xref: /third_party/libuv/docs/code/uvtee/main.c (revision e66f31c5) 
1#include <stdio.h>
2#include <fcntl.h>
3#include <string.h>
4#include <stdlib.h>
5
6#include <uv.h>
7
8typedef struct {
9    uv_write_t req;
10    uv_buf_t buf;
11} write_req_t;
12
13uv_loop_t *loop;
14uv_pipe_t stdin_pipe;
15uv_pipe_t stdout_pipe;
16uv_pipe_t file_pipe;
17
18void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
19    *buf = uv_buf_init((char*) malloc(suggested_size), suggested_size);
20}
21
22void free_write_req(uv_write_t *req) {
23    write_req_t *wr = (write_req_t*) req;
24    free(wr->buf.base);
25    free(wr);
26}
27
28void on_stdout_write(uv_write_t *req, int status) {
29    free_write_req(req);
30}
31
32void on_file_write(uv_write_t *req, int status) {
33    free_write_req(req);
34}
35
36void write_data(uv_stream_t *dest, size_t size, uv_buf_t buf, uv_write_cb cb) {
37    write_req_t *req = (write_req_t*) malloc(sizeof(write_req_t));
38    req->buf = uv_buf_init((char*) malloc(size), size);
39    memcpy(req->buf.base, buf.base, size);
40    uv_write((uv_write_t*) req, (uv_stream_t*)dest, &req->buf, 1, cb);
41}
42
43void read_stdin(uv_stream_t *stream, ssize_t nread, const uv_buf_t *buf) {
44    if (nread < 0){
45        if (nread == UV_EOF){
46            // end of file
47            uv_close((uv_handle_t *)&stdin_pipe, NULL);
48            uv_close((uv_handle_t *)&stdout_pipe, NULL);
49            uv_close((uv_handle_t *)&file_pipe, NULL);
50        }
51    } else if (nread > 0) {
52        write_data((uv_stream_t *)&stdout_pipe, nread, *buf, on_stdout_write);
53        write_data((uv_stream_t *)&file_pipe, nread, *buf, on_file_write);
54    }
55
56    // OK to free buffer as write_data copies it.
57    if (buf->base)
58        free(buf->base);
59}
60
61int main(int argc, char **argv) {
62    loop = uv_default_loop();
63
64    uv_pipe_init(loop, &stdin_pipe, 0);
65    uv_pipe_open(&stdin_pipe, 0);
66
67    uv_pipe_init(loop, &stdout_pipe, 0);
68    uv_pipe_open(&stdout_pipe, 1);
69
70    uv_fs_t file_req;
71    int fd = uv_fs_open(loop, &file_req, argv[1], O_CREAT | O_RDWR, 0644, NULL);
72    uv_pipe_init(loop, &file_pipe, 0);
73    uv_pipe_open(&file_pipe, fd);
74
75    uv_read_start((uv_stream_t*)&stdin_pipe, alloc_buffer, read_stdin);
76
77    uv_run(loop, UV_RUN_DEFAULT);
78    return 0;
79}
80