@azure/storage-file-datalake
Version:
Microsoft Azure Storage SDK for JavaScript - DataLake
91 lines • 3.45 kB
JavaScript
;
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
Object.defineProperty(exports, "__esModule", { value: true });
exports.fsCreateReadStream = exports.fsStat = void 0;
exports.streamToBuffer = streamToBuffer;
exports.streamToBuffer2 = streamToBuffer2;
const tslib_1 = require("tslib");
const node_fs_1 = tslib_1.__importDefault(require("node:fs"));
const node_util_1 = tslib_1.__importDefault(require("node:util"));
/**
* Reads a readable stream into buffer. Fill the buffer from offset to end.
*
* @param stream - A Node.js Readable stream
* @param buffer - Buffer to be filled, length must greater than or equal to offset
* @param offset - From which position in the buffer to be filled, inclusive
* @param end - To which position in the buffer to be filled, exclusive
* @param encoding - Encoding of the Readable stream
*/
async function streamToBuffer(stream, buffer, offset, end, encoding) {
let pos = 0; // Position in stream
const count = end - offset; // Total amount of data needed in stream
return new Promise((resolve, reject) => {
stream.on("readable", () => {
if (pos >= count) {
resolve();
return;
}
let chunk = stream.read();
if (!chunk) {
return;
}
if (typeof chunk === "string") {
chunk = Buffer.from(chunk, encoding);
}
// How much data needed in this chunk
const chunkLength = pos + chunk.length > count ? count - pos : chunk.length;
buffer.fill(chunk.slice(0, chunkLength), offset + pos, offset + pos + chunkLength);
pos += chunkLength;
});
stream.on("end", () => {
if (pos < count) {
reject(new Error(`Stream drains before getting enough data needed. Data read: ${pos}, data need: ${count}`));
}
resolve();
});
stream.on("error", reject);
});
}
/**
* Reads a readable stream into buffer entirely.
*
* @param stream - A Node.js Readable stream
* @param buffer - Buffer to be filled, length must greater than or equal to offset
* @param encoding - Encoding of the Readable stream
* @returns with the count of bytes read.
* @throws `RangeError` If buffer size is not big enough.
*/
async function streamToBuffer2(stream, buffer, encoding) {
let pos = 0; // Position in stream
const bufferSize = buffer.length;
return new Promise((resolve, reject) => {
stream.on("readable", () => {
let chunk = stream.read();
if (!chunk) {
return;
}
if (typeof chunk === "string") {
chunk = Buffer.from(chunk, encoding);
}
if (pos + chunk.length > bufferSize) {
reject(new Error(`Stream exceeds buffer size. Buffer size: ${bufferSize}`));
return;
}
buffer.fill(chunk, pos, pos + chunk.length);
pos += chunk.length;
});
stream.on("end", () => {
resolve(pos);
});
stream.on("error", reject);
});
}
/**
* ONLY AVAILABLE IN NODE.JS RUNTIME.
*
* Promisified version of fs.stat().
*/
exports.fsStat = node_util_1.default.promisify(node_fs_1.default.stat);
exports.fsCreateReadStream = node_fs_1.default.createReadStream;
//# sourceMappingURL=utils.js.map