bpo-32622: Native sendfile on windows (#5565)

* Support sendfile on Windows Proactor event loop naively.

Lib/test/test_asyncio/test_proactor_events.py

@@ -1,14 +1,18 @@
 """Tests for proactor_events.py"""
 
+import io
 import socket
 import unittest
+import sys
 from unittest import mock
 
 import asyncio
+from asyncio import events
 from asyncio.proactor_events import BaseProactorEventLoop
 from asyncio.proactor_events import _ProactorSocketTransport
 from asyncio.proactor_events import _ProactorWritePipeTransport
 from asyncio.proactor_events import _ProactorDuplexPipeTransport
+from test import support
 from test.test_asyncio import utils as test_utils
 
 
@@ -775,5 +779,117 @@ class BaseProactorEventLoopTests(test_utils.TestCase):
         self.assertFalse(future2.cancel.called)
 
 
+@unittest.skipIf(sys.platform != 'win32',
+                 'Proactor is supported on Windows only')
+class ProactorEventLoopUnixSockSendfileTests(test_utils.TestCase):
+    DATA = b"12345abcde" * 16 * 1024  # 160 KiB
+
+    class MyProto(asyncio.Protocol):
+
+        def __init__(self, loop):
+            self.started = False
+            self.closed = False
+            self.data = bytearray()
+            self.fut = loop.create_future()
+            self.transport = None
+
+        def connection_made(self, transport):
+            self.started = True
+            self.transport = transport
+
+        def data_received(self, data):
+            self.data.extend(data)
+
+        def connection_lost(self, exc):
+            self.closed = True
+            self.fut.set_result(None)
+
+        async def wait_closed(self):
+            await self.fut
+
+    @classmethod
+    def setUpClass(cls):
+        with open(support.TESTFN, 'wb') as fp:
+            fp.write(cls.DATA)
+        super().setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        support.unlink(support.TESTFN)
+        super().tearDownClass()
+
+    def setUp(self):
+        self.loop = asyncio.ProactorEventLoop()
+        self.set_event_loop(self.loop)
+        self.addCleanup(self.loop.close)
+        self.file = open(support.TESTFN, 'rb')
+        self.addCleanup(self.file.close)
+        super().setUp()
+
+    def make_socket(self, cleanup=True):
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        sock.setblocking(False)
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_SNDBUF, 1024)
+        sock.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, 1024)
+        if cleanup:
+            self.addCleanup(sock.close)
+        return sock
+
+    def run_loop(self, coro):
+        return self.loop.run_until_complete(coro)
+
+    def prepare(self):
+        sock = self.make_socket()
+        proto = self.MyProto(self.loop)
+        port = support.find_unused_port()
+        srv_sock = self.make_socket(cleanup=False)
+        srv_sock.bind(('127.0.0.1', port))
+        server = self.run_loop(self.loop.create_server(
+            lambda: proto, sock=srv_sock))
+        self.run_loop(self.loop.sock_connect(sock, srv_sock.getsockname()))
+
+        def cleanup():
+            if proto.transport is not None:
+                # can be None if the task was cancelled before
+                # connection_made callback
+                proto.transport.close()
+                self.run_loop(proto.wait_closed())
+
+            server.close()
+            self.run_loop(server.wait_closed())
+
+        self.addCleanup(cleanup)
+
+        return sock, proto
+
+    def test_sock_sendfile_not_a_file(self):
+        sock, proto = self.prepare()
+        f = object()
+        with self.assertRaisesRegex(events.SendfileNotAvailableError,
+                                    "not a regular file"):
+            self.run_loop(self.loop._sock_sendfile_native(sock, f,
+                                                          0, None))
+        self.assertEqual(self.file.tell(), 0)
+
+    def test_sock_sendfile_iobuffer(self):
+        sock, proto = self.prepare()
+        f = io.BytesIO()
+        with self.assertRaisesRegex(events.SendfileNotAvailableError,
+                                    "not a regular file"):
+            self.run_loop(self.loop._sock_sendfile_native(sock, f,
+                                                          0, None))
+        self.assertEqual(self.file.tell(), 0)
+
+    def test_sock_sendfile_not_regular_file(self):
+        sock, proto = self.prepare()
+        f = mock.Mock()
+        f.fileno.return_value = -1
+        with self.assertRaisesRegex(events.SendfileNotAvailableError,
+                                    "not a regular file"):
+            self.run_loop(self.loop._sock_sendfile_native(sock, f,
+                                                          0, None))
+        self.assertEqual(self.file.tell(), 0)
+
+
 if __name__ == '__main__':
     unittest.main()