Change Windows version to pass SOCKET handles to libev.

One has to use the corresponding change in the ArangoDB-Windows
repository as well, where libev is patched for this purpose.

lib/BasicsC/socket-utils.c

@@ -73,14 +73,19 @@ int TRI_closesocket (TRI_socket_t s) {
     if (res != 0) {
       LOG_WARNING("socket close error: %d", WSAGetLastError());
     }
-    if (s.fileDescriptor != -1) {
-      res = _close(s.fileDescriptor);
-      /*
-      To close a file opened with _open_osfhandle, call _close.
-      The underlying handle is also closed by a call to _close,
-      so it is not necessary to call the Win32 function CloseHandle on the original handle.
-      */
-    }
+    // We patch libev on Windows lightly to not really distinguish between
+    // socket handles and file descriptors, therefore, we do not have to do the 
+    // following any more:
+    // if (s.fileDescriptor != -1) {
+    //   res = _close(s.fileDescriptor);
+         // "To close a file opened with _open_osfhandle, call _close."
+         // The underlying handle is also closed by a call to _close,
+         // so it is not necessary to call the Win32 function CloseHandle 
+         // on the original handle.
+    // However, we do want to do the special shutdown/recv magic above
+    // because only then we can reuse the port quickly, which we want
+    // to do directly after a port test.
+    // }
   }
 #else
     if (s.fileDescriptor != TRI_INVALID_SOCKET) {

lib/Scheduler/ListenTask.cpp

@@ -113,7 +113,13 @@ bool ListenTask::setup (Scheduler* scheduler, EventLoop loop) {
     return false;
   }
 
-  int res = _open_osfhandle (_listenSocket.fileHandle, 0);
+  // For the official version of libev we would do this:
+  // int res = _open_osfhandle (_listenSocket.fileHandle, 0);
+  // However, this opens a whole lot of problems and in general one should
+  // never use _open_osfhandle for sockets.
+  // Therefore, we do the following, although it has the potential to
+  // lose the higher bits of the socket handle:
+  int res = (int)_listenSocket.fileHandle;
 
   if (res == - 1) {
     LOG_ERROR("In ListenTask::setup could not convert socket handle to socket descriptor -- _open_osfhandle(...) failed");

lib/Scheduler/SocketTask.cpp

@@ -429,7 +429,13 @@ bool SocketTask::setup (Scheduler* scheduler, EventLoop loop) {
     return false;
   }
 
-  int res = _open_osfhandle(_commSocket.fileHandle, 0);
+  // For the official version of libev we would do this:
+  // int res = _open_osfhandle(_commSocket.fileHandle, 0);
+  // However, this opens a whole lot of problems and in general one should
+  // never use _open_osfhandle for sockets.
+  // Therefore, we do the following, although it has the potential to
+  // lose the higher bits of the socket handle:
+  int res = (int)_commSocket.fileHandle;
 
   if (res == -1) {
     LOG_ERROR("In SocketTask::setup could not convert socket handle to socket descriptor -- _open_osfhandle(...) failed");