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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright (c) 2017 Cisco and/or its affiliates.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import abc
import copy
import logging
import operator
import types
from netmodel.model.mapper import ObjectSpecification
from netmodel.model.type import is_type
from netmodel.util.meta import inheritors
from netmodel.util.misc import is_iterable
from vicn.core.sa_collections import InstrumentedList, _list_decorators
log = logging.getLogger(__name__)
instance_dict = operator.attrgetter('__dict__')
class NEVER_SET: None
#------------------------------------------------------------------------------
# Attribute Multiplicity
#------------------------------------------------------------------------------
class Multiplicity:
_1_1 = '1_1'
_1_N = '1_N'
_N_1 = 'N_1'
_N_N = 'N_N'
@staticmethod
def reverse(value):
reverse_map = {
Multiplicity._1_1: Multiplicity._1_1,
Multiplicity._1_N: Multiplicity._N_1,
Multiplicity._N_1: Multiplicity._1_N,
Multiplicity._N_N: Multiplicity._N_N,
}
return reverse_map[value]
# Default attribute properties values (default to None)
DEFAULT = {
'multiplicity' : Multiplicity._1_1,
'mandatory' : False,
}
#------------------------------------------------------------------------------
# Attribute
#------------------------------------------------------------------------------
class Attribute(abc.ABC, ObjectSpecification):
properties = [
'name',
'type',
'description',
'default',
'choices',
'mandatory',
'multiplicity',
'ro',
'auto',
'func',
'requirements',
'reverse_name',
'reverse_description',
'reverse_auto'
]
def __init__(self, *args, **kwargs):
for key in Attribute.properties:
value = kwargs.pop(key, NEVER_SET)
setattr(self, key, value)
if len(args) == 1:
self.type, = args
elif len(args) == 2:
self.name, self.type = args
assert is_type(self.type)
self.is_aggregate = False
self._reverse_attributes = list()
#--------------------------------------------------------------------------
# Display
#--------------------------------------------------------------------------
def __repr__(self):
return '<Attribute {}>'.format(self.name)
__str__ = __repr__
#--------------------------------------------------------------------------
# Descriptor protocol
#
# see. https://docs.python.org/3/howto/descriptor.html
#--------------------------------------------------------------------------
def __get__(self, instance, owner=None):
if instance is None:
return self
value = instance_dict(instance).get(self.name, NEVER_SET)
# Case : collection attribute
if self.is_collection:
if value is NEVER_SET:
if isinstance(self.default, types.FunctionType):
default = self.default(instance)
else:
default = self.default
value = InstrumentedList(default)
value._attribute = self
value._instance = instance
self.__set__(instance, value)
return value
return value
# Case : scalar attribute
if value in (None, NEVER_SET) and self.auto not in (None, NEVER_SET):
# Automatic instanciation
if not self.requirements in (None, NEVER_SET) and \
self.requirements:
log.warning('Ignored requirement {}'.format(self.requirements))
value = instance.auto_instanciate(self)
self.__set__(instance, value)
return value
if value is NEVER_SET:
if isinstance(self.default, types.FunctionType):
value = self.default(instance)
else:
value = copy.deepcopy(self.default)
self.__set__(instance, value)
return value
return value
def __set__(self, instance, value):
if instance is None:
return
if self.is_collection:
if not isinstance(value, InstrumentedList):
value = InstrumentedList(value)
value._attribute = self
value._instance = instance
instance_dict(instance)[self.name] = value
if hasattr(instance, '_state'):
instance._state.attr_dirty.add(self.name)
instance._state.dirty = True
def __delete__(self, instance):
raise NotImplementedError
#--------------------------------------------------------------------------
# Accessors
#--------------------------------------------------------------------------
def __getattribute__(self, name):
value = super().__getattribute__(name)
if value is NEVER_SET:
if name == 'default':
return list() if self.is_collection else None
return DEFAULT.get(name, None)
return value
# Shortcuts
def has_reverse_attribute(self):
return self.reverse_name and self.multiplicity
@property
def is_collection(self):
return self.multiplicity in (Multiplicity._1_N, Multiplicity._N_N)
def is_set(self, instance):
return self.name in instance_dict(instance)
#--------------------------------------------------------------------------
# Operations
#--------------------------------------------------------------------------
def merge(self, parent):
for prop in Attribute.properties:
# NOTE: we cannot use getattr otherwise we get the default value,
# and we never override
value = vars(self).get(prop, NEVER_SET)
if value is not NEVER_SET and not is_iterable(value):
continue
parent_value = vars(parent).get(prop, NEVER_SET)
if parent_value is NEVER_SET:
continue
if parent_value:
if is_iterable(value):
value.extend(parent_value)
else:
setattr(self, prop, parent_value)
#--------------------------------------------------------------------------
# Attribute values
#--------------------------------------------------------------------------
def _handle_getitem(self, instance, item):
return item
def _handle_add(self, instance, item):
instance._state.dirty = True
instance._state.attr_dirty.add(self.name)
print('marking', self.name, 'as dirty')
return item
def _handle_remove(self, instance, item):
instance._state.dirty = True
instance._state.attr_dirty.add(self.name)
print('marking', self.name, 'as dirty')
def _handle_before_remove(self, instance):
pass
#--------------------------------------------------------------------------
# Attribute values
#--------------------------------------------------------------------------
class Relation(Attribute):
properties = Attribute.properties[:]
properties.extend([
'reverse_name',
'reverse_description',
'multiplicity',
])
class SelfRelation(Relation):
def __init__(self, *args, **kwargs):
if args:
if not len(args) == 1:
raise ValueError('Bad initialized for SelfRelation')
name, = args
super().__init__(name, None, *args, **kwargs)
else:
super().__init__(None, *args, **kwargs)
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