sqlite/ext/lsm1/lsm_mutex.c
drh a0b7ffb184 Import the LSM code from SQLite4 for use in an experimental virtual table.
NB: This is a speculative experiment and could easily result in a dead-end
branch.

FossilOrigin-Name: 3d930501a2acb7f20932cfeb4e3fe308b4569cd6
2015-11-16 16:00:22 +00:00

89 lines
2.3 KiB
C

/*
** 2012-01-30
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
** Mutex functions for LSM.
*/
#include "lsmInt.h"
/*
** Allocate a new mutex.
*/
int lsmMutexNew(lsm_env *pEnv, lsm_mutex **ppNew){
return pEnv->xMutexNew(pEnv, ppNew);
}
/*
** Return a handle for one of the static mutexes.
*/
int lsmMutexStatic(lsm_env *pEnv, int iMutex, lsm_mutex **ppStatic){
return pEnv->xMutexStatic(pEnv, iMutex, ppStatic);
}
/*
** Free a mutex allocated by lsmMutexNew().
*/
void lsmMutexDel(lsm_env *pEnv, lsm_mutex *pMutex){
if( pMutex ) pEnv->xMutexDel(pMutex);
}
/*
** Enter a mutex.
*/
void lsmMutexEnter(lsm_env *pEnv, lsm_mutex *pMutex){
pEnv->xMutexEnter(pMutex);
}
/*
** Attempt to enter a mutex, but do not block. If successful, return zero.
** Otherwise, if the mutex is already held by some other thread and is not
** entered, return non zero.
**
** Each successful call to this function must be matched by a call to
** lsmMutexLeave().
*/
int lsmMutexTry(lsm_env *pEnv, lsm_mutex *pMutex){
return pEnv->xMutexTry(pMutex);
}
/*
** Leave a mutex.
*/
void lsmMutexLeave(lsm_env *pEnv, lsm_mutex *pMutex){
pEnv->xMutexLeave(pMutex);
}
#ifndef NDEBUG
/*
** Return non-zero if the mutex passed as the second argument is held
** by the calling thread, or zero otherwise. If the implementation is not
** able to tell if the mutex is held by the caller, it should return
** non-zero.
**
** This function is only used as part of assert() statements.
*/
int lsmMutexHeld(lsm_env *pEnv, lsm_mutex *pMutex){
return pEnv->xMutexHeld ? pEnv->xMutexHeld(pMutex) : 1;
}
/*
** Return non-zero if the mutex passed as the second argument is not
** held by the calling thread, or zero otherwise. If the implementation
** is not able to tell if the mutex is held by the caller, it should
** return non-zero.
**
** This function is only used as part of assert() statements.
*/
int lsmMutexNotHeld(lsm_env *pEnv, lsm_mutex *pMutex){
return pEnv->xMutexNotHeld ? pEnv->xMutexNotHeld(pMutex) : 1;
}
#endif