Prefer pg_any_to_server/pg_server_to_any over pg_do_encoding_conversion.

A large majority of the callers of pg_do_encoding_conversion were
specifying the database encoding as either source or target of the
conversion, meaning that we can use the less general functions
pg_any_to_server/pg_server_to_any instead.

The main advantage of using the latter functions is that they can make use
of a cached conversion-function lookup in the common case that the other
encoding is the current client_encoding.  It's notationally cleaner too in
most cases, not least because of the historical artifact that the latter
functions use "char *" rather than "unsigned char *" in their APIs.

Note that pg_any_to_server will apply an encoding verification step in
some cases where pg_do_encoding_conversion would have just done nothing.
This seems to me to be a good idea at most of these call sites, though
it partially negates the performance benefit.

Per discussion of bug #9210.

1 files changed, 9 insertions, 18 deletions

diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index d36751855b6..765469c623e 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -345,10 +345,7 @@ xml_recv(PG_FUNCTION_ARGS)
 	xmlFreeDoc(doc);
 
 	/* Now that we know what we're dealing with, convert to server encoding */
-	newstr = (char *) pg_do_encoding_conversion((unsigned char *) str,
-												nbytes,
-												encoding,
-												GetDatabaseEncoding());
+	newstr = pg_any_to_server(str, nbytes, encoding);
 
 	if (newstr != str)
 	{
@@ -1793,10 +1790,8 @@ sqlchar_to_unicode(char *s)
 	char	   *utf8string;
 	pg_wchar	ret[2];			/* need space for trailing zero */
 
-	utf8string = (char *) pg_do_encoding_conversion((unsigned char *) s,
-													pg_mblen(s),
-													GetDatabaseEncoding(),
-													PG_UTF8);
+	/* note we're not assuming s is null-terminated */
+	utf8string = pg_server_to_any(s, pg_mblen(s), PG_UTF8);
 
 	pg_encoding_mb2wchar_with_len(PG_UTF8, utf8string, ret,
 								  pg_encoding_mblen(PG_UTF8, utf8string));
@@ -1892,19 +1887,15 @@ map_sql_identifier_to_xml_name(char *ident, bool fully_escaped,
 static char *
 unicode_to_sqlchar(pg_wchar c)
 {
-	unsigned char utf8string[5];	/* need room for trailing zero */
+	char		utf8string[8];			/* need room for trailing zero */
 	char	   *result;
 
 	memset(utf8string, 0, sizeof(utf8string));
-	unicode_to_utf8(c, utf8string);
-
-	result = (char *) pg_do_encoding_conversion(utf8string,
-												pg_encoding_mblen(PG_UTF8,
-														(char *) utf8string),
-												PG_UTF8,
-												GetDatabaseEncoding());
-	/* if pg_do_encoding_conversion didn't strdup, we must */
-	if (result == (char *) utf8string)
+	unicode_to_utf8(c, (unsigned char *) utf8string);
+
+	result = pg_any_to_server(utf8string, strlen(utf8string), PG_UTF8);
+	/* if pg_any_to_server didn't strdup, we must */
+	if (result == utf8string)
 		result = pstrdup(result);
 	return result;
 }