MDEV-14494 Move set_param_xxx() in sql_prepare.cc to methods in Item_param and Type_handler

- sql_prepare.cc: Moving functions set_param_xxx() as
  methods to Item_param

- Replacing a pointer to a function Item_param::set_param_func
  to Type_handler based implementation:
  Item_param::value now derives from Type_handler_hybrid_field_type.
  Adding new virtual methods Type_handler::Item_param_setup_conversion()
  and Type_handler::Item_param_set_param_func()

- Moving declaration of some Item_param members  from "public:" to "private:"
  (CONVERSION_INFO, value, decimal_value)

- Adding a new method Item_param::set_limit_clause_param(),
  to share duplicate code, as well as to encapsulate
  Item_param::value.

- Adding Item_param::setup_conversion_string() and
  Item_param::setup_conversion_blob() to share
  the code for binding from a client value
  (mysql_stmt_bind_param), and for binding from
  an expression (Item).

- Removing two different functions set_param_str_or_null()
  and set_param_str(). Adding a common method Item_param::set_param_str().
  Item_param::m_empty_string_is_null, used by Item_param::set_param_str().

- Removing the call for setup_one_conversion_function() from
  insert_params_from_actual_params_with_log(). It's not needed,
  because the call for ps_param->save_in_param() makes sure
  to initialized all data type dependent members properly,
  by calling setup_conversion_string() from
  Type_handler_string_result::Item_param_set_from_value()
  and by calling setup_conversion_blob() from
  Type_handler_blob_common::Item_param_set_from_value()

- Cleanup: removing multiplication to MY_CHARSET_BIN_MB_MAXLEN
  in a few places. It's 1 anyway, and will never change.

1 files changed, 33 insertions, 0 deletions

diff --git a/sql/sql_type.h b/sql/sql_type.h
index 7536cb99ec2..9b8b6863141 100644
--- a/sql/sql_type.h
+++ b/sql/sql_type.h
@@ -805,6 +805,9 @@ public:
   virtual uint32 max_display_length(const Item *item) const= 0;
   virtual uint32 calc_pack_length(uint32 length) 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,
+                                         uchar **pos, ulong len) const;
   virtual bool Item_param_set_from_value(THD *thd,
                                          Item_param *param,
                                          const Type_all_attributes *attr,
@@ -1423,6 +1426,8 @@ public:
                              const Type_cast_attributes &attr) const;
   uint Item_decimal_precision(const Item *item) const;
   bool Item_save_in_value(Item *item, st_value *value) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
   bool Item_param_set_from_value(THD *thd,
                                  Item_param *param,
                                  const Type_all_attributes *attr,
@@ -1659,6 +1664,9 @@ public:
   }
   uint Item_decimal_precision(const 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,
+                                 uchar **pos, ulong len) const;
   bool Item_param_set_from_value(THD *thd,
                                  Item_param *param,
                                  const Type_all_attributes *attr,
@@ -1785,6 +1793,8 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -1812,6 +1822,8 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -1842,6 +1854,8 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -1873,6 +1887,8 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -1996,6 +2012,8 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -2026,6 +2044,8 @@ public:
                           const Record_addr &addr,
                           const Type_all_attributes &attr,
                           TABLE *table) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -2070,6 +2090,8 @@ public:
   bool set_comparator_func(Arg_comparator *cmp) const;
   cmp_item *make_cmp_item(THD *thd, CHARSET_INFO *cs) const;
   in_vector *make_in_vector(THD *, const Item_func_in *, uint nargs) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -2153,6 +2175,8 @@ public:
                                        Type_handler_hybrid_field_type *,
                                        Type_all_attributes *atrr,
                                        Item **items, uint nitems) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 class Type_handler_date: public Type_handler_date_common
@@ -2227,6 +2251,8 @@ public:
                                        Type_handler_hybrid_field_type *,
                                        Type_all_attributes *atrr,
                                        Item **items, uint nitems) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -2307,6 +2333,8 @@ public:
                                        Type_handler_hybrid_field_type *,
                                        Type_all_attributes *atrr,
                                        Item **items, uint nitems) const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };
 
 
@@ -2567,6 +2595,7 @@ public:
                                        Type_handler_hybrid_field_type *,
                                        Type_all_attributes *atrr,
                                        Item **items, uint nitems) const;
+  void Item_param_setup_conversion(THD *thd, Item_param *) const;
 };
 
 
@@ -2660,6 +2689,8 @@ public:
   {
     return false; // Materialization does not work with GEOMETRY columns
   }
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
   bool Item_param_set_from_value(THD *thd,
                                  Item_param *param,
                                  const Type_all_attributes *attr,
@@ -2739,6 +2770,8 @@ public:
                                          const handler *file,
                                          const Schema_specification_st *schema)
                                          const;
+  void Item_param_set_param_func(Item_param *param,
+                                 uchar **pos, ulong len) const;
 };