pgLab/asyncdbconnection.h

#ifndef ASYNCDBCONNECTION_H
#define ASYNCDBCONNECTION_H

#include "PgsqlConn.h"
#include "win32event.h"
#include <functional>
#include <mutex>
#include <vector>
#include <thread>

class ASyncDBConnection {
public:
	enum class State {
		NotConnected,
		Connecting,
		Connected,
		QuerySend,
		CancelSend
	};

	using on_result_callback = std::function<void(Pgsql::Result)>;
	using on_state_callback = std::function<void(State)>;

	ASyncDBConnection();

	void setupConnection(const std::string &connstring);
	void closeConnection();

	void setStateCallback(on_state_callback state_callback);

	/** Sends command to the server.

	When the result is in and no result_task_queue was passed then on_result will be
	called directly within the thread.

	If the command gives multiple results on_result will be called for each result.
	*/
	bool send(const std::string &command, on_result_callback on_result);

private:

	class Command {
	public:
		std::string command;
		on_result_callback on_result;
	};

	/// Contains all the members accessed by the thread
	class Thread {
	public:
		on_state_callback m_stateCallback;
		std::mutex m_stateCallbackMutex;

		std::string m_initString;

		Thread();

		/// Is started as a seperate thread by ASyncDBConnection
		void run();

		/// Sends a cancel request to the DB server
		void cancel();

		void stop();

	private:

		Win32Event m_stopEvent;
		Pgsql::Connection m_connection;
		bool terminateRequested = false; ///< is set when the thread should stop


		bool makeConnection();
		void communicate();

		void doStateCallback(State state);
	};

	Thread m_threadData;
	std::thread m_thread;
};

#endif // ASYNCDBCONNECTION_H