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// Copyright (c) The camino Contributors
// SPDX-License-Identifier: MIT OR Apache-2.0
//! Adapted from
use std::{env, process::Command, str};
// The rustc-cfg strings below are *not* public API. Please let us know by
// opening a GitHub issue if your build environment requires some way to enable
// these cfgs other than by executing our build script.
fn main() {
let compiler = match rustc_version() {
Some(compiler) => compiler,
None => return,
};
// NOTE:
// Adding a new cfg gated by Rust version MUST be accompanied by an addition to the matrix in
// .github/workflows/ci.yml.
if compiler.minor >= 44 {
println!("cargo:rustc-cfg=path_buf_capacity");
}
if compiler.minor >= 56 {
println!("cargo:rustc-cfg=shrink_to");
}
// Stable and beta 1.63 have a stable try_reserve_2.
if (compiler.minor >= 63
&& (compiler.channel == ReleaseChannel::Stable || compiler.channel == ReleaseChannel::Beta))
|| compiler.minor >= 64
{
println!("cargo:rustc-cfg=try_reserve_2");
}
}
struct Compiler {
minor: u32,
channel: ReleaseChannel,
}
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum ReleaseChannel {
Stable,
Beta,
Nightly,
}
fn rustc_version() -> Option<Compiler> {
let rustc = env::var_os("RUSTC")?;
let output = Command::new(rustc).arg("--version").output().ok()?;
let version = str::from_utf8(&output.stdout).ok()?;
let mut pieces = version.split('.');
if pieces.next() != Some("rustc 1") {
return None;
}
let minor = pieces.next()?.parse().ok()?;
let channel = if version.contains("nightly") {
ReleaseChannel::Nightly
} else if version.contains("beta") {
ReleaseChannel::Beta
} else {
ReleaseChannel::Stable
};
Some(Compiler { minor, channel })
}