ui: file clearing progress

* display some progress information when clearing files

src/lib/data/TaskShowStatusDialog.h

@@ -0,0 +1,33 @@
+#ifndef TASK_SHOW_STATUS_DIALOG_H
+#define TASK_SHOW_STATUS_DIALOG_H
+
+#include <string>
+
+#include "utility/scheduling/Task.h"
+
+class DialogView;
+
+class TaskShowStatusDialog
+	: public Task
+{
+public:
+	TaskShowStatusDialog(
+		const std::string& title,
+		const std::string& message,
+		DialogView* dialogView
+	);
+
+	virtual ~TaskShowStatusDialog();
+
+private:
+	virtual void doEnter(std::shared_ptr<Blackboard> blackboard);
+	virtual TaskState doUpdate(std::shared_ptr<Blackboard> blackboard);
+	virtual void doExit(std::shared_ptr<Blackboard> blackboard);
+	virtual void doReset(std::shared_ptr<Blackboard> blackboard);
+
+	const std::string m_title;
+	const std::string m_message;
+	DialogView* m_dialogView;
+};
+
+#endif // TASK_SHOW_STATUS_DIALOG_H