Function acquireFileLock

src/core/file-state.ts:119–162

(
  options: FileLockOptions
)

}

export async function acquireFileLock(
  options: FileLockOptions
): Promise<nodeFs.promises.FileHandle> {
  const { lockPath, errorFor } = options;
  const lockDir = path.dirname(lockPath);
  await FileSystemUtils.createDirectory(lockDir);
  if (!(await FileSystemUtils.canWriteFile(lockDir))) {
    throw errorFor('create-failed', { lockPath, cause: 'EACCES' });
  }
  const deadline = Date.now() + LOCK_DEADLINE_MS;

  while (true) {
    try {
      return await fs.open(lockPath, 'wx');
    } catch (error) {
      if (!isNodeErrorCode(error, 'EEXIST')) {
        // A permission or filesystem problem, not contention - say so.
        throw errorFor('create-failed', { lockPath, cause: error });
      }

      // A crashed process leaves the lock behind forever; state-file
      // writes are sub-second, so an old lock is an orphan - steal it.
      let staleStolen = false;
      try {
        const lockStat = await fs.stat(lockPath);
        if (Date.now() - lockStat.mtimeMs > STALE_LOCK_THRESHOLD_MS) {
          await fs.rm(lockPath, { force: true });
          staleStolen = true;
        }
      } catch {
        // The holder released between open and stat - retry, but stay
        // bounded: a persistently failing stat (EPERM, delete-pending)
        // must hit the deadline instead of spinning forever.
      }

      if (!staleStolen) {
        if (Date.now() >= deadline) {
          throw errorFor('timeout', { lockPath });
        }
        await sleep(LOCK_POLL_MS);
      }
    }
  }
}

export async function releaseFileLock(
  lock: nodeFs.promises.FileHandle,