From 75c4e837350228bceec5407fd12830c480ff8359 Mon Sep 17 00:00:00 2001
From: Rafael Weinstein <rafaelw@chromium.org>
Date: Wed, 3 Jul 2013 14:50:39 -0700
Subject: [PATCH] Observers try to call .unobserved on observed objects when
 they close

---
 change_summary.js       | 21 +++++++++------------
 tests/test.js           | 27 +++++++++++++++++++++++++++
 util/array_reduction.js |  4 ++++
 3 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/change_summary.js b/change_summary.js
index c373733..34ffc36 100644
--- a/change_summary.js
+++ b/change_summary.js
@@ -281,7 +281,8 @@
     return copy;
   }
 
-  function Observer(callback) {
+  function Observer(object, callback) {
+    this.object = object;
     this.callback = callback;
     this.reporting = true;
     if (hasObserve)
@@ -309,7 +310,11 @@
     close: function() {
       if (!this.valid)
         return;
+      if (typeof this.object.unobserved === 'function')
+        this.object.unobserved();
+
       this.disconnect();
+      this.object = undefined;
       this.valid = false;
     },
 
@@ -427,8 +432,7 @@
   }
 
   function ObjectObserver(object, callback) {
-    this.object = object;
-    Observer.call(this, callback);
+    Observer.call(this, object, callback);
   }
 
   ObjectObserver.prototype = createObject({
@@ -476,18 +480,13 @@
         this.oldObject = undefined;
       else if (this.object)
         Object.unobserve(this.object, this.boundInternalCallback);
-
-      this.object = undefined;
     }
   });
 
   function ArrayObserver(array, callback) {
     if (!Array.isArray(array))
       throw Error('Provided object is not an Array');
-
-    this.object = array;
-
-    Observer.call(this, callback);
+    Observer.call(this, array, callback);
   }
 
   ArrayObserver.prototype = createObject({
@@ -605,9 +604,8 @@
     if (!isObject(object))
       return;
 
-    this.object = object;
     this.path = path;
-    Observer.call(this, callback);
+    Observer.call(this, object, callback);
   }
 
   PathObserver.prototype = createObject({
@@ -619,7 +617,6 @@
     },
 
     disconnect: function() {
-      this.object = undefined;
       this.value = undefined;
       if (hasObserve) {
         this.observedSet.reset();
diff --git a/tests/test.js b/tests/test.js
index dbc9b0d..513bbd6 100644
--- a/tests/test.js
+++ b/tests/test.js
@@ -131,6 +131,14 @@ suite('PathObserver Tests', function() {
     callbackInvoked = false;
   }
 
+  test('Close Invokes Unobserved', function() {
+    var called = false;
+    var obj = { foo: 1, unobserved: function() { called = true }};
+    var observer = new PathObserver(obj, 'foo', function() {});
+    observer.close();
+    assert.isTrue(called);
+  });
+
   test('Delivery Until No Changes', function() {
     var obj = { foo: { bar: 5 }};
     var callbackCount = 0;
@@ -729,6 +737,15 @@ suite('ArrayObserver Tests', function() {
     observer.close();
   }
 
+  test('Close Invokes Unobserved', function() {
+    var called = false;
+    var obj = [];
+    obj.unobserved = function() { called = true };
+    var observer = new ArrayObserver(obj, function() {});
+    observer.close();
+    assert.isTrue(called);
+  });
+
   test('Delivery Until No Changes', function() {
     var arr = [0, 1, 2, 3, 4];
     var callbackCount = 0;
@@ -1282,6 +1299,16 @@ suite('ObjectObserver Tests', function() {
     callbackInvoked = false;
   }
 
+  test('Close Invokes Unobserved', function() {
+    var called = false;
+    var obj = {};
+    obj.unobserved = function() { called = true };
+    var observer = new ObjectObserver(obj, function() {});
+    observer.close();
+    assert.isTrue(called);
+  });
+
+
   test('Delivery Until No Changes', function() {
     var obj = { foo: 5 };
     var callbackCount = 0;
diff --git a/util/array_reduction.js b/util/array_reduction.js
index f19c787..709dc83 100644
--- a/util/array_reduction.js
+++ b/util/array_reduction.js
@@ -74,6 +74,10 @@ function ArrayReduction(array, path, reduceFn, initial) {
     arrayObserver.close();
   };
 
+  this.unobserved = function() {
+    self.close();
+  };
+
   this.deliver = function() {
     arrayObserver.deliver();
     observers.forEach(function(observer) {