Network Topology graph "twitches"

the graph is redrawn which causes visual glitching.
Depending on the graph complexity.

my patch resolved this issue so I compare between previous
data and received data, if that changed it will redrawn,
otherwise it keeps running.

Change-Id: I813dfb329f46cda9afacce89c9a8b84eb2827115
Closes-Bug: #1716834

openstack_dashboard/static/js/horizon.networktopologycommon.js

@@ -20,6 +20,59 @@ horizon.networktopologycommon = {
   }
 };
 
+function isEqual(data1, data2) {
+  var list1=[],list2=[];
+  function compare2Objects (data1, data2) {
+    var item;
+
+    if (isNaN(data1) && isNaN(data2) && typeof data1 === 'number' && typeof data2 === 'number') {
+    return true;
+    }
+
+    // Compare primitives and functions.
+    // Check if both arguments link to the same object.
+    // Especially useful on the step where we compare prototypes
+    if (data1 === data2) {
+    return true;
+    }
+    for (item in data1) {
+        if (data2.hasOwnProperty(item) !== data1.hasOwnProperty(item)) {
+            return false;
+        }
+        else if (typeof data2[item] !== typeof data1[item]) {
+            return false;
+        }
+
+        switch (typeof (data1[item])) {
+            case 'object':
+            if (!compare2Objects (data1[item], data2[item])) {
+                    return false;
+                }
+                break;
+
+            default:
+                if (data1[item] !== data2[item]) {
+                    list1.push(data1[item]);
+                    list2.push(data2[item]);
+                }
+                break;
+        }
+    }
+    return true;
+  }
+  if(!compare2Objects(data1, data2)){
+      return false;
+  }else{
+      list1 = list1.sort();
+      list2 = list2.sort();
+      for(var i in list1){
+          if(list2[i]!=list1[i])
+              return false;
+      }
+  }
+  return true;
+}
+
 /**
  * Common data loader for network topology views
  */
@@ -30,7 +83,7 @@ horizon.networktopologyloader = {
   reload_duration: 10000,
   // timer controlling update intervals
   update_timer: null,
-
+  previous_data : {},
   init:function() {
     var self = this;
     if($('#networktopology').length === 0) {
@@ -48,9 +101,12 @@ horizon.networktopologyloader = {
       angular.element('#networktopology').data('networktopology') + '?' + angular.element.now(),
       function(data) {
         self.model = data;
-        $('#networktopology').trigger('change');
+        if(!isEqual(data,self.previous_data)) {
+            angular.copy(data, self.previous_data);
+            $('#networktopology').trigger('change');
+        }
         self.update_timer = setTimeout(function(){
-          self.update();
+        self.update();
         }, self.reload_duration);
       }
     );