kicad/common/locale_io.cpp

/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 1992-2021 KiCad Developers, see AUTHORS.txt for contributors.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */

#include <locale_io.h>
#include <wx/intl.h>
#include <clocale>

// When reading/writing files, we need to switch to setlocale( LC_NUMERIC, "C" ).
// Works fine to read/write files with floating point numbers.
// We can call setlocale( LC_NUMERIC, "C" ) or wxLocale( "C", "C", "C", false )
// wxWidgets discourage a direct call to setlocale
// However, for us, calling wxLocale( "C", "C", "C", false ) has a unwanted effect:
// The I18N translations are no longer active, because the English dictionary is selected.
// To read files, this is not a major issues, but the result can differ
// from using setlocale(xx, "C").
// Previously, we used only setlocale( LC_NUMERIC, "C" )
//
// Known issues are
// on MSW
//    using setlocale( LC_NUMERIC, "C" ) generates an alert message in debug mode,
//    and this message ("Decimal separator mismatch") must be disabled.
//    But calling wxLocale( "C", "C", "C", false ) works fine
// On unix:
//    calling wxLocale( "C", "C", "C", false ) breaks env vars containing non ASCII7 chars.
//    these env vars return a empty string from wxGetEnv() in many cases, and if such a
//    var must be read after calling wxLocale( "C", "C", "C", false ), it looks like empty
//
// So use wxLocale on Windows and setlocale on unix


// set USE_WXLOCALE 0 to use setlocale, 1 to use wxLocale:
#if defined( _WIN32 )
#define USE_WXLOCALE 1
#else
#define USE_WXLOCALE 0
#endif

// On Windows, when using setlocale, a wx alert is generated
// in some cases (reading a bitmap for instance)
// So we disable alerts during the time a file is read or written
#if !USE_WXLOCALE
#if defined( _WIN32 ) && defined( DEBUG )
// a wxAssertHandler_t function to filter wxWidgets alert messages when reading/writing a file
// when switching the locale to LC_NUMERIC, "C"
// It is used in class LOCALE_IO to hide a useless (in kicad) wxWidgets alert message
void KiAssertFilter( const wxString &file, int line,
                     const wxString &func, const wxString &cond,
                     const wxString &msg)
{
    if( !msg.Contains( "Decimal separator mismatch" ) )
        wxTheApp->OnAssertFailure( file.c_str(), line, func.c_str(), cond.c_str(), msg.c_str() );
}
#endif
#endif

std::atomic<unsigned int> LOCALE_IO::m_c_count( 0 );

LOCALE_IO::LOCALE_IO() : m_wxLocale( nullptr )
{
    // use thread safe, atomic operation
    if( m_c_count++ == 0 )
    {
#if USE_WXLOCALE
        #define C_LANG "C"
        m_wxLocale = new wxLocale( C_LANG, C_LANG, C_LANG, false );
#else
        // Store the user locale name, to restore this locale later, in dtor
        m_user_locale = setlocale( LC_NUMERIC, nullptr );
#if defined( _WIN32 ) && defined( DEBUG )
        // Disable wxWidgets alerts
        wxSetAssertHandler( KiAssertFilter );
#endif
        // Switch the locale to C locale, to read/write files with fp numbers
        setlocale( LC_NUMERIC, "C" );
#endif
    }
}


LOCALE_IO::~LOCALE_IO()
{
    // use thread safe, atomic operation
    if( --m_c_count == 0 )
    {
        // revert to the user locale
#if USE_WXLOCALE
        delete m_wxLocale;      // Deleting m_wxLocale restored previous locale
        m_wxLocale = nullptr;
#else
        setlocale( LC_NUMERIC, m_user_locale.c_str() );
#if defined( _WIN32 ) && defined( DEBUG )
        // Enable wxWidgets alerts
        wxSetDefaultAssertHandler();
#endif
#endif
    }
}