source/core/semaphore.cpp

   1 #ifdef WIN32
   2 #include <windows.h>
   3 #else
   4 #include <sys/time.h>
   5 #include <cerrno>
   6 #endif
   7 #include <msp/time/rawtime_private.h>
   8 #include <msp/time/timestamp.h>
   9 #include <msp/time/units.h>
  10 #include <msp/time/utils.h>
  11 #include "mutex_private.h"
  12 #include "semaphore.h"
  13 #include "systemerror.h"
  14
  15 namespace Msp {
  16
  17 struct Semaphore::Private
  18 {
  19 #ifdef WIN32
  20         HANDLE handle;
  21 #else
  22         Mutex mutex;
  23         pthread_cond_t cond;
  24         unsigned limit;
  25         unsigned count;
  26 #endif
  27 };
  28
  29
  30 Semaphore::Semaphore(unsigned limit):
  31         priv(new Private)
  32 {
  33 #ifdef WIN32
  34         priv->handle = CreateSemaphore(0, 0, limit, 0);
  35 #else
  36         pthread_cond_init(&priv->cond, 0);
  37         priv->limit = limit;
  38         priv->count = 0;
  39 #endif
  40 }
  41
  42 Semaphore::~Semaphore()
  43 {
  44 #ifdef WIN32
  45         CloseHandle(priv->handle);
  46 #else
  47         pthread_cond_destroy(&priv->cond);
  48 #endif
  49         delete priv;
  50 }
  51
  52 void Semaphore::signal()
  53 {
  54 #ifdef WIN32
  55         if(!ReleaseSemaphore(priv->handle, 1, 0))
  56                 throw system_error("Semaphore::signal");
  57 #else
  58         MutexLock mlock(priv->mutex);
  59         if(priv->count<priv->limit)
  60                 ++priv->count;
  61         if(int err = pthread_cond_signal(&priv->cond))
  62                 throw system_error("Semaphore::signal", err);
  63 #endif
  64 }
  65
  66 void Semaphore::wait()
  67 {
  68 #ifdef WIN32
  69         DWORD ret = WaitForSingleObject(priv->handle, INFINITE);
  70         if(ret==WAIT_FAILED)
  71                 throw system_error("Semaphore::wait");
  72 #else
  73         MutexLock mlock(priv->mutex);
  74         while(!priv->count)
  75                 if(int err = pthread_cond_wait(&priv->cond, &priv->mutex.priv->mutex))
  76                         throw system_error("Semaphore::wait", err);
  77         --priv->count;
  78 #endif
  79 }
  80
  81 bool Semaphore::wait(const Time::TimeDelta &d)
  82 {
  83 #ifdef WIN32
  84         DWORD ret = WaitForSingleObject(priv->handle, (DWORD)(d/Time::usec));
  85         if(ret==WAIT_FAILED)
  86                 throw system_error("Semaphore::wait");
  87         return ret==WAIT_OBJECT_0;
  88 #else
  89         timespec timeout = Time::rawtime_to_timespec((Time::now()+d).raw());
  90
  91         int err = pthread_cond_timedwait(&priv->cond, &priv->mutex.priv->mutex, &timeout);
  92         if(err && err!=ETIMEDOUT)
  93                 throw system_error("Semaphore::wait", err);
  94         return err==0;
  95 #endif
  96 }
  97
  98 } // namespace Msp