From ffd2a62c3f7df94365980302fef3bc3376b48182 Mon Sep 17 00:00:00 2001
From: Florian Dold <florian.dold@gmail.com>
Date: Mon, 3 Aug 2020 13:00:48 +0530
Subject: modularize repo, use pnpm, improve typechecking

---
 packages/taler-wallet-core/src/util/asyncMemo.ts | 87 ++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 packages/taler-wallet-core/src/util/asyncMemo.ts

(limited to 'packages/taler-wallet-core/src/util/asyncMemo.ts')

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;
+  }
+}
-- 
cgit v1.2.3