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47e540df8f
From within the timer callbacks. Recursive is problematic for several reasons. They should still work, but this way the examples and the documentation becomes simpler. I don't think we need to encourage recursive calls. Discussed in #3537 Closes #3601
458 lines
12 KiB
C
458 lines
12 KiB
C
/***************************************************************************
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* _ _ ____ _
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* Project ___| | | | _ \| |
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* / __| | | | |_) | |
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* | (__| |_| | _ <| |___
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* \___|\___/|_| \_\_____|
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*
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* Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
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*
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* This software is licensed as described in the file COPYING, which
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* you should have received as part of this distribution. The terms
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* are also available at https://curl.haxx.se/docs/copyright.html.
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*
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* You may opt to use, copy, modify, merge, publish, distribute and/or sell
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* copies of the Software, and permit persons to whom the Software is
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* furnished to do so, under the terms of the COPYING file.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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***************************************************************************/
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/* <DESC>
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* multi socket API usage with libevent 2
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* </DESC>
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*/
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/* Example application source code using the multi socket interface to
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download many files at once.
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Written by Jeff Pohlmeyer
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Requires libevent version 2 and a (POSIX?) system that has mkfifo().
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This is an adaptation of libcurl's "hipev.c" and libevent's "event-test.c"
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sample programs.
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When running, the program creates the named pipe "hiper.fifo"
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Whenever there is input into the fifo, the program reads the input as a list
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of URL's and creates some new easy handles to fetch each URL via the
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curl_multi "hiper" API.
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Thus, you can try a single URL:
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% echo http://www.yahoo.com > hiper.fifo
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Or a whole bunch of them:
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% cat my-url-list > hiper.fifo
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The fifo buffer is handled almost instantly, so you can even add more URL's
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while the previous requests are still being downloaded.
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Note:
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For the sake of simplicity, URL length is limited to 1023 char's !
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This is purely a demo app, all retrieved data is simply discarded by the write
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callback.
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*/
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <sys/time.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/poll.h>
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#include <curl/curl.h>
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#include <event2/event.h>
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#include <event2/event_struct.h>
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#include <fcntl.h>
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#include <sys/stat.h>
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#include <errno.h>
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#include <sys/cdefs.h>
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#ifdef __GNUC__
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#define _Unused __attribute__((unused))
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#else
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#define _Unused
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#endif
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#define MSG_OUT stdout /* Send info to stdout, change to stderr if you want */
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/* Global information, common to all connections */
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typedef struct _GlobalInfo
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{
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struct event_base *evbase;
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struct event fifo_event;
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struct event timer_event;
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CURLM *multi;
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int still_running;
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FILE *input;
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int stopped;
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} GlobalInfo;
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/* Information associated with a specific easy handle */
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typedef struct _ConnInfo
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{
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CURL *easy;
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char *url;
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GlobalInfo *global;
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char error[CURL_ERROR_SIZE];
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} ConnInfo;
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/* Information associated with a specific socket */
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typedef struct _SockInfo
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{
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curl_socket_t sockfd;
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CURL *easy;
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int action;
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long timeout;
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struct event ev;
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GlobalInfo *global;
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} SockInfo;
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#define __case(code) \
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case code: s = __STRING(code)
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/* Die if we get a bad CURLMcode somewhere */
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static void mcode_or_die(const char *where, CURLMcode code)
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{
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if(CURLM_OK != code) {
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const char *s;
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switch(code) {
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__case(CURLM_BAD_HANDLE); break;
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__case(CURLM_BAD_EASY_HANDLE); break;
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__case(CURLM_OUT_OF_MEMORY); break;
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__case(CURLM_INTERNAL_ERROR); break;
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__case(CURLM_UNKNOWN_OPTION); break;
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__case(CURLM_LAST); break;
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default: s = "CURLM_unknown"; break;
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__case(CURLM_BAD_SOCKET);
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fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
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/* ignore this error */
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return;
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}
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fprintf(MSG_OUT, "ERROR: %s returns %s\n", where, s);
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exit(code);
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}
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}
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/* Update the event timer after curl_multi library calls */
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static int multi_timer_cb(CURLM *multi _Unused, long timeout_ms, GlobalInfo *g)
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{
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struct timeval timeout;
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CURLMcode rc;
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timeout.tv_sec = timeout_ms/1000;
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timeout.tv_usec = (timeout_ms%1000)*1000;
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fprintf(MSG_OUT, "multi_timer_cb: Setting timeout to %ld ms\n", timeout_ms);
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/*
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* if timeout_ms is -1, just delete the timer
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*
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* For all other values of timeout_ms, this should set or *update* the timer
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* to the new value
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*/
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if(timeout_ms == -1)
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evtimer_del(&g->timer_event);
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else /* includes timeout zero */
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evtimer_add(&g->timer_event, &timeout);
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return 0;
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}
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/* Check for completed transfers, and remove their easy handles */
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static void check_multi_info(GlobalInfo *g)
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{
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char *eff_url;
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CURLMsg *msg;
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int msgs_left;
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ConnInfo *conn;
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CURL *easy;
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CURLcode res;
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fprintf(MSG_OUT, "REMAINING: %d\n", g->still_running);
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while((msg = curl_multi_info_read(g->multi, &msgs_left))) {
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if(msg->msg == CURLMSG_DONE) {
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easy = msg->easy_handle;
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res = msg->data.result;
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curl_easy_getinfo(easy, CURLINFO_PRIVATE, &conn);
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curl_easy_getinfo(easy, CURLINFO_EFFECTIVE_URL, &eff_url);
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fprintf(MSG_OUT, "DONE: %s => (%d) %s\n", eff_url, res, conn->error);
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curl_multi_remove_handle(g->multi, easy);
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free(conn->url);
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curl_easy_cleanup(easy);
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free(conn);
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}
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}
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if(g->still_running == 0 && g->stopped)
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event_base_loopbreak(g->evbase);
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}
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/* Called by libevent when we get action on a multi socket */
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static void event_cb(int fd, short kind, void *userp)
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{
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GlobalInfo *g = (GlobalInfo*) userp;
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CURLMcode rc;
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int action =
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(kind & EV_READ ? CURL_CSELECT_IN : 0) |
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(kind & EV_WRITE ? CURL_CSELECT_OUT : 0);
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rc = curl_multi_socket_action(g->multi, fd, action, &g->still_running);
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mcode_or_die("event_cb: curl_multi_socket_action", rc);
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check_multi_info(g);
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if(g->still_running <= 0) {
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fprintf(MSG_OUT, "last transfer done, kill timeout\n");
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if(evtimer_pending(&g->timer_event, NULL)) {
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evtimer_del(&g->timer_event);
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}
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}
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}
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/* Called by libevent when our timeout expires */
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static void timer_cb(int fd _Unused, short kind _Unused, void *userp)
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{
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GlobalInfo *g = (GlobalInfo *)userp;
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CURLMcode rc;
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rc = curl_multi_socket_action(g->multi,
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CURL_SOCKET_TIMEOUT, 0, &g->still_running);
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mcode_or_die("timer_cb: curl_multi_socket_action", rc);
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check_multi_info(g);
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}
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/* Clean up the SockInfo structure */
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static void remsock(SockInfo *f)
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{
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if(f) {
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event_del(&f->ev);
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free(f);
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}
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}
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/* Assign information to a SockInfo structure */
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static void setsock(SockInfo *f, curl_socket_t s, CURL *e, int act,
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GlobalInfo *g)
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{
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int kind =
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(act&CURL_POLL_IN?EV_READ:0)|(act&CURL_POLL_OUT?EV_WRITE:0)|EV_PERSIST;
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f->sockfd = s;
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f->action = act;
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f->easy = e;
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event_del(&f->ev);
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event_assign(&f->ev, g->evbase, f->sockfd, kind, event_cb, g);
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event_add(&f->ev, NULL);
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}
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/* Initialize a new SockInfo structure */
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static void addsock(curl_socket_t s, CURL *easy, int action, GlobalInfo *g)
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{
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SockInfo *fdp = calloc(sizeof(SockInfo), 1);
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fdp->global = g;
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setsock(fdp, s, easy, action, g);
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curl_multi_assign(g->multi, s, fdp);
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}
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/* CURLMOPT_SOCKETFUNCTION */
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static int sock_cb(CURL *e, curl_socket_t s, int what, void *cbp, void *sockp)
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{
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GlobalInfo *g = (GlobalInfo*) cbp;
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SockInfo *fdp = (SockInfo*) sockp;
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const char *whatstr[]={ "none", "IN", "OUT", "INOUT", "REMOVE" };
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fprintf(MSG_OUT,
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"socket callback: s=%d e=%p what=%s ", s, e, whatstr[what]);
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if(what == CURL_POLL_REMOVE) {
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fprintf(MSG_OUT, "\n");
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remsock(fdp);
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}
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else {
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if(!fdp) {
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fprintf(MSG_OUT, "Adding data: %s\n", whatstr[what]);
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addsock(s, e, what, g);
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}
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else {
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fprintf(MSG_OUT,
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"Changing action from %s to %s\n",
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whatstr[fdp->action], whatstr[what]);
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setsock(fdp, s, e, what, g);
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}
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}
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return 0;
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}
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/* CURLOPT_WRITEFUNCTION */
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static size_t write_cb(void *ptr _Unused, size_t size, size_t nmemb,
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void *data)
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{
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size_t realsize = size * nmemb;
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ConnInfo *conn _Unused = (ConnInfo*) data;
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return realsize;
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}
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/* CURLOPT_PROGRESSFUNCTION */
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static int prog_cb(void *p, double dltotal, double dlnow, double ult _Unused,
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double uln _Unused)
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{
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ConnInfo *conn = (ConnInfo *)p;
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fprintf(MSG_OUT, "Progress: %s (%g/%g)\n", conn->url, dlnow, dltotal);
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return 0;
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}
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/* Create a new easy handle, and add it to the global curl_multi */
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static void new_conn(char *url, GlobalInfo *g)
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{
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ConnInfo *conn;
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CURLMcode rc;
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conn = calloc(1, sizeof(ConnInfo));
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conn->error[0]='\0';
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conn->easy = curl_easy_init();
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if(!conn->easy) {
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fprintf(MSG_OUT, "curl_easy_init() failed, exiting!\n");
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exit(2);
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}
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conn->global = g;
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conn->url = strdup(url);
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curl_easy_setopt(conn->easy, CURLOPT_URL, conn->url);
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curl_easy_setopt(conn->easy, CURLOPT_WRITEFUNCTION, write_cb);
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curl_easy_setopt(conn->easy, CURLOPT_WRITEDATA, conn);
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curl_easy_setopt(conn->easy, CURLOPT_VERBOSE, 1L);
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curl_easy_setopt(conn->easy, CURLOPT_ERRORBUFFER, conn->error);
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curl_easy_setopt(conn->easy, CURLOPT_PRIVATE, conn);
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curl_easy_setopt(conn->easy, CURLOPT_NOPROGRESS, 0L);
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curl_easy_setopt(conn->easy, CURLOPT_PROGRESSFUNCTION, prog_cb);
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curl_easy_setopt(conn->easy, CURLOPT_PROGRESSDATA, conn);
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curl_easy_setopt(conn->easy, CURLOPT_FOLLOWLOCATION, 1L);
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fprintf(MSG_OUT,
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"Adding easy %p to multi %p (%s)\n", conn->easy, g->multi, url);
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rc = curl_multi_add_handle(g->multi, conn->easy);
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mcode_or_die("new_conn: curl_multi_add_handle", rc);
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/* note that the add_handle() will set a time-out to trigger very soon so
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that the necessary socket_action() call will be called by this app */
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}
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/* This gets called whenever data is received from the fifo */
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static void fifo_cb(int fd _Unused, short event _Unused, void *arg)
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{
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char s[1024];
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long int rv = 0;
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int n = 0;
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GlobalInfo *g = (GlobalInfo *)arg;
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do {
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s[0]='\0';
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rv = fscanf(g->input, "%1023s%n", s, &n);
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s[n]='\0';
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if(n && s[0]) {
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if(!strcmp(s, "stop")) {
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g->stopped = 1;
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if(g->still_running == 0)
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event_base_loopbreak(g->evbase);
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}
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else
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new_conn(s, arg); /* if we read a URL, go get it! */
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}
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else
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break;
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} while(rv != EOF);
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}
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/* Create a named pipe and tell libevent to monitor it */
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static const char *fifo = "hiper.fifo";
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static int init_fifo(GlobalInfo *g)
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{
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struct stat st;
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curl_socket_t sockfd;
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fprintf(MSG_OUT, "Creating named pipe \"%s\"\n", fifo);
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if(lstat (fifo, &st) == 0) {
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if((st.st_mode & S_IFMT) == S_IFREG) {
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errno = EEXIST;
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perror("lstat");
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exit(1);
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}
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}
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unlink(fifo);
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if(mkfifo (fifo, 0600) == -1) {
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perror("mkfifo");
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exit(1);
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}
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sockfd = open(fifo, O_RDWR | O_NONBLOCK, 0);
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if(sockfd == -1) {
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perror("open");
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exit(1);
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}
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g->input = fdopen(sockfd, "r");
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fprintf(MSG_OUT, "Now, pipe some URL's into > %s\n", fifo);
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event_assign(&g->fifo_event, g->evbase, sockfd, EV_READ|EV_PERSIST,
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fifo_cb, g);
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event_add(&g->fifo_event, NULL);
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return (0);
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}
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static void clean_fifo(GlobalInfo *g)
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{
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event_del(&g->fifo_event);
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fclose(g->input);
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unlink(fifo);
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}
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int main(int argc _Unused, char **argv _Unused)
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{
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GlobalInfo g;
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memset(&g, 0, sizeof(GlobalInfo));
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g.evbase = event_base_new();
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init_fifo(&g);
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g.multi = curl_multi_init();
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evtimer_assign(&g.timer_event, g.evbase, timer_cb, &g);
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/* setup the generic multi interface options we want */
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curl_multi_setopt(g.multi, CURLMOPT_SOCKETFUNCTION, sock_cb);
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curl_multi_setopt(g.multi, CURLMOPT_SOCKETDATA, &g);
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curl_multi_setopt(g.multi, CURLMOPT_TIMERFUNCTION, multi_timer_cb);
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curl_multi_setopt(g.multi, CURLMOPT_TIMERDATA, &g);
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/* we don't call any curl_multi_socket*() function yet as we have no handles
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added! */
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event_base_dispatch(g.evbase);
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/* this, of course, won't get called since only way to stop this program is
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via ctrl-C, but it is here to show how cleanup /would/ be done. */
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clean_fifo(&g);
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event_del(&g.timer_event);
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event_base_free(g.evbase);
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curl_multi_cleanup(g.multi);
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return 0;
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}
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