rec: mention rust compiler in compiling docs

[thirdparty/pdns.git] / pdns / pollmplexer.cc

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "mplexer.hh"
#include "sstuff.hh"
#include <iostream>
#include <poll.h>
#include <unordered_map>
#include "misc.hh"
#include "namespaces.hh"

FDMultiplexer* FDMultiplexer::getMultiplexerSilent(unsigned int maxEventsHint)
{
  FDMultiplexer* ret = nullptr;
  for (const auto& i : FDMultiplexer::getMultiplexerMap()) {
    try {
      ret = i.second(std::min(maxEventsHint, FDMultiplexer::s_maxevents));
      return ret;
    }
    catch (const FDMultiplexerException& fe) {
    }
    catch (...) {
    }
  }
  return ret;
}

class PollFDMultiplexer : public FDMultiplexer
{
public:
  PollFDMultiplexer(unsigned int /* maxEventsHint */)
  {}

  int run(struct timeval* tv, int timeout = 500) override;
  void getAvailableFDs(std::vector<int>& fds, int timeout) override;

  void addFD(int fd, FDMultiplexer::EventKind) override;
  void removeFD(int fd, FDMultiplexer::EventKind) override;

  string getName() const override
  {
    return "poll";
  }

private:
  std::unordered_map<int, struct pollfd> d_pollfds;
  vector<struct pollfd> preparePollFD() const;
};

static FDMultiplexer* make(unsigned int maxEventsHint)
{
  return new PollFDMultiplexer(maxEventsHint);
}

static struct RegisterOurselves
{
  RegisterOurselves()
  {
    FDMultiplexer::getMultiplexerMap().emplace(2, &make);
  }
} doIt;

static int convertEventKind(FDMultiplexer::EventKind kind)
{
  switch (kind) {
  case FDMultiplexer::EventKind::Read:
    return POLLIN;
  case FDMultiplexer::EventKind::Write:
    return POLLOUT;
  case FDMultiplexer::EventKind::Both:
    return POLLIN | POLLOUT;
  }
  throw std::runtime_error("Unhandled event kind in the ports multiplexer");
}

void PollFDMultiplexer::addFD(int fd, FDMultiplexer::EventKind kind)
{
  if (d_pollfds.count(fd) == 0) {
    auto& pollfd = d_pollfds[fd];
    pollfd.fd = fd;
    pollfd.events = 0;
  }
  auto& pollfd = d_pollfds.at(fd);
  pollfd.events |= convertEventKind(kind);
}

void PollFDMultiplexer::removeFD(int fd, FDMultiplexer::EventKind)
{
  d_pollfds.erase(fd);
}

vector<struct pollfd> PollFDMultiplexer::preparePollFD() const
{
  std::vector<struct pollfd> result;
  result.reserve(d_pollfds.size());
  for (const auto& entry : d_pollfds) {
    result.push_back(entry.second);
  }

  return result;
}

void PollFDMultiplexer::getAvailableFDs(std::vector<int>& fds, int timeout)
{
  auto pollfds = preparePollFD();
  if (pollfds.empty()) {
    return;
  }

  int ret = poll(&pollfds[0], pollfds.size(), timeout);

  if (ret < 0 && errno != EINTR) {
    throw FDMultiplexerException("poll returned error: " + stringerror());
  }

  for (const auto& pollfd : pollfds) {
    if (pollfd.revents & POLLIN || pollfd.revents & POLLOUT || pollfd.revents & POLLERR || pollfd.revents & POLLHUP) {
      fds.push_back(pollfd.fd);
    }
  }
}

int PollFDMultiplexer::run(struct timeval* now, int timeout)
{
  if (d_inrun) {
    throw FDMultiplexerException("FDMultiplexer::run() is not reentrant!\n");
  }

  auto pollfds = preparePollFD();
  if (pollfds.empty()) {
    gettimeofday(now, nullptr); // MANDATORY!
    return 0;
  }

  int ret = poll(&pollfds[0], pollfds.size(), timeout);
  gettimeofday(now, nullptr); // MANDATORY!

  if (ret < 0 && errno != EINTR) {
    throw FDMultiplexerException("poll returned error: " + stringerror());
  }

  d_inrun = true;
  int count = 0;
  for (const auto& pollfd : pollfds) {
    if (pollfd.revents & POLLIN || pollfd.revents & POLLERR || pollfd.revents & POLLHUP) {
      const auto& iter = d_readCallbacks.find(pollfd.fd);
      if (iter != d_readCallbacks.end()) {
        iter->d_callback(iter->d_fd, iter->d_parameter);
        count++;
      }
    }

    if (pollfd.revents & POLLOUT || pollfd.revents & POLLERR) {
      const auto& iter = d_writeCallbacks.find(pollfd.fd);
      if (iter != d_writeCallbacks.end()) {
        iter->d_callback(iter->d_fd, iter->d_parameter);
        count++;
      }
    }
  }

  d_inrun = false;
  return count;
}

#if 0

void acceptData(int fd, boost::any& parameter)
{
  cout<<"Have data on fd "<<fd<<endl;
  Socket* sock=boost::any_cast<Socket*>(parameter);
  string packet;
  IPEndpoint rem;
  sock->recvFrom(packet, rem);
  cout<<"Received "<<packet.size()<<" bytes!\n";
}


int main()
{
  Socket s(AF_INET, SOCK_DGRAM);

  IPEndpoint loc("0.0.0.0", 2000);
  s.bind(loc);

  PollFDMultiplexer sfm;

  sfm.addReadFD(s.getHandle(), &acceptData, &s);

  for(int n=0; n < 100 ; ++n) {
    sfm.run();
  }
  sfm.removeReadFD(s.getHandle());
  sfm.removeReadFD(s.getHandle());
}
#endif