1 use crate::Buf;
2
3 use std::{cmp, io};
4
5 /// A `Buf` adapter which implements `io::Read` for the inner value.
6 ///
7 /// This struct is generally created by calling `reader()` on `Buf`. See
8 /// documentation of [`reader()`](trait.Buf.html#method.reader) for more
9 /// details.
10 #[derive(Debug)]
11 pub struct Reader<B> {
12 buf: B,
13 }
14
new<B>(buf: B) -> Reader<B>15 pub fn new<B>(buf: B) -> Reader<B> {
16 Reader { buf }
17 }
18
19 impl<B: Buf> Reader<B> {
20 /// Gets a reference to the underlying `Buf`.
21 ///
22 /// It is inadvisable to directly read from the underlying `Buf`.
23 ///
24 /// # Examples
25 ///
26 /// ```rust
27 /// use bytes::buf::BufExt;
28 ///
29 /// let buf = b"hello world".reader();
30 ///
31 /// assert_eq!(b"hello world", buf.get_ref());
32 /// ```
get_ref(&self) -> &B33 pub fn get_ref(&self) -> &B {
34 &self.buf
35 }
36
37 /// Gets a mutable reference to the underlying `Buf`.
38 ///
39 /// It is inadvisable to directly read from the underlying `Buf`.
get_mut(&mut self) -> &mut B40 pub fn get_mut(&mut self) -> &mut B {
41 &mut self.buf
42 }
43
44 /// Consumes this `Reader`, returning the underlying value.
45 ///
46 /// # Examples
47 ///
48 /// ```rust
49 /// use bytes::{Buf, buf::BufExt};
50 /// use std::io;
51 ///
52 /// let mut buf = b"hello world".reader();
53 /// let mut dst = vec![];
54 ///
55 /// io::copy(&mut buf, &mut dst).unwrap();
56 ///
57 /// let buf = buf.into_inner();
58 /// assert_eq!(0, buf.remaining());
59 /// ```
into_inner(self) -> B60 pub fn into_inner(self) -> B {
61 self.buf
62 }
63 }
64
65 impl<B: Buf + Sized> io::Read for Reader<B> {
read(&mut self, dst: &mut [u8]) -> io::Result<usize>66 fn read(&mut self, dst: &mut [u8]) -> io::Result<usize> {
67 let len = cmp::min(self.buf.remaining(), dst.len());
68
69 Buf::copy_to_slice(&mut self.buf, &mut dst[0..len]);
70 Ok(len)
71 }
72 }
73
74 impl<B: Buf + Sized> io::BufRead for Reader<B> {
fill_buf(&mut self) -> io::Result<&[u8]>75 fn fill_buf(&mut self) -> io::Result<&[u8]> {
76 Ok(self.buf.bytes())
77 }
consume(&mut self, amt: usize)78 fn consume(&mut self, amt: usize) {
79 self.buf.advance(amt)
80 }
81 }
82