compio_io/read/
mod.rs

1#[cfg(feature = "allocator_api")]
2use std::alloc::Allocator;
3use std::{io::Cursor, rc::Rc, sync::Arc};
4
5use compio_buf::{
6    BufResult, IntoInner, IoBufMut, IoBufMutExt, IoVectoredBufMut, SetLenExt, buf_try, t_alloc,
7};
8
9mod buf;
10#[macro_use]
11mod ext;
12mod managed;
13mod multi;
14
15pub use buf::*;
16pub use ext::*;
17pub use managed::*;
18pub use multi::*;
19
20use crate::util::{slice_to_buf, slice_to_uninit};
21
22/// AsyncRead
23///
24/// Async read with a ownership of a buffer
25pub trait AsyncRead {
26    /// Read some bytes from this source into the [`IoBufMut`] buffer and return
27    /// a [`BufResult`], consisting of the buffer and a [`usize`] indicating
28    /// how many bytes were read.
29    ///
30    /// # Caution
31    /// - This function read data to the **beginning** of the buffer; that is,
32    ///   all existing data in the buffer will be overwritten. To read data to
33    ///   the end of the buffer, use [`AsyncReadExt::append`].
34    /// - Implementor **MUST** update the buffer init via [`SetLen::set_len`]
35    ///   after reading, and no further update should be made by caller.
36    ///
37    /// [`SetLen::set_len`]: compio_buf::SetLen::set_len
38    async fn read<B: IoBufMut>(&mut self, buf: B) -> BufResult<usize, B>;
39
40    /// Like `read`, except that it reads into a type implements
41    /// [`IoVectoredBufMut`].
42    ///
43    /// The default implementation will read only to first buffer in `buf` with
44    /// non-zero capacity and return, meaning it's possible and likely that not
45    /// all buffer space is filled. If guaranteed full read is desired,
46    /// it is recommended to use [`AsyncReadExt::read_vectored_exact`] instead.
47    ///
48    /// # Caution
49    ///
50    /// Implementor **MUST** update the buffer init via
51    /// [`SetLen::set_len`] after reading.
52    ///
53    /// [`SetLen::set_len`]: compio_buf::SetLen::set_len
54    async fn read_vectored<V: IoVectoredBufMut>(&mut self, buf: V) -> BufResult<usize, V> {
55        loop_read_vectored!(buf, iter, self.read(iter))
56    }
57}
58
59impl<A: AsyncRead + ?Sized> AsyncRead for &mut A {
60    #[inline(always)]
61    async fn read<T: IoBufMut>(&mut self, buf: T) -> BufResult<usize, T> {
62        (**self).read(buf).await
63    }
64
65    #[inline(always)]
66    async fn read_vectored<T: IoVectoredBufMut>(&mut self, buf: T) -> BufResult<usize, T> {
67        (**self).read_vectored(buf).await
68    }
69}
70
71impl<R: AsyncRead + ?Sized, #[cfg(feature = "allocator_api")] A: Allocator> AsyncRead
72    for t_alloc!(Box, R, A)
73{
74    #[inline(always)]
75    async fn read<T: IoBufMut>(&mut self, buf: T) -> BufResult<usize, T> {
76        (**self).read(buf).await
77    }
78
79    #[inline(always)]
80    async fn read_vectored<T: IoVectoredBufMut>(&mut self, buf: T) -> BufResult<usize, T> {
81        (**self).read_vectored(buf).await
82    }
83}
84
85impl AsyncRead for &[u8] {
86    #[inline]
87    async fn read<T: IoBufMut>(&mut self, mut buf: T) -> BufResult<usize, T> {
88        let len = slice_to_buf(self, &mut buf);
89        *self = &self[len..];
90        BufResult(Ok(len), buf)
91    }
92
93    async fn read_vectored<T: IoVectoredBufMut>(&mut self, mut buf: T) -> BufResult<usize, T> {
94        let mut this = *self; // An immutable slice to track the read position
95
96        for buf in buf.iter_uninit_slice() {
97            let n = slice_to_uninit(this, buf);
98            this = &this[n..];
99            if this.is_empty() {
100                break;
101            }
102        }
103
104        let len = self.len() - this.len();
105        *self = this;
106
107        unsafe {
108            buf.advance_vec_to(len);
109        }
110
111        BufResult(Ok(len), buf)
112    }
113}
114
115/// # AsyncReadAt
116///
117/// Async read with a ownership of a buffer and a position
118pub trait AsyncReadAt {
119    /// Like [`AsyncRead::read`], except that it reads at a specified position.
120    async fn read_at<T: IoBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T>;
121
122    /// Like [`AsyncRead::read_vectored`], except that it reads at a specified
123    /// position.
124    async fn read_vectored_at<T: IoVectoredBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
125        loop_read_vectored!(buf, iter, self.read_at(iter, pos))
126    }
127}
128
129macro_rules! impl_read_at {
130    (@ptr $($ty:ty),*) => {
131        $(
132            impl<A: AsyncReadAt + ?Sized> AsyncReadAt for $ty {
133                async fn read_at<T: IoBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
134                    (**self).read_at(buf, pos).await
135                }
136
137                async fn read_vectored_at<T: IoVectoredBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
138                    (**self).read_vectored_at(buf, pos).await
139                }
140            }
141        )*
142    };
143
144    (@ptra $($ty:ident),*) => {
145        $(
146            #[cfg(feature = "allocator_api")]
147            impl<R: AsyncReadAt + ?Sized, A: Allocator> AsyncReadAt for $ty<R, A> {
148                async fn read_at<T: IoBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
149                    (**self).read_at(buf, pos).await
150                }
151
152                async fn read_vectored_at<T: IoVectoredBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
153                    (**self).read_vectored_at(buf, pos).await
154                }
155            }
156            #[cfg(not(feature = "allocator_api"))]
157            impl_read_at!(@ptr $ty<A>);
158        )*
159    };
160
161    (@slice $($(const $len:ident =>)? $ty:ty), *) => {
162        $(
163            impl<$(const $len: usize)?> AsyncReadAt for $ty {
164                async fn read_at<T: IoBufMut>(&self, mut buf: T, pos: u64) -> BufResult<usize, T> {
165                    let pos = pos.min(self.len() as u64);
166                    let len = slice_to_buf(&self[pos as usize..], &mut buf);
167                    BufResult(Ok(len), buf)
168                }
169
170                async fn read_vectored_at<T:IoVectoredBufMut>(&self, mut buf: T, pos: u64) -> BufResult<usize, T> {
171                    let slice = &self[pos as usize..];
172                    let mut this = slice;
173
174                    for buf in buf.iter_uninit_slice() {
175                        let n = slice_to_uninit(this, buf);
176                        this = &this[n..];
177                        if this.is_empty() {
178                            break;
179                        }
180                    }
181
182                    let len = slice.len() - this.len();
183                    unsafe {
184                        buf.advance_vec_to(len);
185                    }
186
187                    BufResult(Ok(len), buf)
188                }
189            }
190        )*
191    }
192}
193
194impl_read_at!(@ptr &A, &mut A);
195impl_read_at!(@ptra Box, Rc, Arc);
196impl_read_at!(@slice [u8], const LEN => [u8; LEN]);
197
198impl<#[cfg(feature = "allocator_api")] A: Allocator> AsyncReadAt for t_alloc!(Vec, u8, A) {
199    async fn read_at<T: IoBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
200        self.as_slice().read_at(buf, pos).await
201    }
202
203    async fn read_vectored_at<T: IoVectoredBufMut>(&self, buf: T, pos: u64) -> BufResult<usize, T> {
204        self.as_slice().read_vectored_at(buf, pos).await
205    }
206}
207
208impl<A: AsyncReadAt> AsyncRead for Cursor<A> {
209    #[inline]
210    async fn read<T: IoBufMut>(&mut self, buf: T) -> BufResult<usize, T> {
211        let pos = self.position();
212        let (n, buf) = buf_try!(self.get_ref().read_at(buf, pos).await);
213        self.set_position(pos + n as u64);
214        BufResult(Ok(n), buf)
215    }
216
217    #[inline]
218    async fn read_vectored<T: IoVectoredBufMut>(&mut self, buf: T) -> BufResult<usize, T> {
219        let pos = self.position();
220        let (n, buf) = buf_try!(self.get_ref().read_vectored_at(buf, pos).await);
221        self.set_position(pos + n as u64);
222        BufResult(Ok(n), buf)
223    }
224}
compio_io/read/mod.rs

compio_io/read/
mod.rs
