WeakReference. Apply directly to the forehead.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5725 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/as/com/threerings/util/WeakReference.as

@@ -0,0 +1,36 @@
+//
+// $Id$
+
+package com.threerings.util {
+
+import flash.utils.Dictionary;
+
+/**
+ * A weak reference. At some point in the future the referent might not be available
+ * anymore.
+ */
+public class WeakReference
+{
+    /**
+     * No, you cannot store undefined here.
+     */
+    public function WeakReference (referant :Object)
+    {
+        _ref[referant] = true;
+    }
+
+    /**
+     * Return the referant, or undefined if it's been collected.
+     */
+    public function get () :*
+    {
+        for (var k :* in _ref) {
+            return k;
+        }
+        return undefined;
+    }
+
+    /** The only way to have a weak reference in actionscript. */
+    protected var _ref :Dictionary = new Dictionary(true);
+}
+}