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|
use std::env;
use std::ffi::OsString;
use std::fs;
use std::path::Path;
use std::process::{Command, ExitStatus};
use std::str;
const BACKTRACE_PROBE: &str = r#"
#![feature(backtrace)]
#![allow(dead_code)]
use std::backtrace::{Backtrace, BacktraceStatus};
use std::error::Error;
use std::fmt::{self, Display};
#[derive(Debug)]
struct E;
impl Display for E {
fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result {
unimplemented!()
}
}
impl Error for E {
fn backtrace(&self) -> Option<&Backtrace> {
let backtrace = Backtrace::capture();
match backtrace.status() {
BacktraceStatus::Captured | BacktraceStatus::Disabled | _ => {}
}
unimplemented!()
}
}
"#;
const TRACK_CALLER_PROBE: &str = r#"
#![allow(dead_code)]
#[track_caller]
fn foo() {
let _location = std::panic::Location::caller();
}
"#;
fn main() {
match compile_probe(BACKTRACE_PROBE) {
Some(status) if status.success() => println!("cargo:rustc-cfg=backtrace"),
_ => {}
}
match compile_probe(TRACK_CALLER_PROBE) {
Some(status) if status.success() => println!("cargo:rustc-cfg=track_caller"),
_ => {}
}
let version = match rustc_version_info() {
Some(version) => version,
None => return,
};
version.toolchain.set_feature();
if version.minor < 52 {
println!("cargo:rustc-cfg=eyre_no_fmt_arguments_as_str");
}
if version.minor < 58 {
println!("cargo:rustc-cfg=eyre_no_fmt_args_capture");
}
}
fn compile_probe(probe: &str) -> Option<ExitStatus> {
let rustc = env::var_os("RUSTC")?;
let out_dir = env::var_os("OUT_DIR")?;
let probefile = Path::new(&out_dir).join("probe.rs");
fs::write(&probefile, probe).ok()?;
Command::new(rustc)
.arg("--edition=2018")
.arg("--crate-name=eyre_build")
.arg("--crate-type=lib")
.arg("--emit=metadata")
.arg("--out-dir")
.arg(out_dir)
.arg(probefile)
.status()
.ok()
}
#[derive(PartialEq)]
enum Toolchain {
Stable,
Beta,
Nightly,
}
impl Toolchain {
fn set_feature(self) {
match self {
Toolchain::Nightly => println!("cargo:rustc-cfg=nightly"),
Toolchain::Beta => println!("cargo:rustc-cfg=beta"),
Toolchain::Stable => println!("cargo:rustc-cfg=stable"),
}
}
}
struct VersionInfo {
minor: u32,
toolchain: Toolchain,
}
fn rustc_version_info() -> Option<VersionInfo> {
let rustc = env::var_os("RUSTC").unwrap_or_else(|| OsString::from("rustc"));
let output = Command::new(rustc).arg("--version").output().ok()?;
let version = str::from_utf8(&output.stdout).ok()?.trim();
let mut pieces = version.split(['.', ' ', '-']);
if pieces.next() != Some("rustc") {
return None;
}
let _major: u32 = pieces.next()?.parse().ok()?;
let minor = pieces.next()?.parse().ok()?;
let _patch: u32 = pieces.next()?.parse().ok()?;
let toolchain = match pieces.next() {
Some("beta") => Toolchain::Beta,
Some("nightly") => Toolchain::Nightly,
_ => Toolchain::Stable,
};
let version = VersionInfo { minor, toolchain };
Some(version)
}
|
