QNativeSocketEngine on Windows: don't bail out on non-fatal error

receiving the WSAEMSGSIZE error means we could not read all the data
because the buffer was too small, but still we should return the number
of bytes read and not return -1

Reviewed-by: Marius Storm-Olsen

1 files changed, 9 insertions, 3 deletions

diff --git a/src/network/socket/qnativesocketengine_win.cpp b/src/network/socket/qnativesocketengine_win.cpp
index 3478130..63fe78e 100644
--- a/src/network/socket/qnativesocketengine_win.cpp
+++ b/src/network/socket/qnativesocketengine_win.cpp
@@ -917,9 +917,15 @@ qint64 QNativeSocketEnginePrivate::nativeReceiveDatagram(char *data, qint64 maxL
     int wsaRet = ::WSARecvFrom(socketDescriptor, &buf, 1, &bytesRead, &flags, &aa.a, &sz,0,0);
     if (wsaRet == SOCKET_ERROR) {
         int err = WSAGetLastError();
-        WS_ERROR_DEBUG(err);
-        setError(QAbstractSocket::NetworkError, ReceiveDatagramErrorString);
-        ret = -1;
+        if (err == WSAEMSGSIZE) {
+            // it is ok the buffer was to small if bytesRead is larger than
+            // maxLength then assume bytes read is really maxLenth
+            ret = qint64(bytesRead) > maxLength ? maxLength : qint64(bytesRead);
+        } else {
+            WS_ERROR_DEBUG(err);
+            setError(QAbstractSocket::NetworkError, ReceiveDatagramErrorString);
+            ret = -1;
+        }
     } else {
         ret = qint64(bytesRead);
     }