Struct PipeReader

pub struct PipeReader(/* private fields */);

Read end of an anonymous pipe.

Implementations

impl PipeReader

pub fn try_clone(&self) -> Result<Self>

Create a new PipeReader instance that shares the same underlying file description.

Examples

use std::fs;
use std::io::{pipe, Write};
use std::process::Command;
const NUM_SLOT: u8 = 2;
const NUM_PROC: u8 = 5;
const OUTPUT: &str = "work.txt";

let mut jobs = vec![];
let (reader, mut writer) = pipe()?;

// Write NUM_SLOT characters the pipe.
writer.write_all(&[b'|'; NUM_SLOT as usize])?;

// Spawn several processes that read a character from the pipe, do some work, then
// write back to the pipe. When the pipe is empty, the processes block, so only
// NUM_SLOT processes can be working at any given time.
for _ in 0..NUM_PROC {
    jobs.push(
        Command::new("bash")
            .args(["-c",
                &format!(
                     "read -n 1\n\
                      echo -n 'x' >> '{OUTPUT}'\n\
                      echo -n '|'",
                ),
            ])
            .stdin(reader.try_clone()?)
            .stdout(writer.try_clone()?)
            .spawn()?,
    );
}

// Wait for all jobs to finish.
for mut job in jobs {
    job.wait()?;
}

// Check our work and clean up.
let xs = fs::read_to_string(OUTPUT)?;
fs::remove_file(OUTPUT)?;
assert_eq!(xs, "x".repeat(NUM_PROC.into()));

Trait Implementations

impl AsFd for PipeReader

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor.

impl AsHandle for PipeReader

Available on Windows only.

fn as_handle(&self) -> BorrowedHandle<'_>

Borrows the handle.

impl AsRawFd for PipeReader

fn as_raw_fd(&self) -> RawFd

Extracts the raw file descriptor.

impl AsRawHandle for PipeReader

Available on Windows only.

fn as_raw_handle(&self) -> RawHandle

Extracts the raw handle.

impl Debug for PipeReader

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<OwnedFd> for PipeReader

fn from(owned_fd: OwnedFd) -> Self

Converts to this type from the input type.

impl From<OwnedHandle> for PipeReader

Available on Windows only.

fn from(owned_handle: OwnedHandle) -> Self

Converts to this type from the input type.

impl From<PipeReader> for OwnedFd

fn from(pipe: PipeReader) -> Self

Converts to this type from the input type.

impl From<PipeReader> for OwnedHandle

Available on Windows only.

fn from(pipe: PipeReader) -> Self

Converts to this type from the input type.

impl From<PipeReader> for Stdio

fn from(pipe: PipeReader) -> Self

Converts to this type from the input type.

impl FromRawFd for PipeReader

unsafe fn from_raw_fd(raw_fd: RawFd) -> Self

Constructs a new instance of Self from the given raw file descriptor.

impl FromRawHandle for PipeReader

Available on Windows only.

unsafe fn from_raw_handle(raw_handle: RawHandle) -> Self

Constructs a new I/O object from the specified raw handle.

impl IntoRawFd for PipeReader

fn into_raw_fd(self) -> RawFd

Consumes this object, returning the raw underlying file descriptor.

impl IntoRawHandle for PipeReader

Available on Windows only.

fn into_raw_handle(self) -> RawHandle

Consumes this object, returning the raw underlying handle.

impl Read for &PipeReader

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.

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

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 #69941)

Determines if this Reader has an efficient read_vectored implementation.

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

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

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

🔬This is a nightly-only experimental API. (read_buf #78485)

Pull some bytes from this source into the specified buffer.

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

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

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

Reads the exact number of bytes required to fill buf.

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

🔬This is a nightly-only experimental API. (read_buf #78485)

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

Creates a “by reference” adaptor 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: Read>(self, next: R) -> Chain<Self, R>

where 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.

impl Read for PipeReader

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.

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

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 #69941)

Determines if this Reader has an efficient read_vectored implementation.

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

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

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

🔬This is a nightly-only experimental API. (read_buf #78485)

Pull some bytes from this source into the specified buffer.

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

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

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

Reads the exact number of bytes required to fill buf.

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

🔬This is a nightly-only experimental API. (read_buf #78485)

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

Creates a “by reference” adaptor 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: Read>(self, next: R) -> Chain<Self, R>

where 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.