libsyntax: Introduce an `InternedString` type to reduce `@str` in the

compiler and use it for attributes

1 files changed, 11 insertions, 0 deletions

diff --git a/src/libsyntax/util/interner.rs b/src/libsyntax/util/interner.rs
index fdc54f1f140..c0fe19ede01 100644
--- a/src/libsyntax/util/interner.rs
+++ b/src/libsyntax/util/interner.rs
@@ -14,6 +14,7 @@
 
 use ast::Name;
 
+use std::cast;
 use std::cell::RefCell;
 use std::cmp::Equiv;
 use std::hashmap::HashMap;
@@ -151,6 +152,16 @@ impl StrInterner {
         vect.get()[idx]
     }
 
+    /// 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];
+        unsafe {
+            cast::transmute(s)
+        }
+    }
+
     pub fn len(&self) -> uint {
         let vect = self.vect.borrow();
         vect.get().len()