Function n

guard.js:48–69

* Creates a condition that allows only n simultaneous executions * of a guarded function * @param {number} allowed number of allowed simultaneous executions * @returns {function} condition function which returns a promise that * fulfills when the critical section may be entered. The fulfil

(allowed)

	 *  section has been exited.
	 */
	function n(allowed) {
		var count = 0;
		var waiting = [];

		return function enter() {
			return when.promise(function(resolve) {
				if(count < allowed) {
					resolve(exit);
				} else {
					waiting.push(resolve);
				}
				count += 1;
			});
		};

		function exit() {
			count = Math.max(count - 1, 0);
			if(waiting.length > 0) {
				waiting.shift()(exit);
			}
		}
	}

});
}(typeof define === 'function' && define.amd ? define : function(factory) { module.exports = factory(require); }));