You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
29 lines
681 B
29 lines
681 B
2 years ago
|
var Class = require('./Class');
|
||
|
|
var Queue = require('./Queue');
|
||
|
|
exports = Class({
|
||
|
|
initialize: function Semaphore() {
|
||
|
|
var counter =
|
||
|
|
arguments.length > 0 && arguments[0] !== undefined
|
||
|
|
? arguments[0]
|
||
|
|
: 1;
|
||
|
|
this._counter = counter;
|
||
|
|
this._tasks = new Queue();
|
||
|
|
},
|
||
|
|
wait: function(fn) {
|
||
|
|
if (this._counter > 0) {
|
||
|
|
this._counter--;
|
||
|
|
return fn();
|
||
|
|
}
|
||
|
|
this._tasks.enqueue(fn);
|
||
|
|
},
|
||
|
|
signal: function() {
|
||
|
|
var task = this._tasks.dequeue();
|
||
|
|
if (task) {
|
||
|
|
return task();
|
||
|
|
}
|
||
|
|
this._counter++;
|
||
|
|
}
|
||
|
|
});
|
||
|
|
|
||
|
|
module.exports = exports;
|