circuitpython/extmod/uasyncio/stream.py
Miguel Grinberg de2e081260 extmod/uasyncio: Fix start_server and wait_closed race condition.
This fix prevents server.wait_closed() from raising an AttributeError when
trying to access server.task.  This can happen if it is called immediately
after start_server().
2021-06-08 15:10:50 +10:00

158 lines
4.1 KiB
Python

# MicroPython uasyncio module
# MIT license; Copyright (c) 2019-2020 Damien P. George
from . import core
class Stream:
def __init__(self, s, e={}):
self.s = s
self.e = e
self.out_buf = b""
def get_extra_info(self, v):
return self.e[v]
async def __aenter__(self):
return self
async def __aexit__(self, exc_type, exc, tb):
await self.close()
def close(self):
pass
async def wait_closed(self):
# TODO yield?
self.s.close()
async def read(self, n):
yield core._io_queue.queue_read(self.s)
return self.s.read(n)
async def readexactly(self, n):
r = b""
while n:
yield core._io_queue.queue_read(self.s)
r2 = self.s.read(n)
if r2 is not None:
if not len(r2):
raise EOFError
r += r2
n -= len(r2)
return r
async def readline(self):
l = b""
while True:
yield core._io_queue.queue_read(self.s)
l2 = self.s.readline() # may do multiple reads but won't block
l += l2
if not l2 or l[-1] == 10: # \n (check l in case l2 is str)
return l
def write(self, buf):
self.out_buf += buf
async def drain(self):
mv = memoryview(self.out_buf)
off = 0
while off < len(mv):
yield core._io_queue.queue_write(self.s)
ret = self.s.write(mv[off:])
if ret is not None:
off += ret
self.out_buf = b""
# Stream can be used for both reading and writing to save code size
StreamReader = Stream
StreamWriter = Stream
# Create a TCP stream connection to a remote host
async def open_connection(host, port):
from uerrno import EINPROGRESS
import usocket as socket
ai = socket.getaddrinfo(host, port)[0] # TODO this is blocking!
s = socket.socket()
s.setblocking(False)
ss = Stream(s)
try:
s.connect(ai[-1])
except OSError as er:
if er.errno != EINPROGRESS:
raise er
yield core._io_queue.queue_write(s)
return ss, ss
# Class representing a TCP stream server, can be closed and used in "async with"
class Server:
async def __aenter__(self):
return self
async def __aexit__(self, exc_type, exc, tb):
self.close()
await self.wait_closed()
def close(self):
self.task.cancel()
async def wait_closed(self):
await self.task
async def _serve(self, cb, host, port, backlog):
import usocket as socket
ai = socket.getaddrinfo(host, port)[0] # TODO this is blocking!
s = socket.socket()
s.setblocking(False)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(ai[-1])
s.listen(backlog)
# Accept incoming connections
while True:
try:
yield core._io_queue.queue_read(s)
except core.CancelledError:
# Shutdown server
s.close()
return
try:
s2, addr = s.accept()
except:
# Ignore a failed accept
continue
s2.setblocking(False)
s2s = Stream(s2, {"peername": addr})
core.create_task(cb(s2s, s2s))
# Helper function to start a TCP stream server, running as a new task
# TODO could use an accept-callback on socket read activity instead of creating a task
async def start_server(cb, host, port, backlog=5):
s = Server()
s.task = core.create_task(s._serve(cb, host, port, backlog))
return s
################################################################################
# Legacy uasyncio compatibility
async def stream_awrite(self, buf, off=0, sz=-1):
if off != 0 or sz != -1:
buf = memoryview(buf)
if sz == -1:
sz = len(buf)
buf = buf[off : off + sz]
self.write(buf)
await self.drain()
Stream.aclose = Stream.wait_closed
Stream.awrite = stream_awrite
Stream.awritestr = stream_awrite # TODO explicitly convert to bytes?