1/* Copyright (c) 2000, 2010, Oracle and/or its affiliates.
2 Copyright (c) 2008-2011 Monty Program Ab
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/* Functions to create an item. Used by sql/sql_yacc.yy */
18
19#ifndef ITEM_CREATE_H
20#define ITEM_CREATE_H
21
22#include "item_func.h" // Cast_target
23
24typedef struct st_udf_func udf_func;
25
26/**
27 Public function builder interface.
28 The parser (sql/sql_yacc.yy) uses a factory / builder pattern to
29 construct an <code>Item</code> object for each function call.
30 All the concrete function builders implements this interface,
31 either directly or indirectly with some adapter helpers.
32 Keeping the function creation separated from the bison grammar allows
33 to simplify the parser, and avoid the need to introduce a new token
34 for each function, which has undesirable side effects in the grammar.
35*/
36
37class Create_func
38{
39public:
40 /**
41 The builder create method.
42 Given the function name and list or arguments, this method creates
43 an <code>Item</code> that represents the function call.
44 In case or errors, a NULL item is returned, and an error is reported.
45 Note that the <code>thd</code> object may be modified by the builder.
46 In particular, the following members/methods can be set/called,
47 depending on the function called and the function possible side effects.
48 <ul>
49 <li><code>thd->lex->binlog_row_based_if_mixed</code></li>
50 <li><code>thd->lex->current_context()</code></li>
51 <li><code>thd->lex->safe_to_cache_query</code></li>
52 <li><code>thd->lex->uncacheable(UNCACHEABLE_SIDEEFFECT)</code></li>
53 <li><code>thd->lex->uncacheable(UNCACHEABLE_RAND)</code></li>
54 <li><code>thd->lex->add_time_zone_tables_to_query_tables(thd)</code></li>
55 </ul>
56 @param thd The current thread
57 @param name The function name
58 @param item_list The list of arguments to the function, can be NULL
59 @return An item representing the parsed function call, or NULL
60 */
61 virtual Item *create_func(THD *thd, LEX_CSTRING *name, List<Item> *item_list) = 0;
62
63protected:
64 /** Constructor */
65 Create_func() {}
66 /** Destructor */
67 virtual ~Create_func() {}
68};
69
70
71/**
72 Adapter for native functions with a variable number of arguments.
73 The main use of this class is to discard the following calls:
74 <code>foo(expr1 AS name1, expr2 AS name2, ...)</code>
75 which are syntactically correct (the syntax can refer to a UDF),
76 but semantically invalid for native functions.
77*/
78
79class Create_native_func : public Create_func
80{
81public:
82 virtual Item *create_func(THD *thd, LEX_CSTRING *name,
83 List<Item> *item_list);
84
85 /**
86 Builder method, with no arguments.
87 @param thd The current thread
88 @param name The native function name
89 @param item_list The function parameters, none of which are named
90 @return An item representing the function call
91 */
92 virtual Item *create_native(THD *thd, LEX_CSTRING *name,
93 List<Item> *item_list) = 0;
94
95protected:
96 /** Constructor. */
97 Create_native_func() {}
98 /** Destructor. */
99 virtual ~Create_native_func() {}
100};
101
102
103/**
104 Function builder for qualified functions.
105 This builder is used with functions call using a qualified function name
106 syntax, as in <code>db.func(expr, expr, ...)</code>.
107*/
108
109class Create_qfunc : public Create_func
110{
111public:
112 /**
113 The builder create method, for unqualified functions.
114 This builder will use the current database for the database name.
115 @param thd The current thread
116 @param name The function name
117 @param item_list The list of arguments to the function, can be NULL
118 @return An item representing the parsed function call
119 */
120 virtual Item *create_func(THD *thd, LEX_CSTRING *name,
121 List<Item> *item_list);
122
123 /**
124 The builder create method, for qualified functions.
125 @param thd The current thread
126 @param db The database name
127 @param name The function name
128 @param use_explicit_name Should the function be represented as 'db.name'?
129 @param item_list The list of arguments to the function, can be NULL
130 @return An item representing the parsed function call
131 */
132 virtual Item *create_with_db(THD *thd, LEX_CSTRING *db, LEX_CSTRING *name,
133 bool use_explicit_name,
134 List<Item> *item_list) = 0;
135
136protected:
137 /** Constructor. */
138 Create_qfunc() {}
139 /** Destructor. */
140 virtual ~Create_qfunc() {}
141};
142
143
144/**
145 Find the native function builder associated with a given function name.
146 @param thd The current thread
147 @param name The native function name
148 @return The native function builder associated with the name, or NULL
149*/
150extern Create_func *find_native_function_builder(THD *thd,
151 const LEX_CSTRING *name);
152
153
154/**
155 Find the function builder for qualified functions.
156 @param thd The current thread
157 @return A function builder for qualified functions
158*/
159extern Create_qfunc * find_qualified_function_builder(THD *thd);
160
161
162#ifdef HAVE_DLOPEN
163/**
164 Function builder for User Defined Functions.
165*/
166
167class Create_udf_func : public Create_func
168{
169public:
170 virtual Item *create_func(THD *thd, LEX_CSTRING *name,
171 List<Item> *item_list);
172
173 /**
174 The builder create method, for User Defined Functions.
175 @param thd The current thread
176 @param fct The User Defined Function metadata
177 @param item_list The list of arguments to the function, can be NULL
178 @return An item representing the parsed function call
179 */
180 Item *create(THD *thd, udf_func *fct, List<Item> *item_list);
181
182 /** Singleton. */
183 static Create_udf_func s_singleton;
184
185protected:
186 /** Constructor. */
187 Create_udf_func() {}
188 /** Destructor. */
189 virtual ~Create_udf_func() {}
190};
191#endif
192
193
194Item *create_temporal_literal(THD *thd,
195 const char *str, size_t length,
196 CHARSET_INFO *cs,
197 enum_field_types type,
198 bool send_error);
199inline
200Item *create_temporal_literal(THD *thd, const String *str,
201 enum_field_types type,
202 bool send_error)
203{
204 return create_temporal_literal(thd,
205 str->ptr(), str->length(), str->charset(),
206 type, send_error);
207}
208
209struct Native_func_registry
210{
211 LEX_CSTRING name;
212 Create_func *builder;
213};
214
215int item_create_init();
216int item_create_append(Native_func_registry array[]);
217void item_create_cleanup();
218
219Item *create_func_dyncol_create(THD *thd, List<DYNCALL_CREATE_DEF> &list);
220Item *create_func_dyncol_add(THD *thd, Item *str,
221 List<DYNCALL_CREATE_DEF> &list);
222Item *create_func_dyncol_delete(THD *thd, Item *str, List<Item> &nums);
223Item *create_func_dyncol_get(THD *thd, Item *num, Item *str,
224 const Type_handler *handler,
225 const char *c_len, const char *c_dec,
226 CHARSET_INFO *cs);
227Item *create_func_dyncol_json(THD *thd, Item *str);
228#endif
229
230