Work in progress: Good bye, Perl Threads!

xs/src/slic3r/GUI/BackgroundSlicingProcess.hpp

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+#ifndef slic3r_GUI_BackgroundSlicingProcess_hpp_
+#define slic3r_GUI_BackgroundSlicingProcess_hpp_
+
+#include <string>
+#include <condition_variable>
+#include <mutex>
+#include <thread>
+
+namespace Slic3r {
+
+class DynamicPrintConfig;
+class GCodePreviewData;
+class Print;
+
+// Support for the GUI background processing (Slicing and G-code generation).
+// As of now this class is not declared in Slic3r::GUI due to the Perl bindings limits.
+class BackgroundSlicingProcess
+{
+public:
+	BackgroundSlicingProcess() {}
+	~BackgroundSlicingProcess() { this->stop(); this->join_background_thread(); }
+
+	void set_print(Print *print) { m_print = print; }
+	void set_gcode_preview_data(GCodePreviewData *gpd) { m_gcode_preview_data = gpd; }
+	void set_sliced_event(int event_id) { m_event_sliced_id = event_id; }
+	void set_finished_event(int event_id) { m_event_finished_id = event_id; }
+
+	// Start the background processing. Returns false if the background processing was already running.
+	bool start();
+	// Cancel the background processing. Returns false if the background processing was not running.
+	// A stopped background processing may be restarted with start().
+	bool stop();
+
+	// Apply config over the print. Returns false, if the new config values caused any of the already
+	// processed steps to be invalidated, therefore the task will need to be restarted.
+	bool apply_config(DynamicPrintConfig *config);
+
+	enum State {
+		// m_thread  is not running yet, or it did not reach the STATE_IDLE yet (it does not wait on the condition yet).
+		STATE_INITIAL = 0,
+		// m_thread is waiting for the task to execute.
+		STATE_IDLE,
+		STATE_STARTED,
+		// m_thread is executing a task.
+		STATE_RUNNING,
+		// m_thread finished executing a task, and it is waiting until the UI thread picks up the results.
+		STATE_FINISHED,
+		// m_thread finished executing a task, the task has been canceled by the UI thread, therefore the UI thread will not be notified.
+		STATE_CANCELED,
+		// m_thread exited the loop and it is going to finish. The UI thread should join on m_thread.
+		STATE_EXIT,
+		STATE_EXITED,
+	};
+	State 	state() 	const { return m_state; }
+	bool    idle() 		const { return m_state == STATE_IDLE; }
+	bool    running() 	const { return m_state == STATE_STARTED || m_state == STATE_RUNNING || m_state == STATE_FINISHED || m_state == STATE_CANCELED; }
+
+private:
+	void 	thread_proc();
+	void 	start_background_thread();
+	void 	join_background_thread();
+
+	Print 					   *m_print 			 = nullptr;
+	GCodePreviewData 		   *m_gcode_preview_data = nullptr;
+	std::string 				m_output_path;
+	// Thread, on which the background processing is executed. The thread will always be present
+	// and ready to execute the slicing process.
+	std::thread		 			m_thread;
+	// Mutex and condition variable to synchronize m_thread with the UI thread.
+	std::mutex 		 			m_mutex;
+	std::condition_variable		m_condition;
+	State 						m_state = STATE_INITIAL;
+
+	// wxWidgets command ID to be sent to the platter to inform that the slicing is finished, and the G-code export will continue.
+	int 						m_event_sliced_id 	 = 0;
+	// wxWidgets command ID to be sent to the platter to inform that the task finished.
+	int 						m_event_finished_id  = 0;
+};
+
+}; // namespace Slic3r
+
+#endif /* slic3r_GUI_BackgroundSlicingProcess_hpp_ */