MDEV-12687 Split Item::send() into virtual method in Type_handler

sql/item.cc

@@ -6861,127 +6861,11 @@ bool Item_time_literal::get_date(MYSQL_TIME *ltime, ulonglong fuzzy_date)
   Pack data in buffer for sending.
 */
 
-bool Item_null::send(Protocol *protocol, String *packet)
+bool Item_null::send(Protocol *protocol, st_value *buffer)
 {
   return protocol->store_null();
 }
 
-/**
-  This is only called from items that is not of type item_field.
-*/
-
-bool Item::send(Protocol *protocol, String *buffer)
-{
-  bool UNINIT_VAR(result);                       // Will be set if null_value == 0
-  enum_field_types f_type;
-
-  switch ((f_type=field_type())) {
-  default:
-  case MYSQL_TYPE_NULL:
-  case MYSQL_TYPE_DECIMAL:
-  case MYSQL_TYPE_ENUM:
-  case MYSQL_TYPE_SET:
-  case MYSQL_TYPE_TINY_BLOB:
-  case MYSQL_TYPE_MEDIUM_BLOB:
-  case MYSQL_TYPE_LONG_BLOB:
-  case MYSQL_TYPE_BLOB:
-  case MYSQL_TYPE_GEOMETRY:
-  case MYSQL_TYPE_STRING:
-  case MYSQL_TYPE_VAR_STRING:
-  case MYSQL_TYPE_VARCHAR:
-  case MYSQL_TYPE_BIT:
-  case MYSQL_TYPE_NEWDECIMAL:
-  {
-    String *res;
-    if ((res=val_str(buffer)))
-    {
-      DBUG_ASSERT(!null_value);
-      result= protocol->store(res->ptr(),res->length(),res->charset());
-    }
-    else
-    {
-      DBUG_ASSERT(null_value);
-    }
-    break;
-  }
-  case MYSQL_TYPE_TINY:
-  {
-    longlong nr;
-    nr= val_int();
-    if (!null_value)
-      result= protocol->store_tiny(nr);
-    break;
-  }
-  case MYSQL_TYPE_SHORT:
-  case MYSQL_TYPE_YEAR:
-  {
-    longlong nr;
-    nr= val_int();
-    if (!null_value)
-      result= protocol->store_short(nr);
-    break;
-  }
-  case MYSQL_TYPE_INT24:
-  case MYSQL_TYPE_LONG:
-  {
-    longlong nr;
-    nr= val_int();
-    if (!null_value)
-      result= protocol->store_long(nr);
-    break;
-  }
-  case MYSQL_TYPE_LONGLONG:
-  {
-    longlong nr;
-    nr= val_int();
-    if (!null_value)
-      result= protocol->store_longlong(nr, unsigned_flag);
-    break;
-  }
-  case MYSQL_TYPE_FLOAT:
-  {
-    float nr;
-    nr= (float) val_real();
-    if (!null_value)
-      result= protocol->store(nr, decimals, buffer);
-    break;
-  }
-  case MYSQL_TYPE_DOUBLE:
-  {
-    double nr= val_real();
-    if (!null_value)
-      result= protocol->store(nr, decimals, buffer);
-    break;
-  }
-  case MYSQL_TYPE_DATETIME:
-  case MYSQL_TYPE_DATE:
-  case MYSQL_TYPE_TIMESTAMP:
-  {
-    MYSQL_TIME tm;
-    get_date(&tm, sql_mode_for_dates(current_thd));
-    if (!null_value)
-    {
-      if (f_type == MYSQL_TYPE_DATE)
-	return protocol->store_date(&tm);
-      else
-	result= protocol->store(&tm, decimals);
-    }
-    break;
-  }
-  case MYSQL_TYPE_TIME:
-  {
-    MYSQL_TIME tm;
-    get_time(&tm);
-    if (!null_value)
-      result= protocol->store_time(&tm, decimals);
-    break;
-  }
-  }
-  if (null_value)
-    result= protocol->store_null();
-  return result;
-}
-
 
 /**
   Check if an item is a constant one and can be cached.
@@ -7053,7 +6937,7 @@ bool Item::find_item_processor(void *arg)
   return (this == ((Item *) arg));
 }
 
-bool Item_field::send(Protocol *protocol, String *buffer)
+bool Item_field::send(Protocol *protocol, st_value *buffer)
 {
   return protocol->store(result_field);
 }
@@ -7783,11 +7667,11 @@ void Item_ref::print(String *str, enum_query_type query_type)
 }
 
 
-bool Item_ref::send(Protocol *prot, String *tmp)
+bool Item_ref::send(Protocol *prot, st_value *buffer)
 {
   if (result_field)
     return prot->store(result_field);
-  return (*ref)->send(prot, tmp);
+  return (*ref)->send(prot, buffer);
 }
 
 
@@ -8142,7 +8026,7 @@ bool Item_cache_wrapper::fix_fields(THD *thd  __attribute__((unused)),
   return FALSE;
 }
 
-bool Item_cache_wrapper::send(Protocol *protocol, String *buffer)
+bool Item_cache_wrapper::send(Protocol *protocol, st_value *buffer)
 {
   if (result_field)
     return protocol->store(result_field);
@@ -8473,7 +8357,7 @@ Item* Item_cache_wrapper::get_tmp_table_item(THD *thd)
 }
 
 
-bool Item_direct_view_ref::send(Protocol *protocol, String *buffer)
+bool Item_direct_view_ref::send(Protocol *protocol, st_value *buffer)
 {
   if (check_null_ref())
     return protocol->store_null();
@@ -8850,7 +8734,7 @@ bool Item_default_value::get_date(MYSQL_TIME *ltime,ulonglong fuzzydate)
   return Item_field::get_date(ltime, fuzzydate);
 }
 
-bool Item_default_value::send(Protocol *protocol, String *buffer)
+bool Item_default_value::send(Protocol *protocol, st_value *buffer)
 {
   calculate();
   return Item_field::send(protocol, buffer);
@@ -8957,7 +8841,7 @@ bool Item_ignore_value::get_date(MYSQL_TIME *ltime, ulonglong fuzzydate)
   return TRUE;
 }
 
-bool Item_ignore_value::send(Protocol *protocol, String *buffer)
+bool Item_ignore_value::send(Protocol *protocol, st_value *buffer)
 {
   DBUG_ASSERT(0); // never should be called
   return TRUE;

sql/item.h

@@ -55,6 +55,23 @@ struct st_value
 
 C_MODE_END
 
+
+template<size_t buffer_size>
+class ValueBuffer: public st_value
+{
+  char buffer[buffer_size];
+  void reset_buffer()
+  {
+    m_string.set(buffer, buffer_size, &my_charset_bin);
+  }
+public:
+  ValueBuffer()
+  {
+    reset_buffer();
+  }
+};
+
+
 const char *dbug_print_item(Item *item);
 
 class Protocol;
@@ -693,7 +710,10 @@ class Item: public Value_source,
   { return NULL; }
   virtual int save_safe_in_field(Field *field)
   { return save_in_field(field, 1); }
-  virtual bool send(Protocol *protocol, String *str);
+  virtual bool send(Protocol *protocol, st_value *buffer)
+  {
+    return type_handler()->Item_send(this, protocol, buffer);
+  }
   virtual bool eq(const Item *, bool binary_cmp) const;
   virtual enum_field_types field_type() const= 0;
   virtual const Type_handler *type_handler() const
@@ -2089,7 +2109,7 @@ class Item_sp_variable :public Item
   inline bool const_item() const;
   
   inline int save_in_field(Field *field, bool no_conversions);
-  inline bool send(Protocol *protocol, String *str);
+  inline bool send(Protocol *protocol, st_value *buffer);
   bool check_vcol_func_processor(void *arg) 
   {
     return mark_unsupported_function(m_name.str, arg, VCOL_IMPOSSIBLE);
@@ -2110,9 +2130,9 @@ inline int Item_sp_variable::save_in_field(Field *field, bool no_conversions)
   return this_item()->save_in_field(field, no_conversions);
 }
 
-inline bool Item_sp_variable::send(Protocol *protocol, String *str)
+inline bool Item_sp_variable::send(Protocol *protocol, st_value *buffer)
 {
-  return this_item()->send(protocol, str);
+  return this_item()->send(protocol, buffer);
 }
 
 
@@ -2398,9 +2418,9 @@ class Item_name_const : public Item
     return  value_item->save_in_field(field, no_conversions);
   }
 
-  bool send(Protocol *protocol, String *str)
+  bool send(Protocol *protocol, st_value *buffer)
   {
-    return value_item->send(protocol, str);
+    return value_item->send(protocol, buffer);
   }
   bool check_vcol_func_processor(void *arg) 
   {
@@ -2532,7 +2552,6 @@ class Item_ident_for_show :public Item
   {
     Type_std_attributes::set(par_field);
   }
-
   enum Type type() const { return FIELD_ITEM; }
   double val_real() { return field->val_real(); }
   longlong val_int() { return field->val_int(); }
@@ -2591,7 +2610,7 @@ class Item_field :public Item_ident
   my_decimal *val_decimal_result(my_decimal *);
   bool val_bool_result();
   bool is_null_result();
-  bool send(Protocol *protocol, String *str_arg);
+  bool send(Protocol *protocol, st_value *buffer);
   void reset_field(Field *f);
   bool fix_fields(THD *, Item **);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref);
@@ -2829,7 +2848,7 @@ class Item_null :public Item_basic_constant
   my_decimal *val_decimal(my_decimal *);
   int save_in_field(Field *field, bool no_conversions);
   int save_safe_in_field(Field *field);
-  bool send(Protocol *protocol, String *str);
+  bool send(Protocol *protocol, st_value *buffer);
   enum Item_result result_type () const { return STRING_RESULT; }
   enum_field_types field_type() const   { return MYSQL_TYPE_NULL; }
   bool basic_const_item() const { return 1; }
@@ -4229,7 +4248,7 @@ class Item_ref :public Item_ident
   my_decimal *val_decimal_result(my_decimal *);
   bool val_bool_result();
   bool is_null_result();
-  bool send(Protocol *prot, String *tmp);
+  bool send(Protocol *prot, st_value *buffer);
   void make_field(THD *thd, Send_field *field);
   bool fix_fields(THD *, Item **);
   void fix_after_pullout(st_select_lex *new_parent, Item **ref);
@@ -4498,7 +4517,7 @@ class Item_cache_wrapper :public Item_result_field
   bool val_bool();
   bool is_null();
   bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
-  bool send(Protocol *protocol, String *buffer);
+  bool send(Protocol *protocol, st_value *buffer);
   void save_org_in_field(Field *field,
                          fast_field_copier data __attribute__ ((__unused__)))
   {
@@ -4712,7 +4731,7 @@ class Item_direct_view_ref :public Item_direct_ref
     }
     return Item_direct_ref::get_date(ltime, fuzzydate);
   }
-  bool send(Protocol *protocol, String *buffer);
+  bool send(Protocol *protocol, st_value *buffer);
   void save_org_in_field(Field *field,
                          fast_field_copier data __attribute__ ((__unused__)))
   {
@@ -5226,7 +5245,7 @@ class Item_default_value : public Item_field
   longlong val_int();
   my_decimal *val_decimal(my_decimal *decimal_value);
   bool get_date(MYSQL_TIME *ltime,ulonglong fuzzydate);
-  bool send(Protocol *protocol, String *buffer);
+  bool send(Protocol *protocol, st_value *buffer);
   int save_in_field(Field *field_arg, bool no_conversions);
   bool save_in_param(THD *thd, Item_param *param)
   {
@@ -5278,7 +5297,7 @@ class Item_ignore_value : public Item_default_value
   longlong val_int();
   my_decimal *val_decimal(my_decimal *decimal_value);
   bool get_date(MYSQL_TIME *ltime,ulonglong fuzzydate);
-  bool send(Protocol *protocol, String *buffer);
+  bool send(Protocol *protocol, st_value *buffer);
 };
 
 

sql/item_func.cc

@@ -4980,7 +4980,7 @@ void Item_func_set_user_var::print_as_stmt(String *str,
   args[0]->print_parenthesised(str, query_type, precedence());
 }
 
-bool Item_func_set_user_var::send(Protocol *protocol, String *str_arg)
+bool Item_func_set_user_var::send(Protocol *protocol, st_value *buffer)
 {
   if (result_field)
   {
@@ -4988,7 +4988,7 @@ bool Item_func_set_user_var::send(Protocol *protocol, String *str_arg)
     update();
     return protocol->store(result_field);
   }
-  return Item::send(protocol, str_arg);
+  return Item::send(protocol, buffer);
 }
 
 void Item_func_set_user_var::make_field(THD *thd, Send_field *tmp_field)

sql/item_func.h

@@ -2248,7 +2248,7 @@ class Item_func_set_user_var :public Item_func_user_var
   bool is_null_result();
   bool update_hash(void *ptr, uint length, enum Item_result type,
                    CHARSET_INFO *cs, bool unsigned_arg);
-  bool send(Protocol *protocol, String *str_arg);
+  bool send(Protocol *protocol, st_value *buffer);
   void make_field(THD *thd, Send_field *tmp_field);
   bool check(bool use_result_field);
   void save_item_result(Item *item);

sql/protocol.cc

@@ -791,8 +791,7 @@ bool Protocol::send_result_set_metadata(List<Item> *list, uint flags)
 {
   List_iterator_fast<Item> it(*list);
   Item *item;
-  uchar buff[MAX_FIELD_WIDTH];
-  String tmp((char*) buff,sizeof(buff),&my_charset_bin);
+  ValueBuffer<MAX_FIELD_WIDTH> tmp;
   Protocol_text prot(thd);
   String *local_packet= prot.storage_packet();
   CHARSET_INFO *thd_charset= thd->variables.character_set_results;
@@ -800,7 +799,9 @@ bool Protocol::send_result_set_metadata(List<Item> *list, uint flags)
 
   if (flags & SEND_NUM_ROWS)
   {				// Packet with number of elements
+    uchar buff[MAX_INT_WIDTH];
     uchar *pos= net_store_length(buff, list->elements);
+    DBUG_ASSERT(pos <= buff + sizeof(buff));
     if (my_net_write(&thd->net, buff, (size_t) (pos-buff)))
       DBUG_RETURN(1);
   }
@@ -968,15 +969,20 @@ bool Protocol::write()
 
 bool Protocol::send_result_set_row(List<Item> *row_items)
 {
-  char buffer[MAX_FIELD_WIDTH];
-  String str_buffer(buffer, sizeof (buffer), &my_charset_bin);
   List_iterator_fast<Item> it(*row_items);
 
   DBUG_ENTER("Protocol::send_result_set_row");
 
   for (Item *item= it++; item; item= it++)
   {
-    if (item->send(this, &str_buffer))
+    /*
+      ValueBuffer::m_string can be altered during Item::send().
+      It's important to declare value_buffer inside the loop,
+      to have ValueBuffer::m_string point to ValueBuffer::buffer
+      on every iteration.
+    */
+    ValueBuffer<MAX_FIELD_WIDTH> value_buffer;
+    if (item->send(this, &value_buffer))
     {
       // If we're out of memory, reclaim some, to help us recover.
       this->free();
@@ -985,12 +991,6 @@ bool Protocol::send_result_set_row(List<Item> *row_items)
     /* Item::send() may generate an error. If so, abort the loop. */
     if (thd->is_error())
       DBUG_RETURN(TRUE);
-
-    /*
-      Reset str_buffer to its original state, as it may have been altered in
-      Item::send().
-    */
-    str_buffer.set(buffer, sizeof(buffer), &my_charset_bin);
   }
 
   DBUG_RETURN(FALSE);

sql/sql_type.cc

@@ -4061,3 +4061,114 @@ bool Type_handler_time_common::
 }
 
 /***************************************************************************/
+
+bool Type_handler_null::
+      Item_send(Item *item, Protocol *protocol, st_value *buf) const
+{
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_str(Item *item, Protocol *protocol, st_value *buf) const
+{
+  String *res;
+  if ((res= item->val_str(&buf->m_string)))
+  {
+    DBUG_ASSERT(!item->null_value);
+    return protocol->store(res->ptr(), res->length(), res->charset());
+  }
+  DBUG_ASSERT(item->null_value);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_tiny(Item *item, Protocol *protocol, st_value *buf) const
+{
+  longlong nr= item->val_int();
+  if (!item->null_value)
+    return protocol->store_tiny(nr);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_short(Item *item, Protocol *protocol, st_value *buf) const
+{
+  longlong nr= item->val_int();
+  if (!item->null_value)
+    return protocol->store_short(nr);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_long(Item *item, Protocol *protocol, st_value *buf) const
+{
+  longlong nr= item->val_int();
+  if (!item->null_value)
+    return protocol->store_long(nr);
+  return protocol->store_null();
+}
+
+bool Type_handler::
+       Item_send_longlong(Item *item, Protocol *protocol, st_value *buf) const
+{
+  longlong nr= item->val_int();
+  if (!item->null_value)
+    return protocol->store_longlong(nr, item->unsigned_flag);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_float(Item *item, Protocol *protocol, st_value *buf) const
+{
+  float nr= (float) item->val_real();
+  if (!item->null_value)
+    return protocol->store(nr, item->decimals, &buf->m_string);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_double(Item *item, Protocol *protocol, st_value *buf) const
+{
+  double nr= item->val_real();
+  if (!item->null_value)
+    return protocol->store(nr, item->decimals, &buf->m_string);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_datetime(Item *item, Protocol *protocol, st_value *buf) const
+{
+  item->get_date(&buf->value.m_time, sql_mode_for_dates(current_thd));
+  if (!item->null_value)
+    return protocol->store(&buf->value.m_time, item->decimals);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_date(Item *item, Protocol *protocol, st_value *buf) const
+{
+  item->get_date(&buf->value.m_time, sql_mode_for_dates(current_thd));
+  if (!item->null_value)
+    return protocol->store_date(&buf->value.m_time);
+  return protocol->store_null();
+}
+
+
+bool Type_handler::
+       Item_send_time(Item *item, Protocol *protocol, st_value *buf) const
+{
+  item->get_time(&buf->value.m_time);
+  if (!item->null_value)
+    return protocol->store_time(&buf->value.m_time, item->decimals);
+  return protocol->store_null();
+}
+
+/***************************************************************************/