Bug 1866882 - Part 2: Add tests for `nsIWindowsMutex`. r=nalexander,mhughes

Differential Revision: https://phabricator.services.mozilla.com/D195190

toolkit/mozapps/defaultagent/moz.build

@@ -86,6 +86,8 @@ XPCOM_MANIFESTS += [
     "components.conf",
 ]
 
+XPCSHELL_TESTS_MANIFESTS += ["tests/xpcshell/xpcshell.toml"]
+
 # If defines are added to this list that are required by the Cache,
 # SetDefaultBrowser, or their dependencies (Registry, EventLog, common),
 # tests/gtest/moz.build will need to be updated as well.

toolkit/mozapps/defaultagent/tests/xpcshell/test_windows_mutex.js

+/* Any copyright is dedicated to the Public Domain.
+http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Multiple instances of a named mutex on Windows can lock on the same thread, so
+// we have to run each test across at least two distinct threads. Running on a
+// separate process achieves the same.
+do_load_child_test_harness();
+
+let parentFactory = Cc["@mozilla.org/windows-mutex-factory;1"].createInstance(
+  Ci.nsIWindowsMutexFactory
+);
+
+function promiseCommand(aCommand) {
+  // Exceptions don't propogate to the process that called `sendCommand` nor
+  // tigger a test failure, so wrap the command to ensure we fail appropriately.
+  let wrappedCommand = `try {${aCommand}} catch(e) {Assert.ok(false, "Error running command received in child process. Note the passed in function must be self-contained. Error: \${e.toString()}");}`;
+  return new Promise(resolve => sendCommand(wrappedCommand, resolve));
+}
+
+// This is passed as a string to a child process, thus must be self-contained.
+function assertLockOkOnChild(aName, aTestString) {
+  if (Services.appinfo.processType != Ci.nsIXULRuntime.PROCESS_TYPE_CONTENT) {
+    Assert.ok(false, `${assertLockOkOnChild.name} run on child process.`);
+  }
+
+  let childFactory = Cc["@mozilla.org/windows-mutex-factory;1"].createInstance(
+    Ci.nsIWindowsMutexFactory
+  );
+
+  let lockingMutex = childFactory.createMutex(aName);
+
+  info(`Locking mutex for subtest "${aTestString}"`);
+  lockingMutex.tryLock();
+  try {
+    Assert.ok(lockingMutex.isLocked(), aTestString);
+  } finally {
+    lockingMutex.unlock();
+  }
+}
+
+// This is passed as a string to a child process, thus must be self-contained.
+function assertLockThrowsOnChild(aName, aTestString) {
+  if (Services.appinfo.processType != Ci.nsIXULRuntime.PROCESS_TYPE_CONTENT) {
+    Assert.ok(false, `${assertLockThrowsOnChild.name} run on child process.`);
+  }
+
+  let childFactory = Cc["@mozilla.org/windows-mutex-factory;1"].createInstance(
+    Ci.nsIWindowsMutexFactory
+  );
+
+  let blockedMutex = childFactory.createMutex(aName);
+
+  info(`Locking mutex for subtest "${aTestString}"`);
+  Assert.throws(blockedMutex.tryLock, /NS_ERROR_NOT_AVAILABLE/, aTestString);
+  Assert.ok(!blockedMutex.isLocked(), "Not locked after error.");
+}
+
+add_task(async function test_lock_blocks() {
+  const kTestMutexName = Services.uuid.generateUUID().toString();
+  let lockingMutex = parentFactory.createMutex(kTestMutexName);
+
+  Assert.ok(!lockingMutex.isLocked(), "Reported unlocked before locking.");
+
+  info(`Locking mutex named "${kTestMutexName}"`);
+  lockingMutex.tryLock();
+  try {
+    Assert.ok(lockingMutex.isLocked(), "Reported locked after locking.");
+
+    await promiseCommand(
+      `(${assertLockThrowsOnChild.toString()})("${kTestMutexName}", "Concurrent attempts to lock identically named mutex throws.");`
+    );
+  } finally {
+    lockingMutex.unlock();
+  }
+});
+
+add_task(async function test_unlock_unblocks() {
+  const kTestMutexName = Services.uuid.generateUUID().toString();
+  let lockingMutex = parentFactory.createMutex(kTestMutexName);
+
+  info(`Locking mutex named "${kTestMutexName}"`);
+  lockingMutex.tryLock();
+  lockingMutex.unlock();
+
+  Assert.ok(!lockingMutex.isLocked(), "Reported unlocked after unlocking.");
+
+  await promiseCommand(
+    `(${assertLockOkOnChild.toString()})("${kTestMutexName}", "Locked previously unlocked mutex.");`
+  );
+});
+
+add_task(async function test_names_dont_conflict() {
+  const kTestMutexName = Services.uuid.generateUUID().toString();
+  let mutex1 = parentFactory.createMutex(kTestMutexName);
+
+  info(`Locking mutex named "${kTestMutexName}"`);
+  mutex1.tryLock();
+  try {
+    await promiseCommand(
+      `(${assertLockOkOnChild.toString()})(Services.uuid.generateUUID().toString(), "Differently named mutexes don't conflict");`
+    );
+  } finally {
+    mutex1.unlock();
+  }
+});
+
+add_task(async function test_relock_when_locked() {
+  const kTestMutexName = Services.uuid.generateUUID().toString();
+  let mutex = parentFactory.createMutex(kTestMutexName);
+
+  mutex.tryLock();
+  try {
+    Assert.ok(() => mutex.tryLock(), "Relocking locked mutex succeeds.");
+    Assert.ok(
+      mutex.isLocked(),
+      "Reported locked after relocking locked mutex."
+    );
+  } finally {
+    mutex.unlock();
+  }
+});
+
+add_task(async function test_unlock_without_lock() {
+  const kTestMutexName = Services.uuid.generateUUID().toString();
+  let mutex = parentFactory.createMutex(kTestMutexName);
+
+  mutex.unlock();
+  Assert.ok(
+    !mutex.isLocked(),
+    "Reported unlocked after unnecessarily unlocking mutex."
+  );
+
+  mutex.tryLock();
+  try {
+    Assert.ok(
+      mutex.isLocked(),
+      "Reported locked after locking unnecessarily unlocked mutex."
+    );
+  } finally {
+    mutex.unlock();
+  }
+});

toolkit/mozapps/defaultagent/tests/xpcshell/xpcshell.toml

+[DEFAULT]
+run-if = ["os == 'win'"]
+
+["test_windows_mutex.js"]