use std::cmp::min;
use std::io::{Error, ErrorKind, Read, Result, Write};
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
pub struct MockStream {
read_buf: Vec<u8>,
read_pos: usize,
pub written_buf: Vec<u8>,
err_on_read: bool,
eof_on_read: bool,
read_delay: usize,
}
impl Default for MockStream {
fn default() -> Self {
MockStream {
read_buf: Vec::new(),
read_pos: 0,
written_buf: Vec::new(),
err_on_read: false,
eof_on_read: false,
read_delay: 0,
}
}
}
impl MockStream {
pub fn new(read_buf: Vec<u8>) -> MockStream {
MockStream::default().with_buf(read_buf)
}
pub fn with_buf(mut self, read_buf: Vec<u8>) -> MockStream {
self.read_buf = read_buf;
self
}
pub fn with_eof(mut self) -> MockStream {
self.eof_on_read = true;
self
}
pub fn with_err(mut self) -> MockStream {
self.err_on_read = true;
self
}
pub fn with_delay(mut self) -> MockStream {
self.read_delay = 1;
self
}
}
impl Read for MockStream {
fn read(&mut self, buf: &mut [u8]) -> Result<usize> {
if self.eof_on_read {
return Ok(0);
}
if self.err_on_read {
return Err(Error::new(ErrorKind::Other, "MockStream Error"));
}
if self.read_pos >= self.read_buf.len() {
return Err(Error::new(ErrorKind::UnexpectedEof, "EOF"));
}
let mut write_len = min(buf.len(), self.read_buf.len() - self.read_pos);
if self.read_delay > 0 {
self.read_delay -= 1;
write_len = min(write_len, 1);
}
let max_pos = self.read_pos + write_len;
for x in self.read_pos..max_pos {
buf[x - self.read_pos] = self.read_buf[x];
}
self.read_pos += write_len;
Ok(write_len)
}
}
impl Write for MockStream {
fn write(&mut self, buf: &[u8]) -> Result<usize> {
self.written_buf.extend_from_slice(buf);
Ok(buf.len())
}
fn flush(&mut self) -> Result<()> {
Ok(())
}
}