MDEV-9395 Add Type_handler::Item_decimal_scale() and Item_divisor_precision_increment()

sql/field.h

@@ -525,27 +525,6 @@ inline bool is_temporal_type(enum_field_types type)
 }
 
 
-/**
-  Tests if field type is temporal and has time part,
-  i.e. represents TIME, DATETIME or TIMESTAMP types in SQL.
-
-  @param type    Field type, as returned by field->type().
-  @retval true   If field type is temporal type with time part.
-  @retval false  If field type is not temporal type with time part.
-*/
-inline bool is_temporal_type_with_time(enum_field_types type)
-{
-  switch (type)
-  {
-  case MYSQL_TYPE_TIME:
-  case MYSQL_TYPE_DATETIME:
-  case MYSQL_TYPE_TIMESTAMP:
-    return true;
-  default:
-    return false;
-  }
-}
-
 enum enum_vcol_info_type
 {
   VCOL_GENERATED_VIRTUAL, VCOL_GENERATED_STORED,

sql/item.h

@@ -1162,10 +1162,7 @@ class Item: public Value_source,
   */
   uint decimal_scale() const
   {
-    return decimals < NOT_FIXED_DEC ? decimals :
-           is_temporal_type_with_time(field_type()) ?
-           TIME_SECOND_PART_DIGITS :
-           MY_MIN(max_length, DECIMAL_MAX_SCALE);
+    return type_handler()->Item_decimal_scale(this);
   }
   /*
     Returns how many digits a divisor adds into a division result.
@@ -1186,10 +1183,7 @@ class Item: public Value_source,
   */
   uint divisor_precision_increment() const
   {
-    return decimals <  NOT_FIXED_DEC ? decimals :
-           is_temporal_type_with_time(field_type()) ?
-           TIME_SECOND_PART_DIGITS :
-           decimals;
+    return type_handler()->Item_divisor_precision_increment(this);
   }
   /**
     TIME or DATETIME precision of the item: 0..6

sql/sql_type.cc

@@ -3696,6 +3696,36 @@ uint Type_handler_string_result::Item_temporal_precision(Item *item,
 
 /***************************************************************************/
 
+uint Type_handler::Item_decimal_scale(const Item *item) const
+{
+  return item->decimals < NOT_FIXED_DEC ?
+         item->decimals :
+         MY_MIN(item->max_length, DECIMAL_MAX_SCALE);
+}
+
+uint Type_handler_temporal_result::
+       Item_decimal_scale_with_seconds(const Item *item) const
+{
+  return item->decimals < NOT_FIXED_DEC ?
+         item->decimals :
+         TIME_SECOND_PART_DIGITS;
+}
+
+uint Type_handler::Item_divisor_precision_increment(const Item *item) const
+{
+  return item->decimals;
+}
+
+uint Type_handler_temporal_result::
+       Item_divisor_precision_increment_with_seconds(const Item *item) const
+{
+  return item->decimals <  NOT_FIXED_DEC ?
+         item->decimals :
+         TIME_SECOND_PART_DIGITS;
+}
+
+/***************************************************************************/
+
 bool Type_handler_real_result::
        subquery_type_allows_materialization(const Item *inner,
                                             const Item *outer) const

sql/sql_type.h

@@ -479,6 +479,12 @@ class Type_handler
   }
   virtual uint Item_time_precision(Item *item) const;
   virtual uint Item_datetime_precision(Item *item) const;
+  virtual uint Item_decimal_scale(const Item *item) const;
+  /*
+    Returns how many digits a divisor adds into a division result.
+    See Item::divisor_precision_increment() in item.h for more comments.
+  */
+  virtual uint Item_divisor_precision_increment(const Item *) const;
   /**
     Makes a temporary table Field to handle numeric aggregate functions,
     e.g. SUM(DISTINCT expr), AVG(DISTINCT expr), etc.
@@ -1110,6 +1116,9 @@ class Type_handler_int_result: public Type_handler_numeric
 
 class Type_handler_temporal_result: public Type_handler
 {
+protected:
+  uint Item_decimal_scale_with_seconds(const Item *item) const;
+  uint Item_divisor_precision_increment_with_seconds(const Item *) const;
 public:
   Item_result result_type() const { return STRING_RESULT; }
   Item_result cmp_type() const { return TIME_RESULT; }
@@ -1441,6 +1450,14 @@ class Type_handler_time_common: public Type_handler_temporal_result
   {
     return MYSQL_TIMESTAMP_TIME;
   }
+  uint Item_decimal_scale(const Item *item) const
+  {
+    return Item_decimal_scale_with_seconds(item);
+  }
+  uint Item_divisor_precision_increment(const Item *item) const
+  {
+    return Item_divisor_precision_increment_with_seconds(item);
+  }
   const Type_handler *type_handler_for_comparison() 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;
@@ -1543,6 +1560,14 @@ class Type_handler_datetime_common: public Type_handler_temporal_with_date
   {
     return MYSQL_TIMESTAMP_DATETIME;
   }
+  uint Item_decimal_scale(const Item *item) const
+  {
+    return Item_decimal_scale_with_seconds(item);
+  }
+  uint Item_divisor_precision_increment(const Item *item) const
+  {
+    return Item_divisor_precision_increment_with_seconds(item);
+  }
   String *print_item_value(THD *thd, Item *item, String *str) const;
   bool Item_hybrid_func_fix_attributes(THD *thd, Item_hybrid_func *func,
                                        Item **items, uint nitems) const;
@@ -1587,6 +1612,14 @@ class Type_handler_timestamp_common: public Type_handler_temporal_with_date
   {
     return MYSQL_TIMESTAMP_DATETIME;
   }
+  uint Item_decimal_scale(const Item *item) const
+  {
+    return Item_decimal_scale_with_seconds(item);
+  }
+  uint Item_divisor_precision_increment(const Item *item) const
+  {
+    return Item_divisor_precision_increment_with_seconds(item);
+  }
   String *print_item_value(THD *thd, Item *item, String *str) const;
   bool Item_hybrid_func_fix_attributes(THD *thd, Item_hybrid_func *func,
                                        Item **items, uint nitems) const;