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authorAndrei Valeriu BICA <abica@bitdefender.com>2019-10-07 16:19:02 +0300
committerDaniel Stenberg <daniel@haxx.se>2019-10-07 17:58:12 +0200
commitb905e26b0573e0b98c36e958c901480ac249350c (patch)
treec087e7b50bd2216cc24354d437a56676dafea2df /docs/examples
parent8bb3a95ce1577e2c8282e7d1c2830bde87cf5c3b (diff)
docs: added multi-event.c example
Similar to multi-uv.c but using libevent 2. This is a simpler libevent integration example then hiperfifo.c. Closes #4471
Diffstat (limited to 'docs/examples')
-rw-r--r--docs/examples/Makefile.inc2
-rw-r--r--docs/examples/multi-event.c240
2 files changed, 241 insertions, 1 deletions
diff --git a/docs/examples/Makefile.inc b/docs/examples/Makefile.inc
index 6fd8ecd76..f03fcf2f0 100644
--- a/docs/examples/Makefile.inc
+++ b/docs/examples/Makefile.inc
@@ -45,4 +45,4 @@ COMPLICATED_EXAMPLES = curlgtk.c curlx.c htmltitle.cpp cacertinmem.c \
sampleconv.c synctime.c threaded-ssl.c evhiperfifo.c \
smooth-gtk-thread.c version-check.pl href_extractor.c asiohiper.cpp \
multi-uv.c xmlstream.c usercertinmem.c sessioninfo.c \
- threaded-shared-conn.c crawler.c ephiperfifo.c
+ threaded-shared-conn.c crawler.c ephiperfifo.c multi-event.c
diff --git a/docs/examples/multi-event.c b/docs/examples/multi-event.c
new file mode 100644
index 000000000..ce2791974
--- /dev/null
+++ b/docs/examples/multi-event.c
@@ -0,0 +1,240 @@
+/***************************************************************************
+ * _ _ ____ _
+ * Project ___| | | | _ \| |
+ * / __| | | | |_) | |
+ * | (__| |_| | _ <| |___
+ * \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
+ *
+ * This software is licensed as described in the file COPYING, which
+ * you should have received as part of this distribution. The terms
+ * are also available at https://curl.haxx.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ***************************************************************************/
+
+/* <DESC>
+ * multi_socket API using libevent
+ * </DESC>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <event2/event.h>
+#include <curl/curl.h>
+
+struct event_base *base;
+CURLM *curl_handle;
+struct event *timeout;
+
+typedef struct curl_context_s {
+ struct event *event;
+ curl_socket_t sockfd;
+} curl_context_t;
+
+static void curl_perform(int fd, short event, void *arg);
+
+static curl_context_t* create_curl_context(curl_socket_t sockfd)
+{
+ curl_context_t *context;
+
+ context = (curl_context_t *) malloc(sizeof(*context));
+
+ context->sockfd = sockfd;
+
+ context->event = event_new(base, sockfd, 0, curl_perform, context);
+
+ return context;
+}
+
+static void destroy_curl_context(curl_context_t *context)
+{
+ event_del(context->event);
+ event_free(context->event);
+ free(context);
+}
+
+static void add_download(const char *url, int num)
+{
+ char filename[50];
+ FILE *file;
+ CURL *handle;
+
+ snprintf(filename, 50, "%d.download", num);
+
+ file = fopen(filename, "wb");
+ if(!file) {
+ fprintf(stderr, "Error opening %s\n", filename);
+ return;
+ }
+
+ handle = curl_easy_init();
+ curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
+ curl_easy_setopt(handle, CURLOPT_PRIVATE, file);
+ curl_easy_setopt(handle, CURLOPT_URL, url);
+ curl_multi_add_handle(curl_handle, handle);
+ fprintf(stderr, "Added download %s -> %s\n", url, filename);
+}
+
+static void check_multi_info(void)
+{
+ char *done_url;
+ CURLMsg *message;
+ int pending;
+ CURL *easy_handle;
+ FILE *file;
+
+ while((message = curl_multi_info_read(curl_handle, &pending))) {
+ switch(message->msg) {
+ case CURLMSG_DONE:
+ /* Do not use message data after calling curl_multi_remove_handle() and
+ curl_easy_cleanup(). As per curl_multi_info_read() docs:
+ "WARNING: The data the returned pointer points to will not survive
+ calling curl_multi_cleanup, curl_multi_remove_handle or
+ curl_easy_cleanup." */
+ easy_handle = message->easy_handle;
+
+ curl_easy_getinfo(easy_handle, CURLINFO_EFFECTIVE_URL, &done_url);
+ curl_easy_getinfo(easy_handle, CURLINFO_PRIVATE, &file);
+ printf("%s DONE\n", done_url);
+
+ curl_multi_remove_handle(curl_handle, easy_handle);
+ curl_easy_cleanup(easy_handle);
+ if(file) {
+ fclose(file);
+ }
+ break;
+
+ default:
+ fprintf(stderr, "CURLMSG default\n");
+ break;
+ }
+ }
+}
+
+static void curl_perform(int fd, short event, void *arg)
+{
+ int running_handles;
+ int flags = 0;
+ curl_context_t *context;
+
+ if(event & EV_READ)
+ flags |= CURL_CSELECT_IN;
+ if(event & EV_WRITE)
+ flags |= CURL_CSELECT_OUT;
+
+ context = (curl_context_t *) arg;
+
+ curl_multi_socket_action(curl_handle, context->sockfd, flags,
+ &running_handles);
+
+ check_multi_info();
+}
+
+static void on_timeout(evutil_socket_t fd, short events, void *arg)
+{
+ int running_handles;
+ curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0,
+ &running_handles);
+ check_multi_info();
+}
+
+static int start_timeout(CURLM *multi, long timeout_ms, void *userp)
+{
+ if(timeout_ms < 0) {
+ evtimer_del(timeout);
+ }
+ else {
+ if(timeout_ms == 0)
+ timeout_ms = 1; /* 0 means directly call socket_action, but we'll do it
+ in a bit */
+ struct timeval tv;
+ tv.tv_sec = timeout_ms / 1000;
+ tv.tv_usec = (timeout_ms % 1000) * 1000;
+ evtimer_del(timeout);
+ evtimer_add(timeout, &tv);
+ }
+ return 0;
+}
+
+static int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp,
+ void *socketp)
+{
+ curl_context_t *curl_context;
+ int events = 0;
+
+ switch(action) {
+ case CURL_POLL_IN:
+ case CURL_POLL_OUT:
+ case CURL_POLL_INOUT:
+ curl_context = socketp ?
+ (curl_context_t *) socketp : create_curl_context(s);
+
+ curl_multi_assign(curl_handle, s, (void *) curl_context);
+
+ if(action != CURL_POLL_IN)
+ events |= EV_WRITE;
+ if(action != CURL_POLL_OUT)
+ events |= EV_READ;
+
+ events |= EV_PERSIST;
+
+ event_del(curl_context->event);
+ event_assign(curl_context->event, base, curl_context->sockfd, events,
+ curl_perform, curl_context);
+ event_add(curl_context->event, NULL);
+
+ break;
+ case CURL_POLL_REMOVE:
+ if(socketp) {
+ event_del(((curl_context_t*) socketp)->event);
+ destroy_curl_context((curl_context_t*) socketp);
+ curl_multi_assign(curl_handle, s, NULL);
+ }
+ break;
+ default:
+ abort();
+ }
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ if(argc <= 1)
+ return 0;
+
+ if(curl_global_init(CURL_GLOBAL_ALL)) {
+ fprintf(stderr, "Could not init curl\n");
+ return 1;
+ }
+
+ base = event_base_new();
+ timeout = evtimer_new(base, on_timeout, NULL);
+
+ curl_handle = curl_multi_init();
+ curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket);
+ curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout);
+
+ while(argc-- > 1) {
+ add_download(argv[argc], argc);
+ }
+
+ event_base_dispatch(base);
+
+ curl_multi_cleanup(curl_handle);
+ event_free(timeout);
+ event_base_free(base);
+
+ libevent_global_shutdown();
+ curl_global_cleanup();
+
+ return 0;
+}