azurite
Version:
An open source Azure Storage API compatible server
75 lines • 2.12 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
var MutexLockStatus;
(function (MutexLockStatus) {
MutexLockStatus[MutexLockStatus["LOCKED"] = 0] = "LOCKED";
MutexLockStatus[MutexLockStatus["UNLOCKED"] = 1] = "UNLOCKED";
})(MutexLockStatus || (MutexLockStatus = {}));
/**
* An async mutex lock.
*
* @export
* @class Mutex
*/
class Mutex {
/**
* Lock for a specific key. If the lock has been acquired by another customer, then
* will wait until getting the lock.
*
* @static
* @param {string} key lock key
* @returns {Promise<void>}
* @memberof Mutex
*/
static async lock(key) {
return new Promise((resolve) => {
if (this.keys[key] === undefined || this.keys[key] === MutexLockStatus.UNLOCKED) {
this.keys[key] = MutexLockStatus.LOCKED;
resolve();
}
else {
this.onUnlockEvent(key, () => {
this.keys[key] = MutexLockStatus.LOCKED;
resolve();
});
}
});
}
/**
* Unlock a key.
*
* @static
* @param {string} key
* @returns {Promise<void>}
* @memberof Mutex
*/
static async unlock(key) {
return new Promise((resolve) => {
if (this.keys[key] === MutexLockStatus.LOCKED) {
this.emitUnlockEvent(key);
}
delete this.keys[key];
resolve();
});
}
static onUnlockEvent(key, handler) {
if (this.listeners[key] === undefined) {
this.listeners[key] = [handler];
}
else {
this.listeners[key].push(handler);
}
}
static emitUnlockEvent(key) {
if (this.listeners[key] !== undefined && this.listeners[key].length > 0) {
const handler = this.listeners[key].shift();
setImmediate(() => {
handler.call(this);
});
}
}
}
Mutex.keys = {};
Mutex.listeners = {};
exports.default = Mutex;
//# sourceMappingURL=Mutex.js.map