Drizzled Public API Documentation

row.cc
1 /* Copyright (C) 2000 MySQL AB
2 
3  This program is free software; you can redistribute it and/or modify
4  it under the terms of the GNU General Public License as published by
5  the Free Software Foundation; version 2 of the License.
6 
7  This program is distributed in the hope that it will be useful,
8  but WITHOUT ANY WARRANTY; without even the implied warranty of
9  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  GNU General Public License for more details.
11 
12  You should have received a copy of the GNU General Public License
13  along with this program; if not, write to the Free Software
14  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
15 
16 #include <config.h>
17 #include <drizzled/error.h>
18 #include <drizzled/session.h>
19 #include <drizzled/item/row.h>
20 
21 namespace drizzled {
22 
38  Item(), used_tables_cache(0), const_item_cache(1), with_null(0)
39 {
40 
41  //TODO: think placing 2-3 component items in item (as it done for function)
42  if ((arg_count= arg.size()))
43  items= (Item**) memory::sql_alloc(sizeof(Item*)*arg_count);
44  else
45  items= 0;
46  List<Item>::iterator li(arg.begin());
47  uint32_t i= 0;
48  while (Item* item= li++)
49  {
50  items[i]= item;
51  i++;
52  }
53 }
54 
55 void Item_row::illegal_method_call(const char *)
56 {
57  assert(false);
58  my_error(ER_OPERAND_COLUMNS, MYF(0), 1);
59 }
60 
61 bool Item_row::fix_fields(Session *session, Item **)
62 {
63  assert(fixed == 0);
64  null_value= 0;
65  maybe_null= 0;
66  Item **arg, **arg_end;
67  for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
68  {
69  if ((*arg)->fix_fields(session, arg))
70  return true;
71  // we can't assign 'item' before, because fix_fields() can change arg
72  Item *item= *arg;
73  used_tables_cache |= item->used_tables();
74  const_item_cache&= item->const_item() && !with_null;
75  if (const_item_cache)
76  {
77  if (item->cols() > 1)
78  with_null|= item->null_inside();
79  else
80  {
81  if (item->is_null())
82  with_null|= 1;
83  }
84  }
85  maybe_null|= item->maybe_null;
86  with_sum_func= with_sum_func || item->with_sum_func;
87  }
88  fixed= 1;
89  return false;
90 }
91 
92 
93 void Item_row::cleanup()
94 {
95  Item::cleanup();
96  /* Reset to the original values */
97  used_tables_cache= 0;
98  const_item_cache= true;
99  with_null= 0;
100 
101  return;
102 }
103 
104 
105 void Item_row::split_sum_func(Session *session, Item **ref_pointer_array,
106  List<Item> &fields)
107 {
108  Item **arg, **arg_end;
109  for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
110  (*arg)->split_sum_func(session, ref_pointer_array, fields, arg, true);
111 }
112 
113 
114 void Item_row::update_used_tables()
115 {
116  used_tables_cache= 0;
117  const_item_cache= true;
118  for (uint32_t i= 0; i < arg_count; i++)
119  {
120  items[i]->update_used_tables();
121  used_tables_cache|= items[i]->used_tables();
122  const_item_cache&= items[i]->const_item();
123  }
124 }
125 
126 void Item_row::fix_after_pullout(Select_Lex *new_parent, Item **)
127 {
128  used_tables_cache= 0;
129  const_item_cache= true;
130  for (uint32_t i= 0; i < arg_count; i++)
131  {
132  items[i]->fix_after_pullout(new_parent, &items[i]);
133  used_tables_cache|= items[i]->used_tables();
134  const_item_cache&= items[i]->const_item();
135  }
136 }
137 
138 bool Item_row::check_cols(uint32_t c)
139 {
140  if (c != arg_count)
141  {
142  my_error(ER_OPERAND_COLUMNS, MYF(0), c);
143  return 1;
144  }
145  return 0;
146 }
147 
149 {
150  str->append('(');
151  for (uint32_t i= 0; i < arg_count; i++)
152  {
153  if (i)
154  str->append(',');
155  items[i]->print(str);
156  }
157  str->append(')');
158 }
159 
160 
161 bool Item_row::walk(Item_processor processor, bool walk_subquery, unsigned char *arg)
162 {
163  for (uint32_t i= 0; i < arg_count; i++)
164  {
165  if (items[i]->walk(processor, walk_subquery, arg))
166  return 1;
167  }
168  return (this->*processor)(arg);
169 }
170 
171 
172 Item *Item_row::transform(Item_transformer transformer, unsigned char *arg)
173 {
174  for (uint32_t i= 0; i < arg_count; i++)
175  {
176  Item *new_item= items[i]->transform(transformer, arg);
177  if (!new_item)
178  return 0;
179  items[i]= new_item;
180  }
181  return (this->*transformer)(arg);
182 }
183 
184 void Item_row::bring_value()
185 {
186  for (uint32_t i= 0; i < arg_count; i++)
187  items[i]->bring_value();
188 }
189 
190 } /* namespace drizzled */
virtual bool const_item() const
Definition: item.h:495
Item_row(List< Item > &)
Definition: row.cc:37
bool fixed
Definition: item.h:120
bool null_value
Definition: item.h:122
Item * transform(Item_transformer transformer, unsigned char *arg)
Definition: row.cc:172
virtual Item * transform(Item_transformer transformer, unsigned char *arg)
Definition: item.cc:387
virtual void print(String *str)
Definition: row.cc:148
bool maybe_null
Definition: item.h:121
void fix_after_pullout(Select_Lex *new_parent, Item **ref)
Definition: row.cc:126
virtual void fix_after_pullout(Select_Lex *new_parent, Item **ref)
Definition: item.cc:75
virtual void print(String *str)
Definition: item.cc:362
virtual table_map used_tables() const
Definition: item.h:451