Function _read_directory

Lib/zipimport.py:295–517

(archive)

# Directories can be recognized by the trailing path_sep in the name,
# data_size and file_offset are 0.
def _read_directory(archive):
    try:
        fp = _io.open_code(archive)
    except OSError:
        raise ZipImportError(f"can't open Zip file: {archive!r}", path=archive)

    with fp:
        # GH-87235: On macOS all file descriptors for /dev/fd/N share the same
        # file offset, reset the file offset after scanning the zipfile directory
        # to not cause problems when some runs 'python3 /dev/fd/9 9<some_script'
        start_offset = fp.tell()
        try:
            # Check if there's a comment.
            try:
                fp.seek(0, 2)
                file_size = fp.tell()
            except OSError:
                raise ZipImportError(f"can't read Zip file: {archive!r}",
                                     path=archive)
            max_comment_plus_dirs_size = (
                MAX_COMMENT_LEN + END_CENTRAL_DIR_SIZE +
                END_CENTRAL_DIR_SIZE_64 + END_CENTRAL_DIR_LOCATOR_SIZE_64)
            max_comment_start = max(file_size - max_comment_plus_dirs_size, 0)
            try:
                fp.seek(max_comment_start)
                data = fp.read(max_comment_plus_dirs_size)
            except OSError:
                raise ZipImportError(f"can't read Zip file: {archive!r}",
                                     path=archive)
            pos = data.rfind(STRING_END_ARCHIVE)
            pos64 = data.rfind(STRING_END_ZIP_64)

            if (pos64 >= 0 and pos64+END_CENTRAL_DIR_SIZE_64+END_CENTRAL_DIR_LOCATOR_SIZE_64==pos):
                # Zip64 at "correct" offset from standard EOCD
                buffer = data[pos64:pos64 + END_CENTRAL_DIR_SIZE_64]
                if len(buffer) != END_CENTRAL_DIR_SIZE_64:
                    raise ZipImportError(
                        f"corrupt Zip64 file: Expected {END_CENTRAL_DIR_SIZE_64} byte "
                        f"zip64 central directory, but read {len(buffer)} bytes.",
                        path=archive)
                header_position = file_size - len(data) + pos64

                central_directory_size = _unpack_uint64(buffer[40:48])
                central_directory_position = _unpack_uint64(buffer[48:56])
                num_entries = _unpack_uint64(buffer[24:32])
            elif pos >= 0:
                buffer = data[pos:pos+END_CENTRAL_DIR_SIZE]
                if len(buffer) != END_CENTRAL_DIR_SIZE:
                    raise ZipImportError(f"corrupt Zip file: {archive!r}",
                                         path=archive)

                header_position = file_size - len(data) + pos

                # Buffer now contains a valid EOCD, and header_position gives the
                # starting position of it.
                central_directory_size = _unpack_uint32(buffer[12:16])
                central_directory_position = _unpack_uint32(buffer[16:20])
                num_entries = _unpack_uint16(buffer[8:10])