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| # encoding: utf-8 | |
| """A fancy version of Python's builtin :func:`dir` function. | |
| """ | |
| # Copyright (c) IPython Development Team. | |
| # Distributed under the terms of the Modified BSD License. | |
| import inspect | |
| import types | |
| def safe_hasattr(obj, attr): | |
| """In recent versions of Python, hasattr() only catches AttributeError. | |
| This catches all errors. | |
| """ | |
| try: | |
| getattr(obj, attr) | |
| return True | |
| except: | |
| return False | |
| def dir2(obj): | |
| """dir2(obj) -> list of strings | |
| Extended version of the Python builtin dir(), which does a few extra | |
| checks. | |
| This version is guaranteed to return only a list of true strings, whereas | |
| dir() returns anything that objects inject into themselves, even if they | |
| are later not really valid for attribute access (many extension libraries | |
| have such bugs). | |
| """ | |
| # Start building the attribute list via dir(), and then complete it | |
| # with a few extra special-purpose calls. | |
| try: | |
| words = set(dir(obj)) | |
| except Exception: | |
| # TypeError: dir(obj) does not return a list | |
| words = set() | |
| if safe_hasattr(obj, '__class__'): | |
| words |= set(dir(obj.__class__)) | |
| # filter out non-string attributes which may be stuffed by dir() calls | |
| # and poor coding in third-party modules | |
| words = [w for w in words if isinstance(w, str)] | |
| return sorted(words) | |
| def get_real_method(obj, name): | |
| """Like getattr, but with a few extra sanity checks: | |
| - If obj is a class, ignore everything except class methods | |
| - Check if obj is a proxy that claims to have all attributes | |
| - Catch attribute access failing with any exception | |
| - Check that the attribute is a callable object | |
| Returns the method or None. | |
| """ | |
| try: | |
| canary = getattr(obj, '_ipython_canary_method_should_not_exist_', None) | |
| except Exception: | |
| return None | |
| if canary is not None: | |
| # It claimed to have an attribute it should never have | |
| return None | |
| try: | |
| m = getattr(obj, name, None) | |
| except Exception: | |
| return None | |
| if inspect.isclass(obj) and not isinstance(m, types.MethodType): | |
| return None | |
| if callable(m): | |
| return m | |
| return None | |