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, 10 insertions, 9 deletions

diff --git a/sql/unireg.cc b/sql/unireg.cc
index 0bb8a4e77c6..268ee24f509 100644
--- a/sql/unireg.cc
+++ b/sql/unireg.cc
@@ -73,7 +73,7 @@ static uchar *extra2_write_len(uchar *pos, size_t len)
 }
 
 static uchar *extra2_write(uchar *pos, enum extra2_frm_value_type type,
-                           LEX_STRING *str)
+                           const LEX_CSTRING *str)
 {
   *pos++ = type;
   pos= extra2_write_len(pos, str->length);
@@ -84,7 +84,7 @@ static uchar *extra2_write(uchar *pos, enum extra2_frm_value_type type,
 static uchar *extra2_write(uchar *pos, enum extra2_frm_value_type type,
                            LEX_CUSTRING *str)
 {
-  return extra2_write(pos, type, reinterpret_cast<LEX_STRING *>(str));
+  return extra2_write(pos, type, reinterpret_cast<LEX_CSTRING *>(str));
 }
 
 /**
@@ -107,7 +107,7 @@ LEX_CUSTRING build_frm_image(THD *thd, const char *table,
                               List<Create_field> &create_fields,
                               uint keys, KEY *key_info, handler *db_file)
 {
-  LEX_STRING str_db_type;
+  LEX_CSTRING str_db_type;
   uint reclength, key_info_length, i;
   ulong key_buff_length;
   ulong filepos, data_offset;
@@ -616,7 +616,8 @@ static bool pack_header(THD *thd, uchar *forminfo,
   while ((field=it++))
   {
     if (validate_comment_length(thd, &field->comment, COLUMN_COMMENT_MAXLEN,
-                                ER_TOO_LONG_FIELD_COMMENT, field->field_name))
+                                ER_TOO_LONG_FIELD_COMMENT,
+                                field->field_name.str))
        DBUG_RETURN(1);
 
     totlength+= field->length;
@@ -632,7 +633,7 @@ static bool pack_header(THD *thd, uchar *forminfo,
     length=field->pack_length;
     if ((uint) field->offset+ (uint) data_offset+ length > reclength)
       reclength=(uint) (field->offset+ data_offset + length);
-    n_length+= (ulong) strlen(field->field_name)+1;
+    n_length+= field->field_name.length + 1;
     field->interval_id=0;
     field->save_interval= 0;
     if (field->interval)
@@ -776,7 +777,7 @@ static size_t packed_fields_length(List<Create_field> &create_fields)
     }
 
     length+= FCOMP;
-    length+= strlen(field->field_name)+1;
+    length+= field->field_name.length + 1;
     length+= field->comment.length;
   }
   length+= 2;
@@ -837,7 +838,7 @@ static bool pack_fields(uchar **buff_arg, List<Create_field> &create_fields,
   it.rewind();
   while ((field=it++))
   {
-    buff= (uchar*)strmov((char*) buff, field->field_name);
+    buff= (uchar*)strmov((char*) buff, field->field_name.str);
     *buff++=NAMES_SEP_CHAR;
   }
   *buff++= 0;
@@ -959,7 +960,7 @@ static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
                                 field->unireg_check,
                                 field->save_interval ? field->save_interval
                                                      : field->interval,
-                                field->field_name);
+                                &field->field_name);
     if (!regfield)
     {
       error= 1;
@@ -989,7 +990,7 @@ static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
       /* If not ok or warning of level 'note' */
       if (res != 0 && res != 3)
       {
-        my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name);
+        my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name.str);
         error= 1;
         delete regfield; //To avoid memory leak
         goto err;