MDEV-16861 Split Item::update_null_value() into a new virtual method in Type_handler

7 files changed, 68 insertions, 49 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 2b325706d4c..f0020543aec 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -276,13 +276,6 @@ bool Item::get_temporal_with_sql_mode(MYSQL_TIME *ltime)
 }
 
 
-bool Item::is_null_from_temporal()
-{
-  MYSQL_TIME ltime;
-  return get_temporal_with_sql_mode(&ltime);
-}
-
-
 longlong Item::val_int_from_str(int *error)
 {
   char buff[MAX_FIELD_WIDTH];
@@ -7488,7 +7481,7 @@ void Item_field::update_null_value()
 
   no_errors= thd->no_errors;
   thd->no_errors= 1;
-  Item::update_null_value();
+  type_handler()->Item_update_null_value(this);
   thd->no_errors= no_errors;
 }
 
diff --git a/sql/item.h b/sql/item.h
index 21a96760c49..cf9e8cd922c 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -1398,8 +1398,6 @@ public:
 
   // Get TIME, DATE or DATETIME using proper sql_mode flags for the field type
   bool get_temporal_with_sql_mode(MYSQL_TIME *ltime);
-  // Check NULL value for a TIME, DATE or DATETIME expression
-  bool is_null_from_temporal();
 
   int save_time_in_field(Field *field, bool no_conversions);
   int save_date_in_field(Field *field, bool no_conversions);
@@ -1699,35 +1697,7 @@ public:
   */
   virtual void update_null_value ()
   {
-    switch (cmp_type()) {
-    case INT_RESULT:
-      (void) val_int();
-      break;
-    case REAL_RESULT:
-      (void) val_real();
-      break;
-    case DECIMAL_RESULT:
-      {
-        my_decimal tmp;
-        (void) val_decimal(&tmp);
-      }
-      break;
-    case TIME_RESULT:
-      {
-        MYSQL_TIME ltime;
-        (void) get_temporal_with_sql_mode(&ltime);
-      }
-      break;
-    case STRING_RESULT:
-      {
-        StringBuffer<MAX_FIELD_WIDTH> tmp;
-        (void) val_str(&tmp);
-      }
-      break;
-    case ROW_RESULT:
-      DBUG_ASSERT(0);
-      null_value= true;
-    }
+    return type_handler()->Item_update_null_value(this);
   }
 
   /*
@@ -4653,8 +4623,6 @@ public:
   }
 
   const MYSQL_TIME *const_ptr_mysql_time() const { return &cached_time; }
-  bool is_null()
-  { return is_null_from_temporal(); }
   bool get_date_with_sql_mode(MYSQL_TIME *to);
   String *val_str(String *str)
   { return val_string_from_date(str); }
diff --git a/sql/item_func.cc b/sql/item_func.cc
index 931e621529e..1f4d60b9c6c 100644
--- a/sql/item_func.cc
+++ b/sql/item_func.cc
@@ -5632,7 +5632,7 @@ void Item_func_get_system_var::update_null_value()
   THD *thd= current_thd;
   int save_no_errors= thd->no_errors;
   thd->no_errors= TRUE;
-  Item::update_null_value();
+  type_handler()->Item_update_null_value(this);
   thd->no_errors= save_no_errors;
 }
 
diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index 29af0b43d9d..7c4ab93dc80 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -67,11 +67,6 @@ public:
   const Type_handler *type_handler() const { return string_type_handler(); }
   void left_right_max_length();
   bool fix_fields(THD *thd, Item **ref);
-  void update_null_value()
-  {
-    StringBuffer<MAX_FIELD_WIDTH> tmp;
-    (void) val_str(&tmp);
-  }
 };
 
 
diff --git a/sql/item_subselect.h b/sql/item_subselect.h
index 084abf787af..4980709b979 100644
--- a/sql/item_subselect.h
+++ b/sql/item_subselect.h
@@ -399,7 +399,7 @@ public:
   }
   void no_rows_in_result();
 
-  const Type_handler *type_handler() const { return &type_handler_longlong; }
+  const Type_handler *type_handler() const { return &type_handler_bool; }
   longlong val_int();
   double val_real();
   String *val_str(String*);
@@ -627,7 +627,6 @@ public:
   double val_real();
   String *val_str(String*);
   my_decimal *val_decimal(my_decimal *);
-  void update_null_value () { (void) val_bool(); }
   bool val_bool();
   bool test_limit(st_select_lex_unit *unit);
   void print(String *str, enum_query_type query_type);
diff --git a/sql/sql_type.cc b/sql/sql_type.cc
index 924f077a76c..436778fb32f 100644
--- a/sql/sql_type.cc
+++ b/sql/sql_type.cc
@@ -2619,6 +2619,61 @@ uint32 Type_handler_general_purpose_int::max_display_length(const Item *item)
 
 /*************************************************************************/
 
+void Type_handler_row::Item_update_null_value(Item *item) const
+{
+  DBUG_ASSERT(0);
+  item->null_value= true;
+}
+
+
+void Type_handler_time_common::Item_update_null_value(Item *item) const
+{
+  MYSQL_TIME ltime;
+  (void) item->get_date(&ltime, TIME_TIME_ONLY);
+}
+
+
+void Type_handler_temporal_with_date::Item_update_null_value(Item *item) const
+{
+  MYSQL_TIME ltime;
+  (void) item->get_date(&ltime, sql_mode_for_dates(current_thd));
+}
+
+
+void Type_handler_string_result::Item_update_null_value(Item *item) const
+{
+  StringBuffer<MAX_FIELD_WIDTH> tmp;
+  (void) item->val_str(&tmp);
+}
+
+
+void Type_handler_real_result::Item_update_null_value(Item *item) const
+{
+  (void) item->val_real();
+}
+
+
+void Type_handler_decimal_result::Item_update_null_value(Item *item) const
+{
+  my_decimal tmp;
+  (void) item->val_decimal(&tmp);
+}
+
+
+void Type_handler_int_result::Item_update_null_value(Item *item) const
+{
+  (void) item->val_int();
+}
+
+
+void Type_handler_bool::Item_update_null_value(Item *item) const
+{
+  (void) item->val_bool();
+}
+
+
+/*************************************************************************/
+
 int Type_handler_time_common::Item_save_in_field(Item *item, Field *field,
                                                  bool no_conversions) const
 {
diff --git a/sql/sql_type.h b/sql/sql_type.h
index 5999577c97f..d4e588e244d 100644
--- a/sql/sql_type.h
+++ b/sql/sql_type.h
@@ -1420,6 +1420,7 @@ public:
 
   virtual uint32 max_display_length(const Item *item) const= 0;
   virtual uint32 calc_pack_length(uint32 length) const= 0;
+  virtual void Item_update_null_value(Item *item) const= 0;
   virtual bool Item_save_in_value(Item *item, st_value *value) const= 0;
   virtual void Item_param_setup_conversion(THD *thd, Item_param *) const {}
   virtual void Item_param_set_param_func(Item_param *param,
@@ -1789,6 +1790,7 @@ public:
     DBUG_ASSERT(0);
     return true;
   }
+  void Item_update_null_value(Item *item) const;
   int Item_save_in_field(Item *item, Field *field, bool no_conversions) const
   {
     DBUG_ASSERT(0);
@@ -2041,6 +2043,7 @@ public:
                                  Item_param *param,
                                  const Type_all_attributes *attr,
                                  const st_value *value) const;
+  void Item_update_null_value(Item *item) const;
   int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
   Item *make_const_item_for_comparison(THD *, Item *src, const Item *cmp) const;
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
@@ -2129,6 +2132,7 @@ public:
   {
     return Item_send_str(item, protocol, buf);
   }
+  void Item_update_null_value(Item *item) const;
   int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
   Item *make_const_item_for_comparison(THD *, Item *src, const Item *cmp) const;
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
@@ -2330,6 +2334,7 @@ public:
                                  Item_param *param,
                                  const Type_all_attributes *attr,
                                  const st_value *value) const;
+  void Item_update_null_value(Item *item) const;
   int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
   Item *make_const_item_for_comparison(THD *, Item *src, const Item *cmp) const;
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
@@ -2503,6 +2508,7 @@ public:
     return Item_temporal_precision(item, false);
   }
   uint Item_decimal_precision(const Item *item) const;
+  void Item_update_null_value(Item *item) const;
   bool Item_save_in_value(Item *item, st_value *value) const;
   void Item_param_setup_conversion(THD *thd, Item_param *) const;
   void Item_param_set_param_func(Item_param *param,
@@ -2740,6 +2746,7 @@ class Type_handler_bool: public Type_handler_long
 public:
   const Name name() const { return m_name_bool; }
   bool is_bool_type() const { return true; }
+  void Item_update_null_value(Item *item) const;
   bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *) const;
 };
 
@@ -3038,6 +3045,7 @@ public:
   {
     return Item_send_time(item, protocol, buf);
   }
+  void Item_update_null_value(Item *item) const;
   int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
   String *print_item_value(THD *thd, Item *item, String *str) const;
   Item_cache *Item_get_cache(THD *thd, const Item *item) const;
@@ -3140,6 +3148,7 @@ public:
   {
     return Item_send_date(item, protocol, buf);
   }
+  void Item_update_null_value(Item *item) const;
   int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
   Item *make_const_item_for_comparison(THD *, Item *src, const Item *cmp) const;
   bool set_comparator_func(Arg_comparator *cmp) const;