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_mut(&mut self) -> &mut W
pub fn get_mut(&mut self) -> &mut W
Gets a mutable reference to the underlying writer.
It is inadvisable to directly write to the underlying writer.
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;
Gets a pinned mutable reference to the underlying writer.
It is inadvisable to directly write to the underlying writer.
sourcepub fn into_inner(self) -> W
pub fn into_inner(self) -> W
Consumes this BufWriter
, returning the underlying writer.
Note that any leftover data in the internal buffer is lost.
Trait Implementations
sourceimpl<W: AsyncWrite + AsyncBufRead> AsyncBufRead for BufWriter<W>
impl<W: AsyncWrite + AsyncBufRead> AsyncBufRead for BufWriter<W>
sourceimpl<W: AsyncWrite + AsyncRead> AsyncRead for BufWriter<W>
impl<W: AsyncWrite + AsyncRead> AsyncRead for BufWriter<W>
sourceimpl<W: AsyncWrite + AsyncSeek> AsyncSeek for BufWriter<W>
impl<W: AsyncWrite + AsyncSeek> AsyncSeek for BufWriter<W>
Seek to the offset, in bytes, in the underlying writer.
Seeking always writes out the internal buffer before seeking.
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>>
Like poll_write
, except that it writes from a slice of buffers. Read more
sourcefn is_write_vectored(&self) -> bool
fn is_write_vectored(&self) -> bool
Determines if this writer has an efficient poll_write_vectored
implementation. 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<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more