~singpolyma/biboumi

7869ef2ace9a487abb0b489ca432b0a8878c5083 — Florent Le Coz 9 years ago
First step of the connection skeleton

Basic connect, socket creating, polling, recving, etc.
A  => src/libirc/irc_client.cpp +102 -0
@@ 1,102 @@
#include <libirc/irc_client.hpp>
#include <network/poller.hpp>
#include <utils/scopeguard.hpp>

#include <sys/types.h>
#include <sys/socket.h>
#include <cstring>
#include <netdb.h>
#include <unistd.h>

#include <iostream>
#include <stdexcept>

IrcClient::IrcClient()
{
  std::cout << "IrcClient()" << std::endl;
  if ((this->socket = ::socket(AF_INET, SOCK_STREAM, 0)) == -1)
    throw std::runtime_error("Could not create socket");
}

IrcClient::~IrcClient()
{
  std::cout << "~IrcClient()" << std::endl;
}

void IrcClient::on_recv()
{
  char buf[4096];

  ssize_t size = ::recv(this->socket, buf, 4096, 0);
  if (0 == size)
    this->on_connection_close();
  else if (-1 == static_cast<ssize_t>(size))
    throw std::runtime_error("Error reading from socket");
  else
    {
      this->in_buf += std::string(buf, size);
      this->parse_in_buffer();
    }
}

void IrcClient::on_send()
{
}

socket_t IrcClient::get_socket() const
{
  return this->socket;
}

void IrcClient::connect(const std::string& address, const std::string& port)
{
  std::cout << "Trying to connect to " << address << ":" << port << std::endl;
  struct addrinfo hints;
  memset(&hints, 0, sizeof(struct addrinfo));
  hints.ai_flags = 0;
  hints.ai_family = AF_INET;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_protocol = 0;

  struct addrinfo* addr_res;
  const int res = ::getaddrinfo(address.c_str(), port.c_str(), &hints, &addr_res);
  // Make sure the alloced structure is always freed at the end of the
  // function
  utils::ScopeGuard sg([&addr_res](){ freeaddrinfo(addr_res); });

  if (res != 0)
    {
      perror("getaddrinfo");
      throw std::runtime_error("getaddrinfo failed");
    }
  for (struct addrinfo* rp = addr_res; rp; rp = rp->ai_next)
    {
      std::cout << "One result" << std::endl;
      if (::connect(this->socket, rp->ai_addr, rp->ai_addrlen) == 0)
        {
          std::cout << "Connection success." << std::endl;
          return ;
        }
      std::cout << "Connection failed:" << std::endl;
      perror("connect");
    }
  std::cout << "All connection attempts failed." << std::endl;
  this->close();
}

void IrcClient::on_connection_close()
{
  std::cout << "Connection closed by remote server." << std::endl;
  this->close();
}

void IrcClient::close()
{
  this->poller->remove_socket_handler(this->get_socket());
  ::close(this->socket);
}

void IrcClient::parse_in_buffer()
{
  std::cout << "Parsing: [" << this->in_buf << "]" << std::endl;
}

A  => src/libirc/irc_client.hpp +67 -0
@@ 1,67 @@
#ifndef IRC_CLIENT_INCLUDED
# define IRC_CLIENT_INCLUDED

#include <network/socket_handler.hpp>

#include <string>

/**
 * Represent one IRC client, i.e. an endpoint connected to a single IRC
 * server, through a TCP socket, receiving and sending commands to it.
 *
 * TODO: TLS support, maybe, but that's not high priority
 */
class IrcClient: public SocketHandler
{
public:
  explicit IrcClient();
  ~IrcClient();
  /**
   * We read the data, try to parse it and generate some event if
   * one or more full message is available.
   */
  void on_recv();
  /**
   * Just write as much data as possible on the socket.
   */
  void on_send();
  socket_t get_socket() const;
  /**
   * Connect to the remote server
   */
  void connect(const std::string& address, const std::string& port);
  /**
   * Close the connection, remove us from the poller
   */
  void close();
  /**
   * Called when we detect an orderly close by the remote endpoint.
   */
  void on_connection_close();
  /**
   * Parse the data we have received so far and try to get one or more
   * complete messages from it.
   */
  void parse_in_buffer();

private:
  socket_t socket;
  /**
   * Where data read from the socket is added, until we can parse a whole
   * IRC message, the used data is then removed from that buffer.
   *
   * TODO: something more efficient than a string.
   */
  std::string in_buf;
  /**
   * Where data is added, when we want to send something to the client.
   */
  std::string out_buf;

  IrcClient(const IrcClient&) = delete;
  IrcClient(IrcClient&&) = delete;
  IrcClient& operator=(const IrcClient&) = delete;
  IrcClient& operator=(IrcClient&&) = delete;
};

#endif // IRC_CLIENT_INCLUDED

A  => src/network/poller.cpp +96 -0
@@ 1,96 @@
#include <network/poller.hpp>

#include <assert.h>
#include <cstring>
#include <iostream>


Poller::Poller()
{
  std::cout << "Poller()" << std::endl;
#if POLLER == POLL
  memset(this->fds, 0, sizeof(this->fds));
  this->nfds = 0;
#endif
}

Poller::~Poller()
{
  std::cout << "~Poller()" << std::endl;
}

void Poller::add_socket_handler(std::shared_ptr<SocketHandler> socket_handler)
{
  // Raise an error if that socket is already in the list
  const auto it = this->socket_handlers.find(socket_handler->get_socket());
  if (it != this->socket_handlers.end())
    throw std::runtime_error("Trying to insert SocketHandler already managed");

  this->socket_handlers.emplace(socket_handler->get_socket(), socket_handler);
  socket_handler->set_poller(this);

  // We always watch all sockets for receive events
#if POLLER == POLL
  this->fds[this->nfds].fd = socket_handler->get_socket();
  this->fds[this->nfds].events = POLLIN;
  this->nfds++;
#endif
}

void Poller::remove_socket_handler(const socket_t socket)
{
  const auto it = this->socket_handlers.find(socket);
  if (it == this->socket_handlers.end())
    throw std::runtime_error("Trying to remove a SocketHandler that is not managed");
  this->socket_handlers.erase(it);
  for (size_t i = 0; i < this->nfds; i++)
    {
      if (this->fds[i].fd == socket)
        {
          // Move all subsequent pollfd by one on the left, erasing the
          // value of the one we remove
          for (size_t j = i; j < this->nfds - 1; ++j)
            {
              this->fds[j].fd = this->fds[j+1].fd;
              this->fds[j].events= this->fds[j+1].events;
            }
          this->nfds--;
        }
    }
}

void Poller::poll()
{
#if POLLER == POLL
  std::cout << "Polling:" << std::endl;
  for (size_t i = 0; i < this->nfds; ++i)
    std::cout << "pollfd[" << i << "]: (" << this->fds[i].fd << ")" << std::endl;
  int res = ::poll(this->fds, this->nfds, -1);
  if (res < 0)
    {
      perror("poll");
      throw std::runtime_error("Poll failed");
    }
  // We cannot possibly have more ready events than the number of fds we are
  // watching
  assert(static_cast<unsigned int>(res) <= this->nfds);
  for (size_t i = 0; i <= this->nfds && res != 0; ++i)
    {
      if (this->fds[i].revents == 0)
        continue;
      else if (this->fds[i].revents & POLLIN)
        {
          auto socket_handler = this->socket_handlers.at(this->fds[i].fd);
          socket_handler->on_recv();
          res--;
        }
      else if (this->fds[i].revents & POLLOUT)
        {
          auto socket_handler = this->socket_handlers.at(this->fds[i].fd);
          socket_handler->on_send();
          res--;
        }
    }
#endif
}


A  => src/network/poller.hpp +72 -0
@@ 1,72 @@
#ifndef POLLER_INCLUDED
# define POLLER_INCLUDED

#include <network/socket_handler.hpp>

#include <unordered_map>
#include <memory>

#define POLL 1
#define EPOLL 2
#define KQUEUE 3

#define POLLER POLL

#if POLLER == POLL
 #include <poll.h>
 // TODO, dynamic size, without artificial limit
 #define MAX_POLL_FD_NUMBER 4096
#endif

/**
 * We pass some SocketHandlers to this the Poller, which uses
 * poll/epoll/kqueue/select etc to wait for events on these SocketHandlers,
 * and call the callbacks when event occurs.
 *
 * TODO: support for all these pollers:
 * - poll(2) (mandatory)
 * - epoll(7)
 * - kqueue(2)
 */


class Poller
{
public:
  explicit Poller();
  ~Poller();
  /**
   * Add a SocketHandler to be monitored by this Poller. All receive events
   * are always automatically watched.
   */
  void add_socket_handler(std::shared_ptr<SocketHandler> socket_handler);
  /**
   * Remove (and stop managing) a SocketHandler, designed by the given socket_t.
   */
  void remove_socket_handler(const socket_t socket);
  /**
   * Wait for all watched events, and call the SocketHandlers' callbacks
   * when one is ready.
   */
  void poll();

private:
  /**
   * A "list" of all the SocketHandlers that we manage, indexed by socket,
   * because that's what is returned by select/poll/etc when an event
   * occures.
   */
  std::unordered_map<socket_t, std::shared_ptr<SocketHandler>> socket_handlers;

#if POLLER == POLL
  struct pollfd fds[MAX_POLL_FD_NUMBER];
  nfds_t nfds;
#endif

  Poller(const Poller&) = delete;
  Poller(Poller&&) = delete;
  Poller& operator=(const Poller&) = delete;
  Poller& operator=(Poller&&) = delete;
};

#endif // POLLER_INCLUDED

A  => src/network/socket_handler.hpp +62 -0
@@ 1,62 @@
#ifndef SOCKET_HANDLER_INCLUDED
# define SOCKET_HANDLER_INCLUDED

typedef int socket_t;

class Poller;

/**
 * An interface, with a series of callbacks that should be implemented in
 * subclasses that deal with a socket. These callbacks are called on various events
 * (read/write/timeout, etc) when they are notified to a poller
 * (select/poll/epoll etc)
 */
class SocketHandler
{
public:
  explicit SocketHandler():
    poller(nullptr)
  {}
  /**
   * Set the pointer to the given Poller, to communicate with it.
   */
  void set_poller(Poller* poller)
  {
    this->poller = poller;
  };
  /**
   * Happens when the socket is ready to be received from.
   */
  virtual void on_recv() = 0;
  /**
   * Happens when the socket is ready to be written to.
   */
  virtual void on_send() = 0;
  /**
   * Returns the socket that should be handled by the poller.
   */
  virtual socket_t get_socket() const = 0;
  /**
   * Close the connection.
   */
  virtual void close() = 0;

protected:
  /**
   * A pointer to the poller that manages us, because we need to communicate
   * with it, sometimes (for example to tell it that he now needs to watch
   * write events for us). Do not ever try to delete it.
   *
   * And a raw pointer because we are not owning it, it is owning us
   * (actually it is sharing our ownership with a Bridge).
   */
  Poller* poller;

private:
  SocketHandler(const SocketHandler&) = delete;
  SocketHandler(SocketHandler&&) = delete;
  SocketHandler& operator=(const SocketHandler&) = delete;
  SocketHandler& operator=(SocketHandler&&) = delete;
};

#endif // SOCKET_HANDLER_INCLUDED

A  => src/utils/scopeguard.hpp +89 -0
@@ 1,89 @@
#ifndef SCOPEGUARD_HPP
#define SCOPEGUARD_HPP

#include <functional>
#include <vector>

/**
 * A class to be used to make sure some functions are called when the scope
 * is left, because they will be called in the ScopeGuard's destructor.  It
 * can for example be used to delete some pointer whenever any exception is
 * called.  Example:

 * {
 *  ScopeGuard scope;
 *  int* number = new int(2);
 *  scope.add_callback([number]() { delete number; });
 *  // Do some other stuff with the number. But these stuff might throw an exception:
 *  throw std::runtime_error("Some error not caught here, but in our caller");
 *  return true;
 * }

 * In this example, our pointer will always be deleted, even when the
 * exception is thrown.  If we want the functions to be called only when the
 * scope is left because of an unexpected exception, we can use
 * ScopeGuard::disable();
 */

namespace utils
{

class ScopeGuard
{
public:
  /**
   * The constructor can take a callback. But additional callbacks can be
   * added later with add_callback()
   */
  explicit ScopeGuard(std::function<void()>&& func):
    enabled(true)
  {
    this->add_callback(std::move(func));
  }
  /**
   * default constructor, the scope guard is enabled but empty, use
   * add_callback()
   */
  explicit ScopeGuard():
    enabled(true)
  {
  }
  /**
   * Call all callbacks in the desctructor, unless it has been disabled.
   */
  ~ScopeGuard()
  {
    if (this->enabled)
      for (auto& func: this->callbacks)
        func();
  }
  /**
   * Add a callback to be called in our destructor, one scope guard can be
   * used for more than one task, if needed.
   */
  void add_callback(std::function<void()>&& func)
  {
    this->callbacks.emplace_back(std::move(func));
  }
  /**
   * Disable that scope guard, nothing will be done when the scope is
   * exited.
   */
  void disable()
  {
    this->enabled = false;
  }

private:
  bool enabled;
  std::vector<std::function<void()>> callbacks;

  ScopeGuard(const ScopeGuard&) = delete;
  ScopeGuard& operator=(ScopeGuard&&) = delete;
  ScopeGuard(ScopeGuard&&) = delete;
  ScopeGuard& operator=(const ScopeGuard&) = delete;
};

}

#endif