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