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Eliminate some no-longer-needed workarounds for palloc's old behavior

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of rejecting palloc(0).  Also, tweak like_selectivity() to avoid assuming
the presented pattern is nonempty; although that assumption is valid,
it doesn't really help much, and the new coding is more correct anyway
since it properly handles redundant wildcards.  In combination these
changes should eliminate a Coverity warning noted by Martijn.
This commit is contained in:
Tom Lane 2006-04-20 17:50:18 +00:00
parent ea6d54ee06
commit efe222268f
1 changed files with 21 additions and 37 deletions
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58
src/backend/utils/adt/selfuncs.c
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@ -15,7 +15,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.198 2006/03/05 15:58:44 momjian Exp $ * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.199 2006/04/20 17:50:18 tgl Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -3736,14 +3736,8 @@ like_fixed_prefix(Const *patt_const, bool case_insensitive,
bytea *bstr = DatumGetByteaP(patt_const->constvalue); bytea *bstr = DatumGetByteaP(patt_const->constvalue);
pattlen = VARSIZE(bstr) - VARHDRSZ; pattlen = VARSIZE(bstr) - VARHDRSZ;
if (pattlen > 0) patt = (char *) palloc(pattlen);
{ memcpy(patt, VARDATA(bstr), pattlen);
patt = (char *) palloc(pattlen);
memcpy(patt, VARDATA(bstr), pattlen);
}
else
patt = NULL;
if ((Pointer) bstr != DatumGetPointer(patt_const->constvalue)) if ((Pointer) bstr != DatumGetPointer(patt_const->constvalue))
pfree(bstr); pfree(bstr);
} }
@ -3761,7 +3755,7 @@ like_fixed_prefix(Const *patt_const, bool case_insensitive,
if (patt[pos] == '\\') if (patt[pos] == '\\')
{ {
pos++; pos++;
if (patt[pos] == '\0' && typeid != BYTEAOID) if (pos >= pattlen)
break; break;
} }
@ -3794,8 +3788,7 @@ like_fixed_prefix(Const *patt_const, bool case_insensitive,
*rest_const = string_to_bytea_const(rest, pattlen - pos); *rest_const = string_to_bytea_const(rest, pattlen - pos);
} }
if (patt != NULL) pfree(patt);
pfree(patt);
pfree(match); pfree(match);
/* in LIKE, an empty pattern is an exact match! */ /* in LIKE, an empty pattern is an exact match! */
@ -4101,7 +4094,6 @@ like_selectivity(Const *patt_const, bool case_insensitive)
{ {
Selectivity sel = 1.0; Selectivity sel = 1.0;
int pos; int pos;
int start;
Oid typeid = patt_const->consttype; Oid typeid = patt_const->consttype;
char *patt; char *patt;
int pattlen; int pattlen;
@ -4124,23 +4116,20 @@ like_selectivity(Const *patt_const, bool case_insensitive)
bytea *bstr = DatumGetByteaP(patt_const->constvalue); bytea *bstr = DatumGetByteaP(patt_const->constvalue);
pattlen = VARSIZE(bstr) - VARHDRSZ; pattlen = VARSIZE(bstr) - VARHDRSZ;
if (pattlen > 0) patt = (char *) palloc(pattlen);
{ memcpy(patt, VARDATA(bstr), pattlen);
patt = (char *) palloc(pattlen);
memcpy(patt, VARDATA(bstr), pattlen);
}
else
patt = NULL;
if ((Pointer) bstr != DatumGetPointer(patt_const->constvalue)) if ((Pointer) bstr != DatumGetPointer(patt_const->constvalue))
pfree(bstr); pfree(bstr);
} }
/* patt should never be NULL in practice */
Assert(patt != NULL);
/* Skip any leading %; it's already factored into initial sel */ /* Skip any leading wildcard; it's already factored into initial sel */
start = (*patt == '%') ? 1 : 0; for (pos = 0; pos < pattlen; pos++)
for (pos = start; pos < pattlen; pos++) {
if (patt[pos] != '%' && patt[pos] != '_')
break;
}
for (; pos < pattlen; pos++)
{ {
/* % and _ are wildcard characters in LIKE */ /* % and _ are wildcard characters in LIKE */
if (patt[pos] == '%') if (patt[pos] == '%')
@ -4151,7 +4140,7 @@ like_selectivity(Const *patt_const, bool case_insensitive)
{ {
/* Backslash quotes the next character */ /* Backslash quotes the next character */
pos++; pos++;
if (patt[pos] == '\0' && typeid != BYTEAOID) if (pos >= pattlen)
break; break;
sel *= FIXED_CHAR_SEL; sel *= FIXED_CHAR_SEL;
} }
@ -4161,6 +4150,8 @@ like_selectivity(Const *patt_const, bool case_insensitive)
/* Could get sel > 1 if multiple wildcards */ /* Could get sel > 1 if multiple wildcards */
if (sel > 1.0) if (sel > 1.0)
sel = 1.0; sel = 1.0;
pfree(patt);
return sel; return sel;
} }
@ -4366,14 +4357,8 @@ make_greater_string(const Const *str_const)
bytea *bstr = DatumGetByteaP(str_const->constvalue); bytea *bstr = DatumGetByteaP(str_const->constvalue);
len = VARSIZE(bstr) - VARHDRSZ; len = VARSIZE(bstr) - VARHDRSZ;
if (len > 0) workstr = (char *) palloc(len);
{ memcpy(workstr, VARDATA(bstr), len);
workstr = (char *) palloc(len);
memcpy(workstr, VARDATA(bstr), len);
}
else
workstr = NULL;
if ((Pointer) bstr != DatumGetPointer(str_const->constvalue)) if ((Pointer) bstr != DatumGetPointer(str_const->constvalue))
pfree(bstr); pfree(bstr);
} }
@ -4429,8 +4414,7 @@ make_greater_string(const Const *str_const)
} }
/* Failed... */ /* Failed... */
if (workstr != NULL) pfree(workstr);
pfree(workstr);
return NULL; return NULL;
} }