Struct TeeWriter 

pub struct TeeWriter<P, B> { /* private fields */ }

Writer wrapper that mirrors accepted bytes into a branch writer.

TeeWriter writes to the primary writer first, then writes exactly the accepted bytes into the branch writer with Write::write_all. If the branch writer fails, the primary writer may already have accepted bytes and the branch error is returned.

Seeking moves the primary writer first, then seeks the branch writer to the primary writer’s resulting absolute position. If the branch seek fails, the primary writer may already have moved.

Examples

use std::io::Write;

use qubit_io::TeeWriter;

let primary = Vec::new();
let branch = Vec::new();
let mut writer = TeeWriter::new(primary, branch);

writer.write_all(b"abc")?;
let (primary, branch) = writer.into_inner();

assert_eq!(b"abc", primary.as_slice());
assert_eq!(b"abc", branch.as_slice());

Implementations

impl<P, B> TeeWriter<P, B>

pub fn new(primary: P, branch: B) -> Self

Creates a tee writer.

Parameters

• primary: Primary destination writer.
• branch: Secondary writer that mirrors accepted bytes.

Returns

A new tee writer.

pub fn primary_ref(&self) -> &P

Returns an immutable reference to the primary writer.

Returns

The primary writer reference.

pub fn primary_mut(&mut self) -> &mut P

Returns a mutable reference to the primary writer.

Returns

The primary writer reference.

pub fn branch_ref(&self) -> &B

Returns an immutable reference to the branch writer.

Returns

The branch writer reference.

pub fn branch_mut(&mut self) -> &mut B

Returns a mutable reference to the branch writer.

Returns

The branch writer reference.

pub fn into_inner(self) -> (P, B)

Consumes this wrapper and returns both wrapped writers.

Returns

A tuple containing the primary writer and branch writer.

Trait Implementations

impl<P, B> Seek for TeeWriter<P, B>

where P: Seek, B: Seek,

fn seek(&mut self, position: SeekFrom) -> Result<u64>

Seeks both wrapped writers to the same resulting absolute position.

Parameters

• position: Target position for the primary writer.

Returns

The new primary writer position.

Errors

Returns the primary seek error, or the branch seek error after the primary writer has already moved.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.

impl<P, B> Write for TeeWriter<P, B>

where P: Write, B: Write,

fn write(&mut self, buffer: &[u8]) -> Result<usize>

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

fn write_all(&mut self, buf: &[u8]) -> Result<(), Error>

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.