Annotation of embedaddon/curl/docs/examples/multi-event.c, revision 1.1.1.1
1.1 misho 1: /***************************************************************************
2: * _ _ ____ _
3: * Project ___| | | | _ \| |
4: * / __| | | | |_) | |
5: * | (__| |_| | _ <| |___
6: * \___|\___/|_| \_\_____|
7: *
8: * Copyright (C) 1998 - 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
9: *
10: * This software is licensed as described in the file COPYING, which
11: * you should have received as part of this distribution. The terms
12: * are also available at https://curl.haxx.se/docs/copyright.html.
13: *
14: * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15: * copies of the Software, and permit persons to whom the Software is
16: * furnished to do so, under the terms of the COPYING file.
17: *
18: * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19: * KIND, either express or implied.
20: *
21: ***************************************************************************/
22:
23: /* <DESC>
24: * multi_socket API using libevent
25: * </DESC>
26: */
27:
28: #include <stdio.h>
29: #include <stdlib.h>
30: #include <event2/event.h>
31: #include <curl/curl.h>
32:
33: struct event_base *base;
34: CURLM *curl_handle;
35: struct event *timeout;
36:
37: typedef struct curl_context_s {
38: struct event *event;
39: curl_socket_t sockfd;
40: } curl_context_t;
41:
42: static void curl_perform(int fd, short event, void *arg);
43:
44: static curl_context_t* create_curl_context(curl_socket_t sockfd)
45: {
46: curl_context_t *context;
47:
48: context = (curl_context_t *) malloc(sizeof(*context));
49:
50: context->sockfd = sockfd;
51:
52: context->event = event_new(base, sockfd, 0, curl_perform, context);
53:
54: return context;
55: }
56:
57: static void destroy_curl_context(curl_context_t *context)
58: {
59: event_del(context->event);
60: event_free(context->event);
61: free(context);
62: }
63:
64: static void add_download(const char *url, int num)
65: {
66: char filename[50];
67: FILE *file;
68: CURL *handle;
69:
70: snprintf(filename, 50, "%d.download", num);
71:
72: file = fopen(filename, "wb");
73: if(!file) {
74: fprintf(stderr, "Error opening %s\n", filename);
75: return;
76: }
77:
78: handle = curl_easy_init();
79: curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
80: curl_easy_setopt(handle, CURLOPT_PRIVATE, file);
81: curl_easy_setopt(handle, CURLOPT_URL, url);
82: curl_multi_add_handle(curl_handle, handle);
83: fprintf(stderr, "Added download %s -> %s\n", url, filename);
84: }
85:
86: static void check_multi_info(void)
87: {
88: char *done_url;
89: CURLMsg *message;
90: int pending;
91: CURL *easy_handle;
92: FILE *file;
93:
94: while((message = curl_multi_info_read(curl_handle, &pending))) {
95: switch(message->msg) {
96: case CURLMSG_DONE:
97: /* Do not use message data after calling curl_multi_remove_handle() and
98: curl_easy_cleanup(). As per curl_multi_info_read() docs:
99: "WARNING: The data the returned pointer points to will not survive
100: calling curl_multi_cleanup, curl_multi_remove_handle or
101: curl_easy_cleanup." */
102: easy_handle = message->easy_handle;
103:
104: curl_easy_getinfo(easy_handle, CURLINFO_EFFECTIVE_URL, &done_url);
105: curl_easy_getinfo(easy_handle, CURLINFO_PRIVATE, &file);
106: printf("%s DONE\n", done_url);
107:
108: curl_multi_remove_handle(curl_handle, easy_handle);
109: curl_easy_cleanup(easy_handle);
110: if(file) {
111: fclose(file);
112: }
113: break;
114:
115: default:
116: fprintf(stderr, "CURLMSG default\n");
117: break;
118: }
119: }
120: }
121:
122: static void curl_perform(int fd, short event, void *arg)
123: {
124: int running_handles;
125: int flags = 0;
126: curl_context_t *context;
127:
128: if(event & EV_READ)
129: flags |= CURL_CSELECT_IN;
130: if(event & EV_WRITE)
131: flags |= CURL_CSELECT_OUT;
132:
133: context = (curl_context_t *) arg;
134:
135: curl_multi_socket_action(curl_handle, context->sockfd, flags,
136: &running_handles);
137:
138: check_multi_info();
139: }
140:
141: static void on_timeout(evutil_socket_t fd, short events, void *arg)
142: {
143: int running_handles;
144: curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0,
145: &running_handles);
146: check_multi_info();
147: }
148:
149: static int start_timeout(CURLM *multi, long timeout_ms, void *userp)
150: {
151: if(timeout_ms < 0) {
152: evtimer_del(timeout);
153: }
154: else {
155: if(timeout_ms == 0)
156: timeout_ms = 1; /* 0 means directly call socket_action, but we'll do it
157: in a bit */
158: struct timeval tv;
159: tv.tv_sec = timeout_ms / 1000;
160: tv.tv_usec = (timeout_ms % 1000) * 1000;
161: evtimer_del(timeout);
162: evtimer_add(timeout, &tv);
163: }
164: return 0;
165: }
166:
167: static int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp,
168: void *socketp)
169: {
170: curl_context_t *curl_context;
171: int events = 0;
172:
173: switch(action) {
174: case CURL_POLL_IN:
175: case CURL_POLL_OUT:
176: case CURL_POLL_INOUT:
177: curl_context = socketp ?
178: (curl_context_t *) socketp : create_curl_context(s);
179:
180: curl_multi_assign(curl_handle, s, (void *) curl_context);
181:
182: if(action != CURL_POLL_IN)
183: events |= EV_WRITE;
184: if(action != CURL_POLL_OUT)
185: events |= EV_READ;
186:
187: events |= EV_PERSIST;
188:
189: event_del(curl_context->event);
190: event_assign(curl_context->event, base, curl_context->sockfd, events,
191: curl_perform, curl_context);
192: event_add(curl_context->event, NULL);
193:
194: break;
195: case CURL_POLL_REMOVE:
196: if(socketp) {
197: event_del(((curl_context_t*) socketp)->event);
198: destroy_curl_context((curl_context_t*) socketp);
199: curl_multi_assign(curl_handle, s, NULL);
200: }
201: break;
202: default:
203: abort();
204: }
205:
206: return 0;
207: }
208:
209: int main(int argc, char **argv)
210: {
211: if(argc <= 1)
212: return 0;
213:
214: if(curl_global_init(CURL_GLOBAL_ALL)) {
215: fprintf(stderr, "Could not init curl\n");
216: return 1;
217: }
218:
219: base = event_base_new();
220: timeout = evtimer_new(base, on_timeout, NULL);
221:
222: curl_handle = curl_multi_init();
223: curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket);
224: curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout);
225:
226: while(argc-- > 1) {
227: add_download(argv[argc], argc);
228: }
229:
230: event_base_dispatch(base);
231:
232: curl_multi_cleanup(curl_handle);
233: event_free(timeout);
234: event_base_free(base);
235:
236: libevent_global_shutdown();
237: curl_global_cleanup();
238:
239: return 0;
240: }
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