test_tearoffs.js - mozsearch

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/* 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 TestInterfaceAll() {}

TestInterfaceAll.prototype = {

  QueryInterface: ChromeUtils.generateQI(["nsIXPCTestInterfaceA",

                                          "nsIXPCTestInterfaceB",

                                          "nsIXPCTestInterfaceC"]),

  /* nsIXPCTestInterfaceA / nsIXPCTestInterfaceB */

  name: "TestInterfaceAllDefaultName",

  /* nsIXPCTestInterfaceC */

  someInteger: 42

};

function newWrappedJS() {

  return xpcWrap(new TestInterfaceAll());

function run_test() {

  // Shortcut the interfaces we're using.

  var ifs = {

    a: Ci['nsIXPCTestInterfaceA'],

    b: Ci['nsIXPCTestInterfaceB'],

    c: Ci['nsIXPCTestInterfaceC']

};

  // Run through the logic a few times.

  for (let i = 0; i < 2; ++i)

    play_with_tearoffs(ifs);

function play_with_tearoffs(ifs) {

  // Allocate a bunch of objects, QI-ed to B.

  var instances = [];

  for (var i = 0; i < 300; ++i)

    instances.push(newWrappedJS().QueryInterface(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!");