Use weakmap for non internal meta

packages/ember-metal/lib/chains.js

@@ -1,6 +1,6 @@
 import { warn } from 'ember-metal/debug';
 import { get, normalizeTuple } from 'ember-metal/property_get';
-import { meta as metaFor } from 'ember-metal/meta';
+import { meta as metaFor, readMeta } from 'ember-metal/meta';
 import { watchKey, unwatchKey } from 'ember-metal/watch_key';
 import EmptyObject from 'ember-metal/empty_object';
 
@@ -147,7 +147,7 @@ function removeChainWatcher(obj, keyName, node) {
     return;
   }
 
-  let m = obj.__ember_meta__;
+  let m = readMeta(obj);
 
   if (!m || !m.readableChainWatchers()) {
     return;
@@ -195,7 +195,7 @@ function lazyGet(obj, key) {
     return;
   }
 
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
 
   // check if object meant only to be a prototype
   if (meta && meta.proto === obj) {
@@ -401,7 +401,7 @@ ChainNode.prototype = {
 
 export function finishChains(obj) {
   // We only create meta if we really have to
-  let m = obj.__ember_meta__;
+  let m = readMeta(obj);
   if (m) {
     m = metaFor(obj);
 

packages/ember-metal/lib/computed.js

@@ -1,7 +1,7 @@
 import { assert } from 'ember-metal/debug';
 import { set } from 'ember-metal/property_set';
 import { inspect } from 'ember-metal/utils';
-import { meta as metaFor } from 'ember-metal/meta';
+import { meta as metaFor, readMeta } from 'ember-metal/meta';
 import expandProperties from 'ember-metal/expand_properties';
 import EmberError from 'ember-metal/error';
 import {
@@ -313,7 +313,7 @@ ComputedPropertyPrototype.didChange = function(obj, keyName) {
   }
 
   // don't create objects just to invalidate
-  let meta = obj.__ember_meta__;
+  let meta = readMeta(obj);
   if (!meta || meta.source !== obj) {
     return;
   }
@@ -620,7 +620,7 @@ export default function computed(func) {
   @public
 */
 function cacheFor(obj, key) {
-  var meta = obj.__ember_meta__;
+  var meta = readMeta(obj);
   var cache = meta && meta.source === obj && meta.readableCache();
   var ret = cache && cache[key];
 

packages/ember-metal/lib/events.js

@@ -11,7 +11,7 @@ import {
   apply,
   applyStr
 } from 'ember-metal/utils';
-import { meta as metaFor } from 'ember-metal/meta';
+import { meta as metaFor, readMeta } from 'ember-metal/meta';
 
 import { ONCE, SUSPENDED } from 'ember-metal/meta_listeners';
 
@@ -49,7 +49,7 @@ function indexOf(array, target, method) {
 }
 
 export function accumulateListeners(obj, eventName, otherActions) {
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
   if (!meta) { return; }
   var actions = meta.matchingListeners(eventName);
   var newActions = [];
@@ -201,7 +201,7 @@ export function watchedEvents(obj) {
 */
 export function sendEvent(obj, eventName, params, actions) {
   if (!actions) {
-    var meta = obj['__ember_meta__'];
+    var meta = readMeta(obj);
     actions = meta && meta.matchingListeners(eventName);
   }
 
@@ -241,7 +241,7 @@ export function sendEvent(obj, eventName, params, actions) {
   @param {String} eventName
 */
 export function hasListeners(obj, eventName) {
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
   if (!meta) { return false; }
   return meta.matchingListeners(eventName).length > 0;
 }
@@ -255,7 +255,7 @@ export function hasListeners(obj, eventName) {
 */
 export function listenersFor(obj, eventName) {
   var ret = [];
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
   var actions = meta && meta.matchingListeners(eventName);
 
   if (!actions) { return ret; }

packages/ember-metal/lib/meta.js

@@ -298,7 +298,7 @@ var EMBER_META_PROPERTY = {
 
 // Placeholder for non-writable metas.
 export var EMPTY_META = new Meta(null);
-
+var weakMeta = self.WeakMap && new self.WeakMap();
 /**
   Retrieves the meta hash for an object. If `writable` is true ensures the
   hash is writable for this object as well.
@@ -318,7 +318,8 @@ export var EMPTY_META = new Meta(null);
   @return {Object} the meta hash for an object
 */
 export function meta(obj, writable) {
-  var ret = obj.__ember_meta__;
+  var ret = readMeta(obj);
+
   if (writable === false) {
     return ret || EMPTY_META;
   }
@@ -335,14 +336,33 @@ export function meta(obj, writable) {
 
   // if `null` already, just set it to the new value
   // otherwise define property first
-  if (obj.__ember_meta__ !== null) {
+  if (obj.__ember_meta__ === null) {
+    obj.__ember_meta__ = ret;
+  } else if (weakMeta) {
+    weakMeta.set(obj, ret);
+  } else {
     if (obj.__defineNonEnumerable) {
       obj.__defineNonEnumerable(EMBER_META_PROPERTY);
     } else {
       Object.defineProperty(obj, '__ember_meta__', META_DESC);
     }
+    obj.__ember_meta__ = ret;
   }
-  obj.__ember_meta__ = ret;
+
 
   return ret;
 }
+
+export function readMeta(obj) {
+  if (obj.__ember_meta__) {
+    return obj.__ember_meta__;
+  } else if (weakMeta) {
+    return weakMeta.get(obj);
+  }
+}
+
+
+export function deleteMeta(obj) {
+  if (obj.__ember_meta__) { obj.__ember_meta__ = null; }
+  else if (weakMeta)      { weakMeta.delete(obj); }
+}

packages/ember-metal/lib/mixin.js

@@ -37,6 +37,7 @@ import {
   removeListener
 } from 'ember-metal/events';
 import { isStream } from 'ember-metal/streams/utils';
+import { readMeta } from 'ember-metal/meta';
 
 function ROOT() {}
 ROOT.__hasSuper = false;
@@ -604,7 +605,7 @@ function _detect(curMixin, targetMixin, seen) {
 MixinPrototype.detect = function(obj) {
   if (!obj) { return false; }
   if (obj instanceof Mixin) { return _detect(obj, this, {}); }
-  var m = obj.__ember_meta__;
+  var m = readMeta(obj);
   if (!m) { return false; }
   return !!m.peekMixins(guidFor(this));
 };
@@ -645,7 +646,7 @@ MixinPrototype.keys = function() {
 // returns the mixins currently applied to the specified object
 // TODO: Make Ember.mixin
 Mixin.mixins = function(obj) {
-  var m = obj['__ember_meta__'];
+  var m = readMeta(obj);
   var ret = [];
   if (!m) { return ret; }
 

packages/ember-metal/lib/properties.js

@@ -4,7 +4,7 @@
 
 import { assert } from 'ember-metal/debug';
 import isEnabled from 'ember-metal/features';
-import { meta as metaFor } from 'ember-metal/meta';
+import { meta as metaFor, readMeta } from 'ember-metal/meta';
 import { overrideChains } from 'ember-metal/property_events';
 // ..........................................................
 // DESCRIPTOR
@@ -33,7 +33,7 @@ export function MANDATORY_SETTER_FUNCTION(name) {
 
 export function DEFAULT_GETTER_FUNCTION(name) {
   return function GETTER_FUNCTION() {
-    var meta = this['__ember_meta__'];
+    var meta = readMeta(this);
     return meta && meta.peekValues(name);
   };
 }

packages/ember-metal/lib/property_events.js

@@ -7,6 +7,7 @@ import {
 } from 'ember-metal/events';
 import ObserverSet from 'ember-metal/observer_set';
 import { symbol } from 'ember-metal/utils';
+import { readMeta } from 'ember-metal/meta';
 
 export let PROPERTY_DID_CHANGE = symbol('PROPERTY_DID_CHANGE');
 
@@ -35,7 +36,7 @@ var deferred = 0;
   @private
 */
 function propertyWillChange(obj, keyName) {
-  var m = obj['__ember_meta__'];
+  var m = readMeta(obj);
   var watching = (m && m.peekWatching(keyName) > 0) || keyName === 'length';
   var proto = m && m.proto;
   var possibleDesc = obj[keyName];
@@ -75,7 +76,7 @@ function propertyWillChange(obj, keyName) {
   @private
 */
 function propertyDidChange(obj, keyName) {
-  var m = obj['__ember_meta__'];
+  var m = readMeta(obj);
   var watching = (m && m.peekWatching(keyName) > 0) || keyName === 'length';
   var proto = m && m.proto;
   var possibleDesc = obj[keyName];

packages/ember-metal/lib/property_get.js

@@ -11,6 +11,9 @@ import {
   isPath,
   hasThis as pathHasThis
 } from 'ember-metal/path_cache';
+import {
+  readMeta
+} from 'ember-metal/meta';
 
 var FIRST_KEY = /^([^\.]+)/;
 
@@ -57,7 +60,7 @@ export function get(obj, keyName) {
     return obj;
   }
 
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
   var possibleDesc = obj[keyName];
   var desc = (possibleDesc !== null && typeof possibleDesc === 'object' && possibleDesc.isDescriptor) ? possibleDesc : undefined;
   var ret;

packages/ember-metal/lib/property_set.js

@@ -12,6 +12,7 @@ import {
   isPath,
   hasThis as pathHasThis
 } from 'ember-metal/path_cache';
+import { readMeta } from 'ember-metal/meta';
 
 /**
   Sets the value of a property on an object, respecting computed properties
@@ -38,7 +39,7 @@ export function set(obj, keyName, value, tolerant) {
 
   var meta, possibleDesc, desc;
   if (obj) {
-    meta = obj['__ember_meta__'];
+    meta = readMeta(obj);
     possibleDesc = obj[keyName];
     desc = (possibleDesc !== null && typeof possibleDesc === 'object' && possibleDesc.isDescriptor) ? possibleDesc : undefined;
   }

packages/ember-metal/lib/watching.js

@@ -17,6 +17,7 @@ import {
 import {
   isPath
 } from 'ember-metal/path_cache';
+import { readMeta, deleteMeta } from 'ember-metal/meta';
 
 /**
   Starts watching a property on an object. Whenever the property changes,
@@ -45,7 +46,7 @@ function watch(obj, _keyPath, m) {
 export { watch };
 
 export function isWatching(obj, key) {
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
   return (meta && meta.peekWatching(key)) > 0;
 }
 
@@ -75,11 +76,11 @@ var NODE_STACK = [];
   @private
 */
 export function destroy(obj) {
-  var meta = obj['__ember_meta__'];
+  var meta = readMeta(obj);
   var node, nodes, key, nodeObject;
 
   if (meta) {
-    obj['__ember_meta__'] = null;
+    deleteMeta(obj);
     // remove chainWatchers to remove circular references that would prevent GC
     node = meta.readableChains();
     if (node) {

packages/ember-metal/tests/chains_test.js

@@ -4,6 +4,7 @@ import { finishChains } from 'ember-metal/chains';
 import { defineProperty } from 'ember-metal/properties';
 import computed from 'ember-metal/computed';
 import { propertyDidChange } from 'ember-metal/property_events';
+import { readMeta } from 'ember-metal/meta';
 QUnit.module('Chains');
 
 QUnit.test('finishChains should properly copy chains from prototypes to instances', function() {
@@ -14,7 +15,7 @@ QUnit.test('finishChains should properly copy chains from prototypes to instance
 
   var childObj = Object.create(obj);
   finishChains(childObj);
-  ok(obj['__ember_meta__'].readableChains() !== childObj['__ember_meta__'].readableChains(), 'The chains object is copied');
+  ok(readMeta(obj).readableChains() !== readMeta(childObj).readableChains(), 'The chains object is copied');
 });
 
 

packages/ember-runtime/lib/system/each_proxy.js

@@ -22,7 +22,7 @@ import EmptyObject from 'ember-metal/empty_object';
 function EachProxy(content) {
   this._content = content;
   this._keys = undefined;
-  this.__ember_meta__ = undefined;
+  this.__ember_meta__ = null;
 }
 
 EachProxy.prototype = {

packages/ember-runtime/tests/system/object/destroy_test.js

@@ -9,6 +9,7 @@ import {
 } from 'ember-metal/property_events';
 import { testBoth } from 'ember-metal/tests/props_helper';
 import EmberObject from 'ember-runtime/system/object';
+import { readMeta } from 'ember-metal/meta';
 
 QUnit.module('ember-runtime/system/object/destroy_test');
 
@@ -18,13 +19,13 @@ testBoth('should schedule objects to be destroyed at the end of the run loop', f
 
   run(function() {
     obj.destroy();
-    meta = obj['__ember_meta__'];
+    meta = readMeta(obj);
     ok(meta, 'meta is not destroyed immediately');
     ok(get(obj, 'isDestroying'), 'object is marked as destroying immediately');
     ok(!get(obj, 'isDestroyed'), 'object is not destroyed immediately');
   });
 
-  meta = obj['__ember_meta__'];
+  meta = readMeta(obj);
   ok(!meta, 'meta is destroyed after run loop finishes');
   ok(get(obj, 'isDestroyed'), 'object is destroyed after run loop finishes');
 });