1 use std::io::{self, BufRead};
2 use std::mem;
3
4 use futures::{Poll, Stream};
5
6 use AsyncRead;
7
8 /// Combinator created by the top-level `lines` method which is a stream over
9 /// the lines of text on an I/O object.
10 #[derive(Debug)]
11 pub struct Lines<A> {
12 io: A,
13 line: String,
14 }
15
16 /// Creates a new stream from the I/O object given representing the lines of
17 /// input that are found on `A`.
18 ///
19 /// This method takes an asynchronous I/O object, `a`, and returns a `Stream` of
20 /// lines that the object contains. The returned stream will reach its end once
21 /// `a` reaches EOF.
lines<A>(a: A) -> Lines<A> where A: AsyncRead + BufRead,22 pub fn lines<A>(a: A) -> Lines<A>
23 where
24 A: AsyncRead + BufRead,
25 {
26 Lines {
27 io: a,
28 line: String::new(),
29 }
30 }
31
32 impl<A> Lines<A> {
33 /// Returns the underlying I/O object.
34 ///
35 /// Note that this may lose data already read into internal buffers. It's
36 /// recommended to only call this once the stream has reached its end.
into_inner(self) -> A37 pub fn into_inner(self) -> A {
38 self.io
39 }
40 }
41
42 impl<A> Stream for Lines<A>
43 where
44 A: AsyncRead + BufRead,
45 {
46 type Item = String;
47 type Error = io::Error;
48
poll(&mut self) -> Poll<Option<String>, io::Error>49 fn poll(&mut self) -> Poll<Option<String>, io::Error> {
50 let n = try_nb!(self.io.read_line(&mut self.line));
51 if n == 0 && self.line.len() == 0 {
52 return Ok(None.into());
53 }
54 if self.line.ends_with("\n") {
55 self.line.pop();
56 if self.line.ends_with("\r") {
57 self.line.pop();
58 }
59 }
60 Ok(Some(mem::replace(&mut self.line, String::new())).into())
61 }
62 }
63