81 lines
3.0 KiB
JavaScript
81 lines
3.0 KiB
JavaScript
import mergeStreams from '@sindresorhus/merge-streams';
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import {isStandardStream} from '../utils/standard-stream.js';
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import {incrementMaxListeners} from '../utils/max-listeners.js';
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import {TRANSFORM_TYPES} from '../stdio/type.js';
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import {pipeStreams} from './pipeline.js';
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// Handle `input`, `inputFile`, `stdin`, `stdout` and `stderr` options, after spawning, in async mode
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// When multiple input streams are used, we merge them to ensure the output stream ends only once each input stream has ended
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export const pipeOutputAsync = (subprocess, fileDescriptors, controller) => {
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const pipeGroups = new Map();
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for (const [fdNumber, {stdioItems, direction}] of Object.entries(fileDescriptors)) {
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for (const {stream} of stdioItems.filter(({type}) => TRANSFORM_TYPES.has(type))) {
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pipeTransform(subprocess, stream, direction, fdNumber);
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}
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for (const {stream} of stdioItems.filter(({type}) => !TRANSFORM_TYPES.has(type))) {
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pipeStdioItem({
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subprocess,
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stream,
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direction,
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fdNumber,
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pipeGroups,
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controller,
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});
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}
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}
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for (const [outputStream, inputStreams] of pipeGroups.entries()) {
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const inputStream = inputStreams.length === 1 ? inputStreams[0] : mergeStreams(inputStreams);
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pipeStreams(inputStream, outputStream);
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}
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};
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// When using transforms, `subprocess.stdin|stdout|stderr|stdio` is directly mutated
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const pipeTransform = (subprocess, stream, direction, fdNumber) => {
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if (direction === 'output') {
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pipeStreams(subprocess.stdio[fdNumber], stream);
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} else {
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pipeStreams(stream, subprocess.stdio[fdNumber]);
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}
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const streamProperty = SUBPROCESS_STREAM_PROPERTIES[fdNumber];
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if (streamProperty !== undefined) {
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subprocess[streamProperty] = stream;
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}
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subprocess.stdio[fdNumber] = stream;
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};
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const SUBPROCESS_STREAM_PROPERTIES = ['stdin', 'stdout', 'stderr'];
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// Most `std*` option values involve piping `subprocess.std*` to a stream.
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// The stream is either passed by the user or created internally.
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const pipeStdioItem = ({subprocess, stream, direction, fdNumber, pipeGroups, controller}) => {
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if (stream === undefined) {
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return;
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}
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setStandardStreamMaxListeners(stream, controller);
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const [inputStream, outputStream] = direction === 'output'
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? [stream, subprocess.stdio[fdNumber]]
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: [subprocess.stdio[fdNumber], stream];
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const outputStreams = pipeGroups.get(inputStream) ?? [];
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pipeGroups.set(inputStream, [...outputStreams, outputStream]);
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};
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// Multiple subprocesses might be piping from/to `process.std*` at the same time.
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// This is not necessarily an error and should not print a `maxListeners` warning.
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const setStandardStreamMaxListeners = (stream, {signal}) => {
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if (isStandardStream(stream)) {
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incrementMaxListeners(stream, MAX_LISTENERS_INCREMENT, signal);
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}
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};
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// `source.pipe(destination)` adds at most 1 listener for each event.
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// If `stdin` option is an array, the values might be combined with `merge-streams`.
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// That library also listens for `source` end, which adds 1 more listener.
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const MAX_LISTENERS_INCREMENT = 2;
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