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Make citext's equality and hashing functions collation-insensitive.

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This is an ugly hack to get around the fact that significant parts of the
core backend assume they don't need to worry about passing collation to
equality and hashing functions.  That's true for the core string datatypes,
but citext should ideally have equality behavior that depends on the
specified collation's LC_CTYPE.  However, there's no chance of fixing the
core before 9.2, so we'll have to live with this compromise arrangement for
now.  Per bug #6053 from Regina Obe.

The code changes in this commit should be reverted in full once the core
code is up to speed, but be careful about reverting the docs changes:
I fixed a number of obsolete statements while at it.
This commit is contained in:
Tom Lane
2011-06-08 15:24:27 -04:00
parent 1bcdd66315
commit 3ebc061c18
2 changed files with 52 additions and 21 deletions
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23
contrib/citext/citext.c
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@ -4,6 +4,7 @@
#include "postgres.h"
#include "access/hash.h"
#include "catalog/pg_collation.h"
#include "fmgr.h"
#include "utils/builtins.h"
#include "utils/formatting.h"
@ -48,8 +49,16 @@ citextcmp(text *left, text *right, Oid collid)
*rcstr;
int32 result;
lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), collid);
rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), collid);
/*
* We must do our str_tolower calls with DEFAULT_COLLATION_OID, not the
* input collation as you might expect. This is so that the behavior of
* citext's equality and hashing functions is not collation-dependent. We
* should change this once the core infrastructure is able to cope with
* collation-dependent equality and hashing functions.
*/
lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
result = varstr_cmp(lcstr, strlen(lcstr),
rcstr, strlen(rcstr),
@ -93,7 +102,7 @@ citext_hash(PG_FUNCTION_ARGS)
char *str;
Datum result;
str = str_tolower(VARDATA_ANY(txt), VARSIZE_ANY_EXHDR(txt), PG_GET_COLLATION());
str = str_tolower(VARDATA_ANY(txt), VARSIZE_ANY_EXHDR(txt), DEFAULT_COLLATION_OID);
result = hash_any((unsigned char *) str, strlen(str));
pfree(str);
@ -122,8 +131,8 @@ citext_eq(PG_FUNCTION_ARGS)
/* We can't compare lengths in advance of downcasing ... */
lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), PG_GET_COLLATION());
rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), PG_GET_COLLATION());
lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
/*
* Since we only care about equality or not-equality, we can avoid all the
@ -152,8 +161,8 @@ citext_ne(PG_FUNCTION_ARGS)
/* We can't compare lengths in advance of downcasing ... */
lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), PG_GET_COLLATION());
rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), PG_GET_COLLATION());
lcstr = str_tolower(VARDATA_ANY(left), VARSIZE_ANY_EXHDR(left), DEFAULT_COLLATION_OID);
rcstr = str_tolower(VARDATA_ANY(right), VARSIZE_ANY_EXHDR(right), DEFAULT_COLLATION_OID);
/*
* Since we only care about equality or not-equality, we can avoid all the