1 /* Copyright (c) 2000, 2021, Oracle and/or its affiliates. 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, version 2.0, 5 as published by the Free Software Foundation. 6 7 This program is also distributed with certain software (including 8 but not limited to OpenSSL) that is licensed under separate terms, 9 as designated in a particular file or component or in included license 10 documentation. The authors of MySQL hereby grant you an additional 11 permission to link the program and your derivative works with the 12 separately licensed software that they have included with MySQL. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License, version 2.0, for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ 22 23 /* Functions to create an item. Used by sql/sql_yacc.yy */ 24 25 #ifndef ITEM_CREATE_H 26 #define ITEM_CREATE_H 27 28 #include "my_global.h" 29 #include "mysql/mysql_lex_string.h" // LEX_STRING 30 #include "item_func.h" // Cast_target 31 32 class Item; 33 class PT_item_list; 34 class THD; 35 36 typedef struct charset_info_st CHARSET_INFO; 37 typedef struct st_udf_func udf_func; 38 struct Cast_type; 39 40 /** 41 Public function builder interface. 42 The parser (sql/sql_yacc.yy) uses a factory / builder pattern to 43 construct an <code>Item</code> object for each function call. 44 All the concrete function builders implements this interface, 45 either directly or indirectly with some adapter helpers. 46 Keeping the function creation separated from the bison grammar allows 47 to simplify the parser, and avoid the need to introduce a new token 48 for each function, which has undesirable side effects in the grammar. 49 */ 50 51 class Create_func 52 { 53 public: 54 /** 55 The builder create method. 56 Given the function name and list or arguments, this method creates 57 an <code>Item</code> that represents the function call. 58 In case or errors, a NULL item is returned, and an error is reported. 59 Note that the <code>thd</code> object may be modified by the builder. 60 In particular, the following members/methods can be set/called, 61 depending on the function called and the function possible side effects. 62 <ul> 63 <li><code>thd->lex->binlog_row_based_if_mixed</code></li> 64 <li><code>thd->lex->current_context()</code></li> 65 <li><code>thd->lex->safe_to_cache_query</code></li> 66 <li><code>thd->lex->uncacheable(UNCACHEABLE_SIDEEFFECT)</code></li> 67 <li><code>thd->lex->uncacheable(UNCACHEABLE_RAND)</code></li> 68 <li><code>thd->lex->add_time_zone_tables_to_query_tables(thd)</code></li> 69 </ul> 70 @param thd The current thread 71 @param name The function name 72 @param item_list The list of arguments to the function, can be NULL 73 @return An item representing the parsed function call, or NULL 74 */ 75 virtual Item *create_func(THD *thd, LEX_STRING name, PT_item_list *item_list) 76 = 0; 77 78 protected: 79 /** Constructor */ Create_func()80 Create_func() {} 81 /** Destructor */ ~Create_func()82 virtual ~Create_func() {} 83 }; 84 85 86 /** 87 Function builder for qualified functions. 88 This builder is used with functions call using a qualified function name 89 syntax, as in <code>db.func(expr, expr, ...)</code>. 90 */ 91 92 class Create_qfunc : public Create_func 93 { 94 public: 95 /** 96 The builder create method, for unqualified functions. 97 This builder will use the current database for the database name. 98 @param thd The current thread 99 @param name The function name 100 @param item_list The list of arguments to the function, can be NULL 101 @return An item representing the parsed function call 102 */ 103 virtual Item *create_func(THD *thd, LEX_STRING name, PT_item_list *item_list); 104 105 /** 106 The builder create method, for qualified functions. 107 @param thd The current thread 108 @param db The database name or NULL_STR to use the default db name 109 @param name The function name 110 @param use_explicit_name Should the function be represented as 'db.name'? 111 @param item_list The list of arguments to the function, can be NULL 112 @return An item representing the parsed function call 113 */ 114 virtual Item* create(THD *thd, LEX_STRING db, LEX_STRING name, 115 bool use_explicit_name, PT_item_list *item_list) = 0; 116 117 protected: 118 /** Constructor. */ Create_qfunc()119 Create_qfunc() {} 120 /** Destructor. */ ~Create_qfunc()121 virtual ~Create_qfunc() {} 122 }; 123 124 125 /** 126 Find the native function builder associated with a given function name. 127 @param thd The current thread 128 @param name The native function name 129 @return The native function builder associated with the name, or NULL 130 */ 131 extern Create_func * find_native_function_builder(THD *thd, LEX_STRING name); 132 133 134 /** 135 Find the function builder for qualified functions. 136 @param thd The current thread 137 @return A function builder for qualified functions 138 */ 139 extern Create_qfunc * find_qualified_function_builder(THD *thd); 140 141 142 #ifdef HAVE_DLOPEN 143 /** 144 Function builder for User Defined Functions. 145 */ 146 147 class Create_udf_func : public Create_func 148 { 149 public: 150 virtual Item *create_func(THD *thd, LEX_STRING name, PT_item_list *item_list); 151 152 /** 153 The builder create method, for User Defined Functions. 154 @param thd The current thread 155 @param fct The User Defined Function metadata 156 @param item_list The list of arguments to the function, can be NULL 157 @return An item representing the parsed function call 158 */ 159 Item *create(THD *thd, udf_func *fct, PT_item_list *item_list); 160 161 /** Singleton. */ 162 static Create_udf_func s_singleton; 163 164 protected: 165 /** Constructor. */ Create_udf_func()166 Create_udf_func() {} 167 /** Destructor. */ ~Create_udf_func()168 virtual ~Create_udf_func() {} 169 }; 170 #endif 171 172 173 /** 174 Builder for cast expressions. 175 @param thd The current thread 176 @param pos Location of casting expression 177 @param a The item to cast 178 @param type the type casted into 179 */ 180 Item * 181 create_func_cast(THD *thd, const POS &pos, Item *a, const Cast_type *type); 182 Item * 183 create_func_cast(THD *thd, const POS &pos, Item *a, Cast_target cast_target, 184 const CHARSET_INFO *cs_arg); 185 186 Item *create_temporal_literal(THD *thd, 187 const char *str, size_t length, 188 const CHARSET_INFO *cs, 189 enum_field_types type, bool send_error); 190 191 int item_create_init(); 192 void item_create_cleanup(); 193 194 #endif 195 196