#include <assert.h>
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <uv.h>
void on_read(uv_fs_t *req);
uv_fs_t open_req;
uv_fs_t read_req;
uv_fs_t write_req;
static char buffer[1024];
static uv_buf_t iov;
void on_write(uv_fs_t *req) {
if (req->result < 0) {
fprintf(stderr, "Write error: %s\n", uv_strerror((int)req->result));
}
else {
uv_fs_read(uv_default_loop(), &read_req, open_req.result, &iov, 1, -1, on_read);
}
}
void on_read(uv_fs_t *req) {
if (req->result < 0) {
fprintf(stderr, "Read error: %s\n", uv_strerror(req->result));
}
else if (req->result == 0) {
uv_fs_t close_req;
// synchronous
uv_fs_close(uv_default_loop(), &close_req, open_req.result, NULL);
}
else if (req->result > 0) {
iov.len = req->result;
uv_fs_write(uv_default_loop(), &write_req, 1, &iov, 1, -1, on_write);
}
}
void on_open(uv_fs_t *req) {
// The request passed to the callback is the same as the one the call setup
// function was passed.
assert(req == &open_req);
if (req->result >= 0) {
iov = uv_buf_init(buffer, sizeof(buffer));
uv_fs_read(uv_default_loop(), &read_req, req->result,
&iov, 1, -1, on_read);
}
else {
fprintf(stderr, "error opening file: %s\n", uv_strerror((int)req->result));
}
}
int main(int argc, char **argv) {
uv_fs_open(uv_default_loop(), &open_req, argv[1], O_RDONLY, 0, on_open);
uv_run(uv_default_loop(), UV_RUN_DEFAULT);
uv_fs_req_cleanup(&open_req);
uv_fs_req_cleanup(&read_req);
uv_fs_req_cleanup(&write_req);
return 0;
}