Changing field::field_name and Item::name to LEX_CSTRING

Benefits of this patch:
- Removed a lot of calls to strlen(), especially for field_string
- Strings generated by parser are now const strings, less chance of
  accidently changing a string
- Removed a lot of calls with LEX_STRING as parameter (changed to pointer)
- More uniform code
- Item::name_length was not kept up to date. Now fixed
- Several bugs found and fixed (Access to null pointers,
  access of freed memory, wrong arguments to printf like functions)
- Removed a lot of casts from (const char*) to (char*)

Changes:
- This caused some ABI changes
  - lex_string_set now uses LEX_CSTRING
  - Some fucntions are now taking const char* instead of char*
- Create_field::change and after changed to LEX_CSTRING
- handler::connect_string, comment and engine_name() changed to LEX_CSTRING
- Checked printf() related calls to find bugs. Found and fixed several
  errors in old code.
- A lot of changes from LEX_STRING to LEX_CSTRING, especially related to
  parsing and events.
- Some changes from LEX_STRING and LEX_STRING & to LEX_CSTRING*
- Some changes for char* to const char*
- Added printf argument checking for my_snprintf()
- Introduced null_clex_str, star_clex_string, temp_lex_str to simplify
  code
- Added item_empty_name and item_used_name to be able to distingush between
  items that was given an empty name and items that was not given a name
  This is used in sql_yacc.yy to know when to give an item a name.
- select table_name."*' is not anymore same as table_name.*
- removed not used function Item::rename()
- Added comparision of item->name_length before some calls to
  my_strcasecmp() to speed up comparison
- Moved Item_sp_variable::make_field() from item.h to item.cc
- Some minimal code changes to avoid copying to const char *
- Fixed wrong error message in wsrep_mysql_parse()
- Fixed wrong code in find_field_in_natural_join() where real_item() was
  set when it shouldn't
- ER_ERROR_ON_RENAME was used with extra arguments.
- Removed some (wrong) ER_OUTOFMEMORY, as alloc_root will already
  give the error.

TODO:
- Check possible unsafe casts in plugin/auth_examples/qa_auth_interface.c
- Change code to not modify LEX_CSTRING for database name
  (as part of lower_case_table_names)

1 files changed, 7 insertions, 5 deletions

diff --git a/libmysqld/lib_sql.cc b/libmysqld/lib_sql.cc
index 555eadc9425..5883061f24f 100644
--- a/libmysqld/lib_sql.cc
+++ b/libmysqld/lib_sql.cc
@@ -742,7 +742,7 @@ emb_transfer_connect_attrs(MYSQL *mysql)
 int check_embedded_connection(MYSQL *mysql, const char *db)
 {
   int result;
-  LEX_STRING db_str = { (char*)db, db ? strlen(db) : 0 };
+  LEX_CSTRING db_str = { db, safe_strlen(db) };
   THD *thd= (THD*)mysql->thd;
 
   /* the server does the same as the client */
@@ -1046,12 +1046,14 @@ bool Protocol::send_result_set_metadata(List<Item> *list, uint flags)
                                   strlen(server_field.db_name), cs, thd_cs);
     client_field->table= dup_str_aux(field_alloc, server_field.table_name,
                                      strlen(server_field.table_name), cs, thd_cs);
-    client_field->name= dup_str_aux(field_alloc, server_field.col_name,
-                                    strlen(server_field.col_name), cs, thd_cs);
+    client_field->name= dup_str_aux(field_alloc, server_field.col_name.str,
+                                    server_field.col_name.length, cs, thd_cs);
     client_field->org_table= dup_str_aux(field_alloc, server_field.org_table_name,
                                          strlen(server_field.org_table_name), cs, thd_cs);
-    client_field->org_name= dup_str_aux(field_alloc, server_field.org_col_name,
-                                        strlen(server_field.org_col_name), cs, thd_cs);
+    client_field->org_name= dup_str_aux(field_alloc,
+                                        server_field.org_col_name.str,
+                                        server_field.org_col_name.length,
+                                        cs, thd_cs);
     if (item->charset_for_protocol() == &my_charset_bin || thd_cs == NULL)
     {
       /* No conversion */