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