2021-10-11 16:52:17 +02:00

105 lines
2.9 KiB
TypeScript

/**
* Copyright (c) Microsoft Corporation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import { makeWaitForNextTask } from '../utils/utils';
export interface WritableStream {
write(data: Buffer): void;
}
export interface ReadableStream {
on(event: 'data', callback: (b: Buffer) => void): void;
on(event: 'close', callback: () => void): void;
}
export interface ClosableStream {
close(): void;
}
export class Transport {
private _pipeWrite: WritableStream;
private _data = Buffer.from([]);
private _waitForNextTask = makeWaitForNextTask();
private _closed = false;
private _bytesLeft = 0;
onmessage?: (message: string) => void;
onclose?: () => void;
private _endian: 'be' | 'le';
private _closeableStream: ClosableStream | undefined;
constructor(pipeWrite: WritableStream, pipeRead: ReadableStream, closeable?: ClosableStream, endian: 'be' | 'le' = 'le') {
this._pipeWrite = pipeWrite;
this._endian = endian;
this._closeableStream = closeable;
pipeRead.on('data', buffer => this._dispatch(buffer));
pipeRead.on('close', () => {
this._closed = true;
if (this.onclose)
this.onclose();
});
this.onmessage = undefined;
this.onclose = undefined;
}
send(message: string) {
if (this._closed)
throw new Error('Pipe has been closed');
const data = Buffer.from(message, 'utf-8');
const dataLength = Buffer.alloc(4);
if (this._endian === 'be')
dataLength.writeUInt32BE(data.length, 0);
else
dataLength.writeUInt32LE(data.length, 0);
this._pipeWrite.write(dataLength);
this._pipeWrite.write(data);
}
close() {
// Let it throw.
this._closeableStream!.close();
}
_dispatch(buffer: Buffer) {
this._data = Buffer.concat([this._data, buffer]);
while (true) {
if (!this._bytesLeft && this._data.length < 4) {
// Need more data.
break;
}
if (!this._bytesLeft) {
this._bytesLeft = this._endian === 'be' ? this._data.readUInt32BE(0) : this._data.readUInt32LE(0);
this._data = this._data.slice(4);
}
if (!this._bytesLeft || this._data.length < this._bytesLeft) {
// Need more data.
break;
}
const message = this._data.slice(0, this._bytesLeft);
this._data = this._data.slice(this._bytesLeft);
this._bytesLeft = 0;
this._waitForNextTask(() => {
if (this.onmessage)
this.onmessage(message.toString('utf-8'));
});
}
}
}