Simplify cfg representation

2 files changed, 37 insertions, 29 deletions

diff --git a/crates/cfg/src/cfg_expr.rs b/crates/cfg/src/cfg_expr.rs
index 336fe25bc..db3655b74 100644
--- a/crates/cfg/src/cfg_expr.rs
+++ b/crates/cfg/src/cfg_expr.rs
@@ -6,26 +6,42 @@ use std::slice::Iter as SliceIter;
 
 use tt::SmolStr;
 
+/// A simple configuration value passed in from the outside.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum CfgAtom {
+    /// eg. `#[cfg(test)]`
+    Flag(SmolStr),
+    /// eg. `#[cfg(target_os = "linux")]`
+    ///
+    /// Note that a key can have multiple values that are all considered "active" at the same time.
+    /// For example, `#[cfg(target_feature = "sse")]` and `#[cfg(target_feature = "sse2")]`.
+    KeyValue { key: SmolStr, value: SmolStr },
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum CfgExpr {
     Invalid,
-    Atom(SmolStr),
-    KeyValue { key: SmolStr, value: SmolStr },
+    Atom(CfgAtom),
     All(Vec<CfgExpr>),
     Any(Vec<CfgExpr>),
     Not(Box<CfgExpr>),
 }
 
+impl From<CfgAtom> for CfgExpr {
+    fn from(atom: CfgAtom) -> Self {
+        CfgExpr::Atom(atom)
+    }
+}
+
 impl CfgExpr {
     pub fn parse(tt: &tt::Subtree) -> CfgExpr {
         next_cfg_expr(&mut tt.token_trees.iter()).unwrap_or(CfgExpr::Invalid)
     }
     /// Fold the cfg by querying all basic `Atom` and `KeyValue` predicates.
-    pub fn fold(&self, query: &dyn Fn(&SmolStr, Option<&SmolStr>) -> bool) -> Option<bool> {
+    pub fn fold(&self, query: &dyn Fn(&CfgAtom) -> bool) -> Option<bool> {
         match self {
             CfgExpr::Invalid => None,
-            CfgExpr::Atom(name) => Some(query(name, None)),
-            CfgExpr::KeyValue { key, value } => Some(query(key, Some(value))),
+            CfgExpr::Atom(atom) => Some(query(atom)),
             CfgExpr::All(preds) => {
                 preds.iter().try_fold(true, |s, pred| Some(s && pred.fold(query)?))
             }
@@ -54,7 +70,7 @@ fn next_cfg_expr(it: &mut SliceIter<tt::TokenTree>) -> Option<CfgExpr> {
                     // FIXME: escape? raw string?
                     let value =
                         SmolStr::new(literal.text.trim_start_matches('"').trim_end_matches('"'));
-                    CfgExpr::KeyValue { key: name, value }
+                    CfgAtom::KeyValue { key: name, value }.into()
                 }
                 _ => return Some(CfgExpr::Invalid),
             }
@@ -70,7 +86,7 @@ fn next_cfg_expr(it: &mut SliceIter<tt::TokenTree>) -> Option<CfgExpr> {
                 _ => CfgExpr::Invalid,
             }
         }
-        _ => CfgExpr::Atom(name),
+        _ => CfgAtom::Flag(name).into(),
     };
 
     // Eat comma separator
@@ -101,22 +117,22 @@ mod tests {
 
     #[test]
     fn test_cfg_expr_parser() {
-        assert_parse_result("#![cfg(foo)]", CfgExpr::Atom("foo".into()));
-        assert_parse_result("#![cfg(foo,)]", CfgExpr::Atom("foo".into()));
+        assert_parse_result("#![cfg(foo)]", CfgAtom::Flag("foo".into()).into());
+        assert_parse_result("#![cfg(foo,)]", CfgAtom::Flag("foo".into()).into());
         assert_parse_result(
             "#![cfg(not(foo))]",
-            CfgExpr::Not(Box::new(CfgExpr::Atom("foo".into()))),
+            CfgExpr::Not(Box::new(CfgAtom::Flag("foo".into()).into())),
         );
         assert_parse_result("#![cfg(foo(bar))]", CfgExpr::Invalid);
 
         // Only take the first
-        assert_parse_result(r#"#![cfg(foo, bar = "baz")]"#, CfgExpr::Atom("foo".into()));
+        assert_parse_result(r#"#![cfg(foo, bar = "baz")]"#, CfgAtom::Flag("foo".into()).into());
 
         assert_parse_result(
             r#"#![cfg(all(foo, bar = "baz"))]"#,
             CfgExpr::All(vec![
-                CfgExpr::Atom("foo".into()),
-                CfgExpr::KeyValue { key: "bar".into(), value: "baz".into() },
+                CfgAtom::Flag("foo".into()).into(),
+                CfgAtom::KeyValue { key: "bar".into(), value: "baz".into() }.into(),
             ]),
         );
 
@@ -126,7 +142,7 @@ mod tests {
                 CfgExpr::Not(Box::new(CfgExpr::Invalid)),
                 CfgExpr::All(vec![]),
                 CfgExpr::Invalid,
-                CfgExpr::KeyValue { key: "bar".into(), value: "baz".into() },
+                CfgAtom::KeyValue { key: "bar".into(), value: "baz".into() }.into(),
             ]),
         );
     }
diff --git a/crates/cfg/src/lib.rs b/crates/cfg/src/lib.rs
index a9d50e698..35f540ac3 100644
--- a/crates/cfg/src/lib.rs
+++ b/crates/cfg/src/lib.rs
@@ -5,7 +5,7 @@ mod cfg_expr;
 use rustc_hash::FxHashSet;
 use tt::SmolStr;
 
-pub use cfg_expr::CfgExpr;
+pub use cfg_expr::{CfgAtom, 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
@@ -19,33 +19,25 @@ pub use cfg_expr::CfgExpr;
 /// 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)>,
+    enabled: FxHashSet<CfgAtom>,
 }
 
 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())),
-        })
+        cfg.fold(&|atom| self.enabled.contains(atom))
     }
 
     pub fn insert_atom(&mut self, key: SmolStr) {
-        self.atoms.insert(key);
+        self.enabled.insert(CfgAtom::Flag(key));
     }
 
     pub fn insert_key_value(&mut self, key: SmolStr, value: SmolStr) {
-        self.key_values.insert((key, value));
+        self.enabled.insert(CfgAtom::KeyValue { key, value });
     }
 
     pub fn append(&mut self, other: &CfgOptions) {
-        for atom in &other.atoms {
-            self.atoms.insert(atom.clone());
-        }
-
-        for (key, value) in &other.key_values {
-            self.key_values.insert((key.clone(), value.clone()));
+        for atom in &other.enabled {
+            self.enabled.insert(atom.clone());
         }
     }
 }