Changing the caching mechanism to allow it to store at particular level.

Some data will be applicable to parent level, even though - it has
been fetched it from a particular node.

i.e.
roles will be applicable to server level (not particular role level).

web/pgadmin/browser/static/js/node.ui.js

@@ -40,17 +40,19 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
       // That means - we needs to fetch the options from that node.
       if (url) {
         var node = this.field.get('schema_node'),
+            node_info = this.field.get('node_info'),
             full_url = node.generate_url.apply(
               node, [
                 null, url, this.field.get('node_data'),
-                this.field.get('url_with_id') || false, this.field.get('node_info')
+                this.field.get('url_with_id') || false, node_info
               ]),
+            cache_level = this.field.get('cache_level'),
             /*
              * We needs to check, if we have already cached data for this url.
              * If yes - use that, and do not bother about fetching it again,
              * and use it.
              */
-            data = node.cache(full_url);
+            data = node.cache(url, node_info, cache_level);
         if (_.isUndefined(data) || _.isNull(data)) {
           m.trigger('pgadmin-view:fetching', m, self.field);
           $.ajax({
@@ -61,17 +63,17 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
                * We will cache this data for short period of time for avoiding
                * same calls.
                */
-              data = node.cache(full_url, res.data);
+              data = node.cache(url, node_info, cache_level, res.data);
             },
             error: function() {
               m.trigger('pgadmin-view:fetch:error', m, self.field);
             }
           });
           m.trigger('pgadmin-view:fetched', m, self.field);
-        } else {
-          // To fetch only options from cache, we do not need time from 'at' attribute but only options
-          data = data.data;
         }
+        // To fetch only options from cache, we do not need time from 'at'
+        // attribute but only options.
+        data = data.data;
 
         /*
          * Transform the data

web/pgadmin/browser/templates/browser/js/node.js

@@ -1459,16 +1459,36 @@ function($, _, S, pgAdmin, Menu, Backbone, Alertify, Backform) {
 
       return res;
     },
-    cache: function(url, data) {
-      var cached = this.cached = this.cached || {};
+    cache: function(url, node_info, level, data) {
+      var cached = this.cached = this.cached || {},
+          hash = url,
+          min_priority = (
+              node_info && node_info[level] && node_info[level].priority
+              ) || 0;
 
-      if (_.isUndefined(data)) {
-        return cached[url];
+      if (node_info) {
+        _.each(
+            _.sortBy(
+              _.values(
+                _.pick(
+                  node_info,
+                  function(v, k, o) {
+                    console.log(arguments);
+                    return (v.priority <= min_priority);
+                  })),
+              function(o) { return o.priority; }),
+            function(o) {
+              hash = S('%s/%s').sprintf(hash, encodeURI(o._id)).value();
+            });
       }
 
-      cached[url] = {data: data, at: Date()};
+      if (_.isUndefined(data)) {
+        return cached[hash];
+      }
 
-      return data;
+      var res = cached[hash] = {data: data, at: Date(), level: level};
+
+      return res;
     }
   });