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mariadb/sql/sp_rcontext.cc
Michael Widenius 6920457142 Merge with MariaDB 5.1
2011-11-24 18:48:58 +02:00

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/*
Copyright (c) 2003-2008 MySQL AB, 2009 Sun Microsystems, Inc.
Use is subject to license terms.
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "mysql_priv.h"
#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation
#endif
#if defined(WIN32) || defined(__WIN__)
#undef SAFEMALLOC /* Problems with threads */
#endif
#include "mysql.h"
#include "sp_head.h"
#include "sql_cursor.h"
#include "sp_rcontext.h"
#include "sp_pcontext.h"
sp_rcontext::sp_rcontext(sp_pcontext *root_parsing_ctx,
Field *return_value_fld,
sp_rcontext *prev_runtime_ctx)
:m_root_parsing_ctx(root_parsing_ctx),
m_var_table(0),
m_var_items(0),
m_return_value_fld(return_value_fld),
m_return_value_set(FALSE),
in_sub_stmt(FALSE),
m_hcount(0),
m_hsp(0),
m_ihsp(0),
m_hfound(-1),
m_ccount(0),
m_case_expr_holders(0),
m_prev_runtime_ctx(prev_runtime_ctx)
{
}
sp_rcontext::~sp_rcontext()
{
if (m_var_table)
free_blobs(m_var_table);
}
/*
Initialize sp_rcontext instance.
SYNOPSIS
thd Thread handle
RETURN
FALSE on success
TRUE on error
*/
bool sp_rcontext::init(THD *thd)
{
in_sub_stmt= thd->in_sub_stmt;
if (init_var_table(thd) || init_var_items())
return TRUE;
return
!(m_handler=
(sp_handler_t*)thd->alloc(m_root_parsing_ctx->max_handler_index() *
sizeof(sp_handler_t))) ||
!(m_hstack=
(uint*)thd->alloc(m_root_parsing_ctx->max_handler_index() *
sizeof(uint))) ||
!(m_in_handler=
(uint*)thd->alloc(m_root_parsing_ctx->max_handler_index() *
sizeof(uint))) ||
!(m_cstack=
(sp_cursor**)thd->alloc(m_root_parsing_ctx->max_cursor_index() *
sizeof(sp_cursor*))) ||
!(m_case_expr_holders=
(Item_cache**)thd->calloc(m_root_parsing_ctx->get_num_case_exprs() *
sizeof (Item_cache*)));
}
/*
Create and initialize a table to store SP-vars.
SYNOPSIS
thd Thread handler.
RETURN
FALSE on success
TRUE on error
*/
bool
sp_rcontext::init_var_table(THD *thd)
{
List<Create_field> field_def_lst;
if (!m_root_parsing_ctx->max_var_index())
return FALSE;
m_root_parsing_ctx->retrieve_field_definitions(&field_def_lst);
DBUG_ASSERT(field_def_lst.elements == m_root_parsing_ctx->max_var_index());
if (!(m_var_table= create_virtual_tmp_table(thd, field_def_lst)))
return TRUE;
m_var_table->copy_blobs= TRUE;
m_var_table->alias.set("", 0, table_alias_charset);
return FALSE;
}
/*
Create and initialize an Item-adapter (Item_field) for each SP-var field.
RETURN
FALSE on success
TRUE on error
*/
bool
sp_rcontext::init_var_items()
{
uint idx;
uint num_vars= m_root_parsing_ctx->max_var_index();
if (!(m_var_items= (Item**) sql_alloc(num_vars * sizeof (Item *))))
return TRUE;
for (idx = 0; idx < num_vars; ++idx)
{
if (!(m_var_items[idx]= new Item_field(m_var_table->field[idx])))
return TRUE;
}
return FALSE;
}
bool
sp_rcontext::set_return_value(THD *thd, Item **return_value_item)
{
DBUG_ASSERT(m_return_value_fld);
m_return_value_set = TRUE;
return sp_eval_expr(thd, m_return_value_fld, return_value_item);
}
#define IS_WARNING_CONDITION(S) ((S)[0] == '0' && (S)[1] == '1')
#define IS_NOT_FOUND_CONDITION(S) ((S)[0] == '0' && (S)[1] == '2')
#define IS_EXCEPTION_CONDITION(S) ((S)[0] != '0' || (S)[1] > '2')
/*
Find a handler for the given errno.
This is called from all error message functions (e.g. push_warning,
net_send_error, et al) when a sp_rcontext is in effect. If a handler
is found, no error is sent, and the the SP execution loop will instead
invoke the found handler.
This might be called several times before we get back to the execution
loop, so m_hfound can be >= 0 if a handler has already been found.
(In which case we don't search again - the first found handler will
be used.)
Handlers are pushed on the stack m_handler, with the latest/innermost
one on the top; we then search for matching handlers from the top and
down.
We search through all the handlers, looking for the most specific one
(sql_errno more specific than sqlstate more specific than the rest).
Note that mysql error code handlers is a MySQL extension, not part of
the standard.
SYNOPSIS
sql_errno The error code
level Warning level
RETURN
1 if a handler was found, m_hfound is set to its index (>= 0)
0 if not found, m_hfound is -1
*/
bool
sp_rcontext::find_handler(THD *thd, uint sql_errno,
MYSQL_ERROR::enum_warning_level level)
{
if (m_hfound >= 0)
return 1; // Already got one
const char *sqlstate= mysql_errno_to_sqlstate(sql_errno);
int i= m_hcount, found= -1;
/*
If this is a fatal sub-statement error, and this runtime
context corresponds to a sub-statement, no CONTINUE/EXIT
handlers from this context are applicable: try to locate one
in the outer scope.
*/
if (thd->is_fatal_sub_stmt_error && in_sub_stmt)
i= 0;
/* Search handlers from the latest (innermost) to the oldest (outermost) */
while (i--)
{
sp_cond_type_t *cond= m_handler[i].cond;
int j= m_ihsp;
/* Check active handlers, to avoid invoking one recursively */
while (j--)
if (m_in_handler[j] == m_handler[i].handler)
break;
if (j >= 0)
continue; // Already executing this handler
switch (cond->type)
{
case sp_cond_type_t::number:
if (sql_errno == cond->mysqlerr &&
(found < 0 || m_handler[found].cond->type > sp_cond_type_t::number))
found= i; // Always the most specific
break;
case sp_cond_type_t::state:
if (strcmp(sqlstate, cond->sqlstate) == 0 &&
(found < 0 || m_handler[found].cond->type > sp_cond_type_t::state))
found= i;
break;
case sp_cond_type_t::warning:
if ((IS_WARNING_CONDITION(sqlstate) ||
level == MYSQL_ERROR::WARN_LEVEL_WARN) &&
found < 0)
found= i;
break;
case sp_cond_type_t::notfound:
if (IS_NOT_FOUND_CONDITION(sqlstate) && found < 0)
found= i;
break;
case sp_cond_type_t::exception:
if (IS_EXCEPTION_CONDITION(sqlstate) &&
level == MYSQL_ERROR::WARN_LEVEL_ERROR &&
found < 0)
found= i;
break;
}
}
if (found < 0)
{
/*
Only "exception conditions" are propagated to handlers in calling
contexts. If no handler is found locally for a "completion condition"
(warning or "not found") we will simply resume execution.
*/
if (m_prev_runtime_ctx && IS_EXCEPTION_CONDITION(sqlstate) &&
level == MYSQL_ERROR::WARN_LEVEL_ERROR)
return m_prev_runtime_ctx->find_handler(thd, sql_errno, level);
return FALSE;
}
m_hfound= found;
return TRUE;
}
/*
Handle the error for a given errno.
The severity of the error is adjusted depending of the current sql_mode.
If an handler is present for the error (see find_handler()),
this function will return true.
If a handler is found and if the severity of the error indicate
that the current instruction executed should abort,
the flag thd->net.report_error is also set.
This will cause the execution of the current instruction in a
sp_instr* to fail, and give control to the handler code itself
in the sp_head::execute() loop.
SYNOPSIS
sql_errno The error code
level Warning level
thd The current thread
RETURN
TRUE if a handler was found.
FALSE if no handler was found.
*/
bool
sp_rcontext::handle_error(uint sql_errno,
MYSQL_ERROR::enum_warning_level level,
THD *thd)
{
MYSQL_ERROR::enum_warning_level elevated_level= level;
/* Depending on the sql_mode of execution,
warnings may be considered errors */
if ((level == MYSQL_ERROR::WARN_LEVEL_WARN) &&
thd->really_abort_on_warning())
{
elevated_level= MYSQL_ERROR::WARN_LEVEL_ERROR;
}
return find_handler(thd, sql_errno, elevated_level);
}
void
sp_rcontext::push_cursor(sp_lex_keeper *lex_keeper, sp_instr_cpush *i)
{
DBUG_ENTER("sp_rcontext::push_cursor");
DBUG_ASSERT(m_ccount < m_root_parsing_ctx->max_cursor_index());
m_cstack[m_ccount++]= new sp_cursor(lex_keeper, i);
DBUG_PRINT("info", ("m_ccount: %d", m_ccount));
DBUG_VOID_RETURN;
}
void
sp_rcontext::pop_cursors(uint count)
{
DBUG_ENTER("sp_rcontext::pop_cursors");
DBUG_ASSERT(m_ccount >= count);
while (count--)
{
delete m_cstack[--m_ccount];
}
DBUG_PRINT("info", ("m_ccount: %d", m_ccount));
DBUG_VOID_RETURN;
}
void
sp_rcontext::push_handler(struct sp_cond_type *cond, uint h, int type, uint f)
{
DBUG_ENTER("sp_rcontext::push_handler");
DBUG_ASSERT(m_hcount < m_root_parsing_ctx->max_handler_index());
m_handler[m_hcount].cond= cond;
m_handler[m_hcount].handler= h;
m_handler[m_hcount].type= type;
m_handler[m_hcount].foffset= f;
m_hcount+= 1;
DBUG_PRINT("info", ("m_hcount: %d", m_hcount));
DBUG_VOID_RETURN;
}
void
sp_rcontext::pop_handlers(uint count)
{
DBUG_ENTER("sp_rcontext::pop_handlers");
DBUG_ASSERT(m_hcount >= count);
m_hcount-= count;
DBUG_PRINT("info", ("m_hcount: %d", m_hcount));
DBUG_VOID_RETURN;
}
void
sp_rcontext::push_hstack(uint h)
{
DBUG_ENTER("sp_rcontext::push_hstack");
DBUG_ASSERT(m_hsp < m_root_parsing_ctx->max_handler_index());
m_hstack[m_hsp++]= h;
DBUG_PRINT("info", ("m_hsp: %d", m_hsp));
DBUG_VOID_RETURN;
}
uint
sp_rcontext::pop_hstack()
{
uint handler;
DBUG_ENTER("sp_rcontext::pop_hstack");
DBUG_ASSERT(m_hsp);
handler= m_hstack[--m_hsp];
DBUG_PRINT("info", ("m_hsp: %d", m_hsp));
DBUG_RETURN(handler);
}
void
sp_rcontext::enter_handler(int hid)
{
DBUG_ENTER("sp_rcontext::enter_handler");
DBUG_ASSERT(m_ihsp < m_root_parsing_ctx->max_handler_index());
m_in_handler[m_ihsp++]= hid;
DBUG_PRINT("info", ("m_ihsp: %d", m_ihsp));
DBUG_VOID_RETURN;
}
void
sp_rcontext::exit_handler()
{
DBUG_ENTER("sp_rcontext::exit_handler");
DBUG_ASSERT(m_ihsp);
m_ihsp-= 1;
DBUG_PRINT("info", ("m_ihsp: %d", m_ihsp));
DBUG_VOID_RETURN;
}
int
sp_rcontext::set_variable(THD *thd, uint var_idx, Item **value)
{
return set_variable(thd, m_var_table->field[var_idx], value);
}
int
sp_rcontext::set_variable(THD *thd, Field *field, Item **value)
{
if (!value)
{
field->set_null();
return 0;
}
return sp_eval_expr(thd, field, value);
}
Item *
sp_rcontext::get_item(uint var_idx)
{
return m_var_items[var_idx];
}
Item **
sp_rcontext::get_item_addr(uint var_idx)
{
return m_var_items + var_idx;
}
/*
*
* sp_cursor
*
*/
sp_cursor::sp_cursor(sp_lex_keeper *lex_keeper, sp_instr_cpush *i)
:m_lex_keeper(lex_keeper),
server_side_cursor(NULL),
m_i(i)
{
/*
currsor can't be stored in QC, so we should prevent opening QC for
try to write results which are absent.
*/
lex_keeper->disable_query_cache();
}
/*
Open an SP cursor
SYNOPSIS
open()
THD Thread handler
RETURN
0 in case of success, -1 otherwise
*/
int
sp_cursor::open(THD *thd)
{
if (server_side_cursor)
{
my_message(ER_SP_CURSOR_ALREADY_OPEN, ER(ER_SP_CURSOR_ALREADY_OPEN),
MYF(0));
return -1;
}
if (mysql_open_cursor(thd, (uint) ALWAYS_MATERIALIZED_CURSOR, &result,
&server_side_cursor))
return -1;
return 0;
}
int
sp_cursor::close(THD *thd)
{
if (! server_side_cursor)
{
my_message(ER_SP_CURSOR_NOT_OPEN, ER(ER_SP_CURSOR_NOT_OPEN), MYF(0));
return -1;
}
destroy();
return 0;
}
void
sp_cursor::destroy()
{
delete server_side_cursor;
server_side_cursor= 0;
}
int
sp_cursor::fetch(THD *thd, List<struct sp_variable> *vars)
{
if (! server_side_cursor)
{
my_message(ER_SP_CURSOR_NOT_OPEN, ER(ER_SP_CURSOR_NOT_OPEN), MYF(0));
return -1;
}
if (vars->elements != result.get_field_count())
{
my_message(ER_SP_WRONG_NO_OF_FETCH_ARGS,
ER(ER_SP_WRONG_NO_OF_FETCH_ARGS), MYF(0));
return -1;
}
result.set_spvar_list(vars);
/* Attempt to fetch one row */
if (server_side_cursor->is_open())
server_side_cursor->fetch(1);
/*
If the cursor was pointing after the last row, the fetch will
close it instead of sending any rows.
*/
if (! server_side_cursor->is_open())
{
my_message(ER_SP_FETCH_NO_DATA, ER(ER_SP_FETCH_NO_DATA), MYF(0));
return -1;
}
return 0;
}
/*
Create an instance of appropriate Item_cache class depending on the
specified type in the callers arena.
SYNOPSIS
thd thread handler
result_type type of the expression
RETURN
Pointer to valid object on success
NULL on error
NOTE
We should create cache items in the callers arena, as they are used
between in several instructions.
*/
Item_cache *
sp_rcontext::create_case_expr_holder(THD *thd, const Item *item)
{
Item_cache *holder;
Query_arena current_arena;
thd->set_n_backup_active_arena(thd->spcont->callers_arena, &current_arena);
holder= Item_cache::get_cache(item);
thd->restore_active_arena(thd->spcont->callers_arena, &current_arena);
return holder;
}
/*
Set CASE expression to the specified value.
SYNOPSIS
thd thread handler
case_expr_id identifier of the CASE expression
case_expr_item a value of the CASE expression
RETURN
FALSE on success
TRUE on error
NOTE
The idea is to reuse Item_cache for the expression of the one CASE
statement. This optimization takes place when there is CASE statement
inside of a loop. So, in other words, we will use the same object on each
iteration instead of creating a new one for each iteration.
TODO
Hypothetically, a type of CASE expression can be different for each
iteration. For instance, this can happen if the expression contains a
session variable (something like @@VAR) and its type is changed from one
iteration to another.
In order to cope with this problem, we check type each time, when we use
already created object. If the type does not match, we re-create Item.
This also can (should?) be optimized.
*/
int
sp_rcontext::set_case_expr(THD *thd, int case_expr_id, Item **case_expr_item_ptr)
{
Item *case_expr_item= sp_prepare_func_item(thd, case_expr_item_ptr);
if (!case_expr_item)
return TRUE;
if (!m_case_expr_holders[case_expr_id] ||
m_case_expr_holders[case_expr_id]->result_type() !=
case_expr_item->result_type())
{
m_case_expr_holders[case_expr_id]=
create_case_expr_holder(thd, case_expr_item);
}
m_case_expr_holders[case_expr_id]->store(case_expr_item);
m_case_expr_holders[case_expr_id]->cache_value();
return FALSE;
}
Item *
sp_rcontext::get_case_expr(int case_expr_id)
{
return m_case_expr_holders[case_expr_id];
}
Item **
sp_rcontext::get_case_expr_addr(int case_expr_id)
{
return (Item**) m_case_expr_holders + case_expr_id;
}
/***************************************************************************
Select_fetch_into_spvars
****************************************************************************/
int Select_fetch_into_spvars::prepare(List<Item> &fields, SELECT_LEX_UNIT *u)
{
/*
Cache the number of columns in the result set in order to easily
return an error if column count does not match value count.
*/
field_count= fields.elements;
return select_result_interceptor::prepare(fields, u);
}
int Select_fetch_into_spvars::send_data(List<Item> &items)
{
List_iterator_fast<struct sp_variable> spvar_iter(*spvar_list);
List_iterator_fast<Item> item_iter(items);
sp_variable_t *spvar;
Item *item;
/* Must be ensured by the caller */
DBUG_ASSERT(spvar_list->elements == items.elements);
/*
Assign the row fetched from a server side cursor to stored
procedure variables.
*/
for (; spvar= spvar_iter++, item= item_iter++; )
{
if (thd->spcont->set_variable(thd, spvar->offset, &item))
return 1;
}
return 0;
}
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