//! Contains code for selecting features
#![deny(missing_docs)]
#![deny(warnings)]
#![deny(unused_extern_crates)]
use std::io;
use std::str::FromStr;
/// Define RustTarget struct definition, Default impl, and conversions
/// between RustTarget and String.
macro_rules! rust_target_def {
( $( $( #[$attr:meta] )* => $release:ident => $value:expr; )* ) => {
/// Represents the version of the Rust language to target.
///
/// To support a beta release, use the corresponding stable release.
///
/// This enum will have more variants added as necessary.
#[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Hash)]
#[allow(non_camel_case_types)]
pub enum RustTarget {
$(
$(
#[$attr]
)*
$release,
)*
}
impl Default for RustTarget {
/// Gives the latest stable Rust version
fn default() -> RustTarget {
LATEST_STABLE_RUST
}
}
impl FromStr for RustTarget {
type Err = io::Error;
/// Create a `RustTarget` from a string.
///
/// * The stable/beta versions of Rust are of the form "1.0",
/// "1.19", etc.
/// * The nightly version should be specified with "nightly".
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s.as_ref() {
$(
stringify!($value) => Ok(RustTarget::$release),
)*
_ => Err(
io::Error::new(
io::ErrorKind::InvalidInput,
concat!(
"Got an invalid rust target. Accepted values ",
"are of the form ",
"\"1.0\" or \"nightly\"."))),
}
}
}
impl From<RustTarget> for String {
fn from(target: RustTarget) -> Self {
match target {
$(
RustTarget::$release => stringify!($value),
)*
}.into()
}
}
}
}
/// Defines an array slice with all RustTarget values
macro_rules! rust_target_values_def {
( $( $( #[$attr:meta] )* => $release:ident => $value:expr; )* ) => {
/// Strings of allowed `RustTarget` values
pub static RUST_TARGET_STRINGS: &'static [&str] = &[
$(
stringify!($value),
)*
];
}
}
/// Defines macro which takes a macro
macro_rules! rust_target_base {
( $x_macro:ident ) => {
$x_macro!(
/// Rust stable 1.0
=> Stable_1_0 => 1.0;
/// Rust stable 1.19
=> Stable_1_19 => 1.19;
/// Rust stable 1.20
=> Stable_1_20 => 1.20;
/// Rust stable 1.21
=> Stable_1_21 => 1.21;
/// Rust stable 1.25
=> Stable_1_25 => 1.25;
/// Rust stable 1.26
=> Stable_1_26 => 1.26;
/// Rust stable 1.27
=> Stable_1_27 => 1.27;
/// Rust stable 1.28
=> Stable_1_28 => 1.28;
/// Rust stable 1.30
=> Stable_1_30 => 1.30;
/// Rust stable 1.33
=> Stable_1_33 => 1.33;
/// Nightly rust
=> Nightly => nightly;
);
}
}
rust_target_base!(rust_target_def);
rust_target_base!(rust_target_values_def);
/// Latest stable release of Rust
pub const LATEST_STABLE_RUST: RustTarget = RustTarget::Stable_1_33;
/// Create RustFeatures struct definition, new(), and a getter for each field
macro_rules! rust_feature_def {
(
$( $rust_target:ident {
$( $( #[$attr:meta] )* => $feature:ident; )*
} )*
) => {
/// Features supported by a rust target
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub struct RustFeatures {
$( $(
$(
#[$attr]
)*
pub $feature: bool,
)* )*
}
impl RustFeatures {
/// Gives a RustFeatures struct with all features disabled
fn new() -> Self {
RustFeatures {
$( $(
$feature: false,
)* )*
}
}
}
impl From<RustTarget> for RustFeatures {
fn from(rust_target: RustTarget) -> Self {
let mut features = RustFeatures::new();
$(
if rust_target >= RustTarget::$rust_target {
$(
features.$feature = true;
)*
}
)*
features
}
}
}
}
rust_feature_def!(
Stable_1_19 {
/// Untagged unions ([RFC 1444](https://github.com/rust-lang/rfcs/blob/master/text/1444-union.md))
=> untagged_union;
}
Stable_1_20 {
/// associated constants ([PR](https://github.com/rust-lang/rust/pull/42809))
=> associated_const;
}
Stable_1_21 {
/// builtin impls for `Clone` ([PR](https://github.com/rust-lang/rust/pull/43690))
=> builtin_clone_impls;
}
Stable_1_25 {
/// repr(align) ([PR](https://github.com/rust-lang/rust/pull/47006))
=> repr_align;
}
Stable_1_26 {
/// [i128 / u128 support](https://doc.rust-lang.org/std/primitive.i128.html)
=> i128_and_u128;
}
Stable_1_27 {
/// `must_use` attribute on functions ([PR](https://github.com/rust-lang/rust/pull/48925))
=> must_use_function;
}
Stable_1_28 {
/// repr(transparent) ([PR](https://github.com/rust-lang/rust/pull/51562))
=> repr_transparent;
}
Stable_1_30 {
/// `const fn` support for limited cases
/// ([PR](https://github.com/rust-lang/rust/pull/54835/)
=> min_const_fn;
}
Stable_1_33 {
/// repr(packed(N)) ([PR](https://github.com/rust-lang/rust/pull/57049))
=> repr_packed_n;
}
Nightly {
/// `thiscall` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/42202))
=> thiscall_abi;
/// `non_exhaustive` enums/structs ([Tracking issue](https://github.com/rust-lang/rust/issues/44109))
=> non_exhaustive;
}
);
impl Default for RustFeatures {
fn default() -> Self {
let default_rust_target: RustTarget = Default::default();
Self::from(default_rust_target)
}
}
#[cfg(test)]
mod test {
#![allow(unused_imports)]
use super::*;
#[test]
fn target_features() {
let f_1_0 = RustFeatures::from(RustTarget::Stable_1_0);
assert!(
!f_1_0.untagged_union
&& !f_1_0.associated_const
&& !f_1_0.builtin_clone_impls
&& !f_1_0.repr_align
&& !f_1_0.thiscall_abi
);
let f_1_21 = RustFeatures::from(RustTarget::Stable_1_21);
assert!(
f_1_21.untagged_union
&& f_1_21.associated_const
&& f_1_21.builtin_clone_impls
&& !f_1_21.repr_align
&& !f_1_21.thiscall_abi
);
let f_nightly = RustFeatures::from(RustTarget::Nightly);
assert!(
f_nightly.untagged_union
&& f_nightly.associated_const
&& f_nightly.builtin_clone_impls
&& f_nightly.repr_align
&& f_nightly.thiscall_abi
);
}
fn test_target(target_str: &str, target: RustTarget) {
let target_string: String = target.into();
assert_eq!(target_str, target_string);
assert_eq!(target, RustTarget::from_str(target_str).unwrap());
}
#[test]
fn str_to_target() {
test_target("1.0", RustTarget::Stable_1_0);
test_target("1.19", RustTarget::Stable_1_19);
test_target("1.21", RustTarget::Stable_1_21);
test_target("1.25", RustTarget::Stable_1_25);
test_target("nightly", RustTarget::Nightly);
}
}