Vendor things

third-party/vendor/eyre/build.rs

@@ -0,0 +1,132 @@
+use std::env;
+use std::ffi::OsString;
+use std::fs;
+use std::path::Path;
+use std::process::{Command, ExitStatus};
+use std::str;
+
+// 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 eyre.
+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()
+}
+
+// TODO factor this toolchain parsing and related tests into its own file
+#[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()?;
+    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)
+}