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