From e15d53e7a419dcff49e108c78c8f70be6b18598b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 2 Jan 2010 20:59:16 +0000
Subject: [PATCH] Fix similar_escape() to convert parentheses to non-capturing
style. This is needed to avoid unwanted interference with SUBSTRING behavior,
as per bug #5257 from Roman Kononov. Also, add some basic intelligence about
character classes (bracket expressions) since we now have several behaviors
that aren't appropriate inside a character class.
As with the previous patch in this area, I'm reluctant to back-patch
since it might affect applications that are relying on the prior
behavior.
---
src/backend/utils/adt/regexp.c | 31 ++++++++++++++++++++++++++-----
1 file changed, 26 insertions(+), 5 deletions(-)
diff --git a/src/backend/utils/adt/regexp.c b/src/backend/utils/adt/regexp.c
index ca61d5637f9..cbffcdb1835 100644
--- a/src/backend/utils/adt/regexp.c
+++ b/src/backend/utils/adt/regexp.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/regexp.c,v 1.85 2010/01/02 16:57:55 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/regexp.c,v 1.86 2010/01/02 20:59:16 tgl Exp $
*
* Alistair Crooks added the code for the regex caching
* agc - cached the regular expressions used - there's a good chance
@@ -640,6 +640,7 @@ similar_escape(PG_FUNCTION_ARGS)
int plen,
elen;
bool afterescape = false;
+ bool incharclass = false;
int nquotes = 0;
/* This function is not strict, so must test explicitly */
@@ -682,10 +683,10 @@ similar_escape(PG_FUNCTION_ARGS)
*/
/*
- * We need room for the prefix/postfix plus as many as 2 output bytes per
- * input byte
+ * We need room for the prefix/postfix plus as many as 3 output bytes per
+ * input byte; since the input is at most 1GB this can't overflow
*/
- result = (text *) palloc(VARHDRSZ + 6 + 2 * plen);
+ result = (text *) palloc(VARHDRSZ + 6 + 3 * plen);
r = VARDATA(result);
*r++ = '^';
@@ -699,7 +700,7 @@ similar_escape(PG_FUNCTION_ARGS)
if (afterescape)
{
- if (pchar == '"') /* for SUBSTRING patterns */
+ if (pchar == '"' && !incharclass) /* for SUBSTRING patterns */
*r++ = ((nquotes++ % 2) == 0) ? '(' : ')';
else
{
@@ -713,6 +714,19 @@ similar_escape(PG_FUNCTION_ARGS)
/* SQL99 escape character; do not send to output */
afterescape = true;
}
+ else if (incharclass)
+ {
+ if (pchar == '\\')
+ *r++ = '\\';
+ *r++ = pchar;
+ if (pchar == ']')
+ incharclass = false;
+ }
+ else if (pchar == '[')
+ {
+ *r++ = pchar;
+ incharclass = true;
+ }
else if (pchar == '%')
{
*r++ = '.';
@@ -720,6 +734,13 @@ similar_escape(PG_FUNCTION_ARGS)
}
else if (pchar == '_')
*r++ = '.';
+ else if (pchar == '(')
+ {
+ /* convert to non-capturing parenthesis */
+ *r++ = '(';
+ *r++ = '?';
+ *r++ = ':';
+ }
else if (pchar == '\\' || pchar == '.' ||
pchar == '^' || pchar == '$')
{
--
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