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, 8 insertions, 8 deletions

diff --git a/sql/sql_load.cc b/sql/sql_load.cc
index 6f0e97a61c9..b430aea4c0b 100644
--- a/sql/sql_load.cc
+++ b/sql/sql_load.cc
@@ -283,13 +283,13 @@ int mysql_load(THD *thd,sql_exchange *ex,TABLE_LIST *table_list,
   killed_state killed_status;
   bool is_concurrent;
 #endif
-  char *db = table_list->db;			// This is never null
+  const char *db = table_list->db;		// This is never null
   /*
     If path for file is not defined, we will use the current database.
     If this is not set, we will use the directory where the table to be
     loaded is located
   */
-  char *tdb= thd->db ? thd->db : db;		// Result is never null
+  const char *tdb= thd->db ? thd->db : db;	// Result is never null
   ulong skip_lines= ex->skip_lines;
   bool transactional_table __attribute__((unused));
   DBUG_ENTER("mysql_load");
@@ -812,7 +812,7 @@ static bool write_execute_load_query_log_event(THD *thd, sql_exchange* ex,
       if (n++)
         query_str.append(", ");
       if (item->real_type() == Item::FIELD_ITEM)
-        append_identifier(thd, &query_str, item->name, strlen(item->name));
+        append_identifier(thd, &query_str, item->name.str, item->name.length);
       else
       {
         /* Actually Item_user_var_as_out_param despite claiming STRING_ITEM. */
@@ -836,8 +836,8 @@ static bool write_execute_load_query_log_event(THD *thd, sql_exchange* ex,
       val= lv++;
       if (n++)
         query_str.append(STRING_WITH_LEN(", "));
-      append_identifier(thd, &query_str, item->name, strlen(item->name));
-      query_str.append(val->name);
+      append_identifier(thd, &query_str, item->name.str, item->name.length);
+      query_str.append(val->name.str, val->name.length);
     }
   }
 
@@ -1085,7 +1085,7 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
           Field *field= ((Item_field *)real_item)->field;
           if (field->reset())
           {
-            my_error(ER_WARN_NULL_TO_NOTNULL, MYF(0), field->field_name,
+            my_error(ER_WARN_NULL_TO_NOTNULL, MYF(0), field->field_name.str,
                      thd->get_stmt_da()->current_row_for_warning());
             DBUG_RETURN(1);
           }
@@ -1164,7 +1164,7 @@ read_sep_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
           Field *field= ((Item_field *)real_item)->field;
           if (field->reset())
           {
-            my_error(ER_WARN_NULL_TO_NOTNULL, MYF(0),field->field_name,
+            my_error(ER_WARN_NULL_TO_NOTNULL, MYF(0),field->field_name.str,
                      thd->get_stmt_da()->current_row_for_warning());
             DBUG_RETURN(1);
           }
@@ -1296,7 +1296,7 @@ read_xml_field(THD *thd, COPY_INFO &info, TABLE_LIST *table_list,
       xmlit.rewind();
       tag= xmlit++;
       
-      while(tag && strcmp(tag->field.c_ptr(), item->name) != 0)
+      while(tag && strcmp(tag->field.c_ptr(), item->name.str) != 0)
         tag= xmlit++;
       
       if (!tag) // found null