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Fix more multibyte issues in ltree.

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Commit 84d5efa7e3 missed some multibyte issues caused by short-circuit
logic in the callers. The callers assumed that if the predicate string
is longer than the label string, then it couldn't possibly be a match,
but it can be when using case-insensitive matching (LVAR_INCASE) if
casefolding changes the byte length.

Fix by refactoring to get rid of the short-circuit logic as well as
the function pointer, and consolidate the logic in a replacement
function ltree_label_match().

Discussion: https://postgr.es/m/02c6ef6cf56a5013ede61ad03c7a26affd27d449.camel@j-davis.com
Backpatch-through: 14
REL_18_STABLE
Jeff Davis 2 months ago
parent 4abf63c62b
commit b3c2a3d386
3 changed files with 63 additions and 69 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 111
      contrib/ltree/lquery_op.c
  2. 10
      contrib/ltree/ltree.h
  3. 11
      contrib/ltree/ltxtquery_op.c

111
contrib/ltree/lquery_op.c
Unescape View File

@ -41,8 +41,7 @@ getlexeme(char *start, char *end, int *len)
}
bool
compare_subnode(ltree_level *t, char *qn, int len,
ltree_prefix_eq_func prefix_eq, bool anyend)
compare_subnode(ltree_level *t, char *qn, int len, bool prefix, bool ci)
{
char *endt = t->name + t->len;
char *endq = qn + len;
@ -57,10 +56,8 @@ compare_subnode(ltree_level *t, char *qn, int len,
isok = false;
while ((tn = getlexeme(tn, endt, &lent)) != NULL)
{
if ((lent == lenq || (lent > lenq && anyend)) &&
(*prefix_eq) (qn, lenq, tn, lent))
if (ltree_label_match(qn, lenq, tn, lent, prefix, ci))
{
isok = true;
break;
}
@ -76,81 +73,84 @@ compare_subnode(ltree_level *t, char *qn, int len,
}
/*
* Check if 'a' is a prefix of 'b'.
*/
bool
ltree_prefix_eq(const char *a, size_t a_sz, const char *b, size_t b_sz)
{
if (a_sz > b_sz)
return false;
else
return (strncmp(a, b, a_sz) == 0);
}
/*
* Case-insensitive check if 'a' is a prefix of 'b'.
* Check if the label matches the predicate string. If 'prefix' is true, then
* the predicate string is treated as a prefix. If 'ci' is true, then the
* predicate string is case-insensitive (and locale-aware).
*/
bool
ltree_prefix_eq_ci(const char *a, size_t a_sz, const char *b, size_t b_sz)
ltree_label_match(const char *pred, size_t pred_len, const char *label,
size_t label_len, bool prefix, bool ci)
{
static pg_locale_t locale = NULL;
size_t al_sz = a_sz + 1;
size_t al_len;
char *al;
size_t bl_sz = b_sz + 1;
size_t bl_len;
char *bl;
char *fpred; /* casefolded predicate */
size_t fpred_len = pred_len;
char *flabel; /* casefolded label */
size_t flabel_len = label_len;
size_t len;
bool res;
/* fast path for binary match or binary prefix match */
if ((pred_len == label_len || (prefix && pred_len < label_len)) &&
strncmp(pred, label, pred_len) == 0)
return true;
else if (!ci)
return false;
if (!locale)
locale = pg_newlocale_from_collation(DEFAULT_COLLATION_OID);
if (locale->ctype_is_c)
{
if (a_sz > b_sz)
if (pred_len > label_len)
return false;
for (int i = 0; i < a_sz; i++)
for (int i = 0; i < pred_len; i++)
{
if (pg_ascii_tolower(a[i]) != pg_ascii_tolower(b[i]))
if (pg_ascii_tolower(pred[i]) != pg_ascii_tolower(label[i]))
return false;
}
return true;
}
al = palloc(al_sz);
bl = palloc(bl_sz);
/* casefold both a and b */
/*
* Slow path for case-insensitive comparison: case fold and then compare.
* This path is necessary even if pred_len > label_len, because the byte
* lengths may change after casefolding.
*/
al_len = pg_strfold(al, al_sz, a, a_sz, locale);
if (al_len + 1 > al_sz)
fpred = palloc(fpred_len + 1);
len = pg_strfold(fpred, fpred_len + 1, pred, pred_len, locale);
if (len > fpred_len)
{
/* 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);
fpred_len = len;
fpred = repalloc(fpred, fpred_len + 1);
len = pg_strfold(fpred, fpred_len + 1, pred, pred_len, locale);
}
Assert(len <= fpred_len);
fpred_len = len;
bl_len = pg_strfold(bl, bl_sz, b, b_sz, locale);
if (bl_len + 1 > bl_sz)
flabel = palloc(flabel_len + 1);
len = pg_strfold(flabel, flabel_len + 1, label, label_len, locale);
if (len > flabel_len)
{
/* 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);
flabel_len = len;
flabel = repalloc(flabel, flabel_len + 1);
len = pg_strfold(flabel, flabel_len + 1, label, label_len, locale);
}
Assert(len <= flabel_len);
flabel_len = len;
if (al_len > bl_len)
res = false;
if ((fpred_len == flabel_len || (prefix && fpred_len < flabel_len)) &&
strncmp(fpred, flabel, fpred_len) == 0)
res = true;
else
res = (strncmp(al, bl, al_len) == 0);
res = false;
pfree(al);
pfree(bl);
pfree(fpred);
pfree(flabel);
return res;
}
@ -175,19 +175,16 @@ checkLevel(lquery_level *curq, ltree_level *curt)
for (int i = 0; i < curq->numvar; i++)
{
ltree_prefix_eq_func prefix_eq;
prefix_eq = (curvar->flag & LVAR_INCASE) ? ltree_prefix_eq_ci : ltree_prefix_eq;
bool prefix = (curvar->flag & LVAR_ANYEND);
bool ci = (curvar->flag & LVAR_INCASE);
if (curvar->flag & LVAR_SUBLEXEME)
{
if (compare_subnode(curt, curvar->name, curvar->len, prefix_eq,
(curvar->flag & LVAR_ANYEND)))
if (compare_subnode(curt, curvar->name, curvar->len, prefix, ci))
return success;
}
else if ((curvar->len == curt->len ||
(curt->len > curvar->len && (curvar->flag & LVAR_ANYEND))) &&
(*prefix_eq) (curvar->name, curvar->len, curt->name, curt->len))
else if (ltree_label_match(curvar->name, curvar->len, curt->name,
curt->len, prefix, ci))
return success;
curvar = LVAR_NEXT(curvar);

10
contrib/ltree/ltree.h
Unescape View File

@ -157,8 +157,6 @@ typedef struct
char data[FLEXIBLE_ARRAY_MEMBER];
} ltxtquery;
typedef bool (*ltree_prefix_eq_func) (const char *, size_t, const char *, size_t);
#define HDRSIZEQT MAXALIGN(VARHDRSZ + sizeof(int32))
#define COMPUTESIZE(size,lenofoperand) ( HDRSIZEQT + (size) * sizeof(ITEM) + (lenofoperand) )
#define LTXTQUERY_TOO_BIG(size,lenofoperand) \
@ -209,11 +207,11 @@ bool ltree_execute(ITEM *curitem, void *checkval,
int ltree_compare(const ltree *a, const ltree *b);
bool inner_isparent(const ltree *c, const ltree *p);
bool compare_subnode(ltree_level *t, char *qn, int len,
ltree_prefix_eq_func prefix_eq, bool anyend);
bool compare_subnode(ltree_level *t, char *qn, int len, bool prefix, bool ci);
ltree *lca_inner(ltree **a, int len);
bool 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);
bool ltree_label_match(const char *pred, size_t pred_len,
const char *label, size_t label_len,
bool prefix, bool ci);
/* fmgr macros for ltree objects */
#define DatumGetLtreeP(X) ((ltree *) PG_DETOAST_DATUM(X))

11
contrib/ltree/ltxtquery_op.c
Unescape View File

@ -58,19 +58,18 @@ checkcondition_str(void *checkval, ITEM *val)
ltree_level *level = LTREE_FIRST(((CHKVAL *) checkval)->node);
int tlen = ((CHKVAL *) checkval)->node->numlevel;
char *op = ((CHKVAL *) checkval)->operand + val->distance;
ltree_prefix_eq_func prefix_eq;
bool prefix = (val->flag & LVAR_ANYEND);
bool ci = (val->flag & LVAR_INCASE);
prefix_eq = (val->flag & LVAR_INCASE) ? ltree_prefix_eq_ci : ltree_prefix_eq;
while (tlen > 0)
{
if (val->flag & LVAR_SUBLEXEME)
{
if (compare_subnode(level, op, val->length, prefix_eq, (val->flag & LVAR_ANYEND)))
if (compare_subnode(level, op, val->length, prefix, ci))
return true;
}
else if ((val->length == level->len ||
(level->len > val->length && (val->flag & LVAR_ANYEND))) &&
(*prefix_eq) (op, val->length, level->name, level->len))
else if (ltree_label_match(op, val->length, level->name, level->len,
prefix, ci))
return true;
tlen--;

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