* Copyright 2006, Haiku, Inc. All Rights Reserved.
* Distributed under the terms of the MIT License.
*
* Authors:
* Axel Dörfler, axeld@pinc-software.de
*/
#ifndef LOCK_H
#define LOCK_H
#include <OS.h>
typedef struct lock {
sem_id sem;
int32 count;
} lock;
static inline status_t
init_lock(struct lock *lock, const char *name)
{
lock->sem = create_sem(0, name);
lock->count = 0;
return lock->sem < B_OK ? lock->sem : B_OK;
}
static inline void
uninit_lock(struct lock *lock)
{
delete_sem(lock->sem);
}
static inline status_t
acquire_lock(struct lock *lock)
{
if (atomic_add(&lock->count, 1) > 0)
return acquire_sem(lock->sem);
return B_OK;
}
static inline status_t
release_lock(struct lock *lock)
{
if (atomic_add(&lock->count, -1) > 1)
return release_sem(lock->sem);
return B_OK;
}
class Autolock {
public:
Autolock(struct lock &lock)
:
fLock(&lock)
{
fStatus = acquire_lock(fLock);
}
~Autolock()
{
if (fStatus == B_OK)
release_lock(fLock);
}
bool
IsLocked() const
{
return fStatus == B_OK;
}
private:
status_t fStatus;
struct lock *fLock;
};
#endif
