1 files changed, 105 insertions, 0 deletions
diff --git a/js/xpconnect/tests/unit/test_tearoffs.js b/js/xpconnect/tests/unit/test_tearoffs.js
new file mode 100644
index 0000000000..cdf1d1025b
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_tearoffs.js
@@ -0,0 +1,105 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() {
+
+  // Load the component manifest containing our test interface implementations.
+  Components.manager.autoRegister(do_get_file('../components/js/xpctest.manifest'));
+
+  // Shortcut the interfaces we're using.
+  var ifs = {
+    a: Ci['nsIXPCTestInterfaceA'],
+    b: Ci['nsIXPCTestInterfaceB'],
+    c: Ci['nsIXPCTestInterfaceC']
+  };
+
+  // Shortcut the class we're instantiating. This implements all three interfaces.
+  var cls = Cc["@mozilla.org/js/xpc/test/js/TestInterfaceAll;1"];
+
+  // Run through the logic a few times.
+  for (i = 0; i < 2; ++i)
+    play_with_tearoffs(ifs, cls);
+}
+
+function play_with_tearoffs(ifs, cls) {
+
+  // Allocate a bunch of objects, QI-ed to B.
+  var instances = [];
+  for (var i = 0; i < 300; ++i)
+    instances.push(cls.createInstance(ifs.b));
+
+  // Nothing to collect.
+  gc();
+
+  // QI them to A.
+  instances.forEach(function(v, i, a) { v.QueryInterface(ifs.a); });
+
+  // QI them to C.
+  instances.forEach(function(v, i, a) { v.QueryInterface(ifs.c); });
+
+  // Check
+  Assert.ok('name' in instances[10], 'Have the prop from A/B');
+  Assert.ok('someInteger' in instances[10], 'Have the prop from C');
+
+  // Grab tearoff reflections for a and b.
+  var aTearOffs = instances.map(function(v, i, a) { return v.nsIXPCTestInterfaceA; } );
+  var bTearOffs = instances.map(function(v, i, a) { return v.nsIXPCTestInterfaceB; } );
+
+  // Check
+  Assert.ok('name' in aTearOffs[1], 'Have the prop from A');
+  Assert.ok(!('someInteger' in aTearOffs[1]), 'Dont have the prop from C');
+
+  // Nothing to collect.
+  gc();
+
+  // Null out every even instance pointer.
+  for (var i = 0; i < instances.length; ++i)
+    if (i % 2 == 0)
+        instances[i] = null;
+
+  // Nothing to collect, since we still have the A and B tearoff reflections.
+  gc();
+
+  // Null out A tearoff reflections that are a multiple of 3.
+  for (var i = 0; i < aTearOffs.length; ++i)
+    if (i % 3 == 0)
+        aTearOffs[i] = null;
+
+  // Nothing to collect, since we still have the B tearoff reflections.
+  gc();
+
+  // Null out B tearoff reflections that are a multiple of 5.
+  for (var i = 0; i < bTearOffs.length; ++i)
+    if (i % 5 == 0)
+        bTearOffs[i] = null;
+
+  // This should collect every 30th object (indices that are multiples of 2, 3, and 5).
+  gc();
+
+  // Kill the b tearoffs entirely.
+  bTearOffs = 0;
+
+  // Collect more.
+  gc();
+
+  // Get C tearoffs.
+  var cTearOffs = instances.map(function(v, i, a) { return v ? v.nsIXPCTestInterfaceC : null; } );
+
+  // Check.
+  Assert.ok(!('name' in cTearOffs[1]), 'Dont have the prop from A');
+  Assert.ok('someInteger' in cTearOffs[1], 'have the prop from C');
+
+  // Null out the a tearoffs.
+  aTearOffs = null;
+
+  // Collect all even indices.
+  gc();
+
+  // Collect all indices.
+  instances = null;
+  gc();
+
+  // Give ourselves a pat on the back. :-)
+  Assert.ok(true, "Got all the way through without crashing!");
+}