[libcalamares] Move kdsingleapplicationguard to 3rdparty

3rdparty/kdsingleapplicationguard/kdsharedmemorylocker.cpp

@@ -0,0 +1,40 @@
+#include "kdsharedmemorylocker.h"
+
+#if QT_VERSION >= 0x040400 || defined( DOXYGEN_RUN )
+
+#include <QSharedMemory>
+
+using namespace kdtools;
+
+/*!
+  \class KDSharedMemoryLocker
+  \ingroup raii core
+  \brief Exception-safe and convenient wrapper around QSharedMemory::lock()
+*/
+
+/**
+ * Constructor. Locks the shared memory segment \a mem.
+ * If another process has locking the segment, this constructor blocks
+ * until the lock is released. The memory segments needs to be properly created or attached.
+ */
+KDSharedMemoryLocker::KDSharedMemoryLocker( QSharedMemory* mem )
+    : mem( mem )
+{
+    mem->lock();
+}
+
+/**
+ * Destructor. Unlocks the shared memory segment associated with this
+ * KDSharedMemoryLocker.
+ */
+KDSharedMemoryLocker::~KDSharedMemoryLocker()
+{
+    mem->unlock();
+}
+
+#ifdef KDAB_EVAL
+#include KDAB_EVAL
+static const EvalDialogChecker evalChecker( "KD Tools", false );
+#endif
+
+#endif