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, 4 insertions, 4 deletions

diff --git a/sql/sp_rcontext.cc b/sql/sp_rcontext.cc
index 10329040357..3ceba42b0e4 100644
--- a/sql/sp_rcontext.cc
+++ b/sql/sp_rcontext.cc
@@ -171,7 +171,7 @@ bool sp_rcontext::resolve_type_ref(THD *thd, Column_definition *def,
       !open_tables_only_view_structure(thd, table_list,
                                        thd->mdl_context.has_locks()))
   {
-    if ((src= lex.query_tables->table->find_field_by_name(ref->m_column.str)))
+    if ((src= lex.query_tables->table->find_field_by_name(&ref->m_column)))
     {
       if (!(rc= check_column_grant_for_type_ref(thd, table_list,
                                                 ref->m_column.str,
@@ -237,14 +237,14 @@ bool sp_rcontext::resolve_table_rowtype_ref(THD *thd,
          as the table will be closed and freed soon,
          in the end of this method.
       */
-      LEX_CSTRING tmp= {src[0]->field_name, strlen(src[0]->field_name)};
+      LEX_CSTRING tmp= src[0]->field_name;
       Spvar_definition *def;
       if ((rc= check_column_grant_for_type_ref(thd, table_list,
                                                tmp.str, tmp.length)) ||
-          (rc= !(src[0]->field_name= thd->strmake(tmp.str, tmp.length))) ||
+          (rc= !(src[0]->field_name.str= thd->strmake(tmp.str, tmp.length))) ||
           (rc= !(def= new (thd->mem_root) Spvar_definition(thd, *src))))
         break;
-      src[0]->field_name= tmp.str; // Restore field name, just in case.
+      src[0]->field_name.str= tmp.str; // Restore field name, just in case.
       def->flags&= (uint) ~NOT_NULL_FLAG;
       if ((rc= def->sp_prepare_create_field(thd, thd->mem_root)))
         break;