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#if defined(OS_LINUX)
#include <Common/EventFD.h>
#include <Common/Exception.h>
#include <base/defines.h>
#include <sys/eventfd.h>
#include <unistd.h>
namespace DB
{
namespace ErrorCodes
{
extern const int CANNOT_PIPE;
extern const int CANNOT_READ_FROM_SOCKET;
extern const int CANNOT_WRITE_TO_SOCKET;
}
EventFD::EventFD()
{
fd = eventfd(0 /* initval */, 0 /* flags */);
if (fd == -1)
throwFromErrno("Cannot create eventfd", ErrorCodes::CANNOT_PIPE);
}
uint64_t EventFD::read() const
{
uint64_t buf = 0;
while (-1 == ::read(fd, &buf, sizeof(buf)))
{
if (errno == EAGAIN)
break;
if (errno != EINTR)
throwFromErrno("Cannot read from eventfd", ErrorCodes::CANNOT_READ_FROM_SOCKET);
}
return buf;
}
bool EventFD::write(uint64_t increase) const
{
while (-1 == ::write(fd, &increase, sizeof(increase)))
{
if (errno == EAGAIN)
return false;
if (errno != EINTR)
throwFromErrno("Cannot write to eventfd", ErrorCodes::CANNOT_WRITE_TO_SOCKET);
}
return true;
}
EventFD::~EventFD()
{
if (fd != -1)
{
int err = close(fd);
chassert(!err || errno == EINTR);
}
}
}
#endif
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