WebStreamDefaultReader.jsā¢2.09 kB
import { EndOfStreamError } from './Errors.js';
import { AbstractStreamReader } from "./AbstractStreamReader.js";
export class WebStreamDefaultReader extends AbstractStreamReader {
constructor(reader) {
super();
this.reader = reader;
this.buffer = null; // Internal buffer to store excess data
}
/**
* Copy chunk to target, and store the remainder in this.buffer
*/
writeChunk(target, chunk) {
const written = Math.min(chunk.length, target.length);
target.set(chunk.subarray(0, written));
// Adjust the remainder of the buffer
if (written < chunk.length) {
this.buffer = chunk.subarray(written);
}
else {
this.buffer = null;
}
return written;
}
/**
* Read from stream
* @param buffer - Target Uint8Array (or Buffer) to store data read from stream in
* @param mayBeLess - If true, may fill the buffer partially
* @protected Bytes read
*/
async readFromStream(buffer, mayBeLess) {
if (buffer.length === 0)
return 0;
let totalBytesRead = 0;
// Serve from the internal buffer first
if (this.buffer) {
totalBytesRead += this.writeChunk(buffer, this.buffer);
}
// Continue reading from the stream if more data is needed
while (totalBytesRead < buffer.length && !this.endOfStream) {
const result = await this.reader.read();
if (result.done) {
this.endOfStream = true;
break;
}
if (result.value) {
totalBytesRead += this.writeChunk(buffer.subarray(totalBytesRead), result.value);
}
}
if (!mayBeLess && totalBytesRead === 0 && this.endOfStream) {
throw new EndOfStreamError();
}
return totalBytesRead;
}
abort() {
this.interrupted = true;
return this.reader.cancel();
}
async close() {
await this.abort();
this.reader.releaseLock();
}
}