76 lines
2.5 KiB
JavaScript
76 lines
2.5 KiB
JavaScript
import { Transform } from 'node:stream';
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import { PonyfillReadableStream } from './ReadableStream.js';
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import { endStream } from './utils.js';
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import { PonyfillWritableStream } from './WritableStream.js';
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export class PonyfillTransformStream {
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transform;
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writable;
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readable;
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constructor(transformer) {
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if (transformer instanceof Transform) {
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this.transform = transformer;
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}
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else if (transformer) {
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const controller = {
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enqueue(chunk) {
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transform.push(chunk);
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},
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error(reason) {
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transform.destroy(reason);
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},
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terminate() {
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endStream(transform);
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},
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get desiredSize() {
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return transform.writableLength;
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},
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};
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const transform = new Transform({
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read() { },
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write(chunk, _encoding, callback) {
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try {
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const result = transformer.transform?.(chunk, controller);
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if (result instanceof Promise) {
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result.then(() => {
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callback();
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}, err => {
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callback(err);
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});
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}
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else {
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callback();
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}
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}
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catch (err) {
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callback(err);
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}
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},
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final(callback) {
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try {
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const result = transformer.flush?.(controller);
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if (result instanceof Promise) {
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result.then(() => {
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callback();
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}, err => {
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callback(err);
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});
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}
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else {
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callback();
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}
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}
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catch (err) {
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callback(err);
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}
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},
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});
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this.transform = transform;
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}
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else {
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this.transform = new Transform();
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}
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this.writable = new PonyfillWritableStream(this.transform);
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this.readable = new PonyfillReadableStream(this.transform);
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}
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}
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