Struct io_streams::BufReaderLineWriter
source · [−]pub struct BufReaderLineWriter<Inner: HalfDuplex> { /* private fields */ }
Expand description
Wraps a reader and writer and buffers input and output to and from it,
flushing the writer whenever a newline (0x0a
, '\n'
) is detected on
output.
The BufDuplexer
struct wraps a reader and writer and buffers their
input and 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 BufReaderLineWriter
. It does exactly that.
Like BufDuplexer
, a BufReaderLineWriter
’s buffer will also be flushed
when the BufReaderLineWriter
goes out of scope or when its internal
buffer is full.
If there’s still a partial line in the buffer when the
BufReaderLineWriter
is dropped, it will flush those contents.
Examples
We can use BufReaderLineWriter
to write one line at a time, significantly
reducing the number of actual writes to the file.
use char_device::CharDevice;
use io_streams::BufReaderLineWriter;
use std::fs;
use std::io::prelude::*;
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 = CharDevice::open("/dev/tty")?;
let mut file = BufReaderLineWriter::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 `BufReaderLineWriter` to finish
// writing.
file.flush()?;
// Confirm the whole poem was written.
assert_eq!(fs::read("poem.txt")?, &road_not_taken[..]);
Ok(())
}
Implementations
sourceimpl<Inner: HalfDuplex> BufReaderLineWriter<Inner>
impl<Inner: HalfDuplex> BufReaderLineWriter<Inner>
sourcepub fn new(inner: Inner) -> Self
pub fn new(inner: Inner) -> Self
Creates a new BufReaderLineWriter
.
Examples
use char_device::CharDevice;
use io_streams::BufReaderLineWriter;
fn main() -> std::io::Result<()> {
let file = CharDevice::open("/dev/tty")?;
let file = BufReaderLineWriter::new(file);
Ok(())
}
sourcepub fn with_capacities(
reader_capacity: usize,
writer_capacity: usize,
inner: Inner
) -> Self
pub fn with_capacities(
reader_capacity: usize,
writer_capacity: usize,
inner: Inner
) -> Self
Creates a new BufReaderLineWriter
with a specified capacities for the
internal buffers.
Examples
use char_device::CharDevice;
use io_streams::BufReaderLineWriter;
fn main() -> std::io::Result<()> {
let file = CharDevice::open("/dev/tty")?;
let file = BufReaderLineWriter::with_capacities(10, 100, file);
Ok(())
}
sourcepub fn get_ref(&self) -> &Inner
pub fn get_ref(&self) -> &Inner
Gets a reference to the underlying writer.
Examples
use char_device::CharDevice;
use io_streams::BufReaderLineWriter;
fn main() -> std::io::Result<()> {
let file = CharDevice::open("/dev/tty")?;
let file = BufReaderLineWriter::new(file);
let reference = file.get_ref();
Ok(())
}
sourcepub fn get_mut(&mut self) -> &mut Inner
pub fn get_mut(&mut self) -> &mut Inner
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 char_device::CharDevice;
use io_streams::BufReaderLineWriter;
fn main() -> std::io::Result<()> {
let file = CharDevice::open("/dev/tty")?;
let mut file = BufReaderLineWriter::new(file);
// we can use reference just like file
let reference = file.get_mut();
Ok(())
}
sourcepub fn into_inner(self) -> Result<Inner, IntoInnerError<Self>>
pub fn into_inner(self) -> Result<Inner, IntoInnerError<Self>>
Unwraps this BufReaderLineWriter
, 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 char_device::CharDevice;
use io_streams::BufReaderLineWriter;
fn main() -> std::io::Result<()> {
let file = CharDevice::open("/dev/tty")?;
let writer: BufReaderLineWriter<CharDevice> = BufReaderLineWriter::new(file);
let file: CharDevice = writer.into_inner()?;
Ok(())
}
Trait Implementations
sourceimpl<Inner: HalfDuplex + AsFd> AsFd for BufReaderLineWriter<Inner>
impl<Inner: HalfDuplex + AsFd> AsFd for BufReaderLineWriter<Inner>
sourcefn as_fd(&self) -> BorrowedFd<'_>
fn as_fd(&self) -> BorrowedFd<'_>
Borrows the file descriptor. Read more
sourceimpl<Inner: HalfDuplex + AsRawFd> AsRawFd for BufReaderLineWriter<Inner>
impl<Inner: HalfDuplex + AsRawFd> AsRawFd for BufReaderLineWriter<Inner>
sourceimpl<Inner: HalfDuplex> BufRead for BufReaderLineWriter<Inner>
impl<Inner: HalfDuplex> BufRead for BufReaderLineWriter<Inner>
sourcefn fill_buf(&mut self) -> Result<&[u8]>
fn fill_buf(&mut self) -> Result<&[u8]>
Returns the contents of the internal buffer, filling it with more data from the inner reader if it is empty. Read more
sourcefn consume(&mut self, amt: usize)
fn consume(&mut self, amt: usize)
Tells this buffer that amt
bytes have been consumed from the buffer,
so they should no longer be returned in calls to read
. Read more
sourcefn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>
fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize>
Read all bytes into buf
until the delimiter byte
or EOF is reached. Read more
sourcefn read_line(&mut self, buf: &mut String) -> Result<usize>
fn read_line(&mut self, buf: &mut String) -> Result<usize>
Read all bytes until a newline (the 0xA
byte) is reached, and append
them to the provided buffer. You do not need to clear the buffer before
appending. Read more
sourcefn has_data_left(&mut self) -> Result<bool, Error>
fn has_data_left(&mut self) -> Result<bool, Error>
buf_read_has_data_left
)Check if the underlying Read
has any data left to be read. Read more
sourceimpl<Inner: HalfDuplex> Debug for BufReaderLineWriter<Inner> where
Inner: Debug,
impl<Inner: HalfDuplex> Debug for BufReaderLineWriter<Inner> where
Inner: Debug,
sourceimpl<Inner: HalfDuplex> Read for BufReaderLineWriter<Inner>
impl<Inner: HalfDuplex> Read for BufReaderLineWriter<Inner>
sourcefn read(&mut self, buf: &mut [u8]) -> Result<usize>
fn read(&mut self, buf: &mut [u8]) -> Result<usize>
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
sourcefn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>
Like read
, except that it reads into a slice of buffers. Read more
sourcefn is_read_vectored(&self) -> bool
fn is_read_vectored(&self) -> bool
can_vector
)Determines if this Read
er has an efficient read_vectored
implementation. Read more
1.0.0 · sourcefn read_to_end(&mut self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>
fn read_to_end(&mut self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>
Read all bytes until EOF in this source, placing them into buf
. Read more
1.0.0 · sourcefn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>
Read all bytes until EOF in this source, appending them to buf
. Read more
1.6.0 · sourcefn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>
Read the exact number of bytes required to fill buf
. Read more
sourcefn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> Result<(), Error>
fn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> Result<(), Error>
read_buf
)Pull some bytes from this source into the specified buffer. Read more
sourcefn read_buf_exact(&mut self, buf: &mut ReadBuf<'_>) -> Result<(), Error>
fn read_buf_exact(&mut self, buf: &mut ReadBuf<'_>) -> Result<(), Error>
read_buf
)Read the exact number of bytes required to fill buf
. Read more
1.0.0 · sourcefn by_ref(&mut self) -> &mut Self
fn by_ref(&mut self) -> &mut Self
Creates a “by reference” adaptor for this instance of Read
. Read more
sourceimpl<Inner: HalfDuplex> Write for BufReaderLineWriter<Inner>
impl<Inner: HalfDuplex> Write for BufReaderLineWriter<Inner>
sourcefn write(&mut self, buf: &[u8]) -> Result<usize>
fn write(&mut self, buf: &[u8]) -> Result<usize>
Write a buffer into this writer, returning how many bytes were written. Read more
sourcefn flush(&mut self) -> Result<()>
fn flush(&mut self) -> Result<()>
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
sourcefn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>
sourcefn is_write_vectored(&self) -> bool
fn is_write_vectored(&self) -> bool
can_vector
)Determines if this Write
r has an efficient write_vectored
implementation. Read more
sourcefn write_all(&mut self, buf: &[u8]) -> Result<()>
fn write_all(&mut self, buf: &[u8]) -> Result<()>
Attempts to write an entire buffer into this writer. Read more
sourcefn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>
fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<()>
write_all_vectored
)Attempts to write multiple buffers into this writer. Read more
Auto Trait Implementations
impl<Inner> RefUnwindSafe for BufReaderLineWriter<Inner> where
Inner: RefUnwindSafe,
impl<Inner> Send for BufReaderLineWriter<Inner> where
Inner: Send,
impl<Inner> Sync for BufReaderLineWriter<Inner> where
Inner: Sync,
impl<Inner> Unpin for BufReaderLineWriter<Inner> where
Inner: Unpin,
impl<Inner> UnwindSafe for BufReaderLineWriter<Inner> where
Inner: UnwindSafe,
Blanket Implementations
sourceimpl<T> AsFilelike for T where
T: AsFd,
impl<T> AsFilelike for T where
T: AsFd,
sourcefn as_filelike(&self) -> BorrowedFd<'_>
fn as_filelike(&self) -> BorrowedFd<'_>
Borrows the reference. Read more
sourcefn as_filelike_view<Target>(&self) -> FilelikeView<'_, Target> where
Target: FilelikeViewType,
fn as_filelike_view<Target>(&self) -> FilelikeView<'_, Target> where
Target: FilelikeViewType,
Return a borrowing view of a resource which dereferences to a &Target
. Read more
sourceimpl<T> AsGrip for T where
T: AsFd,
impl<T> AsGrip for T where
T: AsFd,
sourcefn as_grip(&self) -> BorrowedFd<'_>
fn as_grip(&self) -> BorrowedFd<'_>
Extracts the grip.
sourceimpl<T> AsRawFilelike for T where
T: AsRawFd,
impl<T> AsRawFilelike for T where
T: AsRawFd,
sourcefn as_raw_filelike(&self) -> i32
fn as_raw_filelike(&self) -> i32
Returns the raw value.
sourceimpl<T> AsRawGrip for T where
T: AsRawFd,
impl<T> AsRawGrip for T where
T: AsRawFd,
sourcefn as_raw_grip(&self) -> i32
fn as_raw_grip(&self) -> i32
Extracts the raw grip.
sourceimpl<T> AsRawSocketlike for T where
T: AsRawFd,
impl<T> AsRawSocketlike for T where
T: AsRawFd,
sourcefn as_raw_socketlike(&self) -> i32
fn as_raw_socketlike(&self) -> i32
Returns the raw value.
sourceimpl<T> AsSocketlike for T where
T: AsFd,
impl<T> AsSocketlike for T where
T: AsFd,
sourcefn as_socketlike(&self) -> BorrowedFd<'_>
fn as_socketlike(&self) -> BorrowedFd<'_>
Borrows the reference.
sourcefn as_socketlike_view<Target>(&self) -> SocketlikeView<'_, Target> where
Target: SocketlikeViewType,
fn as_socketlike_view<Target>(&self) -> SocketlikeView<'_, Target> where
Target: SocketlikeViewType,
Return a borrowing view of a resource which dereferences to a &Target
. Read more
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
sourceimpl<T> FileIoExt for T where
T: AsFilelike,
impl<T> FileIoExt for T where
T: AsFilelike,
sourcefn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error>
fn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error>
Announce the expected access pattern of the data at the given offset.
sourcefn allocate(&self, offset: u64, len: u64) -> Result<(), Error>
fn allocate(&self, offset: u64, len: u64) -> Result<(), Error>
Allocate space in the file, increasing the file size as needed, and ensuring that there are no holes under the given range. Read more
sourcefn read(&self, buf: &mut [u8]) -> Result<usize, Error>
fn read(&self, buf: &mut [u8]) -> Result<usize, Error>
Pull some bytes from this source into the specified buffer, returning how many bytes were read. Read more
sourcefn read_exact(&self, buf: &mut [u8]) -> Result<(), Error>
fn read_exact(&self, buf: &mut [u8]) -> Result<(), Error>
Read the exact number of bytes required to fill buf
. Read more
sourcefn read_at(&self, buf: &mut [u8], offset: u64) -> Result<usize, Error>
fn read_at(&self, buf: &mut [u8], offset: u64) -> Result<usize, Error>
Reads a number of bytes starting from a given offset. Read more
sourcefn read_exact_at(&self, buf: &mut [u8], offset: u64) -> Result<(), Error>
fn read_exact_at(&self, buf: &mut [u8], offset: u64) -> Result<(), Error>
Reads the exact number of byte required to fill buf from the given offset. Read more
sourcefn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>
fn read_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>
Like read
, except that it reads into a slice of buffers. Read more
sourcefn read_vectored_at(
&self,
bufs: &mut [IoSliceMut<'_>],
offset: u64
) -> Result<usize, Error>
fn read_vectored_at(
&self,
bufs: &mut [IoSliceMut<'_>],
offset: u64
) -> Result<usize, Error>
Is to read_vectored
what read_at
is to read
.
sourcefn is_read_vectored_at(&self) -> bool
fn is_read_vectored_at(&self) -> bool
Determines if this Read
er has an efficient read_vectored_at
implementation. Read more
sourcefn read_to_end(&self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>
fn read_to_end(&self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>
Read all bytes until EOF in this source, placing them into buf
. Read more
sourcefn read_to_end_at(
&self,
buf: &mut Vec<u8, Global>,
offset: u64
) -> Result<usize, Error>
fn read_to_end_at(
&self,
buf: &mut Vec<u8, Global>,
offset: u64
) -> Result<usize, Error>
Read all bytes, starting at offset
, until EOF in this source, placing
them into buf
. Read more
sourcefn read_to_string(&self, buf: &mut String) -> Result<usize, Error>
fn read_to_string(&self, buf: &mut String) -> Result<usize, Error>
Read all bytes until EOF in this source, appending them to buf
. Read more
sourcefn read_to_string_at(
&self,
buf: &mut String,
offset: u64
) -> Result<usize, Error>
fn read_to_string_at(
&self,
buf: &mut String,
offset: u64
) -> Result<usize, Error>
Read all bytes, starting at offset
, until EOF in this source,
appending them to buf
. Read more
sourcefn peek(&self, buf: &mut [u8]) -> Result<usize, Error>
fn peek(&self, buf: &mut [u8]) -> Result<usize, Error>
Read bytes from the current position without advancing the current position. Read more
sourcefn write(&self, buf: &[u8]) -> Result<usize, Error>
fn write(&self, buf: &[u8]) -> Result<usize, Error>
Write a buffer into this writer, returning how many bytes were written. Read more
sourcefn write_all(&self, buf: &[u8]) -> Result<(), Error>
fn write_all(&self, buf: &[u8]) -> Result<(), Error>
Attempts to write an entire buffer into this writer. Read more
sourcefn write_at(&self, buf: &[u8], offset: u64) -> Result<usize, Error>
fn write_at(&self, buf: &[u8], offset: u64) -> Result<usize, Error>
Writes a number of bytes starting from a given offset. Read more
sourcefn write_all_at(&self, buf: &[u8], offset: u64) -> Result<(), Error>
fn write_all_at(&self, buf: &[u8], offset: u64) -> Result<(), Error>
Attempts to write an entire buffer starting from a given offset. Read more
sourcefn write_vectored(&self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>
fn write_vectored(&self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>
Like write
, except that it writes from a slice of buffers. Read more
sourcefn write_vectored_at(
&self,
bufs: &[IoSlice<'_>],
offset: u64
) -> Result<usize, Error>
fn write_vectored_at(
&self,
bufs: &[IoSlice<'_>],
offset: u64
) -> Result<usize, Error>
Is to write_vectored
what write_at
is to write
.
sourcefn is_write_vectored_at(&self) -> bool
fn is_write_vectored_at(&self) -> bool
Determines if this Write
r has an efficient write_vectored_at
implementation. Read more
sourcefn flush(&self) -> Result<(), Error>
fn flush(&self) -> Result<(), Error>
Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more
sourcefn write_fmt(&self, fmt: Arguments<'_>) -> Result<(), Error>
fn write_fmt(&self, fmt: Arguments<'_>) -> Result<(), Error>
Writes a formatted string into this writer, returning any error encountered. Read more
sourcefn seek(&self, pos: SeekFrom) -> Result<u64, Error>
fn seek(&self, pos: SeekFrom) -> Result<u64, Error>
Seek to an offset, in bytes, in a stream. Read more
sourcefn stream_position(&self) -> Result<u64, Error>
fn stream_position(&self) -> Result<u64, Error>
Returns the current seek position from the start of the stream. Read more
sourcefn read_exact_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> Result<(), Error>
fn read_exact_vectored(&self, bufs: &mut [IoSliceMut<'_>]) -> Result<(), Error>
Is to read_vectored
what read_exact
is to read
.
sourcefn read_exact_vectored_at(
&self,
bufs: &mut [IoSliceMut<'_>],
offset: u64
) -> Result<(), Error>
fn read_exact_vectored_at(
&self,
bufs: &mut [IoSliceMut<'_>],
offset: u64
) -> Result<(), Error>
Is to read_exact_vectored
what read_exact_at
is to read_exact
.
sourceimpl<T> GetSetFdFlags for T
impl<T> GetSetFdFlags for T
sourcefn get_fd_flags(&self) -> Result<FdFlags, Error> where
T: AsFilelike,
fn get_fd_flags(&self) -> Result<FdFlags, Error> where
T: AsFilelike,
Query the “status” flags for the self
file descriptor.
sourcefn new_set_fd_flags(&self, fd_flags: FdFlags) -> Result<SetFdFlags<T>, Error> where
T: AsFilelike,
fn new_set_fd_flags(&self, fd_flags: FdFlags) -> Result<SetFdFlags<T>, Error> where
T: AsFilelike,
Create a new SetFdFlags
value for use with set_fd_flags
. Read more
sourcefn set_fd_flags(&mut self, set_fd_flags: SetFdFlags<T>) -> Result<(), Error> where
T: AsFilelike,
fn set_fd_flags(&mut self, set_fd_flags: SetFdFlags<T>) -> Result<(), Error> where
T: AsFilelike,
Set the “status” flags for the self
file descriptor. Read more
sourceimpl<T> IsReadWrite for T where
T: AsFilelike,
impl<T> IsReadWrite for T where
T: AsFilelike,
sourceimpl<T> IsTerminal for T where
T: AsFilelike,
impl<T> IsTerminal for T where
T: AsFilelike,
sourcefn is_terminal(&self) -> bool
fn is_terminal(&self) -> bool
Test whether this output stream is attached to a terminal. Read more