1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
Simple utility functions and bug fixes for compatibility with all supported
versions of Python. This module should generally not be used directly, as
everything in `__all__` will be imported into `astropy.utils.compat` and can
be accessed from there.
Includes the following fixes:
* The `contextlib.suppress` context manager, which is only available in Python
3.4 or greater.
"""
from __future__ import (absolute_import, division, print_function,
unicode_literals)
from ...extern import six
import functools
import sys
from ..decorators import deprecated
__all__ = ['invalidate_caches', 'override__dir__', 'suppress',
'possible_filename', 'namedtuple_asdict']
def possible_filename(filename):
"""
Determine if the ``filename`` argument is an allowable type for a filename.
In Python 3.3 use of non-unicode filenames on system calls such as
`os.stat` and others that accept a filename argument was deprecated (and
may be removed outright in the future).
Therefore this returns `True` in all cases except for `bytes` strings in
Windows on Python >= 3.3.
"""
if isinstance(filename, six.text_type):
return True
elif isinstance(filename, six.binary_type):
return not (sys.platform == 'win32' and
sys.version_info[:2] >= (3, 3))
return False
# Python 3.3's importlib caches filesystem reads for faster imports in the
# general case. But sometimes it's necessary to manually invalidate those
# caches so that the import system can pick up new generated files. See
# https://github.com/astropy/astropy/issues/820
if sys.version_info[:2] >= (3, 3):
from importlib import invalidate_caches
else:
invalidate_caches = lambda: None
def override__dir__(f):
"""
When overriding a __dir__ method on an object, you often want to
include the "standard" members on the object as well. This
decorator takes care of that automatically, and all the wrapped
function needs to do is return a list of the "special" members
that wouldn't be found by the normal Python means.
Example
-------
@override__dir__
def __dir__(self):
return ['special_method1', 'special_method2']
"""
if sys.version_info[:2] < (3, 3):
# There was no straightforward way to do this until Python 3.3, so
# we have this complex monstrosity
@functools.wraps(f)
def override__dir__wrapper(self):
members = set()
for cls in self.__class__.mro():
members.update(dir(cls))
members.update(six.iterkeys(self.__dict__))
members.update(f(self))
return sorted(members)
else:
# http://bugs.python.org/issue12166
@functools.wraps(f)
def override__dir__wrapper(self):
members = set(object.__dir__(self))
members.update(f(self))
return sorted(members)
return override__dir__wrapper
try:
from contextlib import ignored
except ImportError:
from contextlib import contextmanager
@deprecated('1.3', alternative='suppress')
@contextmanager
def ignored(*exceptions):
"""A context manager for ignoring exceptions. Equivalent to::
try:
<body>
except exceptions:
pass
Example::
>>> import os
>>> with ignored(OSError):
... os.remove('file-that-does-not-exist')
"""
try:
yield
except exceptions:
pass
try:
from contextlib import suppress
except ImportError:
from contextlib import contextmanager
@contextmanager
def suppress(*exceptions):
"""A context manager for ignoring exceptions. Equivalent to::
try:
<body>
except exceptions:
pass
Example::
>>> import os
>>> with suppress(OSError):
... os.remove('file-that-does-not-exist')
"""
try:
yield
except exceptions:
pass
# For unclear reasons, the `_asdict` method of namedtuple produces an empty
# dictionary if the namedtuple is a subclass of another namedtuple... But
# *only* in py 3.3. >3.4 or 2.7 seem to work just fine. So we provide this
# for compatibility as long as 3.3 is supported.
# Furthermore, in python 3.4.x except for 3.4.4, `_asdict` produces only a
# *partial* dictionary. So we work around that case too.
if sys.version_info[0] == 3 and sys.version_info[:3] < (3, 4, 4):
def namedtuple_asdict(namedtuple):
"""
The same as ``namedtuple._adict()``, but fixed to work even when
namedtuple is a subclass of another namedtuple
Parameters
----------
namedtuple : collections.namedtuple
The named tuple to get the dict of
"""
return {fi:getattr(namedtuple, fi) for fi in namedtuple._fields}
else:
def namedtuple_asdict(namedtuple):
"""
The same as ``namedtuple._adict()``.
Parameters
----------
namedtuple : collections.namedtuple
The named tuple to get the dict of
"""
return namedtuple._asdict()
|
