worked on thread safety with tasks

app/common/CMakeLists.txt

@@ -26,6 +26,8 @@ set(OLIVE_SOURCES
   common/qobjectlistcast.h
   common/qtversionabstraction.h
   common/qtversionabstraction.cpp
+  common/threadedobject.h
+  common/threadedobject.cpp
   common/timecodefunctions.h
   common/timecodefunctions.cpp
   PARENT_SCOPE

app/common/threadedobject.cpp

@@ -0,0 +1,37 @@
+#include "threadedobject.h"
+
+ThreadedObject::ThreadedObject()
+{
+}
+
+void ThreadedObject::LockDeletes()
+{
+  threadobj_delete_lock_++;
+}
+
+void ThreadedObject::UnlockDeletes()
+{
+  Q_ASSERT(AreDeletesLocked());
+
+  threadobj_delete_lock_--;
+}
+
+bool ThreadedObject::AreDeletesLocked()
+{
+  return (threadobj_delete_lock_ > 0);
+}
+
+void ThreadedObject::LockMutex()
+{
+  threadobj_main_lock_.lock();
+}
+
+void ThreadedObject::UnlockMutex()
+{
+  threadobj_main_lock_.unlock();
+}
+
+bool ThreadedObject::TryLockMutex(int timeout)
+{
+  return threadobj_main_lock_.tryLock(timeout);
+}

app/common/threadedobject.h

@@ -0,0 +1,25 @@
+#ifndef THREADEDOBJECT_H
+#define THREADEDOBJECT_H
+
+#include <QMutex>
+
+class ThreadedObject
+{
+public:
+  ThreadedObject();
+
+  void LockMutex();
+  void UnlockMutex();
+  bool TryLockMutex(int timeout = 0);
+
+  void LockDeletes();
+  void UnlockDeletes();
+  bool AreDeletesLocked();
+
+private:
+  QMutex threadobj_main_lock_;
+
+  QAtomicInt threadobj_delete_lock_;
+};
+
+#endif // THREADEDOBJECT_H