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The ASyncDBConnection class uses C++ std::function callbacks now for reporting notices and state changes.

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While I like some aspects of Qt's signals and slots system I prefer to
rely on more standard C++.
This commit is contained in:
eelke 2017-12-28 07:28:21 +01:00
parent 2705a3417b
commit 23e307f93a
4 changed files with 67 additions and 36 deletions
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51
pglab/ASyncDBConnection.h
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@ -1,14 +1,13 @@
#ifndef ASYNCDBCONNECTION_H
#define ASYNCDBCONNECTION_H
#include <QObject>
#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>
@ -16,10 +15,12 @@
/** \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 on that routine is called.
* 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 QObject {
Q_OBJECT
class ASyncDBConnection {
public:
enum class State {
NotConnected,
@ -39,20 +40,36 @@ public:
void setupConnection(const ConnectionConfig &config);
void closeConnection();
/** Sends command to the server.
/** \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.
*/
When the result is in on_result will be called directly within the thread.
If the command gives multiple results on_result will be called for each result.
*/
/** \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();
signals:
void onStateChanged(ASyncDBConnection::State state);
void onNotice(Pgsql::ErrorDetails notice);
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;
@ -60,7 +77,9 @@ private:
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);
@ -69,8 +88,4 @@ private:
void processNotice(const PGresult *result);
};
Q_DECLARE_METATYPE(ASyncDBConnection::State);
Q_DECLARE_METATYPE(Pgsql::ErrorDetails);
#endif // ASYNCDBCONNECTION_H