gettext.c

   1 /*
   2  * Copyright (c) 2010 Ævar Arnfjörð Bjarmason
   3  */
   4
   5 #include "cache.h"
   6 #include "exec-cmd.h"
   7 #include "gettext.h"
   8 #include "strbuf.h"
   9 #include "utf8.h"
  10 #include "config.h"
  11
  12 #ifndef NO_GETTEXT
  13 #       include <locale.h>
  14 #       include <libintl.h>
  15 #       ifdef HAVE_LIBCHARSET_H
  16 #               include <libcharset.h>
  17 #       else
  18 #               include <langinfo.h>
  19 #               define locale_charset() nl_langinfo(CODESET)
  20 #       endif
  21 #endif
  22
  23 static const char *charset;
  24
  25 /*
  26  * Guess the user's preferred languages from the value in LANGUAGE environment
  27  * variable and LC_MESSAGES locale category if NO_GETTEXT is not defined.
  28  *
  29  * The result can be a colon-separated list like "ko:ja:en".
  30  */
  31 const char *get_preferred_languages(void)
  32 {
  33         const char *retval;
  34
  35         retval = getenv("LANGUAGE");
  36         if (retval && *retval)
  37                 return retval;
  38
  39 #ifndef NO_GETTEXT
  40         retval = setlocale(LC_MESSAGES, NULL);
  41         if (retval && *retval &&
  42                 strcmp(retval, "C") &&
  43                 strcmp(retval, "POSIX"))
  44                 return retval;
  45 #endif
  46
  47         return NULL;
  48 }
  49
  50 int use_gettext_poison(void)
  51 {
  52         static int poison_requested = -1;
  53         if (poison_requested == -1) {
  54                 const char *v = getenv("GIT_TEST_GETTEXT_POISON");
  55                 poison_requested = v && strlen(v) ? 1 : 0;
  56         }
  57         return poison_requested;
  58 }
  59
  60 #ifndef NO_GETTEXT
  61 static int test_vsnprintf(const char *fmt, ...)
  62 {
  63         char buf[26];
  64         int ret;
  65         va_list ap;
  66         va_start(ap, fmt);
  67         ret = vsnprintf(buf, sizeof(buf), fmt, ap);
  68         va_end(ap);
  69         return ret;
  70 }
  71
  72 static void init_gettext_charset(const char *domain)
  73 {
  74         /*
  75            This trick arranges for messages to be emitted in the user's
  76            requested encoding, but avoids setting LC_CTYPE from the
  77            environment for the whole program.
  78
  79            This primarily done to avoid a bug in vsnprintf in the GNU C
  80            Library [1]. which triggered a "your vsnprintf is broken" error
  81            on Git's own repository when inspecting v0.99.6~1 under a UTF-8
  82            locale.
  83
  84            That commit contains a ISO-8859-1 encoded author name, which
  85            the locale aware vsnprintf(3) won't interpolate in the format
  86            argument, due to mismatch between the data encoding and the
  87            locale.
  88
  89            Even if it wasn't for that bug we wouldn't want to use LC_CTYPE at
  90            this point, because it'd require auditing all the code that uses C
  91            functions whose semantics are modified by LC_CTYPE.
  92
  93            But only setting LC_MESSAGES as we do creates a problem, since
  94            we declare the encoding of our PO files[2] the gettext
  95            implementation will try to recode it to the user's locale, but
  96            without LC_CTYPE it'll emit something like this on 'git init'
  97            under the Icelandic locale:
  98
  99                Bj? til t?ma Git lind ? /hlagh/.git/
 100
 101            Gettext knows about the encoding of our PO file, but we haven't
 102            told it about the user's encoding, so all the non-US-ASCII
 103            characters get encoded to question marks.
 104
 105            But we're in luck! We can set LC_CTYPE from the environment
 106            only while we call nl_langinfo and
 107            bind_textdomain_codeset. That suffices to tell gettext what
 108            encoding it should emit in, so it'll now say:
 109
 110                Bjó til tóma Git lind í /hlagh/.git/
 111
 112            And the equivalent ISO-8859-1 string will be emitted under a
 113            ISO-8859-1 locale.
 114
 115            With this change way we get the advantages of setting LC_CTYPE
 116            (talk to the user in his language/encoding), without the major
 117            drawbacks (changed semantics for C functions we rely on).
 118
 119            However foreign functions using other message catalogs that
 120            aren't using our neat trick will still have a problem, e.g. if
 121            we have to call perror(3):
 122
 123            #include <stdio.h>
 124            #include <locale.h>
 125            #include <errno.h>
 126
 127            int main(void)
 128            {
 129                    setlocale(LC_MESSAGES, "");
 130                    setlocale(LC_CTYPE, "C");
 131                    errno = ENODEV;
 132                    perror("test");
 133                    return 0;
 134            }
 135
 136            Running that will give you a message with question marks:
 137
 138            $ LANGUAGE= LANG=de_DE.utf8 ./test
 139            test: Kein passendes Ger?t gefunden
 140
 141            The vsnprintf bug has been fixed since glibc 2.17.
 142
 143            Then we could simply set LC_CTYPE from the environment, which would
 144            make things like the external perror(3) messages work.
 145
 146            See t/t0203-gettext-setlocale-sanity.sh's "gettext.c" tests for
 147            regression tests.
 148
 149            1. http://sourceware.org/bugzilla/show_bug.cgi?id=6530
 150            2. E.g. "Content-Type: text/plain; charset=UTF-8\n" in po/is.po
 151         */
 152         setlocale(LC_CTYPE, "");
 153         charset = locale_charset();
 154         bind_textdomain_codeset(domain, charset);
 155         /* the string is taken from v0.99.6~1 */
 156         if (test_vsnprintf("%.*s", 13, "David_K\345gedal") < 0)
 157                 setlocale(LC_CTYPE, "C");
 158 }
 159
 160 void git_setup_gettext(void)
 161 {
 162         const char *podir = getenv(GIT_TEXT_DOMAIN_DIR_ENVIRONMENT);
 163         char *p = NULL;
 164
 165         if (!podir)
 166                 podir = p = system_path(GIT_LOCALE_PATH);
 167
 168         use_gettext_poison(); /* getenv() reentrancy paranoia */
 169
 170         if (!is_directory(podir)) {
 171                 free(p);
 172                 return;
 173         }
 174
 175         bindtextdomain("git", podir);
 176         setlocale(LC_MESSAGES, "");
 177         setlocale(LC_TIME, "");
 178         init_gettext_charset("git");
 179         textdomain("git");
 180
 181         free(p);
 182 }
 183
 184 /* return the number of columns of string 's' in current locale */
 185 int gettext_width(const char *s)
 186 {
 187         static int is_utf8 = -1;
 188         if (is_utf8 == -1)
 189                 is_utf8 = is_utf8_locale();
 190
 191         return is_utf8 ? utf8_strwidth(s) : strlen(s);
 192 }
 193 #endif
 194
 195 int is_utf8_locale(void)
 196 {
 197 #ifdef NO_GETTEXT
 198         if (!charset) {
 199                 const char *env = getenv("LC_ALL");
 200                 if (!env || !*env)
 201                         env = getenv("LC_CTYPE");
 202                 if (!env || !*env)
 203                         env = getenv("LANG");
 204                 if (!env)
 205                         env = "";
 206                 if (strchr(env, '.'))
 207                         env = strchr(env, '.') + 1;
 208                 charset = xstrdup(env);
 209         }
 210 #endif
 211         return is_encoding_utf8(charset);
 212 }