"""
Standardized versions of various cool and/or strange things that you can do
with Python's reflection capabilities.
"""
from __future__ import nested_scopes
import sys
import os
import types
import string
import pickle
import new
def _safe_repr(o):
try:
return repr(o)
except:
try:
return "<%s instance at %s>" % (o.__class__.__name__, id(o))
except:
try:
return "<%s object at %s>" % (type(o).__name__, id(o))
except:
return "<unrepresentable object at %s>" % (id(o),)
try:
import cStringIO as StringIO
except ImportError:
import StringIO
import failure
class Settable:
"""
A mixin class for syntactic sugar. Lets you assign attributes by
calling with keyword arguments; for example, C{x(a=b,c=d,y=z)} is the
same as C{x.a=b;x.c=d;x.y=z}. The most useful place for this is
where you don't want to name a variable, but you do want to set
some attributes; for example, C{X()(y=z,a=b)}.
"""
def __init__(self, **kw):
self(**kw)
def __call__(self,**kw):
for key,val in kw.items():
setattr(self,key,val)
return self
if sys.version_info[:2] >= (2, 2):
type22 = type
else:
class type22: pass
class object: pass
class AccessorType(type22):
"""Metaclass that generates properties automatically.
This is for Python 2.2 and up.
Using this metaclass for your class will give you explicit accessor
methods; a method called set_foo, will automatically create a property
'foo' that uses set_foo as a setter method. Same for get_foo and del_foo.
Note that this will only work on methods that are present on class
creation. If you add methods after the class is defined they will not
automatically become properties. Likewise, class attributes will only
be used if they are present upon class creation, and no getter function
was set - if a getter is present, the class attribute will be ignored.
This is a 2.2-only alternative to the Accessor mixin - just set in your
class definition::
__metaclass__ = AccessorType
"""
def __init__(self, name, bases, d):
type.__init__(self, name, bases, d)
accessors = {}
prefixs = ["get_", "set_", "del_"]
for k in d.keys():
v = getattr(self, k)
for i in range(3):
if k.startswith(prefixs[i]):
accessors.setdefault(k[4:], [None, None, None])[i] = v
for name, (getter, setter, deler) in accessors.items():
if getter is None:
if hasattr(self, name):
value = getattr(self, name)
def getter(this, value=value, name=name):
if this.__dict__.has_key(name):
return this.__dict__[name]
else:
return value
else:
def getter(this, name=name):
if this.__dict__.has_key(name):
return this.__dict__[name]
else:
raise AttributeError, "no such attribute %r" % name
if setter is None:
def setter(this, value, name=name):
this.__dict__[name] = value
if deler is None:
def deler(this, name=name):
del this.__dict__[name]
setattr(self, name, property(getter, setter, deler, ""))
class PropertyAccessor(object):
"""A mixin class for Python 2.2 that uses AccessorType.
This provides compatability with the pre-2.2 Accessor mixin, up
to a point.
Extending this class will give you explicit accessor methods; a
method called set_foo, for example, is the same as an if statement
in __setattr__ looking for 'foo'. Same for get_foo and del_foo.
There are also reallyDel and reallySet methods, so you can
override specifics in subclasses without clobbering __setattr__
and __getattr__, or using non-2.1 compatible code.
There is are incompatibilities with Accessor - accessor
methods added after class creation will *not* be detected. OTOH,
this method is probably way faster.
In addition, class attributes will only be used if no getter
was defined, and instance attributes will not override getter methods
whereas in original Accessor the class attribute or instance attribute
would override the getter method.
"""
__metaclass__ = AccessorType
def reallySet(self, k, v):
self.__dict__[k] = v
def reallyDel(self, k):
del self.__dict__[k]
class Accessor:
"""
Extending this class will give you explicit accessor methods; a
method called C{set_foo}, for example, is the same as an if statement
in L{__setattr__} looking for C{'foo'}. Same for C{get_foo} and
C{del_foo}. There are also L{reallyDel} and L{reallySet} methods,
so you can override specifics in subclasses without clobbering
L{__setattr__} and L{__getattr__}.
This implementation is for Python 2.1.
"""
def __setattr__(self, k,v):
kstring='set_%s'%k
if hasattr(self.__class__,kstring):
return getattr(self,kstring)(v)
else:
self.reallySet(k,v)
def __getattr__(self, k):
kstring='get_%s'%k
if hasattr(self.__class__,kstring):
return getattr(self,kstring)()
raise AttributeError("%s instance has no accessor for: %s" % (qual(self.__class__),k))
def __delattr__(self, k):
kstring='del_%s'%k
if hasattr(self.__class__,kstring):
getattr(self,kstring)()
return
self.reallyDel(k)
def reallySet(self, k,v):
"""
*actually* set self.k to v without incurring side-effects.
This is a hook to be overridden by subclasses.
"""
if k == "__dict__":
self.__dict__.clear()
self.__dict__.update(v)
else:
self.__dict__[k]=v
def reallyDel(self, k):
"""
*actually* del self.k without incurring side-effects. This is a
hook to be overridden by subclasses.
"""
del self.__dict__[k]
OriginalAccessor = Accessor
class Summer(Accessor):
"""
Extend from this class to get the capability to maintain 'related
sums'. Have a tuple in your class like the following::
sums=(('amount','credit','credit_total'),
('amount','debit','debit_total'))
and the 'credit_total' member of the 'credit' member of self will
always be incremented when the 'amount' member of self is
incremented, similiarly for the debit versions.
"""
def reallySet(self, k,v):
"This method does the work."
for sum in self.sums:
attr=sum[0]
obj=sum[1]
objattr=sum[2]
if k == attr:
try:
oldval=getattr(self, attr)
except:
oldval=0
diff=v-oldval
if hasattr(self, obj):
ob=getattr(self,obj)
if ob is not None:
try:oldobjval=getattr(ob, objattr)
except:oldobjval=0.0
setattr(ob,objattr,oldobjval+diff)
elif k == obj:
if hasattr(self, attr):
x=getattr(self,attr)
setattr(self,attr,0)
y=getattr(self,k)
Accessor.reallySet(self,k,v)
setattr(self,attr,x)
Accessor.reallySet(self,y,v)
Accessor.reallySet(self,k,v)
class QueueMethod:
""" I represent a method that doesn't exist yet."""
def __init__(self, name, calls):
self.name = name
self.calls = calls
def __call__(self, *args):
self.calls.append((self.name, args))
def funcinfo(function):
"""
this is more documentation for myself than useful code.
"""
code=function.func_code
name=function.func_name
argc=code.co_argcount
argv=code.co_varnames[:argc]
defaults=function.func_defaults
out = []
out.append('The function %s accepts %s arguments' % (name ,argc))
if defaults:
required=argc-len(defaults)
out.append('It requires %s arguments' % required)
out.append('The arguments required are: %s' % argv[:required])
out.append('additional arguments are:')
for i in range(argc-required):
j=i+required
out.append('%s which has a default of' % (argv[j], defaults[i]))
return out
ISNT=0
WAS=1
IS=2
def fullFuncName(func):
qualName = (str(pickle.whichmodule(func, func.__name__)) + '.' + func.__name__)
if namedObject(qualName) is not func:
raise Exception("Couldn't find %s as %s." % (func, qualName))
return qualName
def qual(clazz):
return clazz.__module__ + '.' + clazz.__name__
def getcurrent(clazz):
assert type(clazz) == types.ClassType, 'must be a class...'
module = namedModule(clazz.__module__)
currclass = getattr(module, clazz.__name__, None)
if currclass is None:
log.msg("Reflection Warning: class %s deleted from module %s" % (
clazz.__name__, clazz.__module__))
return clazz
return currclass
def isinst(inst,clazz):
if type(inst) != types.InstanceType or type(clazz)!=types.ClassType:
return isinstance(inst,clazz)
cl = inst.__class__
cl2 = getcurrent(cl)
clazz = getcurrent(clazz)
if issubclass(cl2,clazz):
if cl == cl2:
return WAS
else:
inst.__class__ = cl2
return IS
else:
return ISNT
def namedModule(name):
"""Return a module given its name."""
topLevel = __import__(name)
packages = name.split(".")[1:]
m = topLevel
for p in packages:
m = getattr(m, p)
return m
def namedObject(name):
"""Get a fully named module-global object.
"""
classSplit = string.split(name, '.')
module = namedModule(string.join(classSplit[:-1], '.'))
return getattr(module, classSplit[-1])
namedClass = namedObject
def namedAny(name):
"""Get a fully named package, module, module-global object, or attribute.
"""
names = name.split('.')
topLevelPackage = None
moduleNames = names[:]
while not topLevelPackage:
try:
trialname = '.'.join(moduleNames)
topLevelPackage = __import__(trialname)
except ImportError:
import traceback
if len(traceback.extract_tb(sys.exc_info()[2])) > 1:
raise
moduleNames.pop()
obj = topLevelPackage
for n in names[1:]:
obj = getattr(obj, n)
return obj
def _reclass(clazz):
clazz = getattr(namedModule(clazz.__module__),clazz.__name__)
clazz.__bases__ = tuple(map(_reclass, clazz.__bases__))
return clazz
def macro(name, filename, source, **identifiers):
"""macro(name, source, **identifiers)
This allows you to create macro-like behaviors in python. See
twisted.python.hook for an example of its usage.
"""
if not identifiers.has_key('name'):
identifiers['name'] = name
source = source % identifiers
codeplace = "<%s (macro)>" % filename
code = compile(source, codeplace, 'exec')
sm = sys.modules
tprm = "twisted.python.reflect.macros"
if not sm.has_key(tprm):
macros = new.module(tprm)
sm[tprm] = macros
macros.count = 0
macros = sm[tprm]
macros.count += 1
macroname = 'macro_' + str(macros.count)
tprmm = tprm + '.' + macroname
mymod = new.module(tprmm)
sys.modules[tprmm] = mymod
setattr(macros, macroname, mymod)
dict = mymod.__dict__
exec code in dict, dict
return dict[name]
def safe_repr(obj):
"""safe_repr(anything) -> string
Returns a string representation of an object (or a traceback, if that
object's __repr__ raised an exception) """
try:
return _safe_repr(obj)
except:
io = StringIO.StringIO()
failure.Failure().printTraceback(file=io)
return "exception in repr!\n"+ io.getvalue()
def allYourBase(classObj, baseClass=None):
"""allYourBase(classObj, baseClass=None) -> list of all base
classes that are subclasses of baseClass, unless it is None,
in which case all bases will be added.
"""
l = []
accumulateBases(classObj, l, baseClass)
return l
def accumulateBases(classObj, l, baseClass=None):
for base in classObj.__bases__:
if baseClass is None or issubclass(base, baseClass):
l.append(base)
accumulateBases(base, l, baseClass)
def prefixedMethodNames(classObj, prefix):
"""A list of method names with a given prefix in a given class.
"""
dct = {}
addMethodNamesToDict(classObj, dct, prefix)
return dct.keys()
def addMethodNamesToDict(classObj, dict, prefix, baseClass=None):
"""
addMethodNamesToDict(classObj, dict, prefix, baseClass=None) -> dict
this goes through 'classObj' (and its bases) and puts method names
starting with 'prefix' in 'dict' with a value of 1. if baseClass isn't
None, methods will only be added if classObj is-a baseClass
If the class in question has the methods 'prefix_methodname' and
'prefix_methodname2', the resulting dict should look something like:
{"methodname": 1, "methodname2": 1}.
"""
for base in classObj.__bases__:
addMethodNamesToDict(base, dict, prefix, baseClass)
if baseClass is None or baseClass in classObj.__bases__:
for name, method in classObj.__dict__.items():
optName = name[len(prefix):]
if ((type(method) is types.FunctionType)
and (name[:len(prefix)] == prefix)
and (len(optName))):
dict[optName] = 1
def prefixedMethods(obj, prefix):
"""A list of methods with a given prefix on a given instance.
"""
dct = {}
accumulateMethods(obj, dct, prefix)
return dct.values()
def accumulateMethods(obj, dict, prefix='', curClass=None):
"""accumulateMethods(instance, dict, prefix)
I recurse through the bases of instance.__class__, and add methods
beginning with 'prefix' to 'dict', in the form of
{'methodname':*instance*method_object}.
"""
if not curClass:
curClass = obj.__class__
for base in curClass.__bases__:
accumulateMethods(obj, dict, prefix, base)
for name, method in curClass.__dict__.items():
optName = name[len(prefix):]
if ((type(method) is types.FunctionType)
and (name[:len(prefix)] == prefix)
and (len(optName))):
dict[optName] = getattr(obj, name)
def accumulateClassDict(classObj, attr, adict, baseClass=None):
"""Accumulate all attributes of a given name in a class heirarchy into a single dictionary.
Assuming all class attributes of this name are dictionaries.
If any of the dictionaries being accumulated have the same key, the
one highest in the class heirarchy wins.
(XXX: If \"higest\" means \"closest to the starting class\".)
Ex::
| class Soy:
| properties = {\"taste\": \"bland\"}
|
| class Plant:
| properties = {\"colour\": \"green\"}
|
| class Seaweed(Plant):
| pass
|
| class Lunch(Soy, Seaweed):
| properties = {\"vegan\": 1 }
|
| dct = {}
|
| accumulateClassDict(Lunch, \"properties\", dct)
|
| print dct
{\"taste\": \"bland\", \"colour\": \"green\", \"vegan\": 1}
"""
for base in classObj.__bases__:
accumulateClassDict(base, attr, adict)
if baseClass is None or baseClass in classObj.__bases__:
adict.update(getattr(classObj, attr, {}))
def accumulateClassList(classObj, attr, listObj, baseClass=None):
"""Accumulate all attributes of a given name in a class heirarchy into a single list.
Assuming all class attributes of this name are lists.
"""
for base in classObj.__bases__:
accumulateClassList(base, attr, listObj)
if baseClass is None or baseClass in classObj.__bases__:
listObj.extend(getattr(classObj, attr, []))
def isSame(a, b):
return (a is b)
def isLike(a, b):
return (a == b)
def modgrep(goal):
return objgrep(sys.modules, goal, isLike, 'sys.modules')
def isOfType(start, goal):
return ((type(start) is goal) or
(isinstance(start, types.InstanceType) and
start.__class__ is goal))
def findInstances(start, t):
return objgrep(start, t, isOfType)
import weakref, re, gc
RegexType = type(re.compile(""))
def objgrep(start, goal, eq=isLike, path='', paths=None, seen=None, showUnknowns=0):
'''An insanely CPU-intensive process for finding stuff.
'''
if paths is None:
paths = []
if seen is None:
seen = {}
if eq(start, goal):
paths.append(path)
if seen.has_key(id(start)):
if seen[id(start)] is start:
return
seen[id(start)] = start
if isinstance(start, types.DictionaryType):
r = []
for k, v in start.items():
objgrep(k, goal, eq, path+'{'+repr(v)+'}', paths, seen)
objgrep(v, goal, eq, path+'['+repr(k)+']', paths, seen)
elif isinstance(start, types.ListType) or isinstance(start, types.TupleType):
for idx in xrange(len(start)):
objgrep(start[idx], goal, eq, path+'['+str(idx)+']', paths, seen)
elif hasattr(start, '__dict__'):
for k, v in start.__dict__.items():
objgrep(v, goal, eq, path+'.'+k, paths, seen)
if isinstance(start, types.InstanceType):
objgrep(start.__class__, goal, eq, path+'.__class__', paths, seen)
elif (isinstance(start, weakref.ProxyTypes + (weakref.ReferenceType,))):
objgrep(start(), goal, eq, path+'()', paths, seen)
elif (isinstance(start, types.StringTypes+
(types.IntType, types.FunctionType, types.MethodType,
types.BuiltinMethodType, RegexType, types.FloatType,
types.NoneType, types.FileType)) or
type(start).__name__ in ('wrapper_descriptor', 'method_descriptor',
'member_descriptor', 'getset_descriptor')):
pass
elif showUnknowns:
print 'unknown type', type(start), start
return paths
def _startswith(s, sub):
return s[:len(sub)] == sub
def filenameToModuleName(fn):
"""Convert a name in the filesystem to the name of the Python module it is.
This is agressive about getting a module name back from a file; it will
always return a string. Agressive means 'sometimes wrong'; it won't look
at the Python path or try to do any error checking: don't use this method
unless you already know that the filename you're talking about is a Python
module.
"""
fullName = os.path.abspath(fn)
modName = os.path.splitext(os.path.basename(fn))[0]
while 1:
fullName = os.path.dirname(fullName)
if os.path.exists(os.path.join(fullName, "__init__.py")):
modName = "%s.%s" % (os.path.basename(fullName), modName)
else:
break
return modName
import log