bpo-46805: Add low level UDP socket functions to asyncio (GH-31455)

Lib/asyncio/selector_events.py

@@ -434,6 +434,88 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
         else:
             fut.set_result(nbytes)
 
+    async def sock_recvfrom(self, sock, bufsize):
+        """Receive a datagram from a datagram socket.
+
+        The return value is a tuple of (bytes, address) representing the
+        datagram received and the address it came from.
+        The maximum amount of data to be received at once is specified by
+        nbytes.
+        """
+        base_events._check_ssl_socket(sock)
+        if self._debug and sock.gettimeout() != 0:
+            raise ValueError("the socket must be non-blocking")
+        try:
+            return sock.recvfrom(bufsize)
+        except (BlockingIOError, InterruptedError):
+            pass
+        fut = self.create_future()
+        fd = sock.fileno()
+        self._ensure_fd_no_transport(fd)
+        handle = self._add_reader(fd, self._sock_recvfrom, fut, sock, bufsize)
+        fut.add_done_callback(
+            functools.partial(self._sock_read_done, fd, handle=handle))
+        return await fut
+
+    def _sock_recvfrom(self, fut, sock, bufsize):
+        # _sock_recvfrom() can add itself as an I/O callback if the operation
+        # can't be done immediately. Don't use it directly, call
+        # sock_recvfrom().
+        if fut.done():
+            return
+        try:
+            result = sock.recvfrom(bufsize)
+        except (BlockingIOError, InterruptedError):
+            return  # try again next time
+        except (SystemExit, KeyboardInterrupt):
+            raise
+        except BaseException as exc:
+            fut.set_exception(exc)
+        else:
+            fut.set_result(result)
+
+    async def sock_recvfrom_into(self, sock, buf, nbytes=0):
+        """Receive data from the socket.
+
+        The received data is written into *buf* (a writable buffer).
+        The return value is a tuple of (number of bytes written, address).
+        """
+        base_events._check_ssl_socket(sock)
+        if self._debug and sock.gettimeout() != 0:
+            raise ValueError("the socket must be non-blocking")
+        if not nbytes:
+            nbytes = len(buf)
+          
+        try:
+            return sock.recvfrom_into(buf, nbytes)
+        except (BlockingIOError, InterruptedError):
+            pass
+        fut = self.create_future()
+        fd = sock.fileno()
+        self._ensure_fd_no_transport(fd)
+        handle = self._add_reader(fd, self._sock_recvfrom_into, fut, sock, buf,
+                                  nbytes)
+        fut.add_done_callback(
+            functools.partial(self._sock_read_done, fd, handle=handle))
+        return await fut
+
+    def _sock_recvfrom_into(self, fut, sock, buf, bufsize):
+        # _sock_recv_into() can add itself as an I/O callback if the operation
+        # can't be done immediately. Don't use it directly, call
+        # sock_recv_into().
+        if fut.done():
+            return
+        try:
+            result = sock.recvfrom_into(buf, bufsize)
+        except (BlockingIOError, InterruptedError):
+            return  # try again next time
+        except (SystemExit, KeyboardInterrupt):
+            raise
+        except BaseException as exc:
+            fut.set_exception(exc)
+        else:
+            fut.set_result(result)
+
     async def sock_sendall(self, sock, data):
         """Send data to the socket.
 
@@ -487,6 +569,48 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
         else:
             pos[0] = start
 
+    async def sock_sendto(self, sock, data, address):
+        """Send data to the socket.
+
+        The socket must be connected to a remote socket. This method continues
+        to send data from data until either all data has been sent or an
+        error occurs. None is returned on success. On error, an exception is
+        raised, and there is no way to determine how much data, if any, was
+        successfully processed by the receiving end of the connection.
+        """
+        base_events._check_ssl_socket(sock)
+        if self._debug and sock.gettimeout() != 0:
+            raise ValueError("the socket must be non-blocking")
+        try:
+            return sock.sendto(data, address)
+        except (BlockingIOError, InterruptedError):
+            pass
+
+        fut = self.create_future()
+        fd = sock.fileno()
+        self._ensure_fd_no_transport(fd)
+        # use a trick with a list in closure to store a mutable state
+        handle = self._add_writer(fd, self._sock_sendto, fut, sock, data,
+                                  address)
+        fut.add_done_callback(
+            functools.partial(self._sock_write_done, fd, handle=handle))
+        return await fut
+
+    def _sock_sendto(self, fut, sock, data, address):
+        if fut.done():
+            # Future cancellation can be scheduled on previous loop iteration
+            return
+        try:
+            n = sock.sendto(data, 0, address)
+        except (BlockingIOError, InterruptedError):
+            return
+        except (SystemExit, KeyboardInterrupt):
+            raise
+        except BaseException as exc:
+            fut.set_exception(exc)
+        else:
+            fut.set_result(n)
+
     async def sock_connect(self, sock, address):
         """Connect to a remote socket at address.