X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=libs%2Fpbd%2Flocale_guard.cc;h=93ff11e2935d808c657bb42aba805f8c621c30a2;hb=1ce58ad90aab58bca10af9c448b8e186ac532480;hp=44b9fc2b649fba798be148b6cdab1023430e18b1;hpb=58a027b7a2eec138a833922dbf1e5e5918d58e78;p=ardour.git

diff --git a/libs/pbd/locale_guard.cc b/libs/pbd/locale_guard.cc
index 44b9fc2b64..93ff11e293 100644
--- a/libs/pbd/locale_guard.cc
+++ b/libs/pbd/locale_guard.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012 Paul Davis 
+    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
@@ -19,30 +19,113 @@
 
 #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 (const_cast<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));
+}