OW_MutexImpl.cpp

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#include "OW_config.h"
#include "OW_MutexImpl.hpp"
#include <cerrno>
#include <cassert>

namespace OW_NAMESPACE
{

namespace MutexImpl
{

int
createMutex(Mutex_t& handle)
{
#if defined (OW_USE_PTHREAD)
   pthread_mutexattr_t attr;
   int res = pthread_mutexattr_init(&attr);
   assert(res == 0);
   if (res != 0)
   {
      return -1;
   }
 
#if defined(OW_HAVE_PTHREAD_MUTEXATTR_SETTYPE)
   res = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
   assert(res == 0);
   if (res != 0)
   {
      pthread_mutexattr_destroy(&attr);
      return -1;
   }
#endif
 
   res = pthread_mutex_init(&handle.mutex, &attr);
   pthread_mutexattr_destroy(&attr);
   if (res != 0)
   {
      return -1;
   }
 
#if !defined(OW_HAVE_PTHREAD_MUTEXATTR_SETTYPE)
   res = pthread_cond_init(&handle.unlocked, 0);
   if (res != 0)
   {
      pthread_mutex_destroy(&handle.mutex);
      return -1;
   }
   
   handle.valid_id = false;
   handle.count = 0;
#endif
   return 0;
#elif defined (OW_WIN32)
   handle = new CRITICAL_SECTION;
   assert(handle);
   InitializeCriticalSection(handle);
   return 0;
#else
#error "port me!"
#endif
}
int
destroyMutex(Mutex_t& handle)
{
#if defined (OW_USE_PTHREAD)
   switch (pthread_mutex_destroy(&handle.mutex))
   {
      case 0:
         break;
      case EBUSY:
         return -1;
         break;
      default:
         return -2;
   }
   int res = 0;
#if !defined(OW_HAVE_PTHREAD_MUTEXATTR_SETTYPE)
   res = pthread_cond_destroy(&handle.unlocked);
   assert(res == 0);
#endif
   return res;
#elif defined(OW_WIN32)
   if(handle)
   {
      DeleteCriticalSection(handle);
      delete handle;
      handle = 0;
   }
   return 0;
#else
#error "port me!"
#endif
}
int
acquireMutex(Mutex_t& handle)
{
#if defined (OW_USE_PTHREAD)
   int res = pthread_mutex_lock(&handle.mutex);
   assert(res == 0);
 
#if !defined(OW_HAVE_PTHREAD_MUTEXATTR_SETTYPE)
   pthread_t tid = pthread_self();
   if (handle.valid_id && pthread_equal(handle.thread_id, tid))
   {
      ++handle.count;
   }
   else
   {
      while (handle.valid_id)
      {
         res = pthread_cond_wait(&handle.unlocked, &handle.mutex);
         assert(res == 0);
      }
 
      handle.thread_id = tid;
      handle.valid_id = true;
      handle.count = 1;
   }
 
   res = pthread_mutex_unlock(&handle.mutex);
   assert(res == 0);
#endif
   return res;
#elif defined(OW_WIN32)
   EnterCriticalSection(handle);
   return 0;
#else
#error "port me!"
#endif
}
int
releaseMutex(Mutex_t& handle)
{
#if defined (OW_USE_PTHREAD)
#if defined(OW_HAVE_PTHREAD_MUTEXATTR_SETTYPE)
   int res = pthread_mutex_unlock(&handle.mutex);
   assert(res == 0);
   return res;
#else
   int res = 0;
   res = pthread_mutex_lock(&handle.mutex);
   assert(res == 0);
 
   pthread_t tid = pthread_self();
   if (handle.valid_id && !pthread_equal(handle.thread_id, tid))
   {
      res = pthread_mutex_unlock(&handle.mutex);
      assert(res == 0);
      return -1;
   }
 
   if (--handle.count == 0)
   {
      assert(handle.valid_id);
      handle.valid_id = false;
 
      res = pthread_cond_signal(&handle.unlocked);
      assert(res == 0);
   }
 
   res = pthread_mutex_unlock(&handle.mutex);
   assert(res == 0);
   return res;
#endif
#elif defined (OW_WIN32)
   LeaveCriticalSection(handle);
   return 0;
#else
#error "port me!"
#endif
}

} // end namespace MutexImpl
} // end namespace OW_NAMESPACE

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