Split item->flags into base_flags and with_flags

This was done to simplify copying of with_* flags

Other things:
- Changed Flags to C++ enums, which enables gdb to print
  out bit values for the flags. This also enables compiler
  errors if one tries to manipulate a non existing bit in
  a variable.
- Added set_maybe_null() as a shortcut as setting the
  MAYBE_NULL flags was used in a LOT of places.
- Renamed PARAM flag to SP_VAR to ensure it's not confused with persistent
  statement parameters.

Author: montywi

plugin/func_test/plugin.cc

@@ -32,7 +32,7 @@ class Item_func_sysconst_test :public Item_func_sysconst
   bool fix_length_and_dec()
   {
     max_length= MAX_FIELD_NAME * system_charset_info->mbmaxlen;
-    flags|= ITEM_FLAG_MAYBE_NULL;
+    set_maybe_null();
     return false;
   }
   const char *func_name() const { return "sysconst_test"; }

plugin/type_inet/item_inetfunc.h

@@ -37,7 +37,7 @@ class Item_func_inet_aton : public Item_longlong_func
   {
     decimals= 0;
     max_length= 21;
-    flags|= ITEM_FLAG_MAYBE_NULL;
+    set_maybe_null();
     unsigned_flag= 1;
     return FALSE;
   }
@@ -61,7 +61,7 @@ class Item_func_inet_ntoa : public Item_str_func
   {
     decimals= 0;
     fix_length_and_charset(3 * 8 + 7, default_charset());
-    flags|= ITEM_FLAG_MAYBE_NULL;
+    set_maybe_null();
     return FALSE;
   }
   Item *get_copy(THD *thd)
@@ -105,7 +105,7 @@ class Item_func_inet6_aton : public Item_str_func
   {
     decimals= 0;
     fix_length_and_charset(16, &my_charset_bin);
-    flags|= ITEM_FLAG_MAYBE_NULL;
+    set_maybe_null();
     return FALSE;
   }
   Item *get_copy(THD *thd)
@@ -139,7 +139,7 @@ class Item_func_inet6_ntoa : public Item_str_ascii_func
     // 4 symbols per group
     fix_length_and_charset(8 * 4 + 7, default_charset());
 
-    flags|= ITEM_FLAG_MAYBE_NULL;;
+    set_maybe_null();;
     return FALSE;
   }
   String *val_str_ascii(String *to);

plugin/type_inet/sql_type_inet.cc

@@ -1055,7 +1055,7 @@ class Item_typecast_inet6: public Item_func
   {
     Type_std_attributes::operator=(Type_std_attributes_inet6());
     if (Inet6::fix_fields_maybe_null_on_conversion_to_inet6(args[0]))
-      flags|= ITEM_FLAG_MAYBE_NULL;
+      set_maybe_null();
     return false;
   }
   String *val_str(String *to) override

sql/item.cc

@@ -413,7 +413,8 @@ Item::Item(THD *thd):
   name(null_clex_str), orig_name(0), is_expensive_cache(-1)
 {
   DBUG_ASSERT(thd);
-  flags= ITEM_FLAG_FIXED | ITEM_FLAG_IS_AUTOGENERATED_NAME;
+  base_flags= item_base_t::FIXED | item_base_t::IS_AUTOGENERATED_NAME;
+  with_flags= item_with_t::NONE;
   null_value= 0;
   marker= 0;
 
@@ -445,7 +446,8 @@ Item::Item():
   name(null_clex_str), orig_name(0), is_expensive_cache(-1)
 {
   DBUG_ASSERT(my_progname == NULL); // before main()
-  flags= ITEM_FLAG_FIXED | ITEM_FLAG_IS_AUTOGENERATED_NAME;
+  base_flags= item_base_t::FIXED | item_base_t::IS_AUTOGENERATED_NAME;
+  with_flags= item_with_t::NONE;
   null_value= 0;
   marker= 0;
   join_tab_idx= MAX_TABLES;
@@ -473,13 +475,13 @@ Item::Item(THD *thd, Item *item):
   str_value(item->str_value),
   name(item->name),
   orig_name(item->orig_name),
+  base_flags(item->base_flags & ~item_base_t::FIXED),
+  with_flags(item->with_flags),
   marker(item->marker),
   null_value(item->null_value),
   is_expensive_cache(-1),
   join_tab_idx(item->join_tab_idx)
 {
-  flags= item->flags & (item_flags_t) ~ITEM_FLAG_FIXED;
-
   next= thd->free_list;				// Put in free list
   thd->free_list= this;
 }
@@ -1599,9 +1601,10 @@ bool Item_sp_variable::fix_fields_from_item(THD *thd, Item **, const Item *it)
   max_length= it->max_length;
   decimals= it->decimals;
   unsigned_flag= it->unsigned_flag;
-  flags|= ITEM_FLAG_WITH_PARAM | ITEM_FLAG_FIXED;
+  base_flags|= item_base_t::FIXED;
+  with_flags|= item_with_t::SP_VAR;
   if (thd->lex->current_select && thd->lex->current_select->master_unit()->item)
-    thd->lex->current_select->master_unit()->item->flags|= ITEM_FLAG_WITH_PARAM;
+    thd->lex->current_select->master_unit()->item->with_flags|= item_with_t::SP_VAR;
   collation.set(it->collation.collation, it->collation.derivation);
 
   return FALSE;
@@ -1723,7 +1726,7 @@ Item_splocal::Item_splocal(THD *thd,
   m_var_idx(sp_var_idx),
   m_type(handler == &type_handler_row ? ROW_ITEM : CONST_ITEM)
 {
-  flags|= ITEM_FLAG_MAYBE_NULL;
+  set_maybe_null();
 }
 
 
@@ -2086,7 +2089,7 @@ Item_name_const::Item_name_const(THD *thd, Item *name_arg, Item *val):
   StringBuffer<128> name_buffer;
   String *name_str;
 
-  flags|= ITEM_FLAG_MAYBE_NULL;
+  set_maybe_null();
   if (name_item->basic_const_item() &&
       (name_str= name_item->val_str(&name_buffer))) // Can't have a NULL name
     set_name(thd, name_str);
@@ -2140,7 +2143,7 @@ bool Item_name_const::fix_fields(THD *thd, Item **ref)
   max_length= value_item->max_length;
   decimals= value_item->decimals;
   unsigned_flag= value_item->unsigned_flag;
-  flags|= ITEM_FLAG_FIXED;
+  base_flags|= item_base_t::FIXED;
   return FALSE;
 }
 
@@ -2959,7 +2962,7 @@ Item_field::Item_field(THD *thd, Field *f)
   */
   orig_table_name= table_name;
   orig_field_name= field_name;
-  flags|= ITEM_FLAG_WITH_FIELD;
+  with_flags|= item_with_t::FIELD;
 }
 
 
@@ -3009,7 +3012,7 @@ Item_field::Item_field(THD *thd, Name_resolution_context *context_arg,
     name= orig_field_name;
   }
   set_field(f);
-  flags|= ITEM_FLAG_WITH_FIELD;
+  with_flags|= item_with_t::FIELD;
 }
 
 
@@ -3025,7 +3028,7 @@ Item_field::Item_field(THD *thd, Name_resolution_context *context_arg,
   collation.set(DERIVATION_IMPLICIT);
   if (select && select->parsing_place != IN_HAVING)
       select->select_n_where_fields++;
-  flags|= ITEM_FLAG_WITH_FIELD;
+  with_flags|= item_with_t::FIELD;
 }
 
 /**
@@ -3040,7 +3043,7 @@ Item_field::Item_field(THD *thd, Item_field *item)
    any_privileges(item->any_privileges)
 {
   collation.set(DERIVATION_IMPLICIT);
-  flags|= ITEM_FLAG_WITH_FIELD;
+  with_flags|= item_with_t::FIELD;
 }
 
 
@@ -3065,7 +3068,7 @@ void Item_field::set_field(Field *field_par)
   db_name= field_par->table->s->db;
   alias_name_used= field_par->table->alias_name_used;
 
-  flags|= ITEM_FLAG_FIXED;
+  base_flags|= item_base_t::FIXED;
   if (field->table->s->tmp_table == SYSTEM_TMP_TABLE)
     any_privileges= 0;
 }
@@ -3959,7 +3962,7 @@ Item_param::Item_param(THD *thd, const LEX_CSTRING *name_arg,
     before mysql_stmt_execute(), so we assuming that it can be NULL until
     value is set.
   */
-  flags|= ITEM_FLAG_MAYBE_NULL;
+  set_maybe_null();
 }
 
 
@@ -3991,7 +3994,7 @@ void Item_param::sync_clones()
   {
     Item_param *c= *c_ptr;
     /* Scalar-type members: */
-    c->copy_flags(this, ITEM_FLAG_MAYBE_NULL);
+    c->copy_flags(this, item_base_t::MAYBE_NULL);
     c->null_value= null_value;
     c->Type_std_attributes::operator=(*this);
     c->Type_handler_hybrid_field_type::operator=(*this);
@@ -4043,7 +4046,7 @@ void Item_param::set_int(longlong i, uint32 max_length_arg)
   collation= DTCollation_numeric();
   max_length= max_length_arg;
   decimals= 0;
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
   DBUG_VOID_RETURN;
 }
@@ -4057,7 +4060,7 @@ void Item_param::set_double(double d)
   collation= DTCollation_numeric();
   max_length= DBL_DIG + 8;
   decimals= NOT_FIXED_DEC;
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
   DBUG_VOID_RETURN;
 }
@@ -4089,7 +4092,7 @@ void Item_param::set_decimal(const char *str, ulong length)
   max_length=
     my_decimal_precision_to_length_no_truncation(value.m_decimal.precision(),
                                                  decimals, unsigned_flag);
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
   DBUG_VOID_RETURN;
 }
@@ -4106,7 +4109,7 @@ void Item_param::set_decimal(const my_decimal *dv, bool unsigned_arg)
   unsigned_flag= unsigned_arg;
   max_length= my_decimal_precision_to_length(value.m_decimal.intg + decimals,
                                              decimals, unsigned_flag);
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
 }
 
@@ -4117,7 +4120,7 @@ void Item_param::fix_temporal(uint32 max_length_arg, uint decimals_arg)
   collation= DTCollation_numeric();
   max_length= max_length_arg;
   decimals= decimals_arg;
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
 }
 
@@ -4127,7 +4130,7 @@ void Item_param::set_time(const MYSQL_TIME *tm,
 {
   DBUG_ASSERT(value.type_handler()->cmp_type() == TIME_RESULT);
   value.time= *tm;
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
   fix_temporal(max_length_arg, decimals_arg);
 }
@@ -4162,7 +4165,7 @@ void Item_param::set_time(MYSQL_TIME *tm, timestamp_type time_type,
                                  &str, time_type, NULL, NULL, NULL);
     set_zero_time(&value.time, time_type);
   }
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
   fix_temporal(max_length_arg,
                tm->second_part > 0 ? TIME_SECOND_PART_DIGITS : 0);
@@ -4199,7 +4202,7 @@ bool Item_param::set_str(const char *str, ulong length,
   state= SHORT_DATA_VALUE;
   collation.set(tocs, DERIVATION_COERCIBLE);
   max_length= length;
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
   /* max_length and decimals are set after charset conversion */
   /* sic: str may be not null-terminated, don't add DBUG_PRINT here */
@@ -4234,7 +4237,7 @@ bool Item_param::set_longdata(const char *str, ulong length)
   if (value.m_string.append(str, length, &my_charset_bin))
     DBUG_RETURN(TRUE);
   state= LONG_DATA_VALUE;
-  flags&= (item_flags_t) ~ITEM_FLAG_MAYBE_NULL;
+  base_flags&= ~item_base_t::MAYBE_NULL;
   null_value= 0;
 
   DBUG_RETURN(FALSE);
@@ -4335,7 +4338,7 @@ void Item_param::reset()
   value.m_string.set_charset(&my_charset_bin);
   collation.set(&my_charset_bin, DERIVATION_COERCIBLE);
   state= NO_VALUE;
-  flags|= ITEM_FLAG_MAYBE_NULL;
+  set_maybe_null();
   null_value= 0;
   DBUG_VOID_RETURN;
 }
@@ -4794,7 +4797,7 @@ Item_param::set_param_type_and_swap_value(Item_param *src)
   Type_std_attributes::set(src);
   set_handler(src->type_handler());
 
-  copy_flags(src, ITEM_FLAG_MAYBE_NULL);
+  copy_flags(src, item_base_t::MAYBE_NULL);
   null_value= src->null_value;
   state= src->state;
 
@@ -5629,7 +5632,7 @@ Item_field::fix_outer_field(THD *thd, Field **from_field, Item **reference)
             set_if_bigger(thd->lex->in_sum_func->max_arg_level,
                           select->nest_level);
             set_field(*from_field);
-            flags|= ITEM_FLAG_FIXED;
+            base_flags|= item_base_t::FIXED;
             mark_as_dependent(thd, last_checked_context->select_lex,
                               context->select_lex, this,
                               ((ref_type == REF_ITEM ||
@@ -6049,7 +6052,7 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
     }
   }
 #endif
-  flags|= ITEM_FLAG_FIXED;
+  base_flags|= item_base_t::FIXED;
   if (field->vcol_info)
     fix_session_vcol_expr_for_read(thd, field, field->vcol_info);
   if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY &&
@@ -8072,20 +8075,10 @@ void Item_ref::set_properties()
     We have to remember if we refer to a sum function, to ensure that
     split_sum_func() doesn't try to change the reference.
   */
-  /* Reset flags if called from update_ref() */
-  flags&= ~ (ITEM_FLAG_WITH_SUM_FUNC |
-             ITEM_FLAG_WITH_PARAM |
-             ITEM_FLAG_WITH_WINDOW_FUNC |
-             ITEM_FLAG_WITH_SUBQUERY |
-             ITEM_FLAG_WITH_FIELD);
-
-  flags|= (ITEM_FLAG_FIXED |
-           ((*ref)->flags & (ITEM_FLAG_MAYBE_NULL |
-                             ITEM_FLAG_WITH_SUM_FUNC |
-                             ITEM_FLAG_WITH_PARAM |
-                             ITEM_FLAG_WITH_WINDOW_FUNC |
-                             ITEM_FLAG_WITH_SUBQUERY |
-                             ITEM_FLAG_WITH_FIELD)));
+  with_flags= (*ref)->with_flags;
+  base_flags|= (item_base_t::FIXED |
+                ((*ref)->base_flags & item_base_t::MAYBE_NULL));
+
   if (alias_name_used)
     return;
   if ((*ref)->type() == FIELD_ITEM)
@@ -8563,14 +8556,10 @@ Item_cache_wrapper::Item_cache_wrapper(THD *thd, Item *item_arg):
   DBUG_ASSERT(orig_item->fixed());
   Type_std_attributes::set(orig_item);
 
-  flags|= ITEM_FLAG_FIXED |
-    (orig_item->flags &
-           (ITEM_FLAG_MAYBE_NULL |
-            ITEM_FLAG_WITH_SUM_FUNC |
-            ITEM_FLAG_WITH_SUBQUERY |
-            ITEM_FLAG_WITH_PARAM |
-            ITEM_FLAG_WITH_FIELD));
-  
+  base_flags|= (item_base_t::FIXED |
+                (orig_item->base_flags & item_base_t::MAYBE_NULL));
+  with_flags|= orig_item->with_flags;
+
   name= item_arg->name;
 
   if ((expr_value= orig_item->get_cache(thd)))
@@ -9029,7 +9018,7 @@ bool Item_direct_view_ref::fix_fields(THD *thd, Item **reference)
   if (Item_direct_ref::fix_fields(thd, reference))
     return TRUE;
   if (view->table && view->table->maybe_null)
-    flags|= ITEM_FLAG_MAYBE_NULL;
+    set_maybe_null();
   set_null_ref_table();
   return FALSE;
 }
@@ -9789,7 +9778,7 @@ bool Item_trigger_field::fix_fields(THD *thd, Item **items)
     field= (row_version == OLD_ROW) ? triggers->old_field[field_idx] :
                                       triggers->new_field[field_idx];
     set_field(field);
-    flags|= ITEM_FLAG_FIXED;
+    base_flags|= item_base_t::FIXED;
     return FALSE;
   }