summaryrefslogtreecommitdiff
path: root/src
diff options
context:
space:
mode:
authorJeff Davis2025-12-16 23:32:41 +0000
committerJeff Davis2025-12-16 23:32:41 +0000
commit87b2968df0f866aaccb6ba69adf284e3c4a79454 (patch)
tree83669f96e2198bc8dda0666e7e8b0805c77f95a9 /src
parent7f007e4a044a713df5320fca09621d6ba8e632ba (diff)
downcase_identifier(): use method table from locale provider.
Previously, libc's tolower() was always used for lowercasing identifiers, regardless of the database locale (though only characters beyond 127 in single-byte encodings were affected). Refactor to allow each provider to supply its own implementation of identifier downcasing. For historical compatibility, when using a single-byte encoding, ICU still relies on tolower(). One minor behavior change is that, before the database default locale is initialized, it uses ASCII semantics to downcase the identifiers. Previously, it would use the postmaster's LC_CTYPE setting from the environment. While that could have some effect during GUC processing, for example, it would have been fragile to rely on the environment setting anyway. (Also, it only matters when the encoding is single-byte.) Reviewed-by: Chao Li <li.evan.chao@gmail.com> Reviewed-by: Peter Eisentraut <peter@eisentraut.org> Discussion: https://postgr.es/m/450ceb6260cad30d7afdf155d991a9caafee7c0d.camel@j-davis.com
Diffstat (limited to 'src')
-rw-r--r--src/backend/parser/scansup.c36
-rw-r--r--src/backend/utils/adt/pg_locale.c20
-rw-r--r--src/backend/utils/adt/pg_locale_builtin.c2
-rw-r--r--src/backend/utils/adt/pg_locale_icu.c36
-rw-r--r--src/backend/utils/adt/pg_locale_libc.c33
-rw-r--r--src/include/utils/pg_locale.h5
6 files changed, 107 insertions, 25 deletions
diff --git a/src/backend/parser/scansup.c b/src/backend/parser/scansup.c
index 2feb2b6cf5a..d63cb865260 100644
--- a/src/backend/parser/scansup.c
+++ b/src/backend/parser/scansup.c
@@ -18,6 +18,7 @@
#include "mb/pg_wchar.h"
#include "parser/scansup.h"
+#include "utils/pg_locale.h"
/*
@@ -46,35 +47,22 @@ char *
downcase_identifier(const char *ident, int len, bool warn, bool truncate)
{
char *result;
- int i;
- bool enc_is_single_byte;
-
- result = palloc(len + 1);
- enc_is_single_byte = pg_database_encoding_max_length() == 1;
+ size_t needed pg_attribute_unused();
/*
- * SQL99 specifies Unicode-aware case normalization, which we don't yet
- * have the infrastructure for. Instead we use tolower() to provide a
- * locale-aware translation. However, there are some locales where this
- * is not right either (eg, Turkish may do strange things with 'i' and
- * 'I'). Our current compromise is to use tolower() for characters with
- * the high bit set, as long as they aren't part of a multi-byte
- * character, and use an ASCII-only downcasing for 7-bit characters.
+ * Preserves string length.
+ *
+ * NB: if we decide to support Unicode-aware identifier case folding, then
+ * we need to account for a change in string length.
*/
- for (i = 0; i < len; i++)
- {
- unsigned char ch = (unsigned char) ident[i];
+ result = palloc(len + 1);
- if (ch >= 'A' && ch <= 'Z')
- ch += 'a' - 'A';
- else if (enc_is_single_byte && IS_HIGHBIT_SET(ch) && isupper(ch))
- ch = tolower(ch);
- result[i] = (char) ch;
- }
- result[i] = '\0';
+ needed = pg_downcase_ident(result, len + 1, ident, len);
+ Assert(needed == len);
+ Assert(result[len] == '\0');
- if (i >= NAMEDATALEN && truncate)
- truncate_identifier(result, i, warn);
+ if (len >= NAMEDATALEN && truncate)
+ truncate_identifier(result, len, warn);
return result;
}
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index 8a3796aa5d0..ee08ac045b7 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/src/backend/utils/adt/pg_locale.c
@@ -1353,6 +1353,26 @@ pg_strfold(char *dst, size_t dstsize, const char *src, ssize_t srclen,
}
/*
+ * Lowercase an identifier using the database default locale.
+ *
+ * For historical reasons, does not use ordinary locale behavior. Should only
+ * be used for identifiers. XXX: can we make this equivalent to
+ * pg_strfold(..., default_locale)?
+ */
+size_t
+pg_downcase_ident(char *dst, size_t dstsize, const char *src, ssize_t srclen)
+{
+ pg_locale_t locale = default_locale;
+
+ if (locale == NULL || locale->ctype == NULL ||
+ locale->ctype->downcase_ident == NULL)
+ return strlower_c(dst, dstsize, src, srclen);
+ else
+ return locale->ctype->downcase_ident(dst, dstsize, src, srclen,
+ locale);
+}
+
+/*
* pg_strcoll
*
* Like pg_strncoll for NUL-terminated input strings.
diff --git a/src/backend/utils/adt/pg_locale_builtin.c b/src/backend/utils/adt/pg_locale_builtin.c
index 0c2920112bb..145b4641b1b 100644
--- a/src/backend/utils/adt/pg_locale_builtin.c
+++ b/src/backend/utils/adt/pg_locale_builtin.c
@@ -208,6 +208,8 @@ static const struct ctype_methods ctype_methods_builtin = {
.strtitle = strtitle_builtin,
.strupper = strupper_builtin,
.strfold = strfold_builtin,
+ /* uses plain ASCII semantics for historical reasons */
+ .downcase_ident = NULL,
.wc_isdigit = wc_isdigit_builtin,
.wc_isalpha = wc_isalpha_builtin,
.wc_isalnum = wc_isalnum_builtin,
diff --git a/src/backend/utils/adt/pg_locale_icu.c b/src/backend/utils/adt/pg_locale_icu.c
index 18d026deda8..69f22b47a68 100644
--- a/src/backend/utils/adt/pg_locale_icu.c
+++ b/src/backend/utils/adt/pg_locale_icu.c
@@ -61,6 +61,8 @@ static size_t strupper_icu(char *dest, size_t destsize, const char *src,
ssize_t srclen, pg_locale_t locale);
static size_t strfold_icu(char *dest, size_t destsize, const char *src,
ssize_t srclen, pg_locale_t locale);
+static size_t downcase_ident_icu(char *dst, size_t dstsize, const char *src,
+ ssize_t srclen, pg_locale_t locale);
static int strncoll_icu(const char *arg1, ssize_t len1,
const char *arg2, ssize_t len2,
pg_locale_t locale);
@@ -123,7 +125,7 @@ static int32_t u_strFoldCase_default(UChar *dest, int32_t destCapacity,
/*
* XXX: many of the functions below rely on casts directly from pg_wchar to
- * UChar32, which is correct for the UTF-8 encoding, but not in general.
+ * UChar32, which is correct for UTF-8 and LATIN1, but not in general.
*/
static pg_wchar
@@ -227,6 +229,7 @@ static const struct ctype_methods ctype_methods_icu = {
.strtitle = strtitle_icu,
.strupper = strupper_icu,
.strfold = strfold_icu,
+ .downcase_ident = downcase_ident_icu,
.wc_isdigit = wc_isdigit_icu,
.wc_isalpha = wc_isalpha_icu,
.wc_isalnum = wc_isalnum_icu,
@@ -565,6 +568,37 @@ strfold_icu(char *dest, size_t destsize, const char *src, ssize_t srclen,
}
/*
+ * For historical compatibility, behavior is not multibyte-aware.
+ *
+ * NB: uses libc tolower() for single-byte encodings (also for historical
+ * compatibility), and therefore relies on the global LC_CTYPE setting.
+ */
+static size_t
+downcase_ident_icu(char *dst, size_t dstsize, const char *src,
+ ssize_t srclen, pg_locale_t locale)
+{
+ int i;
+ bool enc_is_single_byte;
+
+ enc_is_single_byte = pg_database_encoding_max_length() == 1;
+ for (i = 0; i < srclen && i < dstsize; i++)
+ {
+ unsigned char ch = (unsigned char) src[i];
+
+ if (ch >= 'A' && ch <= 'Z')
+ ch = pg_ascii_tolower(ch);
+ else if (enc_is_single_byte && IS_HIGHBIT_SET(ch) && isupper(ch))
+ ch = tolower(ch);
+ dst[i] = (char) ch;
+ }
+
+ if (i < dstsize)
+ dst[i] = '\0';
+
+ return srclen;
+}
+
+/*
* strncoll_icu_utf8
*
* Call ucol_strcollUTF8() or ucol_strcoll() as appropriate for the given
diff --git a/src/backend/utils/adt/pg_locale_libc.c b/src/backend/utils/adt/pg_locale_libc.c
index 3baa5816b5f..ab6117aaace 100644
--- a/src/backend/utils/adt/pg_locale_libc.c
+++ b/src/backend/utils/adt/pg_locale_libc.c
@@ -318,12 +318,41 @@ tolower_libc_mb(pg_wchar wc, pg_locale_t locale)
return wc;
}
+/*
+ * Characters A..Z always downcase to a..z, even in the Turkish
+ * locale. Characters beyond 127 use tolower().
+ */
+static size_t
+downcase_ident_libc_sb(char *dst, size_t dstsize, const char *src,
+ ssize_t srclen, pg_locale_t locale)
+{
+ locale_t loc = locale->lt;
+ int i;
+
+ for (i = 0; i < srclen && i < dstsize; i++)
+ {
+ unsigned char ch = (unsigned char) src[i];
+
+ if (ch >= 'A' && ch <= 'Z')
+ ch = pg_ascii_tolower(ch);
+ else if (IS_HIGHBIT_SET(ch) && isupper_l(ch, loc))
+ ch = tolower_l(ch, loc);
+ dst[i] = (char) ch;
+ }
+
+ if (i < dstsize)
+ dst[i] = '\0';
+
+ return srclen;
+}
+
static const struct ctype_methods ctype_methods_libc_sb = {
.strlower = strlower_libc_sb,
.strtitle = strtitle_libc_sb,
.strupper = strupper_libc_sb,
/* in libc, casefolding is the same as lowercasing */
.strfold = strlower_libc_sb,
+ .downcase_ident = downcase_ident_libc_sb,
.wc_isdigit = wc_isdigit_libc_sb,
.wc_isalpha = wc_isalpha_libc_sb,
.wc_isalnum = wc_isalnum_libc_sb,
@@ -349,6 +378,8 @@ static const struct ctype_methods ctype_methods_libc_other_mb = {
.strupper = strupper_libc_mb,
/* in libc, casefolding is the same as lowercasing */
.strfold = strlower_libc_mb,
+ /* uses plain ASCII semantics for historical reasons */
+ .downcase_ident = NULL,
.wc_isdigit = wc_isdigit_libc_sb,
.wc_isalpha = wc_isalpha_libc_sb,
.wc_isalnum = wc_isalnum_libc_sb,
@@ -370,6 +401,8 @@ static const struct ctype_methods ctype_methods_libc_utf8 = {
.strupper = strupper_libc_mb,
/* in libc, casefolding is the same as lowercasing */
.strfold = strlower_libc_mb,
+ /* uses plain ASCII semantics for historical reasons */
+ .downcase_ident = NULL,
.wc_isdigit = wc_isdigit_libc_mb,
.wc_isalpha = wc_isalpha_libc_mb,
.wc_isalnum = wc_isalnum_libc_mb,
diff --git a/src/include/utils/pg_locale.h b/src/include/utils/pg_locale.h
index 6cf1985963d..1e584819c5e 100644
--- a/src/include/utils/pg_locale.h
+++ b/src/include/utils/pg_locale.h
@@ -110,6 +110,9 @@ struct ctype_methods
size_t (*strfold) (char *dest, size_t destsize,
const char *src, ssize_t srclen,
pg_locale_t locale);
+ size_t (*downcase_ident) (char *dest, size_t destsize,
+ const char *src, ssize_t srclen,
+ pg_locale_t locale);
/* required */
bool (*wc_isdigit) (pg_wchar wc, pg_locale_t locale);
@@ -187,6 +190,8 @@ extern size_t pg_strupper(char *dst, size_t dstsize,
extern size_t pg_strfold(char *dst, size_t dstsize,
const char *src, ssize_t srclen,
pg_locale_t locale);
+extern size_t pg_downcase_ident(char *dst, size_t dstsize,
+ const char *src, ssize_t srclen);
extern int pg_strcoll(const char *arg1, const char *arg2, pg_locale_t locale);
extern int pg_strncoll(const char *arg1, ssize_t len1,
const char *arg2, ssize_t len2, pg_locale_t locale);
generated by cgit v1.2.3 (git 2.39.1) at 2025-12-17 17:10:50 +0000