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3rdparty/c-ares-1.18.1/src/lib/ares_getsock.c 2.25 KB
73ef4ff3   Hu Chunming   提交三方库
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  /* Copyright (C) 2005 - 2010, Daniel Stenberg
   *
   * Permission to use, copy, modify, and distribute this software and its
   * documentation for any purpose and without fee is hereby granted, provided
   * that the above copyright notice appear in all copies and that both that
   * copyright notice and this permission notice appear in supporting
   * documentation, and that the name of M.I.T. not be used in advertising or
   * publicity pertaining to distribution of the software without specific,
   * written prior permission.  M.I.T. makes no representations about the
   * suitability of this software for any purpose.  It is provided "as is"
   * without express or implied warranty.
   */
  
  #include "ares_setup.h"
  
  #include "ares.h"
  #include "ares_private.h"
  
  int ares_getsock(ares_channel channel,
                   ares_socket_t *socks,
                   int numsocks) /* size of the 'socks' array */
  {
    struct server_state *server;
    int i;
    int sockindex=0;
    int bitmap = 0;
    unsigned int setbits = 0xffffffff;
  
    /* Are there any active queries? */
    int active_queries = !ares__is_list_empty(&(channel->all_queries));
  
    for (i = 0; i < channel->nservers; i++)
      {
        server = &channel->servers[i];
        /* We only need to register interest in UDP sockets if we have
         * outstanding queries.
         */
        if (active_queries && server->udp_socket != ARES_SOCKET_BAD)
          {
            if(sockindex >= numsocks || sockindex >= ARES_GETSOCK_MAXNUM)
              break;
            socks[sockindex] = server->udp_socket;
            bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex);
            sockindex++;
          }
        /* We always register for TCP events, because we want to know
         * when the other side closes the connection, so we don't waste
         * time trying to use a broken connection.
         */
        if (server->tcp_socket != ARES_SOCKET_BAD)
         {
           if(sockindex >= numsocks || sockindex >= ARES_GETSOCK_MAXNUM)
             break;
           socks[sockindex] = server->tcp_socket;
           bitmap |= ARES_GETSOCK_READABLE(setbits, sockindex);
  
           if (server->qhead && active_queries)
             /* then the tcp socket is also writable! */
             bitmap |= ARES_GETSOCK_WRITABLE(setbits, sockindex);
  
           sockindex++;
         }
      }
    return bitmap;
  }