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
|
# copyright 2003-2010 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"
from types import MethodType
from time import clock, time
import sys, re
# XXX rewrite so we can use the decorator syntax when keyarg has to be specified
def cached(callableobj, keyarg=None):
"""Simple decorator to cache result of method call."""
if callableobj.func_code.co_argcount == 1 or keyarg == 0:
def cache_wrapper1(self, *args):
cache = '_%s_cache_' % callableobj.__name__
#print 'cache1?', cache
try:
return self.__dict__[cache]
except KeyError:
#print 'miss'
value = callableobj(self, *args)
setattr(self, cache, value)
return value
cache_wrapper1.__doc__ = callableobj.__doc__
return cache_wrapper1
elif keyarg:
def cache_wrapper2(self, *args, **kwargs):
cache = '_%s_cache_' % callableobj.__name__
key = args[keyarg-1]
#print 'cache2?', cache, self, key
try:
_cache = self.__dict__[cache]
except KeyError:
#print 'init'
_cache = {}
setattr(self, cache, _cache)
try:
return _cache[key]
except KeyError:
#print 'miss', self, cache, key
_cache[key] = callableobj(self, *args, **kwargs)
return _cache[key]
cache_wrapper2.__doc__ = callableobj.__doc__
return cache_wrapper2
def cache_wrapper3(self, *args):
cache = '_%s_cache_' % callableobj.__name__
#print 'cache3?', cache, self, args
try:
_cache = self.__dict__[cache]
except KeyError:
#print 'init'
_cache = {}
setattr(self, cache, _cache)
try:
return _cache[args]
except KeyError:
#print 'miss'
_cache[args] = callableobj(self, *args)
return _cache[args]
cache_wrapper3.__doc__ = callableobj.__doc__
return cache_wrapper3
def clear_cache(obj, funcname):
"""Function to clear a cache handled by the cached decorator."""
try:
del obj.__dict__['_%s_cache_' % funcname]
except KeyError:
pass
def copy_cache(obj, funcname, cacheobj):
"""Copy cache for <funcname> from cacheobj to obj."""
cache = '_%s_cache_' % funcname
try:
setattr(obj, cache, cacheobj.__dict__[cache])
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 MethodType(self.func, objtype, objtype.__class__)
return MethodType(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 function
>>> 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):
setattr(klass, methodname or func.__name__, func)
return func
return decorator
|