/**
 * Exclusive file lock for preventing multiple processes from
 * accessing the same database simultaneously.
 *
 * Uses atomic file creation with O_EXCL flag to ensure only one
 * process can acquire the lock at a time.
 */
export declare class FileLock {
    private locked;
    private readonly filePath;
    private readonly timeoutMs;
    constructor(filePath: string, timeoutMs?: number);
    /**
     * Acquire an exclusive lock on the file.
     * Creates the lock file if it doesn't exist.
     * Retries for up to timeoutMs before throwing DatabaseLockedError.
     */
    acquire(): Promise<void>;
    /**
     * Release the lock by deleting the lock file.
     */
    release(): Promise<void>;
    /**
     * Check if this instance currently holds the lock.
     */
    isLocked(): boolean;
    /**
     * Check if an existing lock file is stale (owning process is dead).
     * Returns true if the lock appears stale and should be recovered.
     */
    private isLockStale;
}
/**
 * Error thrown when attempting to open a database that is
 * already locked by another process.
 */
export declare class DatabaseLockedError extends Error {
    constructor(message: string);
}
/**
 * Error thrown when attempting to write to a database opened in read-only mode.
 */
export declare class ReadOnlyError extends Error {
    constructor(message?: string);
}
/**
 * Error thrown when the lock file cannot be created due to permission issues.
 * This typically happens in read-only filesystems or restricted environments
 * like production containers.
 */
export declare class LockPermissionError extends Error {
    readonly lockPath: string;
    readonly originalError?: Error | undefined;
    constructor(lockPath: string, originalError?: Error | undefined);
}
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