1//! This tiny crate checks that the running or installed `rustc` meets some
2//! version requirements. The version is queried by calling the Rust compiler
3//! with `--version`. The path to the compiler is determined first via the
4//! `RUSTC` environment variable. If it is not set, then `rustc` is used. If
5//! that fails, no determination is made, and calls return `None`.
6//!
7//! # Examples
8//!
9//! * Set a `cfg` flag in `build.rs` if the running compiler was determined to
10//! be at least version `1.13.0`:
11//!
12//! ```rust
13//! extern crate version_check as rustc;
14//!
15//! if rustc::is_min_version("1.13.0").unwrap_or(false) {
16//! println!("cargo:rustc-cfg=question_mark_operator");
17//! }
18//! ```
19//!
20//! See [`is_max_version`] or [`is_exact_version`] to check if the compiler
21//! is _at most_ or _exactly_ a certain version.
22//!
23//! * Check that the running compiler was released on or after `2018-12-18`:
24//!
25//! ```rust
26//! extern crate version_check as rustc;
27//!
28//! match rustc::is_min_date("2018-12-18") {
29//! Some(true) => "Yep! It's recent!",
30//! Some(false) => "No, it's older.",
31//! None => "Couldn't determine the rustc version."
32//! };
33//! ```
34//!
35//! See [`is_max_date`] or [`is_exact_date`] to check if the compiler was
36//! released _prior to_ or _exactly on_ a certain date.
37//!
38//! * Check that the running compiler supports feature flags:
39//!
40//! ```rust
41//! extern crate version_check as rustc;
42//!
43//! match rustc::is_feature_flaggable() {
44//! Some(true) => "Yes! It's a dev or nightly release!",
45//! Some(false) => "No, it's stable or beta.",
46//! None => "Couldn't determine the rustc version."
47//! };
48//! ```
49//!
50//! * Check that the running compiler supports a specific feature:
51//!
52//! ```rust
53//! extern crate version_check as rustc;
54//!
55//! if let Some(true) = rustc::supports_feature("doc_cfg") {
56//! println!("cargo:rustc-cfg=has_doc_cfg");
57//! }
58//! ```
59//!
60//! * Check that the running compiler is on the stable channel:
61//!
62//! ```rust
63//! extern crate version_check as rustc;
64//!
65//! match rustc::Channel::read() {
66//! Some(c) if c.is_stable() => format!("Yes! It's stable."),
67//! Some(c) => format!("No, the channel {} is not stable.", c),
68//! None => format!("Couldn't determine the rustc version.")
69//! };
70//! ```
71//!
72//! To interact with the version, release date, and release channel as structs,
73//! use [`Version`], [`Date`], and [`Channel`], respectively. The [`triple()`]
74//! function returns all three values efficiently.
75//!
76//! # Alternatives
77//!
78//! This crate is dead simple with no dependencies. If you need something more
79//! and don't care about panicking if the version cannot be obtained, or if you
80//! don't mind adding dependencies, see
81//! [rustc_version](https://crates.io/crates/rustc_version).
82
83#![allow(deprecated)]
84
85mod version;
86mod channel;
87mod date;
88
89use std::env;
90use std::process::Command;
91
92#[doc(inline)] pub use version::*;
93#[doc(inline)] pub use channel::*;
94#[doc(inline)] pub use date::*;
95
96/// Parses (version, date) as available from rustc version string.
97fn version_and_date_from_rustc_version(s: &str) -> (Option<String>, Option<String>) {
98 let last_line: &str = s.lines().last().unwrap_or(default:s);
99 let mut components: Split<'_, &str> = last_line.trim().split(" ");
100 let version: Option<&str> = components.nth(1);
101 let date: Option<&str> = componentsOption<&str>.filter(|c: &&str| c.ends_with(')')).next()
102 .map(|s: &str| s.trim_right().trim_right_matches(")").trim_left().trim_left_matches('('));
103 (version.map(|s: &str| s.to_string()), date.map(|s: &str| s.to_string()))
104}
105
106/// Parses (version, date) as available from rustc verbose version output.
107fn version_and_date_from_rustc_verbose_version(s: &str) -> (Option<String>, Option<String>) {
108 let (mut version: Option, mut date: Option) = (None, None);
109 for line: &str in s.lines() {
110 let split: impl Fn(&str) -> Option = |s: &str| s.splitn(n:2, pat:":").nth(1).map(|s: &str| s.trim().to_string());
111 match line.trim().split(" ").nth(0) {
112 Some("rustc") => {
113 let (v: Option, d: Option) = version_and_date_from_rustc_version(line);
114 version = version.or(optb:v);
115 date = date.or(optb:d);
116 },
117 Some("release:") => version = split(line),
118 Some("commit-date:") if line.ends_with("unknown") => date = None,
119 Some("commit-date:") => date = split(line),
120 _ => continue
121 }
122 }
123
124 (version, date)
125}
126
127/// Returns (version, date) as available from `rustc --version`.
128fn get_version_and_date() -> Option<(Option<String>, Option<String>)> {
129 let rustc: String = env::var("RUSTC").unwrap_or_else(|_| "rustc".to_string());
130 CommandOption::new(program:rustc).arg("--verbose").arg("--version").output().ok()
131 .and_then(|output: Output| String::from_utf8(vec:output.stdout).ok())
132 .map(|s: String| version_and_date_from_rustc_verbose_version(&s))
133}
134
135/// Reads the triple of [`Version`], [`Channel`], and [`Date`] of the installed
136/// or running `rustc`.
137///
138/// If any attribute cannot be determined (see the [top-level
139/// documentation](crate)), returns `None`.
140///
141/// To obtain only one of three attributes, use [`Version::read()`],
142/// [`Channel::read()`], or [`Date::read()`].
143pub fn triple() -> Option<(Version, Channel, Date)> {
144 let (version_str: String, date_str: String) = match get_version_and_date() {
145 Some((Some(version: String), Some(date: String))) => (version, date),
146 _ => return None
147 };
148
149 // Can't use `?` or `try!` for `Option` in 1.0.0.
150 match Version::parse(&version_str) {
151 Some(version: Version) => match Channel::parse(&version_str) {
152 Some(channel: Channel) => match Date::parse(&date_str) {
153 Some(date: Date) => Some((version, channel, date)),
154 _ => None,
155 },
156 _ => None,
157 },
158 _ => None
159 }
160}
161
162/// Checks that the running or installed `rustc` was released **on or after**
163/// some date.
164///
165/// The format of `min_date` must be YYYY-MM-DD. For instance: `2016-12-20` or
166/// `2017-01-09`.
167///
168/// If the date cannot be retrieved or parsed, or if `min_date` could not be
169/// parsed, returns `None`. Otherwise returns `true` if the installed `rustc`
170/// was release on or after `min_date` and `false` otherwise.
171pub fn is_min_date(min_date: &str) -> Option<bool> {
172 match (Date::read(), Date::parse(min_date)) {
173 (Some(rustc_date: Date), Some(min_date: Date)) => Some(rustc_date >= min_date),
174 _ => None
175 }
176}
177
178/// Checks that the running or installed `rustc` was released **on or before**
179/// some date.
180///
181/// The format of `max_date` must be YYYY-MM-DD. For instance: `2016-12-20` or
182/// `2017-01-09`.
183///
184/// If the date cannot be retrieved or parsed, or if `max_date` could not be
185/// parsed, returns `None`. Otherwise returns `true` if the installed `rustc`
186/// was release on or before `max_date` and `false` otherwise.
187pub fn is_max_date(max_date: &str) -> Option<bool> {
188 match (Date::read(), Date::parse(max_date)) {
189 (Some(rustc_date: Date), Some(max_date: Date)) => Some(rustc_date <= max_date),
190 _ => None
191 }
192}
193
194/// Checks that the running or installed `rustc` was released **exactly** on
195/// some date.
196///
197/// The format of `date` must be YYYY-MM-DD. For instance: `2016-12-20` or
198/// `2017-01-09`.
199///
200/// If the date cannot be retrieved or parsed, or if `date` could not be parsed,
201/// returns `None`. Otherwise returns `true` if the installed `rustc` was
202/// release on `date` and `false` otherwise.
203pub fn is_exact_date(date: &str) -> Option<bool> {
204 match (Date::read(), Date::parse(date)) {
205 (Some(rustc_date: Date), Some(date: Date)) => Some(rustc_date == date),
206 _ => None
207 }
208}
209
210/// Checks that the running or installed `rustc` is **at least** some minimum
211/// version.
212///
213/// The format of `min_version` is a semantic version: `1.3.0`, `1.15.0-beta`,
214/// `1.14.0`, `1.16.0-nightly`, etc.
215///
216/// If the version cannot be retrieved or parsed, or if `min_version` could not
217/// be parsed, returns `None`. Otherwise returns `true` if the installed `rustc`
218/// is at least `min_version` and `false` otherwise.
219pub fn is_min_version(min_version: &str) -> Option<bool> {
220 match (Version::read(), Version::parse(min_version)) {
221 (Some(rustc_ver: Version), Some(min_ver: Version)) => Some(rustc_ver >= min_ver),
222 _ => None
223 }
224}
225
226/// Checks that the running or installed `rustc` is **at most** some maximum
227/// version.
228///
229/// The format of `max_version` is a semantic version: `1.3.0`, `1.15.0-beta`,
230/// `1.14.0`, `1.16.0-nightly`, etc.
231///
232/// If the version cannot be retrieved or parsed, or if `max_version` could not
233/// be parsed, returns `None`. Otherwise returns `true` if the installed `rustc`
234/// is at most `max_version` and `false` otherwise.
235pub fn is_max_version(max_version: &str) -> Option<bool> {
236 match (Version::read(), Version::parse(max_version)) {
237 (Some(rustc_ver: Version), Some(max_ver: Version)) => Some(rustc_ver <= max_ver),
238 _ => None
239 }
240}
241
242/// Checks that the running or installed `rustc` is **exactly** some version.
243///
244/// The format of `version` is a semantic version: `1.3.0`, `1.15.0-beta`,
245/// `1.14.0`, `1.16.0-nightly`, etc.
246///
247/// If the version cannot be retrieved or parsed, or if `version` could not be
248/// parsed, returns `None`. Otherwise returns `true` if the installed `rustc` is
249/// exactly `version` and `false` otherwise.
250pub fn is_exact_version(version: &str) -> Option<bool> {
251 match (Version::read(), Version::parse(version)) {
252 (Some(rustc_ver: Version), Some(version: Version)) => Some(rustc_ver == version),
253 _ => None
254 }
255}
256
257/// Checks whether the running or installed `rustc` supports feature flags.
258///
259/// In other words, if the channel is either "nightly" or "dev".
260///
261/// Note that support for specific `rustc` features can be enabled or disabled
262/// via the `allow-features` compiler flag, which this function _does not_
263/// check. That is, this function _does not_ check whether a _specific_ feature
264/// is supported, but instead whether features are supported at all. To check
265/// for support for a specific feature, use [`supports_feature()`].
266///
267/// If the version could not be determined, returns `None`. Otherwise returns
268/// `true` if the running version supports feature flags and `false` otherwise.
269pub fn is_feature_flaggable() -> Option<bool> {
270 Channel::read().map(|c: Channel| c.supports_features())
271}
272
273/// Checks whether the running or installed `rustc` supports `feature`.
274///
275/// Returns _true_ _iff_ [`is_feature_flaggable()`] returns `true` _and_ the
276/// feature is not disabled via exclusion in `allow-features` via `RUSTFLAGS` or
277/// `CARGO_ENCODED_RUSTFLAGS`. If the version could not be determined, returns
278/// `None`.
279///
280/// # Example
281///
282/// ```rust
283/// use version_check as rustc;
284///
285/// if let Some(true) = rustc::supports_feature("doc_cfg") {
286/// println!("cargo:rustc-cfg=has_doc_cfg");
287/// }
288/// ```
289pub fn supports_feature(feature: &str) -> Option<bool> {
290 match is_feature_flaggable() {
291 Some(true) => { /* continue */ }
292 Some(false) => return Some(false),
293 None => return None,
294 }
295
296 let env_flags = env::var_os("CARGO_ENCODED_RUSTFLAGS")
297 .map(|flags| (flags, '\x1f'))
298 .or_else(|| env::var_os("RUSTFLAGS").map(|flags| (flags, ' ')));
299
300 if let Some((flags, delim)) = env_flags {
301 const ALLOW_FEATURES: &'static str = "allow-features=";
302
303 let rustflags = flags.to_string_lossy();
304 let allow_features = rustflags.split(delim)
305 .map(|flag| flag.trim_left_matches("-Z").trim())
306 .filter(|flag| flag.starts_with(ALLOW_FEATURES))
307 .map(|flag| &flag[ALLOW_FEATURES.len()..]);
308
309 if let Some(allow_features) = allow_features.last() {
310 return Some(allow_features.split(',').any(|f| f.trim() == feature));
311 }
312 }
313
314 // If there are no `RUSTFLAGS` or `CARGO_ENCODED_RUSTFLAGS` or they don't
315 // contain an `allow-features` flag, assume compiler allows all features.
316 Some(true)
317}
318
319#[cfg(test)]
320mod tests {
321 use std::{env, fs};
322
323 use super::version_and_date_from_rustc_version;
324 use super::version_and_date_from_rustc_verbose_version;
325
326 macro_rules! check_parse {
327 (@ $f:expr, $s:expr => $v:expr, $d:expr) => ({
328 if let (Some(v), d) = $f(&$s) {
329 let e_d: Option<&str> = $d.into();
330 assert_eq!((v, d), ($v.to_string(), e_d.map(|s| s.into())));
331 } else {
332 panic!("{:?} didn't parse for version testing.", $s);
333 }
334 });
335 ($f:expr, $s:expr => $v:expr, $d:expr) => ({
336 let warn = "warning: invalid logging spec 'warning', ignoring it";
337 let warn2 = "warning: sorry, something went wrong :(sad)";
338 check_parse!(@ $f, $s => $v, $d);
339 check_parse!(@ $f, &format!("{}\n{}", warn, $s) => $v, $d);
340 check_parse!(@ $f, &format!("{}\n{}", warn2, $s) => $v, $d);
341 check_parse!(@ $f, &format!("{}\n{}\n{}", warn, warn2, $s) => $v, $d);
342 check_parse!(@ $f, &format!("{}\n{}\n{}", warn2, warn, $s) => $v, $d);
343 })
344 }
345
346 macro_rules! check_terse_parse {
347 ($($s:expr => $v:expr, $d:expr,)+) => {$(
348 check_parse!(version_and_date_from_rustc_version, $s => $v, $d);
349 )+}
350 }
351
352 macro_rules! check_verbose_parse {
353 ($($s:expr => $v:expr, $d:expr,)+) => {$(
354 check_parse!(version_and_date_from_rustc_verbose_version, $s => $v, $d);
355 )+}
356 }
357
358 #[test]
359 fn test_version_parse() {
360 check_terse_parse! {
361 "rustc 1.18.0" => "1.18.0", None,
362 "rustc 1.8.0" => "1.8.0", None,
363 "rustc 1.20.0-nightly" => "1.20.0-nightly", None,
364 "rustc 1.20" => "1.20", None,
365 "rustc 1.3" => "1.3", None,
366 "rustc 1" => "1", None,
367 "rustc 1.5.1-beta" => "1.5.1-beta", None,
368 "rustc 1.20.0 (2017-07-09)" => "1.20.0", Some("2017-07-09"),
369 "rustc 1.20.0-dev (2017-07-09)" => "1.20.0-dev", Some("2017-07-09"),
370 "rustc 1.20.0-nightly (d84693b93 2017-07-09)" => "1.20.0-nightly", Some("2017-07-09"),
371 "rustc 1.20.0 (d84693b93 2017-07-09)" => "1.20.0", Some("2017-07-09"),
372 "rustc 1.30.0-nightly (3bc2ca7e4 2018-09-20)" => "1.30.0-nightly", Some("2018-09-20"),
373 };
374 }
375
376 #[test]
377 fn test_verbose_version_parse() {
378 check_verbose_parse! {
379 "rustc 1.0.0 (a59de37e9 2015-05-13) (built 2015-05-14)\n\
380 binary: rustc\n\
381 commit-hash: a59de37e99060162a2674e3ff45409ac73595c0e\n\
382 commit-date: 2015-05-13\n\
383 build-date: 2015-05-14\n\
384 host: x86_64-unknown-linux-gnu\n\
385 release: 1.0.0" => "1.0.0", Some("2015-05-13"),
386
387 "rustc 1.0.0 (a59de37e9 2015-05-13) (built 2015-05-14)\n\
388 commit-hash: a59de37e99060162a2674e3ff45409ac73595c0e\n\
389 commit-date: 2015-05-13\n\
390 build-date: 2015-05-14\n\
391 host: x86_64-unknown-linux-gnu\n\
392 release: 1.0.0" => "1.0.0", Some("2015-05-13"),
393
394 "rustc 1.50.0 (cb75ad5db 2021-02-10)\n\
395 binary: rustc\n\
396 commit-hash: cb75ad5db02783e8b0222fee363c5f63f7e2cf5b\n\
397 commit-date: 2021-02-10\n\
398 host: x86_64-unknown-linux-gnu\n\
399 release: 1.50.0" => "1.50.0", Some("2021-02-10"),
400
401 "rustc 1.52.0-nightly (234781afe 2021-03-07)\n\
402 binary: rustc\n\
403 commit-hash: 234781afe33d3f339b002f85f948046d8476cfc9\n\
404 commit-date: 2021-03-07\n\
405 host: x86_64-unknown-linux-gnu\n\
406 release: 1.52.0-nightly\n\
407 LLVM version: 12.0.0" => "1.52.0-nightly", Some("2021-03-07"),
408
409 "rustc 1.41.1\n\
410 binary: rustc\n\
411 commit-hash: unknown\n\
412 commit-date: unknown\n\
413 host: x86_64-unknown-linux-gnu\n\
414 release: 1.41.1\n\
415 LLVM version: 7.0" => "1.41.1", None,
416
417 "rustc 1.49.0\n\
418 binary: rustc\n\
419 commit-hash: unknown\n\
420 commit-date: unknown\n\
421 host: x86_64-unknown-linux-gnu\n\
422 release: 1.49.0" => "1.49.0", None,
423
424 "rustc 1.50.0 (Fedora 1.50.0-1.fc33)\n\
425 binary: rustc\n\
426 commit-hash: unknown\n\
427 commit-date: unknown\n\
428 host: x86_64-unknown-linux-gnu\n\
429 release: 1.50.0" => "1.50.0", None,
430 };
431 }
432
433 fn read_static(verbose: bool, channel: &str, minor: usize) -> String {
434 use std::fs::File;
435 use std::path::Path;
436 use std::io::{BufReader, Read};
437
438 let subdir = if verbose { "verbose" } else { "terse" };
439 let path = Path::new(STATIC_PATH)
440 .join(channel)
441 .join(subdir)
442 .join(format!("rustc-1.{}.0", minor));
443
444 let file = File::open(path).unwrap();
445 let mut buf_reader = BufReader::new(file);
446 let mut contents = String::new();
447 buf_reader.read_to_string(&mut contents).unwrap();
448 contents
449 }
450
451 static STATIC_PATH: &'static str = concat!(env!("CARGO_MANIFEST_DIR"), "/static");
452
453 static DATES: [&'static str; 51] = [
454 "2015-05-13", "2015-06-19", "2015-08-03", "2015-09-15", "2015-10-27",
455 "2015-12-04", "2016-01-19", "2016-02-29", "2016-04-11", "2016-05-18",
456 "2016-07-03", "2016-08-15", "2016-09-23", "2016-11-07", "2016-12-16",
457 "2017-01-19", "2017-03-10", "2017-04-24", "2017-06-06", "2017-07-17",
458 "2017-08-27", "2017-10-09", "2017-11-20", "2018-01-01", "2018-02-12",
459 "2018-03-25", "2018-05-07", "2018-06-19", "2018-07-30", "2018-09-11",
460 "2018-10-24", "2018-12-04", "2019-01-16", "2019-02-28", "2019-04-10",
461 "2019-05-20", "2019-07-03", "2019-08-13", "2019-09-23", "2019-11-04",
462 "2019-12-16", "2020-01-27", "2020-03-09", "2020-04-20", "2020-06-01",
463 "2020-07-13", "2020-08-24", "2020-10-07", "2020-11-16", "2020-12-29",
464 "2021-02-10",
465 ];
466
467 #[test]
468 fn test_stable_compatibility() {
469 if env::var_os("FORCE_STATIC").is_none() && fs::metadata(STATIC_PATH).is_err() {
470 // We exclude `/static` when we package `version_check`, so don't
471 // run if static files aren't present unless we know they should be.
472 return;
473 }
474
475 // Ensure we can parse all output from all Linux stable releases.
476 for v in 0..DATES.len() {
477 let (version, date) = (&format!("1.{}.0", v), Some(DATES[v]));
478 check_terse_parse!(read_static(false, "stable", v) => version, date,);
479 check_verbose_parse!(read_static(true, "stable", v) => version, date,);
480 }
481 }
482
483 #[test]
484 fn test_parse_current() {
485 let (version, channel) = (::Version::read(), ::Channel::read());
486 assert!(version.is_some());
487 assert!(channel.is_some());
488
489 if let Ok(known_channel) = env::var("KNOWN_CHANNEL") {
490 assert_eq!(channel, ::Channel::parse(&known_channel));
491 }
492 }
493}
494