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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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* For use with thr_lock:s */
#ifndef _thr_lock_h
#define _thr_lock_h
#ifdef __cplusplus
extern "C" {
#endif
#include <my_pthread.h>
#include <my_list.h>
struct st_thr_lock;
extern ulong locks_immediate,locks_waited ;
extern pthread_mutex_t THR_LOCK_lock;
enum thr_lock_type { TL_IGNORE=-1,
TL_UNLOCK, /* UNLOCK ANY LOCK */
TL_READ, /* Read lock */
TL_READ_WITH_SHARED_LOCKS,
/* High prior. than TL_WRITE. Allow concurrent insert */
TL_READ_HIGH_PRIORITY,
/* 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,
/* Write used by INSERT DELAYED. Allows READ locks */
TL_WRITE_DELAYED,
/*
parser only! Late bound low_priority flag.
At open_tables() becomes thd->update_lock_default.
*/
TL_WRITE_DEFAULT,
/* WRITE lock that has lower priority than TL_READ */
TL_WRITE_LOW_PRIORITY,
/* 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 };
extern ulong max_write_lock_count;
extern ulong table_lock_wait_timeout;
extern my_bool thr_lock_inited;
extern enum thr_lock_type thr_upgraded_concurrent_insert_lock;
/*
A description of the thread which owns the lock. The address
of an instance of this structure is used to uniquely identify the thread.
*/
typedef struct st_thr_lock_info
{
pthread_t thread;
my_thread_id thread_id;
ulong n_cursors;
} THR_LOCK_INFO;
/*
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.
*/
typedef struct st_thr_lock_owner
{
THR_LOCK_INFO *info;
} THR_LOCK_OWNER;
typedef struct st_thr_lock_data {
THR_LOCK_OWNER *owner;
struct st_thr_lock_data *next,**prev;
struct st_thr_lock *lock;
pthread_cond_t *cond;
enum thr_lock_type type;
void *status_param; /* Param to status functions */
void *debug_print_param;
} THR_LOCK_DATA;
struct st_lock_list {
THR_LOCK_DATA *data,**last;
};
typedef struct st_thr_lock {
LIST list;
pthread_mutex_t mutex;
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 */
ulong write_lock_count;
uint read_no_write_count;
void (*get_status)(void*, int); /* When one gets a lock */
void (*copy_status)(void*,void*);
void (*update_status)(void*); /* Before release of write */
void (*restore_status)(void*); /* Before release of read */
my_bool (*check_status)(void *);
} THR_LOCK;
extern LIST *thr_lock_thread_list;
my_bool init_thr_lock(void); /* Must be called once/thread */
#define thr_lock_owner_init(owner, info_arg) (owner)->info= (info_arg)
void thr_lock_info_init(THR_LOCK_INFO *info);
void thr_lock_init(THR_LOCK *lock);
void thr_lock_delete(THR_LOCK *lock);
void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data,
void *status_param);
enum enum_thr_lock_result thr_lock(THR_LOCK_DATA *data,
THR_LOCK_OWNER *owner,
enum thr_lock_type lock_type);
void thr_unlock(THR_LOCK_DATA *data);
enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data,
uint count, THR_LOCK_OWNER *owner);
void thr_multi_unlock(THR_LOCK_DATA **data,uint count);
void thr_abort_locks(THR_LOCK *lock, my_bool upgrade_lock);
my_bool thr_abort_locks_for_thread(THR_LOCK *lock, my_thread_id thread);
void thr_print_locks(void); /* For debugging */
my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data);
void thr_downgrade_write_lock(THR_LOCK_DATA *data,
enum thr_lock_type new_lock_type);
my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data);
#ifdef __cplusplus
}
#endif
#endif /* _thr_lock_h */
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