rust/crates/ra_cfg/src/lib.rs
2019-11-12 15:41:02 +03:00

57 lines
1.9 KiB
Rust

//! ra_cfg defines conditional compiling options, `cfg` attibute parser and evaluator
mod cfg_expr;
use std::iter::IntoIterator;
use ra_syntax::SmolStr;
use rustc_hash::FxHashSet;
pub use cfg_expr::{parse_cfg, CfgExpr};
/// Configuration options used for conditional compilition on items with `cfg` attributes.
/// We have two kind of options in different namespaces: atomic options like `unix`, and
/// key-value options like `target_arch="x86"`.
///
/// Note that for key-value options, one key can have multiple values (but not none).
/// `feature` is an example. We have both `feature="foo"` and `feature="bar"` if features
/// `foo` and `bar` are both enabled. And here, we store key-value options as a set of tuple
/// of key and value in `key_values`.
///
/// See: https://doc.rust-lang.org/reference/conditional-compilation.html#set-configuration-options
#[derive(Debug, Clone, PartialEq, Eq, Default)]
pub struct CfgOptions {
atoms: FxHashSet<SmolStr>,
key_values: FxHashSet<(SmolStr, SmolStr)>,
}
impl CfgOptions {
pub fn check(&self, cfg: &CfgExpr) -> Option<bool> {
cfg.fold(&|key, value| match value {
None => self.atoms.contains(key),
Some(value) => self.key_values.contains(&(key.clone(), value.clone())),
})
}
pub fn is_cfg_enabled(&self, attr: &tt::Subtree) -> Option<bool> {
self.check(&parse_cfg(attr))
}
pub fn insert_atom(&mut self, key: SmolStr) {
self.atoms.insert(key);
}
pub fn remove_atom(&mut self, name: &str) {
self.atoms.remove(name);
}
pub fn insert_key_value(&mut self, key: SmolStr, value: SmolStr) {
self.key_values.insert((key, value));
}
/// Shortcut to set features
pub fn insert_features(&mut self, iter: impl IntoIterator<Item = SmolStr>) {
iter.into_iter().for_each(|feat| self.insert_key_value("feature".into(), feat));
}
}