bpo-32251: Implement asyncio.BufferedProtocol. (#4755)

Lib/asyncio/selector_events.py

@@ -22,8 +22,9 @@ from . import base_events
 from . import constants
 from . import events
 from . import futures
-from . import transports
+from . import protocols
 from . import sslproto
+from . import transports
 from .log import logger
 
 
@@ -713,6 +714,12 @@ class _SelectorSocketTransport(_SelectorTransport):
 
     def __init__(self, loop, sock, protocol, waiter=None,
                  extra=None, server=None):
+
+        if protocols._is_buffered_protocol(protocol):
+            self._read_ready = self._read_ready__get_buffer
+        else:
+            self._read_ready = self._read_ready__data_received
+
         super().__init__(loop, sock, protocol, extra, server)
         self._eof = False
         self._paused = False
@@ -751,29 +758,74 @@ class _SelectorSocketTransport(_SelectorTransport):
         if self._loop.get_debug():
             logger.debug("%r resumes reading", self)
 
-    def _read_ready(self):
+    def _read_ready__get_buffer(self):
+        if self._conn_lost:
+            return
+
+        try:
+            buf = self._protocol.get_buffer()
+        except Exception as exc:
+            self._fatal_error(
+                exc, 'Fatal error: protocol.get_buffer() call failed.')
+            return
+
+        try:
+            nbytes = self._sock.recv_into(buf)
+        except (BlockingIOError, InterruptedError):
+            return
+        except Exception as exc:
+            self._fatal_error(exc, 'Fatal read error on socket transport')
+            return
+
+        if not nbytes:
+            self._read_ready__on_eof()
+            return
+
+        try:
+            self._protocol.buffer_updated(nbytes)
+        except Exception as exc:
+            self._fatal_error(
+                exc, 'Fatal error: protocol.buffer_updated() call failed.')
+
+    def _read_ready__data_received(self):
         if self._conn_lost:
             return
         try:
             data = self._sock.recv(self.max_size)
         except (BlockingIOError, InterruptedError):
-            pass
+            return
         except Exception as exc:
             self._fatal_error(exc, 'Fatal read error on socket transport')
+            return
+
+        if not data:
+            self._read_ready__on_eof()
+            return
+
+        try:
+            self._protocol.data_received(data)
+        except Exception as exc:
+            self._fatal_error(
+                exc, 'Fatal error: protocol.data_received() call failed.')
+
+    def _read_ready__on_eof(self):
+        if self._loop.get_debug():
+            logger.debug("%r received EOF", self)
+
+        try:
+            keep_open = self._protocol.eof_received()
+        except Exception as exc:
+            self._fatal_error(
+                exc, 'Fatal error: protocol.eof_received() call failed.')
+            return
+
+        if keep_open:
+            # We're keeping the connection open so the
+            # protocol can write more, but we still can't
+            # receive more, so remove the reader callback.
+            self._loop._remove_reader(self._sock_fd)
         else:
-            if data:
-                self._protocol.data_received(data)
-            else:
-                if self._loop.get_debug():
-                    logger.debug("%r received EOF", self)
-                keep_open = self._protocol.eof_received()
-                if keep_open:
-                    # We're keeping the connection open so the
-                    # protocol can write more, but we still can't
-                    # receive more, so remove the reader callback.
-                    self._loop._remove_reader(self._sock_fd)
-                else:
-                    self.close()
+            self.close()
 
     def write(self, data):
         if not isinstance(data, (bytes, bytearray, memoryview)):