def hash_tree_root(value: Any, sedes: BaseSedes=None) -> Hash32:
if sedes is None:
sedes = infer_sedes(value)
intermediate_tree_hash = sedes.intermediate_tree_hash(value)
if len(intermediate_tree_hash) < 32:
return Hash32(intermediate_tree_hash.ljust(32, b'\x00'))
else:
return Hash32(intermediate_tree_hash)
def get_hash_tree_root(value: Any, sedes: BaseSedes = None) -> Hash32:
if sedes is None:
sedes = infer_sedes(value)
return sedes.get_hash_tree_root(value)
if cls._meta.field_names[-1] != SIGNATURE_FIELD_NAME:
raise TypeError(
f"Last field of signed serializable must be {SIGNATURE_FIELD_NAME}, but is "
f"{cls._meta.field_names[-1]}")
signed_container_sedes = Container(
cls._meta.container_sedes.field_sedes[:-1])
else:
signed_container_sedes = None
meta = SignedMeta(
has_fields=cls._meta.has_fields,
fields=cls._meta.fields,
container_sedes=cls._meta.container_sedes,
signed_container_sedes=signed_container_sedes,
field_names=cls._meta.field_names,
field_attrs=cls._meta.field_attrs,
)
cls._meta = meta
return cls
BaseSedes.register(MetaSignedSerializable)
class SignedSerializable(BaseSerializable, metaclass=MetaSignedSerializable):
@property
def signing_root(self):
return ssz.get_hash_tree_root(self, self._meta.signed_container_sedes)
deserialized_field_dict = cls._meta.container_sedes.deserialize(data)
return cls(**deserialized_field_dict)
def deserialize_segment(cls: Type[TSerializable], data: bytes,
start_index: int) -> Tuple[TSerializable, int]:
deserialized_field_dict, continuation_index = cls._meta.container_sedes.deserialize_segment(
data,
start_index,
)
return cls(**deserialized_field_dict), continuation_index
def consume_bytes(cls, data: bytes, start_index: int,
num_bytes: int) -> Tuple[bytes, int]:
return cls._meta.container_sedes.consume_bytes(data, start_index,
num_bytes)
def intermediate_tree_hash(cls: Type[TSerializable],
value: TSerializable) -> bytes:
return cls._meta.container_sedes.intermediate_tree_hash(value)
# Make any class created with SerializableBase an instance of BaseSedes
BaseSedes.register(SerializableBase)
class Serializable(BaseSerializable, metaclass=SerializableBase):
"""
The base class for serializable objects.
"""
pass
cls = super().__new__(mcls, name, bases, namespace)
# check that the signature conventions are abided by
if cls._meta is not None:
if len(cls._meta.fields) < 2:
raise TypeError(f"Signed containers need to have at least two fields")
if cls._meta.fields[-1][0] != SIGNATURE_FIELD_NAME:
raise TypeError(
f"Last field of signed container must be {SIGNATURE_FIELD_NAME}, but is "
f"{cls._meta.fields[-1][0]}"
)
return cls
BaseSedes.register(MetaHashableContainer)
BaseSedes.register(MetaSignedHashableContainer)
# workaround for https://github.com/python/typing/issues/449 (fixed in python 3.7)
python_version_info = sys.version_info
if python_version_info[0] <= 3 and python_version_info[1] <= 6:
from typing import GenericMeta
class GenericMetaHashableContainer(GenericMeta, MetaHashableContainer):
pass
class GenericMetaSignedHashableContainer(
GenericMetaHashableContainer, MetaSignedHashableContainer
):
pass