Moved several files from pglab project to pglablib

pglablib/ASyncDBConnection.h

@@ -0,0 +1,91 @@
+#ifndef ASYNCDBCONNECTION_H
+#define ASYNCDBCONNECTION_H
+
+#include "Pgsql_Connection.h"
+#include "Pgsql_Params.h"
+#include "Pgsql_Result.h"
+#include "Expected.h"
+#include "ConnectionConfig.h"
+#include <QElapsedTimer>
+#include <functional>
+#include <mutex>
+#include <boost/asio/ip/tcp.hpp>
+#include <boost/asio/io_service.hpp>
+
+/** \brief Class that handles asynchronous execution of queries.
+ *
+ * Queries are passed to this class with a routine to call on completion
+ * when the result is received that routine is called. The asynchronous
+ * processing is done using boost::asio.
+ *
+ * You can cancel a running query but even then you have to wait for the result.
+ */
+class ASyncDBConnection {
+public:
+	enum class State {
+		NotConnected,
+		Connecting,
+		Connected, ///< connected and idle
+		QuerySend, ///< connected query send expecting result
+		CancelSend, ///< cancel send expecting result
+		Terminating ///< shutting down
+	};
+
+	using on_result_callback = std::function<void(Expected<std::shared_ptr<Pgsql::Result>>, qint64)>;
+
+	explicit ASyncDBConnection(boost::asio::io_service &ios);
+    ~ASyncDBConnection();
+
+	State state() const;
+	void setupConnection(const ConnectionConfig &config);
+	void closeConnection();
+
+	/** \defgroup send These function send queries to the server.
+	 *
+	 * The query string can actually contain multiple queries.
+	 * These functions report their results through a callback function.
+	 * If the command gives multiple results on_result will be called for each result.
+	 *
+	 * \note when the io_service that was passed to the constructor is running
+	 * on a different thread the callback also will be done on that thread. Forward
+	 * the call to your own thread if needed.
+	 *
+	 * \note while you can pass multiple queries to a single send call it is not allowed to
+	 *   send new queries while not all results have been received.
+	 */
+
+	/** \ingroup send
+	 * \brief Function to send a command without parameters to the server.
+	 */
+	bool send(const std::string &command, on_result_callback on_result);
+	/** \ingroup send
+	 * \brief Function to send a a command with parameters to the server.
+	 */
+	bool send(const std::string &command, Pgsql::Params params, on_result_callback on_result);
+
+	bool cancel();
+    
+	using StateChangeReceiver = std::function<void(ASyncDBConnection::State)>;
+	void setStateChangeReceiver(StateChangeReceiver state_change_receiver);
+
+	using NoticeReceiver = std::function<void(Pgsql::ErrorDetails)>;
+	void setNoticeReceiver(NoticeReceiver notice_receiver);
+
+private:
+	Pgsql::Connection m_connection;
+    boost::asio::ip::tcp::socket m_asioSock;
+	ConnectionConfig m_config;
+	State m_state = State::NotConnected;
+    Pgsql::Canceller m_canceller;
+	StateChangeReceiver m_stateChangeReceiver;
+	NoticeReceiver m_noticeReceiver;
+
+    QElapsedTimer m_timer;
+    
+    void async_connect_handler(boost::system::error_code ec, std::size_t s);
+    void async_query_handler(boost::system::error_code ec, std::size_t s, on_result_callback on_result);
+    void doStateCallback(State state);
+    void processNotice(const PGresult *result);
+};
+
+#endif // ASYNCDBCONNECTION_H