1 #include <assert.h>
2 #include <stdio.h>
3 #include <fcntl.h>
4 #include <uv.h>
5
6 void on_read(uv_fs_t *req);
7
8 uv_fs_t open_req;
9 uv_fs_t read_req;
10 uv_fs_t write_req;
11
12 static char buffer[1024];
13
14 static uv_buf_t iov;
15
on_write(uv_fs_t * req)16 void on_write(uv_fs_t *req) {
17 if (req->result < 0) {
18 fprintf(stderr, "Write error: %s\n", uv_strerror((int)req->result));
19 }
20 else {
21 uv_fs_read(uv_default_loop(), &read_req, open_req.result, &iov, 1, -1, on_read);
22 }
23 }
24
on_read(uv_fs_t * req)25 void on_read(uv_fs_t *req) {
26 if (req->result < 0) {
27 fprintf(stderr, "Read error: %s\n", uv_strerror(req->result));
28 }
29 else if (req->result == 0) {
30 uv_fs_t close_req;
31 // synchronous
32 uv_fs_close(uv_default_loop(), &close_req, open_req.result, NULL);
33 }
34 else if (req->result > 0) {
35 iov.len = req->result;
36 uv_fs_write(uv_default_loop(), &write_req, 1, &iov, 1, -1, on_write);
37 }
38 }
39
on_open(uv_fs_t * req)40 void on_open(uv_fs_t *req) {
41 // The request passed to the callback is the same as the one the call setup
42 // function was passed.
43 assert(req == &open_req);
44 if (req->result >= 0) {
45 iov = uv_buf_init(buffer, sizeof(buffer));
46 uv_fs_read(uv_default_loop(), &read_req, req->result,
47 &iov, 1, -1, on_read);
48 }
49 else {
50 fprintf(stderr, "error opening file: %s\n", uv_strerror((int)req->result));
51 }
52 }
53
main(int argc,char ** argv)54 int main(int argc, char **argv) {
55 uv_fs_open(uv_default_loop(), &open_req, argv[1], O_RDONLY, 0, on_open);
56 uv_run(uv_default_loop(), UV_RUN_DEFAULT);
57
58 uv_fs_req_cleanup(&open_req);
59 uv_fs_req_cleanup(&read_req);
60 uv_fs_req_cleanup(&write_req);
61 return 0;
62 }
63
