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# vim: set fenc=utf-8 ft=python sw=4 ts=4 sts=4 et:
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# Copyright 2019, Battelle Memorial Institute.
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import functools
from types import MethodType
import gevent
__all__ = ['annotate', 'annotations', 'dualmethod', 'spawn']
[docs]def annotate(obj, kind, name, value):
# pylint: disable=protected-access
try:
annotations = obj._annotations
except AttributeError:
obj._annotations = annotations = {}
try:
items = annotations[name]
except KeyError:
annotations[name] = items = kind()
assert isinstance(items, kind)
try:
add = items.add
except AttributeError:
try:
add = items.append
except AttributeError:
try:
add = items.update
except AttributeError:
items += value
return
add(value)
[docs]def annotations(obj, kind, name):
# pylint: disable=protected-access
try:
annotations = obj._annotations
except AttributeError:
annotations = {}
try:
items = annotations[name]
except KeyError:
items = kind()
assert isinstance(items, kind)
return items
[docs]def spawn(method):
'''Run a decorated method in its own greenlet, which is returned.'''
@functools.wraps(method)
def wrapper(*args, **kwargs):
return gevent.spawn(method, *args, **kwargs)
return wrapper
[docs]class dualmethod(object):
'''Descriptor to allow class and instance methods of the same name.
This class implements a descriptor that works similar to the
classmethod() built-ins and can be used as a decorator, like the
property() built-in. Instead of a method being only a class or
instance method, two methods can share the same name and be accessed
as an instance method or a class method based on the context.
Example:
>>> class Foo(object):
... @dualmethod
... def bar(self):
... print('instance method for', self)
... @bar.classmethod
... def bar(cls):
... print('class method for', cls)
...
>>> Foo.bar()
class method for <class '__main__.Foo'>
>>> Foo().bar()
instance method for <__main__.Foo object at 0x7fcd744f6610>
>>>
'''
def __init__(self, finstance=None, fclass=None, doc=None):
'''Instantiate the descriptor with the given parameters.
If finstance is set, it must be a method implementing instance
access. If fclass is set, it must be a method implementing class
access similar to a classmethod. If doc is set, it will be used
for the __doc__ attribute. Otherwise, the __doc__ attribute
from the instance or class method will be used, in that order.
'''
self.finstance = finstance
self.fclass = fclass
if doc is not None:
self.__doc__ = doc
elif finstance is not None:
self.__doc__ = finstance.__doc__
elif fclass is not None:
self.__doc__ = fclass.__doc__
def __get__(self, instance, owner):
'''Descriptor getter method.
See Python descriptor documentation.'''
if instance is None:
if self.fclass is None:
if self.finstance is None:
raise AttributeError('no instance or class method is set')
return MethodType(self.finstance, instance)
return MethodType(self.fclass, owner)
if self.finstance is None:
if self.fclass is None:
raise AttributeError('no instance or class method is set')
return MethodType(self.fclass, owner)
return MethodType(self.finstance, instance)
[docs] def instancemethod(self, finstance):
'''Descriptor to set the instance method.'''
self.finstance = finstance
return self
[docs] def classmethod(self, fclass):
'''Descriptor to set the class method.'''
self.fclass = fclass
return self