Struct tokio::io::BufWriter [−][src]
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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Gets a reference to the underlying writer.
pub fn get_mut(&mut self) -> &mut Wⓘ
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Gets a mutable reference to the underlying writer.
It is inadvisable to directly write to the underlying writer.
pub fn get_pin_mut(self: Pin<&mut Self>) -> Pin<&mut W>ⓘ
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Gets a pinned mutable reference to the underlying writer.
It is inadvisable to directly write to the underlying writer.
pub fn into_inner(self) -> W
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Consumes this BufWriter
, returning the underlying writer.
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.
Trait Implementations
impl<W: AsyncWrite + 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: AsyncWrite + AsyncRead> AsyncRead for BufWriter<W>
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fn poll_read(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>
) -> Poll<Result<()>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut ReadBuf<'_>
) -> Poll<Result<()>>
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_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
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fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
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fn poll_write_vectored(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>
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self: Pin<&mut Self>,
cx: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize, Error>>
fn is_write_vectored(&self) -> bool
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impl<W: Debug> Debug for BufWriter<W>
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impl<RW> From<BufWriter<BufReader<RW>>> for BufStream<RW>
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impl<'__pin, W> Unpin for BufWriter<W> where
__Origin<'__pin, W>: Unpin,
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__Origin<'__pin, W>: Unpin,
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<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,
pub 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.
pub 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>,