MDEV-31974 Remove global function normalize_db_name()

The function normalize_db_name() fully repeated the functionality
of the class DBNameBuffer. This patch  removes normalize_db_name()
and replaces it to a DBNameBuffer based code.

sql/events.cc

@@ -823,9 +823,6 @@ Events::show_create_event(THD *thd, const LEX_CSTRING *dbname,
 int
 Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
 {
-  const char *db= NULL;
-  int ret;
-  char db_tmp[SAFE_NAME_LEN];
   DBUG_ENTER("Events::fill_schema_events");
 
   /*
@@ -849,11 +846,11 @@ Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
     if (!is_infoschema_db(lexdb) && !is_perfschema_db(lexdb) &&
         check_access(thd, EVENT_ACL, lexdb->str, NULL, NULL, 0, 0))
       DBUG_RETURN(1);
-    db= normalize_db_name(lexdb->str, db_tmp, sizeof(db_tmp));
+    const DBNameBuffer db_tmp(*lexdb, lower_case_table_names);
+    const char *db= db_tmp.to_lex_cstring().str;
+    DBUG_RETURN(db_repository->fill_schema_events(thd, tables, db));
   }
-  ret= db_repository->fill_schema_events(thd, tables, db);
-
-  DBUG_RETURN(ret);
+  DBUG_RETURN(db_repository->fill_schema_events(thd, tables, NULL));
 }
 
 

sql/sql_db.cc

@@ -744,10 +744,9 @@ mysql_create_db_internal(THD *thd, const LEX_CSTRING *db,
     DBUG_RETURN(-1);
   }
 
-  char db_tmp[SAFE_NAME_LEN+1];
-  const char *dbnorm= normalize_db_name(db->str, db_tmp, sizeof(db_tmp));
+  const DBNameBuffer db_tmp(*db, lower_case_table_names);
 
-  if (lock_schema_name(thd, dbnorm))
+  if (lock_schema_name(thd, db_tmp.to_lex_cstring().str))
     DBUG_RETURN(-1);
 
   /* Check directory */
@@ -1047,16 +1046,13 @@ mysql_rm_db_internal(THD *thd, const LEX_CSTRING *db, bool if_exists,
   TABLE_LIST *table;
   DDL_LOG_STATE ddl_log_state;
   Drop_table_error_handler err_handler;
-  LEX_CSTRING rm_db;
-  char db_tmp[SAFE_NAME_LEN+1];
-  const char *dbnorm;
   DBUG_ENTER("mysql_rm_db");
 
-  dbnorm= normalize_db_name(db->str, db_tmp, sizeof(db_tmp));
-  lex_string_set(&rm_db, dbnorm);
+  const DBNameBuffer db_tmp(*db, lower_case_table_names);
+  const LEX_CSTRING rm_db= db_tmp.to_lex_cstring();
   bzero(&ddl_log_state, sizeof(ddl_log_state));
 
-  if (lock_schema_name(thd, dbnorm))
+  if (lock_schema_name(thd, rm_db.str))
     DBUG_RETURN(true);
 
   path_length= build_table_filename(path, sizeof(path) - 1, db->str, "", "", 0);
@@ -1079,7 +1075,7 @@ mysql_rm_db_internal(THD *thd, const LEX_CSTRING *db, bool if_exists,
     }
   }
 
-  if (find_db_tables_and_rm_known_files(thd, dirp, dbnorm, path, &tables))
+  if (find_db_tables_and_rm_known_files(thd, dirp, rm_db.str, path, &tables))
     goto exit;
 
   /*
@@ -1097,7 +1093,7 @@ mysql_rm_db_internal(THD *thd, const LEX_CSTRING *db, bool if_exists,
   /* Lock all tables and stored routines about to be dropped. */
   if (lock_table_names(thd, tables, NULL, thd->variables.lock_wait_timeout,
                        0) ||
-      lock_db_routines(thd, dbnorm))
+      lock_db_routines(thd, rm_db.str))
     goto exit;
 
   if (!rm_mysql_schema)
@@ -2139,14 +2135,3 @@ bool check_db_dir_existence(const char *db_name)
   mysql_rwlock_unlock(&rmdir_lock);
   return ret;
 }
-
-
-const char *normalize_db_name(const char *db, char *buffer, size_t buffer_size)
-{
-  DBUG_ASSERT(buffer_size > 1);
-  if (!lower_case_table_names)
-    return db;
-  strmake(buffer, db, buffer_size - 1);
-  my_casedn_str(system_charset_info, buffer);
-  return buffer;
-}

sql/sql_db.h

@@ -44,9 +44,6 @@ CHARSET_INFO *get_default_db_collation(THD *thd, const char *db_name);
 bool my_dbopt_init(void);
 void my_dbopt_cleanup(void);
 
-const char *normalize_db_name(const char *db, char *buffer,
-                              size_t buffer_size);
-
 void drop_database_objects(THD *thd, const LEX_CSTRING *path,
                            const LEX_CSTRING *db,
                            bool rm_mysql_schema);