platform_timer_posix.cpp

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#include <sysio/chain/platform_timer.hpp>
#include <sysio/chain/platform_timer_accuracy.hpp>
 
#include <fc/time.hpp>
#include <fc/fwd_impl.hpp>
#include <fc/exception/exception.hpp>
 
#include <mutex>
 
#include <signal.h>
#include <time.h>
 
namespace sysio { namespace chain {
 
static_assert(std::atomic_bool::is_always_lock_free, "Only lock-free atomics AS-safe.");
 
struct platform_timer::impl {
   timer_t timerid;
 
   static void sig_handler(int, siginfo_t* si, void*) {
      platform_timer* self = (platform_timer*)si->si_value.sival_ptr;
      self->expired = 1;
      self->call_expiration_callback();
   }
};
 
platform_timer::platform_timer() {
   static_assert(sizeof(impl) <= fwd_size);
 
   static bool initialized;
   static std::mutex initalized_mutex;
 
   if(std::lock_guard guard(initalized_mutex); !initialized) {
      struct sigaction act;
      sigemptyset(&act.sa_mask);
      act.sa_sigaction = impl::sig_handler;
      act.sa_flags = SA_SIGINFO | SA_RESTART;
      FC_ASSERT(sigaction(SIGRTMIN, &act, NULL) == 0, "failed to aquire SIGRTMIN signal");
      initialized = true;
   }
 
   struct sigevent se;
   se.sigev_notify = SIGEV_SIGNAL;
   se.sigev_signo = SIGRTMIN;
   se.sigev_value.sival_ptr = (void*)this;
 
   FC_ASSERT(timer_create(CLOCK_REALTIME, &se, &my->timerid) == 0, "failed to create timer");
 
   compute_and_print_timer_accuracy(*this);
}
 
platform_timer::~platform_timer() {
   timer_delete(my->timerid);
}
 
void platform_timer::start(fc::time_point tp) {
   if(tp == fc::time_point::maximum()) {
      expired = 0;
      return;
   }
   fc::microseconds x = tp.time_since_epoch() - fc::time_point::now().time_since_epoch();
   if(x.count() <= 0)
      expired = 1;
   else {
      time_t secs = x.count() / 1000000;
      long nsec = (x.count() - (secs*1000000)) * 1000;
      struct itimerspec enable = {{0, 0}, {secs, nsec}};
      expired = 0;
      if(timer_settime(my->timerid, 0, &enable, NULL) != 0)
         expired = 1;
   }
}
 
void platform_timer::stop() {
   if(expired)
      return;
   struct itimerspec disable = {{0, 0}, {0, 0}};
   timer_settime(my->timerid, 0, &disable, NULL);
   expired = 1;
}
 
}}