/usr/lib/python2.7/dist-packages/logilab/common/decorators.py is in python-logilab-common 0.62.0-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 | # copyright 2003-2013 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of logilab-common.
#
# logilab-common is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option) any
# later version.
#
# logilab-common is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License along
# with logilab-common. If not, see <http://www.gnu.org/licenses/>.
""" A few useful function/method decorators. """
__docformat__ = "restructuredtext en"
import sys
import types
from time import clock, time
from logilab.common.compat import callable, method_type
# XXX rewrite so we can use the decorator syntax when keyarg has to be specified
def _is_generator_function(callableobj):
return callableobj.func_code.co_flags & 0x20
class cached_decorator(object):
def __init__(self, cacheattr=None, keyarg=None):
self.cacheattr = cacheattr
self.keyarg = keyarg
def __call__(self, callableobj=None):
assert not _is_generator_function(callableobj), \
'cannot cache generator function: %s' % callableobj
if callableobj.func_code.co_argcount == 1 or self.keyarg == 0:
cache = _SingleValueCache(callableobj, self.cacheattr)
elif self.keyarg:
cache = _MultiValuesKeyArgCache(callableobj, self.keyarg, self.cacheattr)
else:
cache = _MultiValuesCache(callableobj, self.cacheattr)
return cache.closure()
class _SingleValueCache(object):
def __init__(self, callableobj, cacheattr=None):
self.callable = callableobj
if cacheattr is None:
self.cacheattr = '_%s_cache_' % callableobj.__name__
else:
assert cacheattr != callableobj.__name__
self.cacheattr = cacheattr
def __call__(__me, self, *args):
try:
return self.__dict__[__me.cacheattr]
except KeyError:
value = __me.callable(self, *args)
setattr(self, __me.cacheattr, value)
return value
def closure(self):
def wrapped(*args, **kwargs):
return self.__call__(*args, **kwargs)
wrapped.cache_obj = self
try:
wrapped.__doc__ = self.callable.__doc__
wrapped.__name__ = self.callable.__name__
wrapped.func_name = self.callable.func_name
except:
pass
return wrapped
def clear(self, holder):
holder.__dict__.pop(self.cacheattr, None)
class _MultiValuesCache(_SingleValueCache):
def _get_cache(self, holder):
try:
_cache = holder.__dict__[self.cacheattr]
except KeyError:
_cache = {}
setattr(holder, self.cacheattr, _cache)
return _cache
def __call__(__me, self, *args, **kwargs):
_cache = __me._get_cache(self)
try:
return _cache[args]
except KeyError:
_cache[args] = __me.callable(self, *args)
return _cache[args]
class _MultiValuesKeyArgCache(_MultiValuesCache):
def __init__(self, callableobj, keyarg, cacheattr=None):
super(_MultiValuesKeyArgCache, self).__init__(callableobj, cacheattr)
self.keyarg = keyarg
def __call__(__me, self, *args, **kwargs):
_cache = __me._get_cache(self)
key = args[__me.keyarg-1]
try:
return _cache[key]
except KeyError:
_cache[key] = __me.callable(self, *args, **kwargs)
return _cache[key]
def cached(callableobj=None, keyarg=None, **kwargs):
"""Simple decorator to cache result of method call."""
kwargs['keyarg'] = keyarg
decorator = cached_decorator(**kwargs)
if callableobj is None:
return decorator
else:
return decorator(callableobj)
class cachedproperty(object):
""" Provides a cached property equivalent to the stacking of
@cached and @property, but more efficient.
After first usage, the <property_name> becomes part of the object's
__dict__. Doing:
del obj.<property_name> empties the cache.
Idea taken from the pyramid_ framework and the mercurial_ project.
.. _pyramid: http://pypi.python.org/pypi/pyramid
.. _mercurial: http://pypi.python.org/pypi/Mercurial
"""
__slots__ = ('wrapped',)
def __init__(self, wrapped):
try:
wrapped.__name__
except AttributeError:
raise TypeError('%s must have a __name__ attribute' %
wrapped)
self.wrapped = wrapped
@property
def __doc__(self):
doc = getattr(self.wrapped, '__doc__', None)
return ('<wrapped by the cachedproperty decorator>%s'
% ('\n%s' % doc if doc else ''))
def __get__(self, inst, objtype=None):
if inst is None:
return self
val = self.wrapped(inst)
setattr(inst, self.wrapped.__name__, val)
return val
def get_cache_impl(obj, funcname):
cls = obj.__class__
member = getattr(cls, funcname)
if isinstance(member, property):
member = member.fget
return member.cache_obj
def clear_cache(obj, funcname):
"""Clear a cache handled by the :func:`cached` decorator. If 'x' class has
@cached on its method `foo`, type
>>> clear_cache(x, 'foo')
to purge this method's cache on the instance.
"""
get_cache_impl(obj, funcname).clear(obj)
def copy_cache(obj, funcname, cacheobj):
"""Copy cache for <funcname> from cacheobj to obj."""
cacheattr = get_cache_impl(obj, funcname).cacheattr
try:
setattr(obj, cacheattr, cacheobj.__dict__[cacheattr])
except KeyError:
pass
class wproperty(object):
"""Simple descriptor expecting to take a modifier function as first argument
and looking for a _<function name> to retrieve the attribute.
"""
def __init__(self, setfunc):
self.setfunc = setfunc
self.attrname = '_%s' % setfunc.__name__
def __set__(self, obj, value):
self.setfunc(obj, value)
def __get__(self, obj, cls):
assert obj is not None
return getattr(obj, self.attrname)
class classproperty(object):
"""this is a simple property-like class but for class attributes.
"""
def __init__(self, get):
self.get = get
def __get__(self, inst, cls):
return self.get(cls)
class iclassmethod(object):
'''Descriptor for method which should be available as class method if called
on the class or instance method if called on an instance.
'''
def __init__(self, func):
self.func = func
def __get__(self, instance, objtype):
if instance is None:
return method_type(self.func, objtype, objtype.__class__)
return method_type(self.func, instance, objtype)
def __set__(self, instance, value):
raise AttributeError("can't set attribute")
def timed(f):
def wrap(*args, **kwargs):
t = time()
c = clock()
res = f(*args, **kwargs)
print '%s clock: %.9f / time: %.9f' % (f.__name__,
clock() - c, time() - t)
return res
return wrap
def locked(acquire, release):
"""Decorator taking two methods to acquire/release a lock as argument,
returning a decorator function which will call the inner method after
having called acquire(self) et will call release(self) afterwards.
"""
def decorator(f):
def wrapper(self, *args, **kwargs):
acquire(self)
try:
return f(self, *args, **kwargs)
finally:
release(self)
return wrapper
return decorator
def monkeypatch(klass, methodname=None):
"""Decorator extending class with the decorated callable. This is basically
a syntactic sugar vs class assignment.
>>> class A:
... pass
>>> @monkeypatch(A)
... def meth(self):
... return 12
...
>>> a = A()
>>> a.meth()
12
>>> @monkeypatch(A, 'foo')
... def meth(self):
... return 12
...
>>> a.foo()
12
"""
def decorator(func):
try:
name = methodname or func.__name__
except AttributeError:
raise AttributeError('%s has no __name__ attribute: '
'you should provide an explicit `methodname`'
% func)
setattr(klass, name, func)
return func
return decorator
|