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73 lines
2 KiB
TypeScript
73 lines
2 KiB
TypeScript
// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
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import { MuxAsyncIterator } from "../async/mux_async_iterator.ts";
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export type Disposable = { dispose: () => void };
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/**
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* Generates an AsyncIterable which can be awaited on for one or more signals.
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* `dispose()` can be called when you are finished waiting on the events.
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*
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* Example:
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*
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* const sig = signal(Deno.Signal.SIGUSR1, Deno.Signal.SIGINT);
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* setTimeout(() => {}, 5000); // Prevents exiting immediately
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*
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* for await (const _ of sig) {
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* console.log("interrupt or usr1 signal received");
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* }
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*
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* // At some other point in your code when finished listening:
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* sig.dispose();
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*
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* @param signos - one or more `Deno.Signal`s to await on
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*/
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export function signal(
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...signos: [number, ...number[]]
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): AsyncIterable<void> & Disposable {
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const mux = new MuxAsyncIterator<void>();
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if (signos.length < 1) {
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throw new Error(
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"No signals are given. You need to specify at least one signal to create a signal stream.",
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);
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}
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const streams = signos.map(Deno.signal);
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streams.forEach((stream) => {
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mux.add(stream);
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});
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// Create dispose method for the muxer of signal streams.
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const dispose = (): void => {
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streams.forEach((stream) => {
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stream.dispose();
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});
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};
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return Object.assign(mux, { dispose });
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}
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/**
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* Registers a callback function to be called on triggering of a signal event.
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*
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* const handle = onSignal(Deno.Signal.SIGINT, () => {
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* console.log('Received SIGINT');
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* handle.dispose(); // de-register from receiving further events
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* });
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*
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* @param signo One of Deno.Signal (e.g. Deno.Signal.SIGINT)
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* @param callback Callback function triggered upon signal event
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*/
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export function onSignal(signo: number, callback: () => void): Disposable {
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const sig = signal(signo);
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// allows `sig` to be returned before blocking on the await
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(async (): Promise<void> => {
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for await (const _ of sig) {
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callback();
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}
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})();
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return sig;
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}
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