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Diffstat (limited to 'src/util/asyncMemo.ts')
-rw-r--r-- | src/util/asyncMemo.ts | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/util/asyncMemo.ts b/src/util/asyncMemo.ts new file mode 100644 index 000000000..8b7b1c9bb --- /dev/null +++ b/src/util/asyncMemo.ts @@ -0,0 +1,52 @@ +/* + This file is part of GNU Taler + (C) 2019 GNUnet e.V. + + GNU Taler is free software; you can redistribute it and/or modify it under the + terms of the GNU General Public License as published by the Free Software + Foundation; either version 3, or (at your option) any later version. + + GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + A PARTICULAR PURPOSE. See the GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along with + GNU Taler; see the file COPYING. If not, see <http://www.gnu.org/licenses/> + */ + +export interface MemoEntry<T> { + p: Promise<T>; + t: number; + n: number; +} + +export class AsyncOpMemo<T> { + n = 0; + memo: { [k: string]: MemoEntry<T> } = {}; + put(key: string, p: Promise<T>): Promise<T> { + const n = this.n++; + this.memo[key] = { + p, + n, + t: new Date().getTime(), + }; + p.finally(() => { + const r = this.memo[key]; + if (r && r.n === n) { + delete this.memo[key]; + } + }); + return p; + } + find(key: string): Promise<T> | undefined { + const res = this.memo[key]; + const tNow = new Date().getTime(); + if (res && res.t < tNow - 10 * 1000) { + delete this.memo[key]; + return; + } else if (res) { + return res.p; + } + return; + } +}
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