Current File : //usr/include/mysql/mysql/service_locking.h
/*
Copyright (c) 2015, 2023, Oracle and/or its affiliates.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.
This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation. The authors of MySQL hereby grant you an additional
permission to link the program and your derivative works with the
separately licensed software that they have included with MySQL.
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, version 2.0, 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
*/
#ifndef SERVICE_LOCKING_INCLUDED
#define SERVICE_LOCKING_INCLUDED
/*
This service provides support for taking read/write locks.
It is intended for use with fabric, but it is still a general
service. The locks are in a separate namespace from other
locks in the server, and there is also no interactions with
transactions (i.e. locks are not released on commit/abort).
These locks are implemented using the metadata lock (MDL) subsystem
and thus deadlocks involving locking service locks and other types
of metadata will be detected using the MDL deadlock detector.
*/
#ifdef __cplusplus
class THD;
#define MYSQL_THD THD*
#else
#define MYSQL_THD void*
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
Types of locking service locks.
LOCKING_SERVICE_READ is compatible with LOCKING_SERVICE_READ.
All other combinations are incompatible.
*/
enum enum_locking_service_lock_type
{ LOCKING_SERVICE_READ, LOCKING_SERVICE_WRITE };
extern struct mysql_locking_service_st {
/**
Acquire locking service locks.
@param opaque_thd Thread handle. If NULL, current_thd will be used.
@param lock_namespace Namespace of the locks to acquire.
@param lock_names Array of names of the locks to acquire.
@param lock_num Number of elements in 'lock_names'.
@param lock_type Lock type to acquire. LOCKING_SERVICE_READ or _WRITE.
@param lock_timeout Number of seconds to wait before giving up.
@retval 1 Acquisition failed, error has been reported.
@retval 0 Acquisition successful, all locks acquired.
@note both lock_namespace and lock_names are limited to 64 characters max.
Names are compared using binary comparison.
*/
int (*mysql_acquire_locks)(MYSQL_THD opaque_thd, const char* lock_namespace,
const char**lock_names, size_t lock_num,
enum enum_locking_service_lock_type lock_type,
unsigned long lock_timeout);
/**
Release all lock service locks taken by the given connection
in the given namespace.
@param opaque_thd Thread handle. If NULL, current_thd will be used.
@param lock_namespace Namespace of the locks to release.
@retval 1 Release failed, error has been reported.
@retval 0 Release successful, all locks acquired.
*/
int (*mysql_release_locks)(MYSQL_THD opaque_thd, const char* lock_namespace);
} *mysql_locking_service;
#ifdef MYSQL_DYNAMIC_PLUGIN
#define mysql_acquire_locking_service_locks(_THD, _NAMESPACE, _NAMES, _NUM, \
_TYPE, _TIMEOUT) \
mysql_locking_service->mysql_acquire_locks(_THD, _NAMESPACE, _NAMES, _NUM, \
_TYPE, _TIMEOUT)
#define mysql_release_locking_service_locks(_THD, _NAMESPACE) \
mysql_locking_service->mysql_release_locks(_THD, _NAMESPACE)
#else
int mysql_acquire_locking_service_locks(MYSQL_THD opaque_thd,
const char* lock_namespace,
const char**lock_names,
size_t lock_num,
enum enum_locking_service_lock_type lock_type,
unsigned long lock_timeout);
int mysql_release_locking_service_locks(MYSQL_THD opaque_thd,
const char* lock_namespace);
#endif /* MYSQL_DYNAMIC_PLUGIN */
#ifdef __cplusplus
}
#endif
#endif /* SERVICE_LOCKING_INCLUDED */
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