EventFile.cxx

// cosmos
#include <cosmos/error/ApiError.hxx>
#include <cosmos/error/RuntimeError.hxx>
#include <cosmos/io/EventFile.hxx>
#include <cosmos/utils.hxx>
 
namespace cosmos {
 
EventFile::EventFile(const Counter initval, const Flags flags) {
        auto fd = ::eventfd(to_integral(initval), flags.raw());
 
        if (fd == -1) {
                cosmos_throw (ApiError("eventfd()"));
        }
 
        this->open(FileDescriptor{FileNum{fd}}, AutoCloseFD{true});
}
 
EventFile::Counter EventFile::wait() {
        Counter ret;
        // I don't believe short reads are possible with eventfds, so use
        // regular read() instead of readAll().
        const auto bytes = this->read(&ret, sizeof(Counter));
 
        if (bytes != sizeof(ret)) {
                cosmos_throw (RuntimeError("short eventfd read?!"));
        }
 
        return ret;
}
 
void EventFile::signal(const Counter increment) {
        const auto bytes = this->write(&increment, sizeof(increment));
 
        if (bytes != sizeof(increment)) {
                cosmos_throw (RuntimeError("short eventfd write?!"));
        }
}
 
} // end ns