let promise = exists(item).then(handleSortedItem, Promise.reject);
+        let promise = exists(item).then(handleSortedItem, Promise.reject.bind(Promise));
         promises.push(promise);
       }
 
@@ -588,7 +588,7 @@ var RootFolder = function (rootId, rootName) {
           function () {
             return _createItem(root);
           },
-          Promise.reject
+          Promise.reject.bind(Promise)
         );
         let items = [].concat(root._children);
 
@@ -599,7 +599,7 @@ var RootFolder = function (rootId, rootName) {
             function () {
               return _createItem(item);
             },
-            Promise.reject
+            Promise.reject.bind(Promise)
           );
         }
         promises.push(promise);
diff --git a/testing/web-platform/tests/js/builtins/Promise-subclassing.html b/testing/web-platform/tests/js/builtins/Promise-subclassing.html
index 5aaa0d7d81b5..b1207edb5294 100644
--- a/testing/web-platform/tests/js/builtins/Promise-subclassing.html
+++ b/testing/web-platform/tests/js/builtins/Promise-subclassing.html
@@ -206,4 +206,15 @@ promise_test(function testPromiseResolve() {
   });
 }, "Promise.resolve behavior");
 
+promise_test(function testPromiseReject() {
+  clearLog();
+  var p = LoggingPromise.reject(5);
+  var log = takeLog();
+  assert_array_equals(log, ["Reject 1", "Constructor 1"]);
+
+  return p.catch(function(arg) {
+    assert_equals(arg, 5);
+  });
+}, "Promise.reject behavior");
+
 </script>