Struct servo::process::Stdio1.0.0[][src]

pub struct Stdio(Stdio);
Expand description

Describes what to do with a standard I/O stream for a child process when passed to the stdin, stdout, and stderr methods of Command.

Tuple Fields

0: Stdio

Implementations

A new pipe should be arranged to connect the parent and child processes.

Examples

With stdout:

use std::process::{Command, Stdio};

let output = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "Hello, world!\n");
// Nothing echoed to console

With stdin:

use std::io::Write;
use std::process::{Command, Stdio};

let mut child = Command::new("rev")
    .stdin(Stdio::piped())
    .stdout(Stdio::piped())
    .spawn()
    .expect("Failed to spawn child process");

let mut stdin = child.stdin.take().expect("Failed to open stdin");
std::thread::spawn(move || {
    stdin.write_all("Hello, world!".as_bytes()).expect("Failed to write to stdin");
});

let output = child.wait_with_output().expect("Failed to read stdout");
assert_eq!(String::from_utf8_lossy(&output.stdout), "!dlrow ,olleH");

Writing more than a pipe buffer’s worth of input to stdin without also reading stdout and stderr at the same time may cause a deadlock. This is an issue when running any program that doesn’t guarantee that it reads its entire stdin before writing more than a pipe buffer’s worth of output. The size of a pipe buffer varies on different targets.

The child inherits from the corresponding parent descriptor.

Examples

With stdout:

use std::process::{Command, Stdio};

let output = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::inherit())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// "Hello, world!" echoed to console

With stdin:

use std::process::{Command, Stdio};
use std::io::{self, Write};

let output = Command::new("rev")
    .stdin(Stdio::inherit())
    .stdout(Stdio::piped())
    .output()
    .expect("Failed to execute command");

print!("You piped in the reverse of: ");
io::stdout().write_all(&output.stdout).unwrap();

This stream will be ignored. This is the equivalent of attaching the stream to /dev/null.

Examples

With stdout:

use std::process::{Command, Stdio};

let output = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::null())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// Nothing echoed to console

With stdin:

use std::process::{Command, Stdio};

let output = Command::new("rev")
    .stdin(Stdio::null())
    .stdout(Stdio::piped())
    .output()
    .expect("Failed to execute command");

assert_eq!(String::from_utf8_lossy(&output.stdout), "");
// Ignores any piped-in input

Trait Implementations

Formats the value using the given formatter. Read more

Converts a ChildStderr into a Stdio

Examples
use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .arg("non_existing_file.txt")
    .stderr(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let cat = Command::new("cat")
    .arg("-")
    .stdin(reverse.stderr.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

assert_eq!(
    String::from_utf8_lossy(&cat.stdout),
    "rev: cannot open non_existing_file.txt: No such file or directory\n"
);

Converts a ChildStdin into a Stdio

Examples

ChildStdin will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let reverse = Command::new("rev")
    .stdin(Stdio::piped())
    .spawn()
    .expect("failed reverse command");

let _echo = Command::new("echo")
    .arg("Hello, world!")
    .stdout(reverse.stdin.unwrap()) // Converted into a Stdio here
    .output()
    .expect("failed echo command");

// "!dlrow ,olleH" echoed to console

Converts a ChildStdout into a Stdio

Examples

ChildStdout will be converted to Stdio using Stdio::from under the hood.

use std::process::{Command, Stdio};

let hello = Command::new("echo")
    .arg("Hello, world!")
    .stdout(Stdio::piped())
    .spawn()
    .expect("failed echo command");

let reverse = Command::new("rev")
    .stdin(hello.stdout.unwrap())  // Converted into a Stdio here
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH\n");

Converts a File into a Stdio

Examples

File will be converted to Stdio using Stdio::from under the hood.

use std::fs::File;
use std::process::Command;

// With the `foo.txt` file containing `Hello, world!"
let file = File::open("foo.txt").unwrap();

let reverse = Command::new("rev")
    .stdin(file)  // Implicit File conversion into a Stdio
    .output()
    .expect("failed reverse command");

assert_eq!(reverse.stdout, b"!dlrow ,olleH");

Performs the conversion.

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

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

Convert

Convert

The alignment of pointer.

The type for initializers.

Initializes a with the given initializer. Read more

Dereferences the given pointer. Read more

Mutably dereferences the given pointer. Read more

Drops the object pointed to by the given pointer. Read more

Should always be Self

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.