[_cffi_backend] Improve CField, CType, _CDataBase, buffer

Author: mildsunrise

stubs/cffi/_cffi_backend.pyi

@@ -2,7 +2,7 @@ import sys
 import types
 from _typeshed import Incomplete, ReadableBuffer, WriteableBuffer
 from collections.abc import Callable, Hashable
-from typing import Any, ClassVar, Literal, Protocol, SupportsIndex, TypeVar, final, overload, type_check_only
+from typing import Any, ClassVar, Literal, Optional, Protocol, Self, SupportsIndex, TypeVar, final, overload, type_check_only
 from typing_extensions import Self, TypeAlias, disjoint_base
 
 _T = TypeVar("_T")
@@ -27,11 +27,11 @@ if sys.platform != "win32":
 
 @final
 class CField:
-    bitshift: Incomplete
-    bitsize: Incomplete
-    flags: Incomplete
-    offset: Incomplete
-    type: Incomplete
+	bitshift: int
+	bitsize: int
+	flags: int
+	offset: int
+	type: 'CType'
 
 @final
 class CLibrary:
@@ -42,18 +42,21 @@ class CLibrary:
 
 @final
 class CType:
-    abi: Incomplete
-    args: Incomplete
-    cname: Incomplete
-    elements: Incomplete
-    ellipsis: Incomplete
-    fields: Incomplete
-    item: Incomplete
-    kind: Incomplete
-    length: Incomplete
-    relements: Incomplete
-    result: Incomplete
-    def __dir__(self): ...
+    cname: str
+    kind: Literal['enum', 'primitive', 'pointer', 'array', 'void', 'struct', 'union', 'function']
+
+	abi: int
+	args: tuple['CType', ...]
+	ellipsis: bool
+	result: 'CType'
+
+    item: 'CType'
+    length: Optional[int]
+
+	fields: Optional[list[tuple[str, CField]]]
+
+	relements: dict[str, int]
+	elements: dict[int, str]
 
 @final
 class Lib:
@@ -62,48 +65,52 @@ class Lib:
 @final
 class _CDataBase:
     __name__: ClassVar[str]
-    def __add__(self, other, /): ...
-    def __bool__(self) -> bool: ...
-    def __call__(self, *args, **kwargs): ...
-    def __complex__(self) -> complex: ...
-    def __delitem__(self, other, /) -> None: ...
     def __dir__(self): ...
-    def __enter__(self): ...
-    def __eq__(self, other, /): ...
+
+    def __enter__(self) -> Self: ...
     def __exit__(
         self, type: type[BaseException] | None, value: BaseException | None, traceback: types.TracebackType | None, /
     ): ...
+
+    def __add__(self, other, /): ...
+    def __sub__(self, other, /): ...
+    def __radd__(self, other, /): ...
+    def __rsub__(self, other, /): ...
+
+    def __call__(self, *args): ...
+
+    def __hash__(self) -> int: ...
+    def __bool__(self) -> bool: ...
+    def __int__(self) -> int: ...
     def __float__(self) -> float: ...
+    def __complex__(self) -> complex: ...
+
+    def __eq__(self, other, /): ...
+    def __ne__(self, other, /): ...
     def __ge__(self, other, /): ...
-    def __getitem__(self, index: SupportsIndex | slice, /): ...
     def __gt__(self, other, /): ...
-    def __hash__(self) -> int: ...
-    def __int__(self) -> int: ...
-    def __iter__(self): ...
     def __le__(self, other, /): ...
-    def __len__(self) -> int: ...
     def __lt__(self, other, /): ...
-    def __ne__(self, other, /): ...
-    def __radd__(self, other, /): ...
-    def __rsub__(self, other, /): ...
+
+    def __iter__(self): ...
+    def __len__(self) -> int: ...
+    def __getitem__(self, index: SupportsIndex | slice, /): ...
     def __setitem__(self, index: SupportsIndex | slice, object, /) -> None: ...
-    def __sub__(self, other, /): ...
 
 @final
 class buffer:
-    __hash__: ClassVar[None]  # type: ignore[assignment]
-    def __new__(cls, *args, **kwargs) -> Self: ...
-    def __buffer__(self, flags: int, /) -> memoryview: ...
-    def __delitem__(self, other, /) -> None: ...
-    def __eq__(self, other, /): ...
-    def __ge__(self, other, /): ...
-    def __getitem__(self, index, /): ...
-    def __gt__(self, other, /): ...
-    def __le__(self, other, /): ...
-    def __len__(self) -> int: ...
-    def __lt__(self, other, /): ...
-    def __ne__(self, other, /): ...
-    def __setitem__(self, index, object, /) -> None: ...
+	__hash__: ClassVar[None]  # type: ignore[assignment]
+	def __new__(cls, cdata: _CDataBase, size: int = -1) -> Self: ...
+	def __buffer__(self, flags: int, /) -> memoryview: ...
+	def __eq__(self, other: ReadableBuffer, /) -> bool: ...
+	def __ne__(self, other: ReadableBuffer, /) -> bool: ...
+	def __ge__(self, other: ReadableBuffer, /) -> bool: ...
+	def __gt__(self, other: ReadableBuffer, /) -> bool: ...
+	def __le__(self, other: ReadableBuffer, /) -> bool: ...
+	def __lt__(self, other: ReadableBuffer, /) -> bool: ...
+	def __len__(self) -> int: ...
+	def __getitem__(self, index: SupportsIndex | slice, /) -> bytes: ...
+	def __setitem__(self, index: SupportsIndex | slice, value: bytes, /) -> None: ...
 
 # These aliases are to work around pyright complaints.
 # Pyright doesn't like it when a class object is defined as an alias