From: Daniel Stenberg Date: Sat, 27 Jul 2024 16:11:55 +0000 (+0200) Subject: example/multi-uv: remove the use of globals X-Git-Tag: curl-8_9_1~32 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b446802feb762b02a60d25a7d62c28a9dac87726;p=thirdparty%2Fcurl.git example/multi-uv: remove the use of globals - shows how to pass on local variables (better) - start the transfers nicer (with curl_multi_socket_action) - consistent and helpful function naming - to better show what functions and callbacks that are used for what - build warning-free with gcc -W -Wall -pedantic Closes #14287 --- diff --git a/docs/examples/multi-uv.c b/docs/examples/multi-uv.c index 3e967ccd8d..27a0731943 100644 --- a/docs/examples/multi-uv.c +++ b/docs/examples/multi-uv.c @@ -26,12 +26,12 @@ * multi_socket API using libuv * */ -/* Example application using the multi socket interface to download multiple - files in parallel, powered by libuv. +/* Use the socket_action interface to download multiple files in parallel, + powered by libuv. Requires libuv and (of course) libcurl. - See https://nikhilm.github.io/uvbook/ for more information on libuv. + See https://docs.libuv.org/en/v1.x/index.html libuv API documentation */ #include @@ -39,24 +39,30 @@ #include #include -uv_loop_t *loop; -CURLM *curl_handle; -uv_timer_t timeout; +/* object to pass to the callbacks */ +struct datauv { + uv_timer_t timeout; + uv_loop_t *loop; + CURLM *multi; +}; typedef struct curl_context_s { uv_poll_t poll_handle; curl_socket_t sockfd; + struct datauv *uv; } curl_context_t; -static curl_context_t *create_curl_context(curl_socket_t sockfd) +static curl_context_t *create_curl_context(curl_socket_t sockfd, + struct datauv *uv) { curl_context_t *context; context = (curl_context_t *) malloc(sizeof(*context)); context->sockfd = sockfd; + context->uv = uv; - uv_poll_init_socket(loop, &context->poll_handle, sockfd); + uv_poll_init_socket(uv->loop, &context->poll_handle, sockfd); context->poll_handle.data = context; return context; @@ -73,7 +79,7 @@ static void destroy_curl_context(curl_context_t *context) uv_close((uv_handle_t *) &context->poll_handle, curl_close_cb); } -static void add_download(const char *url, int num) +static void add_download(const char *url, int num, CURLM *multi) { char filename[50]; FILE *file; @@ -91,11 +97,11 @@ static void add_download(const char *url, int num) 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); + curl_multi_add_handle(multi, handle); fprintf(stderr, "Added download %s -> %s\n", url, filename); } -static void check_multi_info(void) +static void check_multi_info(curl_context_t *context) { char *done_url; CURLMsg *message; @@ -103,7 +109,7 @@ static void check_multi_info(void) CURL *easy_handle; FILE *file; - while((message = curl_multi_info_read(curl_handle, &pending))) { + while((message = curl_multi_info_read(context->uv->multi, &pending))) { switch(message->msg) { case CURLMSG_DONE: /* Do not use message data after calling curl_multi_remove_handle() and @@ -117,7 +123,7 @@ static void check_multi_info(void) curl_easy_getinfo(easy_handle, CURLINFO_PRIVATE, &file); printf("%s DONE\n", done_url); - curl_multi_remove_handle(curl_handle, easy_handle); + curl_multi_remove_handle(context->uv->multi, easy_handle); curl_easy_cleanup(easy_handle); if(file) { fclose(file); @@ -131,73 +137,82 @@ static void check_multi_info(void) } } -static void curl_perform(uv_poll_t *req, int status, int events) +/* callback from libuv on socket activity */ +static void on_uv_socket(uv_poll_t *req, int status, int events) { int running_handles; int flags = 0; - curl_context_t *context; - + curl_context_t *context = (curl_context_t *) req->data; + (void)status; if(events & UV_READABLE) flags |= CURL_CSELECT_IN; if(events & UV_WRITABLE) flags |= CURL_CSELECT_OUT; - context = (curl_context_t *) req->data; - - curl_multi_socket_action(curl_handle, context->sockfd, flags, + curl_multi_socket_action(context->uv->multi, context->sockfd, flags, &running_handles); - - check_multi_info(); + check_multi_info(context); } -static void on_timeout(uv_timer_t *req) +/* callback from libuv when timeout expires */ +static void on_uv_timeout(uv_timer_t *req) { - int running_handles; - curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0, - &running_handles); - check_multi_info(); + curl_context_t *context = (curl_context_t *) req->data; + if(context) { + int running_handles; + curl_multi_socket_action(context->uv->multi, CURL_SOCKET_TIMEOUT, 0, + &running_handles); + check_multi_info(context); + } } -static int start_timeout(CURLM *multi, long timeout_ms, void *userp) +/* callback from libcurl to update the timeout expiry */ +static int cb_timeout(CURLM *multi, long timeout_ms, + struct datauv *uv) { - if(timeout_ms < 0) { - uv_timer_stop(&timeout); - } + (void)multi; + if(timeout_ms < 0) + uv_timer_stop(&uv->timeout); else { if(timeout_ms == 0) - timeout_ms = 1; /* 0 means call socket_action asap */ - uv_timer_start(&timeout, on_timeout, timeout_ms, 0); + timeout_ms = 1; /* 0 means call curl_multi_socket_action asap but NOT + within the callback itself */ + uv_timer_start(&uv->timeout, on_uv_timeout, timeout_ms, + 0); /* do not repeat */ } return 0; } -static int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp, - void *socketp) +/* callback from libcurl to update socket activity to wait for */ +static int cb_socket(CURL *easy, curl_socket_t s, int action, + struct datauv *uv, + void *socketp) { curl_context_t *curl_context; int events = 0; + (void)easy; 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_context_t *) socketp : create_curl_context(s, uv); - curl_multi_assign(curl_handle, s, (void *) curl_context); + curl_multi_assign(uv->multi, s, (void *) curl_context); if(action != CURL_POLL_IN) events |= UV_WRITABLE; if(action != CURL_POLL_OUT) events |= UV_READABLE; - uv_poll_start(&curl_context->poll_handle, events, curl_perform); + uv_poll_start(&curl_context->poll_handle, events, on_uv_socket); break; case CURL_POLL_REMOVE: if(socketp) { uv_poll_stop(&((curl_context_t*)socketp)->poll_handle); destroy_curl_context((curl_context_t*) socketp); - curl_multi_assign(curl_handle, s, NULL); + curl_multi_assign(uv->multi, s, NULL); } break; default: @@ -209,28 +224,31 @@ static int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp, int main(int argc, char **argv) { - loop = uv_default_loop(); + struct datauv uv = { 0 }; + int running_handles; if(argc <= 1) return 0; - if(curl_global_init(CURL_GLOBAL_ALL)) { - fprintf(stderr, "Could not init curl\n"); - return 1; - } + curl_global_init(CURL_GLOBAL_ALL); - uv_timer_init(loop, &timeout); + uv.loop = uv_default_loop(); + uv_timer_init(uv.loop, &uv.timeout); - curl_handle = curl_multi_init(); - curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket); - curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout); + uv.multi = curl_multi_init(); + curl_multi_setopt(uv.multi, CURLMOPT_SOCKETFUNCTION, cb_socket); + curl_multi_setopt(uv.multi, CURLMOPT_SOCKETDATA, &uv); + curl_multi_setopt(uv.multi, CURLMOPT_TIMERFUNCTION, cb_timeout); + curl_multi_setopt(uv.multi, CURLMOPT_TIMERDATA, &uv); while(argc-- > 1) { - add_download(argv[argc], argc); + add_download(argv[argc], argc, uv.multi); } - uv_run(loop, UV_RUN_DEFAULT); - curl_multi_cleanup(curl_handle); + /* kickstart the thing */ + curl_multi_socket_action(uv.multi, CURL_SOCKET_TIMEOUT, 0, &running_handles); + uv_run(uv.loop, UV_RUN_DEFAULT); + curl_multi_cleanup(uv.multi); return 0; }