diff options
Diffstat (limited to 'lib/rpmatch.c')
| -rw-r--r-- | lib/rpmatch.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/lib/rpmatch.c b/lib/rpmatch.c new file mode 100644 index 0000000..01eab24 --- /dev/null +++ b/lib/rpmatch.c @@ -0,0 +1,176 @@ +/* Determine whether string value is affirmation or negative response + according to current locale's data. + + Copyright (C) 1996, 1998, 2000, 2002-2003, 2006-2022 Free Software + Foundation, Inc. + + 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 3 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, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +/* Specification. */ +#include <stdlib.h> + +#include <stdbool.h> +#include <stddef.h> + +#if ENABLE_NLS +# include <sys/types.h> +# include <limits.h> +# include <string.h> +# if HAVE_LANGINFO_YESEXPR +# include <langinfo.h> +# endif +# include <regex.h> +# include "gettext.h" +# define _(msgid) gettext (msgid) +# define N_(msgid) gettext_noop (msgid) + +# if HAVE_LANGINFO_YESEXPR +/* Return the localized regular expression pattern corresponding to + ENGLISH_PATTERN. NL_INDEX can be used with nl_langinfo. + The resulting string may only be used until the next nl_langinfo call. */ +static const char * +localized_pattern (const char *english_pattern, nl_item nl_index, + bool posixly_correct) +{ + const char *translated_pattern; + + /* We prefer to get the patterns from a PO file. It would be possible to + always use nl_langinfo (YESEXPR) instead of _("^[yY]"), and + nl_langinfo (NOEXPR) instead of _("^[nN]"), if we could assume that the + system's locale support is good. But this is not the case e.g. on Cygwin. + The localizations of gnulib.pot are of better quality in general. + Also, if we use locale info from non-free systems that don't have a + 'localedef' command, we deprive the users of the freedom to localize + this pattern for their preferred language. + But some programs, such as 'cp', 'mv', 'rm', 'find', 'xargs', are + specified by POSIX to use nl_langinfo (YESEXPR). We implement this + behaviour if POSIXLY_CORRECT is set, for the sake of these programs. */ + + /* If the user wants strict POSIX compliance, use nl_langinfo. */ + if (posixly_correct) + { + translated_pattern = nl_langinfo (nl_index); + /* Check against a broken system return value. */ + if (translated_pattern != NULL && translated_pattern[0] != '\0') + return translated_pattern; + } + + /* Look in the gnulib message catalog. */ + translated_pattern = _(english_pattern); + if (translated_pattern == english_pattern) + { + /* The gnulib message catalog provides no translation. + Try the system's message catalog. */ + translated_pattern = nl_langinfo (nl_index); + /* Check against a broken system return value. */ + if (translated_pattern != NULL && translated_pattern[0] != '\0') + return translated_pattern; + /* Fall back to English. */ + translated_pattern = english_pattern; + } + return translated_pattern; +} +# else +# define localized_pattern(english_pattern,nl_index,posixly_correct) \ + _(english_pattern) +# endif + +static int +try (const char *response, const char *pattern, char **lastp, regex_t *re) +{ + if (*lastp == NULL || strcmp (pattern, *lastp) != 0) + { + char *safe_pattern; + + /* The pattern has changed. */ + if (*lastp != NULL) + { + /* Free the old compiled pattern. */ + regfree (re); + free (*lastp); + *lastp = NULL; + } + /* Put the PATTERN into safe memory before calling regcomp. + (regcomp may call nl_langinfo, overwriting PATTERN's storage. */ + safe_pattern = strdup (pattern); + if (safe_pattern == NULL) + return -1; + /* Compile the pattern and cache it for future runs. */ + if (regcomp (re, safe_pattern, REG_EXTENDED) != 0) + { + free (safe_pattern); + return -1; + } + *lastp = safe_pattern; + } + + /* See if the regular expression matches RESPONSE. */ + return regexec (re, response, 0, NULL, 0) == 0; +} +#endif + + +int +rpmatch (const char *response) +{ +#if ENABLE_NLS + /* Match against one of the response patterns, compiling the pattern + first if necessary. */ + + /* We cache the response patterns and compiled regexps here. */ + static char *last_yesexpr, *last_noexpr; + static regex_t cached_yesre, cached_nore; + +# if HAVE_LANGINFO_YESEXPR + bool posixly_correct = (getenv ("POSIXLY_CORRECT") != NULL); +# endif + + const char *yesexpr, *noexpr; + int result; + + /* TRANSLATORS: A regular expression testing for an affirmative answer + (english: "yes"). Testing the first character may be sufficient. + Take care to consider upper and lower case. + To enquire the regular expression that your system uses for this + purpose, you can use the command + locale -k LC_MESSAGES | grep '^yesexpr=' */ + yesexpr = localized_pattern (N_("^[yY]"), YESEXPR, posixly_correct); + result = try (response, yesexpr, &last_yesexpr, &cached_yesre); + if (result < 0) + return -1; + if (result) + return 1; + + /* TRANSLATORS: A regular expression testing for a negative answer + (english: "no"). Testing the first character may be sufficient. + Take care to consider upper and lower case. + To enquire the regular expression that your system uses for this + purpose, you can use the command + locale -k LC_MESSAGES | grep '^noexpr=' */ + noexpr = localized_pattern (N_("^[nN]"), NOEXPR, posixly_correct); + result = try (response, noexpr, &last_noexpr, &cached_nore); + if (result < 0) + return -1; + if (result) + return 0; + + return -1; +#else + /* Test against "^[yY]" and "^[nN]", hardcoded to avoid requiring regex */ + return (*response == 'y' || *response == 'Y' ? 1 + : *response == 'n' || *response == 'N' ? 0 : -1); +#endif +} |