8000 Eliminate some no-longer-needed workarounds for palloc's old behavior · postgres/postgres@efe2222 · GitHub
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Eliminate some no-longer-needed workarounds for palloc's old behavior
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.
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+21
-37
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1 file changed

+21
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lines changed

‎src/backend/utils/adt/selfuncs.c

Lines changed: 21 additions & 37 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
*
1616
*
1717
* IDENTIFICATION
18-
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.198 2006/03/05 15:58:44 momjian Exp $
18+
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.199 2006/04/20 17:50:18 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -3736,14 +3736,8 @@ like_fixed_prefix(Const *patt_const, bool case_insensitive,
37363736
bytea *bstr = DatumGetByteaP(patt_const->constvalue);
37373737

37383738
pattlen = VARSIZE(bstr) - VARHDRSZ;
3739-
if (pattlen > 0)
3740-
{
3741-
patt = (char *) palloc(pattlen);
3742-
memcpy(patt, VARDATA(bstr), pattlen);
3743-
}
3744-
else
3745-
patt = NULL;
3746-
3739+
patt = (char *) palloc(pattlen);
3740+
memcpy(patt, VARDATA(bstr), pattlen);
37473741
if ((Pointer) bstr != DatumGetPointer(patt_const->constvalue))
37483742
pfree(bstr);
37493743
}
@@ -3761,7 +3755,7 @@ like_fixed_prefix(Const *patt_const, bool case_insensitive,
37613755
if (patt[pos] == '\\')
37623756
{
37633757
pos++;
3764-
if (patt[pos] == '\0' && typeid != BYTEAOID)
3758+
if (pos >= pattlen)
37653759
break;
37663760
}
37673761

@@ -3794,8 +3788,7 @@ like_fixed_prefix(Const *patt_const, bool case_insensitive,
37943788
*rest_const = string_to_bytea_const(rest, pattlen - pos);
37953789
}
37963790

3797-
if (patt != NULL)
3798-
pfree(patt);
3791+
pfree(patt);
37993792
pfree(match);
38003793

38013794
/* in LIKE, an empty pattern is an exact match! */
@@ -4101,7 +4094,6 @@ like_selectivity(Const *patt_const, bool case_insensitive)
41014094
{
41024095
Selectivity sel = 1.0;
41034096
int pos;
4104-
int start;
41054097
Oid typeid = patt_const->consttype;
41064098
char *patt;
41074099
int pattlen;
@@ -4124,23 +4116,20 @@ like_selectivity(Const *patt_const, bool case_insensitive)
41244116
bytea *bstr = DatumGetByteaP(patt_const->constvalue);
41254117

41264118
pattlen = VARSIZE(bstr) - VARHDRSZ;
4127-
if (pattlen > 0)
4128-
{
4129-
patt = (char *) palloc(pattlen);
4130-
memcpy(patt, VARDATA(bstr), pattlen);
4131-
}
4132-
else
4133-
patt = NULL;
4134-
4119+
patt = (char *) palloc(pattlen);
4120+
memcpy(patt, VARDATA(bstr), pattlen);
41354121
if ((Pointer) bstr != DatumGetPointer(patt_const->constvalue))
41364122
pfree(bstr);
41374123
}
4138-
/* patt should never be NULL in practice */
4139-
Assert(patt != NULL);
41404124

4141-
/* Skip any leading %; it's already factored into initial sel */
4142-
start = (*patt == '%') ? 1 : 0;
4143-
for (pos = start; pos < pattlen; pos++)
4125+
/* Skip any leading wildcard; it's already factored into initial sel */
4126+
for (pos = 0; pos < pattlen; pos++)
4127+
{
4128+
if (patt[pos] != '%' && patt[pos] != '_')
4129+
break;
4130+
}
4131+
4132+
for (; pos < pattlen; pos++)
41444133
{
41454134
/* % and _ are wildcard characters in LIKE */
41464135
if (patt[pos] == '%')
@@ -4151,7 +4140,7 @@ like_selectivity(Const *patt_const, bool case_insensitive)
41514140
{
41524141
/* Backslash quotes the next character */
41534142
pos++;
4154-
if (patt[pos] == '\0' && typeid != BYTEAOID)
4143+
if (pos >= pattlen)
41554144
break;
41564145
sel *= FIXED_CHAR_SEL;
41574146
}
@@ -4161,6 +4150,8 @@ like_selectivity(Const *patt_const, bool case_insensitive)
41614150
/* Could get sel > 1 if multiple wildcards */
41624151
if (sel > 1.0)
41634152
sel = 1.0;
4153+
4154+
pfree(patt);
41644155
return sel;
41654156
}
41664157

@@ -4366,14 +4357,8 @@ make_greater_string(const Const *str_const)
43664357
bytea *bstr = DatumGetByteaP(str_const->constvalue);
43674358

43684359
len = VARSIZE(bstr) - VARHDRSZ;
4369-
if (len > 0)
4370-
{
4371-
workstr = (char *) palloc(len);
4372-
memcpy(workstr, VARDATA(bstr), len);
4373-
}
4374-
else
4375-
workstr = NULL;
4376-
4360+
workstr = (char *) palloc(len);
4361+
memcpy(workstr, VARDATA(bstr), len);
43774362
if ((Pointer) bstr != DatumGetPointer(str_const->constvalue))
43784363
pfree(bstr);
43794364
}
@@ -4429,8 +4414,7 @@ make_greater_string(const Const *str_const)
44294414
}
44304415

44314416
/* Failed... */
4432-
if (workstr != NULL)
4433-
pfree(workstr);
4417+
pfree(workstr);
44344418

44354419
return NULL;
44364420
}

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