Object.observe: Change semantics of deliverChangeRecords to iterate.

src/object-observe.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 64 matching lines @@
     throw MakeTypeError("observe_callback_frozen");
 
   if (!observerInfoMap.has(callback)) {
     observerInfoMap.set(callback, {
       pendingChangeRecords: null,
       priority: observationState.observerPriority++,
     });
   }
 
   var objectInfo = objectInfoMap.get(object);
-  if (IS_UNDEFINED(objectInfo)) {
-    objectInfo = CreateObjectInfo(object);
-  }
+  if (IS_UNDEFINED(objectInfo)) objectInfo = CreateObjectInfo(object);
   %SetIsObserved(object, true);
 
   var changeObservers = objectInfo.changeObservers;
-  if (changeObservers.indexOf(callback) < 0)
-    changeObservers.push(callback);
+  if (changeObservers.indexOf(callback) < 0) changeObservers.push(callback);
 
   return object;
 }
 
 function ObjectUnobserve(object, callback) {
   if (!IS_SPEC_OBJECT(object))
     throw MakeTypeError("observe_non_object", ["unobserve"]);
   if (!IS_SPEC_FUNCTION(callback))
     throw MakeTypeError("observe_non_function", ["unobserve"]);
 
   var objectInfo = objectInfoMap.get(object);
   if (IS_UNDEFINED(objectInfo))
     return object;
 
   var changeObservers = objectInfo.changeObservers;
   var index = changeObservers.indexOf(callback);
   if (index >= 0) {
     changeObservers.splice(index, 1);
-    if (changeObservers.length === 0)
-      %SetIsObserved(object, false);
+    if (changeObservers.length === 0) %SetIsObserved(object, false);
   }
 
   return object;
 }
 
 function EnqueueChangeRecord(changeRecord, observers) {
   for (var i = 0; i < observers.length; i++) {
     var observer = observers[i];
     var observerInfo = observerInfoMap.get(observer);
     observationState.pendingObservers[observerInfo.priority] = observer;
@@ skipping 11 matching lines @@
   var changeRecord = (arguments.length < 4) ?
       { type: type, object: object, name: name } :
       { type: type, object: object, name: name, oldValue: oldValue };
   ObjectFreeze(changeRecord);
   EnqueueChangeRecord(changeRecord, objectInfo.changeObservers);
 }
 
 var notifierPrototype = {};
 
 function ObjectNotifierNotify(changeRecord) {
+  var target = notifierTargetMap.get(this);
   if (!IS_SPEC_OBJECT(this))
     throw MakeTypeError("called_on_non_object", ["notify"]);
-
-  var target = notifierTargetMap.get(this);
   if (IS_UNDEFINED(target))
     throw MakeTypeError("observe_notify_non_notifier");
-
   if (!IS_STRING(changeRecord.type))
     throw MakeTypeError("observe_type_non_string");
 
   var objectInfo = objectInfoMap.get(target);
-  if (IS_UNDEFINED(objectInfo))
+  if (IS_UNDEFINED(objectInfo) || objectInfo.changeObservers.length === 0)
     return;
 
-  if (!objectInfo.changeObservers.length)
-    return;
-
-  var newRecord = {
-    object: target
-  };
+  var newRecord = { object: target };
   for (var prop in changeRecord) {
-    if (prop === 'object')
-      continue;
-
+    if (prop === 'object') continue;
     %DefineOrRedefineDataProperty(newRecord, prop, changeRecord[prop],
         READ_ONLY + DONT_DELETE);
   }
   ObjectFreeze(newRecord);
 
   EnqueueChangeRecord(newRecord, objectInfo.changeObservers);
 }
 
 function ObjectGetNotifier(object) {
   if (!IS_SPEC_OBJECT(object))
     throw MakeTypeError("observe_non_object", ["getNotifier"]);
 
-  if (ObjectIsFrozen(object))
-    return null;
+  if (ObjectIsFrozen(object)) return null;
 
   var objectInfo = objectInfoMap.get(object);
-  if (IS_UNDEFINED(objectInfo))
-    objectInfo = CreateObjectInfo(object);
+  if (IS_UNDEFINED(objectInfo)) objectInfo = CreateObjectInfo(object);
 
   if (IS_NULL(objectInfo.notifier)) {
-    objectInfo.notifier = {
-      __proto__: notifierPrototype
-    };
+    objectInfo.notifier = { __proto__: notifierPrototype };
     notifierTargetMap.set(objectInfo.notifier, object);
   }
 
   return objectInfo.notifier;
 }
 
 function DeliverChangeRecordsForObserver(observer) {
   var observerInfo = observerInfoMap.get(observer);
   if (IS_UNDEFINED(observerInfo))
-    return;
+    return false;
 
   var pendingChangeRecords = observerInfo.pendingChangeRecords;
   if (IS_NULL(pendingChangeRecords))
-    return;
+    return false;
 
   observerInfo.pendingChangeRecords = null;
   delete observationState.pendingObservers[observerInfo.priority];
   var delivered = [];
   %MoveArrayContents(pendingChangeRecords, delivered);
   try {
     %Call(void 0, delivered, observer);
   } catch (ex) {}
+  return true;
 }
 
 function ObjectDeliverChangeRecords(callback) {
   if (!IS_SPEC_FUNCTION(callback))
     throw MakeTypeError("observe_non_function", ["deliverChangeRecords"]);
 
-  DeliverChangeRecordsForObserver(callback);
+  while (DeliverChangeRecordsForObserver(callback)) {}
 }
 
 function DeliverChangeRecords() {
   while (observationState.pendingObservers.length) {
     var pendingObservers = observationState.pendingObservers;
     observationState.pendingObservers = new InternalArray;
     for (var i in pendingObservers) {
       DeliverChangeRecordsForObserver(pendingObservers[i]);
     }
   }
 }
 
 function SetupObjectObserve() {
   %CheckIsBootstrapping();
   InstallFunctions($Object, DONT_ENUM, $Array(
     "deliverChangeRecords", ObjectDeliverChangeRecords,
     "getNotifier", ObjectGetNotifier,
     "observe", ObjectObserve,
     "unobserve", ObjectUnobserve
   ));
   InstallFunctions(notifierPrototype, DONT_ENUM, $Array(
     "notify", ObjectNotifierNotify
   ));
 }
 
 SetupObjectObserve();