libsyntax: Remove `@str` from the interner

4 files changed, 112 insertions, 56 deletions

diff --git a/src/libsyntax/ast_map.rs b/src/libsyntax/ast_map.rs
index bb66d620d29..89209ab2104 100644
--- a/src/libsyntax/ast_map.rs
+++ b/src/libsyntax/ast_map.rs
@@ -62,9 +62,10 @@ pub fn path_to_str_with_sep(p: &[PathElem], sep: &str, itr: @IdentInterner)
 
 pub fn path_ident_to_str(p: &Path, i: Ident, itr: @IdentInterner) -> ~str {
     if p.is_empty() {
-        itr.get(i.name).to_owned()
+        itr.get(i.name).into_owned()
     } else {
-        format!("{}::{}", path_to_str(*p, itr), itr.get(i.name))
+        let string = itr.get(i.name);
+        format!("{}::{}", path_to_str(*p, itr), string.as_slice())
     }
 }
 
@@ -75,7 +76,7 @@ pub fn path_to_str(p: &[PathElem], itr: @IdentInterner) -> ~str {
 pub fn path_elem_to_str(pe: PathElem, itr: @IdentInterner) -> ~str {
     match pe {
         PathMod(s) | PathName(s) | PathPrettyName(s, _) => {
-            itr.get(s.name).to_owned()
+            itr.get(s.name).into_owned()
         }
     }
 }
@@ -105,7 +106,11 @@ fn pretty_ty(ty: &Ty, itr: @IdentInterner, out: &mut ~str) {
         // need custom handling.
         TyNil => { out.push_str("$NIL$"); return }
         TyPath(ref path, _, _) => {
-            out.push_str(itr.get(path.segments.last().unwrap().identifier.name));
+            out.push_str(itr.get(path.segments
+                                     .last()
+                                     .unwrap()
+                                     .identifier
+                                     .name).as_slice());
             return
         }
         TyTup(ref tys) => {
@@ -138,7 +143,8 @@ pub fn impl_pretty_name(trait_ref: &Option<TraitRef>, ty: &Ty) -> PathElem {
     match *trait_ref {
         None => pretty = ~"",
         Some(ref trait_ref) => {
-            pretty = itr.get(trait_ref.path.segments.last().unwrap().identifier.name).to_owned();
+            pretty = itr.get(trait_ref.path.segments.last().unwrap().identifier.name)
+                        .into_owned();
             pretty.push_char('$');
         }
     };
@@ -489,17 +495,21 @@ pub fn node_id_to_str(map: Map, id: NodeId, itr: @IdentInterner) -> ~str {
              path_ident_to_str(path, item.ident, itr), abi, id)
       }
       Some(NodeMethod(m, _, path)) => {
+        let name = itr.get(m.ident.name);
         format!("method {} in {} (id={})",
-             itr.get(m.ident.name), path_to_str(*path, itr), id)
+             name.as_slice(), path_to_str(*path, itr), id)
       }
       Some(NodeTraitMethod(ref tm, _, path)) => {
         let m = ast_util::trait_method_to_ty_method(&**tm);
+        let name = itr.get(m.ident.name);
         format!("method {} in {} (id={})",
-             itr.get(m.ident.name), path_to_str(*path, itr), id)
+             name.as_slice(), path_to_str(*path, itr), id)
       }
       Some(NodeVariant(ref variant, _, path)) => {
+        let name = itr.get(variant.node.name.name);
         format!("variant {} in {} (id={})",
-             itr.get(variant.node.name.name), path_to_str(*path, itr), id)
+             name.as_slice(),
+             path_to_str(*path, itr), id)
       }
       Some(NodeExpr(expr)) => {
         format!("expr {} (id={})", pprust::expr_to_str(expr, itr), id)
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 86913711801..dc16f32b872 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -3979,8 +3979,9 @@ impl Parser {
                 fields.push(self.parse_struct_decl_field());
             }
             if fields.len() == 0 {
+                let string = get_ident_interner().get(class_name.name);
                 self.fatal(format!("Unit-like struct definition should be written as `struct {};`",
-                                get_ident_interner().get(class_name.name)));
+                                   string.as_slice()));
             }
             self.bump();
         } else if self.token == token::LPAREN {
diff --git a/src/libsyntax/parse/token.rs b/src/libsyntax/parse/token.rs
index 806c84c5553..eb2fa151f51 100644
--- a/src/libsyntax/parse/token.rs
+++ b/src/libsyntax/parse/token.rs
@@ -12,7 +12,7 @@ use ast;
 use ast::{P, Name, Mrk};
 use ast_util;
 use parse::token;
-use util::interner::StrInterner;
+use util::interner::{RcStr, StrInterner};
 use util::interner;
 
 use extra::serialize::{Decodable, Decoder, Encodable, Encoder};
@@ -214,8 +214,11 @@ pub fn to_str(input: @IdentInterner, t: &Token) -> ~str {
       }
 
       /* Name components */
-      IDENT(s, _) => input.get(s.name).to_owned(),
-      LIFETIME(s) => format!("'{}", input.get(s.name)),
+      IDENT(s, _) => input.get(s.name).into_owned(),
+      LIFETIME(s) => {
+          let name = input.get(s.name);
+          format!("'{}", name.as_slice())
+      }
       UNDERSCORE => ~"_",
 
       /* Other */
@@ -549,7 +552,7 @@ pub fn get_ident_interner() -> @IdentInterner {
 #[no_send]
 #[deriving(Clone, Eq, IterBytes, Ord, TotalEq, TotalOrd)]
 pub struct InternedString {
-    priv string: @str,
+    priv string: RcStr,
 }
 
 #[unsafe_destructor]
@@ -563,13 +566,12 @@ impl InternedString {
     #[inline]
     pub fn new(string: &'static str) -> InternedString {
         InternedString {
-            string: string.to_managed(),
+            string: RcStr::new(string),
         }
     }
 
-    // NB: Do not make this public. We are trying to remove `@str`.
     #[inline]
-    fn new_from_at_str(string: @str) -> InternedString {
+    fn new_from_rc_str(string: RcStr) -> InternedString {
         InternedString {
             string: string,
         }
@@ -594,7 +596,7 @@ impl BytesContainer for InternedString {
 
 impl fmt::Default for InternedString {
     fn fmt(obj: &InternedString, f: &mut fmt::Formatter) {
-        write!(f.buf, "{}", obj.string);
+        write!(f.buf, "{}", obj.string.as_slice());
     }
 }
 
@@ -613,7 +615,7 @@ impl<D:Decoder> Decodable<D> for InternedString {
 
 impl<E:Encoder> Encodable<E> for InternedString {
     fn encode(&self, e: &mut E) {
-        e.emit_str(self.string)
+        e.emit_str(self.string.as_slice())
     }
 }
 
@@ -622,7 +624,7 @@ impl<E:Encoder> Encodable<E> for InternedString {
 #[inline]
 pub fn get_ident(idx: Name) -> InternedString {
     let interner = get_ident_interner();
-    InternedString::new_from_at_str(interner.get(idx))
+    InternedString::new_from_rc_str(interner.get(idx))
 }
 
 /// Interns and returns the string contents of an identifier, using the
diff --git a/src/libsyntax/util/interner.rs b/src/libsyntax/util/interner.rs
index c0fe19ede01..e20efda9c6e 100644
--- a/src/libsyntax/util/interner.rs
+++ b/src/libsyntax/util/interner.rs
@@ -18,6 +18,7 @@ use std::cast;
 use std::cell::RefCell;
 use std::cmp::Equiv;
 use std::hashmap::HashMap;
+use std::rc::Rc;
 
 pub struct Interner<T> {
     priv map: @RefCell<HashMap<T, Name>>,
@@ -83,11 +84,49 @@ impl<T:Eq + IterBytes + Hash + Freeze + Clone + 'static> Interner<T> {
     }
 }
 
+#[deriving(Clone, Eq, IterBytes, Ord)]
+pub struct RcStr {
+    priv string: Rc<~str>,
+}
+
+impl TotalEq for RcStr {
+    fn equals(&self, other: &RcStr) -> bool {
+        self.as_slice().equals(&other.as_slice())
+    }
+}
+
+impl TotalOrd for RcStr {
+    fn cmp(&self, other: &RcStr) -> Ordering {
+        self.as_slice().cmp(&other.as_slice())
+    }
+}
+
+impl Str for RcStr {
+    #[inline]
+    fn as_slice<'a>(&'a self) -> &'a str {
+        let s: &'a str = *self.string.borrow();
+        s
+    }
+
+    #[inline]
+    fn into_owned(self) -> ~str {
+        self.string.borrow().to_owned()
+    }
+}
+
+impl RcStr {
+    pub fn new(string: &str) -> RcStr {
+        RcStr {
+            string: Rc::new(string.to_owned()),
+        }
+    }
+}
+
 // A StrInterner differs from Interner<String> in that it accepts
 // references rather than @ ones, resulting in less allocation.
 pub struct StrInterner {
-    priv map: @RefCell<HashMap<@str, Name>>,
-    priv vect: @RefCell<~[@str]>,
+    priv map: @RefCell<HashMap<RcStr, Name>>,
+    priv vect: @RefCell<~[RcStr]>,
 }
 
 // when traits can extend traits, we should extend index<Name,T> to get []
@@ -113,8 +152,8 @@ impl StrInterner {
         }
 
         let new_idx = self.len() as Name;
-        let val = val.to_managed();
-        map.get().insert(val, new_idx);
+        let val = RcStr::new(val);
+        map.get().insert(val.clone(), new_idx);
         let mut vect = self.vect.borrow_mut();
         vect.get().push(val);
         new_idx
@@ -124,7 +163,7 @@ impl StrInterner {
         let new_idx = self.len() as Name;
         // leave out of .map to avoid colliding
         let mut vect = self.vect.borrow_mut();
-        vect.get().push(val.to_managed());
+        vect.get().push(RcStr::new(val));
         new_idx
     }
 
@@ -142,21 +181,21 @@ impl StrInterner {
         let new_idx = self.len() as Name;
         // leave out of map to avoid colliding
         let mut vect = self.vect.borrow_mut();
-        let existing = vect.get()[idx];
+        let existing = vect.get()[idx].clone();
         vect.get().push(existing);
         new_idx
     }
 
-    pub fn get(&self, idx: Name) -> @str {
+    pub fn get(&self, idx: Name) -> RcStr {
         let vect = self.vect.borrow();
-        vect.get()[idx]
+        vect.get()[idx].clone()
     }
 
     /// Returns this string with lifetime tied to the interner. Since
     /// strings may never be removed from the interner, this is safe.
     pub fn get_ref<'a>(&'a self, idx: Name) -> &'a str {
         let vect = self.vect.borrow();
-        let s: &str = vect.get()[idx];
+        let s: &str = vect.get()[idx].as_slice();
         unsafe {
             cast::transmute(s)
         }
@@ -167,7 +206,7 @@ impl StrInterner {
         vect.get().len()
     }
 
-    pub fn find_equiv<Q:Hash + IterBytes + Equiv<@str>>(&self, val: &Q)
+    pub fn find_equiv<Q:Hash + IterBytes + Equiv<RcStr>>(&self, val: &Q)
                                                          -> Option<Name> {
         let map = self.map.borrow();
         match map.get().find_equiv(val) {
@@ -183,42 +222,46 @@ mod tests {
     #[test]
     #[should_fail]
     fn i1 () {
-        let i : Interner<@str> = Interner::new();
+        let i : Interner<RcStr> = Interner::new();
         i.get(13);
     }
 
     #[test]
     fn interner_tests () {
-        let i : Interner<@str> = Interner::new();
+        let i : Interner<RcStr> = Interner::new();
         // first one is zero:
-        assert_eq!(i.intern(@"dog"), 0);
+        assert_eq!(i.intern(RcStr::new("dog")), 0);
         // re-use gets the same entry:
-        assert_eq!(i.intern(@"dog"), 0);
+        assert_eq!(i.intern(RcStr::new("dog")), 0);
         // different string gets a different #:
-        assert_eq!(i.intern(@"cat"), 1);
-        assert_eq!(i.intern(@"cat"), 1);
+        assert_eq!(i.intern(RcStr::new("cat")), 1);
+        assert_eq!(i.intern(RcStr::new("cat")), 1);
         // dog is still at zero
-        assert_eq!(i.intern(@"dog"), 0);
+        assert_eq!(i.intern(RcStr::new("dog")), 0);
         // gensym gets 3
-        assert_eq!(i.gensym(@"zebra" ), 2);
+        assert_eq!(i.gensym(RcStr::new("zebra") ), 2);
         // gensym of same string gets new number :
-        assert_eq!(i.gensym (@"zebra" ), 3);
+        assert_eq!(i.gensym (RcStr::new("zebra") ), 3);
         // gensym of *existing* string gets new number:
-        assert_eq!(i.gensym(@"dog"), 4);
-        assert_eq!(i.get(0), @"dog");
-        assert_eq!(i.get(1), @"cat");
-        assert_eq!(i.get(2), @"zebra");
-        assert_eq!(i.get(3), @"zebra");
-        assert_eq!(i.get(4), @"dog");
+        assert_eq!(i.gensym(RcStr::new("dog")), 4);
+        assert_eq!(i.get(0), RcStr::new("dog"));
+        assert_eq!(i.get(1), RcStr::new("cat"));
+        assert_eq!(i.get(2), RcStr::new("zebra"));
+        assert_eq!(i.get(3), RcStr::new("zebra"));
+        assert_eq!(i.get(4), RcStr::new("dog"));
     }
 
     #[test]
     fn i3 () {
-        let i : Interner<@str> = Interner::prefill([@"Alan",@"Bob",@"Carol"]);
-        assert_eq!(i.get(0), @"Alan");
-        assert_eq!(i.get(1), @"Bob");
-        assert_eq!(i.get(2), @"Carol");
-        assert_eq!(i.intern(@"Bob"), 1);
+        let i : Interner<@~str> = Interner::prefill([
+            RcStr::new("Alan"),
+            RcStr::new("Bob"),
+            RcStr::new("Carol")
+        ]);
+        assert_eq!(i.get(0), RcStr::new("Alan"));
+        assert_eq!(i.get(1), RcStr::new("Bob"));
+        assert_eq!(i.get(2), RcStr::new("Carol"));
+        assert_eq!(i.intern(RcStr::new("Bob")), 1);
     }
 
     #[test]
@@ -241,13 +284,13 @@ mod tests {
         assert_eq!(i.gensym("dog"), 4);
         // gensym tests again with gensym_copy:
         assert_eq!(i.gensym_copy(2), 5);
-        assert_eq!(i.get(5), @"zebra");
+        assert_eq!(i.get(5), RcStr::new("zebra"));
         assert_eq!(i.gensym_copy(2), 6);
-        assert_eq!(i.get(6), @"zebra");
-        assert_eq!(i.get(0), @"dog");
-        assert_eq!(i.get(1), @"cat");
-        assert_eq!(i.get(2), @"zebra");
-        assert_eq!(i.get(3), @"zebra");
-        assert_eq!(i.get(4), @"dog");
+        assert_eq!(i.get(6), RcStr::new("zebra"));
+        assert_eq!(i.get(0), RcStr::new("dog"));
+        assert_eq!(i.get(1), RcStr::new("cat"));
+        assert_eq!(i.get(2), RcStr::new("zebra"));
+        assert_eq!(i.get(3), RcStr::new("zebra"));
+        assert_eq!(i.get(4), RcStr::new("dog"));
     }
 }