source/cffi/_imp_emulation.py

try:
    # this works on Python < 3.12
    from imp import *

except ImportError:
    # this is a limited emulation for Python >= 3.12.
    # Note that this is used only for tests or for the old ffi.verify().
    # This is copied from the source code of Python 3.11.

    from _imp import (acquire_lock, release_lock,
                      is_builtin, is_frozen)

    from importlib._bootstrap import _load

    from importlib import machinery
    import os
    import sys
    import tokenize

    SEARCH_ERROR = 0
    PY_SOURCE = 1
    PY_COMPILED = 2
    C_EXTENSION = 3
    PY_RESOURCE = 4
    PKG_DIRECTORY = 5
    C_BUILTIN = 6
    PY_FROZEN = 7
    PY_CODERESOURCE = 8
    IMP_HOOK = 9

    def get_suffixes():
        extensions = [(s, 'rb', C_EXTENSION)
                      for s in machinery.EXTENSION_SUFFIXES]
        source = [(s, 'r', PY_SOURCE) for s in machinery.SOURCE_SUFFIXES]
        bytecode = [(s, 'rb', PY_COMPILED) for s in machinery.BYTECODE_SUFFIXES]
        return extensions + source + bytecode

    def find_module(name, path=None):
        if not isinstance(name, str):
            raise TypeError("'name' must be a str, not {}".format(type(name)))
        elif not isinstance(path, (type(None), list)):
            # Backwards-compatibility
            raise RuntimeError("'path' must be None or a list, "
                               "not {}".format(type(path)))

        if path is None:
            if is_builtin(name):
                return None, None, ('', '', C_BUILTIN)
            elif is_frozen(name):
                return None, None, ('', '', PY_FROZEN)
            else:
                path = sys.path

        for entry in path:
            package_directory = os.path.join(entry, name)
            for suffix in ['.py', machinery.BYTECODE_SUFFIXES[0]]:
                package_file_name = '__init__' + suffix
                file_path = os.path.join(package_directory, package_file_name)
                if os.path.isfile(file_path):
                    return None, package_directory, ('', '', PKG_DIRECTORY)
            for suffix, mode, type_ in get_suffixes():
                file_name = name + suffix
                file_path = os.path.join(entry, file_name)
                if os.path.isfile(file_path):
                    break
            else:
                continue
            break  # Break out of outer loop when breaking out of inner loop.
        else:
            raise ImportError(name, name=name)

        encoding = None
        if 'b' not in mode:
            with open(file_path, 'rb') as file:
                encoding = tokenize.detect_encoding(file.readline)[0]
        file = open(file_path, mode, encoding=encoding)
        return file, file_path, (suffix, mode, type_)

    def load_dynamic(name, path, file=None):
        loader = machinery.ExtensionFileLoader(name, path)
        spec = machinery.ModuleSpec(name=name, loader=loader, origin=path)
        return _load(spec)