815602351f
primary keys from character strings to integers, and makes corresponding code changes. This was prompted by database limitations discovered when trying to make DocAlias use a m2m document field; with 255 long strings as primary keys for Document and DocAlias this violated the MySQL database limitations. Changing the primary keys to integers should also improve efficiency. Due to the data migrations which create the new integer primary keys and adds corresponding integer foreign keys matching the previous string foreign keys in all tables having foreign keys to Document and DocAlias, some of these migrations take a long time. The total set of migrations are expected to have a runtime on the order of 2 hours. - Legacy-Id: 16237
103 lines
3.8 KiB
Python
103 lines
3.8 KiB
Python
# Copyright The IETF Trust 2011-2019, All Rights Reserved
|
|
# -*- coding: utf-8 -*-
|
|
|
|
import debug # pyflakes:ignore
|
|
|
|
def find_history_active_at(obj, time):
|
|
"""Assumes obj has a corresponding history model (e.g. obj could
|
|
be Document with a corresponding DocHistory model), then either
|
|
returns the object itself if it was active at time, or the history
|
|
object active at time, or None if time predates the object and its
|
|
history (assuming history is complete).
|
|
|
|
For this to work, the history model must use
|
|
related_name="history_set" for the foreign key connecting to the
|
|
live model, both models must have a "time" DateTimeField and a
|
|
history object must be saved with a copy of the old values and
|
|
old time when the time field changes.
|
|
"""
|
|
if obj.time <= time:
|
|
return obj
|
|
|
|
histories = obj.history_set.order_by('-time')
|
|
|
|
for h in histories:
|
|
if h.time <= time:
|
|
return h
|
|
|
|
return None
|
|
|
|
def find_history_replacements_active_at(objects, time):
|
|
"""Return dictionary mapping object pk to object or its history
|
|
object at the time, if any.
|
|
|
|
Same caveats as for find_history_active_at applies."""
|
|
|
|
if not objects:
|
|
return {}
|
|
|
|
# automatically figure out how to query history model
|
|
history_model = objects[0].history_set.model
|
|
# core_filters contains something like "group__exact": obj
|
|
relation_name = objects[0].history_set.core_filters.keys()[0].replace("__exact", "")
|
|
|
|
# now the querying is a bit tricky - we are only interested in the
|
|
# history version just before time, or if we can't get that, the
|
|
# one just after, but lacking a good way of expressing that
|
|
# through SQL we just grab all of them and sort it out ourselves
|
|
changed_objects = [o for o in objects if o.time > time]
|
|
|
|
histories = history_model.objects.filter(**{ relation_name + "__in": changed_objects }).order_by(relation_name, "-time", "-id")
|
|
|
|
history_for_obj = { o.pk: o for o in objects }
|
|
skip = None
|
|
for h in histories:
|
|
obj_id = getattr(h, relation_name + "_id")
|
|
if obj_id == skip:
|
|
continue
|
|
|
|
history_for_obj[obj_id] = h
|
|
if h.time <= time:
|
|
skip = obj_id # we're far enough, go to next obj
|
|
|
|
return history_for_obj
|
|
|
|
def get_history_object_for(obj):
|
|
"""Construct history object for obj, i.e. instantiate history
|
|
object, copy relevant attributes and set a link to obj, but don't
|
|
save. Any customizations can be done by the caller afterwards.
|
|
Many-to-many fields are not copied (impossible without save).
|
|
|
|
The history model must use related_name="history_set" for the
|
|
foreign key connecting to the live model for this function to be
|
|
able to discover it."""
|
|
|
|
history_model = obj.history_set.model
|
|
h = history_model()
|
|
|
|
# copy attributes shared between history and obj
|
|
history_field_names = set(f.name for f in history_model._meta.fields)
|
|
|
|
for field in obj._meta.fields:
|
|
if field is not obj._meta.pk and field.name in history_field_names:
|
|
setattr(h, field.name, getattr(obj, field.name))
|
|
|
|
# try setting foreign key to obj
|
|
key_name = obj._meta.object_name.lower()
|
|
if key_name in history_field_names:
|
|
setattr(h, key_name, obj)
|
|
|
|
# we can't copy many-to-many fields as h isn't saved yet, leave
|
|
# that to caller
|
|
|
|
return h
|
|
|
|
def copy_many_to_many_for_history(history_obj, obj):
|
|
"""Copy basic many-to-many fields from obj to history_obj."""
|
|
# copy many to many
|
|
for field in obj._meta.many_to_many:
|
|
if field.remote_field.through and field.remote_field.through._meta.auto_created:
|
|
history_field = getattr(history_obj, field.name)
|
|
history_field.clear()
|
|
history_field.set(getattr(obj, field.name).all())
|