intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 81 insertions, 0 deletions

diff --git a/contrib/python/ipython/py2/IPython/utils/dir2.py b/contrib/python/ipython/py2/IPython/utils/dir2.py
new file mode 100644
index 0000000000..f6f164f9b1
--- /dev/null
+++ b/contrib/python/ipython/py2/IPython/utils/dir2.py
@@ -0,0 +1,81 @@
+# 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
+from .py3compat import string_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()
+
+    # 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, string_types)]
+    return sorted(words)
+
+
+def get_real_method(obj, name):
+    """Like getattr, but with a few extra sanity checks:
+
+    - If obj is a class, ignore its 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.
+    """
+    if inspect.isclass(obj):
+        return 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 callable(m):
+        return m
+
+    return None