vendor/is-terminal-0.4.5/src/lib.rs - toolchain/rustc - Git at Google

 //! is-terminal is a simple utility that answers one question:
 //!
 //! > Is this a terminal?
 //!
 //! A "terminal", also known as a "tty", is an I/O device which may be
 //! interactive and may support color and other special features. This crate
 //! doesn't provide any of those features; it just answers this one question.
 //!
 //! On Unix-family platforms, this is effectively the same as the [`isatty`]
 //! function for testing whether a given stream is a terminal, though it
 //! accepts high-level stream types instead of raw file descriptors.
 //!
 //! On Windows, it uses a variety of techniques to determine whether the
 //! given stream is a terminal.
 //!
 //! # Example
 //!
 //! ```rust
 //! use is_terminal::IsTerminal;
 //!
 //! if std::io::stdout().is_terminal() {
 //!     println!("stdout is a terminal")
 //! }
 //! ```
 //!
 //! [`isatty`]: https://man7.org/linux/man-pages/man3/isatty.3.html

 #![cfg_attr(unix, no_std)]

 #[cfg(not(target_os = "unknown"))]
 use io_lifetimes::AsFilelike;
 #[cfg(windows)]
 use io_lifetimes::BorrowedHandle;
 #[cfg(target_os = "hermit")]
 use std::os::hermit::io::AsRawFd;
 #[cfg(windows)]
 use std::os::windows::io::AsRawHandle;
 #[cfg(windows)]
 use windows_sys::Win32::Foundation::HANDLE;

 pub trait IsTerminal {
     /// Returns true if this is a terminal.
     ///
     /// # Example
     ///
     /// ```
     /// use is_terminal::IsTerminal;
     ///
     /// if std::io::stdout().is_terminal() {
     ///     println!("stdout is a terminal")
     /// }
     /// ```
     fn is_terminal(&self) -> bool;
 }

 #[cfg(not(target_os = "unknown"))]
 impl<Stream: AsFilelike> IsTerminal for Stream {
     #[inline]
     fn is_terminal(&self) -> bool {
         #[cfg(any(unix, target_os = "wasi"))]
         {
             rustix::termios::isatty(self)
         }

         #[cfg(target_os = "hermit")]
         {
             hermit_abi::isatty(self.as_filelike().as_raw_fd())
         }

         #[cfg(windows)]
         {
             handle_is_console(self.as_filelike())
         }
     }
 }

 // The Windows implementation here is copied from `handle_is_console` in
 // std/src/sys/windows/io.rs in Rust at revision
 // d7b0bcb20f2f7d5f3ea3489d56ece630147e98f5.

 #[cfg(windows)]
 fn handle_is_console(handle: BorrowedHandle<'_>) -> bool {
     use windows_sys::Win32::System::Console::{
         GetConsoleMode, GetStdHandle, STD_ERROR_HANDLE, STD_INPUT_HANDLE, STD_OUTPUT_HANDLE,
     };

     let handle = handle.as_raw_handle();

     unsafe {
         // A null handle means the process has no console.
         if handle.is_null() {
             return false;
         }

         let mut out = 0;
         if GetConsoleMode(handle as HANDLE, &mut out) != 0 {
             // False positives aren't possible. If we got a console then we definitely have a console.
             return true;
         }

         // At this point, we *could* have a false negative. We can determine that this is a true
         // negative if we can detect the presence of a console on any of the standard I/O streams. If
         // another stream has a console, then we know we're in a Windows console and can therefore
         // trust the negative.
         for std_handle in [STD_INPUT_HANDLE, STD_OUTPUT_HANDLE, STD_ERROR_HANDLE] {
             let std_handle = GetStdHandle(std_handle);
             if std_handle != 0
                 && std_handle != handle as HANDLE
                 && GetConsoleMode(std_handle, &mut out) != 0
             {
                 return false;
             }
         }

         // Otherwise, we fall back to an msys hack to see if we can detect the presence of a pty.
         msys_tty_on(handle as HANDLE)
     }
 }

 /// Returns true if there is an MSYS tty on the given handle.
 ///
 /// This incoproates d7b0bcb20f2f7d5f3ea3489d56ece630147e98f5
 #[cfg(windows)]
 unsafe fn msys_tty_on(handle: HANDLE) -> bool {
     use std::ffi::c_void;
     use windows_sys::Win32::{
         Foundation::MAX_PATH,
         Storage::FileSystem::{
             FileNameInfo, GetFileInformationByHandleEx, GetFileType, FILE_TYPE_PIPE,
         },
     };

     // Early return if the handle is not a pipe.
     if GetFileType(handle) != FILE_TYPE_PIPE {
         return false;
     }

     /// Mirrors windows_sys::Win32::Storage::FileSystem::FILE_NAME_INFO, giving
     /// it a fixed length that we can stack allocate
     #[repr(C)]
     #[allow(non_snake_case)]
     struct FILE_NAME_INFO {
         FileNameLength: u32,
         FileName: [u16; MAX_PATH as usize],
     }
     let mut name_info = FILE_NAME_INFO {
         FileNameLength: 0,
         FileName: [0; MAX_PATH as usize],
     };
     // Safety: buffer length is fixed.
     let res = GetFileInformationByHandleEx(
         handle,
         FileNameInfo,
         &mut name_info as *mut _ as *mut c_void,
         std::mem::size_of::<FILE_NAME_INFO>() as u32,
     );
     if res == 0 {
         return false;
     }

     // Use `get` because `FileNameLength` can be out of range.
     let s = match name_info
         .FileName
         .get(..name_info.FileNameLength as usize / 2)
     {
         None => return false,
         Some(s) => s,
     };
     let name = String::from_utf16_lossy(s);
     // Get the file name only.
     let name = name.rsplit('\\').next().unwrap_or(&name);
     // 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
     // the file name begins with either the strings 'msys-' or 'cygwin-'.)
     let is_msys = name.starts_with("msys-") || name.starts_with("cygwin-");
     let is_pty = name.contains("-pty");
     is_msys && is_pty
 }

 #[cfg(target_os = "unknown")]
 impl IsTerminal for std::io::Stdin {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl IsTerminal for std::io::Stdout {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl IsTerminal for std::io::Stderr {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl<'a> IsTerminal for std::io::StdinLock<'a> {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl<'a> IsTerminal for std::io::StdoutLock<'a> {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl<'a> IsTerminal for std::io::StderrLock<'a> {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl<'a> IsTerminal for std::fs::File {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl IsTerminal for std::process::ChildStdin {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl IsTerminal for std::process::ChildStdout {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(target_os = "unknown")]
 impl IsTerminal for std::process::ChildStderr {
     #[inline]
     fn is_terminal(&self) -> bool {
         false
     }
 }

 #[cfg(test)]
 mod tests {
     #[cfg(not(target_os = "unknown"))]
     use super::IsTerminal;

     #[test]
     #[cfg(windows)]
     fn stdin() {
         assert_eq!(
             atty::is(atty::Stream::Stdin),
             std::io::stdin().is_terminal()
         )
     }

     #[test]
     #[cfg(windows)]
     fn stdout() {
         assert_eq!(
             atty::is(atty::Stream::Stdout),
             std::io::stdout().is_terminal()
         )
     }

     #[test]
     #[cfg(windows)]
     fn stderr() {
         assert_eq!(
             atty::is(atty::Stream::Stderr),
             std::io::stderr().is_terminal()
         )
     }

     #[test]
     #[cfg(any(unix, target_os = "wasi"))]
     fn stdin() {
         unsafe {
             assert_eq!(
                 atty::is(atty::Stream::Stdin),
                 rustix::io::stdin().is_terminal()
             )
         }
     }

     #[test]
     #[cfg(any(unix, target_os = "wasi"))]
     fn stdout() {
         unsafe {
             assert_eq!(
                 atty::is(atty::Stream::Stdout),
                 rustix::io::stdout().is_terminal()
             )
         }
     }

     #[test]
     #[cfg(any(unix, target_os = "wasi"))]
     fn stderr() {
         unsafe {
             assert_eq!(
                 atty::is(atty::Stream::Stderr),
                 rustix::io::stderr().is_terminal()
             )
         }
     }

     #[test]
     #[cfg(any(unix, target_os = "wasi"))]
     fn stdin_vs_libc() {
         unsafe {
             assert_eq!(
                 libc::isatty(libc::STDIN_FILENO) != 0,
                 rustix::io::stdin().is_terminal()
             )
         }
     }

     #[test]
     #[cfg(any(unix, target_os = "wasi"))]
     fn stdout_vs_libc() {
         unsafe {
             assert_eq!(
                 libc::isatty(libc::STDOUT_FILENO) != 0,
                 rustix::io::stdout().is_terminal()
             )
         }
     }

     #[test]
     #[cfg(any(unix, target_os = "wasi"))]
     fn stderr_vs_libc() {
         unsafe {
             assert_eq!(
                 libc::isatty(libc::STDERR_FILENO) != 0,
                 rustix::io::stderr().is_terminal()
             )
         }
     }

     // Verify that the msys_tty_on function works with long path.
     #[test]
     #[cfg(windows)]
     fn msys_tty_on_path_length() {
         use std::{fs::File, os::windows::io::AsRawHandle};
         use windows_sys::Win32::Foundation::MAX_PATH;

         let dir = tempfile::tempdir().expect("Unable to create temporary directory");
         let file_path = dir.path().join("ten_chars_".repeat(25));
         // Ensure that the path is longer than MAX_PATH.
         assert!(file_path.to_string_lossy().len() > MAX_PATH as usize);
         let file = File::create(file_path).expect("Unable to create file");

         assert!(!unsafe { crate::msys_tty_on(file.as_raw_handle() as isize) });
     }
 }
	//! is-terminal is a simple utility that answers one question:
	//!
	//! > Is this a terminal?
	//!
	//! A "terminal", also known as a "tty", is an I/O device which may be
	//! interactive and may support color and other special features. This crate
	//! doesn't provide any of those features; it just answers this one question.
	//!
	//! On Unix-family platforms, this is effectively the same as the [`isatty`]
	//! function for testing whether a given stream is a terminal, though it
	//! accepts high-level stream types instead of raw file descriptors.
	//!
	//! On Windows, it uses a variety of techniques to determine whether the
	//! given stream is a terminal.
	//!
	//! # Example
	//!
	//! ```rust
	//! use is_terminal::IsTerminal;
	//!
	//! if std::io::stdout().is_terminal() {
	//! println!("stdout is a terminal")
	//! }
	//! ```
	//!
	//! [`isatty`]: https://man7.org/linux/man-pages/man3/isatty.3.html

	#![cfg_attr(unix, no_std)]

	#[cfg(not(target_os = "unknown"))]
	use io_lifetimes::AsFilelike;
	#[cfg(windows)]
	use io_lifetimes::BorrowedHandle;
	#[cfg(target_os = "hermit")]
	use std::os::hermit::io::AsRawFd;
	#[cfg(windows)]
	use std::os::windows::io::AsRawHandle;
	#[cfg(windows)]
	use windows_sys::Win32::Foundation::HANDLE;

	pub trait IsTerminal {
	/// Returns true if this is a terminal.
	///
	/// # Example
	///
	/// ```
	/// use is_terminal::IsTerminal;
	///
	/// if std::io::stdout().is_terminal() {
	/// println!("stdout is a terminal")
	/// }
	/// ```
	fn is_terminal(&self) -> bool;
	}

	#[cfg(not(target_os = "unknown"))]
	impl<Stream: AsFilelike> IsTerminal for Stream {
	#[inline]
	fn is_terminal(&self) -> bool {
	#[cfg(any(unix, target_os = "wasi"))]
	{
	rustix::termios::isatty(self)
	}

	#[cfg(target_os = "hermit")]
	{
	hermit_abi::isatty(self.as_filelike().as_raw_fd())
	}

	#[cfg(windows)]
	{
	handle_is_console(self.as_filelike())
	}
	}
	}

	// The Windows implementation here is copied from `handle_is_console` in
	// std/src/sys/windows/io.rs in Rust at revision
	// d7b0bcb20f2f7d5f3ea3489d56ece630147e98f5.

	#[cfg(windows)]
	fn handle_is_console(handle: BorrowedHandle<'_>) -> bool {
	use windows_sys::Win32::System::Console::{
	GetConsoleMode, GetStdHandle, STD_ERROR_HANDLE, STD_INPUT_HANDLE, STD_OUTPUT_HANDLE,
	};

	let handle = handle.as_raw_handle();

	unsafe {
	// A null handle means the process has no console.
	if handle.is_null() {
	return false;
	}

	let mut out = 0;
	if GetConsoleMode(handle as HANDLE, &mut out) != 0 {
	// False positives aren't possible. If we got a console then we definitely have a console.
	return true;
	}

	// At this point, we could have a false negative. We can determine that this is a true
	// negative if we can detect the presence of a console on any of the standard I/O streams. If
	// another stream has a console, then we know we're in a Windows console and can therefore
	// trust the negative.
	for std_handle in [STD_INPUT_HANDLE, STD_OUTPUT_HANDLE, STD_ERROR_HANDLE] {
	let std_handle = GetStdHandle(std_handle);
	if std_handle != 0
	&& std_handle != handle as HANDLE
	&& GetConsoleMode(std_handle, &mut out) != 0
	{
	return false;
	}
	}

	// Otherwise, we fall back to an msys hack to see if we can detect the presence of a pty.
	msys_tty_on(handle as HANDLE)
	}
	}

	/// Returns true if there is an MSYS tty on the given handle.
	///
	/// This incoproates d7b0bcb20f2f7d5f3ea3489d56ece630147e98f5
	#[cfg(windows)]
	unsafe fn msys_tty_on(handle: HANDLE) -> bool {
	use std::ffi::c_void;
	use windows_sys::Win32::{
	Foundation::MAX_PATH,
	Storage::FileSystem::{
	FileNameInfo, GetFileInformationByHandleEx, GetFileType, FILE_TYPE_PIPE,
	},
	};

	// Early return if the handle is not a pipe.
	if GetFileType(handle) != FILE_TYPE_PIPE {
	return false;
	}

	/// Mirrors windows_sys::Win32::Storage::FileSystem::FILE_NAME_INFO, giving
	/// it a fixed length that we can stack allocate
	#[repr(C)]
	#[allow(non_snake_case)]
	struct FILE_NAME_INFO {
	FileNameLength: u32,
	FileName: [u16; MAX_PATH as usize],
	}
	let mut name_info = FILE_NAME_INFO {
	FileNameLength: 0,
	FileName: [0; MAX_PATH as usize],
	};
	// Safety: buffer length is fixed.
	let res = GetFileInformationByHandleEx(
	handle,
	FileNameInfo,
	&mut name_info as mut _ as mut c_void,
	std::mem::size_of::<FILE_NAME_INFO>() as u32,
	);
	if res == 0 {
	return false;
	}

	// Use `get` because `FileNameLength` can be out of range.
	let s = match name_info
	.FileName
	.get(..name_info.FileNameLength as usize / 2)
	{
	None => return false,
	Some(s) => s,
	};
	let name = String::from_utf16_lossy(s);
	// Get the file name only.
	let name = name.rsplit('\\').next().unwrap_or(&name);
	// 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
	// the file name begins with either the strings 'msys-' or 'cygwin-'.)
	let is_msys = name.starts_with("msys-") \|\| name.starts_with("cygwin-");
	let is_pty = name.contains("-pty");
	is_msys && is_pty
	}

	#[cfg(target_os = "unknown")]
	impl IsTerminal for std::io::Stdin {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl IsTerminal for std::io::Stdout {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl IsTerminal for std::io::Stderr {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl<'a> IsTerminal for std::io::StdinLock<'a> {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl<'a> IsTerminal for std::io::StdoutLock<'a> {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl<'a> IsTerminal for std::io::StderrLock<'a> {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl<'a> IsTerminal for std::fs::File {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl IsTerminal for std::process::ChildStdin {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl IsTerminal for std::process::ChildStdout {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(target_os = "unknown")]
	impl IsTerminal for std::process::ChildStderr {
	#[inline]
	fn is_terminal(&self) -> bool {
	false
	}
	}

	#[cfg(test)]
	mod tests {
	#[cfg(not(target_os = "unknown"))]
	use super::IsTerminal;

	#[test]
	#[cfg(windows)]
	fn stdin() {
	assert_eq!(
	atty::is(atty::Stream::Stdin),
	std::io::stdin().is_terminal()
	)
	}

	#[test]
	#[cfg(windows)]
	fn stdout() {
	assert_eq!(
	atty::is(atty::Stream::Stdout),
	std::io::stdout().is_terminal()
	)
	}

	#[test]
	#[cfg(windows)]
	fn stderr() {
	assert_eq!(
	atty::is(atty::Stream::Stderr),
	std::io::stderr().is_terminal()
	)
	}

	#[test]
	#[cfg(any(unix, target_os = "wasi"))]
	fn stdin() {
	unsafe {
	assert_eq!(
	atty::is(atty::Stream::Stdin),
	rustix::io::stdin().is_terminal()
	)
	}
	}

	#[test]
	#[cfg(any(unix, target_os = "wasi"))]
	fn stdout() {
	unsafe {
	assert_eq!(
	atty::is(atty::Stream::Stdout),
	rustix::io::stdout().is_terminal()
	)
	}
	}

	#[test]
	#[cfg(any(unix, target_os = "wasi"))]
	fn stderr() {
	unsafe {
	assert_eq!(
	atty::is(atty::Stream::Stderr),
	rustix::io::stderr().is_terminal()
	)
	}
	}

	#[test]
	#[cfg(any(unix, target_os = "wasi"))]
	fn stdin_vs_libc() {
	unsafe {
	assert_eq!(
	libc::isatty(libc::STDIN_FILENO) != 0,
	rustix::io::stdin().is_terminal()
	)
	}
	}

	#[test]
	#[cfg(any(unix, target_os = "wasi"))]
	fn stdout_vs_libc() {
	unsafe {
	assert_eq!(
	libc::isatty(libc::STDOUT_FILENO) != 0,
	rustix::io::stdout().is_terminal()
	)
	}
	}

	#[test]
	#[cfg(any(unix, target_os = "wasi"))]
	fn stderr_vs_libc() {
	unsafe {
	assert_eq!(
	libc::isatty(libc::STDERR_FILENO) != 0,
	rustix::io::stderr().is_terminal()
	)
	}
	}

	// Verify that the msys_tty_on function works with long path.
	#[test]
	#[cfg(windows)]
	fn msys_tty_on_path_length() {
	use std::{fs::File, os::windows::io::AsRawHandle};
	use windows_sys::Win32::Foundation::MAX_PATH;

	let dir = tempfile::tempdir().expect("Unable to create temporary directory");
	let file_path = dir.path().join("ten_chars_".repeat(25));
	// Ensure that the path is longer than MAX_PATH.
	assert!(file_path.to_string_lossy().len() > MAX_PATH as usize);
	let file = File::create(file_path).expect("Unable to create file");

	assert!(!unsafe { crate::msys_tty_on(file.as_raw_handle() as isize) });
	}
	}