diff options
Diffstat (limited to 'sql/item.h')
| -rw-r--r-- | sql/item.h | 93 |
1 files changed, 73 insertions, 20 deletions
diff --git a/sql/item.h b/sql/item.h index 69a6718a5a9..a169fc32a0b 100644 --- a/sql/item.h +++ b/sql/item.h @@ -98,7 +98,8 @@ public: COPY_STR_ITEM, FIELD_AVG_ITEM, DEFAULT_VALUE_ITEM, PROC_ITEM,COND_ITEM, REF_ITEM, FIELD_STD_ITEM, FIELD_VARIANCE_ITEM, INSERT_VALUE_ITEM, - SUBSELECT_ITEM, ROW_ITEM, CACHE_ITEM, TYPE_HOLDER}; + SUBSELECT_ITEM, ROW_ITEM, CACHE_ITEM, TYPE_HOLDER, + PARAM_ITEM}; enum cond_result { COND_UNDEF,COND_OK,COND_TRUE,COND_FALSE }; @@ -161,6 +162,31 @@ public: /* valXXX methods must return NULL or 0 or 0.0 if null_value is set. */ virtual double val()=0; virtual longlong val_int()=0; + /* + Return string representation of this item object. + + The argument to val_str() is an allocated buffer this or any + nested Item object can use to store return value of this method. + This buffer should only be used if the item itself doesn't have an + own String buffer. In case when the item maintains it's own string + buffer, it's preferrable to return it instead to minimize number of + mallocs/memcpys. + The caller of this method can modify returned string, but only in + case when it was allocated on heap, (is_alloced() is true). This + allows the caller to efficiently use a buffer allocated by a child + without having to allocate a buffer of it's own. The buffer, given + to val_str() as agrument, belongs to the caller and is later used + by the caller at it's own choosing. + A few implications from the above: + - unless you return a string object which only points to your buffer + but doesn't manages it you should be ready that it will be + modified. + - even for not allocated strings (is_alloced() == false) the caller + can change charset (see Item_func_{typecast/binary}. XXX: is this + a bug? + - still you should try to minimize data copying and return internal + object whenever possible. + */ virtual String *val_str(String*)=0; virtual Field *get_tmp_table_field() { return 0; } virtual Field *tmp_table_field(TABLE *t_arg) { return 0; } @@ -221,7 +247,7 @@ public: virtual Item *real_item() { return this; } virtual Item *get_tmp_table_item(THD *thd) { return copy_or_same(thd); } - CHARSET_INFO *default_charset() const; + static CHARSET_INFO *default_charset(); virtual CHARSET_INFO *compare_collation() { return NULL; } virtual bool walk(Item_processor processor, byte *arg) @@ -409,17 +435,11 @@ class Item_field :public Item_ident void set_field(Field *field); public: Field *field,*result_field; -#ifndef DBUG_OFF - bool double_fix; -#endif Item_field(const char *db_par,const char *table_name_par, const char *field_name_par) :Item_ident(db_par,table_name_par,field_name_par), field(0), result_field(0) -#ifndef DBUG_OFF - ,double_fix(0) -#endif { collation.set(DERIVATION_IMPLICIT); } // Constructor need to process subselect with temporary tables (see Item) Item_field(THD *thd, Item_field *item); @@ -459,6 +479,7 @@ public: bool is_null() { return field->is_null(); } Item *get_tmp_table_item(THD *thd); void cleanup(); + inline uint32 max_disp_length() { return field->max_length(); } friend class Item_default_value; friend class Item_insert_value; friend class st_select_lex_unit; @@ -492,19 +513,33 @@ public: void print(String *str) { str->append("NULL", 4); } }; + +/* Item represents one placeholder ('?') of prepared statement */ + class Item_param :public Item { -public: +public: enum enum_item_param_state { NO_VALUE, NULL_VALUE, INT_VALUE, REAL_VALUE, STRING_VALUE, TIME_VALUE, LONG_DATA_VALUE } state; + /* + A buffer for string and long data values. Historically all allocated + values returned from val_str() were treated as eligible to + modification. I. e. in some cases Item_func_concat can append it's + second argument to return value of the first one. Because of that we + can't return the original buffer holding string data from val_str(), + and have to have one buffer for data and another just pointing to + the data. This is the latter one and it's returned from val_str(). + Can not be declared inside the union as it's not a POD type. + */ + String str_value_ptr; union { - longlong integer; - double real; + longlong integer; + double real; /* Character sets conversion info for string values. Character sets of client and connection defined at bind time are used @@ -517,7 +552,7 @@ public: /* This points at character set of connection if conversion to it is required (i. e. if placeholder typecode is not BLOB). - Otherwise it's equal to character_set_client (to simplify + Otherwise it's equal to character_set_client (to simplify check in convert_str_value()). */ CHARSET_INFO *final_character_set_of_str_value; @@ -528,22 +563,33 @@ public: /* Cached values for virtual methods to save us one switch. */ enum Item_result item_result_type; enum Type item_type; - /* + + /* + Used when this item is used in a temporary table. + This is NOT placeholder metadata sent to client, as this value + is assigned after sending metadata (in setup_one_conversion_function). + For example in case of 'SELECT ?' you'll get MYSQL_TYPE_STRING both + in result set and placeholders metadata, no matter what type you will + supply for this placeholder in mysql_stmt_execute. + */ + enum enum_field_types param_type; + /* Offset of placeholder inside statement text. Used to create no-placeholders version of this statement for the binary log. - */ + */ uint pos_in_query; Item_param(uint pos_in_query_arg); enum Item_result result_type () const { return item_result_type; } enum Type type() const { return item_type; } - enum_field_types field_type() const { return MYSQL_TYPE_STRING; } + enum_field_types field_type() const { return param_type; } double val(); longlong val_int(); String *val_str(String*); bool get_time(TIME *tm); + bool get_date(TIME *tm, uint fuzzydate); int save_in_field(Field *field, bool no_conversions); void set_null(); @@ -552,6 +598,7 @@ public: bool set_str(const char *str, ulong length); bool set_longdata(const char *str, ulong length); void set_time(TIME *tm, timestamp_type type, uint32 max_length_arg); + bool set_from_user_var(THD *thd, const user_var_entry *entry); void reset(); /* Assign placeholder value from bind data. @@ -564,16 +611,18 @@ public: const String *query_val_str(String *str) const; bool convert_str_value(THD *thd); - + Item *new_item() { return new Item_param(pos_in_query); } - /* - If value for parameter was not set we treat it as non-const - so noone will use parameters value in fix_fields still + /* + If value for parameter was not set we treat it as non-const + so noone will use parameters value in fix_fields still parameter is constant during execution. */ virtual table_map used_tables() const { return state != NO_VALUE ? (table_map)0 : PARAM_TABLE_BIT; } void print(String *str) { str->append('?'); } + /* parameter never equal to other parameter of other item */ + bool eq(const Item *item, bool binary_cmp) const { return 0; } }; class Item_int :public Item_num @@ -871,7 +920,10 @@ public: void save_org_in_field(Field *field) { (*ref)->save_org_in_field(field); } enum Item_result result_type () const { return (*ref)->result_type(); } enum_field_types field_type() const { return (*ref)->field_type(); } - table_map used_tables() const { return (*ref)->used_tables(); } + table_map used_tables() const + { + return depended_from ? OUTER_REF_TABLE_BIT : (*ref)->used_tables(); + } void set_result_field(Field *field) { result_field= field; } bool is_result_field() { return 1; } void save_in_result_field(bool no_conversions) @@ -1250,6 +1302,7 @@ public: String *val_str(String*); bool join_types(THD *thd, Item *); Field *example() { return field_example; } + static uint32 real_length(Item *item); void cleanup() { DBUG_ENTER("Item_type_holder::cleanup"); |