134 lines
4.0 KiB
Rust
134 lines
4.0 KiB
Rust
// Copyright © 2018–2021 Trevor Spiteri
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// Copying and distribution of this file, with or without
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// modification, are permitted in any medium without royalty provided
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// the copyright notice and this notice are preserved. This file is
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// offered as-is, without any warranty.
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#![allow(dead_code)]
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#![allow(unused_variables)]
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#![cfg_attr(feature = "fail-on-warnings", deny(warnings))]
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use std::{
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env,
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ffi::OsString,
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fs::{self, File},
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io::{Result as IoResult, Write},
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path::{Path, PathBuf},
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process::Command,
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};
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struct Environment {
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out_dir: PathBuf,
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rustc: OsString,
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}
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fn main() {
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let env = Environment {
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out_dir: PathBuf::from(cargo_env("OUT_DIR")),
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rustc: cargo_env("RUSTC"),
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};
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}
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#[derive(PartialEq)]
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struct Optional(bool);
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impl Environment {
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// 1. If optional feature is availble (both with and without flag), output:
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// cargo:rustc-cfg=<name>
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// 2. If feature is available with flag (both optional and not), output:
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// cargo:rustc-cfg=nightly_<name>
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// 3. If non-optional feature is not available, panic.
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fn check_feature(
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&self,
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name: &str,
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optional: Optional,
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contents: &str,
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nightly_features: Option<&str>,
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) {
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let try_dir = self.out_dir.join(format!("try_{}", name));
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let filename = format!("try_{}.rs", name);
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create_dir_or_panic(&try_dir);
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println!("$ cd {:?}", try_dir);
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#[derive(PartialEq)]
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enum Iteration {
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Stable,
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Unstable,
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}
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let mut found = false;
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for i in &[Iteration::Stable, Iteration::Unstable] {
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let s;
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let file_contents = match *i {
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Iteration::Stable => contents,
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Iteration::Unstable => match nightly_features {
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Some(features) => {
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s = format!("#![feature({})]\n{}", features, contents);
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&s
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}
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None => continue,
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},
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};
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create_file_or_panic(&try_dir.join(&filename), file_contents);
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let mut cmd = Command::new(&self.rustc);
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cmd.current_dir(&try_dir)
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.args(&[&filename, "--emit=dep-info,metadata"]);
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println!("$ {:?}", cmd);
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let status = cmd
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.status()
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.unwrap_or_else(|_| panic!("Unable to execute: {:?}", cmd));
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if status.success() {
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if optional.0 {
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println!("cargo:rustc-cfg={}", name);
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}
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if *i == Iteration::Unstable {
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println!("cargo:rustc-cfg=nightly_{}", name);
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}
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found = true;
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break;
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}
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}
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remove_dir_or_panic(&try_dir);
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assert!(
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found || optional.0,
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"essential feature not supported by compiler: {}",
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name
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);
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}
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}
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fn cargo_env(name: &str) -> OsString {
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env::var_os(name)
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.unwrap_or_else(|| panic!("environment variable not found: {}, please use cargo", name))
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}
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fn remove_dir(dir: &Path) -> IoResult<()> {
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if !dir.exists() {
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return Ok(());
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}
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assert!(dir.is_dir(), "Not a directory: {:?}", dir);
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println!("$ rm -r {:?}", dir);
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fs::remove_dir_all(dir)
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}
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fn remove_dir_or_panic(dir: &Path) {
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remove_dir(dir).unwrap_or_else(|_| panic!("Unable to remove directory: {:?}", dir));
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}
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fn create_dir(dir: &Path) -> IoResult<()> {
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println!("$ mkdir -p {:?}", dir);
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fs::create_dir_all(dir)
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}
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fn create_dir_or_panic(dir: &Path) {
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create_dir(dir).unwrap_or_else(|_| panic!("Unable to create directory: {:?}", dir));
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}
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fn create_file_or_panic(filename: &Path, contents: &str) {
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println!("$ printf '%s' {:?}... > {:?}", &contents[0..20], filename);
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let mut file =
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File::create(filename).unwrap_or_else(|_| panic!("Unable to create file: {:?}", filename));
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file.write_all(contents.as_bytes())
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.unwrap_or_else(|_| panic!("Unable to write to file: {:?}", filename));
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}
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