logic: correctly undoing graph interactions by replaying actions since last active token change

This change introdoces a classification of commands by order in the undo stack. Undoing the last action will resend the
message of the last active token change and all messages changing the ui after that.

src/lib/utility/scheduling/Task.cpp

@@ -8,6 +8,11 @@ void Task::dispatch(std::shared_ptr<Task> task)
 	TaskScheduler::getInstance()->pushTask(task);
 }
 
+void Task::dispatchNext(std::shared_ptr<Task> task)
+{
+	TaskScheduler::getInstance()->pushNextTask(task);
+}
+
 Task::Task()
 	: m_state(STATE_NEW)
 {

src/lib/utility/scheduling/Task.h

@@ -15,6 +15,7 @@ public:
 	};
 
 	static void dispatch(std::shared_ptr<Task> task);
+	static void dispatchNext(std::shared_ptr<Task> task);
 
 	Task();
 	virtual ~Task();

src/lib/utility/scheduling/TaskScheduler.cpp

@@ -19,7 +19,13 @@ std::shared_ptr<TaskScheduler> TaskScheduler::getInstance()
 void TaskScheduler::pushTask(std::shared_ptr<Task> task)
 {
 	std::lock_guard<std::mutex> lock(m_tasksMutex);
-	m_tasks.push(task);
+	m_tasks.push_back(task);
+}
+
+void TaskScheduler::pushNextTask(std::shared_ptr<Task> task)
+{
+	std::lock_guard<std::mutex> lock(m_tasksMutex);
+	m_tasks.push_front(task);
 }
 
 void TaskScheduler::interruptCurrentTask()
@@ -136,14 +142,15 @@ void TaskScheduler::updateTasks()
 	while (m_tasks.size())
 	{
 		std::shared_ptr<Task> task = m_tasks.front();
+		m_tasks.pop_front();
 
 		m_tasksMutex.unlock();
 		Task::TaskState state = task->process(interrupt);
 		m_tasksMutex.lock();
 
-		if (state == Task::STATE_FINISHED || state == Task::STATE_CANCELED)
+		if (state != Task::STATE_FINISHED && state != Task::STATE_CANCELED)
 		{
-			m_tasks.pop();
+			m_tasks.push_front(task);
 		}
 
 		interrupt = m_interruptTask;

src/lib/utility/scheduling/TaskScheduler.h

@@ -3,7 +3,7 @@
 
 #include <memory>
 #include <mutex>
-#include <queue>
+#include <deque>
 
 #include "utility/messaging/MessageListener.h"
 #include "utility/messaging/type/MessageInterruptTasks.h"
@@ -16,6 +16,7 @@ public:
 	static std::shared_ptr<TaskScheduler> getInstance();
 
 	void pushTask(std::shared_ptr<Task> task);
+	void pushNextTask(std::shared_ptr<Task> task);
 	void interruptCurrentTask();
 
 	void startSchedulerLoopThreaded();
@@ -39,7 +40,7 @@ private:
 	bool m_loopIsRunning;
 	bool m_threadIsRunning;
 
-	std::queue<std::shared_ptr<Task>> m_tasks;
+	std::deque<std::shared_ptr<Task>> m_tasks;
 	bool m_interruptTask;
 
 	mutable std::mutex m_tasksMutex;