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 = 1;
  18         unsigned count = 0;
  19 };
  20
  21
  22 Semaphore::Semaphore(unsigned limit):
  23         priv(new Private)
  24 {
  25         pthread_cond_init(&priv->cond, nullptr);
  26         priv->limit = limit;
  27 }
  28
  29 Semaphore::~Semaphore()
  30 {
  31         pthread_cond_destroy(&priv->cond);
  32         delete priv;
  33 }
  34
  35 void Semaphore::signal()
  36 {
  37         MutexLock mlock(priv->mutex);
  38         if(priv->count<priv->limit)
  39                 ++priv->count;
  40         if(int err = pthread_cond_signal(&priv->cond))
  41                 throw system_error("pthread_cond_signal", err);
  42 }
  43
  44 void Semaphore::wait()
  45 {
  46         MutexLock mlock(priv->mutex);
  47         while(!priv->count)
  48                 if(int err = pthread_cond_wait(&priv->cond, &priv->mutex.priv->mutex))
  49                         throw system_error("pthread_cond_wait", err);
  50         --priv->count;
  51 }
  52
  53 bool Semaphore::wait(const Time::TimeDelta &d)
  54 {
  55         timespec timeout = Time::rawtime_to_timespec((Time::now()+d).raw());
  56
  57         int err = pthread_cond_timedwait(&priv->cond, &priv->mutex.priv->mutex, &timeout);
  58         if(err && err!=ETIMEDOUT)
  59                 throw system_error("pthread_cond_timedwait", err);
  60         return err==0;
  61 }
  62
  63 } // namespace Msp