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, 5 insertions, 4 deletions

diff --git a/sql/strfunc.h b/sql/strfunc.h
index 7b031710c76..7f3021e1a6d 100644
--- a/sql/strfunc.h
+++ b/sql/strfunc.h
@@ -33,12 +33,13 @@ uint find_type2(const TYPELIB *lib, const char *find, uint length,
 void unhex_type2(TYPELIB *lib);
 uint check_word(TYPELIB *lib, const char *val, const char *end,
 		const char **end_of_word);
-int find_string_in_array(LEX_STRING * const haystack, LEX_STRING * const needle,
+int find_string_in_array(LEX_CSTRING * const haystack,
+                         LEX_CSTRING * const needle,
                          CHARSET_INFO * const cs);
-char *flagset_to_string(THD *thd, LEX_STRING *result, ulonglong set,
+const char *flagset_to_string(THD *thd, LEX_CSTRING *result, ulonglong set,
                         const char *lib[]);
-char *set_to_string(THD *thd, LEX_STRING *result, ulonglong set,
-                    const char *lib[]);
+const char *set_to_string(THD *thd, LEX_CSTRING *result, ulonglong set,
+                          const char *lib[]);
 
 /*
   These functions were protected by INNODB_COMPATIBILITY_HOOKS