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Diffstat (limited to 'lib/python2.7/site-packages/south/creator/actions.py')
| -rw-r--r-- | lib/python2.7/site-packages/south/creator/actions.py | 559 |
1 files changed, 559 insertions, 0 deletions
diff --git a/lib/python2.7/site-packages/south/creator/actions.py b/lib/python2.7/site-packages/south/creator/actions.py new file mode 100644 index 0000000..2ffc8ca --- /dev/null +++ b/lib/python2.7/site-packages/south/creator/actions.py @@ -0,0 +1,559 @@ +""" +Actions - things like 'a model was removed' or 'a field was changed'. +Each one has a class, which can take the action description and insert code +blocks into the forwards() and backwards() methods, in the right place. +""" + +from __future__ import print_function + +import sys + +from django.db.models.fields.related import RECURSIVE_RELATIONSHIP_CONSTANT +from django.db.models.fields import FieldDoesNotExist, NOT_PROVIDED, CharField, TextField + +from south.modelsinspector import value_clean +from south.creator.freezer import remove_useless_attributes, model_key +from south.utils import datetime_utils +from south.utils.py3 import raw_input + + +class Action(object): + """ + Generic base Action class. Contains utility methods for inserting into + the forwards() and backwards() method lists. + """ + + prepend_forwards = False + prepend_backwards = False + + def forwards_code(self): + raise NotImplementedError + + def backwards_code(self): + raise NotImplementedError + + def add_forwards(self, forwards): + if self.prepend_forwards: + forwards.insert(0, self.forwards_code()) + else: + forwards.append(self.forwards_code()) + + def add_backwards(self, backwards): + if self.prepend_backwards: + backwards.insert(0, self.backwards_code()) + else: + backwards.append(self.backwards_code()) + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + raise NotImplementedError + + @classmethod + def triples_to_defs(cls, fields): + # Turn the (class, args, kwargs) format into a string + for field, triple in fields.items(): + fields[field] = cls.triple_to_def(triple) + return fields + + @classmethod + def triple_to_def(cls, triple): + "Turns a single triple into a definition." + return "self.gf(%r)(%s)" % ( + triple[0], # Field full path + ", ".join(triple[1] + ["%s=%s" % (kwd, val) for kwd, val in triple[2].items()]), # args and kwds + ) + + +class AddModel(Action): + """ + Addition of a model. Takes the Model subclass that is being created. + """ + + FORWARDS_TEMPLATE = ''' + # Adding model '%(model_name)s' + db.create_table(%(table_name)r, ( + %(field_defs)s + )) + db.send_create_signal(%(app_label)r, [%(model_name)r])'''[1:] + "\n" + + BACKWARDS_TEMPLATE = ''' + # Deleting model '%(model_name)s' + db.delete_table(%(table_name)r)'''[1:] + "\n" + + def __init__(self, model, model_def): + self.model = model + self.model_def = model_def + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " + Added model %s.%s" % ( + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + "Produces the code snippet that gets put into forwards()" + field_defs = ",\n ".join([ + "(%r, %s)" % (name, defn) for name, defn + in self.triples_to_defs(self.model_def).items() + ]) + "," + + return self.FORWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "app_label": self.model._meta.app_label, + "field_defs": field_defs, + } + + def backwards_code(self): + "Produces the code snippet that gets put into backwards()" + return self.BACKWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + } + + +class DeleteModel(AddModel): + """ + Deletion of a model. Takes the Model subclass that is being created. + """ + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " - Deleted model %s.%s" % ( + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + return AddModel.backwards_code(self) + + def backwards_code(self): + return AddModel.forwards_code(self) + + +class _NullIssuesField(object): + """ + A field that might need to ask a question about rogue NULL values. + """ + + issue_with_backward_migration = False + irreversible = False + + IRREVERSIBLE_TEMPLATE = ''' + # User chose to not deal with backwards NULL issues for '%(model_name)s.%(field_name)s' + raise RuntimeError("Cannot reverse this migration. '%(model_name)s.%(field_name)s' and its values cannot be restored.") + + # The following code is provided here to aid in writing a correct migration''' + + def deal_with_not_null_no_default(self, field, field_def): + # If it's a CharField or TextField that's blank, skip this step. + if isinstance(field, (CharField, TextField)) and field.blank: + field_def[2]['default'] = repr("") + return + # Oh dear. Ask them what to do. + print(" ? The field '%s.%s' does not have a default specified, yet is NOT NULL." % ( + self.model._meta.object_name, + field.name, + )) + print(" ? Since you are %s, you MUST specify a default" % self.null_reason) + print(" ? value to use for existing rows. Would you like to:") + print(" ? 1. Quit now"+("." if self.issue_with_backward_migration else ", and add a default to the field in models.py" )) + print(" ? 2. Specify a one-off value to use for existing columns now") + if self.issue_with_backward_migration: + print(" ? 3. Disable the backwards migration by raising an exception; you can edit the migration to fix it later") + while True: + choice = raw_input(" ? Please select a choice: ") + if choice == "1": + sys.exit(1) + elif choice == "2": + break + elif choice == "3" and self.issue_with_backward_migration: + break + else: + print(" ! Invalid choice.") + if choice == "2": + self.add_one_time_default(field, field_def) + elif choice == "3": + self.irreversible = True + + def add_one_time_default(self, field, field_def): + # OK, they want to pick their own one-time default. Who are we to refuse? + print(" ? Please enter Python code for your one-off default value.") + print(" ? The datetime module is available, so you can do e.g. datetime.date.today()") + while True: + code = raw_input(" >>> ") + if not code: + print(" ! Please enter some code, or 'exit' (with no quotes) to exit.") + elif code == "exit": + sys.exit(1) + else: + try: + result = eval(code, {}, {"datetime": datetime_utils}) + except (SyntaxError, NameError) as e: + print(" ! Invalid input: %s" % e) + else: + break + # Right, add the default in. + field_def[2]['default'] = value_clean(result) + + def irreversable_code(self, field): + return self.IRREVERSIBLE_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "field_name": field.name, + "field_column": field.column, + } + + +class AddField(Action, _NullIssuesField): + """ + Adds a field to a model. Takes a Model class and the field name. + """ + + null_reason = "adding this field" + + FORWARDS_TEMPLATE = ''' + # Adding field '%(model_name)s.%(field_name)s' + db.add_column(%(table_name)r, %(field_name)r, + %(field_def)s, + keep_default=False)'''[1:] + "\n" + + BACKWARDS_TEMPLATE = ''' + # Deleting field '%(model_name)s.%(field_name)s' + db.delete_column(%(table_name)r, %(field_column)r)'''[1:] + "\n" + + def __init__(self, model, field, field_def): + self.model = model + self.field = field + self.field_def = field_def + + # See if they've made a NOT NULL column but also have no default (far too common) + is_null = self.field.null + default = (self.field.default is not None) and (self.field.default is not NOT_PROVIDED) + + if not is_null and not default: + self.deal_with_not_null_no_default(self.field, self.field_def) + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " + Added field %s on %s.%s" % ( + self.field.name, + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + + return self.FORWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "field_name": self.field.name, + "field_column": self.field.column, + "field_def": self.triple_to_def(self.field_def), + } + + def backwards_code(self): + return self.BACKWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "field_name": self.field.name, + "field_column": self.field.column, + } + + +class DeleteField(AddField): + """ + Removes a field from a model. Takes a Model class and the field name. + """ + + null_reason = "removing this field" + issue_with_backward_migration = True + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " - Deleted field %s on %s.%s" % ( + self.field.name, + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + return AddField.backwards_code(self) + + def backwards_code(self): + if not self.irreversible: + return AddField.forwards_code(self) + else: + return self.irreversable_code(self.field) + AddField.forwards_code(self) + + +class ChangeField(Action, _NullIssuesField): + """ + Changes a field's type/options on a model. + """ + + null_reason = "making this field non-nullable" + + FORWARDS_TEMPLATE = BACKWARDS_TEMPLATE = ''' + # Changing field '%(model_name)s.%(field_name)s' + db.alter_column(%(table_name)r, %(field_column)r, %(field_def)s)''' + + RENAME_TEMPLATE = ''' + # Renaming column for '%(model_name)s.%(field_name)s' to match new field type. + db.rename_column(%(table_name)r, %(old_column)r, %(new_column)r)''' + + def __init__(self, model, old_field, new_field, old_def, new_def): + self.model = model + self.old_field = old_field + self.new_field = new_field + self.old_def = old_def + self.new_def = new_def + + # See if they've changed a not-null field to be null + new_default = (self.new_field.default is not None) and (self.new_field.default is not NOT_PROVIDED) + old_default = (self.old_field.default is not None) and (self.old_field.default is not NOT_PROVIDED) + if self.old_field.null and not self.new_field.null and not new_default: + self.deal_with_not_null_no_default(self.new_field, self.new_def) + if not self.old_field.null and self.new_field.null and not old_default: + self.null_reason = "making this field nullable" + self.issue_with_backward_migration = True + self.deal_with_not_null_no_default(self.old_field, self.old_def) + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " ~ Changed field %s on %s.%s" % ( + self.new_field.name, + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def _code(self, old_field, new_field, new_def): + + output = "" + + if self.old_field.column != self.new_field.column: + output += self.RENAME_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "field_name": new_field.name, + "old_column": old_field.column, + "new_column": new_field.column, + } + + output += self.FORWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "field_name": new_field.name, + "field_column": new_field.column, + "field_def": self.triple_to_def(new_def), + } + + return output + + def forwards_code(self): + return self._code(self.old_field, self.new_field, self.new_def) + + def backwards_code(self): + change_code = self._code(self.new_field, self.old_field, self.old_def) + if not self.irreversible: + return change_code + else: + return self.irreversable_code(self.old_field) + change_code + + +class AddUnique(Action): + """ + Adds a unique constraint to a model. Takes a Model class and the field names. + """ + + FORWARDS_TEMPLATE = ''' + # Adding unique constraint on '%(model_name)s', fields %(field_names)s + db.create_unique(%(table_name)r, %(fields)r)'''[1:] + "\n" + + BACKWARDS_TEMPLATE = ''' + # Removing unique constraint on '%(model_name)s', fields %(field_names)s + db.delete_unique(%(table_name)r, %(fields)r)'''[1:] + "\n" + + prepend_backwards = True + + def __init__(self, model, fields): + self.model = model + self.fields = fields + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " + Added unique constraint for %s on %s.%s" % ( + [x.name for x in self.fields], + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + + return self.FORWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "fields": [field.column for field in self.fields], + "field_names": [field.name for field in self.fields], + } + + def backwards_code(self): + return self.BACKWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "table_name": self.model._meta.db_table, + "fields": [field.column for field in self.fields], + "field_names": [field.name for field in self.fields], + } + + +class DeleteUnique(AddUnique): + """ + Removes a unique constraint from a model. Takes a Model class and the field names. + """ + + prepend_forwards = True + prepend_backwards = False + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " - Deleted unique constraint for %s on %s.%s" % ( + [x.name for x in self.fields], + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + return AddUnique.backwards_code(self) + + def backwards_code(self): + return AddUnique.forwards_code(self) + + +class AddIndex(AddUnique): + """ + Adds an index to a model field[s]. Takes a Model class and the field names. + """ + + FORWARDS_TEMPLATE = ''' + # Adding index on '%(model_name)s', fields %(field_names)s + db.create_index(%(table_name)r, %(fields)r)'''[1:] + "\n" + + BACKWARDS_TEMPLATE = ''' + # Removing index on '%(model_name)s', fields %(field_names)s + db.delete_index(%(table_name)r, %(fields)r)'''[1:] + "\n" + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " + Added index for %s on %s.%s" % ( + [x.name for x in self.fields], + self.model._meta.app_label, + self.model._meta.object_name, + ) + + +class DeleteIndex(AddIndex): + """ + Deletes an index off a model field[s]. Takes a Model class and the field names. + """ + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " + Deleted index for %s on %s.%s" % ( + [x.name for x in self.fields], + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + return AddIndex.backwards_code(self) + + def backwards_code(self): + return AddIndex.forwards_code(self) + + +class AddM2M(Action): + """ + Adds a unique constraint to a model. Takes a Model class and the field names. + """ + + FORWARDS_TEMPLATE = ''' + # Adding M2M table for field %(field_name)s on '%(model_name)s' + m2m_table_name = %(table_name)s + db.create_table(m2m_table_name, ( + ('id', models.AutoField(verbose_name='ID', primary_key=True, auto_created=True)), + (%(left_field)r, models.ForeignKey(orm[%(left_model_key)r], null=False)), + (%(right_field)r, models.ForeignKey(orm[%(right_model_key)r], null=False)) + )) + db.create_unique(m2m_table_name, [%(left_column)r, %(right_column)r])'''[1:] + "\n" + + BACKWARDS_TEMPLATE = ''' + # Removing M2M table for field %(field_name)s on '%(model_name)s' + db.delete_table(%(table_name)s)'''[1:] + "\n" + + def __init__(self, model, field): + self.model = model + self.field = field + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " + Added M2M table for %s on %s.%s" % ( + self.field.name, + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def table_name(self): + # This is part of a workaround for the fact that Django uses + # different shortening for automatically generated m2m table names + # (as opposed to any explicitly specified table name) + f = self.field + explicit = f.db_table + if explicit: + return "%r" % explicit + else: + auto = "%s_%s" % (self.model._meta.db_table, f.name) + return 'db.shorten_name(%r)' % auto + + def forwards_code(self): + + return self.FORWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "field_name": self.field.name, + "table_name": self.table_name(), + "left_field": self.field.m2m_column_name()[:-3], # Remove the _id part + "left_column": self.field.m2m_column_name(), + "left_model_key": model_key(self.model), + "right_field": self.field.m2m_reverse_name()[:-3], # Remove the _id part + "right_column": self.field.m2m_reverse_name(), + "right_model_key": model_key(self.field.rel.to), + } + + def backwards_code(self): + + return self.BACKWARDS_TEMPLATE % { + "model_name": self.model._meta.object_name, + "field_name": self.field.name, + "table_name": self.table_name(), + } + + +class DeleteM2M(AddM2M): + """ + Adds a unique constraint to a model. Takes a Model class and the field names. + """ + + def console_line(self): + "Returns the string to print on the console, e.g. ' + Added field foo'" + return " - Deleted M2M table for %s on %s.%s" % ( + self.field.name, + self.model._meta.app_label, + self.model._meta.object_name, + ) + + def forwards_code(self): + return AddM2M.backwards_code(self) + + def backwards_code(self): + return AddM2M.forwards_code(self) + |