Function downloadRemoteFileToPath

packages/core/src/sync/sync-files.ts:113–149

(
  backend: ISyncBackend,
  remotePath: string,
  localPath: string,
  onProgress?: (loaded: number, total: number) => void,
)

}

async function downloadRemoteFileToPath(
  backend: ISyncBackend,
  remotePath: string,
  localPath: string,
  onProgress?: (loaded: number, total: number) => void,
): Promise<number | null> {
  const adapter = getSyncAdapter();

  if (backend.getFileToPath) {
    const tempPath = await makeTempTransferPath(localPath);
    try {
      await backend.getFileToPath(remotePath, tempPath, onProgress);
      const dir = getDirName(localPath);
      if (dir) await adapter.ensureDir(dir);
      await adapter.copyFile(tempPath, localPath);
      return null;
    } catch (e) {
      if (!isDirectFileTransferUnsupported(e)) throw e;
      console.warn(
        `[Sync] Direct download unsupported for ${remotePath}; falling back to buffered download`,
      );
    } finally {
      try {
        await adapter.deleteFile(tempPath);
      } catch {}
    }
  }

  const data = backend.getWithProgress
    ? await backend.getWithProgress(remotePath, onProgress)
    : await backend.get(remotePath);
  const dir = getDirName(localPath);
  if (dir) await adapter.ensureDir(dir);
  await adapter.writeFileBytes(localPath, data);
  onProgress?.(data.length, data.length);
  return data.length;
}

type BookRow = {
  id: string;