+/*
+ Copyright (C) 2012 Paul Davis
+
+ 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, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
#include <stdlib.h>
#include <string.h>
+#include <assert.h>
#include <locale.h>
+#include "pbd/compose.h"
+#include "pbd/debug.h"
+#include "pbd/error.h"
#include "pbd/locale_guard.h"
using namespace PBD;
-LocaleGuard::LocaleGuard (const char* str)
+/* Neither C nor C++ pick up a user's preferred locale choice without the
+ * application actively taking steps to make this happen.
+ *
+ * For C: setlocale (LC_ALL, "");
+ * For C++ (assuming that the C version was called):
+ * std::locale::global (std::locale (setlocale (LC_ALL, 0)));
+ *
+ * The application needs to make these calls, probably in main().
+ *
+ * Setting the C++ locale will change the C locale, but not the other way 'round.
+ * and some plugin may change either behind our back.
+ */
+
+LocaleGuard::LocaleGuard ()
+ : old_c_locale (0)
{
- old = setlocale (LC_NUMERIC, NULL);
-
- if (old) {
- old = strdup (old);
- if (strcmp (old, str)) {
- setlocale (LC_NUMERIC, str);
- }
- }
+ /* A LocaleGuard object ensures that the
+ * LC_NUMERIC/std::locale::numeric aspect of the C and C++ locales are
+ * set to "C" during its lifetime, so that printf/iostreams use a
+ * portable format for numeric output (i.e. 1234.5 is always 1234.5 and
+ * not sometimes 1234,5, as it would be in fr or de locales)
+ */
+
+ char const * const current_c_locale = setlocale (LC_NUMERIC, 0);
+
+ if (strcmp ("C", current_c_locale) != 0) {
+
+ old_c_locale = strdup (current_c_locale);
+
+ try {
+ /* set the C++ global/default locale to whatever we are using
+ * now, but with "C" numeric handling.
+ *
+ * this also sets the C locale, so no additional call to setlocale() is required.
+ */
+
+ std::locale::global (std::locale (old_cpp_locale, "C", std::locale::numeric));
+ pre_cpp_locale = std::locale();
+ DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: change C & C++ locale from '%1' => %2\n", old_cpp_locale.name(), pre_cpp_locale.name()));
+
+ } catch (...) {
+ /* Apple in particular have historically done a
+ * terrible job supporting setlocale and even more so
+ * with the C++ API. Using any locale other than "C" or
+ * "POSIX" will fail, and in the case of the C++ API,
+ * will throw an exception. In that case, just try to
+ * use setlocale() to reset *only* the numeric aspect
+ * of the current locale settings back to "C", which is
+ * likely to work everywhere.
+ */
+
+ setlocale (LC_NUMERIC, "C");
+ pre_cpp_locale = std::locale();
+ DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: C++ locale API failed, change just C locale from '%1' => 'C' (C++ locale is %2)\n", old_c_locale, pre_cpp_locale.name()));
+ }
+
+ }
}
LocaleGuard::~LocaleGuard ()
{
- setlocale (LC_NUMERIC, old);
+ char const * current_c_locale = setlocale (LC_NUMERIC, 0);
+ std::locale current_cpp_locale;
- if (old) {
- free ((char*)old);
- }
-}
+ if (current_cpp_locale != pre_cpp_locale) {
+ PBD::warning << string_compose ("LocaleGuard: someone (a plugin) changed the C++ locale from\n\t%1\nto\n\t%2\n, expect non-portable session files. Decimal OK ? %2",
+ old_cpp_locale.name(), current_cpp_locale.name(),
+ (std::use_facet<std::numpunct<char> >(std::locale()).decimal_point() == '.'))
+ << endmsg;
+
+ try {
+ /* this resets C & C++ locales */
+ std::locale::global (old_cpp_locale);
+ DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: restore C & C++ locale: '%1'\n", std::locale().name()));
+ } catch (...) {
+ /* see comments in the constructor regarding the
+ * exception.
+ *
+ * This should restore restore numeric handling back to
+ * the default (which may reflect user
+ * preferences). This probably can't fail, because
+ * old_c_locale was already in use during the
+ * constructor for this object.
+ *
+ * Still ... Apple ... locale support ... just sayin' ....
+ */
+ setlocale (LC_NUMERIC, old_c_locale);
+ DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: C++ locale API failed, restore C locale from %1 to\n'%2'\n(C++ is '%3')\n", current_c_locale, old_c_locale, std::locale().name()));
+ }
+
+ } else if (old_c_locale && (strcmp (current_c_locale, old_c_locale) != 0)) {
+
+ /* reset only the C locale */
+ setlocale (LC_NUMERIC, old_c_locale);
+ DEBUG_TRACE (DEBUG::Locale, string_compose ("LG: restore C locale from %1 to\n'%2'\n(C++ is '%3')\n", current_c_locale, old_c_locale, std::locale().name()));
+ }
+
+ free (const_cast<char*> (old_c_locale));
+}
projects / ardour.git / blobdiff