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https://github.com/moparisthebest/curl
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23f5d145ec
outstanding queries, and processing a DNS response packet was O(n) in the number of outstanding queries. To speed things up in Google, we added a few circular, doubly-linked lists of queries that are hash-bucketed based on the attributes we care about, so most important operations are now O(1). It might be that the number of buckets are higher than most people would need, but on a quick calculation it should only be 100kB or so even on a 64-bit system, so I've let it stay as-is.
64 lines
2.0 KiB
C
64 lines
2.0 KiB
C
/* $Id$ */
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/* Copyright 1998 by the Massachusetts Institute of Technology.
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*
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* Permission to use, copy, modify, and distribute this
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* software and its documentation for any purpose and without
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* fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright
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* notice and this permission notice appear in supporting
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* documentation, and that the name of M.I.T. not be used in
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* advertising or publicity pertaining to distribution of the
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* software without specific, written prior permission.
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* M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is"
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* without express or implied warranty.
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*/
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#include "setup.h"
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#ifdef HAVE_SYS_TIME_H
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#include <sys/time.h>
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#endif
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#include "ares.h"
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#include "ares_private.h"
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int ares_fds(ares_channel channel, fd_set *read_fds, fd_set *write_fds)
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{
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struct server_state *server;
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ares_socket_t nfds;
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int i;
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/* Are there any active queries? */
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int active_queries = !ares__is_list_empty(&(channel->all_queries));
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nfds = 0;
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for (i = 0; i < channel->nservers; i++)
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{
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server = &channel->servers[i];
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/* We only need to register interest in UDP sockets if we have
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* outstanding queries.
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*/
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if (active_queries && server->udp_socket != ARES_SOCKET_BAD)
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{
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FD_SET(server->udp_socket, read_fds);
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if (server->udp_socket >= nfds)
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nfds = server->udp_socket + 1;
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}
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/* We always register for TCP events, because we want to know
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* when the other side closes the connection, so we don't waste
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* time trying to use a broken connection.
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*/
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if (server->tcp_socket != ARES_SOCKET_BAD)
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{
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FD_SET(server->tcp_socket, read_fds);
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if (server->qhead)
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FD_SET(server->tcp_socket, write_fds);
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if (server->tcp_socket >= nfds)
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nfds = server->tcp_socket + 1;
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}
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}
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return (int)nfds;
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}
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