1 | import { AsyncIterableX } from './asynciterablex';
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2 | const NON_FLOWING = 0;
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3 | const READABLE = 1;
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4 | const ENDED = 2;
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5 | const ERRORED = 3;
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6 | export class ReadableStreamAsyncIterable extends AsyncIterableX {
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7 | constructor(stream, size) {
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8 | super();
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9 | this._stream = stream;
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10 | this._defaultSize = size;
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11 | this._state = NON_FLOWING;
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12 | this._error = null;
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13 | this._rejectFns = new Set();
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14 | const onError = (err) => {
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15 | this._state = ERRORED;
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16 | this._error = err;
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17 | for (const rejectFn of this._rejectFns) {
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18 | rejectFn(err);
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19 | }
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20 | };
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21 | const onEnd = () => {
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22 | this._state = ENDED;
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23 | };
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24 | this._stream['once']('error', onError);
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25 | this._stream['once']('end', onEnd);
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26 | }
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27 | [Symbol.asyncIterator]() {
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28 | return this;
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29 | }
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30 | async next(size = this._defaultSize) {
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31 | if (this._state === NON_FLOWING) {
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32 | await Promise.race([this._waitReadable(), this._waitEnd()]);
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33 | return await this.next(size);
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34 | }
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35 | if (this._state === ENDED) {
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36 | return { done: true, value: undefined };
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37 | }
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38 | if (this._state === ERRORED) {
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39 | throw this._error;
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40 | }
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41 | const value = this._stream['read'](size);
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42 | if (value !== null) {
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43 | return { done: false, value };
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44 | }
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45 | else {
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46 | this._state = NON_FLOWING;
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47 | return await this.next(size);
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48 | }
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49 | }
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50 | _waitReadable() {
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51 | return new Promise((resolve, reject) => {
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52 | const onReadable = () => {
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53 | this._state = READABLE;
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54 | this._rejectFns.delete(reject);
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55 | resolve();
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56 | };
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57 | this._rejectFns.add(reject);
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58 | this._stream['once']('readable', onReadable);
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59 | });
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60 | }
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61 | _waitEnd() {
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62 | if (!this._endPromise) {
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63 | this._endPromise = new Promise((resolve, reject) => {
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64 | const onEnd = () => {
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65 | this._state = ENDED;
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66 | this._rejectFns.delete(reject);
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67 | resolve();
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68 | };
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69 | this._rejectFns.add(reject);
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70 | this._stream['once']('end', onEnd);
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71 | });
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72 | }
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73 | return this._endPromise;
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74 | }
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75 | }
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76 | export function fromNodeStream(stream, size) {
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77 | return new ReadableStreamAsyncIterable(stream, size);
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78 | }
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79 |
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80 |
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