const DEFAULT_MAX_HOLD_MS = 5 * 60 * 1000;

const DEFAULT_WATCHDOG_INTERVAL_MS = 60_000;

const DEFAULT_TIMEOUT_GRACE_MS = 2 * 60 * 1000;

// A payload-less lock can be left behind if shutdown lands between open("wx")

// and the owner metadata write. Keep the grace short so 10s callers recover.

const ORPHAN_LOCK_PAYLOAD_GRACE_MS = 5_000;

const MAX_LOCK_HOLD_MS = 2_147_000_000;

type CleanupState = {

try {

const stat = await fs.stat(lockPath);

const ageMs = Math.max(0, nowMs - stat.mtimeMs);

return ageMs > staleMs;

return ageMs > Math.min(staleMs, ORPHAN_LOCK_PAYLOAD_GRACE_MS);

} catch (error) {

const code = (error as { code?: string } | null)?.code;

return code !== "ENOENT";

let handle: fs.FileHandle | null = null;

try {

handle = await fs.open(lockPath, "wx");

const createdAt = new Date().toISOString();

const starttime = getProcessStartTime(process.pid);

const lockPayload: LockFilePayload = { pid: process.pid, createdAt };

if (starttime !== null) {

lockPayload.starttime = starttime;

}

await handle.writeFile(JSON.stringify(lockPayload, null, 2), "utf8");

const createdHeld: HeldLock = {

count: 1,

handle,

maxHoldMs,

};

HELD_LOCKS.set(normalizedSessionFile, createdHeld);

const createdAt = new Date().toISOString();

const starttime = getProcessStartTime(process.pid);

const lockPayload: LockFilePayload = { pid: process.pid, createdAt };

if (starttime !== null) {

lockPayload.starttime = starttime;

}

await handle.writeFile(JSON.stringify(lockPayload, null, 2), "utf8");

return {

release: async () => {

await releaseHeldLock(normalizedSessionFile, createdHeld);

},

};

} catch (err) {

if (handle) {

const currentHeld = HELD_LOCKS.get(normalizedSessionFile);

if (currentHeld?.handle === handle) {

HELD_LOCKS.delete(normalizedSessionFile);

if (HELD_LOCKS.size === 0) {

stopWatchdogTimer();

}

}

try {

await handle.close();

} catch {