blob: b155f085214322d52893b99dc4a26881be29dc7c [file] [log] [blame]
//! atty is a simple utility that answers one question
//! > is this a tty?
//!
//! usage is just as simple
//!
//! ```
//! if atty::is(atty::Stream::Stdout) {
//! println!("i'm a tty")
//! }
//! ```
//!
//! ```
//! if atty::isnt(atty::Stream::Stdout) {
//! println!("i'm not a tty")
//! }
//! ```
#![cfg_attr(unix, no_std)]
#[cfg(unix)]
extern crate libc;
#[cfg(windows)]
extern crate winapi;
#[cfg(windows)]
use winapi::shared::minwindef::DWORD;
#[cfg(windows)]
use winapi::shared::ntdef::WCHAR;
/// possible stream sources
#[derive(Clone, Copy, Debug)]
pub enum Stream {
Stdout,
Stderr,
Stdin,
}
/// returns true if this is a tty
#[cfg(all(unix, not(target_arch = "wasm32")))]
pub fn is(stream: Stream) -> bool {
extern crate libc;
let fd = match stream {
Stream::Stdout => libc::STDOUT_FILENO,
Stream::Stderr => libc::STDERR_FILENO,
Stream::Stdin => libc::STDIN_FILENO,
};
unsafe { libc::isatty(fd) != 0 }
}
/// returns true if this is a tty
#[cfg(target_os = "hermit")]
pub fn is(stream: Stream) -> bool {
extern crate hermit_abi;
let fd = match stream {
Stream::Stdout => hermit_abi::STDOUT_FILENO,
Stream::Stderr => hermit_abi::STDERR_FILENO,
Stream::Stdin => hermit_abi::STDIN_FILENO,
};
hermit_abi::isatty(fd)
}
/// returns true if this is a tty
#[cfg(windows)]
pub fn is(stream: Stream) -> bool {
use winapi::um::winbase::{
STD_ERROR_HANDLE as STD_ERROR, STD_INPUT_HANDLE as STD_INPUT,
STD_OUTPUT_HANDLE as STD_OUTPUT,
};
let (fd, others) = match stream {
Stream::Stdin => (STD_INPUT, [STD_ERROR, STD_OUTPUT]),
Stream::Stderr => (STD_ERROR, [STD_INPUT, STD_OUTPUT]),
Stream::Stdout => (STD_OUTPUT, [STD_INPUT, STD_ERROR]),
};
if unsafe { console_on_any(&[fd]) } {
// False positives aren't possible. If we got a console then
// we definitely have a tty on stdin.
return true;
}
// At this point, we *could* have a false negative. We can determine that
// this is true negative if we can detect the presence of a console on
// any of the other streams. If another stream has a console, then we know
// we're in a Windows console and can therefore trust the negative.
if unsafe { console_on_any(&others) } {
return false;
}
// Otherwise, we fall back to a very strange msys hack to see if we can
// sneakily detect the presence of a tty.
unsafe { msys_tty_on(fd) }
}
/// returns true if this is _not_ a tty
pub fn isnt(stream: Stream) -> bool {
!is(stream)
}
/// Returns true if any of the given fds are on a console.
#[cfg(windows)]
unsafe fn console_on_any(fds: &[DWORD]) -> bool {
use winapi::um::{consoleapi::GetConsoleMode, processenv::GetStdHandle};
for &fd in fds {
let mut out = 0;
let handle = GetStdHandle(fd);
if GetConsoleMode(handle, &mut out) != 0 {
return true;
}
}
false
}
/// Returns true if there is an MSYS tty on the given handle.
#[cfg(windows)]
unsafe fn msys_tty_on(fd: DWORD) -> bool {
use std::{mem, slice};
use winapi::{
ctypes::c_void,
shared::minwindef::MAX_PATH,
um::{
fileapi::FILE_NAME_INFO, minwinbase::FileNameInfo, processenv::GetStdHandle,
winbase::GetFileInformationByHandleEx,
},
};
let size = mem::size_of::<FILE_NAME_INFO>();
let mut name_info_bytes = vec![0u8; size + MAX_PATH * mem::size_of::<WCHAR>()];
let res = GetFileInformationByHandleEx(
GetStdHandle(fd),
FileNameInfo,
&mut *name_info_bytes as *mut _ as *mut c_void,
name_info_bytes.len() as u32,
);
if res == 0 {
return false;
}
let name_info: &FILE_NAME_INFO = &*(name_info_bytes.as_ptr() as *const FILE_NAME_INFO);
let s = slice::from_raw_parts(
name_info.FileName.as_ptr(),
name_info.FileNameLength as usize / 2,
);
let name = String::from_utf16_lossy(s);
// This checks whether 'pty' exists in the file name, which indicates that
// a pseudo-terminal is attached. To mitigate against false positives
// (e.g., an actual file name that contains 'pty'), we also require that
// either the strings 'msys-' or 'cygwin-' are in the file name as well.)
let is_msys = name.contains("msys-") || name.contains("cygwin-");
let is_pty = name.contains("-pty");
is_msys && is_pty
}
/// returns true if this is a tty
#[cfg(any(target_arch = "wasm32", target_env = "sgx"))]
pub fn is(_stream: Stream) -> bool {
false
}
#[cfg(test)]
mod tests {
use super::{is, Stream};
#[test]
#[cfg(windows)]
fn is_err() {
// appveyor pipes its output
assert!(!is(Stream::Stderr))
}
#[test]
#[cfg(windows)]
fn is_out() {
// appveyor pipes its output
assert!(!is(Stream::Stdout))
}
#[test]
#[cfg(windows)]
fn is_in() {
assert!(is(Stream::Stdin))
}
#[test]
#[cfg(unix)]
fn is_err() {
assert!(is(Stream::Stderr))
}
#[test]
#[cfg(unix)]
fn is_out() {
assert!(is(Stream::Stdout))
}
#[test]
#[cfg(target_os = "macos")]
fn is_in() {
// macos on travis seems to pipe its input
assert!(is(Stream::Stdin))
}
#[test]
#[cfg(all(not(target_os = "macos"), unix))]
fn is_in() {
assert!(is(Stream::Stdin))
}
}