Current File : //usr/lib64/python2.7/site-packages/zope/interface/interface.py
##############################################################################
#
# Copyright (c) 2001, 2002 Zope Foundation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Interface object implementation
"""
from __future__ import generators
import sys
from types import MethodType
from types import FunctionType
import warnings
import weakref
from zope.interface.exceptions import Invalid
from zope.interface.ro import ro
CO_VARARGS = 4
CO_VARKEYWORDS = 8
TAGGED_DATA = '__interface_tagged_values__'
_decorator_non_return = object()
def invariant(call):
f_locals = sys._getframe(1).f_locals
tags = f_locals.setdefault(TAGGED_DATA, {})
invariants = tags.setdefault('invariants', [])
invariants.append(call)
return _decorator_non_return
def taggedValue(key, value):
"""Attaches a tagged value to an interface at definition time."""
f_locals = sys._getframe(1).f_locals
tagged_values = f_locals.setdefault(TAGGED_DATA, {})
tagged_values[key] = value
return _decorator_non_return
class Element(object):
# We can't say this yet because we don't have enough
# infrastructure in place.
#
#implements(IElement)
def __init__(self, __name__, __doc__=''):
"""Create an 'attribute' description
"""
if not __doc__ and __name__.find(' ') >= 0:
__doc__ = __name__
__name__ = None
self.__name__=__name__
self.__doc__=__doc__
self.__tagged_values = {}
def getName(self):
""" Returns the name of the object. """
return self.__name__
def getDoc(self):
""" Returns the documentation for the object. """
return self.__doc__
def getTaggedValue(self, tag):
""" Returns the value associated with 'tag'. """
return self.__tagged_values[tag]
def queryTaggedValue(self, tag, default=None):
""" Returns the value associated with 'tag'. """
return self.__tagged_values.get(tag, default)
def getTaggedValueTags(self):
""" Returns a list of all tags. """
return self.__tagged_values.keys()
def setTaggedValue(self, tag, value):
""" Associates 'value' with 'key'. """
self.__tagged_values[tag] = value
class SpecificationBasePy(object):
def providedBy(self, ob):
"""Is the interface implemented by an object
"""
spec = providedBy(ob)
return self in spec._implied
def implementedBy(self, cls):
"""Test whether the specification is implemented by a class or factory.
Raise TypeError if argument is neither a class nor a callable.
"""
spec = implementedBy(cls)
return self in spec._implied
def isOrExtends(self, interface):
"""Is the interface the same as or extend the given interface
"""
return interface in self._implied
__call__ = isOrExtends
SpecificationBase = SpecificationBasePy
try:
from _zope_interface_coptimizations import SpecificationBase
except ImportError: #pragma NO COVER
pass
_marker = object()
class InterfaceBasePy(object):
"""Base class that wants to be replaced with a C base :)
"""
def __call__(self, obj, alternate=_marker):
"""Adapt an object to the interface
"""
conform = getattr(obj, '__conform__', None)
if conform is not None:
adapter = self._call_conform(conform)
if adapter is not None:
return adapter
adapter = self.__adapt__(obj)
if adapter is not None:
return adapter
elif alternate is not _marker:
return alternate
else:
raise TypeError("Could not adapt", obj, self)
def __adapt__(self, obj):
"""Adapt an object to the reciever
"""
if self.providedBy(obj):
return obj
for hook in adapter_hooks:
adapter = hook(self, obj)
if adapter is not None:
return adapter
InterfaceBase = InterfaceBasePy
try:
from _zope_interface_coptimizations import InterfaceBase
except ImportError: #pragma NO COVER
pass
adapter_hooks = []
try:
from _zope_interface_coptimizations import adapter_hooks
except ImportError: #pragma NO COVER
pass
class Specification(SpecificationBase):
"""Specifications
An interface specification is used to track interface declarations
and component registrations.
This class is a base class for both interfaces themselves and for
interface specifications (declarations).
Specifications are mutable. If you reassign their bases, their
relations with other specifications are adjusted accordingly.
"""
# Copy some base class methods for speed
isOrExtends = SpecificationBase.isOrExtends
providedBy = SpecificationBase.providedBy
def __init__(self, bases=()):
self._implied = {}
self.dependents = weakref.WeakKeyDictionary()
self.__bases__ = tuple(bases)
def subscribe(self, dependent):
self.dependents[dependent] = self.dependents.get(dependent, 0) + 1
def unsubscribe(self, dependent):
n = self.dependents.get(dependent, 0) - 1
if not n:
del self.dependents[dependent]
elif n > 0:
self.dependents[dependent] = n
else:
raise KeyError(dependent)
def __setBases(self, bases):
# Register ourselves as a dependent of our old bases
for b in self.__bases__:
b.unsubscribe(self)
# Register ourselves as a dependent of our bases
self.__dict__['__bases__'] = bases
for b in bases:
b.subscribe(self)
self.changed(self)
__bases__ = property(
lambda self: self.__dict__.get('__bases__', ()),
__setBases,
)
def changed(self, originally_changed):
"""We, or something we depend on, have changed
"""
try:
del self._v_attrs
except AttributeError:
pass
implied = self._implied
implied.clear()
ancestors = ro(self)
try:
if Interface not in ancestors:
ancestors.append(Interface)
except NameError:
pass # defining Interface itself
self.__sro__ = tuple(ancestors)
self.__iro__ = tuple([ancestor for ancestor in ancestors
if isinstance(ancestor, InterfaceClass)
])
for ancestor in ancestors:
# We directly imply our ancestors:
implied[ancestor] = ()
# Now, advise our dependents of change:
for dependent in tuple(self.dependents.keys()):
dependent.changed(originally_changed)
def interfaces(self):
"""Return an iterator for the interfaces in the specification.
"""
seen = {}
for base in self.__bases__:
for interface in base.interfaces():
if interface not in seen:
seen[interface] = 1
yield interface
def extends(self, interface, strict=True):
"""Does the specification extend the given interface?
Test whether an interface in the specification extends the
given interface
"""
return ((interface in self._implied)
and
((not strict) or (self != interface))
)
def weakref(self, callback=None):
return weakref.ref(self, callback)
def get(self, name, default=None):
"""Query for an attribute description
"""
try:
attrs = self._v_attrs
except AttributeError:
attrs = self._v_attrs = {}
attr = attrs.get(name)
if attr is None:
for iface in self.__iro__:
attr = iface.direct(name)
if attr is not None:
attrs[name] = attr
break
if attr is None:
return default
else:
return attr
class InterfaceClass(Element, InterfaceBase, Specification):
"""Prototype (scarecrow) Interfaces Implementation."""
# We can't say this yet because we don't have enough
# infrastructure in place.
#
#implements(IInterface)
def __init__(self, name, bases=(), attrs=None, __doc__=None,
__module__=None):
if attrs is None:
attrs = {}
if __module__ is None:
__module__ = attrs.get('__module__')
if isinstance(__module__, str):
del attrs['__module__']
else:
try:
# Figure out what module defined the interface.
# This is how cPython figures out the module of
# a class, but of course it does it in C. :-/
__module__ = sys._getframe(1).f_globals['__name__']
except (AttributeError, KeyError): #pragma NO COVERAGE
pass
self.__module__ = __module__
d = attrs.get('__doc__')
if d is not None:
if not isinstance(d, Attribute):
if __doc__ is None:
__doc__ = d
del attrs['__doc__']
if __doc__ is None:
__doc__ = ''
Element.__init__(self, name, __doc__)
tagged_data = attrs.pop(TAGGED_DATA, None)
if tagged_data is not None:
for key, val in tagged_data.items():
self.setTaggedValue(key, val)
for base in bases:
if not isinstance(base, InterfaceClass):
raise TypeError('Expected base interfaces')
Specification.__init__(self, bases)
# Make sure that all recorded attributes (and methods) are of type
# `Attribute` and `Method`
for name, attr in list(attrs.items()):
if name in ('__locals__', '__qualname__'):
# __locals__: Python 3 sometimes adds this.
# __qualname__: PEP 3155 (Python 3.3+)
del attrs[name]
continue
if isinstance(attr, Attribute):
attr.interface = self
if not attr.__name__:
attr.__name__ = name
elif isinstance(attr, FunctionType):
attrs[name] = fromFunction(attr, self, name=name)
elif attr is _decorator_non_return:
del attrs[name]
else:
raise InvalidInterface("Concrete attribute, " + name)
self.__attrs = attrs
self.__identifier__ = "%s.%s" % (self.__module__, self.__name__)
def interfaces(self):
"""Return an iterator for the interfaces in the specification.
"""
yield self
def getBases(self):
return self.__bases__
def isEqualOrExtendedBy(self, other):
"""Same interface or extends?"""
return self == other or other.extends(self)
def names(self, all=False):
"""Return the attribute names defined by the interface."""
if not all:
return self.__attrs.keys()
r = self.__attrs.copy()
for base in self.__bases__:
r.update(dict.fromkeys(base.names(all)))
return r.keys()
def __iter__(self):
return iter(self.names(all=True))
def namesAndDescriptions(self, all=False):
"""Return attribute names and descriptions defined by interface."""
if not all:
return self.__attrs.items()
r = {}
for base in self.__bases__[::-1]:
r.update(dict(base.namesAndDescriptions(all)))
r.update(self.__attrs)
return r.items()
def getDescriptionFor(self, name):
"""Return the attribute description for the given name."""
r = self.get(name)
if r is not None:
return r
raise KeyError(name)
__getitem__ = getDescriptionFor
def __contains__(self, name):
return self.get(name) is not None
def direct(self, name):
return self.__attrs.get(name)
def queryDescriptionFor(self, name, default=None):
return self.get(name, default)
def deferred(self):
"""Return a defered class corresponding to the interface."""
if hasattr(self, "_deferred"): return self._deferred
klass={}
exec("class %s: pass" % self.__name__, klass)
klass=klass[self.__name__]
self.__d(klass)
self._deferred=klass
return klass
def validateInvariants(self, obj, errors=None):
"""validate object to defined invariants."""
for call in self.queryTaggedValue('invariants', []):
try:
call(obj)
except Invalid as e:
if errors is None:
raise
else:
errors.append(e)
for base in self.__bases__:
try:
base.validateInvariants(obj, errors)
except Invalid:
if errors is None:
raise
if errors:
raise Invalid(errors)
#XXX I believe this is a fossil: nobody calls it anywhere.
#def _getInterface(self, ob, name):
# """Retrieve a named interface."""
# return None
def __d(self, klass):
for k, v in self.__attrs.items():
if isinstance(v, Method) and not (k in klass.__dict__):
setattr(klass, k, v)
for b in self.__bases__:
b.__d(klass)
def __repr__(self):
try:
return self._v_repr
except AttributeError:
name = self.__name__
m = self.__module__
if m:
name = '%s.%s' % (m, name)
r = "<%s %s>" % (self.__class__.__name__, name)
self._v_repr = r
return r
def _call_conform(self, conform):
try:
return conform(self)
except TypeError: #pragma NO COVER
# We got a TypeError. It might be an error raised by
# the __conform__ implementation, or *we* may have
# made the TypeError by calling an unbound method
# (object is a class). In the later case, we behave
# as though there is no __conform__ method. We can
# detect this case by checking whether there is more
# than one traceback object in the traceback chain:
if sys.exc_info()[2].tb_next is not None:
# There is more than one entry in the chain, so
# reraise the error:
raise
# This clever trick is from Phillip Eby
return None #pragma NO COVER
def __reduce__(self):
return self.__name__
def __cmp(self, other):
# Yes, I did mean to name this __cmp, rather than __cmp__.
# It is a private method used by __lt__ and __gt__.
# I don't want to override __eq__ because I want the default
# __eq__, which is really fast.
"""Make interfaces sortable
TODO: It would ne nice if:
More specific interfaces should sort before less specific ones.
Otherwise, sort on name and module.
But this is too complicated, and we're going to punt on it
for now.
For now, sort on interface and module name.
None is treated as a pseudo interface that implies the loosest
contact possible, no contract. For that reason, all interfaces
sort before None.
"""
if other is None:
return -1
n1 = (getattr(self, '__name__', ''), getattr(self, '__module__', ''))
n2 = (getattr(other, '__name__', ''), getattr(other, '__module__', ''))
# This spelling works under Python3, which doesn't have cmp().
return (n1 > n2) - (n1 < n2)
def __hash__(self):
d = self.__dict__
if '__module__' not in d or '__name__' not in d: #pragma NO COVER
warnings.warn('Hashing uninitialized InterfaceClass instance')
return 1
return hash((self.__name__, self.__module__))
def __eq__(self, other):
c = self.__cmp(other)
return c == 0
def __ne__(self, other):
c = self.__cmp(other)
return c != 0
def __lt__(self, other):
c = self.__cmp(other)
return c < 0
def __le__(self, other):
c = self.__cmp(other)
return c <= 0
def __gt__(self, other):
c = self.__cmp(other)
return c > 0
def __ge__(self, other):
c = self.__cmp(other)
return c >= 0
Interface = InterfaceClass("Interface", __module__ = 'zope.interface')
class Attribute(Element):
"""Attribute descriptions
"""
# We can't say this yet because we don't have enough
# infrastructure in place.
#
# implements(IAttribute)
interface = None
class Method(Attribute):
"""Method interfaces
The idea here is that you have objects that describe methods.
This provides an opportunity for rich meta-data.
"""
# We can't say this yet because we don't have enough
# infrastructure in place.
#
# implements(IMethod)
positional = required = ()
_optional = varargs = kwargs = None
def _get_optional(self):
if self._optional is None:
return {}
return self._optional
def _set_optional(self, opt):
self._optional = opt
def _del_optional(self):
self._optional = None
optional = property(_get_optional, _set_optional, _del_optional)
def __call__(self, *args, **kw):
raise BrokenImplementation(self.interface, self.__name__)
def getSignatureInfo(self):
return {'positional': self.positional,
'required': self.required,
'optional': self.optional,
'varargs': self.varargs,
'kwargs': self.kwargs,
}
def getSignatureString(self):
sig = []
for v in self.positional:
sig.append(v)
if v in self.optional.keys():
sig[-1] += "=" + repr(self.optional[v])
if self.varargs:
sig.append("*" + self.varargs)
if self.kwargs:
sig.append("**" + self.kwargs)
return "(%s)" % ", ".join(sig)
def fromFunction(func, interface=None, imlevel=0, name=None):
name = name or func.__name__
method = Method(name, func.__doc__)
defaults = getattr(func, '__defaults__', None) or ()
code = func.__code__
# Number of positional arguments
na = code.co_argcount-imlevel
names = code.co_varnames[imlevel:]
opt = {}
# Number of required arguments
nr = na-len(defaults)
if nr < 0:
defaults=defaults[-nr:]
nr = 0
# Determine the optional arguments.
opt.update(dict(zip(names[nr:], defaults)))
method.positional = names[:na]
method.required = names[:nr]
method.optional = opt
argno = na
# Determine the function's variable argument's name (i.e. *args)
if code.co_flags & CO_VARARGS:
method.varargs = names[argno]
argno = argno + 1
else:
method.varargs = None
# Determine the function's keyword argument's name (i.e. **kw)
if code.co_flags & CO_VARKEYWORDS:
method.kwargs = names[argno]
else:
method.kwargs = None
method.interface = interface
for key, value in func.__dict__.items():
method.setTaggedValue(key, value)
return method
def fromMethod(meth, interface=None, name=None):
if isinstance(meth, MethodType):
func = meth.__func__
else:
func = meth
return fromFunction(func, interface, imlevel=1, name=name)
# Now we can create the interesting interfaces and wire them up:
def _wire():
from zope.interface.declarations import classImplements
from zope.interface.interfaces import IAttribute
classImplements(Attribute, IAttribute)
from zope.interface.interfaces import IMethod
classImplements(Method, IMethod)
from zope.interface.interfaces import IInterface
classImplements(InterfaceClass, IInterface)
from zope.interface.interfaces import ISpecification
classImplements(Specification, ISpecification)
# We import this here to deal with module dependencies.
from zope.interface.declarations import implementedBy
from zope.interface.declarations import providedBy
from zope.interface.exceptions import InvalidInterface
from zope.interface.exceptions import BrokenImplementation
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