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, 24 insertions, 14 deletions

diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index b1c797c4ee3..d95240d6d6d 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -1208,9 +1208,8 @@ Field *Item_sum_hybrid::create_tmp_field(bool group, TABLE *table)
   if (args[0]->type() == Item::FIELD_ITEM)
   {
     field= ((Item_field*) args[0])->field;
-
-    if ((field= create_tmp_field_from_field(table->in_use, field, name, table,
-					    NULL)))
+    if ((field= create_tmp_field_from_field(table->in_use, field, &name,
+                                            table, NULL)))
       field->flags&= ~NOT_NULL_FLAG;
     return field;
   }
@@ -1223,18 +1222,25 @@ Field *Item_sum_hybrid::create_tmp_field(bool group, TABLE *table)
   mem_root= table->in_use->mem_root;
   switch (args[0]->field_type()) {
   case MYSQL_TYPE_DATE:
+  {
     field= new (mem_root)
-      Field_newdate(0, maybe_null ? (uchar*)"" : 0, 0, Field::NONE, name);
+      Field_newdate(0, maybe_null ? (uchar*)"" : 0, 0, Field::NONE,
+                    &name);
     break;
+  }
   case MYSQL_TYPE_TIME:
+  {
     field= new_Field_time(mem_root, 0, maybe_null ? (uchar*)"" : 0, 0,
-                          Field::NONE, name, decimals);
+                          Field::NONE, &name, decimals);
     break;
+  }
   case MYSQL_TYPE_TIMESTAMP:
   case MYSQL_TYPE_DATETIME:
+  {
     field= new_Field_datetime(mem_root, 0, maybe_null ? (uchar*)"" : 0, 0,
-                              Field::NONE, name, decimals);
+                              Field::NONE, &name, decimals);
     break;
+  }
   default:
     return Item_sum::create_tmp_field(group, table);
   }
@@ -1676,13 +1682,15 @@ Field *Item_sum_avg::create_tmp_field(bool group, TABLE *table)
     field= new (mem_root)
       Field_string(((Item_sum_avg::result_type() == DECIMAL_RESULT) ?
                     dec_bin_size : sizeof(double)) + sizeof(longlong),
-                   0, name, &my_charset_bin);
+                   0, &name, &my_charset_bin);
   }
   else if (Item_sum_avg::result_type() == DECIMAL_RESULT)
     field= Field_new_decimal::create_from_item(mem_root, this);
   else
-    field= new (mem_root) Field_double(max_length, maybe_null, name, decimals,
-                                       TRUE);
+  {
+    field= new (mem_root) Field_double(max_length, maybe_null, &name,
+                                       decimals, TRUE);
+  }
   if (field)
     field->init(table);
   return field;
@@ -1910,10 +1918,12 @@ Field *Item_sum_variance::create_tmp_field(bool group, TABLE *table)
       The easiest way is to do this is to store both value in a string
       and unpack on access.
     */
-    field= new Field_string(sizeof(double)*2 + sizeof(longlong), 0, name, &my_charset_bin);
+    field= new Field_string(sizeof(double)*2 + sizeof(longlong), 0,
+                            &name, &my_charset_bin);
   }
   else
-    field= new Field_double(max_length, maybe_null, name, decimals, TRUE);
+    field= new Field_double(max_length, maybe_null, &name, decimals,
+                            TRUE);
 
   if (field != NULL)
     field->init(table);
@@ -3356,13 +3366,13 @@ Field *Item_func_group_concat::make_string_field(TABLE *table_arg)
 {
   Field *field;
   DBUG_ASSERT(collation.collation);
+
   if (too_big_for_varchar())
     field= new Field_blob(max_length,
-                          maybe_null, name, collation.collation, TRUE);
+                          maybe_null, &name, collation.collation, TRUE);
   else
     field= new Field_varstring(max_length,
-                               maybe_null, name, table_arg->s,
-                               collation.collation);
+                               maybe_null, &name, table_arg->s, collation.collation);
 
   if (field)
     field->init(table_arg);