Merge 3.4 (asyncio)

Lib/asyncio/windows_events.py

@@ -257,7 +257,7 @@ class PipeServer(object):
 
     def _server_pipe_handle(self, first):
         # Return a wrapper for a new pipe handle.
-        if self._address is None:
+        if self.closed():
             return None
         flags = _winapi.PIPE_ACCESS_DUPLEX | _winapi.FILE_FLAG_OVERLAPPED
         if first:
@@ -273,6 +273,9 @@ class PipeServer(object):
         self._free_instances.add(pipe)
         return pipe
 
+    def closed(self):
+        return (self._address is None)
+
     def close(self):
         if self._accept_pipe_future is not None:
             self._accept_pipe_future.cancel()
@@ -325,12 +328,21 @@ class ProactorEventLoop(proactor_events.BaseProactorEventLoop):
                 if f:
                     pipe = f.result()
                     server._free_instances.discard(pipe)
+
+                    if server.closed():
+                        # A client connected before the server was closed:
+                        # drop the client (close the pipe) and exit
+                        pipe.close()
+                        return
+
                     protocol = protocol_factory()
                     self._make_duplex_pipe_transport(
                         pipe, protocol, extra={'addr': address})
+
                 pipe = server._get_unconnected_pipe()
                 if pipe is None:
                     return
+
                 f = self._proactor.accept_pipe(pipe)
             except OSError as exc:
                 if pipe and pipe.fileno() != -1:
@@ -506,28 +518,25 @@ class IocpProactor:
 
         return self._register(ov, pipe, finish_accept_pipe)
 
-    def _connect_pipe(self, fut, address, delay):
-        # Unfortunately there is no way to do an overlapped connect to a pipe.
-        # Call CreateFile() in a loop until it doesn't fail with
-        # ERROR_PIPE_BUSY
-        try:
-            handle = _overlapped.ConnectPipe(address)
-        except OSError as exc:
-            if exc.winerror == _overlapped.ERROR_PIPE_BUSY:
-                # Polling: retry later
-                delay = min(delay * 2, CONNECT_PIPE_MAX_DELAY)
-                self._loop.call_later(delay,
-                                      self._connect_pipe, fut, address, delay)
-            else:
-                fut.set_exception(exc)
-        else:
-            pipe = windows_utils.PipeHandle(handle)
-            fut.set_result(pipe)
-
+    @coroutine
     def connect_pipe(self, address):
-        fut = futures.Future(loop=self._loop)
-        self._connect_pipe(fut, address, CONNECT_PIPE_INIT_DELAY)
-        return fut
+        delay = CONNECT_PIPE_INIT_DELAY
+        while True:
+            # Unfortunately there is no way to do an overlapped connect to a pipe.
+            # Call CreateFile() in a loop until it doesn't fail with
+            # ERROR_PIPE_BUSY
+            try:
+                handle = _overlapped.ConnectPipe(address)
+                break
+            except OSError as exc:
+                if exc.winerror != _overlapped.ERROR_PIPE_BUSY:
+                    raise
+
+            # ConnectPipe() failed with ERROR_PIPE_BUSY: retry later
+            delay = min(delay * 2, CONNECT_PIPE_MAX_DELAY)
+            yield from tasks.sleep(delay, loop=self._loop)
+
+        return windows_utils.PipeHandle(handle)
 
     def wait_for_handle(self, handle, timeout=None):
         """Wait for a handle.

Lib/asyncio/windows_utils.py

@@ -147,6 +147,8 @@ class PipeHandle:
         return self._handle
 
     def fileno(self):
+        if self._handle is None:
+            raise ValueError("I/O operatioon on closed pipe")
         return self._handle
 
     def close(self, *, CloseHandle=_winapi.CloseHandle):

Lib/test/test_asyncio/test_windows_events.py

@@ -1,6 +1,7 @@
 import os
 import sys
 import unittest
+from unittest import mock
 
 if sys.platform != 'win32':
     raise unittest.SkipTest('Windows only')
@@ -91,6 +92,18 @@ class ProactorTests(test_utils.TestCase):
 
         return 'done'
 
+    def test_connect_pipe_cancel(self):
+        exc = OSError()
+        exc.winerror = _overlapped.ERROR_PIPE_BUSY
+        with mock.patch.object(_overlapped, 'ConnectPipe', side_effect=exc) as connect:
+            coro = self.loop._proactor.connect_pipe('pipe_address')
+            task = self.loop.create_task(coro)
+
+            # check that it's possible to cancel connect_pipe()
+            task.cancel()
+            with self.assertRaises(asyncio.CancelledError):
+                self.loop.run_until_complete(task)
+
     def test_wait_for_handle(self):
         event = _overlapped.CreateEvent(None, True, False, None)
         self.addCleanup(_winapi.CloseHandle, event)