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/* Copyright (C) 2000 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
/* For use with thr_locks */
#pragma once
#include <boost/thread/mutex.hpp>
#include <boost/thread/shared_mutex.hpp>
#include <boost/thread/condition_variable.hpp>
#include <drizzled/visibility.h>
#include <drizzled/common_fwd.h>
namespace drizzled {
extern uint64_t max_write_lock_count;
extern uint64_t table_lock_wait_timeout;
enum thr_lock_type
{
TL_IGNORE=-1,
/* UNLOCK ANY LOCK */
TL_UNLOCK,
/* Read lock */
TL_READ,
TL_READ_WITH_SHARED_LOCKS,
/* READ, Don't allow concurrent insert */
TL_READ_NO_INSERT,
/*
Write lock, but allow other threads to read / write.
Used by BDB tables in MySQL to mark that someone is
reading/writing to the table.
*/
TL_WRITE_ALLOW_WRITE,
/*
Write lock, but allow other threads to read.
Used by ALTER TABLE in MySQL to allow readers
to use the table until ALTER TABLE is finished.
*/
TL_WRITE_ALLOW_READ,
/*
WRITE lock used by concurrent insert. Will allow
READ, if one could use concurrent insert on table.
*/
TL_WRITE_CONCURRENT_INSERT,
/*
parser only! Late bound low_priority flag.
At open_tables() becomes thd->update_lock_default.
*/
TL_WRITE_DEFAULT,
/* Normal WRITE lock */
TL_WRITE,
/* Abort new lock request with an error */
TL_WRITE_ONLY
};
enum enum_thr_lock_result
{
THR_LOCK_SUCCESS= 0,
THR_LOCK_ABORTED= 1,
THR_LOCK_WAIT_TIMEOUT= 2,
THR_LOCK_DEADLOCK= 3
};
/*
A description of the thread which owns the lock. The address
of an instance of this structure is used to uniquely identify the thread.
*/
struct THR_LOCK_INFO
{
uint64_t thread_id;
uint32_t n_cursors;
THR_LOCK_INFO() :
thread_id(0),
n_cursors(0)
{ }
void init();
};
/*
Lock owner identifier. Globally identifies the lock owner within the
thread and among all the threads. The address of an instance of this
structure is used as id.
*/
struct THR_LOCK_OWNER
{
THR_LOCK_INFO *info;
THR_LOCK_OWNER() :
info(NULL)
{ }
};
struct THR_LOCK;
struct THR_LOCK_DATA;
struct DRIZZLED_API THR_LOCK_DATA
{
THR_LOCK_OWNER *owner;
struct THR_LOCK_DATA *next,**prev;
struct THR_LOCK *lock;
boost::condition_variable_any *cond;
enum thr_lock_type type;
void *status_param; /* Param to status functions */
THR_LOCK_DATA() :
owner(0),
next(0),
prev(0),
lock(0),
cond(0),
type(TL_UNLOCK),
status_param(0)
{ }
void init(THR_LOCK*, void *status_param= NULL);
};
struct st_lock_list
{
THR_LOCK_DATA *data,**last;
st_lock_list() :
data(0),
last(0)
{ }
};
struct THR_LOCK
{
private:
boost::mutex mutex;
public:
struct st_lock_list read_wait;
struct st_lock_list read;
struct st_lock_list write_wait;
struct st_lock_list write;
/* write_lock_count is incremented for write locks and reset on read locks */
uint32_t write_lock_count;
uint32_t read_no_write_count;
THR_LOCK() :
write_lock_count(0),
read_no_write_count(0)
{ }
void abort_locks();
bool abort_locks_for_thread(uint64_t thread);
void lock()
{
mutex.lock();
}
void unlock()
{
mutex.unlock();
}
boost::mutex *native_handle()
{
return &mutex;
}
};
DRIZZLED_API void thr_lock_init(THR_LOCK *lock);
enum_thr_lock_result thr_multi_lock(Session&, THR_LOCK_DATA**, uint32_t count, THR_LOCK_OWNER*);
void thr_multi_unlock(THR_LOCK_DATA**, uint32_t count);
} /* namespace drizzled */
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