1 #[cfg(test)]
2 use std::io::{self, Read};
3 
4 #[cfg(test)]
5 pub struct WouldBlockReader<R> {
6     inner: R,
7     do_block: bool,
8 }
9 #[cfg(test)]
10 impl<R: Read> WouldBlockReader<R> {
new(inner: R) -> Self11     pub fn new(inner: R) -> Self {
12         WouldBlockReader {
13             inner,
14             do_block: false,
15         }
16     }
17 }
18 #[cfg(test)]
19 impl<R: Read> Read for WouldBlockReader<R> {
read(&mut self, buf: &mut [u8]) -> io::Result<usize>20     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
21         self.do_block = !self.do_block;
22         if self.do_block {
23             Err(io::Error::new(io::ErrorKind::WouldBlock, "Would block"))
24         } else if buf.is_empty() {
25             Ok(0)
26         } else {
27             let mut byte = [0; 1];
28             if self.inner.read(&mut byte[..])? == 1 {
29                 buf[0] = byte[0];
30                 Ok(1)
31             } else {
32                 Ok(0)
33             }
34         }
35     }
36 }
37 
38 #[cfg(test)]
nb_read_to_end<R: Read>(mut reader: R) -> io::Result<Vec<u8>>39 pub fn nb_read_to_end<R: Read>(mut reader: R) -> io::Result<Vec<u8>> {
40     let mut buf = vec![0; 1024];
41     let mut offset = 0;
42     loop {
43         match reader.read(&mut buf[offset..]) {
44             Err(e) => {
45                 if e.kind() != io::ErrorKind::WouldBlock {
46                     return Err(e);
47                 }
48             }
49             Ok(0) => {
50                 buf.truncate(offset);
51                 break;
52             }
53             Ok(size) => {
54                 offset += size;
55                 if offset == buf.len() {
56                     buf.resize(offset * 2, 0);
57                 }
58             }
59         }
60     }
61     Ok(buf)
62 }
63