release/src/router/mysql/sql/item_row.cc

   1 /*
   2    Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; version 2 of the License.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program; if not, write to the Free Software
  15    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
  16 */
  17
  18 #include "mysql_priv.h"
  19
  20 /**
  21   Row items used for comparing rows and IN operations on rows:
  22
  23   @verbatim
  24   (a, b, c) > (10, 10, 30)
  25   (a, b, c) = (select c, d, e, from t1 where x=12)
  26   (a, b, c) IN ((1,2,2), (3,4,5), (6,7,8)
  27   (a, b, c) IN (select c, d, e, from t1)
  28   @endverbatim
  29
  30   @todo
  31     think placing 2-3 component items in item (as it done for function
  32 */
  33
  34 Item_row::Item_row(List<Item> &arg):
  35   Item(), used_tables_cache(0), not_null_tables_cache(0),
  36   const_item_cache(1), with_null(0)
  37 {
  38
  39   //TODO: think placing 2-3 component items in item (as it done for function)
  40   if ((arg_count= arg.elements))
  41     items= (Item**) sql_alloc(sizeof(Item*)*arg_count);
  42   else
  43     items= 0;
  44   List_iterator<Item> li(arg);
  45   uint i= 0;
  46   Item *item;
  47   while ((item= li++))
  48   {
  49     items[i]= item;
  50     i++;
  51   }
  52 }
  53
  54 void Item_row::illegal_method_call(const char *method)
  55 {
  56   DBUG_ENTER("Item_row::illegal_method_call");
  57   DBUG_PRINT("error", ("!!! %s method was called for row item", method));
  58   DBUG_ASSERT(0);
  59   my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
  60   DBUG_VOID_RETURN;
  61 }
  62
  63 bool Item_row::fix_fields(THD *thd, Item **ref)
  64 {
  65   DBUG_ASSERT(fixed == 0);
  66   null_value= 0;
  67   maybe_null= 0;
  68   Item **arg, **arg_end;
  69   for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
  70   {
  71     if ((*arg)->fix_fields(thd, arg))
  72       return TRUE;
  73     // we can't assign 'item' before, because fix_fields() can change arg
  74     Item *item= *arg;
  75     used_tables_cache |= item->used_tables();
  76     const_item_cache&= item->const_item() && !with_null;
  77     not_null_tables_cache|= item->not_null_tables();
  78
  79     if (const_item_cache)
  80     {
  81       if (item->cols() > 1)
  82         with_null|= item->null_inside();
  83       else
  84       {
  85         if (item->is_null())
  86           with_null|= 1;
  87       }
  88     }
  89     maybe_null|= item->maybe_null;
  90     with_sum_func= with_sum_func || item->with_sum_func;
  91   }
  92   fixed= 1;
  93   return FALSE;
  94 }
  95
  96
  97 void Item_row::cleanup()
  98 {
  99   DBUG_ENTER("Item_row::cleanup");
 100
 101   Item::cleanup();
 102   /* Reset to the original values */
 103   used_tables_cache= 0;
 104   const_item_cache= 1;
 105   with_null= 0;
 106
 107   DBUG_VOID_RETURN;
 108 }
 109
 110
 111 void Item_row::split_sum_func(THD *thd, Item **ref_pointer_array,
 112                               List<Item> &fields)
 113 {
 114   Item **arg, **arg_end;
 115   for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
 116     (*arg)->split_sum_func2(thd, ref_pointer_array, fields, arg, TRUE);
 117 }
 118
 119
 120 void Item_row::update_used_tables()
 121 {
 122   used_tables_cache= 0;
 123   const_item_cache= 1;
 124   for (uint i= 0; i < arg_count; i++)
 125   {
 126     items[i]->update_used_tables();
 127     used_tables_cache|= items[i]->used_tables();
 128     const_item_cache&= items[i]->const_item();
 129   }
 130 }
 131
 132 bool Item_row::check_cols(uint c)
 133 {
 134   if (c != arg_count)
 135   {
 136     my_error(ER_OPERAND_COLUMNS, MYF(0), c);
 137     return 1;
 138   }
 139   return 0;
 140 }
 141
 142 void Item_row::print(String *str, enum_query_type query_type)
 143 {
 144   str->append('(');
 145   for (uint i= 0; i < arg_count; i++)
 146   {
 147     if (i)
 148       str->append(',');
 149     items[i]->print(str, query_type);
 150   }
 151   str->append(')');
 152 }
 153
 154
 155 bool Item_row::walk(Item_processor processor, bool walk_subquery, uchar *arg)
 156 {
 157   for (uint i= 0; i < arg_count; i++)
 158   {
 159     if (items[i]->walk(processor, walk_subquery, arg))
 160       return 1;
 161   }
 162   return (this->*processor)(arg);
 163 }
 164
 165
 166 Item *Item_row::transform(Item_transformer transformer, uchar *arg)
 167 {
 168   DBUG_ASSERT(!current_thd->is_stmt_prepare());
 169
 170   for (uint i= 0; i < arg_count; i++)
 171   {
 172     Item *new_item= items[i]->transform(transformer, arg);
 173     if (!new_item)
 174       return 0;
 175
 176     /*
 177       THD::change_item_tree() should be called only if the tree was
 178       really transformed, i.e. when a new item has been created.
 179       Otherwise we'll be allocating a lot of unnecessary memory for
 180       change records at each execution.
 181     */
 182     if (items[i] != new_item)
 183       current_thd->change_item_tree(&items[i], new_item);
 184   }
 185   return (this->*transformer)(arg);
 186 }
 187
 188 void Item_row::bring_value()
 189 {
 190   for (uint i= 0; i < arg_count; i++)
 191     items[i]->bring_value();
 192 }