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Fix regexp substring matching (substring(string from pattern)) for the corner

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case where there is a match to the pattern overall but the user has specified
a parenthesized subexpression and that subexpression hasn't got a match.
An example is substring('foo' from 'foo(bar)?').  This should return NULL,
since (bar) isn't matched, but it was mistakenly returning the whole-pattern
match instead (ie, 'foo').  Per bug #4044 from Rui Martins.

This has been broken since the beginning; patch in all supported versions.
The old behavior was sufficiently inconsistent that it's impossible to believe
anyone is depending on it.
This commit is contained in:
Tom Lane
2008-03-19 02:41:15 +00:00
parent 0d52d7a71e
commit a1453f121b
1 changed files with 118 additions and 87 deletions
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197
src/backend/utils/adt/regexp.c
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@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.49.4.4 2007/01/03 22:39:56 tgl Exp $ * $Header: /cvsroot/pgsql/src/backend/utils/adt/regexp.c,v 1.49.4.5 2008/03/19 02:41:15 tgl Exp $
* *
* Alistair Crooks added the code for the regex caching * Alistair Crooks added the code for the regex caching
* agc - cached the regular expressions used - there's a good chance * agc - cached the regular expressions used - there's a good chance
@ -80,42 +80,31 @@ static cached_re_str re_array[MAX_CACHED_RES]; /* cached re's */
/* /*
* RE_compile_and_execute - compile and execute a RE, caching if possible * RE_compile_and_cache - compile a RE, caching if possible
* *
* Returns TRUE on match, FALSE on no match * Returns regex_t *
* *
* text_re --- the pattern, expressed as an *untoasted* TEXT object * text_re --- the pattern, expressed as an *untoasted* TEXT object
* dat --- the data to match against (need not be null-terminated)
* dat_len --- the length of the data string
* cflags --- compile options for the pattern * cflags --- compile options for the pattern
* nmatch, pmatch --- optional return area for match details
* *
* Both pattern and data are given in the database encoding. We internally * Pattern is given in the database encoding. We internally convert to
* convert to array of pg_wchar which is what Spencer's regex package wants. * array of pg_wchar which is what Spencer's regex package wants.
*/ */
static bool static regex_t *
RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len, RE_compile_and_cache(text *text_re, int cflags)
int cflags, int nmatch, regmatch_t *pmatch)
{ {
int text_re_len = VARSIZE(text_re); int text_re_len = VARSIZE(text_re);
pg_wchar *data;
size_t data_len;
pg_wchar *pattern; pg_wchar *pattern;
size_t pattern_len; size_t pattern_len;
int i; int i;
int regcomp_result; int regcomp_result;
int regexec_result;
cached_re_str re_temp; cached_re_str re_temp;
char errMsg[100]; char errMsg[100];
/* Convert data string to wide characters */
data = (pg_wchar *) palloc((dat_len + 1) * sizeof(pg_wchar));
data_len = pg_mb2wchar_with_len(dat, data, dat_len);
/* /*
* Look for a match among previously compiled REs. Since the data * Look for a match among previously compiled REs. Since the data
* structure is self-organizing with most-used entries at the front, * structure is self-organizing with most-used entries at the front, our
* our search strategy can just be to scan from the front. * search strategy can just be to scan from the front.
*/ */
for (i = 0; i < num_res; i++) for (i = 0; i < num_res; i++)
{ {
@ -133,28 +122,7 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
re_array[0] = re_temp; re_array[0] = re_temp;
} }
/* Perform RE match and return result */ return &re_array[0].cre_re;
regexec_result = pg_regexec(&re_array[0].cre_re,
data,
data_len,
NULL, /* no details */
nmatch,
pmatch,
0);
pfree(data);
if (regexec_result != REG_OKAY && regexec_result != REG_NOMATCH)
{
/* re failed??? */
pg_regerror(regexec_result, &re_array[0].cre_re,
errMsg, sizeof(errMsg));
ereport(ERROR,
(errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
errmsg("regular expression failed: %s", errMsg)));
}
return (regexec_result == REG_OKAY);
} }
} }
@ -165,7 +133,7 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
/* Convert pattern string to wide characters */ /* Convert pattern string to wide characters */
pattern = (pg_wchar *) palloc((text_re_len - VARHDRSZ + 1) * sizeof(pg_wchar)); pattern = (pg_wchar *) palloc((text_re_len - VARHDRSZ + 1) * sizeof(pg_wchar));
pattern_len = pg_mb2wchar_with_len((unsigned char *) VARDATA(text_re), pattern_len = pg_mb2wchar_with_len(VARDATA(text_re),
pattern, pattern,
text_re_len - VARHDRSZ); text_re_len - VARHDRSZ);
@ -202,8 +170,8 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
re_temp.cre_flags = cflags; re_temp.cre_flags = cflags;
/* /*
* Okay, we have a valid new item in re_temp; insert it into the * Okay, we have a valid new item in re_temp; insert it into the storage
* storage array. Discard last entry if needed. * array. Discard last entry if needed.
*/ */
if (num_res >= MAX_CACHED_RES) if (num_res >= MAX_CACHED_RES)
{ {
@ -219,8 +187,37 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
re_array[0] = re_temp; re_array[0] = re_temp;
num_res++; num_res++;
return &re_array[0].cre_re;
}
/*
* RE_execute - execute a RE
*
* Returns TRUE on match, FALSE on no match
*
* re --- the compiled pattern as returned by RE_compile_and_cache
* dat --- the data to match against (need not be null-terminated)
* dat_len --- the length of the data string
* nmatch, pmatch --- optional return area for match details
*
* Data is given in the database encoding. We internally
* convert to array of pg_wchar which is what Spencer's regex package wants.
*/
static bool
RE_execute(regex_t *re, char *dat, int dat_len,
int nmatch, regmatch_t *pmatch)
{
pg_wchar *data;
size_t data_len;
int regexec_result;
char errMsg[100];
/* Convert data string to wide characters */
data = (pg_wchar *) palloc((dat_len + 1) * sizeof(pg_wchar));
data_len = pg_mb2wchar_with_len(dat, data, dat_len);
/* Perform RE match and return result */ /* Perform RE match and return result */
regexec_result = pg_regexec(&re_array[0].cre_re, regexec_result = pg_regexec(re,
data, data,
data_len, data_len,
NULL, /* no details */ NULL, /* no details */
@ -233,8 +230,7 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
if (regexec_result != REG_OKAY && regexec_result != REG_NOMATCH) if (regexec_result != REG_OKAY && regexec_result != REG_NOMATCH)
{ {
/* re failed??? */ /* re failed??? */
pg_regerror(regexec_result, &re_array[0].cre_re, pg_regerror(regexec_result, re, errMsg, sizeof(errMsg));
errMsg, sizeof(errMsg));
ereport(ERROR, ereport(ERROR,
(errcode(ERRCODE_INVALID_REGULAR_EXPRESSION), (errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
errmsg("regular expression failed: %s", errMsg))); errmsg("regular expression failed: %s", errMsg)));
@ -243,6 +239,33 @@ RE_compile_and_execute(text *text_re, unsigned char *dat, int dat_len,
return (regexec_result == REG_OKAY); return (regexec_result == REG_OKAY);
} }
/*
* RE_compile_and_execute - compile and execute a RE
*
* Returns TRUE on match, FALSE on no match
*
* text_re --- the pattern, expressed as an *untoasted* TEXT object
* dat --- the data to match against (need not be null-terminated)
* dat_len --- the length of the data string
* cflags --- compile options for the pattern
* nmatch, pmatch --- optional return area for match details
*
* Both pattern and data are given in the database encoding. We internally
* convert to array of pg_wchar which is what Spencer's regex package wants.
*/
static bool
RE_compile_and_execute(text *text_re, char *dat, int dat_len,
int cflags, int nmatch, regmatch_t *pmatch)
{
regex_t *re;
/* Compile RE */
re = RE_compile_and_cache(text_re, cflags);
/* Perform RE match and return result */
return RE_execute(re, dat, dat_len, nmatch, pmatch);
}
/* /*
* assign_regex_flavor - GUC hook to validate and set REGEX_FLAVOR * assign_regex_flavor - GUC hook to validate and set REGEX_FLAVOR
@ -283,7 +306,7 @@ nameregexeq(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(RE_compile_and_execute(p, PG_RETURN_BOOL(RE_compile_and_execute(p,
(unsigned char *) NameStr(*n), NameStr(*n),
strlen(NameStr(*n)), strlen(NameStr(*n)),
regex_flavor, regex_flavor,
0, NULL)); 0, NULL));
@ -296,7 +319,7 @@ nameregexne(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p, PG_RETURN_BOOL(!RE_compile_and_execute(p,
(unsigned char *) NameStr(*n), NameStr(*n),
strlen(NameStr(*n)), strlen(NameStr(*n)),
regex_flavor, regex_flavor,
0, NULL)); 0, NULL));
@ -309,7 +332,7 @@ textregexeq(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(RE_compile_and_execute(p, PG_RETURN_BOOL(RE_compile_and_execute(p,
(unsigned char *) VARDATA(s), VARDATA(s),
VARSIZE(s) - VARHDRSZ, VARSIZE(s) - VARHDRSZ,
regex_flavor, regex_flavor,
0, NULL)); 0, NULL));
@ -322,7 +345,7 @@ textregexne(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p, PG_RETURN_BOOL(!RE_compile_and_execute(p,
(unsigned char *) VARDATA(s), VARDATA(s),
VARSIZE(s) - VARHDRSZ, VARSIZE(s) - VARHDRSZ,
regex_flavor, regex_flavor,
0, NULL)); 0, NULL));
@ -342,7 +365,7 @@ nameicregexeq(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(RE_compile_and_execute(p, PG_RETURN_BOOL(RE_compile_and_execute(p,
(unsigned char *) NameStr(*n), NameStr(*n),
strlen(NameStr(*n)), strlen(NameStr(*n)),
regex_flavor | REG_ICASE, regex_flavor | REG_ICASE,
0, NULL)); 0, NULL));
@ -355,7 +378,7 @@ nameicregexne(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p, PG_RETURN_BOOL(!RE_compile_and_execute(p,
(unsigned char *) NameStr(*n), NameStr(*n),
strlen(NameStr(*n)), strlen(NameStr(*n)),
regex_flavor | REG_ICASE, regex_flavor | REG_ICASE,
0, NULL)); 0, NULL));
@ -368,7 +391,7 @@ texticregexeq(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(RE_compile_and_execute(p, PG_RETURN_BOOL(RE_compile_and_execute(p,
(unsigned char *) VARDATA(s), VARDATA(s),
VARSIZE(s) - VARHDRSZ, VARSIZE(s) - VARHDRSZ,
regex_flavor | REG_ICASE, regex_flavor | REG_ICASE,
0, NULL)); 0, NULL));
@ -381,7 +404,7 @@ texticregexne(PG_FUNCTION_ARGS)
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
PG_RETURN_BOOL(!RE_compile_and_execute(p, PG_RETURN_BOOL(!RE_compile_and_execute(p,
(unsigned char *) VARDATA(s), VARDATA(s),
VARSIZE(s) - VARHDRSZ, VARSIZE(s) - VARHDRSZ,
regex_flavor | REG_ICASE, regex_flavor | REG_ICASE,
0, NULL)); 0, NULL));
@ -397,43 +420,51 @@ textregexsubstr(PG_FUNCTION_ARGS)
{ {
text *s = PG_GETARG_TEXT_P(0); text *s = PG_GETARG_TEXT_P(0);
text *p = PG_GETARG_TEXT_P(1); text *p = PG_GETARG_TEXT_P(1);
bool match; regex_t *re;
regmatch_t pmatch[2]; regmatch_t pmatch[2];
/*
* We pass two regmatch_t structs to get info about the overall match
* and the match for the first parenthesized subexpression (if any).
* If there is a parenthesized subexpression, we return what it
* matched; else return what the whole regexp matched.
*/
match = RE_compile_and_execute(p,
(unsigned char *) VARDATA(s),
VARSIZE(s) - VARHDRSZ,
regex_flavor,
2, pmatch);
/* match? then return the substring matching the pattern */
if (match)
{
int so, int so,
eo; eo;
/* Compile RE */
re = RE_compile_and_cache(p, regex_flavor);
/*
* We pass two regmatch_t structs to get info about the overall match and
* the match for the first parenthesized subexpression (if any). If there
* is a parenthesized subexpression, we return what it matched; else
* return what the whole regexp matched.
*/
if (!RE_execute(re,
VARDATA(s), VARSIZE(s) - VARHDRSZ,
2, pmatch))
PG_RETURN_NULL(); /* definitely no match */
if (re->re_nsub > 0)
{
/* has parenthesized subexpressions, use the first one */
so = pmatch[1].rm_so; so = pmatch[1].rm_so;
eo = pmatch[1].rm_eo; eo = pmatch[1].rm_eo;
if (so < 0 || eo < 0) }
else
{ {
/* no parenthesized subexpression */ /* no parenthesized subexpression, use whole match */
so = pmatch[0].rm_so; so = pmatch[0].rm_so;
eo = pmatch[0].rm_eo; eo = pmatch[0].rm_eo;
} }
return (DirectFunctionCall3(text_substr, /*
* It is possible to have a match to the whole pattern but no match
* for a subexpression; for example 'foo(bar)?' is considered to match
* 'foo' but there is no subexpression match. So this extra test for
* match failure is not redundant.
*/
if (so < 0 || eo < 0)
PG_RETURN_NULL();
return DirectFunctionCall3(text_substr,
PointerGetDatum(s), PointerGetDatum(s),
Int32GetDatum(so + 1), Int32GetDatum(so + 1),
Int32GetDatum(eo - so))); Int32GetDatum(eo - so));
}
PG_RETURN_NULL();
} }
/* similar_escape() /* similar_escape()
@ -446,7 +477,7 @@ similar_escape(PG_FUNCTION_ARGS)
text *pat_text; text *pat_text;
text *esc_text; text *esc_text;
text *result; text *result;
unsigned char *p, char *p,
*e, *e,
*r; *r;
int plen, int plen,
@ -513,7 +544,7 @@ similar_escape(PG_FUNCTION_ARGS)
while (plen > 0) while (plen > 0)
{ {
unsigned char pchar = *p; char pchar = *p;
if (afterescape) if (afterescape)
{ {
@ -552,7 +583,7 @@ similar_escape(PG_FUNCTION_ARGS)
*r++ = ')'; *r++ = ')';
*r++ = '$'; *r++ = '$';
VARATT_SIZEP(result) = r - ((unsigned char *) result); VARATT_SIZEP(result) = r - ((char *) result);
PG_RETURN_TEXT_P(result); PG_RETURN_TEXT_P(result);
} }