import type { AdapterLaunchBarrier, ILogger } from '@debugmcp/shared';
import type { DebugProtocol } from '@vscode/debugprotocol';
const DEFAULT_TIMEOUT_MS = 5000;
const ADAPTER_CONNECTED_DELAY_MS = 500;
/**
* Coordinates js-debug launch readiness by waiting for either a 'stopped' DAP
* event or the adapter transport connection, mirroring the legacy behavior that
* lived inside ProxyManager.
*/
export class JsDebugLaunchBarrier implements AdapterLaunchBarrier {
readonly awaitResponse = false;
private readonly logger?: ILogger;
private readonly timeoutMs: number;
private resolve!: () => void;
private reject!: (error: Error) => void;
private readonly promise: Promise<void>;
private timeoutHandle: NodeJS.Timeout | null = null;
private adapterConnectedHandle: NodeJS.Timeout | null = null;
private settled = false;
constructor(logger?: ILogger, timeoutMs: number = DEFAULT_TIMEOUT_MS) {
this.logger = logger;
this.timeoutMs = timeoutMs;
this.promise = new Promise<void>((resolve, reject) => {
this.resolve = resolve;
this.reject = reject;
});
this.timeoutHandle = setTimeout(() => {
if (this.settled) {
return;
}
this.logger?.warn?.(
`[JavascriptAdapter] js-debug launch timeout after ${this.timeoutMs}ms, proceeding anyway`
);
this.resolveBarrier();
}, this.timeoutMs);
}
onRequestSent(requestId: string): void {
this.logger?.info?.(
`[JavascriptAdapter] js-debug launch request dispatched (requestId=${requestId})`
);
}
onProxyStatus(status: string): void {
if (this.settled || status !== 'adapter_connected') {
return;
}
if (this.adapterConnectedHandle) {
clearTimeout(this.adapterConnectedHandle);
}
this.adapterConnectedHandle = setTimeout(() => {
if (this.settled) {
return;
}
this.logger?.info?.(
'[JavascriptAdapter] js-debug adapter connected; treating launch as ready'
);
this.resolveBarrier();
}, ADAPTER_CONNECTED_DELAY_MS);
}
onDapEvent(event: string, body: DebugProtocol.Event['body'] | undefined): void {
void body;
if (this.settled || event !== 'stopped') {
return;
}
this.logger?.info?.('[JavascriptAdapter] js-debug launch confirmed by stopped event');
this.resolveBarrier();
}
onProxyExit(code: number | null, signal: string | null): void {
if (this.settled) {
return;
}
const error = new Error(
`Proxy exited before js-debug launch completed (code=${code}, signal=${signal ?? 'null'})`
);
this.rejectBarrier(error);
}
waitUntilReady(): Promise<void> {
return this.promise;
}
dispose(): void {
if (this.timeoutHandle) {
clearTimeout(this.timeoutHandle);
this.timeoutHandle = null;
}
if (this.adapterConnectedHandle) {
clearTimeout(this.adapterConnectedHandle);
this.adapterConnectedHandle = null;
}
}
private resolveBarrier(): void {
if (this.settled) {
return;
}
this.settled = true;
this.dispose();
this.resolve();
}
private rejectBarrier(error: Error): void {
if (this.settled) {
return;
}
this.settled = true;
this.dispose();
this.reject(error);
}
}
