1#include <assert.h>
2#include <stdio.h>
3#include <stdlib.h>
4#include <uv.h>
5#include <curl/curl.h>
6
7uv_loop_t *loop;
8CURLM *curl_handle;
9uv_timer_t timeout;
10
11typedef struct curl_context_s {
12    uv_poll_t poll_handle;
13    curl_socket_t sockfd;
14} curl_context_t;
15
16curl_context_t *create_curl_context(curl_socket_t sockfd) {
17    curl_context_t *context;
18
19    context = (curl_context_t*) malloc(sizeof *context);
20
21    context->sockfd = sockfd;
22
23    int r = uv_poll_init_socket(loop, &context->poll_handle, sockfd);
24    assert(r == 0);
25    context->poll_handle.data = context;
26
27    return context;
28}
29
30void curl_close_cb(uv_handle_t *handle) {
31    curl_context_t *context = (curl_context_t*) handle->data;
32    free(context);
33}
34
35void destroy_curl_context(curl_context_t *context) {
36    uv_close((uv_handle_t*) &context->poll_handle, curl_close_cb);
37}
38
39
40void add_download(const char *url, int num) {
41    char filename[50];
42    sprintf(filename, "%d.download", num);
43    FILE *file;
44
45    file = fopen(filename, "w");
46    if (file == NULL) {
47        fprintf(stderr, "Error opening %s\n", filename);
48        return;
49    }
50
51    CURL *handle = curl_easy_init();
52    curl_easy_setopt(handle, CURLOPT_WRITEDATA, file);
53    curl_easy_setopt(handle, CURLOPT_URL, url);
54    curl_multi_add_handle(curl_handle, handle);
55    fprintf(stderr, "Added download %s -> %s\n", url, filename);
56}
57
58void check_multi_info(void) {
59    char *done_url;
60    CURLMsg *message;
61    int pending;
62
63    while ((message = curl_multi_info_read(curl_handle, &pending))) {
64        switch (message->msg) {
65        case CURLMSG_DONE:
66            curl_easy_getinfo(message->easy_handle, CURLINFO_EFFECTIVE_URL,
67                            &done_url);
68            printf("%s DONE\n", done_url);
69
70            curl_multi_remove_handle(curl_handle, message->easy_handle);
71            curl_easy_cleanup(message->easy_handle);
72            break;
73
74        default:
75            fprintf(stderr, "CURLMSG default\n");
76            abort();
77        }
78    }
79}
80
81void curl_perform(uv_poll_t *req, int status, int events) {
82    uv_timer_stop(&timeout);
83    int running_handles;
84    int flags = 0;
85    if (status < 0)                      flags = CURL_CSELECT_ERR;
86    if (!status && events & UV_READABLE) flags |= CURL_CSELECT_IN;
87    if (!status && events & UV_WRITABLE) flags |= CURL_CSELECT_OUT;
88
89    curl_context_t *context;
90
91    context = (curl_context_t*)req;
92
93    curl_multi_socket_action(curl_handle, context->sockfd, flags, &running_handles);
94    check_multi_info();
95}
96
97void on_timeout(uv_timer_t *req) {
98    int running_handles;
99    curl_multi_socket_action(curl_handle, CURL_SOCKET_TIMEOUT, 0, &running_handles);
100    check_multi_info();
101}
102
103void start_timeout(CURLM *multi, long timeout_ms, void *userp) {
104    if (timeout_ms <= 0)
105        timeout_ms = 1; /* 0 means directly call socket_action, but we'll do it in a bit */
106    uv_timer_start(&timeout, on_timeout, timeout_ms, 0);
107}
108
109int handle_socket(CURL *easy, curl_socket_t s, int action, void *userp, void *socketp) {
110    curl_context_t *curl_context;
111    if (action == CURL_POLL_IN || action == CURL_POLL_OUT) {
112        if (socketp) {
113            curl_context = (curl_context_t*) socketp;
114        }
115        else {
116            curl_context = create_curl_context(s);
117            curl_multi_assign(curl_handle, s, (void *) curl_context);
118        }
119    }
120
121    switch (action) {
122        case CURL_POLL_IN:
123            uv_poll_start(&curl_context->poll_handle, UV_READABLE, curl_perform);
124            break;
125        case CURL_POLL_OUT:
126            uv_poll_start(&curl_context->poll_handle, UV_WRITABLE, curl_perform);
127            break;
128        case CURL_POLL_REMOVE:
129            if (socketp) {
130                uv_poll_stop(&((curl_context_t*)socketp)->poll_handle);
131                destroy_curl_context((curl_context_t*) socketp);
132                curl_multi_assign(curl_handle, s, NULL);
133            }
134            break;
135        default:
136            abort();
137    }
138
139    return 0;
140}
141
142int main(int argc, char **argv) {
143    loop = uv_default_loop();
144
145    if (argc <= 1)
146        return 0;
147
148    if (curl_global_init(CURL_GLOBAL_ALL)) {
149        fprintf(stderr, "Could not init cURL\n");
150        return 1;
151    }
152
153    uv_timer_init(loop, &timeout);
154
155    curl_handle = curl_multi_init();
156    curl_multi_setopt(curl_handle, CURLMOPT_SOCKETFUNCTION, handle_socket);
157    curl_multi_setopt(curl_handle, CURLMOPT_TIMERFUNCTION, start_timeout);
158
159    while (argc-- > 1) {
160        add_download(argv[argc], argc);
161    }
162
163    uv_run(loop, UV_RUN_DEFAULT);
164    curl_multi_cleanup(curl_handle);
165    return 0;
166}
167