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Replace version check with probing Backtrace api
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Original file line number | Diff line number | Diff line change |
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@@ -1,35 +1,59 @@ | ||
use std::env; | ||
use std::process::Command; | ||
use std::str::{self, FromStr}; | ||
use std::fs; | ||
use std::path::Path; | ||
use std::process::{Command, ExitStatus}; | ||
|
||
fn main() { | ||
let compiler = match rustc_version() { | ||
Some(compiler) => compiler, | ||
None => return, | ||
}; | ||
// This code exercises the surface area that we expect of the std Backtrace | ||
// type. If the current toolchain is able to compile it, we go ahead and use | ||
// backtrace in anyhow. | ||
const PROBE: &str = r#" | ||
#![feature(backtrace)] | ||
#![allow(dead_code)] | ||
if compiler.minor >= 40 && compiler.nightly { | ||
println!("cargo:rustc-cfg=backtrace"); | ||
} | ||
} | ||
use std::backtrace::{Backtrace, BacktraceStatus}; | ||
use std::error::Error; | ||
use std::fmt::{self, Display}; | ||
struct Compiler { | ||
minor: u32, | ||
nightly: bool, | ||
} | ||
#[derive(Debug)] | ||
struct E; | ||
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()?; | ||
impl Display for E { | ||
fn fmt(&self, _formatter: &mut fmt::Formatter) -> fmt::Result { | ||
unimplemented!() | ||
} | ||
} | ||
let mut pieces = version.split('.'); | ||
if pieces.next() != Some("rustc 1") { | ||
return None; | ||
impl Error for E { | ||
fn backtrace(&self) -> Option<&Backtrace> { | ||
let backtrace = Backtrace::capture(); | ||
match backtrace.status() { | ||
BacktraceStatus::Captured | BacktraceStatus::Disabled | _ => {} | ||
} | ||
unimplemented!() | ||
} | ||
} | ||
"#; | ||
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||
let next = pieces.next()?; | ||
let minor = u32::from_str(next).ok()?; | ||
let nightly = version.contains("nightly") || version.contains("dev"); | ||
Some(Compiler { minor, nightly }) | ||
fn main() { | ||
match compile_probe() { | ||
Some(status) if status.success() => println!("cargo:rustc-cfg=backtrace"), | ||
_ => {} | ||
} | ||
} | ||
|
||
fn compile_probe() -> Option<ExitStatus> { | ||
let rustc = env::var_os("RUSTC")?; | ||
let out_dir = env::var_os("OUT_DIR")?; | ||
let probefile = Path::new(&out_dir).join("lib.rs"); | ||
fs::write(&probefile, PROBE).ok()?; | ||
Command::new(rustc) | ||
.arg("--edition=2018") | ||
.arg("--crate-name=anyhow_build") | ||
.arg("--crate-type=lib") | ||
.arg("--emit=metadata") | ||
.arg("--out-dir") | ||
.arg(out_dir) | ||
.arg(probefile) | ||
.status() | ||
.ok() | ||
} |