GenAIScript

// Import the CancelError class from the error module import { CancelError } from "./error" /** * A cancellation token is passed to an asynchronous or long running * operation to request cancellation, like cancelling a request * for completion items because the user continued to type. * * To get an instance of a `CancellationToken` use a * {@link CancellationTokenSource}. */ export interface CancellationToken { /** * Is `true` when the token has been cancelled, `false` otherwise. * This flag should be checked by operations to decide if they should terminate. */ isCancellationRequested: boolean } /** * Implements the CancellationToken using an AbortSignal * to track the cancellation state. */ export class AbortSignalCancellationToken implements CancellationToken { // Constructor takes an AbortSignal to track cancellation constructor(private readonly signal: AbortSignal) {} // Accessor for checking if the cancellation has been requested get isCancellationRequested() { return this.signal.aborted } } /** * Converts a CancellationToken to an AbortSignal if supported. * If the token lacks a compatible signal property, returns undefined. * * @param token - The CancellationToken to convert. * @returns The associated AbortSignal or undefined if unsupported. */ export function toSignal(token: CancellationToken) { return (token as any)?.signal as AbortSignal } /** * A controller that manages the AbortSignal and its associated CancellationToken. * Useful for creating cancellable operations. */ export class AbortSignalCancellationController { readonly controller: AbortController readonly token: AbortSignalCancellationToken // Initializes the controller and creates a token with the associated signal constructor() { this.controller = new AbortController() this.token = new AbortSignalCancellationToken(this.controller.signal) } /** * Aborts the ongoing operation with an optional reason. * This triggers the cancellation state in the associated token. * * @param reason - Optional reason for aborting the operation. */ abort(reason?: any) { this.controller.abort(reason) } } /** * Checks if the operation has been cancelled and throws an error if so. * Throws a CancelError when the cancellation is requested. * * @param token - The cancellation token to check. * @throws CancelError - If the cancellation has been requested. */ export function checkCancelled(token: CancellationToken) { if (token?.isCancellationRequested) throw new CancelError("user cancelled") } /** * Represents optional cancellation behavior for an operation. * Contains a CancellationToken that can be checked for cancellation requests. */ export interface CancellationOptions { cancellationToken?: CancellationToken }