ltree: fix case-insensitive matching.

Previously, ltree_prefix_eq_ci() used lowercasing with the default
collation; while ltree_crc32_sz() used tolower() directly. These were
equivalent only if the default collation provider was libc and the
encoding was single-byte.

Change both to use casefolding with the default collation.

Backpatch through 18, where the casefolding APIs were introduced. The
bug exists in earlier versions, but would require some adaptation.

A REINDEX is required for ltree indexes where the database default
collation is not libc.

Reviewed-by: Chao Li <[email protected]>
Reviewed-by: Peter Eisentraut <[email protected]>
Backpatch-through: 18
Discussion: https://postgr.es/m/450ceb6260cad30d7afdf155d991a9caafee7c0d[email protected]
Discussion: https://postgr.es/m/01fc00fd66f641b9693d4f9f1af0ccf44cbdfbdf[email protected]

diff --git a/contrib/ltree/crc32.c b/contrib/ltree/crc32.c
index 134f46a805e569a0ed991aad4460a9577429375c..3918d4a0ec251a1196ced515a3bb5a1bb4e91e34 100644 (file)
--- a/contrib/ltree/crc32.c
+++ b/contrib/ltree/crc32.c
@@ -10,31 +10,61 @@
 #include "postgres.h"
 #include "ltree.h"
 
+#include "crc32.h"
+#include "utils/pg_crc.h"
 #ifdef LOWER_NODE
-#include <ctype.h>
-#define TOLOWER(x) tolower((unsigned char) (x))
-#else
-#define TOLOWER(x) (x)
+#include "utils/pg_locale.h"
 #endif
 
-#include "crc32.h"
-#include "utils/pg_crc.h"
+#ifdef LOWER_NODE
 
 unsigned int
 ltree_crc32_sz(const char *buf, int size)
 {
    pg_crc32    crc;
    const char *p = buf;
+   static pg_locale_t locale = NULL;
+
+   if (!locale)
+       locale = pg_database_locale();
 
    INIT_TRADITIONAL_CRC32(crc);
    while (size > 0)
    {
-       char        c = (char) TOLOWER(*p);
+       char        foldstr[UNICODE_CASEMAP_BUFSZ];
+       int         srclen = pg_mblen(p);
+       size_t      foldlen;
+
+       /* fold one codepoint at a time */
+       foldlen = pg_strfold(foldstr, UNICODE_CASEMAP_BUFSZ, p, srclen,
+                            locale);
+
+       COMP_TRADITIONAL_CRC32(crc, foldstr, foldlen);
+
+       size -= srclen;
+       p += srclen;
+   }
+   FIN_TRADITIONAL_CRC32(crc);
+   return (unsigned int) crc;
+}
+
+#else
 
-       COMP_TRADITIONAL_CRC32(crc, &c, 1);
+unsigned int
+ltree_crc32_sz(const char *buf, int size)
+{
+   pg_crc32    crc;
+   const char *p = buf;
+
+   INIT_TRADITIONAL_CRC32(crc);
+   while (size > 0)
+   {
+       COMP_TRADITIONAL_CRC32(crc, p, 1);
        size--;
        p++;
    }
    FIN_TRADITIONAL_CRC32(crc);
    return (unsigned int) crc;
 }
+
+#endif                         /* !LOWER_NODE */

diff --git a/contrib/ltree/lquery_op.c b/contrib/ltree/lquery_op.c
index 0b39d64a83973f00aa88ef6be1c7e27311f6a73e..a28ddbf40de34224213b7fab73ff899ca1fd05da 100644 (file)
--- a/contrib/ltree/lquery_op.c
+++ b/contrib/ltree/lquery_op.c
@@ -93,11 +93,44 @@ ltree_prefix_eq(const char *a, size_t a_sz, const char *b, size_t b_sz)
 bool
 ltree_prefix_eq_ci(const char *a, size_t a_sz, const char *b, size_t b_sz)
 {
-   char       *al = str_tolower(a, a_sz, DEFAULT_COLLATION_OID);
-   char       *bl = str_tolower(b, b_sz, DEFAULT_COLLATION_OID);
+   static pg_locale_t locale = NULL;
+   size_t      al_sz = a_sz + 1;
+   size_t      al_len;
+   char       *al = palloc(al_sz);
+   size_t      bl_sz = b_sz + 1;
+   size_t      bl_len;
+   char       *bl = palloc(bl_sz);
    bool        res;
 
-   res = (strncmp(al, bl, a_sz) == 0);
+   if (!locale)
+       locale = pg_database_locale();
+
+   /* casefold both a and b */
+
+   al_len = pg_strfold(al, al_sz, a, a_sz, locale);
+   if (al_len + 1 > al_sz)
+   {
+       /* grow buffer if needed and retry */
+       al_sz = al_len + 1;
+       al = repalloc(al, al_sz);
+       al_len = pg_strfold(al, al_sz, a, a_sz, locale);
+       Assert(al_len + 1 <= al_sz);
+   }
+
+   bl_len = pg_strfold(bl, bl_sz, b, b_sz, locale);
+   if (bl_len + 1 > bl_sz)
+   {
+       /* grow buffer if needed and retry */
+       bl_sz = bl_len + 1;
+       bl = repalloc(bl, bl_sz);
+       bl_len = pg_strfold(bl, bl_sz, b, b_sz, locale);
+       Assert(bl_len + 1 <= bl_sz);
+   }
+
+   if (al_len > bl_len)
+       res = false;
+   else
+       res = (strncmp(al, bl, al_len) == 0);
 
    pfree(al);
    pfree(bl);