Use asyncio.open_connection in the TcpClient

(cherry picked from commit 573fed1f512831cd9790130cc878655fef2fde98)

telethon/extensions/tcpclient.py

@@ -12,7 +12,6 @@ import errno
 import logging
 import socket
 import ssl
-from io import BytesIO
 
 CONN_RESET_ERRNOS = {
     errno.EBADF, errno.ENOTSOCK, errno.ENETUNREACH,
@@ -52,6 +51,8 @@ class TcpClient:
         self.proxy = proxy
         self.ssl = ssl
         self._socket = None
+        self._reader = None
+        self._writer = None
         self._closed = asyncio.Event(loop=self._loop)
         self._closed.set()
 
@@ -111,6 +112,8 @@ class TcpClient:
                 self._socket.setblocking(False)
 
             self._closed.clear()
+            self._reader, self._writer =\
+                await asyncio.open_connection(sock=self._socket)
         except OSError as e:
             if e.errno in CONN_RESET_ERRNOS:
                 raise ConnectionResetError() from e
@@ -126,6 +129,9 @@ class TcpClient:
         """Closes the connection."""
         fd = None
         try:
+            if self._writer is not None:
+                self._writer.close()
+
             if self._socket is not None:
                 fd = self._socket.fileno()
                 if self.is_connected:
@@ -135,36 +141,12 @@ class TcpClient:
             pass  # Ignore ENOTCONN, EBADF, and any other error when closing
         finally:
             self._socket = None
+            self._reader = None
+            self._writer = None
             self._closed.set()
             if fd and fd != -1:
                 self._loop.remove_reader(fd)
 
-    async def _wait_timeout_or_close(self, coro):
-        """
-        Waits for the given coroutine to complete unless
-        the socket is closed or `self.timeout` expires.
-        """
-        done, running = await asyncio.wait(
-            [coro, self._closed.wait()],
-            timeout=self.timeout,
-            return_when=asyncio.FIRST_COMPLETED,
-            loop=self._loop
-        )
-        for r in running:
-            if not r.cancelled():
-                if r.done():
-                    # Retrieve exception to avoid "not retrieved" errors
-                    r.exception()
-
-                # Cancel the future despite its state
-                r.cancel()
-
-        if not self.is_connected:
-            raise self.SocketClosed()
-        if not done:
-            raise asyncio.TimeoutError()
-        return done.pop().result()
-
     async def write(self, data):
         """
         Writes (sends) the specified bytes to the connected peer.
@@ -173,13 +155,8 @@ class TcpClient:
         if not self.is_connected:
             raise ConnectionResetError('Not connected')
 
-        try:
+        self._writer.write(data)
-            await self._wait_timeout_or_close(self.sock_sendall(data))
+        await self._writer.drain()
-        except OSError as e:
-            if e.errno in CONN_RESET_ERRNOS:
-                raise ConnectionResetError() from e
-            else:
-                raise
 
     async def read(self, size):
         """
@@ -191,83 +168,4 @@ class TcpClient:
         if not self.is_connected:
             raise ConnectionResetError('Not connected')
 
-        with BytesIO() as buffer:
+        return await self._reader.readexactly(size)
-            bytes_left = size
-            while bytes_left != 0:
-                try:
-                    partial = await self._wait_timeout_or_close(
-                        self.sock_recv(bytes_left)
-                    )
-                except asyncio.TimeoutError:
-                    if bytes_left < size:
-                        __log__.warning(
-                            'Timeout when partial %d/%d had been received',
-                            size - bytes_left, size
-                        )
-                    raise
-                except OSError as e:
-                    if e.errno in CONN_RESET_ERRNOS:
-                        raise ConnectionResetError() from e
-                    else:
-                        raise
-
-                if not partial:
-                    raise ConnectionResetError()
-
-                buffer.write(partial)
-                bytes_left -= len(partial)
-
-            return buffer.getvalue()
-
-    # Due to recent https://github.com/python/cpython/pull/4386
-    # Credit to @andr-04 for his original implementation
-    def sock_recv(self, n):
-        fut = self._loop.create_future()
-        self._sock_recv(fut, None, n)
-        return fut
-
-    def _sock_recv(self, fut, registered_fd, n):
-        if registered_fd is not None:
-            self._loop.remove_reader(registered_fd)
-        if fut.cancelled() or self._socket is None:
-            return
-
-        try:
-            data = self._socket.recv(n)
-        except (BlockingIOError, InterruptedError):
-            fd = self._socket.fileno()
-            self._loop.add_reader(fd, self._sock_recv, fut, fd, n)
-        except Exception as exc:
-            fut.set_exception(exc)
-        else:
-            fut.set_result(data)
-
-    def sock_sendall(self, data):
-        fut = self._loop.create_future()
-        if data:
-            self._sock_sendall(fut, None, data)
-        else:
-            fut.set_result(None)
-        return fut
-
-    def _sock_sendall(self, fut, registered_fd, data):
-        if registered_fd:
-            self._loop.remove_writer(registered_fd)
-        if fut.cancelled() or self._socket is None:
-            return
-
-        try:
-            n = self._socket.send(data)
-        except (BlockingIOError, InterruptedError):
-            n = 0
-        except Exception as exc:
-            fut.set_exception(exc)
-            return
-
-        if n == len(data):
-            fut.set_result(None)
-        else:
-            if n:
-                data = data[n:]
-            fd = self._socket.fileno()
-            self._loop.add_writer(fd, self._sock_sendall, fut, fd, data)