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Diffstat (limited to 'src/lib.rs')
| -rw-r--r-- | src/lib.rs | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/src/lib.rs b/src/lib.rs new file mode 100644 index 0000000..501cad6 --- /dev/null +++ b/src/lib.rs @@ -0,0 +1,210 @@ +//! 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(target_arch = "wasm32")] +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)) + } +} |