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, 6 insertions, 6 deletions

diff --git a/sql/sql_show.h b/sql/sql_show.h
index e93b855450c..dc2fe9738fe 100644
--- a/sql/sql_show.h
+++ b/sql/sql_show.h
@@ -90,8 +90,8 @@ bool mysqld_show_create_get_fields(THD *thd, TABLE_LIST *table_list,
                                    List<Item> *field_list, String *buffer);
 bool mysqld_show_create(THD *thd, TABLE_LIST *table_list);
 void mysqld_show_create_db_get_fields(THD *thd, List<Item> *field_list);
-bool mysqld_show_create_db(THD *thd, LEX_STRING *db_name,
-                           LEX_STRING *orig_db_name,
+bool mysqld_show_create_db(THD *thd, LEX_CSTRING *db_name,
+                           LEX_CSTRING *orig_db_name,
                            const DDL_options_st &options);
 
 void mysqld_list_processes(THD *thd,const char *user,bool verbose);
@@ -103,8 +103,8 @@ bool mysqld_show_contributors(THD *thd);
 bool mysqld_show_privileges(THD *thd);
 char *make_backup_log_name(char *buff, const char *name, const char* log_ext);
 uint calc_sum_of_all_status(STATUS_VAR *to);
-void append_definer(THD *thd, String *buffer, const LEX_STRING *definer_user,
-                    const LEX_STRING *definer_host);
+void append_definer(THD *thd, String *buffer, const LEX_CSTRING *definer_user,
+                    const LEX_CSTRING *definer_host);
 int add_status_vars(SHOW_VAR *list);
 void remove_status_vars(SHOW_VAR *list);
 void init_status_vars();
@@ -180,13 +180,13 @@ typedef struct st_lookup_field_values
     Note that this value length may exceed @c NAME_LEN.
     @sa wild_db_value
   */
-  LEX_STRING db_value;
+  LEX_CSTRING db_value;
   /**
     Value of a TABLE_NAME clause.
     Note that this value length may exceed @c NAME_LEN.
     @sa wild_table_value
   */
-  LEX_STRING table_value;
+  LEX_CSTRING table_value;
   /**
     True when @c db_value is a LIKE clause,
     false when @c db_value is an '=' clause.