Fix race condition allowing to run multiple instances at the same time (closes #286968)

src/misc.cpp

@@ -45,6 +45,11 @@
 
 #ifdef Q_WS_WIN
 #include <shlobj.h>
+#include <windows.h>
+const int UNLEN = 256;
+#else
+#include <unistd.h>
+#include <sys/types.h>
 #endif
 
 #ifdef Q_WS_MAC
@@ -485,6 +490,19 @@ QString misc::userFriendlyDuration(qlonglong seconds) {
   return QString::fromUtf8("∞");
 }
 
+QString misc::getUserIDString() {
+  QString uid = "0";
+#ifdef Q_WS_WIN
+  char buffer[UNLEN+1] = {0};
+  DWORD buffer_len = UNLEN + 1;
+  if (!GetUserNameA(buffer, &buffer_len))
+    uid = QString(buffer);
+#else
+  uid = QString::number(getuid());
+#endif
+  return uid;
+}
+
 QStringList misc::toStringList(const QList<bool> &l) {
   QStringList ret;
   foreach(const bool &b, l) {