conet/aux.h

/***********************************************
        File Name: aux.h
        Author: Abby Cin
        Mail: abbytsing@gmail.com
        Created Time: 10/24/20 2:43 PM
***********************************************/

#ifndef _CONET_AUX_H_
#define _CONET_AUX_H_

#include <sys/socket.h>
#include <sys/epoll.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>
#include <thread>
#include <mutex>
#include <string>
#include <coroutine>
#include <vector>
#include <map>
#include <iostream>

struct debugger
{
  debugger(const char* s, int n) { std::cout << s << ':' << n << " => "; }
  template<typename... Args>
  void print(Args&&... args)
  {
    ((std::cout << args << ' '), ...);
    std::cout << '\n';
  }
};

#define debug(...) debugger(__func__, __LINE__).print(__VA_ARGS__)

using handle_t = std::coroutine_handle<>;

class acceptor;
class resolver
{
  friend acceptor;
  int fd_{0};
  explicit resolver(int fd) : fd_{fd} {}

public:
  static resolver from_str(std::string s)
  {
    struct addrinfo hints
    {
    };
    ::memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = 0;
    struct addrinfo* addrs;

    auto sep = s.find(':');
    if(sep == std::string::npos)
    {
      throw std::runtime_error("invalid address");
    }
    auto port = s.substr(sep + 1);
    auto domain = s.substr(0, sep);
    if(port.empty() || domain.empty())
    {
      throw std::runtime_error("invalid address");
    }

    int r = ::getaddrinfo(domain.data(), port.data(), &hints, &addrs);
    if(r < 0)
    {
      throw std::runtime_error(::gai_strerror(r));
    }
    int fd = 0;
    for(auto p = addrs; p != nullptr; p = p->ai_next)
    {
      fd = ::socket(p->ai_family, p->ai_socktype, p->ai_protocol);
      if(fd == -1)
      {
        continue;
      }

      if(::bind(fd, p->ai_addr, p->ai_addrlen) == 0)
      {
        break;
      }
      ::close(fd);
    }
    ::freeaddrinfo(addrs);
    if(fd == 0)
    {
      throw std::runtime_error("can't bind to any interface");
    }
    return resolver{fd};
  }
};

#endif //_CONET_AUX_H_