Generate deserializers for requests

client/src/telethon/_impl/tl/core/__init__.py

@@ -1,5 +1,24 @@
-from .reader import Reader
+from .reader import (
+    Reader,
+    deserialize_bool,
+    deserialize_i32_list,
+    deserialize_i64_list,
+    deserialize_identity,
+    list_deserializer,
+    single_deserializer,
+)
 from .request import Request
 from .serializable import Serializable, serialize_bytes_to
 
-__all__ = ["Reader", "Request", "Serializable", "serialize_bytes_to"]
+__all__ = [
+    "Reader",
+    "deserialize_bool",
+    "deserialize_i32_list",
+    "deserialize_i64_list",
+    "deserialize_identity",
+    "list_deserializer",
+    "single_deserializer",
+    "Request",
+    "Serializable",
+    "serialize_bytes_to",
+]

client/src/telethon/_impl/tl/core/reader.py

@@ -1,5 +1,6 @@
+import functools
 import struct
-from typing import TYPE_CHECKING, Any, Optional, Type, TypeVar
+from typing import TYPE_CHECKING, Any, Callable, List, Optional, Type, TypeVar
 
 if TYPE_CHECKING:
     from .serializable import Serializable
@@ -85,3 +86,47 @@ class Reader:
             raise ValueError(f"No type found for constructor ID: {cid:x}")
         assert issubclass(ty, cls)
         return ty._read_from(self)
+
+
+@functools.cache
+def single_deserializer(cls: Type[T]) -> Callable[[bytes], T]:
+    def deserializer(body: bytes) -> T:
+        return Reader(body).read_serializable(cls)
+
+    return deserializer
+
+
+@functools.cache
+def list_deserializer(cls: Type[T]) -> Callable[[bytes], List[T]]:
+    def deserializer(body: bytes) -> List[T]:
+        reader = Reader(body)
+        vec_id, length = reader.read_fmt("<ii", 8)
+        assert vec_id == 0x1CB5C415 and length >= 0
+        return [reader.read_serializable(cls) for _ in range(length)]
+
+    return deserializer
+
+
+def deserialize_i64_list(body: bytes) -> List[int]:
+    reader = Reader(body)
+    vec_id, length = reader.read_fmt("<ii", 8)
+    assert vec_id == 0x1CB5C415 and length >= 0
+    return [*reader.read_fmt(f"<{length}q", length * 8)]
+
+
+def deserialize_i32_list(body: bytes) -> List[int]:
+    reader = Reader(body)
+    vec_id, length = reader.read_fmt("<ii", 8)
+    assert vec_id == 0x1CB5C415 and length >= 0
+    return [*reader.read_fmt(f"<{length}i", length * 4)]
+
+
+def deserialize_identity(body: bytes) -> bytes:
+    return body
+
+
+def deserialize_bool(body: bytes) -> bool:
+    reader = Reader(body)
+    bool_id = reader.read_fmt("<I", 4)[0]
+    assert isinstance(bool_id, int) and bool_id in (0x997275B5, 0xBC799737)
+    return bool_id == 0x997275B5

client/src/telethon/_impl/tl/core/request.py

@@ -1,9 +1,28 @@
 import struct
-from typing import Generic, TypeVar
+from typing import Any, Callable, Generic, Optional, TypeVar
 
 Return = TypeVar("Return")
 
 
+def _bootstrap_get_deserializer(
+    constructor_id: int,
+) -> Optional[Callable[[bytes], Any]]:
+    # Similar to Reader's bootstrapping.
+    if Request._get_deserializer is _bootstrap_get_deserializer:
+        from ..layer import RESPONSE_MAPPING as API_DESER
+        from ..mtproto.layer import RESPONSE_MAPPING as MTPROTO_DESER
+
+        if API_DESER.keys() & MTPROTO_DESER.keys():
+            raise RuntimeError(
+                "generated api and mtproto schemas cannot have colliding constructor identifiers"
+            )
+        ALL_DESER = API_DESER | MTPROTO_DESER
+
+        Request._get_deserializer = ALL_DESER.get  # type: ignore [assignment]
+
+    return Request._get_deserializer(constructor_id)
+
+
 class Request(bytes, Generic[Return]):
     __slots__ = ()
 
@@ -16,5 +35,12 @@ class Request(bytes, Generic[Return]):
         except struct.error:
             return 0
 
+    _get_deserializer = staticmethod(_bootstrap_get_deserializer)
+
+    def deserialize_response(self, response: bytes) -> Return:
+        deserializer = self._get_deserializer(self.constructor_id)
+        assert deserializer is not None
+        return deserializer(response)  # type: ignore [no-any-return]
+
     def debug_name(self) -> str:
         return f"request#{self.constructor_id:x}"

generator/src/telethon_generator/_impl/codegen/generator.py

@@ -11,7 +11,11 @@ from .serde.common import (
     to_class_name,
     to_method_name,
 )
-from .serde.deserialization import generate_read, param_value_fmt
+from .serde.deserialization import (
+    function_deserializer_fmt,
+    generate_read,
+    param_value_fmt,
+)
 from .serde.serialization import generate_function, generate_write
 
 
@@ -178,8 +182,10 @@ def generate(fs: FakeFs, tl: ParsedTl) -> None:
     )
 
     writer = fs.open(Path("layer.py"))
-    writer.write(f"from . import types")
-    writer.write(f"from .core import Serializable, Reader")
+    writer.write(f"from . import abcs, types")
+    writer.write(
+        f"from .core import Serializable, Reader, deserialize_bool, deserialize_i32_list, deserialize_i64_list, deserialize_identity, single_deserializer, list_deserializer"
+    )
     writer.write(f"from typing import cast, Tuple, Type")
     writer.write(f"LAYER = {tl.layer!r}")
     writer.write(
@@ -188,4 +194,10 @@ def generate(fs: FakeFs, tl: ParsedTl) -> None:
     for name in sorted(generated_type_names):
         writer.write(f"  types.{name},")
     writer.write("))}")
-    writer.write(f"__all__ = ['LAYER', 'TYPE_MAPPING']")
+    writer.write("RESPONSE_MAPPING = {")
+    for functiondef in tl.functiondefs:
+        writer.write(
+            f"  {hex(functiondef.id)}: {function_deserializer_fmt(functiondef)},"
+        )
+    writer.write("}")
+    writer.write(f"__all__ = ['LAYER', 'TYPE_MAPPING', 'RESPONSE_MAPPING']")

generator/src/telethon_generator/_impl/codegen/serde/deserialization.py

@@ -122,3 +122,43 @@ def param_value_fmt(param: Parameter) -> str:
         return f"_{param.name} == 0x997275b5"
     else:
         return f"_{param.name}"
+
+
+def function_deserializer_fmt(defn: Definition) -> str:
+    if defn.ty.generic_arg:
+        if defn.ty.name != ("Vector"):
+            raise NotImplementedError(
+                "generic_arg return for non-boxed-vectors not implemented"
+            )
+        elif defn.ty.generic_ref:
+            raise NotImplementedError(
+                "return for generic refs inside vector not implemented"
+            )
+        elif is_trivial(NormalParameter(ty=defn.ty.generic_arg, flag=None)):
+            if defn.ty.generic_arg.name == "int":
+                return "deserialize_i32_list"
+            elif defn.ty.generic_arg.name == "long":
+                return "deserialize_i64_list"
+            else:
+                raise NotImplementedError(
+                    f"return for trivial arg {defn.ty.generic_arg} not implemented"
+                )
+        elif defn.ty.generic_arg.bare:
+            raise NotImplementedError(
+                "return for non-boxed serializables inside a vector not implemented"
+            )
+        else:
+            return f"list_deserializer({inner_type_fmt(defn.ty.generic_arg)})"
+    elif defn.ty.generic_ref:
+        return "deserialize_identity"
+    elif is_trivial(NormalParameter(ty=defn.ty, flag=None)):
+        if defn.ty.name == "Bool":
+            return "deserialize_bool"
+        else:
+            raise NotImplementedError(
+                f"return for trivial arg {defn.ty} not implemented"
+            )
+    elif defn.ty.bare:
+        raise NotImplementedError("return for non-boxed serializables not implemented")
+    else:
+        return f"single_deserializer({inner_type_fmt(defn.ty)})"