cuberite-2a/source/cEvent.cpp

// cEvent.cpp

// Implements the cEvent object representing an OS-specific synchronization primitive that can be waited-for
// Implemented as an Event on Win and as a 1-semaphore on *nix

#include "Globals.h"  // NOTE: MSVC stupidness requires this to be the same across all modules

#include "cEvent.h"





cEvent::cEvent(void)
{
#ifdef _WIN32
	m_Event = CreateEvent( 0, FALSE, FALSE, 0 );
	if (m_Event == NULL)
	{
		LOGERROR("cEvent: cannot create event, GLE = %d. Aborting server.", GetLastError());
		abort();
	}
#else  // *nix
	m_bIsNamed = false;
	m_Event = new sem_t;
	if (sem_init(m_Event, 0, 0))
	{
		LOGWARN("WARNING cEvent: Could not create unnamed semaphore, fallback to named.");
		
		// _X: I'm unconvinced about using sem_unlink() just after a successful sem_open(), it seems wrong - why destroy the object just after creating?
		assert(!"This codepath is really weird, if it is ever used, please check that everything works.");
		
		delete m_Event;
		m_bIsNamed = true;

		char c_Str[64];
		sprintf(c_Str, "cEvent%p", this);
		m_Event = sem_open( c_Str, O_CREAT, 777, 0 );
		if (m_Event == SEM_FAILED)
		{
			LOGERROR("cEvent: Cannot create event, errno = %i. Aborting server.", errno);
			abort();
		}
		else
		{
			if( sem_unlink( c_Str ) != 0 )
			{
				LOGWARN("ERROR: Could not unlink cEvent. (%i)", errno);
			}
		}
	}
#endif  // *nix
}





cEvent::~cEvent()
{
#ifdef _WIN32
	CloseHandle(m_Event);
#else
	if (m_bIsNamed)
	{
		if (sem_close(m_Event) != 0)
		{
			LOGERROR("ERROR: Could not close cEvent. (%i)", errno);
		}
	}
	else
	{
		sem_destroy(m_Event);
		delete m_Event;
	}
#endif
}





void cEvent::Wait(void)
{
#ifdef _WIN32
	DWORD res = WaitForSingleObject(m_Event, INFINITE);
	if (res != WAIT_OBJECT_0)
	{
		LOGWARN("cEvent: waiting for the event failed: %d, GLE = %d. Continuing, but server may be unstable.", res, GetLastError());
	}
#else
	int res = sem_wait(m_Event);
	if (res != 0 )
	{
		LOGWARN("cEvent: waiting for the event failed: %i, errno = %i. Continuing, but server may be unstable.", res, errno);
	}
#endif
}





void cEvent::Set(void)
{
#ifdef _WIN32
	if (SetEvent(m_Event))
	{
		LOGWARN("cEvent: Could not set cEvent: GLE = %d", GetLastError());
	}
#else
	int res = sem_post(m_Event);
	if (res != 0)
	{
		LOGWARN("cEvent: Could not set cEvent: %i, errno = %d", res, errno);
	}
#endif
}