https://github.com/Microsoft/TypeScript
Tip revision: b7d31bcd69d88ffab78b82757d05b81451b44986 authored by Daniel Rosenwasser on 09 November 2021, 02:23:49 UTC
Switch to sparse array for deferred nodes.
Switch to sparse array for deferred nodes.
Tip revision: b7d31bc
cancellationToken.ts
/// <reference types="node"/>
import fs = require("fs");
interface ServerCancellationToken {
isCancellationRequested(): boolean;
setRequest(requestId: number): void;
resetRequest(requestId: number): void;
}
function pipeExists(name: string): boolean {
// Unlike statSync, existsSync doesn't throw an exception if the target doesn't exist.
// A comment in the node code suggests they're stuck with that decision for back compat
// (https://github.com/nodejs/node/blob/9da241b600182a9ff400f6efc24f11a6303c27f7/lib/fs.js#L222).
// Caveat: If a named pipe does exist, the first call to existsSync will return true, as for
// statSync. Subsequent calls will return false, whereas statSync would throw an exception
// indicating that the pipe was busy. The difference is immaterial, since our statSync
// implementation returned false from its catch block.
return fs.existsSync(name);
}
function createCancellationToken(args: string[]): ServerCancellationToken {
let cancellationPipeName: string | undefined;
for (let i = 0; i < args.length - 1; i++) {
if (args[i] === "--cancellationPipeName") {
cancellationPipeName = args[i + 1];
break;
}
}
if (!cancellationPipeName) {
return {
isCancellationRequested: () => false,
setRequest: (_requestId: number): void => void 0,
resetRequest: (_requestId: number): void => void 0
};
}
// cancellationPipeName is a string without '*' inside that can optionally end with '*'
// when client wants to signal cancellation it should create a named pipe with name=<cancellationPipeName>
// server will synchronously check the presence of the pipe and treat its existence as indicator that current request should be canceled.
// in case if client prefers to use more fine-grained schema than one name for all request it can add '*' to the end of cancellationPipeName.
// in this case pipe name will be build dynamically as <cancellationPipeName><request_seq>.
if (cancellationPipeName.charAt(cancellationPipeName.length - 1) === "*") {
const namePrefix = cancellationPipeName.slice(0, -1);
if (namePrefix.length === 0 || namePrefix.indexOf("*") >= 0) {
throw new Error("Invalid name for template cancellation pipe: it should have length greater than 2 characters and contain only one '*'.");
}
let perRequestPipeName: string | undefined;
let currentRequestId: number;
return {
isCancellationRequested: () => perRequestPipeName !== undefined && pipeExists(perRequestPipeName),
setRequest(requestId: number) {
currentRequestId = requestId;
perRequestPipeName = namePrefix + requestId;
},
resetRequest(requestId: number) {
if (currentRequestId !== requestId) {
throw new Error(`Mismatched request id, expected ${currentRequestId}, actual ${requestId}`);
}
perRequestPipeName = undefined;
}
};
}
else {
return {
isCancellationRequested: () => pipeExists(cancellationPipeName!), // TODO: GH#18217
setRequest: (_requestId: number): void => void 0,
resetRequest: (_requestId: number): void => void 0
};
}
}
export = createCancellationToken;