/**
 * Update Lock
 * Issue #1198: guard `POST /api/app/update` against concurrent self-updates.
 *
 * Design constraints:
 * - Acquisition is a single O_EXCL create (mirrors PidManager.writePid), so two
 *   concurrent requests cannot both win.
 * - A successful update restarts the server, so nothing survives to release the
 *   lock. Timeout expiry is therefore the primary release path, and
 *   releaseUpdateLock() exists only for the spawn-failed case.
 *
 * @module lib/app-update/update-lock
 */
/** Lock file name inside the config directory */
export declare const UPDATE_LOCK_FILENAME = "update.lock";
/**
 * Age after which a lock is considered abandoned.
 * `commandmate update` takes tens of seconds (npm install dominates); 10 minutes
 * is well clear of that while still recovering from a killed update process.
 */
export declare const UPDATE_LOCK_TIMEOUT_MS: number;
/**
 * Absolute path of the update lock file.
 */
export declare function getUpdateLockPath(): string;
/**
 * Take the update lock.
 *
 * @param now - Current epoch ms (injectable for tests)
 * @returns true when the caller now holds the lock, false when an update is in progress
 */
export declare function acquireUpdateLock(now?: number): boolean;
/**
 * Drop the update lock.
 * Only meaningful when the update never started (spawn failure): a started
 * update replaces this process, so the lock outlives it until it expires.
 */
export declare function releaseUpdateLock(): void;
//# sourceMappingURL=update-lock.d.ts.map