add rtt mutex support
This commit is contained in:
geniusgogo
geniusgogo
parent
e0a3ced7ea
commit
bb71850863
|
|
@ -33,6 +33,8 @@
|
|||
** implementation can be overridden at
|
||||
** start-time.
|
||||
**
|
||||
** SQLITE_MUTEX_RTT For multi_threaded applications on rt-thread.
|
||||
**
|
||||
** SQLITE_MUTEX_PTHREADS For multi-threaded applications on Unix.
|
||||
**
|
||||
** SQLITE_MUTEX_W32 For multi-threaded applications on Win32.
|
||||
|
|
@ -45,6 +47,8 @@
|
|||
# define SQLITE_MUTEX_PTHREADS
|
||||
# elif SQLITE_OS_WIN
|
||||
# define SQLITE_MUTEX_W32
|
||||
# elif SQLITE_OS_RTT
|
||||
# define SQLITE_MUTEX_RTT
|
||||
# else
|
||||
# define SQLITE_MUTEX_NOOP
|
||||
# endif
|
||||
|
|
|
|||
|
|
@ -0,0 +1,343 @@
|
|||
/*
|
||||
** 2007 August 28
|
||||
**
|
||||
** 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.
|
||||
**
|
||||
*************************************************************************
|
||||
** This file contains the C functions that implement mutexes for rtthread
|
||||
*/
|
||||
#include "sqliteInt.h"
|
||||
|
||||
/*
|
||||
** The code in this file is only used if we are compiling threadsafe
|
||||
** under rt-thread with rt_mutex.
|
||||
**
|
||||
** Note that this implementation requires a version of rt-thread that
|
||||
** supports recursive mutexes.
|
||||
*/
|
||||
#ifdef SQLITE_MUTEX_RTT
|
||||
|
||||
#include <rtthread.h>
|
||||
|
||||
/*
|
||||
** The sqlite3_mutex.id, sqlite3_mutex.nRef, and sqlite3_mutex.owner fields
|
||||
** are necessary under two condidtions: (1) Debug builds and (2) using
|
||||
** home-grown mutexes. Encapsulate these conditions into a single #define.
|
||||
*/
|
||||
#if defined(SQLITE_DEBUG) || defined(SQLITE_HOMEGROWN_RECURSIVE_MUTEX)
|
||||
# define SQLITE_MUTEX_NREF 1
|
||||
#else
|
||||
# define SQLITE_MUTEX_NREF 0
|
||||
#endif
|
||||
|
||||
/*
|
||||
** Each recursive mutex is an instance of the following structure.
|
||||
*/
|
||||
struct sqlite3_mutex {
|
||||
struct rt_mutex mutex; /* Mutex controlling the lock */
|
||||
#if SQLITE_MUTEX_NREF
|
||||
int id; /* Mutex type */
|
||||
volatile int nRef; /* Number of entrances */
|
||||
volatile rt_thread_t owner; /* Thread that is within this mutex */
|
||||
int trace; /* True to trace changes */
|
||||
#endif
|
||||
};
|
||||
#define RTT_MUTEX_INITIALIZER { 0 }
|
||||
#if SQLITE_MUTEX_NREF
|
||||
#define SQLITE3_MUTEX_INITIALIZER { RTT_MUTEX_INITIALIZER, 0, 0, (rt_thread_t)0, 0 }
|
||||
#else
|
||||
#define SQLITE3_MUTEX_INITIALIZER { RTT_MUTEX_INITIALIZER }
|
||||
#endif
|
||||
|
||||
/*
|
||||
** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routine are
|
||||
** intended for use only inside assert() statements. On some platforms,
|
||||
** there might be race conditions that can cause these routines to
|
||||
** deliver incorrect results. In particular, if rtt_equal() is
|
||||
** not an atomic operation, then these routines might delivery
|
||||
** incorrect results. On most platforms, rtt_equal() is a
|
||||
** comparison of two integers and is therefore atomic. But we are
|
||||
** told that HPUX is not such a platform. If so, then these routines
|
||||
** will not always work correctly on HPUX.
|
||||
**
|
||||
** On those platforms where rtt_equal() is not atomic, SQLite
|
||||
** should be compiled without -DSQLITE_DEBUG and with -DNDEBUG to
|
||||
** make sure no assert() statements are evaluated and hence these
|
||||
** routines are never called.
|
||||
*/
|
||||
#if !defined(NDEBUG) || defined(SQLITE_DEBUG)
|
||||
static int rttMutexHeld(sqlite3_mutex *p){
|
||||
return (p->nRef != 0 && p->owner == rt_thread_self());
|
||||
}
|
||||
static int rttMutexNotheld(sqlite3_mutex *p){
|
||||
return (p->nRef == 0 || p->owner != rt_thread_self());
|
||||
}
|
||||
#endif
|
||||
|
||||
/*
|
||||
** Initialize and deinitialize the mutex subsystem.
|
||||
*/
|
||||
static int rttMutexInit(void){ return SQLITE_OK; }
|
||||
static int rttMutexEnd(void){ return SQLITE_OK; }
|
||||
|
||||
/*
|
||||
** The sqlite3_mutex_alloc() routine allocates a new
|
||||
** mutex and returns a pointer to it. If it returns NULL
|
||||
** that means that a mutex could not be allocated. SQLite
|
||||
** will unwind its stack and return an error. The argument
|
||||
** to sqlite3_mutex_alloc() is one of these integer constants:
|
||||
**
|
||||
** <ul>
|
||||
** <li> SQLITE_MUTEX_FAST
|
||||
** <li> SQLITE_MUTEX_RECURSIVE
|
||||
** <li> SQLITE_MUTEX_STATIC_MASTER
|
||||
** <li> SQLITE_MUTEX_STATIC_MEM
|
||||
** <li> SQLITE_MUTEX_STATIC_MEM2
|
||||
** <li> SQLITE_MUTEX_STATIC_PRNG
|
||||
** <li> SQLITE_MUTEX_STATIC_LRU
|
||||
** <li> SQLITE_MUTEX_STATIC_PMEM
|
||||
** </ul>
|
||||
**
|
||||
** The first two constants cause sqlite3_mutex_alloc() to create
|
||||
** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
|
||||
** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
|
||||
** The mutex implementation does not need to make a distinction
|
||||
** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
|
||||
** not want to. But SQLite will only request a recursive mutex in
|
||||
** cases where it really needs one. If a faster non-recursive mutex
|
||||
** implementation is available on the host platform, the mutex subsystem
|
||||
** might return such a mutex in response to SQLITE_MUTEX_FAST.
|
||||
**
|
||||
** The other allowed parameters to sqlite3_mutex_alloc() each return
|
||||
** a pointer to a static preexisting mutex. Six static mutexes are
|
||||
** used by the current version of SQLite. Future versions of SQLite
|
||||
** may add additional static mutexes. Static mutexes are for internal
|
||||
** use by SQLite only. Applications that use SQLite mutexes should
|
||||
** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
|
||||
** SQLITE_MUTEX_RECURSIVE.
|
||||
**
|
||||
** Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
|
||||
** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
|
||||
** returns a different mutex on every call. But for the static
|
||||
** mutex types, the same mutex is returned on every call that has
|
||||
** the same type number.
|
||||
*/
|
||||
static sqlite3_mutex *rttMutexAlloc(int iType){
|
||||
static sqlite3_mutex staticMutexes[] = {
|
||||
SQLITE3_MUTEX_INITIALIZER,
|
||||
SQLITE3_MUTEX_INITIALIZER,
|
||||
SQLITE3_MUTEX_INITIALIZER,
|
||||
SQLITE3_MUTEX_INITIALIZER,
|
||||
SQLITE3_MUTEX_INITIALIZER,
|
||||
SQLITE3_MUTEX_INITIALIZER
|
||||
};
|
||||
sqlite3_mutex *p;
|
||||
switch( iType ){
|
||||
case SQLITE_MUTEX_RECURSIVE: {
|
||||
p = sqlite3MallocZero( sizeof(*p) );
|
||||
if( p ){
|
||||
/* Use a recursive mutex if it is available */
|
||||
rt_mutex_init(&p->mutex, "sqlmtx", RT_IPC_FLAG_PRIO);
|
||||
#if SQLITE_MUTEX_NREF
|
||||
p->id = iType;
|
||||
#endif
|
||||
}
|
||||
break;
|
||||
}
|
||||
case SQLITE_MUTEX_FAST: {
|
||||
p = sqlite3MallocZero( sizeof(*p) );
|
||||
if( p ){
|
||||
#if SQLITE_MUTEX_NREF
|
||||
p->id = iType;
|
||||
#endif
|
||||
rt_mutex_init(&p->mutex, "sqlmtx", RT_IPC_FLAG_PRIO);
|
||||
}
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
assert( iType-2 >= 0 );
|
||||
assert( iType-2 < ArraySize(staticMutexes) );
|
||||
p = &staticMutexes[iType-2];
|
||||
#if SQLITE_MUTEX_NREF
|
||||
p->id = iType;
|
||||
#endif
|
||||
break;
|
||||
}
|
||||
}
|
||||
return p;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** This routine deallocates a previously
|
||||
** allocated mutex. SQLite is careful to deallocate every
|
||||
** mutex that it allocates.
|
||||
*/
|
||||
static void rttMutexFree(sqlite3_mutex *p){
|
||||
assert( p->nRef==0 );
|
||||
assert( p->id==SQLITE_MUTEX_FAST || p->id==SQLITE_MUTEX_RECURSIVE );
|
||||
rt_mutex_delete(&p->mutex);
|
||||
sqlite3_free(p);
|
||||
}
|
||||
|
||||
/*
|
||||
** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
|
||||
** to enter a mutex. If another thread is already within the mutex,
|
||||
** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
|
||||
** SQLITE_BUSY. The sqlite3_mutex_try() interface returns SQLITE_OK
|
||||
** upon successful entry. Mutexes created using SQLITE_MUTEX_RECURSIVE can
|
||||
** be entered multiple times by the same thread. In such cases the,
|
||||
** mutex must be exited an equal number of times before another thread
|
||||
** can enter. If the same thread tries to enter any other kind of mutex
|
||||
** more than once, the behavior is undefined.
|
||||
*/
|
||||
static void rttMutexEnter(sqlite3_mutex *p){
|
||||
assert( p->id==SQLITE_MUTEX_RECURSIVE || rttMutexNotheld(p) );
|
||||
|
||||
#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
|
||||
/* If recursive mutexes are not available, then we have to grow
|
||||
** our own. This implementation assumes that rtt_equal()
|
||||
** is atomic - that it cannot be deceived into thinking self
|
||||
** and p->owner are equal if p->owner changes between two values
|
||||
** that are not equal to self while the comparison is taking place.
|
||||
** This implementation also assumes a coherent cache - that
|
||||
** separate processes cannot read different values from the same
|
||||
** address at the same time. If either of these two conditions
|
||||
** are not met, then the mutexes will fail and problems will result.
|
||||
*/
|
||||
{
|
||||
rt_thread_t self = rt_thread_self();
|
||||
if( p->nRef>0 && (p->owner == self) ){
|
||||
p->nRef++;
|
||||
}else{
|
||||
rt_mutex_take(&p->mutex, RT_WAITING_FOREVER);
|
||||
assert( p->nRef==0 );
|
||||
p->owner = self;
|
||||
p->nRef = 1;
|
||||
}
|
||||
}
|
||||
#else
|
||||
/* Use the built-in recursive mutexes if they are available.
|
||||
*/
|
||||
rt_mutex_take(&p->mutex, RT_WAITING_FOREVER);
|
||||
#if SQLITE_MUTEX_NREF
|
||||
assert( p->nRef>0 || p->owner==0 );
|
||||
p->owner = rt_thread_self();
|
||||
p->nRef++;
|
||||
#endif
|
||||
#endif
|
||||
|
||||
#ifdef SQLITE_DEBUG
|
||||
if( p->trace ){
|
||||
rt_kprintf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
static int rttMutexTry(sqlite3_mutex *p){
|
||||
int rc;
|
||||
assert( p->id==SQLITE_MUTEX_RECURSIVE || rttMutexNotheld(p) );
|
||||
|
||||
#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
|
||||
/* If recursive mutexes are not available, then we have to grow
|
||||
** our own. This implementation assumes that rtt_equal()
|
||||
** is atomic - that it cannot be deceived into thinking self
|
||||
** and p->owner are equal if p->owner changes between two values
|
||||
** that are not equal to self while the comparison is taking place.
|
||||
** This implementation also assumes a coherent cache - that
|
||||
** separate processes cannot read different values from the same
|
||||
** address at the same time. If either of these two conditions
|
||||
** are not met, then the mutexes will fail and problems will result.
|
||||
*/
|
||||
{
|
||||
rt_thread_t self = rt_thread_self();
|
||||
if( p->nRef>0 && (p->owner == self) ){
|
||||
p->nRef++;
|
||||
rc = SQLITE_OK;
|
||||
}else if( rt_mutex_take(&p->mutex, RT_WAITING_NO)==RT_EOK ){
|
||||
assert( p->nRef==0 );
|
||||
p->owner = self;
|
||||
p->nRef = 1;
|
||||
rc = SQLITE_OK;
|
||||
}else{
|
||||
rc = SQLITE_BUSY;
|
||||
}
|
||||
}
|
||||
#else
|
||||
/* Use the built-in recursive mutexes if they are available.
|
||||
*/
|
||||
if( rt_mutex_take(&p->mutex, RT_WAITING_NO)==RT_EOK ){
|
||||
#if SQLITE_MUTEX_NREF
|
||||
p->owner = rt_thread_self();
|
||||
p->nRef++;
|
||||
#endif
|
||||
rc = SQLITE_OK;
|
||||
}else{
|
||||
rc = SQLITE_BUSY;
|
||||
}
|
||||
#endif
|
||||
|
||||
#ifdef SQLITE_DEBUG
|
||||
if( rc==SQLITE_OK && p->trace ){
|
||||
rt_kprintf("enter mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
|
||||
}
|
||||
#endif
|
||||
return rc;
|
||||
}
|
||||
|
||||
/*
|
||||
** The sqlite3_mutex_leave() routine exits a mutex that was
|
||||
** previously entered by the same thread. The behavior
|
||||
** is undefined if the mutex is not currently entered or
|
||||
** is not currently allocated. SQLite will never do either.
|
||||
*/
|
||||
static void rttMutexLeave(sqlite3_mutex *p){
|
||||
assert( rttMutexHeld(p) );
|
||||
#if SQLITE_MUTEX_NREF
|
||||
p->nRef--;
|
||||
if( p->nRef==0 ) p->owner = 0;
|
||||
#endif
|
||||
assert( p->nRef==0 || p->id==SQLITE_MUTEX_RECURSIVE );
|
||||
|
||||
#ifdef SQLITE_HOMEGROWN_RECURSIVE_MUTEX
|
||||
if( p->nRef==0 ){
|
||||
rt_mutex_release(&p->mutex);
|
||||
}
|
||||
#else
|
||||
rt_mutex_release(&p->mutex);
|
||||
#endif
|
||||
|
||||
#ifdef SQLITE_DEBUG
|
||||
if( p->trace ){
|
||||
rt_kprintf("leave mutex %p (%d) with nRef=%d\n", p, p->trace, p->nRef);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
|
||||
sqlite3_mutex_methods const *sqlite3DefaultMutex(void){
|
||||
static const sqlite3_mutex_methods sMutex = {
|
||||
rttMutexInit,
|
||||
rttMutexEnd,
|
||||
rttMutexAlloc,
|
||||
rttMutexFree,
|
||||
rttMutexEnter,
|
||||
rttMutexTry,
|
||||
rttMutexLeave,
|
||||
#ifdef SQLITE_DEBUG
|
||||
rttMutexHeld,
|
||||
rttMutexNotheld
|
||||
#else
|
||||
0,
|
||||
0
|
||||
#endif
|
||||
};
|
||||
|
||||
return &sMutex;
|
||||
}
|
||||
|
||||
#endif /* SQLITE_MUTEX_RTT */
|
||||
|
||||
Loading…
Reference in New Issue