don't close UDP socket if it receives an empty datagram (patch 1885472)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@51623 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/changes.txt

@@ -121,6 +121,7 @@ All (Unix):
 - Fixed shared libraries to not depend on GStreamer when built with
   --enable-media; only wxMedia library depends on it now.
 - wxLaunchDefaultBrowser() now uses xdg-open if available.
+- Don't close UDP socket if an empty datagram is received (Mikkel S)
 
 wxMSW:
 

src/unix/gsocket.cpp

@@ -1175,11 +1175,16 @@ int GSocket::Read(char *buffer, int size)
     else
       ret = Recv_Dgram(buffer, size);
 
-    /* If recv returned zero, then the connection has been gracefully closed.
+    /*
-     * Otherwise, recv has returned an error (-1), in which case we have lost the
+     * If recv returned zero for a TCP socket (if m_stream == NULL, it's an UDP
-     * socket only if errno does _not_ indicate that there may be more data to read.
+     * socket and empty datagrams are possible), then the connection has been
+     * gracefully closed.
+     *
+     * Otherwise, recv has returned an error (-1), in which case we have lost
+     * the socket only if errno does _not_ indicate that there may be more data
+     * to read.
      */
-    if (ret == 0)
+    if ((ret == 0) && m_stream)
     {
       /* Make sure wxSOCKET_LOST event gets sent and shut down the socket */
       m_detected = GSOCK_LOST_FLAG;
@@ -1760,9 +1765,17 @@ void GSocket::Detected_Read()
     }
     else if (num == 0)
     {
-      /* graceful shutdown */
+      if (m_stream)
-      CALL_CALLBACK(this, GSOCK_LOST);
+      {
-      Shutdown();
+        /* graceful shutdown */
+        CALL_CALLBACK(this, GSOCK_LOST);
+        Shutdown();
+      }
+      else
+      {
+        /* Empty datagram received */
+        CALL_CALLBACK(this, GSOCK_INPUT);
+      }
     }
     else
     {