/**
 * Generate a 12-character hex operation identifier.
 *
 * @returns A unique 12-char hex string.
 */
export declare function generateOpId(): string;
/**
 * Compute a SHA-256 hex digest of the provided content.
 *
 * @param content - String content to hash.
 * @returns Lowercase 64-character hex hash.
 */
export declare function computeContentHash(content: string): string;
/**
 * Result of a lockedTransform operation.
 */
export type LockedTransformResult = {
    changed: boolean;
    hash: string;
    opId: string;
    bytesChanged: number;
};
/**
 * Execute a read-lock-transform-write cycle for a single file.
 *
 * 1. Acquires advisory lock via `proper-lockfile`
 * 2. Reads current file content
 * 3. Computes content hash (SHA-256)
 * 4. Optionally checks `expectedHash` for stale-file detection
 * 5. Calls `transform(currentContent, currentHash)` to get new content
 * 6. If unchanged → skips write, returns `{ changed: false, hash }`
 * 7. Writes to temp file → atomic rename to target
 * 8. Releases lock
 * 9. Returns `{ changed: true, hash: newHash, opId, bytesChanged }`
 *
 * @param filePath - Absolute path to the target file.
 * @param transform - Transform function receiving current content + hash.
 * @param options - Optional stale-file detection (`expectedHash`).
 * @returns Write result with change signal and verification data.
 */
export declare function lockedTransform(filePath: string, transform: (content: string, currentHash: string) => string | Promise<string>, options?: {
    expectedHash?: string;
}): Promise<LockedTransformResult>;
/**
 * Sync variant of lockedTransform for hot-path single-section writes.
 *
 * Identical flow but uses sync FS exclusively. No async/await.
 * Note: lockSync does not support retries — fails immediately if lock held.
 *
 * @param filePath - Absolute path to the target file.
 * @param transform - Transform function receiving current content + hash.
 * @param options - Optional stale-file detection (`expectedHash`).
 * @returns Write result with change signal and verification data.
 */
export declare function lockedTransformSync(filePath: string, transform: (content: string, currentHash: string) => string, options?: {
    expectedHash?: string;
}): LockedTransformResult;
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