code: function ( uri, property, value ) {
  		uri = utility.parse( uri ).href;
  
  		if ( cache.items[uri] === undefined ) {
  			cache.items[uri] = {};
  			cache.items[uri].permission = 0;
  		}
  
  		if ( property === "permission" ) {
  			cache.items[uri].permission |= value;
  		}
  		else if ( property === "!permission" ) {
  			cache.items[uri].permission &= ~value;
  		}
  		else {
  			cache.items[uri][property] = value;
  		}
  
  		return cache.items[uri];
  	}
docs: Sets, or updates an item in cache.items
  
  @method set
  @private
  @param  {String} uri      URI to set or update
  @param  {String} property Property of the cached URI to set
  @param  {Mixed} value     Value to set
  @return {Mixed}           URI Object {headers, response} or undefined