Struct TeeReader 

pub struct TeeReader<R, W> { /* private fields */ }

Reader wrapper that mirrors read bytes into a branch writer.

TeeReader forwards reads to the source reader and writes every successfully read byte into the branch writer while the stream is consumed. If the branch writer fails, the source bytes have already been read from the inner reader and the branch error is returned.

Seeking a TeeReader seeks only the source reader. It does not seek or otherwise modify the branch writer; bytes mirrored after the seek are simply appended or written according to the branch writer’s own state.

Examples

use std::io::{
    Cursor,
    Read,
};

use qubit_io::TeeReader;

let source = Cursor::new(b"abc".to_vec());
let branch = Vec::new();
let mut reader = TeeReader::new(source, branch);

let mut data = Vec::new();
reader.read_to_end(&mut data)?;
let (_source, branch) = reader.into_inner();

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

Implementations

impl<R, W> TeeReader<R, W>

pub fn new(reader: R, branch: W) -> Self

Creates a tee reader.

Parameters

• reader: Source reader.
• branch: Writer that receives the bytes successfully read.

Returns

A new tee reader.

pub fn reader_ref(&self) -> &R

Returns an immutable reference to the source reader.

Returns

The source reader reference.

pub fn reader_mut(&mut self) -> &mut R

Returns a mutable reference to the source reader.

Returns

The source reader reference.

pub fn branch_ref(&self) -> &W

Returns an immutable reference to the branch writer.

Returns

The branch writer reference.

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

Returns a mutable reference to the branch writer.

Returns

The branch writer reference.

pub fn into_inner(self) -> (R, W)

Consumes this wrapper and returns the source reader and branch writer.

Returns

A tuple containing the source reader and branch writer.

Trait Implementations

impl<R, W> Read for TeeReader<R, W>

where R: Read, W: Write,

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

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

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

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

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

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

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

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

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

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

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

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

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

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

fn read_array<const N: usize>(&mut self) -> Result<[u8; N], Error>

where Self: Sized,

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

Read and return a fixed array of bytes from this source.

impl<R, W> Seek for TeeReader<R, W>

where R: Seek,

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

Seeks the source reader without touching the branch writer.

Parameters

• position: Target position for the source reader.

Returns

The new source reader position.

Errors

Returns the seek error reported by the source reader.

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.