plugins/icq/socketmanager.c

/* -*- Mode: C; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/*
  $Id: socketmanager.c 1539 2001-03-03 12:56:25Z warmenhoven $
*/

#include "socketmanager.h"

/**
 * The icqlib socket manager is a simple socket abstraction layer, which
 * supports opening and closing sockets as well as installing handler
 * functions for read ready and write ready events.  Its purpose is to
 * both unify socket handling in icqlib and expose icqlib's socket
 * requirements so the library client can assist with socket housekeeping.
 *
 * Library clients have two options to support icqlib:
 *
 * 1. Periodically call icq_Main.  This will handle all select logic
 * internally.  Advantage is implementation ease, disadvantage is wasted 
 * CPU cycles because of polling and poor TCP file transfer performance.
 * 
 * 2. Install a icq_SocketNotify callback, perform your own socket
 * management, and notify icqlib using the icq_SocketReady method when
 * a socket is ready for reading or writing.  Advantage is efficiency,
 * disadvantage is extra code.
 *
 */

/* need to track:
 *   socket wants read notification
 *   socket no longer wants read notification
 *   socket wants write notification
 *   socket no longer wants write notification
 */

#include <sys/types.h>

#ifndef _WIN32
#include <unistd.h>
#include <sys/time.h>
#include <sys/socket.h>
#else
#include <winsock.h>
#endif

list *icq_SocketList = NULL;
fd_set icq_FdSets[ICQ_SOCKET_MAX];
int icq_MaxSocket;

void (*icq_SocketNotify)(int socket, int type, int status);

/**
 * Creates a new socket using the operating system's socket creation
 * facitily.
 */
int icq_SocketNew(int domain, int type, int protocol)
{
  int s = socket(domain, type, protocol);

  icq_SocketAlloc(s);

  return s;
}


/**
 * Creates a new socket by accepting a connection from a listening
 * socket.
 */
int icq_SocketAccept(int listens, struct sockaddr *addr, int *addrlen)
{
  int s = accept(listens, addr, addrlen);

  icq_SocketAlloc(s);

  return s;
}

/**
 * Creates a new icq_Socket structure, and appends it to the 
 * socketmanager's global socket list.
 */
void icq_SocketAlloc(int s)
{
  if (s != -1)
  {
    icq_Socket *psocket = (icq_Socket *)malloc(sizeof(icq_Socket));
    int i;
    psocket->socket = s;

    for (i=0; i<ICQ_SOCKET_MAX; i++)
      psocket->handlers[i] = NULL;

    list_enqueue(icq_SocketList, psocket);
  }
}  

/**
 * Closes a socket.  This function will notify the library client
 * through the icq_SocketNotify callback if the socket had an installed
 * read or write handler.
 */
int icq_SocketDelete(int socket)
{
#ifdef _WIN32
  int result = closesocket(socket);
#else
  int result = close(socket);
#endif

  if (result != -1)
  {
    icq_Socket *s = icq_FindSocket(socket);
    int i;

    /* uninstall all handlers - this will take care of notifing library
     * client */
    for (i=0; i<ICQ_SOCKET_MAX; i++)
    {
      if (s->handlers[i])
        icq_SocketSetHandler(s->socket, i, NULL, NULL);
    }

    list_remove(icq_SocketList, s);
    free(s);
  }

  return result;
}

/**
 * Installs a socket event handler.  The handler will be called when
 * the socket is ready for reading or writing, depending on the type
 * which should be either ICQ_SOCKET_READ or ICQ_SOCKET_WRITE.  In 
 * addition, user data can be passed to the callback function through
 * the data member.
 */
void icq_SocketSetHandler(int socket, int type, icq_SocketHandler handler, 
  void *data)
{
  icq_Socket *s = icq_FindSocket(socket);
  if (s)
  {
    s->data[type] = data;
    s->handlers[type] = handler;
    if (icq_SocketNotify)
      (*icq_SocketNotify)(socket, type, handler ? 1 : 0);
  }
}

/**
 * Handles a socket ready event by calling the installed callback 
 * function, if any.
 */
void icq_SocketReady(icq_Socket *s, int type)
{
  if (s && s->handlers[type])
  {
    (*s->handlers[type])(s->data[type]);
  }
}

void icq_HandleReadySocket(int socket, int type)
{
  icq_SocketReady(icq_FindSocket(socket), type);
}
  
int _icq_SocketBuildFdSets(void *p, va_list data)
{
  icq_Socket *s = p;
  int i;

  for (i=0; i<ICQ_SOCKET_MAX; i++)
    if (s->handlers[i]) {
      FD_SET(s->socket, &(icq_FdSets[i]));
      if (s->socket > icq_MaxSocket)
        icq_MaxSocket = s->socket;
    }

  return 0; /* traverse entire list */
}

void icq_SocketBuildFdSets()
{
  int i;

  /* clear fdsets */
  for (i=0; i<ICQ_SOCKET_MAX; i++)
    FD_ZERO(&(icq_FdSets[i]));

  icq_MaxSocket = 0;
  
  /* build fd lists for open sockets */
  (void)list_traverse(icq_SocketList, _icq_SocketBuildFdSets);
}

int _icq_SocketHandleReady(void *p, va_list data)
{
  icq_Socket *s = p;
  int i;

  for (i=0; i<ICQ_SOCKET_MAX; i++)
    if (FD_ISSET(s->socket, &(icq_FdSets[i]))) {
      icq_SocketReady(s, i);
    }

  return 0; /* traverse entire list */
}
      
void icq_SocketPoll()
{
  struct timeval tv;
  int max_socket = 0;
  int i;

  icq_SocketBuildFdSets();
  
  tv.tv_sec = 0; tv.tv_usec = 0;
    
  /* determine which sockets require maintenance */
  select(icq_MaxSocket+1, &(icq_FdSets[ICQ_SOCKET_READ]),
    &(icq_FdSets[ICQ_SOCKET_WRITE]), NULL, &tv);

  /* handle ready sockets */
  (void)list_traverse(icq_SocketList, _icq_SocketHandleReady);
}

int _icq_FindSocket(void *p, va_list data)
{
  int socket = va_arg(data, int);
  return (((icq_Socket *)p)->socket == socket);
}

icq_Socket *icq_FindSocket(int socket)
{
  return list_traverse(icq_SocketList, _icq_FindSocket, socket);
}