forked from abdul124/rust-core_io
79 lines
2.5 KiB
Rust
79 lines
2.5 KiB
Rust
extern crate rustc_version;
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use std::env;
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use std::fs::File;
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use std::io::Write;
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use std::path::PathBuf;
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use std::ops::{Neg,Sub};
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/*
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* Let me explain this hack. For the sync shell script it's easiest if every
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* line in mapping.rs looks exactly the same. This means that specifying an
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* array literal is not possible. include!() can only expand to expressions, so
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* just specifying the contents of an array is also not possible.
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*
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* This leaves us with trying to find an expression in which every line looks
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* the same. This can be done using the `-` operator. This can be a unary
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* operator (first thing on the first line), or a binary operator (later
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* lines). That is exactly what's going on here, and Neg and Sub simply build a
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* vector of the operangs.
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*/
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struct Mapping(&'static str,&'static str);
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impl Neg for Mapping {
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type Output = Vec<Mapping>;
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fn neg(self) -> Vec<Mapping> {
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vec![self.into()]
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}
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}
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impl Sub<Mapping> for Vec<Mapping> {
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type Output=Vec<Mapping>;
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fn sub(mut self, rhs: Mapping) -> Vec<Mapping> {
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self.push(rhs.into());
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self
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}
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}
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fn main() {
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let ver=rustc_version::version_meta();
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let io_commit=match env::var("CORE_IO_COMMIT") {
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Ok(c) => c,
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Err(env::VarError::NotUnicode(_)) => panic!("Invalid commit specified in CORE_IO_COMMIT"),
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Err(env::VarError::NotPresent) => {
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let mappings=include!("mapping.rs");
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let compiler=ver.commit_hash.expect("Couldn't determine compiler version");
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mappings.iter().find(|&&Mapping(elem,_)|elem==compiler).expect("Unknown compiler version, upgrade core_io?").1.to_owned()
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}
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};
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if ver.commit_date.as_ref().map_or(false,|d| &**d>="2018-01-01") {
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println!("cargo:rustc-cfg=core_memchr");
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}
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if ver.commit_date.as_ref().map_or(false,|d| &**d>="2017-06-15") {
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println!("cargo:rustc-cfg=no_collections");
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}
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if ver.commit_date.as_ref().map_or(false,|d| &**d<"2016-12-15") {
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println!("cargo:rustc-cfg=rustc_unicode");
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} else if ver.commit_date.as_ref().map_or(false,|d| &**d<"2017-03-03") {
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println!("cargo:rustc-cfg=std_unicode");
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}
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let mut dest_path=PathBuf::from(env::var_os("OUT_DIR").unwrap());
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dest_path.push("io.rs");
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let mut f=File::create(&dest_path).unwrap();
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let mut target_path=PathBuf::from(env::var_os("CARGO_MANIFEST_DIR").unwrap());
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target_path.push("src");
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target_path.push(io_commit);
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target_path.push("mod.rs");
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f.write_all(br#"#[path=""#).unwrap();
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f.write_all(target_path.into_os_string().into_string().unwrap().as_bytes()).unwrap();
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f.write_all(br#""] mod io;"#).unwrap();
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}
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