92 lines
3.1 KiB
TypeScript
92 lines
3.1 KiB
TypeScript
/*
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Copyright 2020 The Matrix.org Foundation C.I.C.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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import {Lock} from "./Lock";
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export class LockMap<T> {
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private readonly _map: Map<T, Lock> = new Map();
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async takeLock(key: T): Promise<Lock> {
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let lock = this._map.get(key);
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if (lock) {
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await lock.take();
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} else {
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lock = new Lock();
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lock.tryTake();
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this._map.set(key, lock);
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}
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// don't leave old locks lying around
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lock.released()!.then(() => {
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// give others a chance to take the lock first
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Promise.resolve().then(() => {
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if (!lock!.isTaken) {
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this._map.delete(key);
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}
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});
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});
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return lock;
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}
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}
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export function tests() {
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return {
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"taking a lock on the same key blocks": async assert => {
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const lockMap = new LockMap();
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const lock = await lockMap.takeLock("foo");
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let second = false;
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const prom = lockMap.takeLock("foo").then(() => {
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second = true;
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});
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assert.equal(second, false);
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// do a delay to make sure prom does not resolve on its own
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await Promise.resolve();
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lock.release();
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await prom;
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assert.equal(second, true);
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},
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"lock is not cleaned up with second request": async assert => {
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const lockMap = new LockMap();
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const lock = await lockMap.takeLock("foo");
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let ranSecond = false;
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const prom = lockMap.takeLock("foo").then(returnedLock => {
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ranSecond = true;
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assert.equal(returnedLock.isTaken, true);
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// peek into internals, naughty
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// @ts-ignore
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assert.equal(lockMap._map.get("foo"), returnedLock);
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});
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lock.release();
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await prom;
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// double delay to make sure cleanup logic ran
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await Promise.resolve();
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await Promise.resolve();
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assert.equal(ranSecond, true);
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},
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"lock is cleaned up without other request": async assert => {
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const lockMap = new LockMap();
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const lock = await lockMap.takeLock("foo");
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await Promise.resolve();
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lock.release();
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// double delay to make sure cleanup logic ran
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await Promise.resolve();
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await Promise.resolve();
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// @ts-ignore
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assert.equal(lockMap._map.has("foo"), false);
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},
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};
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}
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