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Diffstat (limited to 'third_party/rust/version_check/src/lib.rs')
| -rw-r--r-- | third_party/rust/version_check/src/lib.rs | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/third_party/rust/version_check/src/lib.rs b/third_party/rust/version_check/src/lib.rs new file mode 100644 index 0000000000..6df728e25a --- /dev/null +++ b/third_party/rust/version_check/src/lib.rs @@ -0,0 +1,288 @@ +//! This tiny crate checks that the running or installed `rustc` meets some +//! version requirements. The version is queried by calling the Rust compiler +//! with `--version`. The path to the compiler is determined first via the +//! `RUSTC` environment variable. If it is not set, then `rustc` is used. If +//! that fails, no determination is made, and calls return `None`. +//! +//! # Examples +//! +//! Set a `cfg` flag in `build.rs` if the running compiler was determined to be +//! at least version `1.13.0`: +//! +//! ```rust +//! extern crate version_check as rustc; +//! +//! if rustc::is_min_version("1.13.0").unwrap_or(false) { +//! println!("cargo:rustc-cfg=question_mark_operator"); +//! } +//! ``` +//! +//! See [`is_max_version`] or [`is_exact_version`] to check if the compiler +//! is _at most_ or _exactly_ a certain version. +//! +//! Check that the running compiler was released on or after `2018-12-18`: +//! +//! ```rust +//! extern crate version_check as rustc; +//! +//! match rustc::is_min_date("2018-12-18") { +//! Some(true) => "Yep! It's recent!", +//! Some(false) => "No, it's older.", +//! None => "Couldn't determine the rustc version." +//! }; +//! ``` +//! +//! See [`is_max_date`] or [`is_exact_date`] to check if the compiler was +//! released _prior to_ or _exactly on_ a certain date. +//! +//! Check that the running compiler supports feature flags: +//! +//! ```rust +//! extern crate version_check as rustc; +//! +//! match rustc::is_feature_flaggable() { +//! Some(true) => "Yes! It's a dev or nightly release!", +//! Some(false) => "No, it's stable or beta.", +//! None => "Couldn't determine the rustc version." +//! }; +//! ``` +//! +//! Check that the running compiler is on the stable channel: +//! +//! ```rust +//! extern crate version_check as rustc; +//! +//! match rustc::Channel::read() { +//! Some(c) if c.is_stable() => format!("Yes! It's stable."), +//! Some(c) => format!("No, the channel {} is not stable.", c), +//! None => format!("Couldn't determine the rustc version.") +//! }; +//! ``` +//! +//! To interact with the version, release date, and release channel as structs, +//! use [`Version`], [`Date`], and [`Channel`], respectively. The [`triple()`] +//! function returns all three values efficiently. +//! +//! # Alternatives +//! +//! This crate is dead simple with no dependencies. If you need something more +//! and don't care about panicking if the version cannot be obtained, or if you +//! don't mind adding dependencies, see +//! [rustc_version](https://crates.io/crates/rustc_version). + +#![allow(deprecated)] + +mod version; +mod channel; +mod date; + +use std::env; +use std::process::Command; + +#[doc(inline)] pub use version::*; +#[doc(inline)] pub use channel::*; +#[doc(inline)] pub use date::*; + +/// Parses (version, date) as available from rustc version string. +fn version_and_date_from_rustc_version(s: &str) -> (Option<String>, Option<String>) { + let last_line = s.lines().last().unwrap_or(s); + let mut components = last_line.trim().split(" "); + let version = components.nth(1); + let date = components.filter(|c| c.ends_with(')')).next() + .map(|s| s.trim_right().trim_right_matches(")").trim_left().trim_left_matches('(')); + (version.map(|s| s.to_string()), date.map(|s| s.to_string())) +} + +/// Returns (version, date) as available from `rustc --version`. +fn get_version_and_date() -> Option<(Option<String>, Option<String>)> { + env::var("RUSTC").ok() + .and_then(|rustc| Command::new(rustc).arg("--version").output().ok()) + .or_else(|| Command::new("rustc").arg("--version").output().ok()) + .and_then(|output| String::from_utf8(output.stdout).ok()) + .map(|s| version_and_date_from_rustc_version(&s)) +} + +/// Reads the triple of [`Version`], [`Channel`], and [`Date`] of the installed +/// or running `rustc`. +/// +/// If any attribute cannot be determined (see the [top-level +/// documentation](crate)), returns `None`. +/// +/// To obtain only one of three attributes, use [`Version::read()`], +/// [`Channel::read()`], or [`Date::read()`]. +pub fn triple() -> Option<(Version, Channel, Date)> { + let (version_str, date_str) = match get_version_and_date() { + Some((Some(version), Some(date))) => (version, date), + _ => return None + }; + + // Can't use `?` or `try!` for `Option` in 1.0.0. + match Version::parse(&version_str) { + Some(version) => match Channel::parse(&version_str) { + Some(channel) => match Date::parse(&date_str) { + Some(date) => Some((version, channel, date)), + _ => None, + }, + _ => None, + }, + _ => None + } +} + +/// Checks that the running or installed `rustc` was released **on or after** +/// some date. +/// +/// The format of `min_date` must be YYYY-MM-DD. For instance: `2016-12-20` or +/// `2017-01-09`. +/// +/// If the date cannot be retrieved or parsed, or if `min_date` could not be +/// parsed, returns `None`. Otherwise returns `true` if the installed `rustc` +/// was release on or after `min_date` and `false` otherwise. +pub fn is_min_date(min_date: &str) -> Option<bool> { + match (Date::read(), Date::parse(min_date)) { + (Some(rustc_date), Some(min_date)) => Some(rustc_date >= min_date), + _ => None + } +} + +/// Checks that the running or installed `rustc` was released **on or before** +/// some date. +/// +/// The format of `max_date` must be YYYY-MM-DD. For instance: `2016-12-20` or +/// `2017-01-09`. +/// +/// If the date cannot be retrieved or parsed, or if `max_date` could not be +/// parsed, returns `None`. Otherwise returns `true` if the installed `rustc` +/// was release on or before `max_date` and `false` otherwise. +pub fn is_max_date(max_date: &str) -> Option<bool> { + match (Date::read(), Date::parse(max_date)) { + (Some(rustc_date), Some(max_date)) => Some(rustc_date <= max_date), + _ => None + } +} + +/// Checks that the running or installed `rustc` was released **exactly** on +/// some date. +/// +/// The format of `date` must be YYYY-MM-DD. For instance: `2016-12-20` or +/// `2017-01-09`. +/// +/// If the date cannot be retrieved or parsed, or if `date` could not be parsed, +/// returns `None`. Otherwise returns `true` if the installed `rustc` was +/// release on `date` and `false` otherwise. +pub fn is_exact_date(date: &str) -> Option<bool> { + match (Date::read(), Date::parse(date)) { + (Some(rustc_date), Some(date)) => Some(rustc_date == date), + _ => None + } +} + +/// Checks that the running or installed `rustc` is **at least** some minimum +/// version. +/// +/// The format of `min_version` is a semantic version: `1.3.0`, `1.15.0-beta`, +/// `1.14.0`, `1.16.0-nightly`, etc. +/// +/// If the version cannot be retrieved or parsed, or if `min_version` could not +/// be parsed, returns `None`. Otherwise returns `true` if the installed `rustc` +/// is at least `min_version` and `false` otherwise. +pub fn is_min_version(min_version: &str) -> Option<bool> { + match (Version::read(), Version::parse(min_version)) { + (Some(rustc_ver), Some(min_ver)) => Some(rustc_ver >= min_ver), + _ => None + } +} + +/// Checks that the running or installed `rustc` is **at most** some maximum +/// version. +/// +/// The format of `max_version` is a semantic version: `1.3.0`, `1.15.0-beta`, +/// `1.14.0`, `1.16.0-nightly`, etc. +/// +/// If the version cannot be retrieved or parsed, or if `max_version` could not +/// be parsed, returns `None`. Otherwise returns `true` if the installed `rustc` +/// is at most `max_version` and `false` otherwise. +pub fn is_max_version(max_version: &str) -> Option<bool> { + match (Version::read(), Version::parse(max_version)) { + (Some(rustc_ver), Some(max_ver)) => Some(rustc_ver <= max_ver), + _ => None + } +} + +/// Checks that the running or installed `rustc` is **exactly** some version. +/// +/// The format of `version` is a semantic version: `1.3.0`, `1.15.0-beta`, +/// `1.14.0`, `1.16.0-nightly`, etc. +/// +/// If the version cannot be retrieved or parsed, or if `version` could not be +/// parsed, returns `None`. Otherwise returns `true` if the installed `rustc` is +/// exactly `version` and `false` otherwise. +pub fn is_exact_version(version: &str) -> Option<bool> { + match (Version::read(), Version::parse(version)) { + (Some(rustc_ver), Some(version)) => Some(rustc_ver == version), + _ => None + } +} + +/// Checks whether the running or installed `rustc` supports feature flags. +/// +/// In other words, if the channel is either "nightly" or "dev". +/// +/// If the version could not be determined, returns `None`. Otherwise returns +/// `true` if the running version supports feature flags and `false` otherwise. +pub fn is_feature_flaggable() -> Option<bool> { + Channel::read().map(|c| c.supports_features()) +} + +#[cfg(test)] +mod tests { + use super::version_and_date_from_rustc_version; + + macro_rules! check_parse { + ($s:expr => $v:expr, $d:expr) => ( + if let (Some(v), d) = version_and_date_from_rustc_version($s) { + let e_d: Option<&str> = $d.into(); + assert_eq!((v, d), ($v.into(), e_d.map(|s| s.into()))); + } else { + panic!("{:?} didn't parse for version testing.", $s); + } + ) + } + + #[test] + fn test_version_parse() { + check_parse!("rustc 1.18.0" => "1.18.0", None); + check_parse!("rustc 1.8.0" => "1.8.0", None); + check_parse!("rustc 1.20.0-nightly" => "1.20.0-nightly", None); + check_parse!("rustc 1.20" => "1.20", None); + check_parse!("rustc 1.3" => "1.3", None); + check_parse!("rustc 1" => "1", None); + check_parse!("rustc 1.5.1-beta" => "1.5.1-beta", None); + + // Because of 1.0.0, we can't use Option<T>: From<T>. + check_parse!("rustc 1.20.0 (2017-07-09)" + => "1.20.0", Some("2017-07-09")); + + check_parse!("rustc 1.20.0-dev (2017-07-09)" + => "1.20.0-dev", Some("2017-07-09")); + + check_parse!("rustc 1.20.0-nightly (d84693b93 2017-07-09)" + => "1.20.0-nightly", Some("2017-07-09")); + + check_parse!("rustc 1.20.0 (d84693b93 2017-07-09)" + => "1.20.0", Some("2017-07-09")); + + check_parse!("warning: invalid logging spec 'warning', ignoring it + rustc 1.30.0-nightly (3bc2ca7e4 2018-09-20)" + => "1.30.0-nightly", Some("2018-09-20")); + + check_parse!("warning: invalid logging spec 'warning', ignoring it\n + rustc 1.30.0-nightly (3bc2ca7e4 2018-09-20)" + => "1.30.0-nightly", Some("2018-09-20")); + + check_parse!("warning: invalid logging spec 'warning', ignoring it + warning: something else went wrong + rustc 1.30.0-nightly (3bc2ca7e4 2018-09-20)" + => "1.30.0-nightly", Some("2018-09-20")); + } +} |