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pub mod lexer;
mod parser;
use smallvec::SmallVec;
/// A predicate function, used to combine 1 or more predicates
/// into a single value
#[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Copy, Clone)]
pub enum Func {
/// `not()` with a configuration predicate. It is true if its predicate
/// is false and false if its predicate is true.
Not,
/// `all()` with a comma separated list of configuration predicates. It
/// is false if at least one predicate is false. If there are no predicates,
/// it is true.
All,
/// `any()` with a comma separated list of configuration predicates. It
/// is true if at least one predicate is true. If there are no predicates,
/// it is false.
Any,
}
use crate::targets as targ;
/// All predicates that pertains to a target, except for `target_feature`
#[derive(Clone, Copy, PartialEq, Debug)]
pub enum TargetPredicate {
/// [target_arch](https://doc.rust-lang.org/reference/conditional-compilation.html#target_arch)
Arch(targ::Arch),
/// [target_endian](https://doc.rust-lang.org/reference/conditional-compilation.html#target_endian)
Endian(targ::Endian),
/// [target_env](https://doc.rust-lang.org/reference/conditional-compilation.html#target_env)
Env(Option<targ::Env>),
/// [target_family](https://doc.rust-lang.org/reference/conditional-compilation.html#target_family)
/// This also applies to the bare [`unix` and `windows`](https://doc.rust-lang.org/reference/conditional-compilation.html#unix-and-windows)
/// predicates.
Family(Option<targ::Family>),
/// [target_os](https://doc.rust-lang.org/reference/conditional-compilation.html#target_os)
Os(Option<targ::Os>),
/// [target_pointer_width](https://doc.rust-lang.org/reference/conditional-compilation.html#target_pointer_width)
PointerWidth(u8),
/// [target_vendor](https://doc.rust-lang.org/reference/conditional-compilation.html#target_vendor)
Vendor(Option<targ::Vendor>),
}
impl TargetPredicate {
/// Returns true of the predicate matches the specified target
///
/// ```
/// use cfg_expr::{targets::*, expr::TargetPredicate as tp};
/// let win = get_target_by_triple("x86_64-pc-windows-msvc").unwrap();
///
/// assert!(
/// tp::Arch(Arch::x86_64).matches(win) &&
/// tp::Endian(Endian::little).matches(win) &&
/// tp::Env(Some(Env::msvc)).matches(win) &&
/// tp::Family(Some(Family::windows)).matches(win) &&
/// tp::Os(Some(Os::windows)).matches(win) &&
/// tp::PointerWidth(64).matches(win) &&
/// tp::Vendor(Some(Vendor::pc)).matches(win)
/// );
/// ```
pub fn matches(self, target: &targ::TargetInfo) -> bool {
use TargetPredicate::*;
match self {
Arch(a) => a == target.arch,
Endian(end) => end == target.endian,
Env(env) => env == target.env,
Family(fam) => fam == target.family,
Os(os) => os == target.os,
PointerWidth(w) => w == target.pointer_width,
Vendor(ven) => ven == target.vendor,
}
}
}
/// A single predicate in a `cfg()` expression
#[derive(Debug, PartialEq)]
pub enum Predicate<'a> {
/// A target predicate, with the `target_` prefix
Target(TargetPredicate),
/// Whether rustc's test harness is [enabled](https://doc.rust-lang.org/reference/conditional-compilation.html#test)
Test,
/// [Enabled](https://doc.rust-lang.org/reference/conditional-compilation.html#debug_assertions)
/// when compiling without optimizations.
DebugAssertions,
/// [Enabled](https://doc.rust-lang.org/reference/conditional-compilation.html#proc_macro) for
/// crates of the proc_macro type.
ProcMacro,
/// A [`feature = "<name>"`](https://doc.rust-lang.org/nightly/cargo/reference/features.html)
Feature(&'a str),
/// [target_feature](https://doc.rust-lang.org/reference/conditional-compilation.html#target_feature)
TargetFeature(&'a str),
/// A generic bare predicate key that doesn't match one of the known options, eg `cfg(bare)`
Flag(&'a str),
/// A generic key = "value" predicate that doesn't match one of the known options, eg `cfg(foo = "bar")`
KeyValue { key: &'a str, val: &'a str },
}
#[derive(Clone, PartialEq, Debug)]
pub(crate) enum InnerPredicate {
Target(TargetPredicate),
Test,
DebugAssertions,
ProcMacro,
Feature(std::ops::Range<usize>),
TargetFeature(std::ops::Range<usize>),
Other {
identifier: std::ops::Range<usize>,
value: Option<std::ops::Range<usize>>,
},
}
impl InnerPredicate {
fn to_pred<'a>(&self, s: &'a str) -> Predicate<'a> {
use InnerPredicate as IP;
use Predicate::*;
match self {
IP::Target(tp) => Target(*tp),
IP::Test => Test,
IP::DebugAssertions => DebugAssertions,
IP::ProcMacro => ProcMacro,
IP::Feature(rng) => Feature(&s[rng.clone()]),
IP::TargetFeature(rng) => TargetFeature(&s[rng.clone()]),
IP::Other { identifier, value } => match value {
Some(vs) => KeyValue {
key: &s[identifier.clone()],
val: &s[vs.clone()],
},
None => Flag(&s[identifier.clone()]),
},
}
}
}
#[derive(Clone, PartialEq, Debug)]
pub(crate) enum ExprNode {
Fn(Func),
Predicate(InnerPredicate),
}
/// A parsed `cfg()` expression that can evaluated
#[derive(Debug)]
pub struct Expression {
pub(crate) expr: SmallVec<[ExprNode; 5]>,
// We keep the original string around for providing the arbitrary
// strings that can make up an expression
pub(crate) original: String,
}
impl Expression {
/// An iterator over each predicate in the expression
pub fn predicates(&self) -> impl Iterator<Item = Predicate<'_>> {
self.expr.iter().filter_map(move |item| match item {
ExprNode::Predicate(pred) => {
let pred = pred.clone().to_pred(&self.original);
Some(pred)
}
_ => None,
})
}
/// Evaluates the expression, using the provided closure to determine the value of
/// each predicate, which are then combined into a final result depending on the
/// functions not(), all(), or any() in the expression
///
/// ```
/// use cfg_expr::{targets::*, Expression, Predicate};
///
/// let linux_musl = get_target_by_triple("x86_64-unknown-linux-musl").unwrap();
///
/// let expr = Expression::parse(r#"all(not(windows), target_env = "musl", any(target_arch = "x86", target_arch = "x86_64"))"#).unwrap();
///
/// assert!(expr.eval(|pred| {
/// match pred {
/// Predicate::Target(tp) => tp.matches(linux_musl),
/// _ => false,
/// }
/// }));
/// ```
pub fn eval<EP: FnMut(&Predicate<'_>) -> bool>(&self, mut eval_predicate: EP) -> bool {
let mut result_stack = SmallVec::<[bool; 8]>::new();
// We store the expression as postfix, so just evaluate each license
// requirement in the order it comes, and then combining the previous
// results according to each operator as it comes
for node in self.expr.iter() {
match node {
ExprNode::Predicate(pred) => {
let pred = pred.to_pred(&self.original);
result_stack.push(eval_predicate(&pred));
}
ExprNode::Fn(Func::All) => {
// all() with a comma separated list of configuration predicates.
// It is false if at least one predicate is false.
// If there are no predicates, it is true.
let mut result = true;
while let Some(rs) = result_stack.pop() {
result = result && rs;
}
result_stack.push(result);
}
ExprNode::Fn(Func::Any) => {
// any() with a comma separated list of configuration predicates.
// It is true if at least one predicate is true.
// If there are no predicates, it is false.
let mut result = false;
while let Some(rs) = result_stack.pop() {
result = result || rs;
}
result_stack.push(result);
}
ExprNode::Fn(Func::Not) => {
// not() with a configuration predicate.
// It is true if its predicate is false
// and false if its predicate is true.
let r = result_stack.pop().unwrap();
result_stack.push(!r);
}
}
}
result_stack.pop().unwrap()
}
}