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Control collation behavior with a method table.

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Previously, behavior branched based on the provider. A method table is
less error-prone and more flexible.

The ctype behavior will be addressed in an upcoming commit.

Reviewed-by: Andreas Karlsson
Discussion: https://postgr.es/m/2830211e1b6e6a2e26d845780b03e125281ea17b.camel%40j-davis.com
This commit is contained in:
Jeff Davis
2025-01-08 14:26:33 -08:00
parent 4f5cef2607
commit a2f17f004d
4 changed files with 180 additions and 176 deletions
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53
src/backend/utils/adt/pg_locale_libc.c
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@@ -50,10 +50,10 @@ extern size_t strtitle_libc(char *dst, size_t dstsize, const char *src,
extern size_t strupper_libc(char *dst, size_t dstsize, const char *src,
ssize_t srclen, pg_locale_t locale);
extern int strncoll_libc(const char *arg1, ssize_t len1,
static int strncoll_libc(const char *arg1, ssize_t len1,
const char *arg2, ssize_t len2,
pg_locale_t locale);
extern size_t strnxfrm_libc(char *dest, size_t destsize,
static size_t strnxfrm_libc(char *dest, size_t destsize,
const char *src, ssize_t srclen,
pg_locale_t locale);
extern char *get_collation_actual_version_libc(const char *collcollate);
@@ -86,6 +86,40 @@ static size_t strupper_libc_mb(char *dest, size_t destsize,
const char *src, ssize_t srclen,
pg_locale_t locale);
static const struct collate_methods collate_methods_libc = {
.strncoll = strncoll_libc,
.strnxfrm = strnxfrm_libc,
.strnxfrm_prefix = NULL,
/*
* Unfortunately, it seems that strxfrm() for non-C collations is broken
* on many common platforms; testing of multiple versions of glibc reveals
* that, for many locales, strcoll() and strxfrm() do not return
* consistent results. While no other libc other than Cygwin has so far
* been shown to have a problem, we take the conservative course of action
* for right now and disable this categorically. (Users who are certain
* this isn't a problem on their system can define TRUST_STRXFRM.)
*/
#ifdef TRUST_STRXFRM
.strxfrm_is_safe = true,
#else
.strxfrm_is_safe = false,
#endif
};
#ifdef WIN32
static const struct collate_methods collate_methods_libc_win32_utf8 = {
.strncoll = strncoll_libc_win32_utf8,
.strnxfrm = strnxfrm_libc,
.strnxfrm_prefix = NULL,
#ifdef TRUST_STRXFRM
.strxfrm_is_safe = true,
#else
.strxfrm_is_safe = false,
#endif
};
#endif
size_t
strlower_libc(char *dst, size_t dstsize, const char *src,
ssize_t srclen, pg_locale_t locale)
@@ -439,6 +473,15 @@ create_pg_locale_libc(Oid collid, MemoryContext context)
result->ctype_is_c = (strcmp(ctype, "C") == 0) ||
(strcmp(ctype, "POSIX") == 0);
result->info.lt = loc;
if (!result->collate_is_c)
{
#ifdef WIN32
if (GetDatabaseEncoding() == PG_UTF8)
result->collate = &collate_methods_libc_win32_utf8;
else
#endif
result->collate = &collate_methods_libc;
}
return result;
}
@@ -536,12 +579,6 @@ strncoll_libc(const char *arg1, ssize_t len1, const char *arg2, ssize_t len2,
Assert(locale->provider == COLLPROVIDER_LIBC);
#ifdef WIN32
/* check for this case before doing the work for nul-termination */
if (GetDatabaseEncoding() == PG_UTF8)
return strncoll_libc_win32_utf8(arg1, len1, arg2, len2, locale);
#endif /* WIN32 */
if (bufsize1 + bufsize2 > TEXTBUFLEN)
buf = palloc(bufsize1 + bufsize2);