pub/python-betterproto
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Store the class metadata of fields in the class, to improve preformance

Browse Source 
Cached data include,
- lookup table between groups and fields of "oneof" fields
- default value creator of each field
- type hint of each field
This commit is contained in:
James Lan
2020-05-14 15:20:23 -07:00
parent de61ddab21
commit 3d001a2a1a
3 changed files with 117 additions and 64 deletions
Download Patch File Download Diff File Expand all files Collapse all files

148
betterproto/__init__.py
View File

@@ -120,7 +120,11 @@ WIRE_LEN_DELIM_TYPES = [TYPE_STRING, TYPE_BYTES, TYPE_MESSAGE, TYPE_MAP]
# Protobuf datetimes start at the Unix Epoch in 1970 in UTC.
DATETIME_ZERO = datetime(1970, 1, 1, tzinfo=timezone.utc)
def datetime_default_gen():
return datetime(1970, 1, 1, tzinfo=timezone.utc)
DATETIME_ZERO = datetime_default_gen()
class Casing(enum.Enum):
@@ -428,6 +432,57 @@ def parse_fields(value: bytes) -> Generator[ParsedField, None, None]:
T = TypeVar("T", bound="Message")
class ProtoClassMetadata:
cls: "Message"
def __init__(self, cls: "Message"):
self.cls = cls
by_field = {}
by_group = {}
for field in dataclasses.fields(cls):
meta = FieldMetadata.get(field)
if meta.group:
# This is part of a one-of group.
by_field[field.name] = meta.group
by_group.setdefault(meta.group, set()).add(field)
self.oneof_group_by_field = by_field
self.oneof_field_by_group = by_group
def __getattr__(self, item):
# Lazy init because forward reference classes may not be available at the beginning.
if item == 'default_gen':
defaults = {}
for field in dataclasses.fields(self.cls):
meta = FieldMetadata.get(field)
defaults[field.name] = self.cls._get_field_default_gen(field, meta)
self.default_gen = defaults # __getattr__ won't be called next time
return defaults
if item == 'cls_by_field':
field_cls = {}
for field in dataclasses.fields(self.cls):
meta = FieldMetadata.get(field)
field_cls[field.name] = self.cls._type_hint(field.name)
self.cls_by_field = field_cls # __getattr__ won't be called next time
return field_cls
def make_protoclass(cls):
setattr(cls, "_betterproto", ProtoClassMetadata(cls))
def protoclass(*args, **kwargs):
cls = dataclasses.dataclass(*args, **kwargs)
make_protoclass(cls)
return cls
class Message(ABC):
"""
A protobuf message base class. Generated code will inherit from this and
@@ -445,17 +500,12 @@ class Message(ABC):
# Set a default value for each field in the class after `__init__` has
# already been run.
group_map: Dict[str, dict] = {"fields": {}, "groups": {}}
group_map: Dict[str, dataclasses.Field] = {}
for field in dataclasses.fields(self):
meta = FieldMetadata.get(field)
if meta.group:
# This is part of a one-of group.
group_map["fields"][field.name] = meta.group
if meta.group not in group_map["groups"]:
group_map["groups"][meta.group] = {"current": None, "fields": set()}
group_map["groups"][meta.group]["fields"].add(field)
group_map.setdefault(meta.group)
if getattr(self, field.name) != PLACEHOLDER:
# Skip anything not set to the sentinel value
@@ -463,7 +513,7 @@ class Message(ABC):
if meta.group:
# This was set, so make it the selected value of the one-of.
group_map["groups"][meta.group]["current"] = field
group_map[meta.group] = field
continue
@@ -479,16 +529,17 @@ class Message(ABC):
# Track when a field has been set.
self.__dict__["_serialized_on_wire"] = True
if attr in getattr(self, "_group_map", {}).get("fields", {}):
group = self._group_map["fields"][attr]
for field in self._group_map["groups"][group]["fields"]:
if field.name == attr:
self._group_map["groups"][group]["current"] = field
else:
super().__setattr__(
field.name,
self._get_field_default(field, FieldMetadata.get(field)),
)
if hasattr(self, "_group_map"): # __post_init__ had already run
if attr in self._betterproto.oneof_group_by_field:
group = self._betterproto.oneof_group_by_field[attr]
for field in self._betterproto.oneof_field_by_group[group]:
if field.name == attr:
self._group_map[group] = field
else:
super().__setattr__(
field.name,
self._get_field_default(field, FieldMetadata.get(field)),
)
super().__setattr__(attr, value)
@@ -510,7 +561,7 @@ class Message(ABC):
# currently set in a `oneof` group, so it must be serialized even
# if the value is the default zero value.
selected_in_group = False
if meta.group and self._group_map["groups"][meta.group]["current"] == field:
if meta.group and self._group_map[meta.group] == field:
selected_in_group = True
serialize_empty = False
@@ -562,47 +613,49 @@ class Message(ABC):
# For compatibility with other libraries
SerializeToString = __bytes__
def _type_hint(self, field_name: str) -> Type:
module = inspect.getmodule(self.__class__)
type_hints = get_type_hints(self.__class__, vars(module))
@classmethod
def _type_hint(cls, field_name: str) -> Type:
module = inspect.getmodule(cls)
type_hints = get_type_hints(cls, vars(module))
return type_hints[field_name]
def _cls_for(self, field: dataclasses.Field, index: int = 0) -> Type:
"""Get the message class for a field from the type hints."""
cls = self._type_hint(field.name)
cls = self._betterproto.cls_by_field[field.name]
if hasattr(cls, "__args__") and index >= 0:
cls = cls.__args__[index]
return cls
def _get_field_default(self, field: dataclasses.Field, meta: FieldMetadata) -> Any:
t = self._type_hint(field.name)
return self._betterproto.default_gen[field.name]()
@classmethod
def _get_field_default_gen(cls, field: dataclasses.Field, meta: FieldMetadata) -> Any:
t = cls._type_hint(field.name)
value: Any = 0
if hasattr(t, "__origin__"):
if t.__origin__ in (dict, Dict):
# This is some kind of map (dict in Python).
value = {}
return dict
elif t.__origin__ in (list, List):
# This is some kind of list (repeated) field.
value = []
return list
elif t.__origin__ == Union and t.__args__[1] == type(None):
# This is an optional (wrapped) field. For setting the default we
# really don't care what kind of field it is.
value = None
return type(None)
else:
value = t()
return t
elif issubclass(t, Enum):
# Enums always default to zero.
value = 0
return int
elif t == datetime:
# Offsets are relative to 1970-01-01T00:00:00Z
value = DATETIME_ZERO
return datetime_default_gen
else:
# This is either a primitive scalar or another message type. Calling
# it should result in its zero value.
value = t()
return value
return t
def _postprocess_single(
self, wire_type: int, meta: FieldMetadata, field: dataclasses.Field, value: Any
@@ -654,6 +707,7 @@ class Message(ABC):
],
bases=(Message,),
)
make_protoclass(Entry)
value = Entry().parse(value)
return value
@@ -861,13 +915,13 @@ def serialized_on_wire(message: Message) -> bool:
def which_one_of(message: Message, group_name: str) -> Tuple[str, Any]:
"""Return the name and value of a message's one-of field group."""
field = message._group_map["groups"].get(group_name, {}).get("current")
field = message._group_map.get(group_name)
if not field:
return ("", None)
return (field.name, getattr(message, field.name))
@dataclasses.dataclass
@protoclass
class _Duration(Message):
# Signed seconds of the span of time. Must be from -315,576,000,000 to
# +315,576,000,000 inclusive. Note: these bounds are computed from: 60
@@ -892,7 +946,7 @@ class _Duration(Message):
return ".".join(parts) + "s"
@dataclasses.dataclass
@protoclass
class _Timestamp(Message):
# Represents seconds of UTC time since Unix epoch 1970-01-01T00:00:00Z. Must
# be from 0001-01-01T00:00:00Z to 9999-12-31T23:59:59Z inclusive.
@@ -942,47 +996,47 @@ class _WrappedMessage(Message):
return self
@dataclasses.dataclass
@protoclass
class _BoolValue(_WrappedMessage):
value: bool = bool_field(1)
@dataclasses.dataclass
@protoclass
class _Int32Value(_WrappedMessage):
value: int = int32_field(1)
@dataclasses.dataclass
@protoclass
class _UInt32Value(_WrappedMessage):
value: int = uint32_field(1)
@dataclasses.dataclass
@protoclass
class _Int64Value(_WrappedMessage):
value: int = int64_field(1)
@dataclasses.dataclass
@protoclass
class _UInt64Value(_WrappedMessage):
value: int = uint64_field(1)
@dataclasses.dataclass
@protoclass
class _FloatValue(_WrappedMessage):
value: float = float_field(1)
@dataclasses.dataclass
@protoclass
class _DoubleValue(_WrappedMessage):
value: float = double_field(1)
@dataclasses.dataclass
@protoclass
class _StringValue(_WrappedMessage):
value: str = string_field(1)
@dataclasses.dataclass
@protoclass
class _BytesValue(_WrappedMessage):
value: bytes = bytes_field(1)