/* Ensure a Collection is fetched and has entries before running a block of code. */

_.extend(Backbone.Collection.prototype, {
  ensureFetched: function(callback) {
    if (this.length == 0 || this._alreadyEnsureFetched) {
      var _this = this;
      var _refresher = function() {
        _this.unbind('refresh', _refresher);
        callback.apply(_this);
        _this._alreadyEnsureFetched = true;
      };
      this.bind('refresh', _refresher);
      this.fetch();
    } else {
      callback.apply(this);
    }
  }
});