[WIP] Make serializer interface streaming

.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[**]
+charset = utf-8
+end_of_line = lf
+
+indent_size = 4
+indent_style = tab
+max_line_length = 100

.travis.yml

@@ -4,13 +4,14 @@ matrix:
   include:
   - python: 3.7
     env: TOXENV=py37
+  - python: 3.8
+    env: TOXENV=py38
   - python: 3.7
     env: TOXENV=styleck
   - python: 3.7
     env: TOXENV=typeck
 
 install:
   - pip install tox
-#  - pip install -r requirements.txt
 
 script: tox

datastore/__init__.py

@@ -15,7 +15,8 @@
 	"BinaryNullDatastore", "BinaryDictDatastore",
 	"ObjectNullDatastore", "ObjectDictDatastore",
 	"Query", "Cursor",
-	"SerializerAdapter",
+	"SerializerAdapter", "SerializingError",
+	"SerializeError", "ParseError",
 
 	"abc", "typing", "util"
 )
@@ -38,6 +39,9 @@
 
 # import core.serialize
 from .core.serialize import SerializerAdapter
+from .core.serialize import SerializingError
+from .core.serialize import SerializeError
+from .core.serialize import ParseError
 
 
 ### Exposed submodules ###

datastore/abc.py

@@ -1,3 +1,16 @@
+__all__ = (
+	"BinaryDatastore",
+	"ObjectDatastore",
+
+	"BinaryAdapter",
+	"ObjectAdapter",
+
+	"ReceiveChannel",
+	"ReceiveStream",
+
+	"Serializer",
+)
+
 from .core.binarystore import Datastore as BinaryDatastore
 from .core.objectstore import Datastore as ObjectDatastore
 

datastore/adapter/_support.py

@@ -2,15 +2,19 @@
 
 import datastore
 
+T_co = typing.TypeVar("T_co", covariant=True)
 
 #XXX: Maybe retry describing this cooperative multiple inheritance scheme if these are ever added:
 #
-#  * https://github.com/python/mypy/issues/7191 (Mixin classes in general)
 #  * https://github.com/python/mypy/issues/7790 (Associated types)
 #  * https://github.com/python/mypy/issues/7791 (Types of generic classes)
-DS = typing.TypeVar("DS", datastore.abc.BinaryDatastore, datastore.abc.ObjectDatastore)
-DA = typing.TypeVar("DA", datastore.abc.BinaryAdapter,   datastore.abc.ObjectAdapter)
-RT = typing.TypeVar("RT", datastore.abc.ReceiveStream,   datastore.abc.ReceiveChannel)
+DS = typing.TypeVar("DS", datastore.abc.BinaryDatastore,
+                    datastore.abc.ObjectDatastore[T_co])  # type: ignore[valid-type] # noqa: F821
+DA = typing.TypeVar("DA", datastore.abc.BinaryAdapter,
+                    datastore.abc.ObjectAdapter[T_co, T_co])  # type: ignore[valid-type] # noqa: F821, E501
+RT = typing.TypeVar("RT", datastore.abc.ReceiveStream,
+                    datastore.abc.ReceiveChannel[T_co])  # type: ignore[valid-type] # noqa: F821
+RV = typing.TypeVar("RV", bytes, typing.List[T_co])  # type: ignore[valid-type] # noqa: F821
 
 
 # Workaround for https://github.com/python/mypy/issues/708
@@ -29,6 +33,7 @@ def __set__(self, oself: typing.Any, value: T) -> None:
 
 class DatastoreCollectionMixin(typing.Generic[DS]):
 	"""Represents a collection of datastores."""
+	__slots__ = ()
 
 	_stores: typing.List[DS]
 

datastore/adapter/directory.py

@@ -2,8 +2,7 @@
 
 import datastore
 
-
-__all__ = ["ObjectDirectorySupport", "ObjectDatastore"]
+__all__ = ("ObjectDirectorySupport", "ObjectDatastore")
 
 
 T_co = typing.TypeVar("T_co", covariant=True)
@@ -153,6 +152,10 @@ class ObjectDatastore(
 		>>> rds.get(a)
 		[]
 	"""
+	__slots__ = ()
+
+	FORWARD_CONTAINS = True
+	FORWARD_GET_ALL  = True
 
 
 	async def _put(self, key: datastore.Key, value: datastore.abc.ReceiveChannel[T_co]) -> None:

datastore/adapter/keytransform.py

@@ -3,10 +3,9 @@
 import datastore
 
 from . import _support
-from ._support import DS, RT
+from ._support import DS, RT, RV, T_co
 
-
-__all__ = [
+__all__ = (
 	"BinaryAdapter",
 	"ObjectAdapter",
 
@@ -18,14 +17,14 @@
 
 	"BinaryNestedPathAdapter",
 	"ObjectNestedPathAdapter",
-]
+)
 
 
 
 KEY_TRANSFORM_T = typing.Callable[[datastore.Key], datastore.Key]
 
 
-class _Adapter(typing.Generic[DS]):
+class _Adapter(typing.Generic[DS, RT, RV]):
 	"""Represents a simple DatastoreAdapter that applies a transform on all incoming
 	   keys. For example:
 
@@ -46,59 +45,72 @@ class _Adapter(typing.Generic[DS]):
 		>>> ds.get(datastore.Key('/c/b/a'))
 		None
 	"""
+	__slots__ = ()
+
+	FORWARD_CONTAINS = True
+	FORWARD_GET_ALL  = True
 
 	key_transform_fn: _support.FunctionProperty[KEY_TRANSFORM_T]
 
 
-	@typing.no_type_check
 	def __init__(self, *args, key_transform: KEY_TRANSFORM_T = (lambda k: k), **kwargs):
 		"""Initializes KeyTransformDatastore with `keytransform` function."""
 		self.key_transform_fn = key_transform
-		super().__init__(*args, **kwargs)
+		super().__init__(*args, **kwargs)  # type: ignore[call-arg] # noqa: F821
 
 
-	@typing.no_type_check
 	async def get(self, key: datastore.Key) -> RT:
 		"""Return the object named by keytransform(key)."""
-		return await super().get(self.key_transform_fn(key))
+		return await super().get(self.key_transform_fn(key))  # type: ignore[misc] # noqa: F821
+
+
+	async def get_all(self, key: datastore.Key) -> RV:
+		"""Return the object named by keytransform(key)."""
+		return await super().get_all(self.key_transform_fn(key))  # type: ignore[misc] # noqa: F821
 
 
-	@typing.no_type_check
 	async def _put(self, key: datastore.Key, value: RT) -> None:
 		"""Stores the object names by keytransform(key)."""
-		await super()._put(self.key_transform_fn(key), value)
+		await super()._put(self.key_transform_fn(key), value)  # type: ignore[misc] # noqa: F821
 
 
-	@typing.no_type_check
 	async def delete(self, key: datastore.Key) -> None:
 		"""Removes the object named by keytransform(key)."""
-		await super().delete(self.key_transform_fn(key))
+		await super().delete(self.key_transform_fn(key))  # type: ignore[misc] # noqa: F821
 
 
-	@typing.no_type_check
 	async def contains(self, key: datastore.Key) -> bool:
 		"""Returns whether the object named by key is in this datastore."""
-		return await super().contains(self.key_transform_fn(key))
+		return await super().contains(self.key_transform_fn(key))  # type: ignore[misc] # noqa: F821
 
 
-	@typing.no_type_check
 	async def query(self, query: datastore.Query) -> datastore.Cursor:
 		"""Returns a sequence of objects matching criteria expressed in `query`"""
 		query = query.copy()
 		query.key = self.key_transform_fn(query.key)
-		return await super().query(query)
-
+		return await super().query(query)  # type: ignore[misc] # noqa: F821
 
-class BinaryAdapter(_Adapter[datastore.abc.BinaryDatastore], datastore.abc.BinaryAdapter):
-	...
 
+class BinaryAdapter(
+		_Adapter[datastore.abc.BinaryDatastore, datastore.abc.ReceiveStream, bytes],
+		datastore.abc.BinaryAdapter
+):
+	__slots__ = ("key_transform_fn",)
 
-class ObjectAdapter(_Adapter[datastore.abc.ObjectDatastore], datastore.abc.ObjectAdapter):
-	...
 
+class ObjectAdapter(
+		typing.Generic[T_co],
+		_Adapter[
+			datastore.abc.ObjectDatastore[T_co],
+			datastore.abc.ReceiveChannel[T_co],
+			typing.List[T_co]
+		],
+		datastore.abc.ObjectAdapter[T_co, T_co]
+):
+	__slots__ = ("key_transform_fn",)
 
 
-class _LowercaseKeyAdapter(_Adapter[DS], typing.Generic[DS]):
+class _LowercaseKeyAdapter(_Adapter[DS, RT, RV], typing.Generic[DS, RT, RV]):
 	"""Represents a simple DatastoreAdapter that lowercases all incoming keys.
 
 	For example:
@@ -121,6 +133,7 @@ class _LowercaseKeyAdapter(_Adapter[DS], typing.Generic[DS]):
 		>>> lds.get(datastore.Key('HeLlO'))
 		'world'
 	"""
+	__slots__ = ()
 
 	def __init__(self, *args, **kwargs):
 		"""Initializes KeyTransformDatastore with `key_transform` function."""
@@ -132,16 +145,27 @@ def lowercase_key(cls, key: datastore.Key) -> datastore.Key:
 		return datastore.Key(str(key).lower())
 
 
-class BinaryLowercaseKeyAdapter(_LowercaseKeyAdapter[datastore.abc.BinaryDatastore], datastore.abc.BinaryAdapter):  # noqa: E501
-	...
+class BinaryLowercaseKeyAdapter(
+		_LowercaseKeyAdapter[datastore.abc.BinaryDatastore, datastore.abc.ReceiveStream, bytes],
+		datastore.abc.BinaryAdapter
+):
+	__slots__ = ("key_transform_fn",)
 
 
-class ObjectLowercaseKeyAdapter(_LowercaseKeyAdapter[datastore.abc.ObjectDatastore], datastore.abc.ObjectAdapter):  # noqa: E501
-	...
+class ObjectLowercaseKeyAdapter(
+		typing.Generic[T_co],
+		_LowercaseKeyAdapter[
+			datastore.abc.ObjectDatastore[T_co],
+			datastore.abc.ReceiveChannel[T_co],
+			typing.List[T_co]
+		],
+		datastore.abc.ObjectAdapter[T_co, T_co]
+):
+	__slots__ = ("key_transform_fn",)
 
 
 
-class _NamespaceAdapter(_Adapter[DS], typing.Generic[DS]):
+class _NamespaceAdapter(_Adapter[DS, RT, RV], typing.Generic[DS, RT, RV]):
 	"""Represents a simple DatastoreAdapter that namespaces all incoming keys.
 	   For example:
 
@@ -163,6 +187,7 @@ class _NamespaceAdapter(_Adapter[DS], typing.Generic[DS]):
 		>>> ds.get(datastore.Key('/a/b/c/d'))
 		'cd'
 	"""
+	__slots__ = ()
 
 	namespace: datastore.Key
 
@@ -176,16 +201,27 @@ def namespace_key(self, key: datastore.Key) -> datastore.Key:
 		return self.namespace.child(key)
 
 
-class BinaryNamespaceAdapter(_NamespaceAdapter[datastore.abc.BinaryDatastore], datastore.abc.BinaryAdapter):  # noqa: E501
-	...
+class BinaryNamespaceAdapter(
+		_NamespaceAdapter[datastore.abc.BinaryDatastore, datastore.abc.ReceiveStream, bytes],
+		datastore.abc.BinaryAdapter
+):
+	__slots__ = ("key_transform_fn", "namespace",)
 
 
-class ObjectNamespaceAdapter(_NamespaceAdapter[datastore.abc.ObjectDatastore], datastore.abc.ObjectAdapter):  # noqa: E501
-	...
+class ObjectNamespaceAdapter(
+		typing.Generic[T_co],
+		_NamespaceAdapter[
+			datastore.abc.ObjectDatastore[T_co],
+			datastore.abc.ReceiveChannel[T_co],
+			typing.List[T_co]
+		],
+		datastore.abc.ObjectAdapter[T_co, T_co]
+):
+	__slots__ = ("key_transform_fn", "namespace",)
 
 
 
-class _NestedPathAdapter(_Adapter[DS], typing.Generic[DS]):
+class _NestedPathAdapter(_Adapter[DS, RT, RV], typing.Generic[DS, RT, RV]):
 	"""Represents a simple DatastoreAdapter that shards/namespaces incoming keys.
 
 	Incoming keys are sharded into nested namespaces. The idea is to use the key
@@ -210,6 +246,7 @@ class _NestedPathAdapter(_Adapter[DS], typing.Generic[DS]):
 		>>> ds.get(datastore.Key('/ab/ca/bc/abc'))
 		2
 	"""
+	__slots__ = ()
 
 	_default_depth:  int = 3
 	_default_length: int = 2
@@ -284,9 +321,20 @@ def nested_path(path: str, depth: int, length: int) -> str:
 		return '/'.join(components)
 
 
-class BinaryNestedPathAdapter(_NestedPathAdapter[datastore.abc.BinaryDatastore], datastore.abc.BinaryAdapter):  # noqa: E501
-	...
+class BinaryNestedPathAdapter(
+		_NestedPathAdapter[datastore.abc.BinaryDatastore, datastore.abc.ReceiveStream, bytes],
+		datastore.abc.BinaryAdapter
+):
+	__slots__ = ("key_transform_fn", "nest_depth", "nest_length", "nest_keyfn")
 
 
-class ObjectNestedPathAdapter(_NestedPathAdapter[datastore.abc.ObjectDatastore], datastore.abc.ObjectAdapter):  # noqa: E501
-	...
+class ObjectNestedPathAdapter(
+		typing.Generic[T_co],
+		_NestedPathAdapter[
+			datastore.abc.ObjectDatastore[T_co],
+			datastore.abc.ReceiveChannel[T_co],
+			typing.List[T_co]
+		],
+		datastore.abc.ObjectAdapter[T_co, T_co]
+):
+	__slots__ = ("key_transform_fn", "nest_depth", "nest_length", "nest_keyfn")