Function readBack

packages/dofs/src/fs/writeFile.test.ts:13–39

(db: Database, path: string)

// A deliberately minimal helper so writeFile tests can stand alone
// without depending on readFile.
function readBack(db: Database, path: string): Uint8Array {
  const node = resolveInode(db, path);
  if (node === null) throw new Error(`no such path: ${path}`);
  if (node.type !== "file") throw new Error(`not a file: ${path}`);
  const chunks = db.all<{ hash: Uint8Array; size: number }>(
    "SELECT hash, size FROM vfs_chunks WHERE inode = ? ORDER BY idx",
    node.inode,
  );
  const parts: Uint8Array[] = [];
  let total = 0;
  for (const chunk of chunks) {
    const row = db.one<{ bytes: Uint8Array }>(
      "SELECT bytes FROM vfs_blob_bytes WHERE hash = ?",
      chunk.hash,
    );
    if (row === undefined) throw new Error("missing blob bytes");
    parts.push(row.bytes);
    total += row.bytes.byteLength;
  }
  const out = new Uint8Array(total);
  let offset = 0;
  for (const part of parts) {
    out.set(part, offset);
    offset += part.byteLength;
  }
  return out;
}

function chunkRows(db: Database, path: string): Array<{ hash: Uint8Array; size: number }> {
  const node = resolveInode(db, path);