Function readBoundedSource

src/file-limits.ts:53–80

(file: string)

 * past the limit. Returns `bytes: null` for an oversize file.
 */
export async function readBoundedSource(file: string): Promise<BoundedSource> {
  const initial = await fsp.stat(file);
  assertRegularFile(initial);
  if (initial.size > MAX_SOURCE_FILE_SIZE_BYTES) return { stats: initial, bytes: null };
  const handle = await fsp.open(file, 'r');
  try {
    let stats = await handle.stat();
    assertRegularFile(stats);
    if (stats.size > MAX_SOURCE_FILE_SIZE_BYTES) return { stats, bytes: null };
    const chunks: Buffer[] = [];
    let size = 0;
    while (size <= MAX_SOURCE_FILE_SIZE_BYTES) {
      const chunk = Buffer.allocUnsafe(Math.min(READ_CHUNK_BYTES, MAX_SOURCE_FILE_SIZE_BYTES + 1 - size));
      const { bytesRead } = await handle.read(chunk, 0, chunk.length, size);
      if (!bytesRead) break;
      chunks.push(chunk.subarray(0, bytesRead));
      size += bytesRead;
    }
    stats = await handle.stat();
    if (size > MAX_SOURCE_FILE_SIZE_BYTES || stats.size > MAX_SOURCE_FILE_SIZE_BYTES) {
      stats.size = Math.max(size, stats.size);
      return { stats, bytes: null };
    }
    return { stats, bytes: Buffer.concat(chunks, size) };
  } finally {
    await handle.close();
  }
}

/** Synchronous {@link readBoundedSource}. */
export function readBoundedSourceSync(file: string): BoundedSource {