MySQL  8.0.27
Source Code Documentation
item_create.h
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19  You should have received a copy of the GNU General Public License
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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 /**
29  @file sql/item_create.h
30  Builder for SQL functions.
31 */
32 
33 #include <cstddef>
34 
35 #include "lex_string.h"
36 #include "my_inttypes.h" // uint
37 #include "sql/parse_location.h" // POS
38 
39 /**
40  @addtogroup GROUP_PARSER
41  @{
42 */
43 
44 class Item;
45 class PT_item_list;
46 class THD;
47 struct Cast_type;
48 struct CHARSET_INFO;
49 struct udf_func;
50 enum enum_field_types : int;
51 enum class Json_on_response_type : uint16;
52 
53 /* For type casts */
54 
55 enum Cast_target : unsigned char {
74 };
75 
76 /**
77  Public function builder interface.
78  The parser (sql/sql_yacc.yy) uses a factory / builder pattern to
79  construct an <code>Item</code> object for each function call.
80  All the concrete function builders implements this interface,
81  either directly or indirectly with some adapter helpers.
82  Keeping the function creation separated from the bison grammar allows
83  to simplify the parser, and avoid the need to introduce a new token
84  for each function, which has undesirable side effects in the grammar.
85 */
86 
87 class Create_func {
88  public:
89  /**
90  The builder create method.
91  Given the function name and list or arguments, this method creates
92  an <code>Item</code> that represents the function call.
93  In case or errors, a NULL item is returned, and an error is reported.
94  Note that the <code>thd</code> object may be modified by the builder.
95  In particular, the following members/methods can be set/called,
96  depending on the function called and the function possible side effects.
97  <ul>
98  <li><code>thd->lex->binlog_row_based_if_mixed</code></li>
99  <li><code>thd->lex->current_context()</code></li>
100  <li><code>thd->lex->safe_to_cache_query</code></li>
101  <li><code>thd->lex->uncacheable(UNCACHEABLE_SIDEEFFECT)</code></li>
102  <li><code>thd->lex->uncacheable(UNCACHEABLE_RAND)</code></li>
103  <li><code>thd->lex->add_time_zone_tables_to_query_tables(thd)</code></li>
104  </ul>
105  @param thd The current thread
106  @param name The function name
107  @param item_list The list of arguments to the function, can be NULL
108  @return An item representing the parsed function call, or NULL
109  */
111  PT_item_list *item_list) = 0;
112 
113  protected:
114  Create_func() = default;
115  virtual ~Create_func() = default;
116 };
117 
118 /**
119  Function builder for qualified functions.
120  This builder is used with functions call using a qualified function name
121  syntax, as in <code>db.func(expr, expr, ...)</code>.
122 */
123 
124 class Create_qfunc : public Create_func {
125  public:
126  /**
127  The builder create method, for unqualified functions.
128  This builder will use the current database for the database name.
129  @param thd The current thread
130  @param name The function name
131  @param item_list The list of arguments to the function, can be NULL
132  @return An item representing the parsed function call
133  */
135  PT_item_list *item_list) override;
136 
137  /**
138  The builder create method, for qualified functions.
139  @param thd The current thread
140  @param db The database name or NULL_STR to use the default db name
141  @param name The function name
142  @param use_explicit_name Should the function be represented as 'db.name'?
143  @param item_list The list of arguments to the function, can be NULL
144  @return An item representing the parsed function call
145  */
146  virtual Item *create(THD *thd, LEX_STRING db, LEX_STRING name,
147  bool use_explicit_name, PT_item_list *item_list) = 0;
148 
149  protected:
150  /** Constructor. */
151  Create_qfunc() = default;
152  /** Destructor. */
153  ~Create_qfunc() override = default;
154 };
155 
156 /**
157  Find the native function builder associated with a given function name.
158 
159  @param name The native function name
160  @return The native function builder associated with the name, or NULL
161 */
163 
164 /**
165  Find the function builder for qualified functions.
166  @param thd The current thread
167  @return A function builder for qualified functions
168 */
170 
171 /**
172  Function builder for User Defined Functions.
173 */
174 
175 class Create_udf_func : public Create_func {
176  public:
178  PT_item_list *item_list) override;
179 
180  /**
181  The builder create method, for User Defined Functions.
182  @param thd The current thread
183  @param fct The User Defined Function metadata
184  @param item_list The list of arguments to the function, can be NULL
185  @return An item representing the parsed function call
186  */
187  Item *create(THD *thd, udf_func *fct, PT_item_list *item_list);
188 
189  /** Singleton. */
191 
192  protected:
193  /** Constructor. */
194  Create_udf_func() = default;
195  /** Destructor. */
196  ~Create_udf_func() override = default;
197 };
198 
199 /**
200  Builder for cast expressions.
201  @param thd The current thread
202  @param pos Location of casting expression
203  @param arg The item to cast
204  @param type the type casted into
205  @param as_array Cast to array
206 */
207 Item *create_func_cast(THD *thd, const POS &pos, Item *arg,
208  const Cast_type &type, bool as_array);
209 
210 Item *create_func_cast(THD *thd, const POS &pos, Item *a,
211  Cast_target cast_target, const CHARSET_INFO *cs_arg);
212 
213 /**
214  Creates an Item that represents a JSON_VALUE expression.
215 
216  @param thd thread handler
217  @param pos the location of the expression
218  @param arg the JSON input argument to the JSON_VALUE expression
219  @param path the path to extract from the JSON document
220  @param type the target type of the JSON_VALUE expression
221  @param on_empty_type the type of the ON EMPTY clause
222  @param on_empty_default the default value specified in ON EMPTY, if any
223  @param on_error_type the type of the ON ERROR clause
224  @param on_error_default the default value specified in ON ERROR, if any
225  @return an Item on success, or nullptr on error
226 */
227 Item *create_func_json_value(THD *thd, const POS &pos, Item *arg, Item *path,
228  const Cast_type &type,
229  Json_on_response_type on_empty_type,
230  Item *on_empty_default,
231  Json_on_response_type on_error_type,
232  Item *on_error_default);
233 
234 Item *create_temporal_literal(THD *thd, const char *str, size_t length,
236  bool send_error);
237 
238 /**
239  Load the hash table for native functions.
240  Note: this code is not thread safe, and is intended to be used at server
241  startup only (before going multi-threaded)
242 
243  @retval false OK.
244  @retval true An exception was caught.
245 */
246 bool item_create_init();
247 
248 /**
249  Empty the hash table for native functions.
250  Note: this code is not thread safe, and is intended to be used at server
251  shutdown only (after thread requests have been executed).
252 */
253 void item_create_cleanup();
254 
255 /**
256  @} (end of group GROUP_PARSER)
257 */
258 
259 #endif
Public function builder interface.
Definition: item_create.h:87
virtual Item * create_func(THD *thd, LEX_STRING name, PT_item_list *item_list)=0
The builder create method.
Create_func()=default
virtual ~Create_func()=default
Function builder for qualified functions.
Definition: item_create.h:124
Create_qfunc()=default
Constructor.
~Create_qfunc() override=default
Destructor.
virtual Item * create(THD *thd, LEX_STRING db, LEX_STRING name, bool use_explicit_name, PT_item_list *item_list)=0
The builder create method, for qualified functions.
Function builder for User Defined Functions.
Definition: item_create.h:175
Create_udf_func()=default
Constructor.
~Create_udf_func() override=default
Destructor.
Base class that is used to represent any kind of expression in a relational query.
Definition: item.h:802
Wrapper class for an Item list head, used to allocate Item lists in the parser in a context-independe...
Definition: parse_tree_helpers.h:101
For each client connection we create a separate thread with THD serving as a thread/connection descri...
Definition: sql_class.h:821
char * pos
Definition: do_ctype.cc:76
enum_field_types
Column types for MySQL.
Definition: field_types.h:57
Create_func * find_native_function_builder(const LEX_STRING &lex_name)
Find the native function builder associated with a given function name.
Definition: item_create.cc:1768
bool item_create_init()
Load the hash table for native functions.
Definition: item_create.cc:1755
Item * create_func(THD *thd, LEX_STRING name, PT_item_list *item_list) override
The builder create method, for unqualified functions.
Definition: item_create.cc:1122
Item * create(THD *thd, udf_func *fct, PT_item_list *item_list)
The builder create method, for User Defined Functions.
Definition: item_create.cc:1136
Cast_target
Definition: item_create.h:55
Item * create_func_cast(THD *thd, const POS &pos, Item *a, Cast_target cast_target, const CHARSET_INFO *cs)
Definition: item_create.cc:1786
Item * create_func_json_value(THD *thd, const POS &pos, Item *arg, Item *path, const Cast_type &cast_type, Json_on_response_type on_empty_type, Item *on_empty_default, Json_on_response_type on_error_type, Item *on_error_default)
Creates an Item that represents a JSON_VALUE expression.
Definition: item_create.cc:2102
Create_qfunc * find_qualified_function_builder(THD *)
Find the function builder for qualified functions.
Definition: item_create.cc:1782
void item_create_cleanup()
Empty the hash table for native functions.
Definition: item_create.cc:1766
static Create_udf_func s_singleton
Singleton.
Definition: item_create.h:190
Item * create_func(THD *thd, LEX_STRING name, PT_item_list *item_list) override
The builder create method.
Definition: item_create.cc:1129
Item * create_temporal_literal(THD *thd, const char *str, size_t length, const CHARSET_INFO *cs, enum_field_types type, bool send_error)
Builder for datetime literals: TIME'00:00:00', DATE'2001-01-01', TIMESTAMP'2001-01-01 00:00:00'.
Definition: item_create.cc:2136
@ ITEM_CAST_SIGNED_INT
@ ITEM_CAST_MULTIPOINT
@ ITEM_CAST_GEOMETRYCOLLECTION
@ ITEM_CAST_MULTIPOLYGON
@ ITEM_CAST_LINESTRING
@ ITEM_CAST_UNSIGNED_INT
@ ITEM_CAST_MULTILINESTRING
Some integer typedefs for easier portability.
uint16_t uint16
Definition: my_inttypes.h:64
static char * path
Definition: mysqldump.cc:130
std::string str(const mysqlrouter::ConfigGenerator::Options::Endpoint &ep)
Definition: config_generator.cc:1056
Definition: commit_order_queue.h:33
bool length(const dd::Spatial_reference_system *srs, const Geometry *g1, double *length, bool *null) noexcept
Computes the length of linestrings and multilinestrings.
Definition: length.cc:75
required string type
Definition: replication_group_member_actions.proto:33
case opt name
Definition: sslopt-case.h:32
Definition: m_ctype.h:354
Definition: parser_yystype.h:180
Definition: mysql_lex_string.h:34
Bison "location" class.
Definition: parse_location.h:42
Definition: sql_udf.h:43
Json_on_response_type
Types of ON EMPTY/ON ERROR clauses for JSON_TABLE and JSON_VALUE.
Definition: table_function.h:191