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https://github.com/ckaczor/azuredatastudio.git
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Merge from vscode a5cf1da01d5db3d2557132be8d30f89c38019f6c (#8525)
* Merge from vscode a5cf1da01d5db3d2557132be8d30f89c38019f6c * remove files we don't want * fix hygiene * update distro * update distro * fix hygiene * fix strict nulls * distro * distro * fix tests * fix tests * add another edit * fix viewlet icon * fix azure dialog * fix some padding * fix more padding issues
This commit is contained in:
Anthony Dresser
487
src/vs/base/common/stream.ts
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487
src/vs/base/common/stream.ts
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/*---------------------------------------------------------------------------------------------
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* Copyright (c) Microsoft Corporation. All rights reserved.
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* Licensed under the Source EULA. See License.txt in the project root for license information.
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*--------------------------------------------------------------------------------------------*/
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/**
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* The payload that flows in readable stream events.
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*/
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export type ReadableStreamEventPayload<T> = T | Error | 'end';
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export interface ReadableStreamEvents<T> {
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/**
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* The 'data' event is emitted whenever the stream is
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* relinquishing ownership of a chunk of data to a consumer.
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*/
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on(event: 'data', callback: (data: T) => void): void;
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/**
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* Emitted when any error occurs.
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*/
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on(event: 'error', callback: (err: Error) => void): void;
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/**
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* The 'end' event is emitted when there is no more data
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* to be consumed from the stream. The 'end' event will
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* not be emitted unless the data is completely consumed.
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*/
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on(event: 'end', callback: () => void): void;
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}
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/**
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* A interface that emulates the API shape of a node.js readable
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* stream for use in desktop and web environments.
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*/
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export interface ReadableStream<T> extends ReadableStreamEvents<T> {
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/**
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* Stops emitting any events until resume() is called.
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*/
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pause(): void;
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/**
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* Starts emitting events again after pause() was called.
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*/
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resume(): void;
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/**
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* Destroys the stream and stops emitting any event.
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*/
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destroy(): void;
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}
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/**
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* A interface that emulates the API shape of a node.js readable
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* for use in desktop and web environments.
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*/
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export interface Readable<T> {
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/**
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* Read data from the underlying source. Will return
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* null to indicate that no more data can be read.
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*/
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read(): T | null;
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}
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/**
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* A interface that emulates the API shape of a node.js writeable
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* stream for use in desktop and web environments.
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*/
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export interface WriteableStream<T> extends ReadableStream<T> {
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/**
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* Writing data to the stream will trigger the on('data')
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* event listener if the stream is flowing and buffer the
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* data otherwise until the stream is flowing.
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*/
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write(data: T): void;
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/**
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* Signals an error to the consumer of the stream via the
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* on('error') handler if the stream is flowing.
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*/
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error(error: Error): void;
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/**
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* Signals the end of the stream to the consumer. If the
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* result is not an error, will trigger the on('data') event
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* listener if the stream is flowing and buffer the data
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* otherwise until the stream is flowing.
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*
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* In case of an error, the on('error') event will be used
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* if the stream is flowing.
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*/
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end(result?: T | Error): void;
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}
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export function isReadableStream<T>(obj: any): obj is ReadableStream<T> {
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const candidate: ReadableStream<T> = obj;
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return candidate && [candidate.on, candidate.pause, candidate.resume, candidate.destroy].every(fn => typeof fn === 'function');
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}
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export interface IReducer<T> {
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(data: T[]): T;
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}
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export interface IDataTransformer<Original, Transformed> {
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(data: Original): Transformed;
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}
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export interface IErrorTransformer {
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(error: Error): Error;
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}
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export interface ITransformer<Original, Transformed> {
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data: IDataTransformer<Original, Transformed>;
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error?: IErrorTransformer;
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}
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export function newWriteableStream<T>(reducer: IReducer<T>): WriteableStream<T> {
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return new WriteableStreamImpl<T>(reducer);
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}
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class WriteableStreamImpl<T> implements WriteableStream<T> {
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private readonly state = {
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flowing: false,
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ended: false,
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destroyed: false
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};
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private readonly buffer = {
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data: [] as T[],
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error: [] as Error[]
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};
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private readonly listeners = {
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data: [] as { (data: T): void }[],
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error: [] as { (error: Error): void }[],
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end: [] as { (): void }[]
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};
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constructor(private reducer: IReducer<T>) { }
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pause(): void {
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if (this.state.destroyed) {
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return;
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}
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this.state.flowing = false;
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}
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resume(): void {
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if (this.state.destroyed) {
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return;
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}
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if (!this.state.flowing) {
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this.state.flowing = true;
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// emit buffered events
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this.flowData();
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this.flowErrors();
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this.flowEnd();
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}
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}
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write(data: T): void {
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if (this.state.destroyed) {
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return;
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}
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// flowing: directly send the data to listeners
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if (this.state.flowing) {
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this.listeners.data.forEach(listener => listener(data));
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}
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// not yet flowing: buffer data until flowing
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else {
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this.buffer.data.push(data);
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}
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}
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error(error: Error): void {
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if (this.state.destroyed) {
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return;
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}
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// flowing: directly send the error to listeners
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if (this.state.flowing) {
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this.listeners.error.forEach(listener => listener(error));
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}
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// not yet flowing: buffer errors until flowing
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else {
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this.buffer.error.push(error);
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}
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}
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end(result?: T | Error): void {
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if (this.state.destroyed) {
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return;
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}
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// end with data or error if provided
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if (result instanceof Error) {
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this.error(result);
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} else if (result) {
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this.write(result);
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}
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// flowing: send end event to listeners
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if (this.state.flowing) {
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this.listeners.end.forEach(listener => listener());
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this.destroy();
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}
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// not yet flowing: remember state
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else {
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this.state.ended = true;
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}
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}
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on(event: 'data', callback: (data: T) => void): void;
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on(event: 'error', callback: (err: Error) => void): void;
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on(event: 'end', callback: () => void): void;
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on(event: 'data' | 'error' | 'end', callback: (arg0?: any) => void): void {
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if (this.state.destroyed) {
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return;
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}
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switch (event) {
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case 'data':
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this.listeners.data.push(callback);
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// switch into flowing mode as soon as the first 'data'
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// listener is added and we are not yet in flowing mode
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this.resume();
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break;
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case 'end':
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this.listeners.end.push(callback);
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// emit 'end' event directly if we are flowing
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// and the end has already been reached
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//
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// finish() when it went through
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if (this.state.flowing && this.flowEnd()) {
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this.destroy();
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}
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break;
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case 'error':
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this.listeners.error.push(callback);
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// emit buffered 'error' events unless done already
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// now that we know that we have at least one listener
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if (this.state.flowing) {
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this.flowErrors();
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}
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break;
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}
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}
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private flowData(): void {
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if (this.buffer.data.length > 0) {
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const fullDataBuffer = this.reducer(this.buffer.data);
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this.listeners.data.forEach(listener => listener(fullDataBuffer));
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this.buffer.data.length = 0;
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}
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}
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private flowErrors(): void {
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if (this.listeners.error.length > 0) {
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for (const error of this.buffer.error) {
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this.listeners.error.forEach(listener => listener(error));
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}
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this.buffer.error.length = 0;
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}
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}
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private flowEnd(): boolean {
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if (this.state.ended) {
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this.listeners.end.forEach(listener => listener());
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return this.listeners.end.length > 0;
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}
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return false;
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}
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destroy(): void {
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if (!this.state.destroyed) {
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this.state.destroyed = true;
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this.state.ended = true;
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this.buffer.data.length = 0;
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this.buffer.error.length = 0;
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this.listeners.data.length = 0;
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this.listeners.error.length = 0;
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this.listeners.end.length = 0;
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}
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}
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}
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/**
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* Helper to fully read a T readable into a T.
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*/
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export function consumeReadable<T>(readable: Readable<T>, reducer: IReducer<T>): T {
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const chunks: T[] = [];
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let chunk: T | null;
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while ((chunk = readable.read()) !== null) {
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chunks.push(chunk);
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}
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return reducer(chunks);
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}
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/**
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* Helper to read a T readable up to a maximum of chunks. If the limit is
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* reached, will return a readable instead to ensure all data can still
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* be read.
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*/
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export function consumeReadableWithLimit<T>(readable: Readable<T>, reducer: IReducer<T>, maxChunks: number): T | Readable<T> {
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const chunks: T[] = [];
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let chunk: T | null | undefined = undefined;
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while ((chunk = readable.read()) !== null && chunks.length < maxChunks) {
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chunks.push(chunk);
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}
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// If the last chunk is null, it means we reached the end of
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// the readable and return all the data at once
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if (chunk === null && chunks.length > 0) {
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return reducer(chunks);
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}
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// Otherwise, we still have a chunk, it means we reached the maxChunks
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// value and as such we return a new Readable that first returns
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// the existing read chunks and then continues with reading from
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// the underlying readable.
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return {
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read: () => {
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// First consume chunks from our array
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if (chunks.length > 0) {
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return chunks.shift()!;
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}
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// Then ensure to return our last read chunk
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if (typeof chunk !== 'undefined') {
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const lastReadChunk = chunk;
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// explicitly use undefined here to indicate that we consumed
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// the chunk, which could have either been null or valued.
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chunk = undefined;
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return lastReadChunk;
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}
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// Finally delegate back to the Readable
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return readable.read();
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}
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};
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}
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/**
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* Helper to fully read a T stream into a T.
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*/
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export function consumeStream<T>(stream: ReadableStream<T>, reducer: IReducer<T>): Promise<T> {
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return new Promise((resolve, reject) => {
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const chunks: T[] = [];
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stream.on('data', data => chunks.push(data));
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stream.on('error', error => reject(error));
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stream.on('end', () => resolve(reducer(chunks)));
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});
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}
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/**
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* Helper to read a T stream up to a maximum of chunks. If the limit is
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* reached, will return a stream instead to ensure all data can still
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* be read.
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*/
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export function consumeStreamWithLimit<T>(stream: ReadableStream<T>, reducer: IReducer<T>, maxChunks: number): Promise<T | ReadableStream<T>> {
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return new Promise((resolve, reject) => {
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const chunks: T[] = [];
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let wrapperStream: WriteableStream<T> | undefined = undefined;
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stream.on('data', data => {
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// If we reach maxChunks, we start to return a stream
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// and make sure that any data we have already read
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// is in it as well
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if (!wrapperStream && chunks.length === maxChunks) {
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wrapperStream = newWriteableStream(reducer);
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while (chunks.length) {
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wrapperStream.write(chunks.shift()!);
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}
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wrapperStream.write(data);
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return resolve(wrapperStream);
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}
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if (wrapperStream) {
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wrapperStream.write(data);
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} else {
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chunks.push(data);
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}
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});
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stream.on('error', error => {
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if (wrapperStream) {
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wrapperStream.error(error);
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} else {
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return reject(error);
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}
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});
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stream.on('end', () => {
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if (wrapperStream) {
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while (chunks.length) {
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wrapperStream.write(chunks.shift()!);
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}
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wrapperStream.end();
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} else {
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return resolve(reducer(chunks));
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}
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});
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});
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}
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/**
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* Helper to create a readable stream from an existing T.
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*/
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export function toStream<T>(t: T, reducer: IReducer<T>): ReadableStream<T> {
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const stream = newWriteableStream<T>(reducer);
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stream.end(t);
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return stream;
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}
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/**
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* Helper to convert a T into a Readable<T>.
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*/
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export function toReadable<T>(t: T): Readable<T> {
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let consumed = false;
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return {
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read: () => {
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if (consumed) {
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return null;
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}
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consumed = true;
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return t;
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}
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};
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}
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/**
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* Helper to transform a readable stream into another stream.
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*/
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export function transform<Original, Transformed>(stream: ReadableStreamEvents<Original>, transformer: ITransformer<Original, Transformed>, reducer: IReducer<Transformed>): ReadableStream<Transformed> {
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const target = newWriteableStream<Transformed>(reducer);
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stream.on('data', data => target.write(transformer.data(data)));
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stream.on('end', () => target.end());
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stream.on('error', error => target.error(transformer.error ? transformer.error(error) : error));
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return target;
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}
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Reference in New Issue
Block a user