Use cursor for counting documents

lib/datastore.js

@@ -353,35 +353,24 @@ Datastore.prototype.insert = function () {
   this.executor.push({ this: this, fn: this._insert, arguments: arguments });
 };
 
+
 /**
  * Count all documents matching the query
  * @param {Object} query MongoDB-style query
- *
- * @api private Use count
  */
-Datastore.prototype._count = function(query, callback) {
-  var res = 0
-    , self = this
-    , candidates = this.getCandidates(query)
-    , i
-    ;
+Datastore.prototype.count = function(query, callback) {
+  var cursor = new Cursor(this, query, function(err, docs, callback) {
+    if (err) { return callback(err); }
+    return callback(null, docs.length);
+  });
 
-  try {
-    for (i = 0; i < candidates.length; i += 1) {
-      if (model.match(candidates[i], query)) {
-        res++;
-      }
-    }
-  } catch (err) {
-    return callback(err);
+  if (typeof callback === 'function') {
+    cursor.exec(callback);
+  } else {
+    return cursor;
   }
-
-  return callback(null, res);
 };
 
-Datastore.prototype.count = function() {
-    this.executor.push({this: this, fn: this._count, arguments: arguments });
-};
 
 /**
  * Find all documents matching the query