mirror of https://github.com/rust-lang/rust
57 lines
1.7 KiB
Rust
57 lines
1.7 KiB
Rust
//@ force-host
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//@ no-prefer-dynamic
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#![crate_type = "proc-macro"]
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extern crate proc_macro;
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use proc_macro::{TokenStream, TokenTree as Tt};
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use std::str::FromStr;
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// String containing the current version number of the tip, i.e. "1.41.2"
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static VERSION_NUMBER: &str = include_str!("../../../../../src/version");
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#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord)]
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struct Version {
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major: i16,
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minor: i16,
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patch: i16,
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}
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fn parse_version(s: &str) -> Option<Version> {
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let mut digits = s.splitn(3, '.');
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let major = digits.next()?.parse().ok()?;
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let minor = digits.next()?.parse().ok()?;
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let patch = digits.next().unwrap_or("0").trim().parse().ok()?;
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Some(Version { major, minor, patch })
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}
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#[proc_macro_attribute]
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/// Emits a #[cfg(version)] relative to the current one, so passing
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/// -1 as argument on compiler 1.50 will emit #[cfg(version("1.49.0"))],
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/// while 1 will emit #[cfg(version("1.51.0"))]
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pub fn ver_cfg_rel(attr: TokenStream, input: TokenStream) -> TokenStream {
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let mut v_rel = None;
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for a in attr.into_iter() {
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match a {
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Tt::Literal(l) => {
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let mut s = l.to_string();
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let s = s.trim_matches('"');
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let v: i16 = s.parse().unwrap();
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v_rel = Some(v);
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break;
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},
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_ => panic!("{:?}", a),
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}
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}
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let v_rel = v_rel.unwrap();
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let mut v = parse_version(VERSION_NUMBER).unwrap();
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v.minor += v_rel;
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let attr_str = format!("#[cfg(version(\"{}.{}.{}\"))]", v.major, v.minor, v.patch);
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let mut res = Vec::<Tt>::new();
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res.extend(TokenStream::from_str(&attr_str).unwrap().into_iter());
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res.extend(input.into_iter());
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res.into_iter().collect()
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}
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