69 lines
2.4 KiB
JavaScript
69 lines
2.4 KiB
JavaScript
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"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.ReadableWebToNodeStream = void 0;
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const readable_stream_1 = require("readable-stream");
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/**
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* Converts a Web-API stream into Node stream.Readable class
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* Node stream readable: https://nodejs.org/api/stream.html#stream_readable_streams
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* Web API readable-stream: https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream
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* Node readable stream: https://nodejs.org/api/stream.html#stream_readable_streams
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*/
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class ReadableWebToNodeStream extends readable_stream_1.Readable {
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/**
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*
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* @param stream ReadableStream: https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream
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*/
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constructor(stream) {
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super();
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this.bytesRead = 0;
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this.released = false;
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this.reader = stream.getReader();
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}
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/**
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* Implementation of readable._read(size).
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* When readable._read() is called, if data is available from the resource,
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* the implementation should begin pushing that data into the read queue
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* https://nodejs.org/api/stream.html#stream_readable_read_size_1
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*/
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async _read() {
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// Should start pushing data into the queue
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// Read data from the underlying Web-API-readable-stream
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if (this.released) {
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this.push(null); // Signal EOF
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return;
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}
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this.pendingRead = this.reader.read();
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const data = await this.pendingRead;
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// clear the promise before pushing pushing new data to the queue and allow sequential calls to _read()
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delete this.pendingRead;
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if (data.done || this.released) {
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this.push(null); // Signal EOF
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}
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else {
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this.bytesRead += data.value.length;
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this.push(data.value); // Push new data to the queue
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}
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}
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/**
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* If there is no unresolved read call to Web-API ReadableStream immediately returns;
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* otherwise will wait until the read is resolved.
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*/
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async waitForReadToComplete() {
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if (this.pendingRead) {
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await this.pendingRead;
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}
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}
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/**
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* Close wrapper
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*/
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async close() {
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await this.syncAndRelease();
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}
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async syncAndRelease() {
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this.released = true;
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await this.waitForReadToComplete();
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await this.reader.releaseLock();
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}
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}
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exports.ReadableWebToNodeStream = ReadableWebToNodeStream;
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//# sourceMappingURL=index.js.map
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