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/*****************************************************************************
Copyright (c) 1997, 2012, Oracle and/or its affiliates. All Rights Reserved.
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 Street, Suite 500, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file include/read0read.ic
Cursor read
Created 2/16/1997 Heikki Tuuri
*******************************************************/
#include "trx0sys.h"
#ifdef UNIV_DEBUG
/*********************************************************************//**
Validates a read view object. */
static
bool
read_view_validate(
/*===============*/
const read_view_t* view) /*!< in: view to validate */
{
ut_ad(mutex_own(&trx_sys->mutex));
/* Check that the view->trx_ids array is in descending order. */
for (ulint i = 1; i < view->n_trx_ids; ++i) {
ut_a(view->trx_ids[i] < view->trx_ids[i - 1]);
}
return(true);
}
/** Functor to validate the view list. */
struct ViewCheck {
ViewCheck() : m_prev_view(0) { }
void operator()(const read_view_t* view)
{
ut_a(m_prev_view == NULL
|| m_prev_view->low_limit_no >= view->low_limit_no);
m_prev_view = view;
}
const read_view_t* m_prev_view;
};
/*********************************************************************//**
Validates a read view list. */
static
bool
read_view_list_validate(void)
/*=========================*/
{
ut_ad(mutex_own(&trx_sys->mutex));
ut_list_map(trx_sys->view_list, &read_view_t::view_list, ViewCheck());
return(true);
}
#endif /* UNIV_DEBUG */
/*********************************************************************//**
Checks if a read view sees the specified transaction.
@return true if sees */
UNIV_INLINE
bool
read_view_sees_trx_id(
/*==================*/
const read_view_t* view, /*!< in: read view */
trx_id_t trx_id) /*!< in: trx id */
{
if (trx_id < view->up_limit_id) {
return(true);
} else if (trx_id >= view->low_limit_id) {
return(false);
} else {
ulint lower = 0;
ulint upper = view->n_trx_ids - 1;
ut_a(view->n_trx_ids > 0);
do {
ulint mid = (lower + upper) >> 1;
trx_id_t mid_id = view->trx_ids[mid];
if (mid_id == trx_id) {
return(FALSE);
} else if (mid_id < trx_id) {
if (mid > 0) {
upper = mid - 1;
} else {
break;
}
} else {
lower = mid + 1;
}
} while (lower <= upper);
}
return(true);
}
/*********************************************************************//**
Remove a read view from the trx_sys->view_list. */
UNIV_INLINE
void
read_view_remove(
/*=============*/
read_view_t* view, /*!< in: read view, can be 0 */
bool own_mutex) /*!< in: true if caller owns the
trx_sys_t::mutex */
{
if (view != 0) {
if (!own_mutex) {
mutex_enter(&trx_sys->mutex);
}
ut_ad(read_view_validate(view));
UT_LIST_REMOVE(view_list, trx_sys->view_list, view);
ut_ad(read_view_list_validate());
if (!own_mutex) {
mutex_exit(&trx_sys->mutex);
}
}
}
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