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authorFlorian Dold <florian.dold@gmail.com>2020-08-03 13:00:48 +0530
committerFlorian Dold <florian.dold@gmail.com>2020-08-03 13:01:05 +0530
commitffd2a62c3f7df94365980302fef3bc3376b48182 (patch)
tree270af6f16b4cc7f5da2afdba55c8bc9dbea5eca5 /packages/taler-wallet-core/src/util/asyncMemo.ts
parentaa481e42675fb7c4dcbbeec0ba1c61e1953b9596 (diff)
downloadwallet-core-ffd2a62c3f7df94365980302fef3bc3376b48182.tar.xz
modularize repo, use pnpm, improve typechecking
Diffstat (limited to 'packages/taler-wallet-core/src/util/asyncMemo.ts')
-rw-r--r--packages/taler-wallet-core/src/util/asyncMemo.ts87
1 files changed, 87 insertions, 0 deletions
diff --git a/packages/taler-wallet-core/src/util/asyncMemo.ts b/packages/taler-wallet-core/src/util/asyncMemo.ts
new file mode 100644
index 000000000..6e88081b6
--- /dev/null
+++ b/packages/taler-wallet-core/src/util/asyncMemo.ts
@@ -0,0 +1,87 @@
+/*
+ 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/>
+ */
+
+interface MemoEntry<T> {
+ p: Promise<T>;
+ t: number;
+ n: number;
+}
+
+export class AsyncOpMemoMap<T> {
+ private n = 0;
+ private memoMap: { [k: string]: MemoEntry<T> } = {};
+
+ private cleanUp(key: string, n: number): void {
+ const r = this.memoMap[key];
+ if (r && r.n === n) {
+ delete this.memoMap[key];
+ }
+ }
+
+ memo(key: string, pg: () => Promise<T>): Promise<T> {
+ const res = this.memoMap[key];
+ if (res) {
+ return res.p;
+ }
+ const n = this.n++;
+ // Wrap the operation in case it immediately throws
+ const p = Promise.resolve().then(() => pg());
+ this.memoMap[key] = {
+ p,
+ n,
+ t: new Date().getTime(),
+ };
+ return p.finally(() => {
+ this.cleanUp(key, n);
+ });
+ }
+ clear(): void {
+ this.memoMap = {};
+ }
+}
+
+export class AsyncOpMemoSingle<T> {
+ private n = 0;
+ private memoEntry: MemoEntry<T> | undefined;
+
+ private cleanUp(n: number): void {
+ if (this.memoEntry && this.memoEntry.n === n) {
+ this.memoEntry = undefined;
+ }
+ }
+
+ memo(pg: () => Promise<T>): Promise<T> {
+ const res = this.memoEntry;
+ if (res) {
+ return res.p;
+ }
+ const n = this.n++;
+ // Wrap the operation in case it immediately throws
+ const p = Promise.resolve().then(() => pg());
+ p.finally(() => {
+ this.cleanUp(n);
+ });
+ this.memoEntry = {
+ p,
+ n,
+ t: new Date().getTime(),
+ };
+ return p;
+ }
+ clear(): void {
+ this.memoEntry = undefined;
+ }
+}