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use std::env;
use std::env::VarError;
use std::fs::File;
use std::io::Read;
use std::io::Write;
use std::path::Path;
use std::path::PathBuf;
use std::process;
// % rustc +stable --version
// rustc 1.26.0 (a77568041 2018-05-07)
// % rustc +beta --version
// rustc 1.27.0-beta.1 (03fb2f447 2018-05-09)
// % rustc +nightly --version
// rustc 1.27.0-nightly (acd3871ba 2018-05-10)
fn version_is_nightly(version: &str) -> bool {
version.contains("nightly")
}
fn cfg_rust_version() {
let rustc = env::var("RUSTC").expect("RUSTC unset");
let mut child = process::Command::new(rustc)
.args(&["--version"])
.stdin(process::Stdio::null())
.stdout(process::Stdio::piped())
.spawn()
.expect("spawn rustc");
let mut rustc_version = String::new();
child
.stdout
.as_mut()
.expect("stdout")
.read_to_string(&mut rustc_version)
.expect("read_to_string");
assert!(child.wait().expect("wait").success());
if version_is_nightly(&rustc_version) {
println!("cargo:rustc-cfg=rustc_nightly");
}
}
fn cfg_serde() {
match env::var("CARGO_FEATURE_WITH_SERDE") {
Ok(_) => {
println!("cargo:rustc-cfg=serde");
}
Err(VarError::NotUnicode(..)) => panic!(),
Err(VarError::NotPresent) => {}
}
}
fn out_dir() -> PathBuf {
PathBuf::from(env::var("OUT_DIR").expect("OUT_DIR"))
}
fn version() -> String {
env::var("CARGO_PKG_VERSION").expect("CARGO_PKG_VERSION")
}
fn write_version() {
let version = version();
let version_ident = format!(
"VERSION_{}",
version.replace(".", "_").replace("-", "_").to_uppercase()
);
let mut file = File::create(Path::join(&out_dir(), "version.rs")).expect("open");
writeln!(file, "/// protobuf crate version").unwrap();
writeln!(file, "pub const VERSION: &'static str = \"{}\";", version).unwrap();
writeln!(file, "/// This symbol is used by codegen").unwrap();
writeln!(file, "#[doc(hidden)]").unwrap();
writeln!(
file,
"pub const VERSION_IDENT: &'static str = \"{}\";",
version_ident
)
.unwrap();
writeln!(
file,
"/// This symbol can be referenced to assert that proper version of crate is used"
)
.unwrap();
writeln!(file, "pub const {}: () = ();", version_ident).unwrap();
file.flush().unwrap();
}
fn main() {
cfg_rust_version();
cfg_serde();
write_version();
}
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