[BUGFIX release] [PERF] Cleanup Proxy

* remove `on(‘init`, just use the existing `init`
* remove redundant meta lookups
* remove observer (notify proxy change from a unified place, within markObjectAsDirty)
* remove double `tag` lookups
* remove redundant meta guards
* misc cleanup

packages/ember-metal/lib/meta.js

@@ -131,6 +131,14 @@ export class Meta {
     return this.proto !== obj;
   }
 
+  setTag(tag) {
+    this._tag = tag;
+  }
+
+  getTag(tag) {
+    return this._tag;
+  }
+
   destroy() {
     if (this.isMetaDestroyed()) { return; }
 

packages/ember-metal/lib/property_events.js

@@ -83,12 +83,12 @@ function propertyWillChange(obj, keyName, _meta) {
 */
 function propertyDidChange(obj, keyName, _meta) {
   let meta = _meta || peekMeta(obj);
+  let hasMeta = !!meta;
 
-  if (meta && !meta.isInitialized(obj)) {
+  if (hasMeta && !meta.isInitialized(obj)) {
     return;
   }
 
-  let watching = meta && meta.peekWatching(keyName) > 0;
   let possibleDesc = obj[keyName];
   let desc = (possibleDesc !== null && typeof possibleDesc === 'object' && possibleDesc.isDescriptor) ? possibleDesc : undefined;
 
@@ -97,23 +97,23 @@ function propertyDidChange(obj, keyName, _meta) {
     desc.didChange(obj, keyName);
   }
 
-  if (watching) {
-    if (meta.hasDeps(keyName)) {
+  if (hasMeta && meta.peekWatching(keyName) > 0) {
+    if (meta.hasDeps(keyName) && !meta.isSourceDestroying()) {
       dependentKeysDidChange(obj, keyName, meta);
     }
 
     chainsDidChange(obj, keyName, meta, false);
     notifyObservers(obj, keyName, meta);
   }
 
-
   if (obj[PROPERTY_DID_CHANGE]) {
     obj[PROPERTY_DID_CHANGE](keyName);
   }
 
-  if (meta && meta.isSourceDestroying()) { return; }
-
-  markObjectAsDirty(meta, keyName);
+  if (hasMeta) {
+    if (meta.isSourceDestroying()) { return; }
+    markObjectAsDirty(meta, keyName);
+  }
 
   if (EMBER_GLIMMER_DETECT_BACKTRACKING_RERENDER || EMBER_GLIMMER_ALLOW_BACKTRACKING_RERENDER) {
     assertNotRendered(obj, keyName, meta);
@@ -123,9 +123,8 @@ function propertyDidChange(obj, keyName, _meta) {
 let WILL_SEEN, DID_SEEN;
 // called whenever a property is about to change to clear the cache of any dependent keys (and notify those properties of changes, etc...)
 function dependentKeysWillChange(obj, depKey, meta) {
-  if (meta && meta.isSourceDestroying()) { return; }
-
-  if (meta && meta.hasDeps(depKey)) {
+  if (meta.isSourceDestroying()) { return; }
+  if (meta.hasDeps(depKey)) {
     let seen = WILL_SEEN;
     let top = !seen;
 
@@ -143,21 +142,17 @@ function dependentKeysWillChange(obj, depKey, meta) {
 
 // called whenever a property has just changed to update dependent keys
 function dependentKeysDidChange(obj, depKey, meta) {
-  if (meta && meta.isSourceDestroying()) { return; }
+  let seen = DID_SEEN;
+  let top = !seen;
 
-  if (meta && meta.hasDeps(depKey)) {
-    let seen = DID_SEEN;
-    let top = !seen;
-
-    if (top) {
-      seen = DID_SEEN = {};
-    }
+  if (top) {
+    seen = DID_SEEN = {};
+  }
 
-    iterDeps(propertyDidChange, obj, depKey, seen, meta);
+  iterDeps(propertyDidChange, obj, depKey, seen, meta);
 
-    if (top) {
-      DID_SEEN = null;
-    }
+  if (top) {
+    DID_SEEN = null;
   }
 }
 
@@ -258,7 +253,7 @@ function changeProperties(callback, binding) {
 }
 
 function notifyBeforeObservers(obj, keyName, meta) {
-  if (meta && meta.isSourceDestroying()) { return; }
+  if (meta.isSourceDestroying()) { return; }
 
   let eventName = `${keyName}:before`;
   let listeners, added;
@@ -272,7 +267,7 @@ function notifyBeforeObservers(obj, keyName, meta) {
 }
 
 function notifyObservers(obj, keyName, meta) {
-  if (meta && meta.isSourceDestroying()) { return; }
+  if (meta.isSourceDestroying()) { return; }
 
   let eventName = `${keyName}:change`;
   let listeners;

packages/ember-metal/lib/tags.js

@@ -40,19 +40,23 @@ export function tagFor(object, _meta) {
 }
 
 export function markObjectAsDirty(meta, propertyKey) {
-  let objectTag = meta && meta.readableTag();
+  let objectTag = meta.readableTag();
 
   if (objectTag) {
     objectTag.dirty();
   }
 
-  let tags = meta && meta.readableTags();
+  let tags = meta.readableTags();
   let propertyTag = tags && tags[propertyKey];
 
   if (propertyTag) {
     propertyTag.dirty();
   }
 
+  if (propertyKey === 'content' && meta.isProxy()) {
+    meta.getTag().contentDidChange();
+  }
+
   if (objectTag || propertyTag) {
     ensureRunloop();
   }

packages/ember-runtime/lib/mixins/-proxy.js

@@ -84,22 +84,13 @@ export default Mixin.create({
 
   init() {
     this._super(...arguments);
-    meta(this).setProxy();
+    let m = meta(this);
+    m.setProxy();
+    m.setTag(new ProxyTag(this));
   },
 
-  _initializeTag: on('init', function() {
-    meta(this)._tag = new ProxyTag(this);
-  }),
-
-  _contentDidChange: observer('content', function() {
-    assert('Can\'t set Proxy\'s content to itself', get(this, 'content') !== this);
-    tagFor(this).contentDidChange();
-  }),
-
   isTruthy: bool('content'),
 
-  _debugContainerKey: null,
-
   willWatchProperty(key) {
     let contentKey = `content.${key}`;
     _addBeforeObserver(this, contentKey, null, contentPropertyWillChange);
@@ -126,6 +117,9 @@ export default Mixin.create({
 
   setUnknownProperty(key, value) {
     let m = meta(this);
+
+    assert('Can\'t set Proxy\'s content to itself', value !== this);
+
     if (m.proto === this) {
       // if marked as prototype then just defineProperty
       // rather than delegate
@@ -141,6 +135,7 @@ export default Mixin.create({
       !this.isController,
       { id: 'ember-runtime.controller-proxy', until: '3.0.0' }
     );
+
     return set(content, key, value);
   }
 });