60 lines
1.8 KiB
Python
60 lines
1.8 KiB
Python
|
from django.core import checks
|
||
|
|
|
||
|
|
NOT_PROVIDED = object()
|
||
|
|
|
||
|
|
|
||
|
|
class FieldCacheMixin:
|
||
|
|
"""Provide an API for working with the model's fields value cache."""
|
||
|
|
|
||
|
|
def get_cache_name(self):
|
||
|
|
raise NotImplementedError
|
||
|
|
|
||
|
|
def get_cached_value(self, instance, default=NOT_PROVIDED):
|
||
|
|
cache_name = self.get_cache_name()
|
||
|
|
try:
|
||
|
|
return instance._state.fields_cache[cache_name]
|
||
|
|
except KeyError:
|
||
|
|
if default is NOT_PROVIDED:
|
||
|
|
raise
|
||
|
|
return default
|
||
|
|
|
||
|
|
def is_cached(self, instance):
|
||
|
|
return self.get_cache_name() in instance._state.fields_cache
|
||
|
|
|
||
|
|
def set_cached_value(self, instance, value):
|
||
|
|
instance._state.fields_cache[self.get_cache_name()] = value
|
||
|
|
|
||
|
|
def delete_cached_value(self, instance):
|
||
|
|
del instance._state.fields_cache[self.get_cache_name()]
|
||
|
|
|
||
|
|
|
||
|
|
class CheckFieldDefaultMixin:
|
||
|
|
_default_hint = ("<valid default>", "<invalid default>")
|
||
|
|
|
||
|
|
def _check_default(self):
|
||
|
|
if (
|
||
|
|
self.has_default()
|
||
|
|
and self.default is not None
|
||
|
|
and not callable(self.default)
|
||
|
|
):
|
||
|
|
return [
|
||
|
|
checks.Warning(
|
||
|
|
"%s default should be a callable instead of an instance "
|
||
|
|
"so that it's not shared between all field instances."
|
||
|
|
% (self.__class__.__name__,),
|
||
|
|
hint=(
|
||
|
|
"Use a callable instead, e.g., use `%s` instead of "
|
||
|
|
"`%s`." % self._default_hint
|
||
|
|
),
|
||
|
|
obj=self,
|
||
|
|
id="fields.E010",
|
||
|
|
)
|
||
|
|
]
|
||
|
|
else:
|
||
|
|
return []
|
||
|
|
|
||
|
|
def check(self, **kwargs):
|
||
|
|
errors = super().check(**kwargs)
|
||
|
|
errors.extend(self._check_default())
|
||
|
|
return errors
|