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@ -27,87 +27,100 @@ cfg_if! {
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}
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extension_trait! {
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/// Allows reading from a byte stream.
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///
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/// This trait is a re-export of [`futures::io::AsyncRead`] and is an async version of
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/// [`std::io::Read`].
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///
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/// Methods other than [`poll_read`] and [`poll_read_vectored`] do not really exist in the
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/// trait itself, but they become available when the prelude is imported:
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///
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/// ```
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/// # #[allow(unused_imports)]
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/// use async_std::prelude::*;
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/// ```
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///
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/// [`std::io::Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
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/// [`futures::io::AsyncRead`]:
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/// https://docs.rs/futures-preview/0.3.0-alpha.17/futures/io/trait.AsyncRead.html
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/// [`poll_read`]: #tymethod.poll_read
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/// [`poll_read_vectored`]: #method.poll_read_vectored
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#[doc = r#"
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Allows reading from a byte stream.
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This trait is a re-export of [`futures::io::AsyncRead`] and is an async version of
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[`std::io::Read`].
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Methods other than [`poll_read`] and [`poll_read_vectored`] do not really exist in the
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trait itself, but they become available when the prelude is imported:
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```
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# #[allow(unused_imports)]
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use async_std::prelude::*;
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```
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[`std::io::Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
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[`futures::io::AsyncRead`]:
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https://docs.rs/futures-preview/0.3.0-alpha.17/futures/io/trait.AsyncRead.html
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[`poll_read`]: #tymethod.poll_read
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[`poll_read_vectored`]: #method.poll_read_vectored
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"#]
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pub trait Read [ReadExt: futures_io::AsyncRead] {
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/// Attempt to read from the `AsyncRead` into `buf`.
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#[doc = r#"
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Attempt to read from the `AsyncRead` into `buf`.
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"#]
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fn poll_read(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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buf: &mut [u8],
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) -> Poll<io::Result<usize>>;
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/// Attempt to read from the `AsyncRead` into `bufs` using vectored IO operations.
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#[doc = r#"
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Attempt to read from the `AsyncRead` into `bufs` using vectored IO operations.
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"#]
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fn poll_read_vectored(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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bufs: &mut [IoSliceMut<'_>],
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) -> Poll<io::Result<usize>> {
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unreachable!()
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unreachable!("this impl only appears in the rendered docs")
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}
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/// Reads some bytes from the byte stream.
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///
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/// Returns the number of bytes read from the start of the buffer.
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///
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/// If the return value is `Ok(n)`, then it must be guaranteed that
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/// `0 <= n <= buf.len()`. A nonzero `n` value indicates that the buffer has been
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/// filled in with `n` bytes of data. If `n` is `0`, then it can indicate one of two
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/// scenarios:
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///
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/// 1. This reader has reached its "end of file" and will likely no longer be able to
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/// produce bytes. Note that this does not mean that the reader will always no
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/// longer be able to produce bytes.
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/// 2. The buffer specified was 0 bytes in length.
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///
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|
/// # Examples
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///
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|
/// ```no_run
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|
/// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
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/// #
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|
/// use async_std::fs::File;
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|
/// use async_std::prelude::*;
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///
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/// let mut file = File::open("a.txt").await?;
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///
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/// let mut buf = vec![0; 1024];
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/// let n = file.read(&mut buf).await?;
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/// #
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|
/// # Ok(()) }) }
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|
/// ```
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|
fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> impl Future<Output = io::Result<usize>> + 'a [ReadFuture<'a, Self>]
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|
|
#[doc = r#"
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|
Reads some bytes from the byte stream.
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|
Returns the number of bytes read from the start of the buffer.
|
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|
If the return value is `Ok(n)`, then it must be guaranteed that
|
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|
|
`0 <= n <= buf.len()`. A nonzero `n` value indicates that the buffer has been
|
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|
|
filled in with `n` bytes of data. If `n` is `0`, then it can indicate one of two
|
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|
|
scenarios:
|
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|
|
|
|
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|
|
1. This reader has reached its "end of file" and will likely no longer be able to
|
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|
|
produce bytes. Note that this does not mean that the reader will always no
|
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|
|
|
longer be able to produce bytes.
|
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|
2. The buffer specified was 0 bytes in length.
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|
|
# Examples
|
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|
```no_run
|
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|
|
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
|
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|
|
#
|
|
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|
|
use async_std::fs::File;
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|
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|
|
use async_std::prelude::*;
|
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|
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|
|
|
|
|
|
let mut file = File::open("a.txt").await?;
|
|
|
|
|
|
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|
|
let mut buf = vec![0; 1024];
|
|
|
|
|
let n = file.read(&mut buf).await?;
|
|
|
|
|
#
|
|
|
|
|
# Ok(()) }) }
|
|
|
|
|
```
|
|
|
|
|
"#]
|
|
|
|
|
fn read<'a>(
|
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|
|
&'a mut self,
|
|
|
|
|
buf: &'a mut [u8],
|
|
|
|
|
) -> impl Future<Output = io::Result<usize>> + 'a [ReadFuture<'a, Self>]
|
|
|
|
|
where
|
|
|
|
|
Self: Unpin
|
|
|
|
|
{
|
|
|
|
|
ReadFuture { reader: self, buf }
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Like [`read`], except that it reads into a slice of buffers.
|
|
|
|
|
///
|
|
|
|
|
/// Data is copied to fill each buffer in order, with the final buffer written to
|
|
|
|
|
/// possibly being only partially filled. This method must behave as a single call to
|
|
|
|
|
/// [`read`] with the buffers concatenated would.
|
|
|
|
|
///
|
|
|
|
|
/// The default implementation calls [`read`] with either the first nonempty buffer
|
|
|
|
|
/// provided, or an empty one if none exists.
|
|
|
|
|
///
|
|
|
|
|
/// [`read`]: #tymethod.read
|
|
|
|
|
#[doc = r#"
|
|
|
|
|
Like [`read`], except that it reads into a slice of buffers.
|
|
|
|
|
|
|
|
|
|
Data is copied to fill each buffer in order, with the final buffer written to
|
|
|
|
|
possibly being only partially filled. This method must behave as a single call to
|
|
|
|
|
[`read`] with the buffers concatenated would.
|
|
|
|
|
|
|
|
|
|
The default implementation calls [`read`] with either the first nonempty buffer
|
|
|
|
|
provided, or an empty one if none exists.
|
|
|
|
|
|
|
|
|
|
[`read`]: #tymethod.read
|
|
|
|
|
"#]
|
|
|
|
|
fn read_vectored<'a>(
|
|
|
|
|
&'a mut self,
|
|
|
|
|
bufs: &'a mut [IoSliceMut<'a>],
|
|
|
|
@ -118,31 +131,33 @@ extension_trait! {
|
|
|
|
|
ReadVectoredFuture { reader: self, bufs }
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reads all bytes from the byte stream.
|
|
|
|
|
///
|
|
|
|
|
/// All bytes read from this stream will be appended to the specified buffer `buf`.
|
|
|
|
|
/// This function will continuously call [`read`] to append more data to `buf` until
|
|
|
|
|
/// [`read`] returns either `Ok(0)` or an error.
|
|
|
|
|
///
|
|
|
|
|
/// If successful, this function will return the total number of bytes read.
|
|
|
|
|
///
|
|
|
|
|
/// [`read`]: #tymethod.read
|
|
|
|
|
///
|
|
|
|
|
/// # Examples
|
|
|
|
|
///
|
|
|
|
|
/// ```no_run
|
|
|
|
|
/// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
|
|
|
|
|
/// #
|
|
|
|
|
/// use async_std::fs::File;
|
|
|
|
|
/// use async_std::prelude::*;
|
|
|
|
|
///
|
|
|
|
|
/// let mut file = File::open("a.txt").await?;
|
|
|
|
|
///
|
|
|
|
|
/// let mut buf = Vec::new();
|
|
|
|
|
/// file.read_to_end(&mut buf).await?;
|
|
|
|
|
/// #
|
|
|
|
|
/// # Ok(()) }) }
|
|
|
|
|
/// ```
|
|
|
|
|
#[doc = r#"
|
|
|
|
|
Reads all bytes from the byte stream.
|
|
|
|
|
|
|
|
|
|
All bytes read from this stream will be appended to the specified buffer `buf`.
|
|
|
|
|
This function will continuously call [`read`] to append more data to `buf` until
|
|
|
|
|
[`read`] returns either `Ok(0)` or an error.
|
|
|
|
|
|
|
|
|
|
If successful, this function will return the total number of bytes read.
|
|
|
|
|
|
|
|
|
|
[`read`]: #tymethod.read
|
|
|
|
|
|
|
|
|
|
# Examples
|
|
|
|
|
|
|
|
|
|
```no_run
|
|
|
|
|
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
|
|
|
|
|
#
|
|
|
|
|
use async_std::fs::File;
|
|
|
|
|
use async_std::prelude::*;
|
|
|
|
|
|
|
|
|
|
let mut file = File::open("a.txt").await?;
|
|
|
|
|
|
|
|
|
|
let mut buf = Vec::new();
|
|
|
|
|
file.read_to_end(&mut buf).await?;
|
|
|
|
|
#
|
|
|
|
|
# Ok(()) }) }
|
|
|
|
|
```
|
|
|
|
|
"#]
|
|
|
|
|
fn read_to_end<'a>(
|
|
|
|
|
&'a mut self,
|
|
|
|
|
buf: &'a mut Vec<u8>,
|
|
|
|
@ -158,28 +173,30 @@ extension_trait! {
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reads all bytes from the byte stream and appends them into a string.
|
|
|
|
|
///
|
|
|
|
|
/// If successful, this function will return the number of bytes read.
|
|
|
|
|
///
|
|
|
|
|
/// If the data in this stream is not valid UTF-8 then an error will be returned and
|
|
|
|
|
/// `buf` will be left unmodified.
|
|
|
|
|
///
|
|
|
|
|
/// # Examples
|
|
|
|
|
///
|
|
|
|
|
/// ```no_run
|
|
|
|
|
/// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
|
|
|
|
|
/// #
|
|
|
|
|
/// use async_std::fs::File;
|
|
|
|
|
/// use async_std::prelude::*;
|
|
|
|
|
///
|
|
|
|
|
/// let mut file = File::open("a.txt").await?;
|
|
|
|
|
///
|
|
|
|
|
/// let mut buf = String::new();
|
|
|
|
|
/// file.read_to_string(&mut buf).await?;
|
|
|
|
|
/// #
|
|
|
|
|
/// # Ok(()) }) }
|
|
|
|
|
/// ```
|
|
|
|
|
#[doc = r#"
|
|
|
|
|
Reads all bytes from the byte stream and appends them into a string.
|
|
|
|
|
|
|
|
|
|
If successful, this function will return the number of bytes read.
|
|
|
|
|
|
|
|
|
|
If the data in this stream is not valid UTF-8 then an error will be returned and
|
|
|
|
|
`buf` will be left unmodified.
|
|
|
|
|
|
|
|
|
|
# Examples
|
|
|
|
|
|
|
|
|
|
```no_run
|
|
|
|
|
# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
|
|
|
|
|
#
|
|
|
|
|
use async_std::fs::File;
|
|
|
|
|
use async_std::prelude::*;
|
|
|
|
|
|
|
|
|
|
let mut file = File::open("a.txt").await?;
|
|
|
|
|
|
|
|
|
|
let mut buf = String::new();
|
|
|
|
|
file.read_to_string(&mut buf).await?;
|
|
|
|
|
#
|
|
|
|
|
# Ok(()) }) }
|
|
|
|
|
```
|
|
|
|
|
"#]
|
|
|
|
|
fn read_to_string<'a>(
|
|
|
|
|
&'a mut self,
|
|
|
|
|
buf: &'a mut String,
|
|
|
|
@ -196,44 +213,49 @@ extension_trait! {
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/// Reads the exact number of bytes required to fill `buf`.
|
|
|
|
|
///
|
|
|
|
|
/// This function reads as many bytes as necessary to completely fill the specified
|
|
|
|
|
/// buffer `buf`.
|
|
|
|
|
///
|
|
|
|
|
/// No guarantees are provided about the contents of `buf` when this function is
|
|
|
|
|
/// called, implementations cannot rely on any property of the contents of `buf` being
|
|
|
|
|
/// true. It is recommended that implementations only write data to `buf` instead of
|
|
|
|
|
/// reading its contents.
|
|
|
|
|
///
|
|
|
|
|
/// If this function encounters an "end of file" before completely filling the buffer,
|
|
|
|
|
/// it returns an error of the kind [`ErrorKind::UnexpectedEof`]. The contents of
|
|
|
|
|
/// `buf` are unspecified in this case.
|
|
|
|
|
///
|
|
|
|
|
/// If any other read error is encountered then this function immediately returns. The
|
|
|
|
|
/// contents of `buf` are unspecified in this case.
|
|
|
|
|
///
|
|
|
|
|
/// If this function returns an error, it is unspecified how many bytes it has read,
|
|
|
|
|
/// but it will never read more than would be necessary to completely fill the buffer.
|
|
|
|
|
///
|
|
|
|
|
/// [`ErrorKind::UnexpectedEof`]: enum.ErrorKind.html#variant.UnexpectedEof
|
|
|
|
|
///
|
|
|
|
|
/// # Examples
|
|
|
|
|
///
|
|
|
|
|
/// ```no_run
|
|
|
|
|
/// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
|
|
|
|
|
/// #
|
|
|
|
|
/// use async_std::fs::File;
|
|
|
|
|
/// use async_std::prelude::*;
|
|
|
|
|
///
|
|
|
|
|
/// let mut file = File::open("a.txt").await?;
|
|
|
|
|
///
|
|
|
|
|
/// let mut buf = vec![0; 10];
|
|
|
|
|
/// file.read_exact(&mut buf).await?;
|
|
|
|
|
/// #
|
|
|
|
|
/// # Ok(()) }) }
|
|
|
|
|
/// ```
|
|
|
|
|
fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> impl Future<Output = io::Result<()>> + 'a [ReadExactFuture<'a, Self>]
|
|
|
|
|
#[doc = r#"
|
|
|
|
|
Reads the exact number of bytes required to fill `buf`.
|
|
|
|
|
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This function reads as many bytes as necessary to completely fill the specified
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buffer `buf`.
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No guarantees are provided about the contents of `buf` when this function is
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called, implementations cannot rely on any property of the contents of `buf` being
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true. It is recommended that implementations only write data to `buf` instead of
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reading its contents.
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If this function encounters an "end of file" before completely filling the buffer,
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it returns an error of the kind [`ErrorKind::UnexpectedEof`]. The contents of
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`buf` are unspecified in this case.
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If any other read error is encountered then this function immediately returns. The
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contents of `buf` are unspecified in this case.
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If this function returns an error, it is unspecified how many bytes it has read,
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but it will never read more than would be necessary to completely fill the buffer.
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[`ErrorKind::UnexpectedEof`]: enum.ErrorKind.html#variant.UnexpectedEof
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# Examples
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```no_run
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# fn main() -> std::io::Result<()> { async_std::task::block_on(async {
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#
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use async_std::fs::File;
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use async_std::prelude::*;
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let mut file = File::open("a.txt").await?;
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let mut buf = vec![0; 10];
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file.read_exact(&mut buf).await?;
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#
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# Ok(()) }) }
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```
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"#]
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fn read_exact<'a>(
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|
&'a mut self,
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|
buf: &'a mut [u8],
|
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|
) -> impl Future<Output = io::Result<()>> + 'a [ReadExactFuture<'a, Self>]
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|
where
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Self: Unpin,
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{
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|
@ -247,7 +269,7 @@ extension_trait! {
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cx: &mut Context<'_>,
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|
buf: &mut [u8],
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|
) -> Poll<io::Result<usize>> {
|
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|
unreachable!()
|
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|
unreachable!("this impl only appears in the rendered docs")
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|
}
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}
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|
@ -257,7 +279,7 @@ extension_trait! {
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|
cx: &mut Context<'_>,
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|
|
buf: &mut [u8],
|
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|
|
) -> Poll<io::Result<usize>> {
|
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|
|
|
unreachable!()
|
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|
|
|
unreachable!("this impl only appears in the rendered docs")
|
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|
|
}
|
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}
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@ -271,7 +293,7 @@ extension_trait! {
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|
cx: &mut Context<'_>,
|
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|
|
|
buf: &mut [u8],
|
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|
|
|
) -> Poll<io::Result<usize>> {
|
|
|
|
|
unreachable!()
|
|
|
|
|
unreachable!("this impl only appears in the rendered docs")
|
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|
|
|
}
|
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|
|
|
}
|
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|
@ -281,7 +303,7 @@ extension_trait! {
|
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|
|
cx: &mut Context<'_>,
|
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|
|
|
buf: &mut [u8],
|
|
|
|
|
) -> Poll<io::Result<usize>> {
|
|
|
|
|
unreachable!()
|
|
|
|
|
unreachable!("this impl only appears in the rendered docs")
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
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|