MySQL 5.1: mysql/src/5.1-dbg/include/thr_lock.h Source File
mysql/src/5.1-dbg/include/thr_lock.h

00001 /* Copyright (C) 2000 MySQL AB
00002 
00003    This program is free software; you can redistribute it and/or modify
00004    it under the terms of the GNU General Public License as published by
00005    the Free Software Foundation; either version 2 of the License, or
00006    (at your option) any later version.
00007 
00008    This program is distributed in the hope that it will be useful,
00009    but WITHOUT ANY WARRANTY; without even the implied warranty of
00010    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00011    GNU General Public License for more details.
00012 
00013    You should have received a copy of the GNU General Public License
00014    along with this program; if not, write to the Free Software
00015    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
00016 
00017 /* For use with thr_lock:s */
00018 
00019 #ifndef _thr_lock_h
00020 #define _thr_lock_h
00021 #ifdef  __cplusplus
00022 extern "C" {
00023 #endif
00024 
00025 #include <my_pthread.h>
00026 #include <my_list.h>
00027 
00028 struct st_thr_lock;
00029 extern ulong locks_immediate,locks_waited ;
00030 
00031 enum thr_lock_type { TL_IGNORE=-1,
00032                      TL_UNLOCK,                 /* UNLOCK ANY LOCK */
00033                      TL_READ,                   /* Read lock */
00034                      TL_READ_WITH_SHARED_LOCKS,
00035                      /* High prior. than TL_WRITE. Allow concurrent insert */
00036                      TL_READ_HIGH_PRIORITY,
00037                      /* READ, Don't allow concurrent insert */
00038                      TL_READ_NO_INSERT,
00039                      /* 
00040                         Write lock, but allow other threads to read / write.
00041                         Used by BDB tables in MySQL to mark that someone is
00042                         reading/writing to the table.
00043                       */
00044                      TL_WRITE_ALLOW_WRITE,
00045                      /*
00046                         Write lock, but allow other threads to read.
00047                         Used by ALTER TABLE in MySQL to allow readers
00048                         to use the table until ALTER TABLE is finished.
00049                      */
00050                      TL_WRITE_ALLOW_READ,
00051                      /*
00052                        WRITE lock used by concurrent insert. Will allow
00053                        READ, if one could use concurrent insert on table.
00054                      */
00055                      TL_WRITE_CONCURRENT_INSERT,
00056                      /* Write used by INSERT DELAYED.  Allows READ locks */
00057                      TL_WRITE_DELAYED,
00058                      /* WRITE lock that has lower priority than TL_READ */
00059                      TL_WRITE_LOW_PRIORITY,
00060                      /* Normal WRITE lock */
00061                      TL_WRITE,
00062                      /* Abort new lock request with an error */
00063                      TL_WRITE_ONLY};
00064 
00065 enum enum_thr_lock_result { THR_LOCK_SUCCESS= 0, THR_LOCK_ABORTED= 1,
00066                             THR_LOCK_WAIT_TIMEOUT= 2, THR_LOCK_DEADLOCK= 3 };
00067 
00068 
00069 extern ulong max_write_lock_count;
00070 extern ulong table_lock_wait_timeout;
00071 extern my_bool thr_lock_inited;
00072 extern enum thr_lock_type thr_upgraded_concurrent_insert_lock;
00073 
00074 /*
00075   A description of the thread which owns the lock. The address
00076   of an instance of this structure is used to uniquely identify the thread.
00077 */
00078 
00079 typedef struct st_thr_lock_info
00080 {
00081   pthread_t thread;
00082   ulong thread_id;
00083   ulong n_cursors;
00084 } THR_LOCK_INFO;
00085 
00086 /*
00087   Lock owner identifier. Globally identifies the lock owner within the
00088   thread and among all the threads. The address of an instance of this
00089   structure is used as id.
00090 */
00091 
00092 typedef struct st_thr_lock_owner
00093 {
00094   THR_LOCK_INFO *info;
00095 } THR_LOCK_OWNER;
00096 
00097 
00098 typedef struct st_thr_lock_data {
00099   THR_LOCK_OWNER *owner;
00100   struct st_thr_lock_data *next,**prev;
00101   struct st_thr_lock *lock;
00102   pthread_cond_t *cond;
00103   enum thr_lock_type type;
00104   void *status_param;                   /* Param to status functions */
00105   void *debug_print_param;
00106 } THR_LOCK_DATA;
00107 
00108 struct st_lock_list {
00109   THR_LOCK_DATA *data,**last;
00110 };
00111 
00112 typedef struct st_thr_lock {
00113   LIST list;
00114   pthread_mutex_t mutex;
00115   struct st_lock_list read_wait;
00116   struct st_lock_list read;
00117   struct st_lock_list write_wait;
00118   struct st_lock_list write;
00119   /* write_lock_count is incremented for write locks and reset on read locks */
00120   ulong write_lock_count;
00121   uint read_no_write_count;
00122   void (*get_status)(void*, int);       /* When one gets a lock */
00123   void (*copy_status)(void*,void*);
00124   void (*update_status)(void*);         /* Before release of write */
00125   my_bool (*check_status)(void *);
00126 } THR_LOCK;
00127 
00128 
00129 extern LIST *thr_lock_thread_list;
00130 extern pthread_mutex_t THR_LOCK_lock;
00131 
00132 my_bool init_thr_lock(void);            /* Must be called once/thread */
00133 #define thr_lock_owner_init(owner, info_arg) (owner)->info= (info_arg)
00134 void thr_lock_info_init(THR_LOCK_INFO *info);
00135 void thr_lock_init(THR_LOCK *lock);
00136 void thr_lock_delete(THR_LOCK *lock);
00137 void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data,
00138                         void *status_param);
00139 enum enum_thr_lock_result thr_lock(THR_LOCK_DATA *data,
00140                                    THR_LOCK_OWNER *owner,
00141                                    enum thr_lock_type lock_type);
00142 void thr_unlock(THR_LOCK_DATA *data);
00143 enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data,
00144                                          uint count, THR_LOCK_OWNER *owner);
00145 void thr_multi_unlock(THR_LOCK_DATA **data,uint count);
00146 void thr_abort_locks(THR_LOCK *lock, bool upgrade_lock);
00147 my_bool thr_abort_locks_for_thread(THR_LOCK *lock, pthread_t thread);
00148 void thr_print_locks(void);             /* For debugging */
00149 my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data);
00150 void    thr_downgrade_write_lock(THR_LOCK_DATA *data,
00151                                  enum thr_lock_type new_lock_type);
00152 my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data);
00153 #ifdef  __cplusplus
00154 }
00155 #endif
00156 #endif /* _thr_lock_h */
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