Simplify fn_rext

- Change interface according to real usage
- Fix comment
- Rename to fn_frm_ext

sql/ha_partition.cc

@@ -685,7 +685,7 @@ int ha_partition::create(const char *name, TABLE *table_arg,
   handler **file, **abort_file;
   DBUG_ENTER("ha_partition::create");
 
-  DBUG_ASSERT(*fn_rext((char*)name) == '\0');
+  DBUG_ASSERT(!fn_frm_ext(name));
 
   /* Not allowed to create temporary partitioned tables */
   if (create_info && create_info->tmp_table())

sql/sql_db.cc

@@ -1725,8 +1725,7 @@ bool mysql_upgrade_db(THD *thd, LEX_CSTRING *old_db)
       DBUG_PRINT("info",("Examining: %s", file->name));
 
       /* skiping non-FRM files */
-      if (my_strcasecmp(files_charset_info,
-                        (extension= fn_rext(file->name)), reg_ext))
+      if (!(extension= (char*) fn_frm_ext(file->name)))
         continue;
 
       /* A frm file found, add the table info rename list */

sql/table.cc

@@ -217,31 +217,26 @@ static uchar *get_field_name(Field **buff, size_t *length,
   Returns pointer to '.frm' extension of the file name.
 
   SYNOPSIS
-    fn_rext()
+    fn_frm_ext()
     name       file name
 
   DESCRIPTION
     Checks file name part starting with the rightmost '.' character,
     and returns it if it is equal to '.frm'. 
 
-  TODO
-    It is a good idea to get rid of this function modifying the code
-    to garantee that the functions presently calling fn_rext() always
-    get arguments in the same format: either with '.frm' or without '.frm'.
-
   RETURN VALUES
-    Pointer to the '.frm' extension. If there is no extension,
-    or extension is not '.frm', pointer at the end of file name.
+    Pointer to the '.frm' extension or NULL if not a .frm file
 */
 
-char *fn_rext(char *name)
+const char *fn_frm_ext(const char *name)
 {
-  char *res= strrchr(name, '.');
+  const char *res= strrchr(name, '.');
   if (res && !strcmp(res, reg_ext))
     return res;
-  return name + strlen(name);
+  return 0;
 }
 
+
 TABLE_CATEGORY get_table_category(const LEX_CSTRING *db,
                                   const LEX_CSTRING *name)
 {

sql/table.h

@@ -2702,7 +2702,7 @@ ulong get_form_pos(File file, uchar *head, TYPELIB *save_names);
 void append_unescaped(String *res, const char *pos, uint length);
 void prepare_frm_header(THD *thd, uint reclength, uchar *fileinfo,
                         HA_CREATE_INFO *create_info, uint keys, KEY *key_info);
-char *fn_rext(char *name);
+const char *fn_frm_ext(const char *name);
 
 /* Check that the integer is in the internal */
 static inline int set_zone(int nr,int min_zone,int max_zone)