[−][src]Struct futures_util::io::BufWriter
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
impl<W: AsyncWrite> BufWriter<W>
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pub fn new(inner: W) -> Self
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Creates a new BufWriter
with a default buffer capacity. The default is currently 8 KB,
but may change in the future.
pub fn with_capacity(cap: usize, inner: W) -> Self
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Creates a new BufWriter
with the specified buffer capacity.
pub fn get_ref(&self) -> &Wⓘ
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Acquires a reference to the underlying sink or stream that this combinator is pulling from.
pub fn get_mut(&mut self) -> &mut Wⓘ
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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.
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut W>ⓘ
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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.
pub fn into_inner(self) -> W
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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.
pub fn buffer(&self) -> &[u8]ⓘ
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Returns a reference to the internally buffered data.
Trait Implementations
impl<W: AsyncBufRead> AsyncBufRead for BufWriter<W>
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fn poll_fill_buf(
self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<&[u8]>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>
) -> Poll<Result<&[u8]>>
fn consume(self: Pin<&mut Self>, amt: usize)
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impl<W: AsyncRead> AsyncRead for BufWriter<W>
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fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8]
) -> Poll<Result<usize>>
fn poll_read_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &mut [IoSliceMut<'_>]
) -> Poll<Result<usize>>
impl<W: AsyncWrite + AsyncSeek> AsyncSeek for BufWriter<W>
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fn poll_seek(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
pos: SeekFrom
) -> Poll<Result<u64>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
pos: SeekFrom
) -> Poll<Result<u64>>
Seek to the offset, in bytes, in the underlying writer.
Seeking always writes out the internal buffer before seeking.
impl<W: AsyncWrite> AsyncWrite for BufWriter<W>
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fn poll_write(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
fn poll_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize>>
fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
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fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
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impl<W: Debug> Debug for BufWriter<W>
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impl<W> PinnedDrop for BufWriter<W>
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impl<'pin, W> Unpin for BufWriter<W> where
__BufWriter<'pin, W>: Unpin,
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__BufWriter<'pin, W>: Unpin,
impl<W> UnsafeUnpin for BufWriter<W>
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Auto Trait Implementations
impl<W> RefUnwindSafe for BufWriter<W> where
W: RefUnwindSafe,
W: RefUnwindSafe,
impl<W> Send for BufWriter<W> where
W: Send,
W: Send,
impl<W> Sync for BufWriter<W> where
W: Sync,
W: Sync,
impl<W> UnwindSafe for BufWriter<W> where
W: UnwindSafe,
W: UnwindSafe,
Blanket Implementations
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>(
&'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,
fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self>ⓘ where
Self: Unpin,
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Self: Unpin,
fn lines(self) -> Lines<Self> where
Self: Sized,
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Self: Sized,
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
Self: Sized,
R: AsyncRead,
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Self: Sized,
R: AsyncRead,
fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> Read<'a, Self>ⓘ where
Self: Unpin,
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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,
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&'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>;
Self: Unpin,
fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExact<'a, Self>ⓘ where
Self: Unpin,
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Self: Unpin,
fn read_to_end<'a>(&'a mut self, buf: &'a mut Vec<u8>) -> ReadToEnd<'a, Self>ⓘ where
Self: Unpin,
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Self: Unpin,
fn read_to_string<'a>(
&'a mut self,
buf: &'a mut String
) -> ReadToString<'a, Self>ⓘNotable traits for ReadToString<'_, A>
impl<A: ?Sized, '_> Future for ReadToString<'_, A> where
A: AsyncRead + Unpin, type Output = Result<usize>;
where
Self: Unpin,
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&'a mut self,
buf: &'a mut String
) -> ReadToString<'a, Self>ⓘ
Notable traits for ReadToString<'_, A>
impl<A: ?Sized, '_> Future for ReadToString<'_, A> where
A: AsyncRead + Unpin, type Output = Result<usize>;
Self: Unpin,
fn split(self) -> (ReadHalf<Self>, WriteHalf<Self>) where
Self: AsyncWrite + Sized,
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Self: AsyncWrite + Sized,
fn take(self, limit: u64) -> Take<Self> where
Self: Sized,
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Self: Sized,
impl<S> AsyncSeekExt for S where
S: AsyncSeek + ?Sized,
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S: AsyncSeek + ?Sized,
impl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
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W: AsyncWrite + ?Sized,
fn flush(&mut self) -> Flush<'_, Self>ⓘ where
Self: Unpin,
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Self: Unpin,
fn close(&mut self) -> Close<'_, Self>ⓘ where
Self: Unpin,
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Self: Unpin,
fn write<'a>(&'a mut self, buf: &'a [u8]) -> Write<'a, Self>ⓘ where
Self: Unpin,
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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,
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&'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>;
Self: Unpin,
fn write_all<'a>(&'a mut self, buf: &'a [u8]) -> WriteAll<'a, Self>ⓘ where
Self: Unpin,
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Self: Unpin,
fn into_sink<Item: AsRef<[u8]>>(self) -> IntoSink<Self, Item> where
Self: Sized,
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Self: Sized,
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,
fn borrow_mut(&mut self) -> &mut Tⓘ
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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>,