Prototype Support for TSServer Request Cancelation (#22437)

extensions/typescript/src/typescriptServiceClient.ts

@@ -112,6 +112,7 @@ export default class TypeScriptServiceClient implements ITypescriptServiceClient
 	private firstStart: number;
 	private lastStart: number;
 	private numberRestarts: number;
+	private cancellationPipeName: string | null = null;
 
 	private requestQueue: RequestItem[];
 	private pendingResponses: number;
@@ -453,6 +454,10 @@ export default class TypeScriptServiceClient implements ITypescriptServiceClient
 					if (this.apiVersion.has208Features()) {
 						args.push('--enableTelemetry');
 					}
+					if (this.apiVersion.has220Features()) {
+						this.cancellationPipeName = electron.getPipeName(`tscancellation-${electron.makeRandomHexString(20)}`);
+						args.push('--cancellationPipeName', this.cancellationPipeName + '*');
+					}
 					electron.fork(modulePath, args, options, (err: any, childProcess: cp.ChildProcess) => {
 						if (err) {
 							this.lastError = err;
@@ -795,6 +800,19 @@ export default class TypeScriptServiceClient implements ITypescriptServiceClient
 				return true;
 			}
 		}
+
+		if (this.apiVersion.has220Features() && this.cancellationPipeName) {
+			if (this.trace !== Trace.Off) {
+				this.logTrace(`TypeScript Service: trying to cancel ongoing request with sequence number ${seq}`);
+			}
+			try {
+				fs.writeFileSync(this.cancellationPipeName + seq, '');
+				return true;
+			} catch (e) {
+				// noop
+			}
+		}
+
 		if (this.trace !== Trace.Off) {
 			this.logTrace(`TypeScript Service: tried to cancel request with sequence number ${seq}. But request got already delivered.`);
 		}

extensions/typescript/src/utils/electron.ts

@@ -17,7 +17,7 @@ export interface IForkOptions {
 	execArgv?: string[];
 }
 
-function makeRandomHexString(length: number): string {
+export function makeRandomHexString(length: number): string {
 	let chars = ['0', '1', '2', '3', '4', '5', '6', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'];
 	let result = '';
 	for (let i = 0; i < length; i++) {
@@ -28,15 +28,20 @@ function makeRandomHexString(length: number): string {
 }
 
 function generatePipeName(): string {
-	var randomName = 'vscode-' + makeRandomHexString(40);
+	return getPipeName(makeRandomHexString(40));
+}
+
+export function getPipeName(name: string): string {
+	const fullName = 'vscode-' + name;
 	if (process.platform === 'win32') {
-		return '\\\\.\\pipe\\' + randomName + '-sock';
+		return '\\\\.\\pipe\\' + fullName + '-sock';
 	}
 
 	// Mac/Unix: use socket file
-	return path.join(os.tmpdir(), randomName + '.sock');
+	return path.join(os.tmpdir(), fullName + '.sock');
 }
 
+
 function generatePatchedEnv(env: any, stdInPipeName: string, stdOutPipeName: string, stdErrPipeName: string): any {
 	// Set the two unique pipe names and the electron flag as process env