ardupilot/libraries/AP_HAL_SITL/Semaphores.cpp

80 lines
1.8 KiB
C++

#include <AP_HAL/AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
#include "Semaphores.h"
#include "Scheduler.h"
extern const AP_HAL::HAL& hal;
using namespace HALSITL;
// construct a semaphore
Semaphore::Semaphore()
{
pthread_mutexattr_t attr;
pthread_mutexattr_init(&attr);
pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(&_lock, &attr);
}
bool Semaphore::give()
{
take_count--;
if (pthread_mutex_unlock(&_lock) != 0) {
AP_HAL::panic("Bad semaphore usage");
}
if (take_count == 0) {
owner = (pthread_t)-1;
}
return true;
}
void Semaphore::check_owner() const
{
// should probably make sure we're holding the semaphore here....
if (owner != pthread_self()) {
AP_HAL::panic("Wrong owner");
}
}
bool Semaphore::take(uint32_t timeout_ms)
{
if (timeout_ms == HAL_SEMAPHORE_BLOCK_FOREVER) {
if (pthread_mutex_lock(&_lock) == 0) {
owner = pthread_self();
take_count++;
return true;
}
return false;
}
if (take_nonblocking()) {
owner = pthread_self();
return true;
}
uint64_t start = AP_HAL::micros64();
do {
Scheduler::from(hal.scheduler)->set_in_semaphore_take_wait(true);
hal.scheduler->delay_microseconds(200);
Scheduler::from(hal.scheduler)->set_in_semaphore_take_wait(false);
if (take_nonblocking()) {
owner = pthread_self();
return true;
}
} while ((AP_HAL::micros64() - start) < timeout_ms * 1000);
return false;
}
bool Semaphore::take_nonblocking()
{
if (pthread_mutex_trylock(&_lock) == 0) {
owner = pthread_self();
take_count++;
return true;
}
return false;
}
#endif // CONFIG_HAL_BOARD