extern crate autocfg;

use std::env;
use std::io;

mod support;

fn main() {
    let args: Vec<_> = env::args().skip(1).collect();
    if args.is_empty() {
        // With no arguments, this must be a (harness-free) test run.
        // (we're using system binaries as wrappers, so ignore other platforms)
        if cfg!(unix) {
            test_wrappers();
        }
    } else {
        // Otherwise we're acting like a no-op rustc wrapper, ignoring almost everything.
        for arg in args {
            match &*arg {
                // Add our own version so we can check that the wrapper is used for that.
                "--version" => println!("release: 12345.6789.0"),

                // Read all input so the writer doesn't get EPIPE when we exit.
                "-" => {
                    let stdin = io::stdin();
                    let _ = io::copy(&mut stdin.lock(), &mut io::sink());
                }

                _ => {}
            }
        }
    }
}

/// Tests that autocfg uses the RUSTC_WRAPPER and/or RUSTC_WORKSPACE_WRAPPER
/// environment variables when running rustc.
fn test_wrappers() {
    fn set(name: &str, value: Option<bool>) {
        match value {
            Some(true) => env::set_var(name, "/usr/bin/env"),
            Some(false) => env::set_var(name, "/bin/false"),
            None => env::remove_var(name),
        }
    }

    let out = support::out_dir();

    // This is used as a heuristic to detect rust-lang/cargo#9601.
    env::set_var("CARGO_ENCODED_RUSTFLAGS", "");

    // No wrapper, a good pass-through wrapper, and a bad wrapper.
    let variants = [None, Some(true), Some(false)];

    for &workspace in &variants {
        for &rustc in &variants {
            set("RUSTC_WRAPPER", rustc);
            set("RUSTC_WORKSPACE_WRAPPER", workspace);

            let ac = autocfg::AutoCfg::with_dir(out.as_ref()).unwrap();
            if rustc == Some(false) || workspace == Some(false) {
                // Everything should fail with bad wrappers.
                assert!(!ac.probe_type("usize"));
            } else {
                // Try known good and bad types for the wrapped rustc.
                assert!(ac.probe_type("usize"));
                assert!(!ac.probe_type("mesize"));
            }
            // Either way, we should have found the inner rustc version.
            assert!(ac.probe_rustc_version(1, 0));
        }
    }

    // Finally, make sure that `RUSTC_WRAPPER` is applied outermost
    // by using something (ourself) that doesn't pass through at all.
    let wrap_ignored = env::current_exe().unwrap();
    env::set_var("RUSTC_WRAPPER", &wrap_ignored);
    env::set_var("RUSTC_WORKSPACE_WRAPPER", "/bin/false");
    let ac = autocfg::AutoCfg::with_dir(out.as_ref()).unwrap();
    assert!(ac.probe_type("mesize")); // anything goes!

    // Make sure we also got the version from that wrapper.
    assert!(ac.probe_rustc_version(12345, 6789));
}