23e307f93a
While I like some aspects of Qt's signals and slots system I prefer to rely on more standard C++.
91 lines
3 KiB
C++
91 lines
3 KiB
C++
#ifndef ASYNCDBCONNECTION_H
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#define ASYNCDBCONNECTION_H
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#include "Pgsql_Connection.h"
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#include "Pgsql_Params.h"
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#include "Pgsql_Result.h"
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#include "Expected.h"
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#include "ConnectionConfig.h"
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#include <QElapsedTimer>
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#include <functional>
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#include <mutex>
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#include <boost/asio/ip/tcp.hpp>
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#include <boost/asio/io_service.hpp>
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/** \brief Class that handles asynchronous execution of queries.
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*
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* Queries are passed to this class with a routine to call on completion
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* when the result is received that routine is called. The asynchronous
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* processing is done using boost::asio.
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*
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* You can cancel a running query but even then you have to wait for the result.
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*/
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class ASyncDBConnection {
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public:
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enum class State {
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NotConnected,
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Connecting,
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Connected, ///< connected and idle
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QuerySend, ///< connected query send expecting result
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CancelSend, ///< cancel send expecting result
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Terminating ///< shutting down
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};
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using on_result_callback = std::function<void(Expected<std::shared_ptr<Pgsql::Result>>, qint64)>;
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explicit ASyncDBConnection(boost::asio::io_service &ios);
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~ASyncDBConnection();
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State state() const;
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void setupConnection(const ConnectionConfig &config);
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void closeConnection();
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/** \defgroup send These function send queries to the server.
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*
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* The query string can actually contain multiple queries.
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* These functions report their results through a callback function.
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* If the command gives multiple results on_result will be called for each result.
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*
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* \note when the io_service that was passed to the constructor is running
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* on a different thread the callback also will be done on that thread. Forward
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* the call to your own thread if needed.
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*
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* \note while you can pass multiple queries to a single send call it is not allowed to
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* send new queries while not all results have been received.
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*/
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/** \ingroup send
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* \brief Function to send a command without parameters to the server.
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*/
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bool send(const std::string &command, on_result_callback on_result);
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/** \ingroup send
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* \brief Function to send a a command with parameters to the server.
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*/
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bool send(const std::string &command, Pgsql::Params params, on_result_callback on_result);
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bool cancel();
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using StateChangeReceiver = std::function<void(ASyncDBConnection::State)>;
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void setStateChangeReceiver(StateChangeReceiver state_change_receiver);
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using NoticeReceiver = std::function<void(Pgsql::ErrorDetails)>;
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void setNoticeReceiver(NoticeReceiver notice_receiver);
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private:
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Pgsql::Connection m_connection;
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boost::asio::ip::tcp::socket m_asioSock;
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ConnectionConfig m_config;
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State m_state = State::NotConnected;
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Pgsql::Canceller m_canceller;
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StateChangeReceiver m_stateChangeReceiver;
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NoticeReceiver m_noticeReceiver;
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QElapsedTimer m_timer;
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void async_connect_handler(boost::system::error_code ec, std::size_t s);
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void async_query_handler(boost::system::error_code ec, std::size_t s, on_result_callback on_result);
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void doStateCallback(State state);
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void processNotice(const PGresult *result);
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};
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#endif // ASYNCDBCONNECTION_H
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