Issue 6815 - Avoid multiple copies of domain maps

test/filterClasses.js

Index: test/filterClasses.js
===================================================================
--- a/test/filterClasses.js
+++ b/test/filterClasses.js
@@ -538,17 +538,16 @@
              "f$o$o$csp=f o o");
   test.equal(Filter.normalize("/foo$/$ csp = script-src  http://example.com/?$1=1&$2=2&$3=3"),
              "/foo$/$csp=script-src http://example.com/?$1=1&$2=2&$3=3");
   test.equal(Filter.normalize("||content.server.com/files/*.php$rewrite= $1"),
              "||content.server.com/files/*.php$rewrite=$1");
   test.done();
 };
 
-
 exports.testFilterRewriteOption = function(test)
 {
   let text = "/(content\\.server\\/file\\/.*\\.txt)\\?.*$/$rewrite=$1";
 
   let filter = Filter.fromText(text);
 
   test.equal(filter.rewrite, "$1");
   // no rewrite occured: didn't match.
@@ -598,8 +597,24 @@
   test.equal(filterStrip.rewrite, "");
   test.equal(
     filterStrip.rewriteUrl("http://example.com/?tag"),
     "http://example.com/?"
   );
 
   test.done();
 };
+
+exports.testDomainMapDeduplication = function(test)
+{
+  let filter1 = Filter.fromText("example.com##.foo");
+  let filter2 = Filter.fromText("example.com##.bar");
+
+  // This compares the references to make sure that both refer to the same
+  // object (#6815).
+  test.equal(filter1.domains, filter2.domains);
+
+  let filter3 = Filter.fromText("www.example.com##.bar");
+
+  test.notEqual(filter2.domains, filter3.domains);
+
+  test.done();
+};