Struct otter_api_tests::io::LineWriter 1.0.0[−][src]
pub struct LineWriter<W> where
W: Write, { /* fields omitted */ }
Wraps a writer and buffers output to it, flushing whenever a newline
(0x0a
, '\n'
) is detected.
The BufWriter
struct wraps a writer and buffers its output.
But it only does this batched write when it goes out of scope, or when the
internal buffer is full. Sometimes, you’d prefer to write each line as it’s
completed, rather than the entire buffer at once. Enter LineWriter
. It
does exactly that.
Like BufWriter
, a LineWriter
’s buffer will also be flushed when the
LineWriter
goes out of scope or when its internal buffer is full.
If there’s still a partial line in the buffer when the LineWriter
is
dropped, it will flush those contents.
Examples
We can use LineWriter
to write one line at a time, significantly
reducing the number of actual writes to the file.
use std::fs::{self, File}; use std::io::prelude::*; use std::io::LineWriter; fn main() -> std::io::Result<()> { let road_not_taken = b"I shall be telling this with a sigh Somewhere ages and ages hence: Two roads diverged in a wood, and I - I took the one less traveled by, And that has made all the difference."; let file = File::create("poem.txt")?; let mut file = LineWriter::new(file); file.write_all(b"I shall be telling this with a sigh")?; // No bytes are written until a newline is encountered (or // the internal buffer is filled). assert_eq!(fs::read_to_string("poem.txt")?, ""); file.write_all(b"\n")?; assert_eq!( fs::read_to_string("poem.txt")?, "I shall be telling this with a sigh\n", ); // Write the rest of the poem. file.write_all(b"Somewhere ages and ages hence: Two roads diverged in a wood, and I - I took the one less traveled by, And that has made all the difference.")?; // The last line of the poem doesn't end in a newline, so // we have to flush or drop the `LineWriter` to finish // writing. file.flush()?; // Confirm the whole poem was written. assert_eq!(fs::read("poem.txt")?, &road_not_taken[..]); Ok(()) }
Implementations
impl<W> LineWriter<W> where
W: Write,
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W: Write,
pub fn new(inner: W) -> LineWriter<W>ⓘNotable traits for LineWriter<W>
impl<W> Write for LineWriter<W> where
W: Write,
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Notable traits for LineWriter<W>
impl<W> Write for LineWriter<W> where
W: Write,
Creates a new LineWriter
.
Examples
use std::fs::File; use std::io::LineWriter; fn main() -> std::io::Result<()> { let file = File::create("poem.txt")?; let file = LineWriter::new(file); Ok(()) }
pub fn with_capacity(capacity: usize, inner: W) -> LineWriter<W>ⓘNotable traits for LineWriter<W>
impl<W> Write for LineWriter<W> where
W: Write,
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Notable traits for LineWriter<W>
impl<W> Write for LineWriter<W> where
W: Write,
Creates a new LineWriter
with a specified capacity for the internal
buffer.
Examples
use std::fs::File; use std::io::LineWriter; fn main() -> std::io::Result<()> { let file = File::create("poem.txt")?; let file = LineWriter::with_capacity(100, file); Ok(()) }
pub fn get_ref(&self) -> &WⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
Gets a reference to the underlying writer.
Examples
use std::fs::File; use std::io::LineWriter; fn main() -> std::io::Result<()> { let file = File::create("poem.txt")?; let file = LineWriter::new(file); let reference = file.get_ref(); Ok(()) }
pub fn get_mut(&mut self) -> &mut WⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
Gets a mutable reference to the underlying writer.
Caution must be taken when calling methods on the mutable reference returned as extra writes could corrupt the output stream.
Examples
use std::fs::File; use std::io::LineWriter; fn main() -> std::io::Result<()> { let file = File::create("poem.txt")?; let mut file = LineWriter::new(file); // we can use reference just like file let reference = file.get_mut(); Ok(()) }
pub fn into_inner(self) -> Result<W, IntoInnerError<LineWriter<W>>>
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Unwraps this LineWriter
, returning the underlying writer.
The internal buffer is written out before returning the writer.
Errors
An Err
will be returned if an error occurs while flushing the buffer.
Examples
use std::fs::File; use std::io::LineWriter; fn main() -> std::io::Result<()> { let file = File::create("poem.txt")?; let writer: LineWriter<File> = LineWriter::new(file); let file: File = writer.into_inner()?; Ok(()) }
Trait Implementations
impl<W> Debug for LineWriter<W> where
W: Write + Debug,
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W: Write + Debug,
impl<W> Write for LineWriter<W> where
W: Write,
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W: Write,
pub fn write(&mut self, buf: &[u8]) -> Result<usize, Error>
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pub fn flush(&mut self) -> Result<(), Error>
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pub fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>
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pub fn is_write_vectored(&self) -> bool
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pub fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>
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pub fn write_all_vectored(
&mut self,
bufs: &mut [IoSlice<'_>]
) -> Result<(), Error>
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&mut self,
bufs: &mut [IoSlice<'_>]
) -> Result<(), Error>
pub fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result<(), Error>
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pub fn by_ref(&mut self) -> &mut SelfⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
Auto Trait Implementations
impl<W> RefUnwindSafe for LineWriter<W> where
W: RefUnwindSafe,
W: RefUnwindSafe,
impl<W> Send for LineWriter<W> where
W: Send,
W: Send,
impl<W> Sync for LineWriter<W> where
W: Sync,
W: Sync,
impl<W> Unpin for LineWriter<W> where
W: Unpin,
W: Unpin,
impl<W> UnwindSafe for LineWriter<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,
pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
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Notable traits for &'_ mut R
impl<'_, R> Read for &'_ mut R where
R: Read + ?Sized, impl<'_, W> Write for &'_ mut W where
W: Write + ?Sized, impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;
impl<T> Downcast for T where
T: Any,
T: Any,
pub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>ⓘNotable traits for Box<R, Global>
impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<F, A> Future for Box<F, A> where
A: Allocator + 'static,
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
A: Allocator,
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;
Notable traits for Box<R, Global>
impl<R> Read for Box<R, Global> where
R: Read + ?Sized, impl<W> Write for Box<W, Global> where
W: Write + ?Sized, impl<F, A> Future for Box<F, A> where
A: Allocator + 'static,
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<I, A> Iterator for Box<I, A> where
A: Allocator,
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;
pub fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
pub fn as_any(&self) -> &(dyn Any + 'static)
pub fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
impl<T> DowncastSync for T where
T: Any + Send + Sync,
T: Any + Send + Sync,
impl<A> DynCastExt for A
pub fn dyn_cast<T>(
self
) -> Result<<A as DynCastExtHelper<T>>::Target, <A as DynCastExtHelper<T>>::Source> where
T: ?Sized,
A: DynCastExtHelper<T>,
self
) -> Result<<A as DynCastExtHelper<T>>::Target, <A as DynCastExtHelper<T>>::Source> where
T: ?Sized,
A: DynCastExtHelper<T>,
pub fn dyn_upcast<T>(self) -> <A as DynCastExtAdvHelper<T, T>>::Target where
T: ?Sized,
A: DynCastExtAdvHelper<T, T, Source = <A as DynCastExtAdvHelper<T, T>>::Target>,
T: ?Sized,
A: DynCastExtAdvHelper<T, T, Source = <A as DynCastExtAdvHelper<T, T>>::Target>,
pub fn dyn_cast_adv<F, T>(
self
) -> Result<<A as DynCastExtAdvHelper<F, T>>::Target, <A as DynCastExtAdvHelper<F, T>>::Source> where
T: ?Sized,
A: DynCastExtAdvHelper<F, T>,
F: ?Sized,
self
) -> Result<<A as DynCastExtAdvHelper<F, T>>::Target, <A as DynCastExtAdvHelper<F, T>>::Source> where
T: ?Sized,
A: DynCastExtAdvHelper<F, T>,
F: ?Sized,
pub fn dyn_cast_with_config<C>(
self
) -> Result<<A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Target, <A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Source> where
C: DynCastConfig,
A: DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>,
self
) -> Result<<A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Target, <A as DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>>::Source> where
C: DynCastConfig,
A: DynCastExtAdvHelper<<C as DynCastConfig>::Source, <C as DynCastConfig>::Target>,
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>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,
pub fn vzip(self) -> V
impl<W> WriteBytesExt for W where
W: Write + ?Sized,
W: Write + ?Sized,
pub fn write_u8(&mut self, n: u8) -> Result<(), Error>
pub fn write_i8(&mut self, n: i8) -> Result<(), Error>
pub fn write_u16<T>(&mut self, n: u16) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_i16<T>(&mut self, n: i16) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_u24<T>(&mut self, n: u32) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_i24<T>(&mut self, n: i32) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_u32<T>(&mut self, n: u32) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_i32<T>(&mut self, n: i32) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_u48<T>(&mut self, n: u64) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_i48<T>(&mut self, n: i64) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_u64<T>(&mut self, n: u64) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_i64<T>(&mut self, n: i64) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_u128<T>(&mut self, n: u128) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_i128<T>(&mut self, n: i128) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_uint<T>(&mut self, n: u64, nbytes: usize) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_int<T>(&mut self, n: i64, nbytes: usize) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_uint128<T>(&mut self, n: u128, nbytes: usize) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_int128<T>(&mut self, n: i128, nbytes: usize) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_f32<T>(&mut self, n: f32) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,
pub fn write_f64<T>(&mut self, n: f64) -> Result<(), Error> where
T: ByteOrder,
T: ByteOrder,