tractor/tractor/trionics/_ordering.py

90 lines
1.9 KiB
Python

from __future__ import annotations
from heapq import (
heappush,
heappop
)
import trio
import msgspec
class OrderedPayload(msgspec.Struct, frozen=True):
index: int
payload: bytes
@classmethod
def from_msg(cls, msg: bytes) -> OrderedPayload:
return msgspec.msgpack.decode(msg, type=OrderedPayload)
def encode(self) -> bytes:
return msgspec.msgpack.encode(self)
def order_send_channel(
channel: trio.abc.SendChannel[bytes],
start_index: int = 0
):
next_index = start_index
send_lock = trio.StrictFIFOLock()
channel._send = channel.send
channel._aclose = channel.aclose
async def send(msg: bytes):
nonlocal next_index
async with send_lock:
await channel._send(
OrderedPayload(
index=next_index,
payload=msg
).encode()
)
next_index += 1
async def aclose():
async with send_lock:
await channel._aclose()
channel.send = send
channel.aclose = aclose
def order_receive_channel(
channel: trio.abc.ReceiveChannel[bytes],
start_index: int = 0
):
next_index = start_index
pqueue = []
channel._receive = channel.receive
def can_pop_next() -> bool:
return (
len(pqueue) > 0
and
pqueue[0][0] == next_index
)
async def drain_to_heap():
while not can_pop_next():
msg = await channel._receive()
msg = OrderedPayload.from_msg(msg)
heappush(pqueue, (msg.index, msg.payload))
def pop_next():
nonlocal next_index
_, msg = heappop(pqueue)
next_index += 1
return msg
async def receive() -> bytes:
if can_pop_next():
return pop_next()
await drain_to_heap()
return pop_next()
channel.receive = receive