Function _read_directory

tools/python-3.11.9-amd64/Lib/zipimport.py:401–524

(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 diretory
        # to not cause problems when some runs 'python3 /dev/fd/9 9<some_script'
        start_offset = fp.tell()
        try:
            try:
                fp.seek(-END_CENTRAL_DIR_SIZE, 2)
                header_position = fp.tell()
                buffer = fp.read(END_CENTRAL_DIR_SIZE)
            except OSError:
                raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
            if len(buffer) != END_CENTRAL_DIR_SIZE:
                raise ZipImportError(f"can't read Zip file: {archive!r}", path=archive)
            if buffer[:4] != STRING_END_ARCHIVE:
                # Bad: End of Central Dir signature
                # 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_start = max(file_size - MAX_COMMENT_LEN -
                                        END_CENTRAL_DIR_SIZE, 0)
                try:
                    fp.seek(max_comment_start)
                    data = fp.read()
                except OSError:
                    raise ZipImportError(f"can't read Zip file: {archive!r}",
                                         path=archive)
                pos = data.rfind(STRING_END_ARCHIVE)
                if pos < 0:
                    raise ZipImportError(f'not a Zip file: {archive!r}',
                                         path=archive)
                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

            header_size = _unpack_uint32(buffer[12:16])
            header_offset = _unpack_uint32(buffer[16:20])
            if header_position < header_size:
                raise ZipImportError(f'bad central directory size: {archive!r}', path=archive)
            if header_position < header_offset:
                raise ZipImportError(f'bad central directory offset: {archive!r}', path=archive)
            header_position -= header_size
            arc_offset = header_position - header_offset
            if arc_offset < 0:
                raise ZipImportError(f'bad central directory size or offset: {archive!r}', path=archive)