runpy.py 文件源码

def _get_module_details(mod_name, error=ImportError):
    try:
        loader = get_loader(mod_name)
        if loader is None:
            raise error("No module named %s" % mod_name)
        ispkg = loader.is_package(mod_name)
    except ImportError as e:
        raise error(format(e))
    if ispkg:
        if mod_name == "__main__" or mod_name.endswith(".__main__"):
            raise error("Cannot use package as __main__ module")
        __import__(mod_name)  # Do not catch exceptions initializing package
        try:
            pkg_main_name = mod_name + ".__main__"
            return _get_module_details(pkg_main_name)
        except ImportError, e:
            raise error(("%s; %r is a package and cannot " +
                               "be directly executed") %(e, mod_name))
    try:
        code = loader.get_code(mod_name)
    except ImportError as e:
        raise error(format(e))
    if code is None:
        raise error("No code object available for %s" % mod_name)
    filename = _get_filename(loader, mod_name)
    return mod_name, loader, code, filename