1 files changed, 99 insertions, 0 deletions
diff --git a/rest_framework/utils/serializer_helpers.py b/rest_framework/utils/serializer_helpers.py
new file mode 100644
index 00000000..a861ca07
--- /dev/null
+++ b/rest_framework/utils/serializer_helpers.py
@@ -0,0 +1,99 @@
+from rest_framework.compat import OrderedDict
+
+
+class ReturnDict(OrderedDict):
+    """
+    Return object from `serialier.data` for the `Serializer` class.
+    Includes a backlink to the serializer instance for renderers
+    to use if they need richer field information.
+    """
+    def __init__(self, *args, **kwargs):
+        self.serializer = kwargs.pop('serializer')
+        super(ReturnDict, self).__init__(*args, **kwargs)
+
+
+class ReturnList(list):
+    """
+    Return object from `serialier.data` for the `SerializerList` class.
+    Includes a backlink to the serializer instance for renderers
+    to use if they need richer field information.
+    """
+    def __init__(self, *args, **kwargs):
+        self.serializer = kwargs.pop('serializer')
+        super(ReturnList, self).__init__(*args, **kwargs)
+
+
+class BoundField(object):
+    """
+    A field object that also includes `.value` and `.error` properties.
+    Returned when iterating over a serializer instance,
+    providing an API similar to Django forms and form fields.
+    """
+    def __init__(self, field, value, errors, prefix=''):
+        self._field = field
+        self.value = value
+        self.errors = errors
+        self.name = prefix + self.field_name
+
+    def __getattr__(self, attr_name):
+        return getattr(self._field, attr_name)
+
+    @property
+    def _proxy_class(self):
+        return self._field.__class__
+
+    def __repr__(self):
+        return '<%s value=%s errors=%s>' % (
+            self.__class__.__name__, self.value, self.errors
+        )
+
+
+class NestedBoundField(BoundField):
+    """
+    This `BoundField` additionally implements __iter__ and __getitem__
+    in order to support nested bound fields. This class is the type of
+    `BoundField` that is used for serializer fields.
+    """
+    def __iter__(self):
+        for field in self.fields.values():
+            yield self[field.field_name]
+
+    def __getitem__(self, key):
+        field = self.fields[key]
+        value = self.value.get(key) if self.value else None
+        error = self.errors.get(key) if self.errors else None
+        if hasattr(field, 'fields'):
+            return NestedBoundField(field, value, error, prefix=self.name + '.')
+        return BoundField(field, value, error, prefix=self.name + '.')
+
+
+class BindingDict(object):
+    """
+    This dict-like object is used to store fields on a serializer.
+
+    This ensures that whenever fields are added to the serializer we call
+    `field.bind()` so that the `field_name` and `parent` attributes
+    can be set correctly.
+    """
+    def __init__(self, serializer):
+        self.serializer = serializer
+        self.fields = OrderedDict()
+
+    def __setitem__(self, key, field):
+        self.fields[key] = field
+        field.bind(field_name=key, parent=self.serializer)
+
+    def __getitem__(self, key):
+        return self.fields[key]
+
+    def __delitem__(self, key):
+        del self.fields[key]
+
+    def items(self):
+        return self.fields.items()
+
+    def keys(self):
+        return self.fields.keys()
+
+    def values(self):
+        return self.fields.values()