Fixed mishandling of large buffers in BaseSocket.sendall()

Fixes #38.

Author: agronholm

anyio/_networking.py

@@ -143,20 +143,20 @@ async def sendto(self, data: bytes, addr, *, flags: int = 0) -> int:
             return self._raw_socket.sendto(data, flags, addr)
 
     async def sendall(self, data: bytes, *, flags: int = 0) -> None:
-        to_send = len(data)
-        while to_send > 0:
+        offset = 0
+        total = len(data)
+        buffer = memoryview(data)
+        while offset < total:
             await self._check_cancelled()
             try:
-                sent = self._raw_socket.send(data, flags)
+                offset += self._raw_socket.send(buffer[offset:], flags)
             except (BlockingIOError, ssl.SSLWantWriteError):
                 await self._wait_writable()
             except ssl.SSLWantReadError:
                 await self._wait_readable()
             except ssl.SSLEOFError:
                 self._raw_socket.close()
                 raise
-            else:
-                to_send -= sent
 
     async def start_tls(self, context: ssl.SSLContext,
                         server_hostname: Optional[str] = None,

docs/versionhistory.rst

@@ -3,6 +3,10 @@ Version history
 
 This library adheres to `Semantic Versioning <http://semver.org/>`_.
 
+**UNRELEASED**
+
+- Fixed mishandling of large buffers by ``BaseSocket.sendall()``
+
 **1.0.0b1**
 
 - Initial release

tests/test_networking.py

@@ -72,6 +72,23 @@ async def server():
 
         assert response == b'blahbleh'
 
+    @pytest.mark.anyio
+    async def test_send_large_buffer(self):
+        async def server():
+            async with await stream_server.accept() as stream:
+                await stream.send_all(buffer)
+
+        buffer = b'\xff' * 1024  # should exceed the maximum kernel send buffer size
+        async with create_task_group() as tg:
+            async with await create_tcp_server(interface='localhost') as stream_server:
+                await tg.spawn(server)
+                async with await connect_tcp('localhost', stream_server.port) as client:
+                    response = await client.receive_exactly(len(buffer))
+                    with pytest.raises(IncompleteRead):
+                        await client.receive_exactly(1)
+
+        assert response == buffer
+
     @pytest.mark.parametrize('method_name, params', [
         ('receive_until', [b'\n', 100]),
         ('receive_exactly', [5])