92 lines
2.6 KiB
TypeScript
92 lines
2.6 KiB
TypeScript
import * as plugins from './smartstream.plugins.js';
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export class StreamIntake<T> extends plugins.stream.Readable {
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// STATIC
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public static async fromStream<U>(inputStream: plugins.stream.Readable | ReadableStream, options?: plugins.stream.ReadableOptions): Promise<StreamIntake<U>> {
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const intakeStream = new StreamIntake<U>(options);
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if (inputStream instanceof plugins.stream.Readable) {
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inputStream.on('data', (chunk: U) => {
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intakeStream.pushData(chunk);
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});
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inputStream.on('end', () => {
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intakeStream.signalEnd();
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});
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inputStream.on('error', (err: Error) => {
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intakeStream.destroy(err);
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});
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} else {
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const reader = (inputStream as ReadableStream).getReader();
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const readChunk = () => {
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reader.read().then(({ done, value }) => {
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if (done) {
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intakeStream.signalEnd();
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} else {
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intakeStream.pushData(value);
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readChunk();
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}
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}).catch((err) => {
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intakeStream.destroy(err);
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});
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};
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readChunk();
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}
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return intakeStream;
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}
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// INSTANCE
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private signalEndBoolean = false;
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private chunkStore: T[] = [];
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public pushNextObservable = new plugins.smartrx.ObservableIntake<any>();
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private pushedNextDeferred = plugins.smartpromise.defer();
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constructor(options?: plugins.stream.ReadableOptions) {
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super({ ...options, objectMode: true }); // Ensure that we are in object mode.
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this.pushNextObservable.push('please push next');
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}
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_read(size: number): void {
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// console.log('get next');
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const pushChunk = (): void => {
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while (this.chunkStore.length > 0) {
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// If push returns false, then we should stop reading
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if (!this.push(this.chunkStore.shift())) {
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return;
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}
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}
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if (this.chunkStore.length === 0) {
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if (this.signalEndBoolean) {
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// If we're done, push null to signal the end of the stream
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this.push(null);
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} else {
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// Ask for more data and wait
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this.pushNextObservable.push('please push next');
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this.pushedNextDeferred.promise.then(() => {
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this.pushedNextDeferred = plugins.smartpromise.defer(); // Reset the deferred
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pushChunk(); // Try pushing the next chunk
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});
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}
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}
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};
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pushChunk();
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}
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public pushData(chunkData: T) {
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this.chunkStore.push(chunkData);
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this.pushedNextDeferred.resolve();
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}
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public signalEnd() {
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this.signalEndBoolean = true;
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this.pushedNextDeferred.resolve();
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this.pushNextObservable.signalComplete();
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}
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}
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