[−][src]Struct tokio::io::BufReader
The BufReader
struct adds buffering to any reader.
It can be excessively inefficient to work directly with a AsyncRead
instance. A BufReader
performs large, infrequent reads on the underlying
AsyncRead
and maintains an in-memory buffer of the results.
BufReader
can improve the speed of programs that make small and
repeated read calls to the same file or network socket. It does not
help when reading very large amounts at once, or reading just one or a few
times. It also provides no advantage when reading from a source that is
already in memory, like a Vec<u8>
.
When the BufReader
is dropped, the contents of its buffer will be
discarded. Creating multiple instances of a BufReader
on the same
stream can cause data loss.
Methods
impl<R> BufReader<R> where
R: AsyncRead,
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R: AsyncRead,
pub fn new(inner: R) -> BufReader<R>
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Creates a new BufReader
with a default buffer capacity. The default is currently 8 KB,
but may change in the future.
pub fn with_capacity(capacity: usize, inner: R) -> BufReader<R>
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Creates a new BufReader
with the specified buffer capacity.
ⓘImportant traits for &'_ mut Fpub fn get_ref(&self) -> &R
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Gets a reference to the underlying reader.
It is inadvisable to directly read from the underlying reader.
ⓘImportant traits for &'_ mut Fpub fn get_mut(&mut self) -> &mut R
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Gets a mutable reference to the underlying reader.
It is inadvisable to directly read from the underlying reader.
ⓘImportant traits for Pin<P>pub fn get_pin_mut(self: Pin<&mut BufReader<R>>) -> Pin<&mut R>
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Gets a pinned mutable reference to the underlying reader.
It is inadvisable to directly read from the underlying reader.
pub fn into_inner(self) -> R
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Consumes this BufWriter
, returning the underlying reader.
Note that any leftover data in the internal buffer is lost.
pub fn buffer(&self) -> &[u8]
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Returns a reference to the internally buffered data.
Unlike fill_buf
, this will not attempt to fill the buffer if it is empty.
Trait Implementations
impl<R> AsyncRead for BufReader<R> where
R: AsyncRead,
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R: AsyncRead,
fn poll_read(
self: Pin<&mut BufReader<R>>,
cx: &mut Context,
buf: &mut [u8]
) -> Poll<Result<usize, Error>>
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self: Pin<&mut BufReader<R>>,
cx: &mut Context,
buf: &mut [u8]
) -> Poll<Result<usize, Error>>
unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [u8]) -> bool
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fn poll_read_buf<B>(
self: Pin<&mut Self>,
cx: &mut Context,
buf: &mut B
) -> Poll<Result<usize, Error>> where
B: BufMut,
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self: Pin<&mut Self>,
cx: &mut Context,
buf: &mut B
) -> Poll<Result<usize, Error>> where
B: BufMut,
Pull some bytes from this source into the specified BufMut
, returning how many bytes were read. Read more
impl<R> Debug for BufReader<R> where
R: AsyncRead + Debug,
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R: AsyncRead + Debug,
impl<R> AsyncBufRead for BufReader<R> where
R: AsyncRead,
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R: AsyncRead,
Auto Trait Implementations
impl<R> Send for BufReader<R> where
R: Send,
R: Send,
impl<R> Unpin for BufReader<R> where
R: Unpin,
R: Unpin,
impl<R> Sync for BufReader<R> where
R: Sync,
R: Sync,
impl<R> UnwindSafe for BufReader<R> where
R: UnwindSafe,
R: UnwindSafe,
impl<R> RefUnwindSafe for BufReader<R> where
R: RefUnwindSafe,
R: RefUnwindSafe,
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<R> AsyncBufReadExt for R where
R: AsyncBufRead + ?Sized,
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R: AsyncBufRead + ?Sized,
fn read_until(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>
) -> ReadUntil<'a, Self> where
Self: Unpin,
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&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>
) -> ReadUntil<'a, Self> where
Self: Unpin,
Creates a future which will read all the bytes associated with this I/O object into buf
until the delimiter byte
or EOF is reached. This method is the async equivalent to BufRead::read_until
. Read more
fn read_line(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self> where
Self: Unpin,
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Self: Unpin,
Creates a future which will read all the bytes associated with this I/O object into buf
until a newline (the 0xA byte) or EOF is reached, This method is the async equivalent to BufRead::read_line
. Read more
fn lines(self) -> Lines<Self>
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Returns a stream over the lines of this reader. This method is the async equivalent to BufRead::lines
. Read more
impl<R> AsyncReadExt for R where
R: AsyncRead + ?Sized,
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R: AsyncRead + ?Sized,
fn chain<R>(self, next: R) -> Chain<Self, R> where
R: AsyncRead,
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R: AsyncRead,
Creates an adaptor which will chain this stream with another. Read more
fn copy<W>(&'a mut self, dst: &'a mut W) -> Copy<'a, Self, W> where
Self: Unpin,
W: AsyncWrite + Unpin + ?Sized,
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Self: Unpin,
W: AsyncWrite + Unpin + ?Sized,
Copy all data from self
into the provided AsyncWrite
. Read more
fn read(&'a mut self, dst: &'a mut [u8]) -> Read<'a, Self> where
Self: Unpin,
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Self: Unpin,
Read data into the provided buffer. Read more
fn read_exact(&'a mut self, dst: &'a mut [u8]) -> ReadExact<'a, Self> where
Self: Unpin,
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Self: Unpin,
Read exactly the amount of data needed to fill the provided buffer.
fn read_to_end(&'a mut self, dst: &'a mut Vec<u8>) -> ReadToEnd<'a, Self> where
Self: Unpin,
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Self: Unpin,
Read all bytes until EOF in this source, placing them into dst
. Read more
fn read_to_string(&'a mut self, dst: &'a mut String) -> ReadToString<'a, Self> where
Self: Unpin,
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Self: Unpin,
Read all bytes until EOF in this source, placing them into dst
. Read more
fn take(self, limit: u64) -> Take<Self>
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Creates an AsyncRead adapter which will read at most limit
bytes from the underlying reader. Read more