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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.
79 lines
2.4 KiB
C
79 lines
2.4 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 <time.h>
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#include "ares.h"
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#include "ares_private.h"
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/* WARNING: Beware that this is linear in the number of outstanding
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* requests! You are probably far better off just calling ares_process()
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* once per second, rather than calling ares_timeout() to figure out
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* when to next call ares_process().
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*/
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struct timeval *ares_timeout(ares_channel channel, struct timeval *maxtv,
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struct timeval *tvbuf)
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{
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struct query *query;
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struct list_node* list_head;
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struct list_node* list_node;
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time_t now;
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time_t offset, min_offset; /* these use time_t since some 32 bit systems
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still use 64 bit time_t! (like VS2005) */
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/* No queries, no timeout (and no fetch of the current time). */
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if (ares__is_list_empty(&(channel->all_queries)))
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return maxtv;
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/* Find the minimum timeout for the current set of queries. */
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time(&now);
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min_offset = -1;
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list_head = &(channel->all_queries);
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for (list_node = list_head->next; list_node != list_head;
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list_node = list_node->next)
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{
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query = list_node->data;
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if (query->timeout == 0)
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continue;
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offset = query->timeout - now;
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if (offset < 0)
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offset = 0;
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if (min_offset == -1 || offset < min_offset)
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min_offset = offset;
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}
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/* If we found a minimum timeout and it's sooner than the one
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* specified in maxtv (if any), return it. Otherwise go with
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* maxtv.
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*/
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if (min_offset != -1 && (!maxtv || min_offset <= maxtv->tv_sec))
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{
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tvbuf->tv_sec = (long)min_offset;
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tvbuf->tv_usec = 0;
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return tvbuf;
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}
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else
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return maxtv;
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}
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