1 files changed, 213 insertions, 0 deletions
diff --git a/packages/taler-util/src/timer.ts b/packages/taler-util/src/timer.ts
new file mode 100644
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+++ b/packages/taler-util/src/timer.ts
@@ -0,0 +1,213 @@
+/*
+ This file is part of GNU Taler
+ (C) 2017-2019 Taler Systems S.A.
+
+ 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/>
+ */
+
+/**
+ * Cross-platform timers.
+ *
+ * NodeJS and the browser use slightly different timer API,
+ * this abstracts over these differences.
+ */
+
+/**
+ * Imports.
+ */
+import { Logger, Duration } from "@gnu-taler/taler-util";
+
+const logger = new Logger("timer.ts");
+
+/**
+ * Cancelable timer.
+ */
+export interface TimerHandle {
+  clear(): void;
+
+  /**
+   * Make sure the event loop exits when the timer is the
+   * only event left.  Has no effect in the browser.
+   */
+  unref(): void;
+}
+
+class IntervalHandle {
+  constructor(public h: any) {}
+
+  clear(): void {
+    clearInterval(this.h);
+  }
+
+  /**
+   * Make sure the event loop exits when the timer is the
+   * only event left.  Has no effect in the browser.
+   */
+  unref(): void {
+    if (typeof this.h === "object" && "unref" in this.h) {
+      this.h.unref();
+    }
+  }
+}
+
+class TimeoutHandle {
+  constructor(public h: any) {}
+
+  clear(): void {
+    clearTimeout(this.h);
+  }
+
+  /**
+   * Make sure the event loop exits when the timer is the
+   * only event left.  Has no effect in the browser.
+   */
+  unref(): void {
+    if (typeof this.h === "object" && "unref" in this.h) {
+      this.h.unref();
+    }
+  }
+}
+
+/**
+ * Get a performance counter in nanoseconds.
+ */
+export const performanceNow: () => bigint = (() => {
+  // @ts-ignore
+  if (typeof process !== "undefined" && process.hrtime) {
+    return () => {
+      return process.hrtime.bigint();
+    };
+  }
+
+  // @ts-ignore
+  if (typeof performance !== "undefined") {
+    // @ts-ignore
+    return () => BigInt(Math.floor(performance.now() * 1000)) * BigInt(1000);
+  }
+
+  return () => BigInt(new Date().getTime()) * BigInt(1000) * BigInt(1000);
+})();
+
+const nullTimerHandle = {
+  clear() {
+    // do nothing
+    return;
+  },
+  unref() {
+    // do nothing
+    return;
+  },
+};
+
+/**
+ * Group of timers that can be destroyed at once.
+ */
+export interface TimerAPI {
+  after(delayMs: number, callback: () => void): TimerHandle;
+  every(delayMs: number, callback: () => void): TimerHandle;
+}
+
+export class SetTimeoutTimerAPI implements TimerAPI {
+  /**
+   * Call a function every time the delay given in milliseconds passes.
+   */
+  every(delayMs: number, callback: () => void): TimerHandle {
+    return new IntervalHandle(setInterval(callback, delayMs));
+  }
+
+  /**
+   * Call a function after the delay given in milliseconds passes.
+   */
+  after(delayMs: number, callback: () => void): TimerHandle {
+    return new TimeoutHandle(setTimeout(callback, delayMs));
+  }
+}
+
+export const timer = new SetTimeoutTimerAPI();
+
+/**
+ * Implementation of [[TimerGroup]] using setTimeout
+ */
+export class TimerGroup {
+  private stopped = false;
+
+  private readonly timerMap: { [index: number]: TimerHandle } = {};
+
+  private idGen = 1;
+
+  constructor(public readonly timerApi: TimerAPI) {}
+
+  stopCurrentAndFutureTimers(): void {
+    this.stopped = true;
+    for (const x in this.timerMap) {
+      if (!this.timerMap.hasOwnProperty(x)) {
+        continue;
+      }
+      this.timerMap[x].clear();
+      delete this.timerMap[x];
+    }
+  }
+
+  resolveAfter(delayMs: Duration): Promise<void> {
+    return new Promise<void>((resolve, reject) => {
+      if (delayMs.d_ms !== "forever") {
+        this.after(delayMs.d_ms, () => {
+          resolve();
+        });
+      }
+    });
+  }
+
+  after(delayMs: number, callback: () => void): TimerHandle {
+    if (this.stopped) {
+      logger.warn("dropping timer since timer group is stopped");
+      return nullTimerHandle;
+    }
+    const h = this.timerApi.after(delayMs, callback);
+    const myId = this.idGen++;
+    this.timerMap[myId] = h;
+
+    const tm = this.timerMap;
+
+    return {
+      clear() {
+        h.clear();
+        delete tm[myId];
+      },
+      unref() {
+        h.unref();
+      },
+    };
+  }
+
+  every(delayMs: number, callback: () => void): TimerHandle {
+    if (this.stopped) {
+      logger.warn("dropping timer since timer group is stopped");
+      return nullTimerHandle;
+    }
+    const h = this.timerApi.every(delayMs, callback);
+    const myId = this.idGen++;
+    this.timerMap[myId] = h;
+
+    const tm = this.timerMap;
+
+    return {
+      clear() {
+        h.clear();
+        delete tm[myId];
+      },
+      unref() {
+        h.unref();
+      },
+    };
+  }
+}