Struct futures_util::io::BufWriter
source · [−]pub struct BufWriter<W> { /* private fields */ }
Expand description
Wraps a writer and buffers its output.
It can be excessively inefficient to work directly with something that
implements AsyncWrite
. A BufWriter
keeps an in-memory buffer of data and
writes it to an underlying writer in large, infrequent batches.
BufWriter
can improve the speed of programs that make small and
repeated write calls to the same file or network socket. It does not
help when writing very large amounts at once, or writing just one or a few
times. It also provides no advantage when writing to a destination that is
in memory, like a Vec<u8>
.
When the BufWriter
is dropped, the contents of its buffer will be
discarded. Creating multiple instances of a BufWriter
on the same
stream can cause data loss. If you need to write out the contents of its
buffer, you must manually call flush before the writer is dropped.
Implementations
sourceimpl<W: AsyncWrite> BufWriter<W>
impl<W: AsyncWrite> BufWriter<W>
sourcepub fn new(inner: W) -> Self
pub fn new(inner: W) -> Self
Creates a new BufWriter
with a default buffer capacity. The default is currently 8 KB,
but may change in the future.
sourcepub fn with_capacity(cap: usize, inner: W) -> Self
pub fn with_capacity(cap: usize, inner: W) -> Self
Creates a new BufWriter
with the specified buffer capacity.
sourcepub fn get_ref(&self) -> &W
pub fn get_ref(&self) -> &W
Acquires a reference to the underlying sink or stream that this combinator is pulling from.
sourcepub fn get_mut(&mut self) -> &mut W
pub fn get_mut(&mut self) -> &mut W
Acquires a mutable reference to the underlying sink or stream that this combinator is pulling from.
Note that care must be taken to avoid tampering with the state of the sink or stream which may otherwise confuse this combinator.
sourcepub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut W>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut W>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
P: DerefMut,
<P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;
Acquires a pinned mutable reference to the underlying sink or stream that this combinator is pulling from.
Note that care must be taken to avoid tampering with the state of the sink or stream which may otherwise confuse this combinator.
sourcepub fn into_inner(self) -> W
pub fn into_inner(self) -> W
Consumes this combinator, returning the underlying sink or stream.
Note that this may discard intermediate state of this combinator, so care should be taken to avoid losing resources when this is called.
Trait Implementations
sourceimpl<W: AsyncBufRead> AsyncBufRead for BufWriter<W>
impl<W: AsyncBufRead> AsyncBufRead for BufWriter<W>
sourceimpl<W: AsyncRead> AsyncRead for BufWriter<W>
impl<W: AsyncRead> AsyncRead for BufWriter<W>
sourceimpl<W: AsyncWrite + AsyncSeek> AsyncSeek for BufWriter<W>
impl<W: AsyncWrite + AsyncSeek> AsyncSeek for BufWriter<W>
sourceimpl<W: AsyncWrite> AsyncWrite for BufWriter<W>
impl<W: AsyncWrite> AsyncWrite for BufWriter<W>
sourcefn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
Attempt to write bytes from buf
into the object. Read more
sourcefn poll_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize>>
fn poll_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize>>
Attempt to write bytes from bufs
into the object using vectored
IO operations. Read more
impl<'__pin, W> Unpin for BufWriter<W> where
__Origin<'__pin, W>: Unpin,
Auto Trait Implementations
impl<W> RefUnwindSafe for BufWriter<W> where
W: RefUnwindSafe,
impl<W> Send for BufWriter<W> where
W: Send,
impl<W> Sync for BufWriter<W> where
W: Sync,
impl<W> UnwindSafe for BufWriter<W> where
W: UnwindSafe,
Blanket Implementations
sourceimpl<R> AsyncBufReadExt for R where
R: AsyncBufRead + ?Sized,
impl<R> AsyncBufReadExt for R where
R: AsyncBufRead + ?Sized,
sourcefn fill_buf(&mut self) -> FillBuf<'_, Self>ⓘNotable traits for FillBuf<'a, R>impl<'a, R> Future for FillBuf<'a, R> where
R: AsyncBufRead + ?Sized + Unpin, type Output = Result<&'a [u8]>;
where
Self: Unpin,
fn fill_buf(&mut self) -> FillBuf<'_, Self>ⓘNotable traits for FillBuf<'a, R>impl<'a, R> Future for FillBuf<'a, R> where
R: AsyncBufRead + ?Sized + Unpin, type Output = Result<&'a [u8]>;
where
Self: Unpin,
R: AsyncBufRead + ?Sized + Unpin, type Output = Result<&'a [u8]>;
Creates a future which will wait for a non-empty buffer to be available from this I/O object or EOF to be reached. Read more
sourcefn consume_unpin(&mut self, amt: usize) where
Self: Unpin,
fn consume_unpin(&mut self, amt: usize) where
Self: Unpin,
A convenience for calling AsyncBufRead::consume
on Unpin
IO types. Read more
sourcefn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>
) -> ReadUntil<'a, Self>ⓘNotable traits for ReadUntil<'_, R>impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadUntil<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>
) -> ReadUntil<'a, Self>ⓘNotable traits for ReadUntil<'_, R>impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadUntil<'_, R> type Output = Result<usize>;
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
sourcefn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self>ⓘNotable traits for ReadLine<'_, R>impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadLine<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self>ⓘNotable traits for ReadLine<'_, R>impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadLine<'_, R> type Output = Result<usize>;
where
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
sourceimpl<R> AsyncReadExt for R where
R: AsyncRead + ?Sized,
impl<R> AsyncReadExt for R where
R: AsyncRead + ?Sized,
sourcefn chain<R>(self, next: R) -> Chain<Self, R> where
Self: Sized,
R: AsyncRead,
fn chain<R>(self, next: R) -> Chain<Self, R> where
Self: Sized,
R: AsyncRead,
Creates an adaptor which will chain this stream with another. Read more
sourcefn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self>ⓘNotable traits for Read<'_, R>impl<R: AsyncRead + ?Sized + Unpin> Future for Read<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self>ⓘNotable traits for Read<'_, R>impl<R: AsyncRead + ?Sized + Unpin> Future for Read<'_, R> type Output = Result<usize>;
where
Self: Unpin,
Tries to read some bytes directly into the given buf
in asynchronous
manner, returning a future type. Read more
sourcefn read_vectored<'a>(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>]
) -> ReadVectored<'a, Self>ⓘNotable traits for ReadVectored<'_, R>impl<R: AsyncRead + ?Sized + Unpin> Future for ReadVectored<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_vectored<'a>(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>]
) -> ReadVectored<'a, Self>ⓘNotable traits for ReadVectored<'_, R>impl<R: AsyncRead + ?Sized + Unpin> Future for ReadVectored<'_, R> type Output = Result<usize>;
where
Self: Unpin,
Creates a future which will read from the AsyncRead
into bufs
using vectored
IO operations. Read more
sourcefn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self>ⓘNotable traits for ReadExact<'_, R>impl<R: AsyncRead + ?Sized + Unpin> Future for ReadExact<'_, R> type Output = Result<()>;
where
Self: Unpin,
fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self>ⓘNotable traits for ReadExact<'_, R>impl<R: AsyncRead + ?Sized + Unpin> Future for ReadExact<'_, R> type Output = Result<()>;
where
Self: Unpin,
Creates a future which will read exactly enough bytes to fill buf
,
returning an error if end of file (EOF) is hit sooner. Read more
sourcefn read_to_end<'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self>ⓘNotable traits for ReadToEnd<'_, A>impl<A> Future for ReadToEnd<'_, A> where
A: AsyncRead + ?Sized + Unpin, type Output = Result<usize>;
where
Self: Unpin,
fn read_to_end<'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self>ⓘNotable traits for ReadToEnd<'_, A>impl<A> Future for ReadToEnd<'_, A> where
A: AsyncRead + ?Sized + Unpin, type Output = Result<usize>;
where
Self: Unpin,
A: AsyncRead + ?Sized + Unpin, type Output = Result<usize>;
Creates a future which will read all the bytes from this AsyncRead
. Read more
sourcefn read_to_string<'a>(
&'a mut self,
buf: &'a mut String
) -> ReadToString<'a, Self>ⓘNotable traits for ReadToString<'_, A>impl<A> Future for ReadToString<'_, A> where
A: AsyncRead + ?Sized + Unpin, type Output = Result<usize>;
where
Self: Unpin,
fn read_to_string<'a>(
&'a mut self,
buf: &'a mut String
) -> ReadToString<'a, Self>ⓘNotable traits for ReadToString<'_, A>impl<A> Future for ReadToString<'_, A> where
A: AsyncRead + ?Sized + Unpin, type Output = Result<usize>;
where
Self: Unpin,
A: AsyncRead + ?Sized + Unpin, type Output = Result<usize>;
Creates a future which will read all the bytes from this AsyncRead
. Read more
sourceimpl<S> AsyncSeekExt for S where
S: AsyncSeek + ?Sized,
impl<S> AsyncSeekExt for S where
S: AsyncSeek + ?Sized,
sourcefn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>ⓘNotable traits for Seek<'_, S>impl<S: AsyncSeek + ?Sized + Unpin> Future for Seek<'_, S> type Output = Result<u64>;
where
Self: Unpin,
fn seek(&mut self, pos: SeekFrom) -> Seek<'_, Self>ⓘNotable traits for Seek<'_, S>impl<S: AsyncSeek + ?Sized + Unpin> Future for Seek<'_, S> type Output = Result<u64>;
where
Self: Unpin,
Creates a future which will seek an IO object, and then yield the new position in the object and the object itself. Read more
sourceimpl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
impl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
sourcefn flush(&mut self) -> Flush<'_, Self>ⓘNotable traits for Flush<'_, W>impl<W> Future for Flush<'_, W> where
W: AsyncWrite + ?Sized + Unpin, type Output = Result<()>;
where
Self: Unpin,
fn flush(&mut self) -> Flush<'_, Self>ⓘNotable traits for Flush<'_, W>impl<W> Future for Flush<'_, W> where
W: AsyncWrite + ?Sized + Unpin, type Output = Result<()>;
where
Self: Unpin,
W: AsyncWrite + ?Sized + Unpin, type Output = Result<()>;
Creates a future which will entirely flush this AsyncWrite
. Read more
sourcefn close(&mut self) -> Close<'_, Self>ⓘNotable traits for Close<'_, W>impl<W: AsyncWrite + ?Sized + Unpin> Future for Close<'_, W> type Output = Result<()>;
where
Self: Unpin,
fn close(&mut self) -> Close<'_, Self>ⓘNotable traits for Close<'_, W>impl<W: AsyncWrite + ?Sized + Unpin> Future for Close<'_, W> type Output = Result<()>;
where
Self: Unpin,
Creates a future which will entirely close this AsyncWrite
.
sourcefn write<'a>(&'a mut self, buf: &'a [u8]) -> Write<'a, Self>ⓘNotable traits for Write<'_, W>impl<W: AsyncWrite + ?Sized + Unpin> Future for Write<'_, W> type Output = Result<usize>;
where
Self: Unpin,
fn write<'a>(&'a mut self, buf: &'a [u8]) -> Write<'a, Self>ⓘNotable traits for Write<'_, W>impl<W: AsyncWrite + ?Sized + Unpin> Future for Write<'_, W> type Output = Result<usize>;
where
Self: Unpin,
Creates a future which will write bytes from buf
into the object. Read more
sourcefn write_vectored<'a>(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectored<'a, Self>ⓘNotable traits for WriteVectored<'_, W>impl<W: AsyncWrite + ?Sized + Unpin> Future for WriteVectored<'_, W> type Output = Result<usize>;
where
Self: Unpin,
fn write_vectored<'a>(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectored<'a, Self>ⓘNotable traits for WriteVectored<'_, W>impl<W: AsyncWrite + ?Sized + Unpin> Future for WriteVectored<'_, W> type Output = Result<usize>;
where
Self: Unpin,
Creates a future which will write bytes from bufs
into the object using vectored
IO operations. Read more
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcepub fn borrow_mut(&mut self) -> &mut T
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more