Drizzled Public API Documentation

func.h

00001 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
00002  *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
00003  *
00004  *  Copyright (C) 2008 Sun Microsystems, Inc.
00005  *
00006  *  This program is free software; you can redistribute it and/or modify
00007  *  it under the terms of the GNU General Public License as published by
00008  *  the Free Software Foundation; version 2 of the License.
00009  *
00010  *  This program is distributed in the hope that it will be useful,
00011  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  *  GNU General Public License for more details.
00014  *
00015  *  You should have received a copy of the GNU General Public License
00016  *  along with this program; if not, write to the Free Software
00017  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00018  */
00019 
00020 
00021 
00022 #pragma once
00023 
00025 
00026 #include <drizzled/charset_info.h>
00027 #include <drizzled/item.h>
00028 #include <drizzled/item/bin_string.h>
00029 #include <drizzled/lex_string.h>
00030 #include <drizzled/sql_list.h>
00031 #include <drizzled/type/decimal.h>
00032 
00033 #include <drizzled/visibility.h>
00034 
00035 namespace drizzled
00036 {
00037 
00038 class DRIZZLED_API Item_func :
00039   public Item_result_field
00040 {
00041   Session &_session;
00042 
00043 protected:
00044   Item **args, *tmp_arg[2];
00045   /*
00046     Allowed numbers of columns in result (usually 1, which means scalar value)
00047     0 means get this number from first argument
00048   */
00049   uint32_t allowed_arg_cols;
00050 
00051 public:
00052 
00053   using Item::split_sum_func;
00054 
00055   uint32_t arg_count;
00056   table_map used_tables_cache, not_null_tables_cache;
00057   bool const_item_cache;
00058   enum Functype { UNKNOWN_FUNC,EQ_FUNC,EQUAL_FUNC,NE_FUNC,LT_FUNC,LE_FUNC,
00059                   GE_FUNC,GT_FUNC,
00060                   LIKE_FUNC,ISNULL_FUNC,ISNOTNULL_FUNC,
00061                   COND_AND_FUNC, COND_OR_FUNC, COND_XOR_FUNC,
00062                   BETWEEN, IN_FUNC, MULT_EQUAL_FUNC,
00063                   INTERVAL_FUNC, ISNOTNULLTEST_FUNC,
00064                   NOT_FUNC, NOT_ALL_FUNC,
00065                   NOW_FUNC, TRIG_COND_FUNC,
00066                   SUSERVAR_FUNC, GUSERVAR_FUNC, COLLATE_FUNC,
00067                   EXTRACT_FUNC, CHAR_TYPECAST_FUNC, FUNC_SP,
00068                   NEG_FUNC };
00069   enum optimize_type { OPTIMIZE_NONE,OPTIMIZE_KEY,OPTIMIZE_OP, OPTIMIZE_NULL,
00070                        OPTIMIZE_EQUAL };
00071   enum Type type() const { return FUNC_ITEM; }
00072   virtual enum Functype functype() const   { return UNKNOWN_FUNC; }
00073   virtual ~Item_func() {}
00074 
00075   Item_func(void);
00076 
00077   Item_func(Item *a);
00078   
00079   Item_func(Item *a,Item *b);
00080   
00081   Item_func(Item *a,Item *b,Item *c);
00082   
00083   Item_func(Item *a,Item *b,Item *c,Item *d);
00084   
00085   Item_func(Item *a,Item *b,Item *c,Item *d,Item* e);
00086   
00087   Item_func(List<Item> &list);
00088   
00089   // Constructor used for Item_cond_and/or (see Item comment)
00090   Item_func(Session *session, Item_func *item);
00091   
00092   bool fix_fields(Session *, Item **ref);
00093   void fix_after_pullout(Select_Lex *new_parent, Item **ref);
00094   table_map used_tables() const;
00095   table_map not_null_tables() const;
00096   void update_used_tables();
00097   bool eq(const Item *item, bool binary_cmp) const;
00098   virtual optimize_type select_optimize() const { return OPTIMIZE_NONE; }
00099   virtual bool have_rev_func() const { return 0; }
00100   virtual Item *key_item() const { return args[0]; }
00101   /*
00102     This method is used for debug purposes to print the name of an
00103     item to the debug log. The second use of this method is as
00104     a helper function of print(), where it is applicable.
00105     To suit both goals it should return a meaningful,
00106     distinguishable and sintactically correct string.  This method
00107     should not be used for runtime type identification, use enum
00108     {Sum}Functype and Item_func::functype()/Item_sum::sum_func()
00109     instead.
00110   */
00111   virtual const char *func_name() const { return NULL; }
00112   virtual bool const_item() const { return const_item_cache; }
00113   Item **arguments() const { return args; }
00114   void set_arguments(List<Item> &list);
00115   uint32_t argument_count() const { return arg_count; }
00116   void remove_arguments() { arg_count=0; }
00117 
00122   virtual bool check_argument_count(int) { return true ; }
00123   virtual void split_sum_func(Session *session, Item **ref_pointer_array,
00124                               List<Item> &fields);
00125 
00126   virtual void print(String *str);
00127   void print_op(String *str);
00128   void print_args(String *str, uint32_t from);
00129   virtual void fix_num_length_and_dec();
00130   void count_only_length();
00131   void count_real_length();
00132   void count_decimal_length();
00133 
00134   bool get_arg0_date(type::Time &ltime, uint32_t fuzzy_date);
00135   bool get_arg0_time(type::Time &ltime);
00136 
00137   bool is_null();
00138 
00139   virtual bool deterministic() const
00140   {
00141     return false;
00142   }
00143 
00144   void signal_divide_by_null();
00145 
00146   virtual Field *tmp_table_field() { return result_field; }
00147   virtual Field *tmp_table_field(Table *t_arg);
00148 
00149   Item *get_tmp_table_item(Session *session);
00150 
00151   type::Decimal *val_decimal(type::Decimal *);
00152 
00153   bool agg_arg_collations(DTCollation &c, Item **items, uint32_t nitems,
00154                           uint32_t flags);
00155   bool agg_arg_collations_for_comparison(DTCollation &c,
00156                                          Item **items, uint32_t nitems,
00157                                          uint32_t flags);
00158   bool agg_arg_charsets(DTCollation &c, Item **items, uint32_t nitems,
00159                         uint32_t flags, int item_sep);
00160   bool walk(Item_processor processor, bool walk_subquery, unsigned char *arg);
00161   Item *transform(Item_transformer transformer, unsigned char *arg);
00162   Item* compile(Item_analyzer analyzer, unsigned char **arg_p,
00163                 Item_transformer transformer, unsigned char *arg_t);
00164   void traverse_cond(Cond_traverser traverser,
00165                      void * arg, traverse_order order);
00166   double fix_result(double value);
00167 
00168   Session &getSession()
00169   {
00170     return _session;
00171   }
00172 
00173   Session *getSessionPtr()
00174   {
00175     return &_session;
00176   }
00177 
00178 };
00179 
00180 } /* namespace drizzled */
00181 
00182