101 lines
3.8 KiB
JavaScript
101 lines
3.8 KiB
JavaScript
import { __awaiter, __generator } from "tslib";
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import { E_CANCELED } from './errors';
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var Semaphore = /** @class */ (function () {
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function Semaphore(_maxConcurrency, _cancelError) {
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if (_cancelError === void 0) { _cancelError = E_CANCELED; }
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this._maxConcurrency = _maxConcurrency;
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this._cancelError = _cancelError;
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this._queue = [];
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this._waiters = [];
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if (_maxConcurrency <= 0) {
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throw new Error('semaphore must be initialized to a positive value');
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}
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this._value = _maxConcurrency;
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}
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Semaphore.prototype.acquire = function () {
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var _this = this;
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var locked = this.isLocked();
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var ticketPromise = new Promise(function (resolve, reject) {
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return _this._queue.push({ resolve: resolve, reject: reject });
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});
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if (!locked)
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this._dispatch();
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return ticketPromise;
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};
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Semaphore.prototype.runExclusive = function (callback) {
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return __awaiter(this, void 0, void 0, function () {
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var _a, value, release;
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return __generator(this, function (_b) {
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switch (_b.label) {
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case 0: return [4 /*yield*/, this.acquire()];
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case 1:
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_a = _b.sent(), value = _a[0], release = _a[1];
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_b.label = 2;
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case 2:
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_b.trys.push([2, , 4, 5]);
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return [4 /*yield*/, callback(value)];
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case 3: return [2 /*return*/, _b.sent()];
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case 4:
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release();
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return [7 /*endfinally*/];
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case 5: return [2 /*return*/];
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}
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});
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});
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};
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Semaphore.prototype.waitForUnlock = function () {
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return __awaiter(this, void 0, void 0, function () {
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var waitPromise;
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var _this = this;
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return __generator(this, function (_a) {
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if (!this.isLocked()) {
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return [2 /*return*/, Promise.resolve()];
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}
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waitPromise = new Promise(function (resolve) { return _this._waiters.push({ resolve: resolve }); });
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return [2 /*return*/, waitPromise];
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});
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});
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};
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Semaphore.prototype.isLocked = function () {
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return this._value <= 0;
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};
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/** @deprecated Deprecated in 0.3.0, will be removed in 0.4.0. Use runExclusive instead. */
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Semaphore.prototype.release = function () {
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if (this._maxConcurrency > 1) {
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throw new Error('this method is unavailable on semaphores with concurrency > 1; use the scoped release returned by acquire instead');
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}
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if (this._currentReleaser) {
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var releaser = this._currentReleaser;
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this._currentReleaser = undefined;
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releaser();
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}
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};
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Semaphore.prototype.cancel = function () {
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var _this = this;
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this._queue.forEach(function (ticket) { return ticket.reject(_this._cancelError); });
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this._queue = [];
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};
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Semaphore.prototype._dispatch = function () {
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var _this = this;
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var nextTicket = this._queue.shift();
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if (!nextTicket)
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return;
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var released = false;
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this._currentReleaser = function () {
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if (released)
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return;
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released = true;
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_this._value++;
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_this._resolveWaiters();
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_this._dispatch();
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};
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nextTicket.resolve([this._value--, this._currentReleaser]);
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};
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Semaphore.prototype._resolveWaiters = function () {
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this._waiters.forEach(function (waiter) { return waiter.resolve(); });
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this._waiters = [];
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};
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return Semaphore;
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}());
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export default Semaphore;
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