wxWidgets Singleton Example

app.cpp

/*
 * Copyright (C) 2023 - 2024 Vadym Hrynchyshyn <[email protected]>
 */

#include "app.h"
#include "utils.h"
#include "wusbip.h"

#include <libusbip/src/file_ver.h>

using namespace usbip;

App::App()
{
        Bind(wxEVT_END_SESSION, &App::on_end_session, this);
}

bool App::OnInit()
{
	/* wxString app_instance = */
	auto app_instance = wxString::Format(wxT("my_app_instance_%s"), 			
		wxGetUserId().c_str());

	// 1. https://docs.wxwidgets.org/3.0/classwx_single_instance_checker.html#
        m_checker = new wxSingleInstanceChecker(app_instance);
        if (m_checker->IsAnotherRunning()) {
            wxLogError(wxT("Another instance is already running."));
            return false; // Don't start a new instance
        }

        if (wxApp::OnInit()) {
                set_names();
        } else {
                return false;
        }

        wxString err;

        if (auto read = init(err) ? vhci::open() : Handle()) {
                if (auto &frame = *new MainFrame(std::move(read)); frame.start_in_tray()) {
                        frame.iconize_to_tray();
                } else {
                        frame.Show();
                }
                return true;
        }

        if (err.empty()) {
                err = GetLastErrorMsg();
        }

        wxSafeShowMessage(_("Fatal error"), err);
        return false;
}

void App::set_names()
{
        auto &v = win::get_file_version();


        SetAppName(wx_string(v.GetProductName()));
        SetVendorName(wx_string(v.GetCompanyName()));
}

/*
 * wxEVT_CLOSE_WINDOW will not be sent to MainFrame, but m_read_thread must be joined.
 * @see MainFrame::on_close
 */
void App::on_end_session(_In_ wxCloseEvent&)
{
        if (auto wnd = GetMainTopWindow()) {
                wnd->Close(true);
        }
}

bool App::OnExit()
{
	delete m_checker;
	return false; // 0
} 

wxIMPLEMENT_APP(App);

app.h

/*
 * Copyright (C) 2023 - 2024 Vadym Hrynchyshyn <[email protected]>
 */

#pragma once

#include <wx/app.h>
#include <wx/singleinst.h>
#include <wx/log.h>


class App : public wxApp
{
public:
        App();
        bool OnInit() override;
	// 1. https://docs.wxwidgets.org/3.0/classwx_single_instance_checker.html#
        bool OnExit() override;

private:
        void set_names();
        void on_end_session(_In_ wxCloseEvent &event);
	// 1. https://docs.wxwidgets.org/3.0/classwx_single_instance_checker.html#
	wxSingleInstanceChecker *m_checker;
};

wxDECLARE_APP(App);