source/core/unix/semaphore.cpp

   1 #include <sys/time.h>
   2 #include <cerrno>
   3 #include <msp/core/systemerror.h>
   4 #include <msp/time/rawtime_private.h>
   5 #include <msp/time/timestamp.h>
   6 #include <msp/time/utils.h>
   7 #include "mutex.h"
   8 #include "mutex_private.h"
   9 #include "semaphore.h"
  10
  11 namespace Msp {
  12
  13 struct Semaphore::Private
  14 {
  15         Mutex mutex;
  16         pthread_cond_t cond;
  17         unsigned limit;
  18         unsigned count;
  19 };
  20
  21
  22 Semaphore::Semaphore(unsigned limit):
  23         priv(new Private)
  24 {
  25         pthread_cond_init(&priv->cond, 0);
  26         priv->limit = limit;
  27         priv->count = 0;
  28 }
  29
  30 Semaphore::~Semaphore()
  31 {
  32         pthread_cond_destroy(&priv->cond);
  33         delete priv;
  34 }
  35
  36 void Semaphore::signal()
  37 {
  38         MutexLock mlock(priv->mutex);
  39         if(priv->count<priv->limit)
  40                 ++priv->count;
  41         if(int err = pthread_cond_signal(&priv->cond))
  42                 throw system_error("pthread_cond_signal", err);
  43 }
  44
  45 void Semaphore::wait()
  46 {
  47         MutexLock mlock(priv->mutex);
  48         while(!priv->count)
  49                 if(int err = pthread_cond_wait(&priv->cond, &priv->mutex.priv->mutex))
  50                         throw system_error("pthread_cond_wait", err);
  51         --priv->count;
  52 }
  53
  54 bool Semaphore::wait(const Time::TimeDelta &d)
  55 {
  56         timespec timeout = Time::rawtime_to_timespec((Time::now()+d).raw());
  57
  58         int err = pthread_cond_timedwait(&priv->cond, &priv->mutex.priv->mutex, &timeout);
  59         if(err && err!=ETIMEDOUT)
  60                 throw system_error("pthread_cond_timedwait", err);
  61         return err==0;
  62 }
  63
  64 } // namespace Msp