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mariadb/sql/item_cmpfunc.cc
unknown a475ed7c6b Bug#24532 (The return data type of IS TRUE is different from similar 
operations)

Before this change, the boolean predicates:
- X IS TRUE,
- X IS NOT TRUE,
- X IS FALSE,
- X IS NOT FALSE
were implemented by expanding the Item tree in the parser, by using a
construct like:
Item_func_if(Item_func_ifnull(X, <value>), <value>, <value>)

Each <value> was a constant integer, either 0 or 1.

A bug in the implementation of the function IF(a, b, c), in
Item_func_if::fix_length_and_dec(), would cause the following :

When the arguments b and c are both unsigned, the result type of the
function was signed, instead of unsigned.

When the result of the if function is signed, space for the sign could be
counted twice (in the max() expression for a signed argument, and in the
total), causing the member max_length to be too high.

An effect of this is that the final type of IF(x, int(1), int(1)) would be
int(2) instead of int(1).

With this fix, the problems found in Item_func_if::fix_length_and_dec()
have been fixed.

While it's semantically correct to represent 'X IS TRUE' with
Item_func_if(Item_func_ifnull(X, <value>), <value>, <value>),
there are however more problems with this construct.

a)
Building the parse tree involves :
- creating 5 Item instances (3 ints, 1 ifnull, 1 if),
- creating each Item calls my_pthread_getspecific_ptr() once in the operator
  new(size), and a second time in the Item::Item() constructor, resulting
  in a total of 10 calls to get the current thread.
Evaluating the expression involves evaluating up to 4 nodes at runtime.
This representation could be greatly simplified and improved.

b)
Transforming the parse tree internally with if(ifnull(...)) is fine as long
as this transformation is internal to the server implementation.
With views however, the result of the parse tree is later exposed by the
::print() functions, and stored as part of the view definition.
Doing this has long term consequences:

1)
The original semantic 'X IS TRUE' is lost, and replaced by the
if(ifnull(...)) expression. As a result, SHOW CREATE VIEW does not restore
the original code.

2)
Should a future version of MySQL implement the SQL BOOLEAN data type for
example, views created today using 'X IS NULL' can be exported using
mysqldump, and imported again. Such views would be converted correctly and
automatically to use a BOOLEAN column in the future version.
With 'X IS TRUE' and the current implementations, views using these
"boolean" predicates would not be converted during the export/import, and
would use integer columns instead.
The difference traces back to how SHOW CREATE VIEW preserves 'X IS NULL' but
does not preserve the 'X IS TRUE' semantic.

With this fix, internal representation of 'X IS TRUE' booleans predicates
has changed, so that:
- dedicated Item classes are created for each predicate,
- only 1 Item is created to represent 1 predicate
- my_pthread_getspecific_ptr() is invoked 1 time instead of 10
- SHOW CREATE VIEW preserves the original semantic, and prints 'X IS TRUE'.

Note that, because of the fix in Item_func_if, views created before this fix
will:
- correctly use a int(1) type instead of int(2) for boolean predicates,
- incorrectly print the if(ifnull(...), ...) expression in SHOW CREATE VIEW,
since the original semantic (X IS TRUE) has been lost.
- except for the syntax used in SHOW CREATE VIEW, these views will operate
properly, no action is needed.

Views created after this fix will operate correctly, and will preserve the
original code semantic in SHOW CREATE VIEW.


mysql-test/r/func_if.result:
  IF(x, unsigned, unsigned) should be unsigned.
mysql-test/r/view.result:
  Preserve the semantic of 'X IS [NOT] (TRUE|FALSE)' boolean predicates.
mysql-test/t/func_if.test:
  IF(x, unsigned, unsigned) should be unsigned.
mysql-test/t/view.test:
  Preserve the semantic of 'X IS [NOT] (TRUE|FALSE)' boolean predicates.
sql/item_cmpfunc.cc:
  Preserve the semantic of 'X IS [NOT] (TRUE|FALSE)' boolean predicates.
  IF(x, unsigned, unsigned) should be unsigned.
sql/item_cmpfunc.h:
  Preserve the semantic of 'X IS [NOT] (TRUE|FALSE)' boolean predicates.
sql/sql_yacc.yy:
  Preserve the semantic of 'X IS [NOT] (TRUE|FALSE)' boolean predicates.
2007-02-12 13:59:29 -07:00

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/* Copyright (C) 2000-2006 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* This file defines all compare functions */
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include "mysql_priv.h"
#include <m_ctype.h>
#include "sql_select.h"
static bool convert_constant_item(THD *thd, Field *field, Item **item);
static Item_result item_store_type(Item_result a,Item_result b)
{
if (a == STRING_RESULT || b == STRING_RESULT)
return STRING_RESULT;
else if (a == REAL_RESULT || b == REAL_RESULT)
return REAL_RESULT;
else if (a == DECIMAL_RESULT || b == DECIMAL_RESULT)
return DECIMAL_RESULT;
else
return INT_RESULT;
}
static void agg_result_type(Item_result *type, Item **items, uint nitems)
{
Item **item, **item_end;
*type= STRING_RESULT;
/* Skip beginning NULL items */
for (item= items, item_end= item + nitems; item < item_end; item++)
{
if ((*item)->type() != Item::NULL_ITEM)
{
*type= (*item)->result_type();
item++;
break;
}
}
/* Combine result types. Note: NULL items don't affect the result */
for (; item < item_end; item++)
{
if ((*item)->type() != Item::NULL_ITEM)
*type= item_store_type(type[0], (*item)->result_type());
}
}
/*
Aggregates result types from the array of items.
SYNOPSIS:
agg_cmp_type()
thd thread handle
type [out] the aggregated type
items array of items to aggregate the type from
nitems number of items in the array
DESCRIPTION
This function aggregates result types from the array of items. Found type
supposed to be used later for comparison of values of these items.
Aggregation itself is performed by the item_cmp_type() function.
*/
static void agg_cmp_type(THD *thd, Item_result *type, Item **items, uint nitems)
{
uint i;
type[0]= items[0]->result_type();
for (i= 1 ; i < nitems ; i++)
type[0]= item_cmp_type(type[0], items[i]->result_type());
}
static void my_coll_agg_error(DTCollation &c1, DTCollation &c2,
const char *fname)
{
my_error(ER_CANT_AGGREGATE_2COLLATIONS, MYF(0),
c1.collation->name,c1.derivation_name(),
c2.collation->name,c2.derivation_name(),
fname);
}
Item_bool_func2* Eq_creator::create(Item *a, Item *b) const
{
return new Item_func_eq(a, b);
}
Item_bool_func2* Ne_creator::create(Item *a, Item *b) const
{
return new Item_func_ne(a, b);
}
Item_bool_func2* Gt_creator::create(Item *a, Item *b) const
{
return new Item_func_gt(a, b);
}
Item_bool_func2* Lt_creator::create(Item *a, Item *b) const
{
return new Item_func_lt(a, b);
}
Item_bool_func2* Ge_creator::create(Item *a, Item *b) const
{
return new Item_func_ge(a, b);
}
Item_bool_func2* Le_creator::create(Item *a, Item *b) const
{
return new Item_func_le(a, b);
}
/*
Test functions
Most of these returns 0LL if false and 1LL if true and
NULL if some arg is NULL.
*/
longlong Item_func_not::val_int()
{
DBUG_ASSERT(fixed == 1);
bool value= args[0]->val_bool();
null_value=args[0]->null_value;
return ((!null_value && value == 0) ? 1 : 0);
}
/*
special NOT for ALL subquery
*/
longlong Item_func_not_all::val_int()
{
DBUG_ASSERT(fixed == 1);
bool value= args[0]->val_bool();
/*
return TRUE if there was records in underlying select in max/min
optimization (ALL subquery)
*/
if (empty_underlying_subquery())
return 1;
null_value= args[0]->null_value;
return ((!null_value && value == 0) ? 1 : 0);
}
bool Item_func_not_all::empty_underlying_subquery()
{
return ((test_sum_item && !test_sum_item->any_value()) ||
(test_sub_item && !test_sub_item->any_value()));
}
void Item_func_not_all::print(String *str)
{
if (show)
Item_func::print(str);
else
args[0]->print(str);
}
/*
Special NOP (No OPeration) for ALL subquery it is like Item_func_not_all
(return TRUE if underlying subquery do not return rows) but if subquery
returns some rows it return same value as argument (TRUE/FALSE).
*/
longlong Item_func_nop_all::val_int()
{
DBUG_ASSERT(fixed == 1);
longlong value= args[0]->val_int();
/*
return FALSE if there was records in underlying select in max/min
optimization (SAME/ANY subquery)
*/
if (empty_underlying_subquery())
return 0;
null_value= args[0]->null_value;
return (null_value || value == 0) ? 0 : 1;
}
/*
Convert a constant item to an int and replace the original item
SYNOPSIS
convert_constant_item()
thd thread handle
field item will be converted using the type of this field
item [in/out] reference to the item to convert
DESCRIPTION
The function converts a constant expression or string to an integer.
On successful conversion the original item is substituted for the
result of the item evaluation.
This is done when comparing DATE/TIME of different formats and
also when comparing bigint to strings (in which case strings
are converted to bigints).
NOTES
This function is called only at prepare stage.
As all derived tables are filled only after all derived tables
are prepared we do not evaluate items with subselects here because
they can contain derived tables and thus we may attempt to use a
table that has not been populated yet.
RESULT VALUES
0 Can't convert item
1 Item was replaced with an integer version of the item
*/
static bool convert_constant_item(THD *thd, Field *field, Item **item)
{
if (!(*item)->with_subselect && (*item)->const_item())
{
/* For comparison purposes allow invalid dates like 2000-01-32 */
ulong orig_sql_mode= thd->variables.sql_mode;
thd->variables.sql_mode|= MODE_INVALID_DATES;
if (!(*item)->save_in_field(field, 1) && !((*item)->null_value))
{
Item *tmp=new Item_int_with_ref(field->val_int(), *item,
test(field->flags & UNSIGNED_FLAG));
thd->variables.sql_mode= orig_sql_mode;
if (tmp)
thd->change_item_tree(item, tmp);
return 1; // Item was replaced
}
thd->variables.sql_mode= orig_sql_mode;
}
return 0;
}
void Item_bool_func2::fix_length_and_dec()
{
max_length= 1; // Function returns 0 or 1
THD *thd= current_thd;
/*
As some compare functions are generated after sql_yacc,
we have to check for out of memory conditions here
*/
if (!args[0] || !args[1])
return;
/*
We allow to convert to Unicode character sets in some cases.
The conditions when conversion is possible are:
- arguments A and B have different charsets
- A wins according to coercibility rules
- character set of A is superset for character set of B
If all of the above is true, then it's possible to convert
B into the character set of A, and then compare according
to the collation of A.
*/
DTCollation coll;
if (args[0]->result_type() == STRING_RESULT &&
args[1]->result_type() == STRING_RESULT &&
agg_arg_charsets(coll, args, 2, MY_COLL_CMP_CONV, 1))
return;
args[0]->cmp_context= args[1]->cmp_context=
item_cmp_type(args[0]->result_type(), args[1]->result_type());
// Make a special case of compare with fields to get nicer DATE comparisons
if (functype() == LIKE_FUNC) // Disable conversion in case of LIKE function.
{
set_cmp_func();
return;
}
if (!thd->is_context_analysis_only())
{
Item *real_item= args[0]->real_item();
if (real_item->type() == FIELD_ITEM)
{
Field *field=((Item_field*) real_item)->field;
if (field->can_be_compared_as_longlong())
{
if (convert_constant_item(thd, field,&args[1]))
{
cmp.set_cmp_func(this, tmp_arg, tmp_arg+1,
INT_RESULT); // Works for all types.
args[0]->cmp_context= args[1]->cmp_context= INT_RESULT;
return;
}
}
}
real_item= args[1]->real_item();
if (real_item->type() == FIELD_ITEM /* && !real_item->const_item() */)
{
Field *field=((Item_field*) real_item)->field;
if (field->can_be_compared_as_longlong())
{
if (convert_constant_item(thd, field,&args[0]))
{
cmp.set_cmp_func(this, tmp_arg, tmp_arg+1,
INT_RESULT); // Works for all types.
args[0]->cmp_context= args[1]->cmp_context= INT_RESULT;
return;
}
}
}
}
set_cmp_func();
}
int Arg_comparator::set_compare_func(Item_bool_func2 *item, Item_result type)
{
owner= item;
func= comparator_matrix[type]
[test(owner->functype() == Item_func::EQUAL_FUNC)];
switch (type) {
case ROW_RESULT:
{
uint n= (*a)->cols();
if (n != (*b)->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), n);
comparators= 0;
return 1;
}
if (!(comparators= new Arg_comparator[n]))
return 1;
for (uint i=0; i < n; i++)
{
if ((*a)->el(i)->cols() != (*b)->el(i)->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), (*a)->el(i)->cols());
return 1;
}
comparators[i].set_cmp_func(owner, (*a)->addr(i), (*b)->addr(i));
}
break;
}
case STRING_RESULT:
{
/*
We must set cmp_charset here as we may be called from for an automatic
generated item, like in natural join
*/
if (cmp_collation.set((*a)->collation, (*b)->collation) ||
cmp_collation.derivation == DERIVATION_NONE)
{
my_coll_agg_error((*a)->collation, (*b)->collation, owner->func_name());
return 1;
}
if (cmp_collation.collation == &my_charset_bin)
{
/*
We are using BLOB/BINARY/VARBINARY, change to compare byte by byte,
without removing end space
*/
if (func == &Arg_comparator::compare_string)
func= &Arg_comparator::compare_binary_string;
else if (func == &Arg_comparator::compare_e_string)
func= &Arg_comparator::compare_e_binary_string;
/*
As this is binary compassion, mark all fields that they can't be
transformed. Otherwise we would get into trouble with comparisons
like:
WHERE col= 'j' AND col LIKE BINARY 'j'
which would be transformed to:
WHERE col= 'j'
*/
(*a)->walk(&Item::set_no_const_sub, (byte*) 0);
(*b)->walk(&Item::set_no_const_sub, (byte*) 0);
}
break;
}
case INT_RESULT:
{
if (func == &Arg_comparator::compare_int_signed)
{
if ((*a)->unsigned_flag)
func= (((*b)->unsigned_flag)?
&Arg_comparator::compare_int_unsigned :
&Arg_comparator::compare_int_unsigned_signed);
else if ((*b)->unsigned_flag)
func= &Arg_comparator::compare_int_signed_unsigned;
}
else if (func== &Arg_comparator::compare_e_int)
{
if ((*a)->unsigned_flag ^ (*b)->unsigned_flag)
func= &Arg_comparator::compare_e_int_diff_signedness;
}
break;
}
case DECIMAL_RESULT:
case REAL_RESULT:
break;
default:
DBUG_ASSERT(0);
}
return 0;
}
int Arg_comparator::compare_string()
{
String *res1,*res2;
if ((res1= (*a)->val_str(&owner->tmp_value1)))
{
if ((res2= (*b)->val_str(&owner->tmp_value2)))
{
owner->null_value= 0;
return sortcmp(res1,res2,cmp_collation.collation);
}
}
owner->null_value= 1;
return -1;
}
/*
Compare strings byte by byte. End spaces are also compared.
RETURN
< 0 *a < *b
0 *b == *b
> 0 *a > *b
*/
int Arg_comparator::compare_binary_string()
{
String *res1,*res2;
if ((res1= (*a)->val_str(&owner->tmp_value1)))
{
if ((res2= (*b)->val_str(&owner->tmp_value2)))
{
owner->null_value= 0;
uint res1_length= res1->length();
uint res2_length= res2->length();
int cmp= memcmp(res1->ptr(), res2->ptr(), min(res1_length,res2_length));
return cmp ? cmp : (int) (res1_length - res2_length);
}
}
owner->null_value= 1;
return -1;
}
/*
Compare strings, but take into account that NULL == NULL
*/
int Arg_comparator::compare_e_string()
{
String *res1,*res2;
res1= (*a)->val_str(&owner->tmp_value1);
res2= (*b)->val_str(&owner->tmp_value2);
if (!res1 || !res2)
return test(res1 == res2);
return test(sortcmp(res1, res2, cmp_collation.collation) == 0);
}
int Arg_comparator::compare_e_binary_string()
{
String *res1,*res2;
res1= (*a)->val_str(&owner->tmp_value1);
res2= (*b)->val_str(&owner->tmp_value2);
if (!res1 || !res2)
return test(res1 == res2);
return test(stringcmp(res1, res2) == 0);
}
int Arg_comparator::compare_real()
{
/*
Fix yet another manifestation of Bug#2338. 'Volatile' will instruct
gcc to flush double values out of 80-bit Intel FPU registers before
performing the comparison.
*/
volatile double val1, val2;
val1= (*a)->val_real();
if (!(*a)->null_value)
{
val2= (*b)->val_real();
if (!(*b)->null_value)
{
owner->null_value= 0;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_decimal()
{
my_decimal value1;
my_decimal *val1= (*a)->val_decimal(&value1);
if (!(*a)->null_value)
{
my_decimal value2;
my_decimal *val2= (*b)->val_decimal(&value2);
if (!(*b)->null_value)
{
owner->null_value= 0;
return my_decimal_cmp(val1, val2);
}
}
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_e_real()
{
double val1= (*a)->val_real();
double val2= (*b)->val_real();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(val1 == val2);
}
int Arg_comparator::compare_e_decimal()
{
my_decimal value1, value2;
my_decimal *val1= (*a)->val_decimal(&value1);
my_decimal *val2= (*b)->val_decimal(&value2);
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(my_decimal_cmp(val1, val2) == 0);
}
int Arg_comparator::compare_int_signed()
{
longlong val1= (*a)->val_int();
if (!(*a)->null_value)
{
longlong val2= (*b)->val_int();
if (!(*b)->null_value)
{
owner->null_value= 0;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
owner->null_value= 1;
return -1;
}
/*
Compare values as BIGINT UNSIGNED.
*/
int Arg_comparator::compare_int_unsigned()
{
ulonglong val1= (*a)->val_int();
if (!(*a)->null_value)
{
ulonglong val2= (*b)->val_int();
if (!(*b)->null_value)
{
owner->null_value= 0;
if (val1 < val2) return -1;
if (val1 == val2) return 0;
return 1;
}
}
owner->null_value= 1;
return -1;
}
/*
Compare signed (*a) with unsigned (*B)
*/
int Arg_comparator::compare_int_signed_unsigned()
{
longlong sval1= (*a)->val_int();
if (!(*a)->null_value)
{
ulonglong uval2= (ulonglong)(*b)->val_int();
if (!(*b)->null_value)
{
owner->null_value= 0;
if (sval1 < 0 || (ulonglong)sval1 < uval2)
return -1;
if ((ulonglong)sval1 == uval2)
return 0;
return 1;
}
}
owner->null_value= 1;
return -1;
}
/*
Compare unsigned (*a) with signed (*B)
*/
int Arg_comparator::compare_int_unsigned_signed()
{
ulonglong uval1= (ulonglong)(*a)->val_int();
if (!(*a)->null_value)
{
longlong sval2= (*b)->val_int();
if (!(*b)->null_value)
{
owner->null_value= 0;
if (sval2 < 0)
return 1;
if (uval1 < (ulonglong)sval2)
return -1;
if (uval1 == (ulonglong)sval2)
return 0;
return 1;
}
}
owner->null_value= 1;
return -1;
}
int Arg_comparator::compare_e_int()
{
longlong val1= (*a)->val_int();
longlong val2= (*b)->val_int();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return test(val1 == val2);
}
/*
Compare unsigned *a with signed *b or signed *a with unsigned *b.
*/
int Arg_comparator::compare_e_int_diff_signedness()
{
longlong val1= (*a)->val_int();
longlong val2= (*b)->val_int();
if ((*a)->null_value || (*b)->null_value)
return test((*a)->null_value && (*b)->null_value);
return (val1 >= 0) && test(val1 == val2);
}
int Arg_comparator::compare_row()
{
int res= 0;
bool was_null= 0;
(*a)->bring_value();
(*b)->bring_value();
uint n= (*a)->cols();
for (uint i= 0; i<n; i++)
{
res= comparators[i].compare();
if (owner->null_value)
{
// NULL was compared
if (owner->abort_on_null)
return -1; // We do not need correct NULL returning
was_null= 1;
owner->null_value= 0;
res= 0; // continue comparison (maybe we will meet explicit difference)
}
else if (res)
return res;
}
if (was_null)
{
/*
There was NULL(s) in comparison in some parts, but there was not
explicit difference in other parts, so we have to return NULL
*/
owner->null_value= 1;
return -1;
}
return 0;
}
int Arg_comparator::compare_e_row()
{
(*a)->bring_value();
(*b)->bring_value();
uint n= (*a)->cols();
for (uint i= 0; i<n; i++)
{
if (!comparators[i].compare())
return 0;
}
return 1;
}
void Item_func_truth::fix_length_and_dec()
{
maybe_null= 0;
null_value= 0;
decimals= 0;
max_length= 1;
}
void Item_func_truth::print(String *str)
{
str->append('(');
args[0]->print(str);
str->append(STRING_WITH_LEN(" is "));
if (! affirmative)
str->append(STRING_WITH_LEN("not "));
if (value)
str->append(STRING_WITH_LEN("true"));
else
str->append(STRING_WITH_LEN("false"));
str->append(')');
}
bool Item_func_truth::val_bool()
{
bool val= args[0]->val_bool();
if (args[0]->null_value)
{
/*
NULL val IS {TRUE, FALSE} --> FALSE
NULL val IS NOT {TRUE, FALSE} --> TRUE
*/
return (! affirmative);
}
if (affirmative)
{
/* {TRUE, FALSE} val IS {TRUE, FALSE} value */
return (val == value);
}
/* {TRUE, FALSE} val IS NOT {TRUE, FALSE} value */
return (val != value);
}
longlong Item_func_truth::val_int()
{
return (val_bool() ? 1 : 0);
}
bool Item_in_optimizer::fix_left(THD *thd, Item **ref)
{
if (!args[0]->fixed && args[0]->fix_fields(thd, args) ||
!cache && !(cache= Item_cache::get_cache(args[0]->result_type())))
return 1;
cache->setup(args[0]);
if (cache->cols() == 1)
{
if ((used_tables_cache= args[0]->used_tables()))
cache->set_used_tables(OUTER_REF_TABLE_BIT);
else
cache->set_used_tables(0);
}
else
{
uint n= cache->cols();
for (uint i= 0; i < n; i++)
{
if (args[0]->el(i)->used_tables())
((Item_cache *)cache->el(i))->set_used_tables(OUTER_REF_TABLE_BIT);
else
((Item_cache *)cache->el(i))->set_used_tables(0);
}
used_tables_cache= args[0]->used_tables();
}
not_null_tables_cache= args[0]->not_null_tables();
with_sum_func= args[0]->with_sum_func;
const_item_cache= args[0]->const_item();
return 0;
}
bool Item_in_optimizer::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if (fix_left(thd, ref))
return TRUE;
if (args[0]->maybe_null)
maybe_null=1;
if (!args[1]->fixed && args[1]->fix_fields(thd, args+1))
return TRUE;
Item_in_subselect * sub= (Item_in_subselect *)args[1];
if (args[0]->cols() != sub->engine->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), args[0]->cols());
return TRUE;
}
if (args[1]->maybe_null)
maybe_null=1;
with_sum_func= with_sum_func || args[1]->with_sum_func;
used_tables_cache|= args[1]->used_tables();
not_null_tables_cache|= args[1]->not_null_tables();
const_item_cache&= args[1]->const_item();
fixed= 1;
return FALSE;
}
longlong Item_in_optimizer::val_int()
{
DBUG_ASSERT(fixed == 1);
cache->store(args[0]);
if (cache->null_value)
{
if (((Item_in_subselect*)args[1])->is_top_level_item())
{
/*
We're evaluating "NULL IN (SELECT ...)". The result can be NULL or
FALSE, and we can return one instead of another. Just return NULL.
*/
null_value= 1;
}
else
{
if (!((Item_in_subselect*)args[1])->is_correlated &&
result_for_null_param != UNKNOWN)
{
/* Use cached value from previous execution */
null_value= result_for_null_param;
}
else
{
/*
We're evaluating "NULL IN (SELECT ...)". The result is:
FALSE if SELECT produces an empty set, or
NULL otherwise.
We disable the predicates we've pushed down into subselect, run the
subselect and see if it has produced any rows.
*/
((Item_in_subselect*)args[1])->enable_pushed_conds= FALSE;
longlong tmp= args[1]->val_bool_result();
result_for_null_param= null_value=
!((Item_in_subselect*)args[1])->engine->no_rows();
((Item_in_subselect*)args[1])->enable_pushed_conds= TRUE;
}
}
return 0;
}
bool tmp= args[1]->val_bool_result();
null_value= args[1]->null_value;
return tmp;
}
void Item_in_optimizer::keep_top_level_cache()
{
cache->keep_array();
save_cache= 1;
}
void Item_in_optimizer::cleanup()
{
DBUG_ENTER("Item_in_optimizer::cleanup");
Item_bool_func::cleanup();
if (!save_cache)
cache= 0;
DBUG_VOID_RETURN;
}
bool Item_in_optimizer::is_null()
{
cache->store(args[0]);
return (null_value= (cache->null_value || args[1]->is_null()));
}
longlong Item_func_eq::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value == 0 ? 1 : 0;
}
/* Same as Item_func_eq, but NULL = NULL */
void Item_func_equal::fix_length_and_dec()
{
Item_bool_func2::fix_length_and_dec();
maybe_null=null_value=0;
}
longlong Item_func_equal::val_int()
{
DBUG_ASSERT(fixed == 1);
return cmp.compare();
}
longlong Item_func_ne::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value != 0 && !null_value ? 1 : 0;
}
longlong Item_func_ge::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value >= 0 ? 1 : 0;
}
longlong Item_func_gt::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value > 0 ? 1 : 0;
}
longlong Item_func_le::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value <= 0 && !null_value ? 1 : 0;
}
longlong Item_func_lt::val_int()
{
DBUG_ASSERT(fixed == 1);
int value= cmp.compare();
return value < 0 && !null_value ? 1 : 0;
}
longlong Item_func_strcmp::val_int()
{
DBUG_ASSERT(fixed == 1);
String *a=args[0]->val_str(&tmp_value1);
String *b=args[1]->val_str(&tmp_value2);
if (!a || !b)
{
null_value=1;
return 0;
}
int value= sortcmp(a,b,cmp.cmp_collation.collation);
null_value=0;
return !value ? 0 : (value < 0 ? (longlong) -1 : (longlong) 1);
}
void Item_func_interval::fix_length_and_dec()
{
use_decimal_comparison= (row->el(0)->result_type() == DECIMAL_RESULT) ||
(row->el(0)->result_type() == INT_RESULT);
if (row->cols() > 8)
{
bool consts=1;
for (uint i=1 ; consts && i < row->cols() ; i++)
{
consts&= row->el(i)->const_item();
}
if (consts &&
(intervals=
(interval_range*) sql_alloc(sizeof(interval_range)*(row->cols()-1))))
{
if (use_decimal_comparison)
{
for (uint i=1 ; i < row->cols(); i++)
{
Item *el= row->el(i);
interval_range *range= intervals + (i-1);
if ((el->result_type() == DECIMAL_RESULT) ||
(el->result_type() == INT_RESULT))
{
range->type= DECIMAL_RESULT;
range->dec.init();
my_decimal *dec= el->val_decimal(&range->dec);
if (dec != &range->dec)
{
range->dec= *dec;
range->dec.fix_buffer_pointer();
}
}
else
{
range->type= REAL_RESULT;
range->dbl= el->val_real();
}
}
}
else
{
for (uint i=1 ; i < row->cols(); i++)
{
intervals[i-1].dbl= row->el(i)->val_real();
}
}
}
}
maybe_null= 0;
max_length= 2;
used_tables_cache|= row->used_tables();
not_null_tables_cache= row->not_null_tables();
with_sum_func= with_sum_func || row->with_sum_func;
const_item_cache&= row->const_item();
}
/*
Execute Item_func_interval()
SYNOPSIS
Item_func_interval::val_int()
NOTES
If we are doing a decimal comparison, we are
evaluating the first item twice.
RETURN
-1 if null value,
0 if lower than lowest
1 - arg_count-1 if between args[n] and args[n+1]
arg_count if higher than biggest argument
*/
longlong Item_func_interval::val_int()
{
DBUG_ASSERT(fixed == 1);
double value;
my_decimal dec_buf, *dec= NULL;
uint i;
if (use_decimal_comparison)
{
dec= row->el(0)->val_decimal(&dec_buf);
if (row->el(0)->null_value)
return -1;
my_decimal2double(E_DEC_FATAL_ERROR, dec, &value);
}
else
{
value= row->el(0)->val_real();
if (row->el(0)->null_value)
return -1;
}
if (intervals)
{ // Use binary search to find interval
uint start,end;
start= 0;
end= row->cols()-2;
while (start != end)
{
uint mid= (start + end + 1) / 2;
interval_range *range= intervals + mid;
my_bool cmp_result;
/*
The values in the range intervall may have different types,
Only do a decimal comparision of the first argument is a decimal
and we are comparing against a decimal
*/
if (dec && range->type == DECIMAL_RESULT)
cmp_result= my_decimal_cmp(&range->dec, dec) <= 0;
else
cmp_result= (range->dbl <= value);
if (cmp_result)
start= mid;
else
end= mid - 1;
}
interval_range *range= intervals+start;
return ((dec && range->type == DECIMAL_RESULT) ?
my_decimal_cmp(dec, &range->dec) < 0 :
value < range->dbl) ? 0 : start + 1;
}
for (i=1 ; i < row->cols() ; i++)
{
Item *el= row->el(i);
if (use_decimal_comparison &&
((el->result_type() == DECIMAL_RESULT) ||
(el->result_type() == INT_RESULT)))
{
my_decimal e_dec_buf, *e_dec= row->el(i)->val_decimal(&e_dec_buf);
if (my_decimal_cmp(e_dec, dec) > 0)
return i-1;
}
else if (row->el(i)->val_real() > value)
return i-1;
}
return i-1;
}
/*
Perform context analysis of a BETWEEN item tree
SYNOPSIS:
fix_fields()
thd reference to the global context of the query thread
tables list of all open tables involved in the query
ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
DESCRIPTION
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_between as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
NOTES
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
T0(e BETWEEN e1 AND e2) = union(T1(e),T1(e1),T1(e2))
T1(e BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
T0(e NOT BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
T1(e NOT BETWEEN e1 AND e2) = union(T1(e),intersection(T1(e1),T1(e2)))
RETURN
0 ok
1 got error
*/
bool Item_func_between::fix_fields(THD *thd, Item **ref)
{
if (Item_func_opt_neg::fix_fields(thd, ref))
return 1;
thd->lex->current_select->between_count++;
/* not_null_tables_cache == union(T1(e),T1(e1),T1(e2)) */
if (pred_level && !negated)
return 0;
/* not_null_tables_cache == union(T1(e), intersection(T1(e1),T1(e2))) */
not_null_tables_cache= (args[0]->not_null_tables() |
(args[1]->not_null_tables() &
args[2]->not_null_tables()));
return 0;
}
void Item_func_between::fix_length_and_dec()
{
max_length= 1;
THD *thd= current_thd;
/*
As some compare functions are generated after sql_yacc,
we have to check for out of memory conditions here
*/
if (!args[0] || !args[1] || !args[2])
return;
agg_cmp_type(thd, &cmp_type, args, 3);
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, 3, MY_COLL_CMP_CONV, 1))
return;
/*
Make a special case of compare with date/time and longlong fields.
They are compared as integers, so for const item this time-consuming
conversion can be done only once, not for every single comparison
*/
if (args[0]->type() == FIELD_ITEM &&
thd->lex->sql_command != SQLCOM_CREATE_VIEW &&
thd->lex->sql_command != SQLCOM_SHOW_CREATE)
{
Field *field=((Item_field*) args[0])->field;
if (field->can_be_compared_as_longlong())
{
/*
The following can't be recoded with || as convert_constant_item
changes the argument
*/
if (convert_constant_item(thd, field,&args[1]))
cmp_type=INT_RESULT; // Works for all types.
if (convert_constant_item(thd, field,&args[2]))
cmp_type=INT_RESULT; // Works for all types.
}
}
}
longlong Item_func_between::val_int()
{ // ANSI BETWEEN
DBUG_ASSERT(fixed == 1);
if (cmp_type == STRING_RESULT)
{
String *value,*a,*b;
value=args[0]->val_str(&value0);
if ((null_value=args[0]->null_value))
return 0;
a=args[1]->val_str(&value1);
b=args[2]->val_str(&value2);
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((sortcmp(value,a,cmp_collation.collation) >= 0 &&
sortcmp(value,b,cmp_collation.collation) <= 0) !=
negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
{
// Set to not null if false range.
null_value= sortcmp(value,b,cmp_collation.collation) <= 0;
}
else
{
// Set to not null if false range.
null_value= sortcmp(value,a,cmp_collation.collation) >= 0;
}
}
else if (cmp_type == INT_RESULT)
{
longlong value=args[0]->val_int(), a, b;
if ((null_value=args[0]->null_value))
return 0; /* purecov: inspected */
a=args[1]->val_int();
b=args[2]->val_int();
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((value >= a && value <= b) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
{
null_value= value <= b; // not null if false range.
}
else
{
null_value= value >= a;
}
}
else if (cmp_type == DECIMAL_RESULT)
{
my_decimal dec_buf, *dec= args[0]->val_decimal(&dec_buf),
a_buf, *a_dec, b_buf, *b_dec;
if ((null_value=args[0]->null_value))
return 0; /* purecov: inspected */
a_dec= args[1]->val_decimal(&a_buf);
b_dec= args[2]->val_decimal(&b_buf);
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((my_decimal_cmp(dec, a_dec) >= 0 &&
my_decimal_cmp(dec, b_dec) <= 0) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
null_value= (my_decimal_cmp(dec, b_dec) <= 0);
else
null_value= (my_decimal_cmp(dec, a_dec) >= 0);
}
else
{
double value= args[0]->val_real(),a,b;
if ((null_value=args[0]->null_value))
return 0; /* purecov: inspected */
a= args[1]->val_real();
b= args[2]->val_real();
if (!args[1]->null_value && !args[2]->null_value)
return (longlong) ((value >= a && value <= b) != negated);
if (args[1]->null_value && args[2]->null_value)
null_value=1;
else if (args[1]->null_value)
{
null_value= value <= b; // not null if false range.
}
else
{
null_value= value >= a;
}
}
return (longlong) (!null_value && negated);
}
void Item_func_between::print(String *str)
{
str->append('(');
args[0]->print(str);
if (negated)
str->append(STRING_WITH_LEN(" not"));
str->append(STRING_WITH_LEN(" between "));
args[1]->print(str);
str->append(STRING_WITH_LEN(" and "));
args[2]->print(str);
str->append(')');
}
void
Item_func_ifnull::fix_length_and_dec()
{
agg_result_type(&hybrid_type, args, 2);
maybe_null=args[1]->maybe_null;
decimals= max(args[0]->decimals, args[1]->decimals);
max_length= (hybrid_type == DECIMAL_RESULT || hybrid_type == INT_RESULT) ?
(max(args[0]->max_length - args[0]->decimals,
args[1]->max_length - args[1]->decimals) + decimals) :
max(args[0]->max_length, args[1]->max_length);
switch (hybrid_type) {
case STRING_RESULT:
agg_arg_charsets(collation, args, arg_count, MY_COLL_CMP_CONV, 1);
break;
case DECIMAL_RESULT:
case REAL_RESULT:
break;
case INT_RESULT:
decimals= 0;
break;
case ROW_RESULT:
default:
DBUG_ASSERT(0);
}
cached_field_type= args[0]->field_type();
if (cached_field_type != args[1]->field_type())
cached_field_type= Item_func::field_type();
}
uint Item_func_ifnull::decimal_precision() const
{
int max_int_part=max(args[0]->decimal_int_part(),args[1]->decimal_int_part());
return min(max_int_part + decimals, DECIMAL_MAX_PRECISION);
}
enum_field_types Item_func_ifnull::field_type() const
{
return cached_field_type;
}
Field *Item_func_ifnull::tmp_table_field(TABLE *table)
{
return tmp_table_field_from_field_type(table);
}
double
Item_func_ifnull::real_op()
{
DBUG_ASSERT(fixed == 1);
double value= args[0]->val_real();
if (!args[0]->null_value)
{
null_value=0;
return value;
}
value= args[1]->val_real();
if ((null_value=args[1]->null_value))
return 0.0;
return value;
}
longlong
Item_func_ifnull::int_op()
{
DBUG_ASSERT(fixed == 1);
longlong value=args[0]->val_int();
if (!args[0]->null_value)
{
null_value=0;
return value;
}
value=args[1]->val_int();
if ((null_value=args[1]->null_value))
return 0;
return value;
}
my_decimal *Item_func_ifnull::decimal_op(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
my_decimal *value= args[0]->val_decimal(decimal_value);
if (!args[0]->null_value)
{
null_value= 0;
return value;
}
value= args[1]->val_decimal(decimal_value);
if ((null_value= args[1]->null_value))
return 0;
return value;
}
String *
Item_func_ifnull::str_op(String *str)
{
DBUG_ASSERT(fixed == 1);
String *res =args[0]->val_str(str);
if (!args[0]->null_value)
{
null_value=0;
res->set_charset(collation.collation);
return res;
}
res=args[1]->val_str(str);
if ((null_value=args[1]->null_value))
return 0;
res->set_charset(collation.collation);
return res;
}
/*
Perform context analysis of an IF item tree
SYNOPSIS:
fix_fields()
thd reference to the global context of the query thread
tables list of all open tables involved in the query
ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
DESCRIPTION
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_if as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
NOTES
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
T0(IF(e,e1,e2) = T1(IF(e,e1,e2))
T1(IF(e,e1,e2)) = intersection(T1(e1),T1(e2))
RETURN
0 ok
1 got error
*/
bool
Item_func_if::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
args[0]->top_level_item();
if (Item_func::fix_fields(thd, ref))
return 1;
not_null_tables_cache= (args[1]->not_null_tables() &
args[2]->not_null_tables());
return 0;
}
void
Item_func_if::fix_length_and_dec()
{
maybe_null=args[1]->maybe_null || args[2]->maybe_null;
decimals= max(args[1]->decimals, args[2]->decimals);
unsigned_flag=args[1]->unsigned_flag && args[2]->unsigned_flag;
enum Item_result arg1_type=args[1]->result_type();
enum Item_result arg2_type=args[2]->result_type();
bool null1=args[1]->const_item() && args[1]->null_value;
bool null2=args[2]->const_item() && args[2]->null_value;
if (null1)
{
cached_result_type= arg2_type;
collation.set(args[2]->collation.collation);
}
else if (null2)
{
cached_result_type= arg1_type;
collation.set(args[1]->collation.collation);
}
else
{
agg_result_type(&cached_result_type, args+1, 2);
if (cached_result_type == STRING_RESULT)
{
if (agg_arg_charsets(collation, args+1, 2, MY_COLL_ALLOW_CONV, 1))
return;
}
else
{
collation.set(&my_charset_bin); // Number
}
}
if ((cached_result_type == DECIMAL_RESULT )
|| (cached_result_type == INT_RESULT))
{
int len1= args[1]->max_length - args[1]->decimals
- (args[1]->unsigned_flag ? 0 : 1);
int len2= args[2]->max_length - args[2]->decimals
- (args[2]->unsigned_flag ? 0 : 1);
max_length=max(len1, len2) + decimals + (unsigned_flag ? 0 : 1);
}
else
max_length= max(args[1]->max_length, args[2]->max_length);
}
uint Item_func_if::decimal_precision() const
{
int precision=(max(args[1]->decimal_int_part(),args[2]->decimal_int_part())+
decimals);
return min(precision, DECIMAL_MAX_PRECISION);
}
double
Item_func_if::val_real()
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
double value= arg->val_real();
null_value=arg->null_value;
return value;
}
longlong
Item_func_if::val_int()
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
longlong value=arg->val_int();
null_value=arg->null_value;
return value;
}
String *
Item_func_if::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
String *res=arg->val_str(str);
if (res)
res->set_charset(collation.collation);
null_value=arg->null_value;
return res;
}
my_decimal *
Item_func_if::val_decimal(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
Item *arg= args[0]->val_bool() ? args[1] : args[2];
my_decimal *value= arg->val_decimal(decimal_value);
null_value= arg->null_value;
return value;
}
void
Item_func_nullif::fix_length_and_dec()
{
Item_bool_func2::fix_length_and_dec();
maybe_null=1;
if (args[0]) // Only false if EOM
{
max_length=args[0]->max_length;
decimals=args[0]->decimals;
unsigned_flag= args[0]->unsigned_flag;
cached_result_type= args[0]->result_type();
if (cached_result_type == STRING_RESULT &&
agg_arg_charsets(collation, args, arg_count, MY_COLL_CMP_CONV, 1))
return;
}
}
/*
nullif () returns NULL if arguments are equal, else it returns the
first argument.
Note that we have to evaluate the first argument twice as the compare
may have been done with a different type than return value
*/
double
Item_func_nullif::val_real()
{
DBUG_ASSERT(fixed == 1);
double value;
if (!cmp.compare())
{
null_value=1;
return 0.0;
}
value= args[0]->val_real();
null_value=args[0]->null_value;
return value;
}
longlong
Item_func_nullif::val_int()
{
DBUG_ASSERT(fixed == 1);
longlong value;
if (!cmp.compare())
{
null_value=1;
return 0;
}
value=args[0]->val_int();
null_value=args[0]->null_value;
return value;
}
String *
Item_func_nullif::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
String *res;
if (!cmp.compare())
{
null_value=1;
return 0;
}
res=args[0]->val_str(str);
null_value=args[0]->null_value;
return res;
}
my_decimal *
Item_func_nullif::val_decimal(my_decimal * decimal_value)
{
DBUG_ASSERT(fixed == 1);
my_decimal *res;
if (!cmp.compare())
{
null_value=1;
return 0;
}
res= args[0]->val_decimal(decimal_value);
null_value= args[0]->null_value;
return res;
}
bool
Item_func_nullif::is_null()
{
return (null_value= (!cmp.compare() ? 1 : args[0]->null_value));
}
/*
CASE expression
Return the matching ITEM or NULL if all compares (including else) failed
*/
Item *Item_func_case::find_item(String *str)
{
String *first_expr_str, *tmp;
my_decimal *first_expr_dec, first_expr_dec_val;
longlong first_expr_int;
double first_expr_real;
char buff[MAX_FIELD_WIDTH];
String buff_str(buff,sizeof(buff),default_charset());
/* These will be initialized later */
LINT_INIT(first_expr_str);
LINT_INIT(first_expr_int);
LINT_INIT(first_expr_real);
LINT_INIT(first_expr_dec);
if (first_expr_num != -1)
{
switch (cmp_type)
{
case STRING_RESULT:
// We can't use 'str' here as this may be overwritten
if (!(first_expr_str= args[first_expr_num]->val_str(&buff_str)))
return else_expr_num != -1 ? args[else_expr_num] : 0; // Impossible
break;
case INT_RESULT:
first_expr_int= args[first_expr_num]->val_int();
if (args[first_expr_num]->null_value)
return else_expr_num != -1 ? args[else_expr_num] : 0;
break;
case REAL_RESULT:
first_expr_real= args[first_expr_num]->val_real();
if (args[first_expr_num]->null_value)
return else_expr_num != -1 ? args[else_expr_num] : 0;
break;
case DECIMAL_RESULT:
first_expr_dec= args[first_expr_num]->val_decimal(&first_expr_dec_val);
if (args[first_expr_num]->null_value)
return else_expr_num != -1 ? args[else_expr_num] : 0;
break;
case ROW_RESULT:
default:
// This case should never be chosen
DBUG_ASSERT(0);
break;
}
}
// Compare every WHEN argument with it and return the first match
for (uint i=0 ; i < ncases ; i+=2)
{
if (first_expr_num == -1)
{
// No expression between CASE and the first WHEN
if (args[i]->val_bool())
return args[i+1];
continue;
}
switch (cmp_type) {
case STRING_RESULT:
if ((tmp=args[i]->val_str(str))) // If not null
if (sortcmp(tmp,first_expr_str,cmp_collation.collation)==0)
return args[i+1];
break;
case INT_RESULT:
if (args[i]->val_int()==first_expr_int && !args[i]->null_value)
return args[i+1];
break;
case REAL_RESULT:
if (args[i]->val_real() == first_expr_real && !args[i]->null_value)
return args[i+1];
break;
case DECIMAL_RESULT:
{
my_decimal value;
if (my_decimal_cmp(args[i]->val_decimal(&value), first_expr_dec) == 0)
return args[i+1];
break;
}
case ROW_RESULT:
default:
// This case should never be chosen
DBUG_ASSERT(0);
break;
}
}
// No, WHEN clauses all missed, return ELSE expression
return else_expr_num != -1 ? args[else_expr_num] : 0;
}
String *Item_func_case::val_str(String *str)
{
DBUG_ASSERT(fixed == 1);
String *res;
Item *item=find_item(str);
if (!item)
{
null_value=1;
return 0;
}
null_value= 0;
if (!(res=item->val_str(str)))
null_value= 1;
return res;
}
longlong Item_func_case::val_int()
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff,sizeof(buff),default_charset());
Item *item=find_item(&dummy_str);
longlong res;
if (!item)
{
null_value=1;
return 0;
}
res=item->val_int();
null_value=item->null_value;
return res;
}
double Item_func_case::val_real()
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff,sizeof(buff),default_charset());
Item *item=find_item(&dummy_str);
double res;
if (!item)
{
null_value=1;
return 0;
}
res= item->val_real();
null_value=item->null_value;
return res;
}
my_decimal *Item_func_case::val_decimal(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String dummy_str(buff, sizeof(buff), default_charset());
Item *item= find_item(&dummy_str);
my_decimal *res;
if (!item)
{
null_value=1;
return 0;
}
res= item->val_decimal(decimal_value);
null_value= item->null_value;
return res;
}
bool Item_func_case::fix_fields(THD *thd, Item **ref)
{
/*
buff should match stack usage from
Item_func_case::val_int() -> Item_func_case::find_item()
*/
char buff[MAX_FIELD_WIDTH*2+sizeof(String)*2+sizeof(String*)*2+sizeof(double)*2+sizeof(longlong)*2];
bool res= Item_func::fix_fields(thd, ref);
/*
Call check_stack_overrun after fix_fields to be sure that stack variable
is not optimized away
*/
if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
return TRUE; // Fatal error flag is set!
return res;
}
void Item_func_case::fix_length_and_dec()
{
Item **agg;
uint nagg;
THD *thd= current_thd;
if (!(agg= (Item**) sql_alloc(sizeof(Item*)*(ncases+1))))
return;
/*
Aggregate all THEN and ELSE expression types
and collations when string result
*/
for (nagg= 0 ; nagg < ncases/2 ; nagg++)
agg[nagg]= args[nagg*2+1];
if (else_expr_num != -1)
agg[nagg++]= args[else_expr_num];
agg_result_type(&cached_result_type, agg, nagg);
if ((cached_result_type == STRING_RESULT) &&
agg_arg_charsets(collation, agg, nagg, MY_COLL_ALLOW_CONV, 1))
return;
/*
Aggregate first expression and all THEN expression types
and collations when string comparison
*/
if (first_expr_num != -1)
{
agg[0]= args[first_expr_num];
for (nagg= 0; nagg < ncases/2 ; nagg++)
agg[nagg+1]= args[nagg*2];
nagg++;
agg_cmp_type(thd, &cmp_type, agg, nagg);
if ((cmp_type == STRING_RESULT) &&
agg_arg_charsets(cmp_collation, agg, nagg, MY_COLL_CMP_CONV, 1))
return;
}
if (else_expr_num == -1 || args[else_expr_num]->maybe_null)
maybe_null=1;
max_length=0;
decimals=0;
for (uint i=0 ; i < ncases ; i+=2)
{
set_if_bigger(max_length,args[i+1]->max_length);
set_if_bigger(decimals,args[i+1]->decimals);
}
if (else_expr_num != -1)
{
set_if_bigger(max_length,args[else_expr_num]->max_length);
set_if_bigger(decimals,args[else_expr_num]->decimals);
}
}
uint Item_func_case::decimal_precision() const
{
int max_int_part=0;
for (uint i=0 ; i < ncases ; i+=2)
set_if_bigger(max_int_part, args[i+1]->decimal_int_part());
if (else_expr_num != -1)
set_if_bigger(max_int_part, args[else_expr_num]->decimal_int_part());
return min(max_int_part + decimals, DECIMAL_MAX_PRECISION);
}
/* TODO: Fix this so that it prints the whole CASE expression */
void Item_func_case::print(String *str)
{
str->append(STRING_WITH_LEN("(case "));
if (first_expr_num != -1)
{
args[first_expr_num]->print(str);
str->append(' ');
}
for (uint i=0 ; i < ncases ; i+=2)
{
str->append(STRING_WITH_LEN("when "));
args[i]->print(str);
str->append(STRING_WITH_LEN(" then "));
args[i+1]->print(str);
str->append(' ');
}
if (else_expr_num != -1)
{
str->append(STRING_WITH_LEN("else "));
args[else_expr_num]->print(str);
str->append(' ');
}
str->append(STRING_WITH_LEN("end)"));
}
/*
Coalesce - return first not NULL argument.
*/
String *Item_func_coalesce::str_op(String *str)
{
DBUG_ASSERT(fixed == 1);
null_value=0;
for (uint i=0 ; i < arg_count ; i++)
{
String *res;
if ((res=args[i]->val_str(str)))
return res;
}
null_value=1;
return 0;
}
longlong Item_func_coalesce::int_op()
{
DBUG_ASSERT(fixed == 1);
null_value=0;
for (uint i=0 ; i < arg_count ; i++)
{
longlong res=args[i]->val_int();
if (!args[i]->null_value)
return res;
}
null_value=1;
return 0;
}
double Item_func_coalesce::real_op()
{
DBUG_ASSERT(fixed == 1);
null_value=0;
for (uint i=0 ; i < arg_count ; i++)
{
double res= args[i]->val_real();
if (!args[i]->null_value)
return res;
}
null_value=1;
return 0;
}
my_decimal *Item_func_coalesce::decimal_op(my_decimal *decimal_value)
{
DBUG_ASSERT(fixed == 1);
null_value= 0;
for (uint i= 0; i < arg_count; i++)
{
my_decimal *res= args[i]->val_decimal(decimal_value);
if (!args[i]->null_value)
return res;
}
null_value=1;
return 0;
}
void Item_func_coalesce::fix_length_and_dec()
{
agg_result_type(&hybrid_type, args, arg_count);
switch (hybrid_type) {
case STRING_RESULT:
count_only_length();
decimals= NOT_FIXED_DEC;
agg_arg_charsets(collation, args, arg_count, MY_COLL_ALLOW_CONV, 1);
break;
case DECIMAL_RESULT:
count_decimal_length();
break;
case REAL_RESULT:
count_real_length();
break;
case INT_RESULT:
count_only_length();
decimals= 0;
break;
case ROW_RESULT:
default:
DBUG_ASSERT(0);
}
}
/****************************************************************************
Classes and function for the IN operator
****************************************************************************/
static int cmp_longlong(void *cmp_arg, longlong *a,longlong *b)
{
return *a < *b ? -1 : *a == *b ? 0 : 1;
}
static int cmp_double(void *cmp_arg, double *a,double *b)
{
return *a < *b ? -1 : *a == *b ? 0 : 1;
}
static int cmp_row(void *cmp_arg, cmp_item_row *a, cmp_item_row *b)
{
return a->compare(b);
}
static int cmp_decimal(void *cmp_arg, my_decimal *a, my_decimal *b)
{
/*
We need call of fixing buffer pointer, because fast sort just copy
decimal buffers in memory and pointers left pointing on old buffer place
*/
a->fix_buffer_pointer();
b->fix_buffer_pointer();
return my_decimal_cmp(a, b);
}
int in_vector::find(Item *item)
{
byte *result=get_value(item);
if (!result || !used_count)
return 0; // Null value
uint start,end;
start=0; end=used_count-1;
while (start != end)
{
uint mid=(start+end+1)/2;
int res;
if ((res=(*compare)(collation, base+mid*size, result)) == 0)
return 1;
if (res < 0)
start=mid;
else
end=mid-1;
}
return (int) ((*compare)(collation, base+start*size, result) == 0);
}
in_string::in_string(uint elements,qsort2_cmp cmp_func, CHARSET_INFO *cs)
:in_vector(elements, sizeof(String), cmp_func, cs),
tmp(buff, sizeof(buff), &my_charset_bin)
{}
in_string::~in_string()
{
if (base)
{
// base was allocated with help of sql_alloc => following is OK
for (uint i=0 ; i < count ; i++)
((String*) base)[i].free();
}
}
void in_string::set(uint pos,Item *item)
{
String *str=((String*) base)+pos;
String *res=item->val_str(str);
if (res && res != str)
{
if (res->uses_buffer_owned_by(str))
res->copy();
*str= *res;
}
if (!str->charset())
{
CHARSET_INFO *cs;
if (!(cs= item->collation.collation))
cs= &my_charset_bin; // Should never happen for STR items
str->set_charset(cs);
}
}
byte *in_string::get_value(Item *item)
{
return (byte*) item->val_str(&tmp);
}
in_row::in_row(uint elements, Item * item)
{
base= (char*) new cmp_item_row[count= elements];
size= sizeof(cmp_item_row);
compare= (qsort2_cmp) cmp_row;
tmp.store_value(item);
/*
We need to reset these as otherwise we will call sort() with
uninitialized (even if not used) elements
*/
used_count= elements;
collation= 0;
}
in_row::~in_row()
{
if (base)
delete [] (cmp_item_row*) base;
}
byte *in_row::get_value(Item *item)
{
tmp.store_value(item);
if (item->is_null())
return 0;
return (byte *)&tmp;
}
void in_row::set(uint pos, Item *item)
{
DBUG_ENTER("in_row::set");
DBUG_PRINT("enter", ("pos %u item 0x%lx", pos, (ulong) item));
((cmp_item_row*) base)[pos].store_value_by_template(&tmp, item);
DBUG_VOID_RETURN;
}
in_longlong::in_longlong(uint elements)
:in_vector(elements,sizeof(longlong),(qsort2_cmp) cmp_longlong, 0)
{}
void in_longlong::set(uint pos,Item *item)
{
((longlong*) base)[pos]=item->val_int();
}
byte *in_longlong::get_value(Item *item)
{
tmp= item->val_int();
if (item->null_value)
return 0;
return (byte*) &tmp;
}
in_double::in_double(uint elements)
:in_vector(elements,sizeof(double),(qsort2_cmp) cmp_double, 0)
{}
void in_double::set(uint pos,Item *item)
{
((double*) base)[pos]= item->val_real();
}
byte *in_double::get_value(Item *item)
{
tmp= item->val_real();
if (item->null_value)
return 0; /* purecov: inspected */
return (byte*) &tmp;
}
in_decimal::in_decimal(uint elements)
:in_vector(elements, sizeof(my_decimal),(qsort2_cmp) cmp_decimal, 0)
{}
void in_decimal::set(uint pos, Item *item)
{
/* as far as 'item' is constant, we can store reference on my_decimal */
my_decimal *dec= ((my_decimal *)base) + pos;
dec->len= DECIMAL_BUFF_LENGTH;
dec->fix_buffer_pointer();
my_decimal *res= item->val_decimal(dec);
if (res != dec)
my_decimal2decimal(res, dec);
}
byte *in_decimal::get_value(Item *item)
{
my_decimal *result= item->val_decimal(&val);
if (item->null_value)
return 0;
return (byte *)result;
}
cmp_item* cmp_item::get_comparator(Item_result type,
CHARSET_INFO *cs)
{
switch (type) {
case STRING_RESULT:
return new cmp_item_sort_string(cs);
case INT_RESULT:
return new cmp_item_int;
case REAL_RESULT:
return new cmp_item_real;
case ROW_RESULT:
return new cmp_item_row;
case DECIMAL_RESULT:
return new cmp_item_decimal;
default:
DBUG_ASSERT(0);
break;
}
return 0; // to satisfy compiler :)
}
cmp_item* cmp_item_sort_string::make_same()
{
return new cmp_item_sort_string_in_static(cmp_charset);
}
cmp_item* cmp_item_int::make_same()
{
return new cmp_item_int();
}
cmp_item* cmp_item_real::make_same()
{
return new cmp_item_real();
}
cmp_item* cmp_item_row::make_same()
{
return new cmp_item_row();
}
cmp_item_row::~cmp_item_row()
{
DBUG_ENTER("~cmp_item_row");
DBUG_PRINT("enter",("this: 0x%lx", (long) this));
if (comparators)
{
for (uint i= 0; i < n; i++)
{
if (comparators[i])
delete comparators[i];
}
}
DBUG_VOID_RETURN;
}
void cmp_item_row::store_value(Item *item)
{
DBUG_ENTER("cmp_item_row::store_value");
n= item->cols();
if (!comparators)
comparators= (cmp_item **) current_thd->calloc(sizeof(cmp_item *)*n);
if (comparators)
{
item->bring_value();
item->null_value= 0;
for (uint i=0; i < n; i++)
{
if (!comparators[i])
if (!(comparators[i]=
cmp_item::get_comparator(item->el(i)->result_type(),
item->el(i)->collation.collation)))
break; // new failed
comparators[i]->store_value(item->el(i));
item->null_value|= item->el(i)->null_value;
}
}
DBUG_VOID_RETURN;
}
void cmp_item_row::store_value_by_template(cmp_item *t, Item *item)
{
cmp_item_row *tmpl= (cmp_item_row*) t;
if (tmpl->n != item->cols())
{
my_error(ER_OPERAND_COLUMNS, MYF(0), tmpl->n);
return;
}
n= tmpl->n;
if ((comparators= (cmp_item **) sql_alloc(sizeof(cmp_item *)*n)))
{
item->bring_value();
item->null_value= 0;
for (uint i=0; i < n; i++)
{
if (!(comparators[i]= tmpl->comparators[i]->make_same()))
break; // new failed
comparators[i]->store_value_by_template(tmpl->comparators[i],
item->el(i));
item->null_value|= item->el(i)->null_value;
}
}
}
int cmp_item_row::cmp(Item *arg)
{
arg->null_value= 0;
if (arg->cols() != n)
{
my_error(ER_OPERAND_COLUMNS, MYF(0), n);
return 1;
}
bool was_null= 0;
arg->bring_value();
for (uint i=0; i < n; i++)
{
if (comparators[i]->cmp(arg->el(i)))
{
if (!arg->el(i)->null_value)
return 1;
was_null= 1;
}
}
return (arg->null_value= was_null);
}
int cmp_item_row::compare(cmp_item *c)
{
cmp_item_row *cmp= (cmp_item_row *) c;
for (uint i=0; i < n; i++)
{
int res;
if ((res= comparators[i]->compare(cmp->comparators[i])))
return res;
}
return 0;
}
void cmp_item_decimal::store_value(Item *item)
{
my_decimal *val= item->val_decimal(&value);
/* val may be zero if item is nnull */
if (val && val != &value)
my_decimal2decimal(val, &value);
}
int cmp_item_decimal::cmp(Item *arg)
{
my_decimal tmp_buf, *tmp= arg->val_decimal(&tmp_buf);
if (arg->null_value)
return 1;
return my_decimal_cmp(&value, tmp);
}
int cmp_item_decimal::compare(cmp_item *arg)
{
cmp_item_decimal *cmp= (cmp_item_decimal*) arg;
return my_decimal_cmp(&value, &cmp->value);
}
cmp_item* cmp_item_decimal::make_same()
{
return new cmp_item_decimal();
}
bool Item_func_in::nulls_in_row()
{
Item **arg,**arg_end;
for (arg= args+1, arg_end= args+arg_count; arg != arg_end ; arg++)
{
if ((*arg)->null_inside())
return 1;
}
return 0;
}
/*
Perform context analysis of an IN item tree
SYNOPSIS:
fix_fields()
thd reference to the global context of the query thread
tables list of all open tables involved in the query
ref pointer to Item* variable where pointer to resulting "fixed"
item is to be assigned
DESCRIPTION
This function performs context analysis (name resolution) and calculates
various attributes of the item tree with Item_func_in as its root.
The function saves in ref the pointer to the item or to a newly created
item that is considered as a replacement for the original one.
NOTES
Let T0(e)/T1(e) be the value of not_null_tables(e) when e is used on
a predicate/function level. Then it's easy to show that:
T0(e IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
T1(e IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
T0(e NOT IN(e1,...,en)) = union(T1(e),union(T1(ei)))
T1(e NOT IN(e1,...,en)) = union(T1(e),intersection(T1(ei)))
RETURN
0 ok
1 got error
*/
bool
Item_func_in::fix_fields(THD *thd, Item **ref)
{
Item **arg, **arg_end;
if (Item_func_opt_neg::fix_fields(thd, ref))
return 1;
/* not_null_tables_cache == union(T1(e),union(T1(ei))) */
if (pred_level && negated)
return 0;
/* not_null_tables_cache = union(T1(e),intersection(T1(ei))) */
not_null_tables_cache= ~(table_map) 0;
for (arg= args + 1, arg_end= args + arg_count; arg != arg_end; arg++)
not_null_tables_cache&= (*arg)->not_null_tables();
not_null_tables_cache|= (*args)->not_null_tables();
return 0;
}
static int srtcmp_in(CHARSET_INFO *cs, const String *x,const String *y)
{
return cs->coll->strnncollsp(cs,
(uchar *) x->ptr(),x->length(),
(uchar *) y->ptr(),y->length(), 0);
}
void Item_func_in::fix_length_and_dec()
{
Item **arg, **arg_end;
uint const_itm= 1;
THD *thd= current_thd;
agg_cmp_type(thd, &cmp_type, args, arg_count);
if (cmp_type == STRING_RESULT &&
agg_arg_charsets(cmp_collation, args, arg_count, MY_COLL_CMP_CONV, 1))
return;
for (arg=args+1, arg_end=args+arg_count; arg != arg_end ; arg++)
{
if (!arg[0]->const_item())
{
const_itm= 0;
break;
}
}
/*
Row item with NULLs inside can return NULL or FALSE =>
they can't be processed as static
*/
if (const_itm && !nulls_in_row())
{
switch (cmp_type) {
case STRING_RESULT:
array=new in_string(arg_count-1,(qsort2_cmp) srtcmp_in,
cmp_collation.collation);
break;
case INT_RESULT:
array= new in_longlong(arg_count-1);
break;
case REAL_RESULT:
array= new in_double(arg_count-1);
break;
case ROW_RESULT:
array= new in_row(arg_count-1, args[0]);
break;
case DECIMAL_RESULT:
array= new in_decimal(arg_count - 1);
break;
default:
DBUG_ASSERT(0);
return;
}
if (array && !(thd->is_fatal_error)) // If not EOM
{
uint j=0;
for (uint i=1 ; i < arg_count ; i++)
{
array->set(j,args[i]);
if (!args[i]->null_value) // Skip NULL values
j++;
else
have_null= 1;
}
if ((array->used_count=j))
array->sort();
}
}
else
{
in_item= cmp_item::get_comparator(cmp_type, cmp_collation.collation);
if (cmp_type == STRING_RESULT)
in_item->cmp_charset= cmp_collation.collation;
}
max_length= 1;
}
void Item_func_in::print(String *str)
{
str->append('(');
args[0]->print(str);
if (negated)
str->append(STRING_WITH_LEN(" not"));
str->append(STRING_WITH_LEN(" in ("));
print_args(str, 1);
str->append(STRING_WITH_LEN("))"));
}
longlong Item_func_in::val_int()
{
DBUG_ASSERT(fixed == 1);
if (array)
{
int tmp=array->find(args[0]);
null_value=args[0]->null_value || (!tmp && have_null);
return (longlong) (!null_value && tmp != negated);
}
in_item->store_value(args[0]);
if ((null_value=args[0]->null_value))
return 0;
have_null= 0;
for (uint i=1 ; i < arg_count ; i++)
{
if (!in_item->cmp(args[i]) && !args[i]->null_value)
return (longlong) (!negated);
have_null|= args[i]->null_value;
}
null_value= have_null;
return (longlong) (!null_value && negated);
}
longlong Item_func_bit_or::val_int()
{
DBUG_ASSERT(fixed == 1);
ulonglong arg1= (ulonglong) args[0]->val_int();
if (args[0]->null_value)
{
null_value=1; /* purecov: inspected */
return 0; /* purecov: inspected */
}
ulonglong arg2= (ulonglong) args[1]->val_int();
if (args[1]->null_value)
{
null_value=1;
return 0;
}
null_value=0;
return (longlong) (arg1 | arg2);
}
longlong Item_func_bit_and::val_int()
{
DBUG_ASSERT(fixed == 1);
ulonglong arg1= (ulonglong) args[0]->val_int();
if (args[0]->null_value)
{
null_value=1; /* purecov: inspected */
return 0; /* purecov: inspected */
}
ulonglong arg2= (ulonglong) args[1]->val_int();
if (args[1]->null_value)
{
null_value=1; /* purecov: inspected */
return 0; /* purecov: inspected */
}
null_value=0;
return (longlong) (arg1 & arg2);
}
Item_cond::Item_cond(THD *thd, Item_cond *item)
:Item_bool_func(thd, item),
abort_on_null(item->abort_on_null),
and_tables_cache(item->and_tables_cache)
{
/*
item->list will be copied by copy_andor_arguments() call
*/
}
void Item_cond::copy_andor_arguments(THD *thd, Item_cond *item)
{
List_iterator_fast<Item> li(item->list);
while (Item *it= li++)
list.push_back(it->copy_andor_structure(thd));
}
bool
Item_cond::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
List_iterator<Item> li(list);
Item *item;
#ifndef EMBEDDED_LIBRARY
char buff[sizeof(char*)]; // Max local vars in function
#endif
not_null_tables_cache= used_tables_cache= 0;
const_item_cache= 1;
/*
and_table_cache is the value that Item_cond_or() returns for
not_null_tables()
*/
and_tables_cache= ~(table_map) 0;
if (check_stack_overrun(thd, STACK_MIN_SIZE, buff))
return TRUE; // Fatal error flag is set!
/*
The following optimization reduces the depth of an AND-OR tree.
E.g. a WHERE clause like
F1 AND (F2 AND (F2 AND F4))
is parsed into a tree with the same nested structure as defined
by braces. This optimization will transform such tree into
AND (F1, F2, F3, F4).
Trees of OR items are flattened as well:
((F1 OR F2) OR (F3 OR F4)) => OR (F1, F2, F3, F4)
Items for removed AND/OR levels will dangle until the death of the
entire statement.
The optimization is currently prepared statements and stored procedures
friendly as it doesn't allocate any memory and its effects are durable
(i.e. do not depend on PS/SP arguments).
*/
while ((item=li++))
{
table_map tmp_table_map;
while (item->type() == Item::COND_ITEM &&
((Item_cond*) item)->functype() == functype() &&
!((Item_cond*) item)->list.is_empty())
{ // Identical function
li.replace(((Item_cond*) item)->list);
((Item_cond*) item)->list.empty();
item= *li.ref(); // new current item
}
if (abort_on_null)
item->top_level_item();
// item can be substituted in fix_fields
if ((!item->fixed &&
item->fix_fields(thd, li.ref())) ||
(item= *li.ref())->check_cols(1))
return TRUE; /* purecov: inspected */
used_tables_cache|= item->used_tables();
if (item->const_item())
and_tables_cache= (table_map) 0;
else
{
tmp_table_map= item->not_null_tables();
not_null_tables_cache|= tmp_table_map;
and_tables_cache&= tmp_table_map;
const_item_cache= FALSE;
}
with_sum_func= with_sum_func || item->with_sum_func;
with_subselect|= item->with_subselect;
if (item->maybe_null)
maybe_null=1;
}
thd->lex->current_select->cond_count+= list.elements;
fix_length_and_dec();
fixed= 1;
return FALSE;
}
bool Item_cond::walk(Item_processor processor, byte *arg)
{
List_iterator_fast<Item> li(list);
Item *item;
while ((item= li++))
if (item->walk(processor, arg))
return 1;
return Item_func::walk(processor, arg);
}
/*
Transform an Item_cond object with a transformer callback function
SYNOPSIS
transform()
transformer the transformer callback function to be applied to the nodes
of the tree of the object
arg parameter to be passed to the transformer
DESCRIPTION
The function recursively applies the transform method to each
member item of the condition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transformer is applied to the root node
of the Item_cond object.
RETURN VALUES
Item returned as the result of transformation of the root node
*/
Item *Item_cond::transform(Item_transformer transformer, byte *arg)
{
DBUG_ASSERT(!current_thd->is_stmt_prepare());
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
/*
THD::change_item_tree() should be called only if the tree was
really transformed, i.e. when a new item has been created.
Otherwise we'll be allocating a lot of unnecessary memory for
change records at each execution.
*/
if (new_item != item)
current_thd->change_item_tree(li.ref(), new_item);
}
return Item_func::transform(transformer, arg);
}
/*
Compile Item_cond object with a processor and a transformer callback functions
SYNOPSIS
compile()
analyzer the analyzer callback function to be applied to the nodes
of the tree of the object
arg_p in/out parameter to be passed to the analyzer
transformer the transformer callback function to be applied to the nodes
of the tree of the object
arg_t parameter to be passed to the transformer
DESCRIPTION
First the function applies the analyzer to the root node of
the Item_func object. Then if the analyzer succeeeds (returns TRUE)
the function recursively applies the compile method to member
item of the condition list.
If the call of the method for a member item returns a new item
the old item is substituted for a new one.
After this the transformer is applied to the root node
of the Item_cond object.
RETURN VALUES
Item returned as the result of transformation of the root node
*/
Item *Item_cond::compile(Item_analyzer analyzer, byte **arg_p,
Item_transformer transformer, byte *arg_t)
{
if (!(this->*analyzer)(arg_p))
return 0;
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
{
/*
The same parameter value of arg_p must be passed
to analyze any argument of the condition formula.
*/
byte *arg_v= *arg_p;
Item *new_item= item->compile(analyzer, &arg_v, transformer, arg_t);
if (new_item && new_item != item)
li.replace(new_item);
}
return Item_func::transform(transformer, arg_t);
}
void Item_cond::traverse_cond(Cond_traverser traverser,
void *arg, traverse_order order)
{
List_iterator<Item> li(list);
Item *item;
switch(order) {
case(PREFIX):
(*traverser)(this, arg);
while ((item= li++))
{
item->traverse_cond(traverser, arg, order);
}
(*traverser)(NULL, arg);
break;
case(POSTFIX):
while ((item= li++))
{
item->traverse_cond(traverser, arg, order);
}
(*traverser)(this, arg);
}
}
/*
Move SUM items out from item tree and replace with reference
SYNOPSIS
split_sum_func()
thd Thread handler
ref_pointer_array Pointer to array of reference fields
fields All fields in select
NOTES
This function is run on all expression (SELECT list, WHERE, HAVING etc)
that have or refer (HAVING) to a SUM expression.
The split is done to get an unique item for each SUM function
so that we can easily find and calculate them.
(Calculation done by update_sum_func() and copy_sum_funcs() in
sql_select.cc)
*/
void Item_cond::split_sum_func(THD *thd, Item **ref_pointer_array,
List<Item> &fields)
{
List_iterator<Item> li(list);
Item *item;
while ((item= li++))
item->split_sum_func2(thd, ref_pointer_array, fields, li.ref(), TRUE);
}
table_map
Item_cond::used_tables() const
{ // This caches used_tables
return used_tables_cache;
}
void Item_cond::update_used_tables()
{
List_iterator_fast<Item> li(list);
Item *item;
used_tables_cache=0;
const_item_cache=1;
while ((item=li++))
{
item->update_used_tables();
used_tables_cache|= item->used_tables();
const_item_cache&= item->const_item();
}
}
void Item_cond::print(String *str)
{
str->append('(');
List_iterator_fast<Item> li(list);
Item *item;
if ((item=li++))
item->print(str);
while ((item=li++))
{
str->append(' ');
str->append(func_name());
str->append(' ');
item->print(str);
}
str->append(')');
}
void Item_cond::neg_arguments(THD *thd)
{
List_iterator<Item> li(list);
Item *item;
while ((item= li++)) /* Apply not transformation to the arguments */
{
Item *new_item= item->neg_transformer(thd);
if (!new_item)
{
if (!(new_item= new Item_func_not(item)))
return; // Fatal OEM error
}
VOID(li.replace(new_item));
}
}
/*
Evaluation of AND(expr, expr, expr ...)
NOTES:
abort_if_null is set for AND expressions for which we don't care if the
result is NULL or 0. This is set for:
- WHERE clause
- HAVING clause
- IF(expression)
RETURN VALUES
1 If all expressions are true
0 If all expressions are false or if we find a NULL expression and
'abort_on_null' is set.
NULL if all expression are either 1 or NULL
*/
longlong Item_cond_and::val_int()
{
DBUG_ASSERT(fixed == 1);
List_iterator_fast<Item> li(list);
Item *item;
null_value= 0;
while ((item=li++))
{
if (!item->val_bool())
{
if (abort_on_null || !(null_value= item->null_value))
return 0; // return FALSE
}
}
return null_value ? 0 : 1;
}
longlong Item_cond_or::val_int()
{
DBUG_ASSERT(fixed == 1);
List_iterator_fast<Item> li(list);
Item *item;
null_value=0;
while ((item=li++))
{
if (item->val_bool())
{
null_value=0;
return 1;
}
if (item->null_value)
null_value=1;
}
return 0;
}
/*
Create an AND expression from two expressions
SYNOPSIS
and_expressions()
a expression or NULL
b expression.
org_item Don't modify a if a == *org_item
If a == NULL, org_item is set to point at b,
to ensure that future calls will not modify b.
NOTES
This will not modify item pointed to by org_item or b
The idea is that one can call this in a loop and create and
'and' over all items without modifying any of the original items.
RETURN
NULL Error
Item
*/
Item *and_expressions(Item *a, Item *b, Item **org_item)
{
if (!a)
return (*org_item= (Item*) b);
if (a == *org_item)
{
Item_cond *res;
if ((res= new Item_cond_and(a, (Item*) b)))
{
res->used_tables_cache= a->used_tables() | b->used_tables();
res->not_null_tables_cache= a->not_null_tables() | b->not_null_tables();
}
return res;
}
if (((Item_cond_and*) a)->add((Item*) b))
return 0;
((Item_cond_and*) a)->used_tables_cache|= b->used_tables();
((Item_cond_and*) a)->not_null_tables_cache|= b->not_null_tables();
return a;
}
longlong Item_func_isnull::val_int()
{
DBUG_ASSERT(fixed == 1);
/*
Handle optimization if the argument can't be null
This has to be here because of the test in update_used_tables().
*/
if (!used_tables_cache && !with_subselect)
return cached_value;
return args[0]->is_null() ? 1: 0;
}
longlong Item_is_not_null_test::val_int()
{
DBUG_ASSERT(fixed == 1);
DBUG_ENTER("Item_is_not_null_test::val_int");
if (!used_tables_cache && !with_subselect)
{
owner->was_null|= (!cached_value);
DBUG_PRINT("info", ("cached :%ld", (long) cached_value));
DBUG_RETURN(cached_value);
}
if (args[0]->is_null())
{
DBUG_PRINT("info", ("null"))
owner->was_null|= 1;
DBUG_RETURN(0);
}
else
DBUG_RETURN(1);
}
/* Optimize case of not_null_column IS NULL */
void Item_is_not_null_test::update_used_tables()
{
if (!args[0]->maybe_null)
{
used_tables_cache= 0; /* is always true */
cached_value= (longlong) 1;
}
else
{
args[0]->update_used_tables();
if (!(used_tables_cache=args[0]->used_tables()) && !with_subselect)
{
/* Remember if the value is always NULL or never NULL */
cached_value= (longlong) !args[0]->is_null();
}
}
}
longlong Item_func_isnotnull::val_int()
{
DBUG_ASSERT(fixed == 1);
return args[0]->is_null() ? 0 : 1;
}
void Item_func_isnotnull::print(String *str)
{
str->append('(');
args[0]->print(str);
str->append(STRING_WITH_LEN(" is not null)"));
}
longlong Item_func_like::val_int()
{
DBUG_ASSERT(fixed == 1);
String* res = args[0]->val_str(&tmp_value1);
if (args[0]->null_value)
{
null_value=1;
return 0;
}
String* res2 = args[1]->val_str(&tmp_value2);
if (args[1]->null_value)
{
null_value=1;
return 0;
}
null_value=0;
if (canDoTurboBM)
return turboBM_matches(res->ptr(), res->length()) ? 1 : 0;
return my_wildcmp(cmp.cmp_collation.collation,
res->ptr(),res->ptr()+res->length(),
res2->ptr(),res2->ptr()+res2->length(),
escape,wild_one,wild_many) ? 0 : 1;
}
/* We can optimize a where if first character isn't a wildcard */
Item_func::optimize_type Item_func_like::select_optimize() const
{
if (args[1]->const_item())
{
String* res2= args[1]->val_str((String *)&tmp_value2);
if (!res2)
return OPTIMIZE_NONE;
if (*res2->ptr() != wild_many)
{
if (args[0]->result_type() != STRING_RESULT || *res2->ptr() != wild_one)
return OPTIMIZE_OP;
}
}
return OPTIMIZE_NONE;
}
bool Item_func_like::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if (Item_bool_func2::fix_fields(thd, ref) ||
escape_item->fix_fields(thd, &escape_item))
return TRUE;
if (!escape_item->const_during_execution())
{
my_error(ER_WRONG_ARGUMENTS,MYF(0),"ESCAPE");
return TRUE;
}
if (escape_item->const_item())
{
/* If we are on execution stage */
String *escape_str= escape_item->val_str(&tmp_value1);
if (escape_str)
{
if (escape_used_in_parsing && (
(((thd->variables.sql_mode & MODE_NO_BACKSLASH_ESCAPES) &&
escape_str->numchars() != 1) ||
escape_str->numchars() > 1)))
{
my_error(ER_WRONG_ARGUMENTS,MYF(0),"ESCAPE");
return TRUE;
}
if (use_mb(cmp.cmp_collation.collation))
{
CHARSET_INFO *cs= escape_str->charset();
my_wc_t wc;
int rc= cs->cset->mb_wc(cs, &wc,
(const uchar*) escape_str->ptr(),
(const uchar*) escape_str->ptr() +
escape_str->length());
escape= (int) (rc > 0 ? wc : '\\');
}
else
{
/*
In the case of 8bit character set, we pass native
code instead of Unicode code as "escape" argument.
Convert to "cs" if charset of escape differs.
*/
CHARSET_INFO *cs= cmp.cmp_collation.collation;
uint32 unused;
if (escape_str->needs_conversion(escape_str->length(),
escape_str->charset(), cs, &unused))
{
char ch;
uint errors;
uint32 cnvlen= copy_and_convert(&ch, 1, cs, escape_str->ptr(),
escape_str->length(),
escape_str->charset(), &errors);
escape= cnvlen ? ch : '\\';
}
else
escape= *(escape_str->ptr());
}
}
else
escape= '\\';
/*
We could also do boyer-more for non-const items, but as we would have to
recompute the tables for each row it's not worth it.
*/
if (args[1]->const_item() && !use_strnxfrm(collation.collation) &&
!(specialflag & SPECIAL_NO_NEW_FUNC))
{
String* res2 = args[1]->val_str(&tmp_value2);
if (!res2)
return FALSE; // Null argument
const size_t len = res2->length();
const char* first = res2->ptr();
const char* last = first + len - 1;
/*
len must be > 2 ('%pattern%')
heuristic: only do TurboBM for pattern_len > 2
*/
if (len > MIN_TURBOBM_PATTERN_LEN + 2 &&
*first == wild_many &&
*last == wild_many)
{
const char* tmp = first + 1;
for (; *tmp != wild_many && *tmp != wild_one && *tmp != escape; tmp++) ;
canDoTurboBM = (tmp == last) && !use_mb(args[0]->collation.collation);
}
if (canDoTurboBM)
{
pattern = first + 1;
pattern_len = (int) len - 2;
DBUG_PRINT("info", ("Initializing pattern: '%s'", first));
int *suff = (int*) thd->alloc((int) (sizeof(int)*
((pattern_len + 1)*2+
alphabet_size)));
bmGs = suff + pattern_len + 1;
bmBc = bmGs + pattern_len + 1;
turboBM_compute_good_suffix_shifts(suff);
turboBM_compute_bad_character_shifts();
DBUG_PRINT("info",("done"));
}
}
}
return FALSE;
}
void Item_func_like::cleanup()
{
canDoTurboBM= FALSE;
Item_bool_func2::cleanup();
}
#ifdef USE_REGEX
bool
Item_func_regex::fix_fields(THD *thd, Item **ref)
{
DBUG_ASSERT(fixed == 0);
if ((!args[0]->fixed &&
args[0]->fix_fields(thd, args)) || args[0]->check_cols(1) ||
(!args[1]->fixed &&
args[1]->fix_fields(thd, args + 1)) || args[1]->check_cols(1))
return TRUE; /* purecov: inspected */
with_sum_func=args[0]->with_sum_func || args[1]->with_sum_func;
max_length= 1;
decimals= 0;
if (agg_arg_charsets(cmp_collation, args, 2, MY_COLL_CMP_CONV, 1))
return TRUE;
used_tables_cache=args[0]->used_tables() | args[1]->used_tables();
not_null_tables_cache= (args[0]->not_null_tables() |
args[1]->not_null_tables());
const_item_cache=args[0]->const_item() && args[1]->const_item();
if (!regex_compiled && args[1]->const_item())
{
char buff[MAX_FIELD_WIDTH];
String tmp(buff,sizeof(buff),&my_charset_bin);
String *res=args[1]->val_str(&tmp);
if (args[1]->null_value)
{ // Will always return NULL
maybe_null=1;
return FALSE;
}
int error;
if ((error= my_regcomp(&preg,res->c_ptr(),
((cmp_collation.collation->state &
(MY_CS_BINSORT | MY_CS_CSSORT)) ?
REG_EXTENDED | REG_NOSUB :
REG_EXTENDED | REG_NOSUB | REG_ICASE),
cmp_collation.collation)))
{
(void) my_regerror(error,&preg,buff,sizeof(buff));
my_error(ER_REGEXP_ERROR, MYF(0), buff);
return TRUE;
}
regex_compiled=regex_is_const=1;
maybe_null=args[0]->maybe_null;
}
else
maybe_null=1;
fixed= 1;
return FALSE;
}
longlong Item_func_regex::val_int()
{
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String *res, tmp(buff,sizeof(buff),&my_charset_bin);
res=args[0]->val_str(&tmp);
if (args[0]->null_value)
{
null_value=1;
return 0;
}
if (!regex_is_const)
{
char buff2[MAX_FIELD_WIDTH];
String *res2, tmp2(buff2,sizeof(buff2),&my_charset_bin);
res2= args[1]->val_str(&tmp2);
if (args[1]->null_value)
{
null_value=1;
return 0;
}
if (!regex_compiled || stringcmp(res2,&prev_regexp))
{
prev_regexp.copy(*res2);
if (regex_compiled)
{
my_regfree(&preg);
regex_compiled=0;
}
if (my_regcomp(&preg,res2->c_ptr_safe(),
((cmp_collation.collation->state &
(MY_CS_BINSORT | MY_CS_CSSORT)) ?
REG_EXTENDED | REG_NOSUB :
REG_EXTENDED | REG_NOSUB | REG_ICASE),
cmp_collation.collation))
{
null_value=1;
return 0;
}
regex_compiled=1;
}
}
null_value=0;
return my_regexec(&preg,res->c_ptr_safe(),0,(my_regmatch_t*) 0,0) ? 0 : 1;
}
void Item_func_regex::cleanup()
{
DBUG_ENTER("Item_func_regex::cleanup");
Item_bool_func::cleanup();
if (regex_compiled)
{
my_regfree(&preg);
regex_compiled=0;
}
DBUG_VOID_RETURN;
}
#endif /* USE_REGEX */
#ifdef LIKE_CMP_TOUPPER
#define likeconv(cs,A) (uchar) (cs)->toupper(A)
#else
#define likeconv(cs,A) (uchar) (cs)->sort_order[(uchar) (A)]
#endif
/**********************************************************************
turboBM_compute_suffixes()
Precomputation dependent only on pattern_len.
**********************************************************************/
void Item_func_like::turboBM_compute_suffixes(int *suff)
{
const int plm1 = pattern_len - 1;
int f = 0;
int g = plm1;
int *const splm1 = suff + plm1;
CHARSET_INFO *cs= cmp.cmp_collation.collation;
*splm1 = pattern_len;
if (!cs->sort_order)
{
int i;
for (i = pattern_len - 2; i >= 0; i--)
{
int tmp = *(splm1 + i - f);
if (g < i && tmp < i - g)
suff[i] = tmp;
else
{
if (i < g)
g = i; // g = min(i, g)
f = i;
while (g >= 0 && pattern[g] == pattern[g + plm1 - f])
g--;
suff[i] = f - g;
}
}
}
else
{
int i;
for (i = pattern_len - 2; 0 <= i; --i)
{
int tmp = *(splm1 + i - f);
if (g < i && tmp < i - g)
suff[i] = tmp;
else
{
if (i < g)
g = i; // g = min(i, g)
f = i;
while (g >= 0 &&
likeconv(cs, pattern[g]) == likeconv(cs, pattern[g + plm1 - f]))
g--;
suff[i] = f - g;
}
}
}
}
/**********************************************************************
turboBM_compute_good_suffix_shifts()
Precomputation dependent only on pattern_len.
**********************************************************************/
void Item_func_like::turboBM_compute_good_suffix_shifts(int *suff)
{
turboBM_compute_suffixes(suff);
int *end = bmGs + pattern_len;
int *k;
for (k = bmGs; k < end; k++)
*k = pattern_len;
int tmp;
int i;
int j = 0;
const int plm1 = pattern_len - 1;
for (i = plm1; i > -1; i--)
{
if (suff[i] == i + 1)
{
for (tmp = plm1 - i; j < tmp; j++)
{
int *tmp2 = bmGs + j;
if (*tmp2 == pattern_len)
*tmp2 = tmp;
}
}
}
int *tmp2;
for (tmp = plm1 - i; j < tmp; j++)
{
tmp2 = bmGs + j;
if (*tmp2 == pattern_len)
*tmp2 = tmp;
}
tmp2 = bmGs + plm1;
for (i = 0; i <= pattern_len - 2; i++)
*(tmp2 - suff[i]) = plm1 - i;
}
/**********************************************************************
turboBM_compute_bad_character_shifts()
Precomputation dependent on pattern_len.
**********************************************************************/
void Item_func_like::turboBM_compute_bad_character_shifts()
{
int *i;
int *end = bmBc + alphabet_size;
int j;
const int plm1 = pattern_len - 1;
CHARSET_INFO *cs= cmp.cmp_collation.collation;
for (i = bmBc; i < end; i++)
*i = pattern_len;
if (!cs->sort_order)
{
for (j = 0; j < plm1; j++)
bmBc[(uint) (uchar) pattern[j]] = plm1 - j;
}
else
{
for (j = 0; j < plm1; j++)
bmBc[(uint) likeconv(cs,pattern[j])] = plm1 - j;
}
}
/**********************************************************************
turboBM_matches()
Search for pattern in text, returns true/false for match/no match
**********************************************************************/
bool Item_func_like::turboBM_matches(const char* text, int text_len) const
{
register int bcShift;
register int turboShift;
int shift = pattern_len;
int j = 0;
int u = 0;
CHARSET_INFO *cs= cmp.cmp_collation.collation;
const int plm1= pattern_len - 1;
const int tlmpl= text_len - pattern_len;
/* Searching */
if (!cs->sort_order)
{
while (j <= tlmpl)
{
register int i= plm1;
while (i >= 0 && pattern[i] == text[i + j])
{
i--;
if (i == plm1 - shift)
i-= u;
}
if (i < 0)
return 1;
register const int v = plm1 - i;
turboShift = u - v;
bcShift = bmBc[(uint) (uchar) text[i + j]] - plm1 + i;
shift = max(turboShift, bcShift);
shift = max(shift, bmGs[i]);
if (shift == bmGs[i])
u = min(pattern_len - shift, v);
else
{
if (turboShift < bcShift)
shift = max(shift, u + 1);
u = 0;
}
j+= shift;
}
return 0;
}
else
{
while (j <= tlmpl)
{
register int i = plm1;
while (i >= 0 && likeconv(cs,pattern[i]) == likeconv(cs,text[i + j]))
{
i--;
if (i == plm1 - shift)
i-= u;
}
if (i < 0)
return 1;
register const int v = plm1 - i;
turboShift = u - v;
bcShift = bmBc[(uint) likeconv(cs, text[i + j])] - plm1 + i;
shift = max(turboShift, bcShift);
shift = max(shift, bmGs[i]);
if (shift == bmGs[i])
u = min(pattern_len - shift, v);
else
{
if (turboShift < bcShift)
shift = max(shift, u + 1);
u = 0;
}
j+= shift;
}
return 0;
}
}
/*
Make a logical XOR of the arguments.
SYNOPSIS
val_int()
DESCRIPTION
If either operator is NULL, return NULL.
NOTE
As we don't do any index optimization on XOR this is not going to be
very fast to use.
TODO (low priority)
Change this to be optimized as:
A XOR B -> (A) == 1 AND (B) <> 1) OR (A <> 1 AND (B) == 1)
To be able to do this, we would however first have to extend the MySQL
range optimizer to handle OR better.
*/
longlong Item_cond_xor::val_int()
{
DBUG_ASSERT(fixed == 1);
List_iterator<Item> li(list);
Item *item;
int result=0;
null_value=0;
while ((item=li++))
{
result^= (item->val_int() != 0);
if (item->null_value)
{
null_value=1;
return 0;
}
}
return (longlong) result;
}
/*
Apply NOT transformation to the item and return a new one.
SYNOPSIS
neg_transformer()
thd thread handler
DESCRIPTION
Transform the item using next rules:
a AND b AND ... -> NOT(a) OR NOT(b) OR ...
a OR b OR ... -> NOT(a) AND NOT(b) AND ...
NOT(a) -> a
a = b -> a != b
a != b -> a = b
a < b -> a >= b
a >= b -> a < b
a > b -> a <= b
a <= b -> a > b
IS NULL(a) -> IS NOT NULL(a)
IS NOT NULL(a) -> IS NULL(a)
RETURN
New item or
NULL if we cannot apply NOT transformation (see Item::neg_transformer()).
*/
Item *Item_func_not::neg_transformer(THD *thd) /* NOT(x) -> x */
{
return args[0];
}
Item *Item_bool_rowready_func2::neg_transformer(THD *thd)
{
Item *item= negated_item();
return item;
}
/* a IS NULL -> a IS NOT NULL */
Item *Item_func_isnull::neg_transformer(THD *thd)
{
Item *item= new Item_func_isnotnull(args[0]);
return item;
}
/* a IS NOT NULL -> a IS NULL */
Item *Item_func_isnotnull::neg_transformer(THD *thd)
{
Item *item= new Item_func_isnull(args[0]);
return item;
}
Item *Item_cond_and::neg_transformer(THD *thd) /* NOT(a AND b AND ...) -> */
/* NOT a OR NOT b OR ... */
{
neg_arguments(thd);
Item *item= new Item_cond_or(list);
return item;
}
Item *Item_cond_or::neg_transformer(THD *thd) /* NOT(a OR b OR ...) -> */
/* NOT a AND NOT b AND ... */
{
neg_arguments(thd);
Item *item= new Item_cond_and(list);
return item;
}
Item *Item_func_nop_all::neg_transformer(THD *thd)
{
/* "NOT (e $cmp$ ANY (SELECT ...)) -> e $rev_cmp$" ALL (SELECT ...) */
Item_func_not_all *new_item= new Item_func_not_all(args[0]);
Item_allany_subselect *allany= (Item_allany_subselect*)args[0];
allany->func= allany->func_creator(FALSE);
allany->all= !allany->all;
allany->upper_item= new_item;
return new_item;
}
Item *Item_func_not_all::neg_transformer(THD *thd)
{
/* "NOT (e $cmp$ ALL (SELECT ...)) -> e $rev_cmp$" ANY (SELECT ...) */
Item_func_nop_all *new_item= new Item_func_nop_all(args[0]);
Item_allany_subselect *allany= (Item_allany_subselect*)args[0];
allany->all= !allany->all;
allany->func= allany->func_creator(TRUE);
allany->upper_item= new_item;
return new_item;
}
Item *Item_func_eq::negated_item() /* a = b -> a != b */
{
return new Item_func_ne(args[0], args[1]);
}
Item *Item_func_ne::negated_item() /* a != b -> a = b */
{
return new Item_func_eq(args[0], args[1]);
}
Item *Item_func_lt::negated_item() /* a < b -> a >= b */
{
return new Item_func_ge(args[0], args[1]);
}
Item *Item_func_ge::negated_item() /* a >= b -> a < b */
{
return new Item_func_lt(args[0], args[1]);
}
Item *Item_func_gt::negated_item() /* a > b -> a <= b */
{
return new Item_func_le(args[0], args[1]);
}
Item *Item_func_le::negated_item() /* a <= b -> a > b */
{
return new Item_func_gt(args[0], args[1]);
}
// just fake method, should never be called
Item *Item_bool_rowready_func2::negated_item()
{
DBUG_ASSERT(0);
return 0;
}
Item_equal::Item_equal(Item_field *f1, Item_field *f2)
: Item_bool_func(), const_item(0), eval_item(0), cond_false(0)
{
const_item_cache= 0;
fields.push_back(f1);
fields.push_back(f2);
}
Item_equal::Item_equal(Item *c, Item_field *f)
: Item_bool_func(), eval_item(0), cond_false(0)
{
const_item_cache= 0;
fields.push_back(f);
const_item= c;
}
Item_equal::Item_equal(Item_equal *item_equal)
: Item_bool_func(), eval_item(0), cond_false(0)
{
const_item_cache= 0;
List_iterator_fast<Item_field> li(item_equal->fields);
Item_field *item;
while ((item= li++))
{
fields.push_back(item);
}
const_item= item_equal->const_item;
cond_false= item_equal->cond_false;
}
void Item_equal::add(Item *c)
{
if (cond_false)
return;
if (!const_item)
{
const_item= c;
return;
}
Item_func_eq *func= new Item_func_eq(c, const_item);
func->set_cmp_func();
func->quick_fix_field();
if ((cond_false= !func->val_int()))
const_item_cache= 1;
}
void Item_equal::add(Item_field *f)
{
fields.push_back(f);
}
uint Item_equal::members()
{
return fields.elements;
}
/*
Check whether a field is referred in the multiple equality
SYNOPSIS
contains()
field field whose occurrence is to be checked
DESCRIPTION
The function checks whether field is occurred in the Item_equal object
RETURN VALUES
1 if nultiple equality contains a reference to field
0 otherwise
*/
bool Item_equal::contains(Field *field)
{
List_iterator_fast<Item_field> it(fields);
Item_field *item;
while ((item= it++))
{
if (field->eq(item->field))
return 1;
}
return 0;
}
/*
Join members of another Item_equal object
SYNOPSIS
merge()
item multiple equality whose members are to be joined
DESCRIPTION
The function actually merges two multiple equalities.
After this operation the Item_equal object additionally contains
the field items of another item of the type Item_equal.
If the optional constant items are not equal the cond_false flag is
set to 1.
RETURN VALUES
none
*/
void Item_equal::merge(Item_equal *item)
{
fields.concat(&item->fields);
Item *c= item->const_item;
if (c)
{
/*
The flag cond_false will be set to 1 after this, if
the multiple equality already contains a constant and its
value is not equal to the value of c.
*/
add(c);
}
cond_false|= item->cond_false;
}
/*
Order field items in multiple equality according to a sorting criteria
SYNOPSIS
sort()
cmp function to compare field item
arg context extra parameter for the cmp function
DESCRIPTION
The function perform ordering of the field items in the Item_equal
object according to the criteria determined by the cmp callback parameter.
If cmp(item_field1,item_field2,arg)<0 than item_field1 must be
placed after item_fiel2.
IMPLEMENTATION
The function sorts field items by the exchange sort algorithm.
The list of field items is looked through and whenever two neighboring
members follow in a wrong order they are swapped. This is performed
again and again until we get all members in a right order.
RETURN VALUES
None
*/
void Item_equal::sort(Item_field_cmpfunc cmp, void *arg)
{
bool swap;
List_iterator<Item_field> it(fields);
do
{
Item_field *item1= it++;
Item_field **ref1= it.ref();
Item_field *item2;
swap= FALSE;
while ((item2= it++))
{
Item_field **ref2= it.ref();
if (cmp(item1, item2, arg) < 0)
{
Item_field *item= *ref1;
*ref1= *ref2;
*ref2= item;
swap= TRUE;
}
else
{
item1= item2;
ref1= ref2;
}
}
it.rewind();
} while (swap);
}
/*
Check appearance of new constant items in the multiple equality object
SYNOPSIS
update_const()
DESCRIPTION
The function checks appearance of new constant items among
the members of multiple equalities. Each new constant item is
compared with the designated constant item if there is any in the
multiple equality. If there is none the first new constant item
becomes designated.
RETURN VALUES
none
*/
void Item_equal::update_const()
{
List_iterator<Item_field> it(fields);
Item *item;
while ((item= it++))
{
if (item->const_item())
{
it.remove();
add(item);
}
}
}
bool Item_equal::fix_fields(THD *thd, Item **ref)
{
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache= used_tables_cache= 0;
const_item_cache= 0;
while ((item= li++))
{
table_map tmp_table_map;
used_tables_cache|= item->used_tables();
tmp_table_map= item->not_null_tables();
not_null_tables_cache|= tmp_table_map;
if (item->maybe_null)
maybe_null=1;
}
fix_length_and_dec();
fixed= 1;
return 0;
}
void Item_equal::update_used_tables()
{
List_iterator_fast<Item_field> li(fields);
Item *item;
not_null_tables_cache= used_tables_cache= 0;
if ((const_item_cache= cond_false))
return;
while ((item=li++))
{
item->update_used_tables();
used_tables_cache|= item->used_tables();
const_item_cache&= item->const_item();
}
}
longlong Item_equal::val_int()
{
Item_field *item_field;
if (cond_false)
return 0;
List_iterator_fast<Item_field> it(fields);
Item *item= const_item ? const_item : it++;
if ((null_value= item->null_value))
return 0;
eval_item->store_value(item);
while ((item_field= it++))
{
/* Skip fields of non-const tables. They haven't been read yet */
if (item_field->field->table->const_table)
{
if ((null_value= item_field->null_value) || eval_item->cmp(item_field))
return 0;
}
}
return 1;
}
void Item_equal::fix_length_and_dec()
{
Item *item= const_item ? const_item : get_first();
eval_item= cmp_item::get_comparator(item->result_type(),
item->collation.collation);
if (item->result_type() == STRING_RESULT)
eval_item->cmp_charset= cmp_collation.collation;
}
bool Item_equal::walk(Item_processor processor, byte *arg)
{
List_iterator_fast<Item_field> it(fields);
Item *item;
while ((item= it++))
if (item->walk(processor, arg))
return 1;
return Item_func::walk(processor, arg);
}
Item *Item_equal::transform(Item_transformer transformer, byte *arg)
{
DBUG_ASSERT(!current_thd->is_stmt_prepare());
List_iterator<Item_field> it(fields);
Item *item;
while ((item= it++))
{
Item *new_item= item->transform(transformer, arg);
if (!new_item)
return 0;
/*
THD::change_item_tree() should be called only if the tree was
really transformed, i.e. when a new item has been created.
Otherwise we'll be allocating a lot of unnecessary memory for
change records at each execution.
*/
if (new_item != item)
current_thd->change_item_tree((Item **) it.ref(), new_item);
}
return Item_func::transform(transformer, arg);
}
void Item_equal::print(String *str)
{
str->append(func_name());
str->append('(');
List_iterator_fast<Item_field> it(fields);
Item *item;
if (const_item)
const_item->print(str);
else
{
item= it++;
item->print(str);
}
while ((item= it++))
{
str->append(',');
str->append(' ');
item->print(str);
}
str->append(')');
}
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