rework locale-guard for C and C++ locales

let's hope querying the C-locale is more lightweight than setting it
on windows.

diff --git a/libs/pbd/locale_guard.cc b/libs/pbd/locale_guard.cc
index 4ec64984b08abe05f8bef216389467485ddb663c..c0d351febf0214834406fb99e9d56c3965690c58 100644 (file)
--- a/libs/pbd/locale_guard.cc
+++ b/libs/pbd/locale_guard.cc
@@ -19,36 +19,62 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <assert.h>
 #include <locale.h>
 
 #include "pbd/locale_guard.h"
 
 using namespace PBD;
 
-// try to avoid calling setlocale() recursively.  this is not thread-safe.
-std::string PBD::LocaleGuard::current;
+/* The initial C++ locate is "C" regardless of the user's preferred locale.
+ * and affects std::sprintf() et al from <cstdio>
+ *
+ * the C locale from stlocale() matches the user's preferred locale
+ * and effects ::sprintf() et al from <stdio.h>
+ *
+ * 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 (const char* str)
-       : old(0)
+LocaleGuard::LocaleGuard (const char*)
+       : old_c (0)
 {
-       if (current != str) {
-               old = strdup (setlocale (LC_NUMERIC, NULL));
-               if (strcmp (old, str)) {
-                       if (setlocale (LC_NUMERIC, str)) {
-                               current = str;
-                       }
-               }
+       init ();
+}
+
+LocaleGuard::LocaleGuard ()
+       : old_c (0)
+{
+       init ();
+}
+
+void
+LocaleGuard::init ()
+{
+       char* actual = setlocale (LC_NUMERIC, NULL);
+       if (strcmp ("C", actual)) {
+               old_c = strdup (actual);
+               /* this changes both C++ and C locale */
+               std::locale::global (std::locale (std::locale::classic(), "C", std::locale::numeric));
        }
+       assert (old_cpp == std::locale::classic ());
 }
 
 LocaleGuard::~LocaleGuard ()
 {
-       if (old) {
-               if (setlocale (LC_NUMERIC, old)) {
-                       current = old;
-               }
+       char* actual = setlocale (LC_NUMERIC, NULL);
+       std::locale current;
 
-               free (old);
+       if (current != old_cpp) {
+               /* the C++ locale should always be "C", that's the default
+                * at application start, and ardour never changes it
+                * if it's not: some plugin meddled with it.
+                */
+               assert (old_cpp == std::locale::classic ());
+               std::locale::global (old_cpp);
        }
+       if (old_c && strcmp (old_c, actual)) {
+               setlocale (LC_NUMERIC, old_c);
+       }
+       free (old_c);
 }
-

diff --git a/libs/pbd/pbd/locale_guard.h b/libs/pbd/pbd/locale_guard.h
index dc82ab4483defab306ffafe2284969455565e8d4..3d37562cedf41925114b2df8fd3e225d012c87ce 100644 (file)
--- a/libs/pbd/pbd/locale_guard.h
+++ b/libs/pbd/pbd/locale_guard.h
@@ -22,20 +22,21 @@
 
 #include "pbd/libpbd_visibility.h"
 
-#include <string>
+#include <locale>
 
 namespace PBD {
 
-struct LIBPBD_API LocaleGuard {
-    LocaleGuard (const char*);
-    ~LocaleGuard ();
-
-       static std::string current;
-
-private:
-    char* old;
-};
-
+       struct LIBPBD_API LocaleGuard {
+               public:
+                       LocaleGuard ();
+                       LocaleGuard (const char*); // deprecated
+                       ~LocaleGuard ();
+
+               private:
+                       void init ();
+                       std::locale old_cpp;
+                       char* old_c;
+       };
 }
 
 #endif /* __pbd_locale_guard__ */