Vendor things

third-party/vendor/is-terminal/README.md

@@ -0,0 +1,116 @@
+<div align="center">
+  <h1><code>is-terminal</code></h1>
+
+  <p>
+    <strong>Test whether a given stream is a terminal</strong>
+  </p>
+
+  <p>
+    <a href="https://github.com/sunfishcode/is-terminal/actions?query=workflow%3ACI"><img src="https://github.com/sunfishcode/is-terminal/workflows/CI/badge.svg" alt="Github Actions CI Status" /></a>
+    <a href="https://crates.io/crates/is-terminal"><img src="https://img.shields.io/crates/v/is-terminal.svg" alt="crates.io page" /></a>
+    <a href="https://docs.rs/is-terminal"><img src="https://docs.rs/is-terminal/badge.svg" alt="docs.rs docs" /></a>
+  </p>
+</div>
+
+As of Rust 1.70, most users should use the [`IsTerminal`] trait in the Rust
+standard library instead of this crate.
+
+On Unix platforms, this crate now uses libc, so that the implementation
+matches what's in std. Users wishing to use the rustix-based implementation
+can use the [rustix-is-terminal] crate instead.
+
+[rustix-is-terminal]: https://crates.io/crates/rustix-is-terminal
+
+<hr>
+
+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.
+
+This crate is derived from [the atty crate] with [PR \#51] bug fix and
+[PR \#54] port to windows-sys applied. The only additional difference is that
+the atty crate only accepts stdin, stdout, or stderr, while this crate accepts
+any stream. In particular, this crate does not access any stream that is not
+passed to it, in accordance with [I/O safety].
+
+[PR \#51]: https://github.com/softprops/atty/pull/51
+[PR \#54]: https://github.com/softprops/atty/pull/54
+
+## Example
+
+```rust
+use is_terminal::IsTerminal;
+
+fn main() {
+    if std::io::stdout().is_terminal() {
+        println!("Stdout is a terminal");
+    } else {
+        println!("Stdout is not a terminal");
+    }
+}
+```
+
+## Testing
+
+This library is tested on both Unix-family and Windows platforms.
+
+To test it on a platform manually, use the provided `stdio` example program.
+When run normally, it prints this:
+
+```bash
+$ cargo run --example stdio
+stdin? true
+stdout? true
+stderr? true
+```
+
+To test stdin, pipe some text to the program:
+
+```bash
+$ cat | cargo run --example stdio
+stdin? false
+stdout? true
+stderr? true
+```
+
+To test stdout, pipe the program to something:
+
+```bash
+$ cargo run --example stdio | cat
+stdin? true
+stdout? false
+stderr? true
+```
+
+To test stderr, pipe the program to something redirecting stderr:
+
+```bash
+$ cargo run --example stdio 2>&1 | cat
+stdin? true
+stdout? false
+stderr? false
+```
+
+# Minimum Supported Rust Version (MSRV)
+
+This crate currently works on the version of [Rust on Debian stable], which is
+currently Rust 1.63. This policy may change in the future, in minor version
+releases, so users using a fixed version of Rust should pin to a specific
+version of this crate.
+
+[`isatty`]: https://man7.org/linux/man-pages/man3/isatty.3.html
+[the atty crate]: https://crates.io/crates/atty
+[I/O safety]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md
+[Rust on Debian stable]: https://packages.debian.org/stable/rust/rustc
+[`IsTerminal`]: https://doc.rust-lang.org/stable/std/io/trait.IsTerminal.html