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Fixed metaclass to handle proxy correctly. Some issues with getting path properties set correctly.

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Griatch 2014-12-20 19:04:49 +01:00
parent 32e44dceab
commit 043ebf7213
6 changed files with 289 additions and 265 deletions
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298
src/typeclasses/models.py
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@ -46,6 +46,7 @@ from src.server.models import ServerConfig
from src.typeclasses import managers
from src.locks.lockhandler import LockHandler
from src.utils import logger
from django.db.models.base import ModelBase
from src.utils.utils import (
make_iter, is_iter, to_str, inherits_from, lazy_property)
from src.utils.dbserialize import to_pickle, from_pickle
@ -739,26 +740,285 @@ class PermissionHandler(TagHandler):
#
#------------------------------------------------------------
# imported for access by other
#from src.utils.idmapper.base import SharedMemoryModelBase
#class TypeclassBase(SharedMemoryModelBase):
# """
# Metaclass which should be set for the root of model proxies
# that don't define any new fields, like Object, Script etc.
# """
# def __new__(cls, name, bases, attrs):
# """
# We must define our Typeclasses as proxies. We also store the path
# directly on the class, this is useful for managers.
# """
# if hasattr(cls, "Meta"):
# cls.Meta.proxy = True
# else:
# class Meta:
# proxy = True
# cls.Meta = Meta
# return super(TypeclassBase, cls).__new__(name, bases, attrs)
#
# Meta class for typeclasses
#
# django patch imports
import copy
from django.apps import apps
from django.db.models.base import subclass_exception
import warnings
from django.db.models.options import Options
from django.utils.deprecation import RemovedInDjango19Warning
from django.core.exceptions import MultipleObjectsReturned
from django.apps.config import MODELS_MODULE_NAME
from django.db.models.fields.related import OneToOneField
#/ django patch imports
from src.utils.idmapper.base import SharedMemoryModelBase
class TypeclassBase(SharedMemoryModelBase):
"""
Metaclass which should be set for the root of model proxies
that don't define any new fields, like Object, Script etc.
"""
def __new__(cls, name, bases, attrs):
"""
We must define our Typeclasses as proxies. We also store the path
directly on the class, this is useful for managers.
"""
# typeclass proxy setup
if "Meta" in attrs:
attrs["Meta"].proxy = True
else:
class Meta:
proxy = True
attrs["Meta"] = Meta
# patch start - django multi-inheritance
# this is a copy of django.db.models.base.__new__
# with a few lines (marked patch below) changed
# as per https://code.djangoproject.com/ticket/11560
super_new = super(ModelBase, cls).__new__
# Also ensure initialization is only performed for subclasses of Model
# (excluding Model class itself).
parents = [b for b in bases if isinstance(b, ModelBase)]
if not parents:
return super_new(cls, name, bases, attrs)
# Create the class.
module = attrs.pop('__module__')
new_class = super_new(cls, name, bases, {'__module__': module})
attr_meta = attrs.pop('Meta', None)
abstract = getattr(attr_meta, 'abstract', False)
if not attr_meta:
meta = getattr(new_class, 'Meta', None)
else:
meta = attr_meta
base_meta = getattr(new_class, '_meta', None)
# Look for an application configuration to attach the model to.
app_config = apps.get_containing_app_config(module)
if getattr(meta, 'app_label', None) is None:
if app_config is None:
# If the model is imported before the configuration for its
# application is created (#21719), or isn't in an installed
# application (#21680), use the legacy logic to figure out the
# app_label by looking one level up from the package or module
# named 'models'. If no such package or module exists, fall
# back to looking one level up from the module this model is
# defined in.
# For 'django.contrib.sites.models', this would be 'sites'.
# For 'geo.models.places' this would be 'geo'.
msg = (
"Model class %s.%s doesn't declare an explicit app_label "
"and either isn't in an application in INSTALLED_APPS or "
"else was imported before its application was loaded. " %
(module, name))
if abstract:
msg += "Its app_label will be set to None in Django 1.9."
else:
msg += "This will no longer be supported in Django 1.9."
warnings.warn(msg, RemovedInDjango19Warning, stacklevel=2)
model_module = sys.modules[new_class.__module__]
package_components = model_module.__name__.split('.')
package_components.reverse() # find the last occurrence of 'models'
try:
app_label_index = package_components.index(MODELS_MODULE_NAME) + 1
except ValueError:
app_label_index = 1
kwargs = {"app_label": package_components[app_label_index]}
else:
kwargs = {"app_label": app_config.label}
else:
kwargs = {}
new_class.add_to_class('_meta', Options(meta, **kwargs))
if not abstract:
new_class.add_to_class(
'DoesNotExist',
subclass_exception(
str('DoesNotExist'),
tuple(x.DoesNotExist for x in parents if hasattr(x, '_meta') and not x._meta.abstract) or (ObjectDoesNotExist,),
module,
attached_to=new_class))
new_class.add_to_class(
'MultipleObjectsReturned',
subclass_exception(
str('MultipleObjectsReturned'),
tuple(x.MultipleObjectsReturned for x in parents if hasattr(x, '_meta') and not x._meta.abstract) or (MultipleObjectsReturned,),
module,
attached_to=new_class))
if base_meta and not base_meta.abstract:
# Non-abstract child classes inherit some attributes from their
# non-abstract parent (unless an ABC comes before it in the
# method resolution order).
if not hasattr(meta, 'ordering'):
new_class._meta.ordering = base_meta.ordering
if not hasattr(meta, 'get_latest_by'):
new_class._meta.get_latest_by = base_meta.get_latest_by
is_proxy = new_class._meta.proxy
# If the model is a proxy, ensure that the base class
# hasn't been swapped out.
if is_proxy and base_meta and base_meta.swapped:
raise TypeError("%s cannot proxy the swapped model '%s'." % (name, base_meta.swapped))
if getattr(new_class, '_default_manager', None):
if not is_proxy:
# Multi-table inheritance doesn't inherit default manager from
# parents.
new_class._default_manager = None
new_class._base_manager = None
else:
# Proxy classes do inherit parent's default manager, if none is
# set explicitly.
new_class._default_manager = new_class._default_manager._copy_to_model(new_class)
new_class._base_manager = new_class._base_manager._copy_to_model(new_class)
# Add all attributes to the class.
for obj_name, obj in attrs.items():
new_class.add_to_class(obj_name, obj)
# All the fields of any type declared on this model
new_fields = (
new_class._meta.local_fields +
new_class._meta.local_many_to_many +
new_class._meta.virtual_fields
)
field_names = set(f.name for f in new_fields)
# Basic setup for proxy models.
if is_proxy:
base = None
for parent in [kls for kls in parents if hasattr(kls, '_meta')]:
if parent._meta.abstract:
if parent._meta.fields:
raise TypeError("Abstract base class containing model fields not permitted for proxy model '%s'." % name)
else:
continue
#if base is not None: # patch
while parent._meta.proxy: # patch
parent = parent._meta.proxy_for_model # patch
if base is not None and base is not parent: # patch
raise TypeError("Proxy model '%s' has more than one non-abstract model base class." % name)
else:
base = parent
if base is None:
raise TypeError("Proxy model '%s' has no non-abstract model base class." % name)
new_class._meta.setup_proxy(base)
new_class._meta.concrete_model = base._meta.concrete_model
else:
new_class._meta.concrete_model = new_class
# Collect the parent links for multi-table inheritance.
parent_links = {}
for base in reversed([new_class] + parents):
# Conceptually equivalent to `if base is Model`.
if not hasattr(base, '_meta'):
continue
# Skip concrete parent classes.
if base != new_class and not base._meta.abstract:
continue
# Locate OneToOneField instances.
for field in base._meta.local_fields:
if isinstance(field, OneToOneField):
parent_links[field.rel.to] = field
# Do the appropriate setup for any model parents.
for base in parents:
original_base = base
if not hasattr(base, '_meta'):
# Things without _meta aren't functional models, so they're
# uninteresting parents.
continue
parent_fields = base._meta.local_fields + base._meta.local_many_to_many
# Check for clashes between locally declared fields and those
# on the base classes (we cannot handle shadowed fields at the
# moment).
for field in parent_fields:
if field.name in field_names:
raise FieldError(
'Local field %r in class %r clashes '
'with field of similar name from '
'base class %r' % (field.name, name, base.__name__)
)
if not base._meta.abstract:
# Concrete classes...
base = base._meta.concrete_model
if base in parent_links:
field = parent_links[base]
elif not is_proxy:
attr_name = '%s_ptr' % base._meta.model_name
field = OneToOneField(base, name=attr_name,
auto_created=True, parent_link=True)
# Only add the ptr field if it's not already present;
# e.g. migrations will already have it specified
if not hasattr(new_class, attr_name):
new_class.add_to_class(attr_name, field)
else:
field = None
new_class._meta.parents[base] = field
else:
# .. and abstract ones.
for field in parent_fields:
new_class.add_to_class(field.name, copy.deepcopy(field))
# Pass any non-abstract parent classes onto child.
new_class._meta.parents.update(base._meta.parents)
# Inherit managers from the abstract base classes.
new_class.copy_managers(base._meta.abstract_managers)
# Proxy models inherit the non-abstract managers from their base,
# unless they have redefined any of them.
if is_proxy:
new_class.copy_managers(original_base._meta.concrete_managers)
# Inherit virtual fields (like GenericForeignKey) from the parent
# class
for field in base._meta.virtual_fields:
if base._meta.abstract and field.name in field_names:
raise FieldError(
'Local field %r in class %r clashes '
'with field of similar name from '
'abstract base class %r' % (field.name, name, base.__name__)
)
new_class.add_to_class(field.name, copy.deepcopy(field))
if abstract:
# Abstract base models can't be instantiated and don't appear in
# the list of models for an app. We do the final setup for them a
# little differently from normal models.
attr_meta.abstract = False
new_class.Meta = attr_meta
return new_class
new_class._prepare()
new_class._meta.apps.register_model(new_class._meta.app_label, new_class)
return new_class
# /patch end
#
# Main TypedObject abstraction
#
class TypedObject(SharedMemoryModel):