# HG changeset patch
# User Jaroslav Tulach <jaroslav.tulach@apidesign.org>
# Date 1355689166 -3600
# Node ID b8fd5ab83a2039a1cddbb5a6344187715f91e634
# Parent  b5dd05670bef61a9a18402693b9ebdd2c980891e
Giving objects some basic and stable hashCode

diff -r b5dd05670bef -r b8fd5ab83a20 emul/src/main/java/java/lang/Object.java
--- a/emul/src/main/java/java/lang/Object.java	Sun Dec 16 20:48:21 2012 +0100
+++ b/emul/src/main/java/java/lang/Object.java	Sun Dec 16 21:19:26 2012 +0100
@@ -104,6 +104,11 @@
      * @see     java.lang.Object#equals(java.lang.Object)
      * @see     java.lang.System#identityHashCode
      */
+    @JavaScriptBody(args = "self", body = 
+        "if (self.$hashCode) return self.$hashCode;\n"
+        + "var h = Math.random() * Math.pow(2, 32);\n"
+        + "return self.$hashCode = h & h;"
+    )
     public native int hashCode();
 
     /**
diff -r b5dd05670bef -r b8fd5ab83a20 vm/src/test/java/org/apidesign/vm4brwsr/tck/CompareHashTest.java
--- a/vm/src/test/java/org/apidesign/vm4brwsr/tck/CompareHashTest.java	Sun Dec 16 20:48:21 2012 +0100
+++ b/vm/src/test/java/org/apidesign/vm4brwsr/tck/CompareHashTest.java	Sun Dec 16 21:19:26 2012 +0100
@@ -30,6 +30,11 @@
         return "Ahoj".hashCode();
     }
     
+    @Compare public int hashRemainsYieldsZero() {
+        Object o = new Object();
+        return o.hashCode() - o.hashCode();
+    }
+    
     @Factory
     public static Object[] create() {
         return CompareVMs.create(CompareHashTest.class);