v6d3music/v6d3musicbase/event.py
2023-01-15 08:51:29 +00:00

61 lines
1.7 KiB
Python

__all__ = ('Event', 'SendableEvents', 'ReceivableEvents', 'Events', 'Receiver')
import asyncio
from typing import Callable, Generic, TypeVar
from typing_extensions import Self
from .responsetype import ResponseType
class Event:
def json(self) -> ResponseType:
raise NotImplementedError
T = TypeVar('T', bound=Event)
T_co = TypeVar('T_co', bound=Event, covariant=True)
T_contra = TypeVar('T_contra', bound=Event, contravariant=True)
class Receiver(Generic[T_contra]):
def __init__(self, receive: Callable[[T_contra], None], receivers: set[Self], /) -> None:
self.__receive = receive
self.__receivers = receivers
self.__receiving = False
def __enter__(self) -> None:
self.__receivers.add(self)
self.__receiving = True
def __exit__(self, exc_type, exc_val, exc_tb):
self.__receiving = False
self.__receivers.remove(self)
def receive(self, event: T_contra, /) -> None:
if self.__receiving:
self.__receive(event)
class SendableEvents(Generic[T_contra]):
def send(self, event: T_contra, /) -> None:
raise NotImplementedError
class ReceivableEvents(Generic[T_co]):
def receive(self, receive: Callable[[T_co], None], /) -> Receiver[T_co]:
raise NotImplementedError
class Events(Generic[T], SendableEvents[T], ReceivableEvents[T]):
def __init__(self) -> None:
self.__receivers: set[Receiver[T]] = set()
self.__loop = asyncio.get_running_loop()
def send(self, event: T, /) -> None:
for receiver in self.__receivers:
self.__loop.call_soon(receiver.receive, event)
def receive(self, receive: Callable[[T], None], /) -> Receiver[T]:
return Receiver(receive, self.__receivers)