start-pack

myenv/lib/python3.12/site-packages/django/db/models/fields/composite.py

@@ -0,0 +1,177 @@
+import json
+
+from django.core import checks
+from django.db.models import NOT_PROVIDED, Field
+from django.db.models.expressions import ColPairs
+from django.db.models.fields.tuple_lookups import (
+    TupleExact,
+    TupleGreaterThan,
+    TupleGreaterThanOrEqual,
+    TupleIn,
+    TupleIsNull,
+    TupleLessThan,
+    TupleLessThanOrEqual,
+)
+from django.utils.functional import cached_property
+
+
+class AttributeSetter:
+    def __init__(self, name, value):
+        setattr(self, name, value)
+
+
+class CompositeAttribute:
+    def __init__(self, field):
+        self.field = field
+
+    @property
+    def attnames(self):
+        return [field.attname for field in self.field.fields]
+
+    def __get__(self, instance, cls=None):
+        return tuple(getattr(instance, attname) for attname in self.attnames)
+
+    def __set__(self, instance, values):
+        attnames = self.attnames
+        length = len(attnames)
+
+        if values is None:
+            values = (None,) * length
+
+        if not isinstance(values, (list, tuple)):
+            raise ValueError(f"{self.field.name!r} must be a list or a tuple.")
+        if length != len(values):
+            raise ValueError(f"{self.field.name!r} must have {length} elements.")
+
+        for attname, value in zip(attnames, values):
+            setattr(instance, attname, value)
+
+
+class CompositePrimaryKey(Field):
+    descriptor_class = CompositeAttribute
+
+    def __init__(self, *args, **kwargs):
+        if (
+            not args
+            or not all(isinstance(field, str) for field in args)
+            or len(set(args)) != len(args)
+        ):
+            raise ValueError("CompositePrimaryKey args must be unique strings.")
+        if len(args) == 1:
+            raise ValueError("CompositePrimaryKey must include at least two fields.")
+        if kwargs.get("default", NOT_PROVIDED) is not NOT_PROVIDED:
+            raise ValueError("CompositePrimaryKey cannot have a default.")
+        if kwargs.get("db_default", NOT_PROVIDED) is not NOT_PROVIDED:
+            raise ValueError("CompositePrimaryKey cannot have a database default.")
+        if kwargs.get("db_column", None) is not None:
+            raise ValueError("CompositePrimaryKey cannot have a db_column.")
+        if kwargs.setdefault("editable", False):
+            raise ValueError("CompositePrimaryKey cannot be editable.")
+        if not kwargs.setdefault("primary_key", True):
+            raise ValueError("CompositePrimaryKey must be a primary key.")
+        if not kwargs.setdefault("blank", True):
+            raise ValueError("CompositePrimaryKey must be blank.")
+
+        self.field_names = args
+        super().__init__(**kwargs)
+
+    def deconstruct(self):
+        # args is always [] so it can be ignored.
+        name, path, _, kwargs = super().deconstruct()
+        return name, path, self.field_names, kwargs
+
+    @cached_property
+    def fields(self):
+        meta = self.model._meta
+        return tuple(meta.get_field(field_name) for field_name in self.field_names)
+
+    @cached_property
+    def columns(self):
+        return tuple(field.column for field in self.fields)
+
+    def contribute_to_class(self, cls, name, private_only=False):
+        super().contribute_to_class(cls, name, private_only=private_only)
+        cls._meta.pk = self
+        setattr(cls, self.attname, self.descriptor_class(self))
+
+    def get_attname_column(self):
+        return self.get_attname(), None
+
+    def __iter__(self):
+        return iter(self.fields)
+
+    def __len__(self):
+        return len(self.field_names)
+
+    @cached_property
+    def cached_col(self):
+        return ColPairs(self.model._meta.db_table, self.fields, self.fields, self)
+
+    def get_col(self, alias, output_field=None):
+        if alias == self.model._meta.db_table and (
+            output_field is None or output_field == self
+        ):
+            return self.cached_col
+
+        return ColPairs(alias, self.fields, self.fields, output_field)
+
+    def get_pk_value_on_save(self, instance):
+        values = []
+
+        for field in self.fields:
+            value = field.value_from_object(instance)
+            if value is None:
+                value = field.get_pk_value_on_save(instance)
+            values.append(value)
+
+        return tuple(values)
+
+    def _check_field_name(self):
+        if self.name == "pk":
+            return []
+        return [
+            checks.Error(
+                "'CompositePrimaryKey' must be named 'pk'.",
+                obj=self,
+                id="fields.E013",
+            )
+        ]
+
+    def value_to_string(self, obj):
+        values = []
+        vals = self.value_from_object(obj)
+        for field, value in zip(self.fields, vals):
+            obj = AttributeSetter(field.attname, value)
+            values.append(field.value_to_string(obj))
+        return json.dumps(values, ensure_ascii=False)
+
+    def to_python(self, value):
+        if isinstance(value, str):
+            # Assume we're deserializing.
+            vals = json.loads(value)
+            value = [
+                field.to_python(val)
+                for field, val in zip(self.fields, vals, strict=True)
+            ]
+        return value
+
+
+CompositePrimaryKey.register_lookup(TupleExact)
+CompositePrimaryKey.register_lookup(TupleGreaterThan)
+CompositePrimaryKey.register_lookup(TupleGreaterThanOrEqual)
+CompositePrimaryKey.register_lookup(TupleLessThan)
+CompositePrimaryKey.register_lookup(TupleLessThanOrEqual)
+CompositePrimaryKey.register_lookup(TupleIn)
+CompositePrimaryKey.register_lookup(TupleIsNull)
+
+
+def unnest(fields):
+    result = []
+
+    for field in fields:
+        if isinstance(field, CompositePrimaryKey):
+            result.extend(field.fields)
+        else:
+            result.append(field)
+
+    return result