Split libcore/arc.rs: arc -> std::arc; exclusive -> unsafe::exclusive

src/libstd/arc.rs

@@ -0,0 +1,83 @@
+/**
+ * Concurrency-enabled mechanisms for sharing mutable and/or immutable state
+ * between tasks.
+ */
+
+import unsafe::{shared_mutable_state, clone_shared_mutable_state,
+                get_shared_mutable_state, get_shared_immutable_state};
+
+export arc, clone, get;
+
+/****************************************************************************
+ * Immutable ARC
+ ****************************************************************************/
+
+/// An atomically reference counted wrapper for shared immutable state.
+struct arc<T: const send> { x: shared_mutable_state<T>; }
+
+/// Create an atomically reference counted wrapper.
+fn arc<T: const send>(+data: T) -> arc<T> {
+    arc { x: unsafe { shared_mutable_state(data) } }
+}
+
+/**
+ * Access the underlying data in an atomically reference counted
+ * wrapper.
+ */
+fn get<T: const send>(rc: &arc<T>) -> &T {
+    unsafe { get_shared_immutable_state(&rc.x) }
+}
+
+/**
+ * Duplicate an atomically reference counted wrapper.
+ *
+ * The resulting two `arc` objects will point to the same underlying data
+ * object. However, one of the `arc` objects can be sent to another task,
+ * allowing them to share the underlying data.
+ */
+fn clone<T: const send>(rc: &arc<T>) -> arc<T> {
+    arc { x: unsafe { clone_shared_mutable_state(&rc.x) } }
+}
+
+/****************************************************************************
+ * Mutex protected ARC (unsafe)
+ ****************************************************************************/
+
+/****************************************************************************
+ * R/W lock protected ARC
+ ****************************************************************************/
+
+/****************************************************************************
+ * Tests
+ ****************************************************************************/
+
+#[cfg(test)]
+mod tests {
+    import comm::*;
+
+    #[test]
+    fn manually_share_arc() {
+        let v = ~[1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+        let arc_v = arc::arc(v);
+
+        let p = port();
+        let c = chan(p);
+
+        do task::spawn() {
+            let p = port();
+            c.send(chan(p));
+
+            let arc_v = p.recv();
+
+            let v = *arc::get::<~[int]>(&arc_v);
+            assert v[3] == 4;
+        };
+
+        let c = p.recv();
+        c.send(arc::clone(&arc_v));
+
+        assert (*arc::get(&arc_v))[2] == 3;
+
+        log(info, arc_v);
+    }
+}