@azure/storage-blob
Version:
Microsoft Azure Storage SDK for JavaScript - Blob
86 lines • 3.41 kB
JavaScript
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
import { AvroReadable } from "./AvroReadable.js";
import { AbortError } from "@azure/abort-controller";
import { Buffer } from "buffer";
const ABORT_ERROR = new AbortError("Reading from the avro stream was aborted.");
export class AvroReadableFromStream extends AvroReadable {
_position;
_readable;
toUint8Array(data) {
if (typeof data === "string") {
return Buffer.from(data);
}
return data;
}
constructor(readable) {
super();
this._readable = readable;
this._position = 0;
}
get position() {
return this._position;
}
async read(size, options = {}) {
if (options.abortSignal?.aborted) {
throw ABORT_ERROR;
}
if (size < 0) {
throw new Error(`size parameter should be positive: ${size}`);
}
if (size === 0) {
return new Uint8Array();
}
if (!this._readable.readable) {
throw new Error("Stream no longer readable.");
}
// See if there is already enough data.
const chunk = this._readable.read(size);
if (chunk) {
this._position += chunk.length;
// chunk.length maybe less than desired size if the stream ends.
return this.toUint8Array(chunk);
}
else {
// register callback to wait for enough data to read
return new Promise((resolve, reject) => {
/* eslint-disable @typescript-eslint/no-use-before-define */
const cleanUp = () => {
this._readable.removeListener("readable", readableCallback);
this._readable.removeListener("error", rejectCallback);
this._readable.removeListener("end", rejectCallback);
this._readable.removeListener("close", rejectCallback);
if (options.abortSignal) {
options.abortSignal.removeEventListener("abort", abortHandler);
}
};
const readableCallback = () => {
const callbackChunk = this._readable.read(size);
if (callbackChunk) {
this._position += callbackChunk.length;
cleanUp();
// callbackChunk.length maybe less than desired size if the stream ends.
resolve(this.toUint8Array(callbackChunk));
}
};
const rejectCallback = () => {
cleanUp();
reject();
};
const abortHandler = () => {
cleanUp();
reject(ABORT_ERROR);
};
this._readable.on("readable", readableCallback);
this._readable.once("error", rejectCallback);
this._readable.once("end", rejectCallback);
this._readable.once("close", rejectCallback);
if (options.abortSignal) {
options.abortSignal.addEventListener("abort", abortHandler);
}
/* eslint-enable @typescript-eslint/no-use-before-define */
});
}
}
}
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