gettext.c

   1 /*
   2  * Copyright (c) 2010 Ævar Arnfjörð Bjarmason
   3  */
   4
   5 #include "git-compat-util.h"
   6 #include "gettext.h"
   7 #include "strbuf.h"
   8 #include "utf8.h"
   9
  10 #ifndef NO_GETTEXT
  11 #       include <locale.h>
  12 #       include <libintl.h>
  13 #       ifdef HAVE_LIBCHARSET_H
  14 #               include <libcharset.h>
  15 #       else
  16 #               include <langinfo.h>
  17 #               define locale_charset() nl_langinfo(CODESET)
  18 #       endif
  19 #endif
  20
  21 static const char *charset;
  22
  23 /*
  24  * Guess the user's preferred languages from the value in LANGUAGE environment
  25  * variable and LC_MESSAGES locale category if NO_GETTEXT is not defined.
  26  *
  27  * The result can be a colon-separated list like "ko:ja:en".
  28  */
  29 const char *get_preferred_languages(void)
  30 {
  31         const char *retval;
  32
  33         retval = getenv("LANGUAGE");
  34         if (retval && *retval)
  35                 return retval;
  36
  37 #ifndef NO_GETTEXT
  38         retval = setlocale(LC_MESSAGES, NULL);
  39         if (retval && *retval &&
  40                 strcmp(retval, "C") &&
  41                 strcmp(retval, "POSIX"))
  42                 return retval;
  43 #endif
  44
  45         return NULL;
  46 }
  47
  48 #ifdef GETTEXT_POISON
  49 int use_gettext_poison(void)
  50 {
  51         static int poison_requested = -1;
  52         if (poison_requested == -1)
  53                 poison_requested = getenv("GIT_GETTEXT_POISON") ? 1 : 0;
  54         return poison_requested;
  55 }
  56 #endif
  57
  58 #ifndef NO_GETTEXT
  59 static int test_vsnprintf(const char *fmt, ...)
  60 {
  61         char buf[26];
  62         int ret;
  63         va_list ap;
  64         va_start(ap, fmt);
  65         ret = vsnprintf(buf, sizeof(buf), fmt, ap);
  66         va_end(ap);
  67         return ret;
  68 }
  69
  70 static void init_gettext_charset(const char *domain)
  71 {
  72         /*
  73            This trick arranges for messages to be emitted in the user's
  74            requested encoding, but avoids setting LC_CTYPE from the
  75            environment for the whole program.
  76
  77            This primarily done to avoid a bug in vsnprintf in the GNU C
  78            Library [1]. which triggered a "your vsnprintf is broken" error
  79            on Git's own repository when inspecting v0.99.6~1 under a UTF-8
  80            locale.
  81
  82            That commit contains a ISO-8859-1 encoded author name, which
  83            the locale aware vsnprintf(3) won't interpolate in the format
  84            argument, due to mismatch between the data encoding and the
  85            locale.
  86
  87            Even if it wasn't for that bug we wouldn't want to use LC_CTYPE at
  88            this point, because it'd require auditing all the code that uses C
  89            functions whose semantics are modified by LC_CTYPE.
  90
  91            But only setting LC_MESSAGES as we do creates a problem, since
  92            we declare the encoding of our PO files[2] the gettext
  93            implementation will try to recode it to the user's locale, but
  94            without LC_CTYPE it'll emit something like this on 'git init'
  95            under the Icelandic locale:
  96
  97                Bj? til t?ma Git lind ? /hlagh/.git/
  98
  99            Gettext knows about the encoding of our PO file, but we haven't
 100            told it about the user's encoding, so all the non-US-ASCII
 101            characters get encoded to question marks.
 102
 103            But we're in luck! We can set LC_CTYPE from the environment
 104            only while we call nl_langinfo and
 105            bind_textdomain_codeset. That suffices to tell gettext what
 106            encoding it should emit in, so it'll now say:
 107
 108                Bjó til tóma Git lind í /hlagh/.git/
 109
 110            And the equivalent ISO-8859-1 string will be emitted under a
 111            ISO-8859-1 locale.
 112
 113            With this change way we get the advantages of setting LC_CTYPE
 114            (talk to the user in his language/encoding), without the major
 115            drawbacks (changed semantics for C functions we rely on).
 116
 117            However foreign functions using other message catalogs that
 118            aren't using our neat trick will still have a problem, e.g. if
 119            we have to call perror(3):
 120
 121            #include <stdio.h>
 122            #include <locale.h>
 123            #include <errno.h>
 124
 125            int main(void)
 126            {
 127                    setlocale(LC_MESSAGES, "");
 128                    setlocale(LC_CTYPE, "C");
 129                    errno = ENODEV;
 130                    perror("test");
 131                    return 0;
 132            }
 133
 134            Running that will give you a message with question marks:
 135
 136            $ LANGUAGE= LANG=de_DE.utf8 ./test
 137            test: Kein passendes Ger?t gefunden
 138
 139            The vsnprintf bug has been fixed since glibc 2.17.
 140
 141            Then we could simply set LC_CTYPE from the environment, which would
 142            make things like the external perror(3) messages work.
 143
 144            See t/t0203-gettext-setlocale-sanity.sh's "gettext.c" tests for
 145            regression tests.
 146
 147            1. http://sourceware.org/bugzilla/show_bug.cgi?id=6530
 148            2. E.g. "Content-Type: text/plain; charset=UTF-8\n" in po/is.po
 149         */
 150         setlocale(LC_CTYPE, "");
 151         charset = locale_charset();
 152         bind_textdomain_codeset(domain, charset);
 153         /* the string is taken from v0.99.6~1 */
 154         if (test_vsnprintf("%.*s", 13, "David_K\345gedal") < 0)
 155                 setlocale(LC_CTYPE, "C");
 156 }
 157
 158 void git_setup_gettext(void)
 159 {
 160         const char *podir = getenv("GIT_TEXTDOMAINDIR");
 161
 162         if (!podir)
 163                 podir = GIT_LOCALE_PATH;
 164         bindtextdomain("git", podir);
 165         setlocale(LC_MESSAGES, "");
 166         setlocale(LC_TIME, "");
 167         init_gettext_charset("git");
 168         textdomain("git");
 169 }
 170
 171 /* return the number of columns of string 's' in current locale */
 172 int gettext_width(const char *s)
 173 {
 174         static int is_utf8 = -1;
 175         if (is_utf8 == -1)
 176                 is_utf8 = is_utf8_locale();
 177
 178         return is_utf8 ? utf8_strwidth(s) : strlen(s);
 179 }
 180 #endif
 181
 182 int is_utf8_locale(void)
 183 {
 184 #ifdef NO_GETTEXT
 185         if (!charset) {
 186                 const char *env = getenv("LC_ALL");
 187                 if (!env || !*env)
 188                         env = getenv("LC_CTYPE");
 189                 if (!env || !*env)
 190                         env = getenv("LANG");
 191                 if (!env)
 192                         env = "";
 193                 if (strchr(env, '.'))
 194                         env = strchr(env, '.') + 1;
 195                 charset = xstrdup(env);
 196         }
 197 #endif
 198         return is_encoding_utf8(charset);
 199 }