python lsp

server/libs/cattrs/preconf/tomlkit.py

@@ -0,0 +1,89 @@
+"""Preconfigured converters for tomlkit."""
+
+from base64 import b85decode, b85encode
+from collections.abc import Set
+from datetime import date, datetime
+from enum import Enum
+from operator import attrgetter
+from typing import Any, TypeVar, Union
+
+from tomlkit import dumps, loads
+from tomlkit.items import Float, Integer, String
+
+from .._compat import is_mapping, is_subclass
+from ..converters import BaseConverter, Converter
+from ..strategies import configure_union_passthrough
+from . import validate_datetime, wrap
+
+__all__ = ["TomlkitConverter", "configure_converter", "make_converter"]
+
+T = TypeVar("T")
+_enum_value_getter = attrgetter("_value_")
+
+
+class TomlkitConverter(Converter):
+    def dumps(self, obj: Any, unstructure_as: Any = None, **kwargs: Any) -> str:
+        return dumps(self.unstructure(obj, unstructure_as=unstructure_as), **kwargs)
+
+    def loads(self, data: str, cl: type[T]) -> T:
+        return self.structure(loads(data), cl)
+
+
+def configure_converter(converter: BaseConverter):
+    """
+    Configure the converter for use with the tomlkit library.
+
+    * bytes are serialized as base85 strings
+    * sets are serialized as lists
+    * tuples are serializas as lists
+    * mapping keys are coerced into strings when unstructuring
+    """
+    converter.register_structure_hook(bytes, lambda v, _: b85decode(v))
+    converter.register_unstructure_hook(
+        bytes, lambda v: (b85encode(v) if v else b"").decode("utf8")
+    )
+
+    def gen_unstructure_mapping(cl: Any, unstructure_to=None):
+        key_handler = str
+        args = getattr(cl, "__args__", None)
+        if args:
+            # Currently, tomlkit has inconsistent behavior on 3.11
+            # so we paper over it here.
+            # https://github.com/sdispater/tomlkit/issues/237
+            if is_subclass(args[0], str):
+                key_handler = _enum_value_getter if is_subclass(args[0], Enum) else None
+            elif is_subclass(args[0], bytes):
+
+                def key_handler(k: bytes):
+                    return b85encode(k).decode("utf8")
+
+        return converter.gen_unstructure_mapping(
+            cl, unstructure_to=unstructure_to, key_handler=key_handler
+        )
+
+    converter._unstructure_func.register_func_list(
+        [(is_mapping, gen_unstructure_mapping, True)]
+    )
+
+    # datetime inherits from date, so identity unstructure hook used
+    # here to prevent the date unstructure hook running.
+    converter.register_unstructure_hook(datetime, lambda v: v)
+    converter.register_structure_hook(datetime, validate_datetime)
+    converter.register_unstructure_hook(date, lambda v: v.isoformat())
+    converter.register_structure_hook(date, lambda v, _: date.fromisoformat(v))
+    configure_union_passthrough(
+        Union[str, String, bool, int, Integer, float, Float], converter
+    )
+
+
+@wrap(TomlkitConverter)
+def make_converter(*args: Any, **kwargs: Any) -> TomlkitConverter:
+    kwargs["unstruct_collection_overrides"] = {
+        Set: list,
+        tuple: list,
+        **kwargs.get("unstruct_collection_overrides", {}),
+    }
+    res = TomlkitConverter(*args, **kwargs)
+    configure_converter(res)
+
+    return res