46 lines
1.3 KiB
TypeScript
46 lines
1.3 KiB
TypeScript
/*
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* Copyright (C) 2026 Fluxer Contributors
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*
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* This file is part of Fluxer.
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*
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* Fluxer is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* Fluxer is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
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*/
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import * as metrics from '~/lib/MetricsClient';
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export class InMemoryCoalescer {
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private pending = new Map<string, Promise<unknown>>();
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async coalesce<T>(key: string, fn: () => Promise<T>): Promise<T> {
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const existing = this.pending.get(key) as Promise<T> | undefined;
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if (existing) {
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metrics.counter({name: 'media_proxy.cache.hit'});
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return existing;
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}
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metrics.counter({name: 'media_proxy.cache.miss'});
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const promise = (async () => {
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try {
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return await fn();
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} finally {
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this.pending.delete(key);
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}
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})();
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this.pending.set(key, promise);
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return promise;
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}
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}
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