Introduce SchedulerSingleThreadTaskRunnerManager

base/task_scheduler/scheduler_single_thread_task_runner_manager_unittest.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/task_scheduler/scheduler_single_thread_task_runner_manager.h"
+
+#include "base/bind.h"
+#include "base/memory/ptr_util.h"
+#include "base/synchronization/lock.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/task_scheduler/delayed_task_manager.h"
+#include "base/task_scheduler/post_task.h"
+#include "base/task_scheduler/scheduler_worker_pool_params.h"
+#include "base/task_scheduler/task_tracker.h"
+#include "base/task_scheduler/task_traits.h"
+#include "base/test/test_timeouts.h"
+#include "base/threading/simple_thread.h"
+#include "base/threading/thread.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace internal {
+
+namespace {
+
+enum WorkerPoolType : size_t {
+  BACKGROUND_WORKER_POOL = 0,
+  FOREGROUND_WORKER_POOL,
+};
+
+static size_t GetThreadPoolIndexForTraits(const TaskTraits& traits) {
+  return traits.priority() == TaskPriority::BACKGROUND ? BACKGROUND_WORKER_POOL
+                                                       : FOREGROUND_WORKER_POOL;
+}
+
+std::vector<SchedulerWorkerPoolParams> GetParamsVector() {
+  using StandbyThreadPolicy = SchedulerWorkerPoolParams::StandbyThreadPolicy;
+
+  std::vector<SchedulerWorkerPoolParams> params_vector;
+
+  DCHECK_EQ(BACKGROUND_WORKER_POOL, params_vector.size());
+  params_vector.emplace_back("Background", ThreadPriority::BACKGROUND,
+                             StandbyThreadPolicy::LAZY, 1U, TimeDelta::Max());
+
+  DCHECK_EQ(FOREGROUND_WORKER_POOL, params_vector.size());
+  params_vector.emplace_back("Foreground", ThreadPriority::NORMAL,
+                             StandbyThreadPolicy::LAZY, 1U, TimeDelta::Max());
+
+  return params_vector;
+}
+
+class TaskSchedulerSingleThreadTaskRunnerManagerTest : public testing::Test {
+ public:
+  TaskSchedulerSingleThreadTaskRunnerManagerTest()
+      : service_thread_("TaskSchedulerServiceThread") {}
+
+  void SetUp() override {
+    service_thread_.Start();
+
+    delayed_task_manager_ =
+        MakeUnique<DelayedTaskManager>(service_thread_.task_runner());
+    single_thread_task_runner_manager_ =
+        MakeUnique<SchedulerSingleThreadTaskRunnerManager>(
+            GetParamsVector(), Bind(&GetThreadPoolIndexForTraits),
+            &task_tracker_, delayed_task_manager_.get());
+  }
+
+  void TearDown() override {
+    TearDownSingleThreadTaskRunnerManager();
+    delayed_task_manager_.reset();
+    service_thread_.Stop();
+  }
+
+ protected:
+  virtual void TearDownSingleThreadTaskRunnerManager() {
+    single_thread_task_runner_manager_->JoinForTesting();
+    single_thread_task_runner_manager_.reset();
+  }
+
+  std::unique_ptr<SchedulerSingleThreadTaskRunnerManager>
+      single_thread_task_runner_manager_;
+  TaskTracker task_tracker_;
+
+ private:
+  Thread service_thread_;
+  std::unique_ptr<DelayedTaskManager> delayed_task_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(TaskSchedulerSingleThreadTaskRunnerManagerTest);
+};
+
+void CaptureThreadRef(PlatformThreadRef* thread_ref) {
+  ASSERT_TRUE(thread_ref);
+  *thread_ref = PlatformThread::CurrentRef();
+}
+
+void CaptureThreadPriority(ThreadPriority* thread_priority) {
+  ASSERT_TRUE(thread_priority);
+  *thread_priority = PlatformThread::GetCurrentThreadPriority();
+}
+
+void ShouldNotRun() {
+  ADD_FAILURE() << "Ran a task that shouldn't run.";
+}
+
+}  // namespace
+
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerTest, DifferentThreadsUsed) {
+  scoped_refptr<SingleThreadTaskRunner> task_runner_1 =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits().WithShutdownBehavior(
+                  TaskShutdownBehavior::BLOCK_SHUTDOWN));
+  scoped_refptr<SingleThreadTaskRunner> task_runner_2 =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits().WithShutdownBehavior(
+                  TaskShutdownBehavior::BLOCK_SHUTDOWN));
+
+  PlatformThreadRef thread_ref_1;
+  task_runner_1->PostTask(FROM_HERE, Bind(&CaptureThreadRef, &thread_ref_1));
+  PlatformThreadRef thread_ref_2;
+  task_runner_2->PostTask(FROM_HERE, Bind(&CaptureThreadRef, &thread_ref_2));
+
+  task_tracker_.Shutdown();
+
+  ASSERT_FALSE(thread_ref_1.is_null());
+  ASSERT_FALSE(thread_ref_2.is_null());
+  EXPECT_NE(thread_ref_1, thread_ref_2);
+}
+
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerTest, PrioritySetCorrectly) {
+  // Why are events used here instead of the task tracker?
+  // Shutting down can cause priorities to get raised. This means we have to use
+  // events to determine when a task is run.
+  scoped_refptr<SingleThreadTaskRunner> task_runner_background =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits().WithPriority(TaskPriority::BACKGROUND));
+  scoped_refptr<SingleThreadTaskRunner> task_runner_user_visible =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits().WithPriority(TaskPriority::USER_VISIBLE));
+  scoped_refptr<SingleThreadTaskRunner> task_runner_user_blocking =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits()
+                  .WithPriority(TaskPriority::USER_BLOCKING)
+                  .WithShutdownBehavior(TaskShutdownBehavior::BLOCK_SHUTDOWN));
+
+  ThreadPriority thread_priority_background;
+  task_runner_background->PostTask(
+      FROM_HERE, Bind(&CaptureThreadPriority, &thread_priority_background));
+  WaitableEvent waitable_event_background(
+      WaitableEvent::ResetPolicy::MANUAL,
+      WaitableEvent::InitialState::NOT_SIGNALED);
+  task_runner_background->PostTask(
+      FROM_HERE,
+      Bind(&WaitableEvent::Signal, Unretained(&waitable_event_background)));
+
+  ThreadPriority thread_priority_user_visible;
+  task_runner_user_visible->PostTask(
+      FROM_HERE, Bind(&CaptureThreadPriority, &thread_priority_user_visible));
+  WaitableEvent waitable_event_user_visible(
+      WaitableEvent::ResetPolicy::MANUAL,
+      WaitableEvent::InitialState::NOT_SIGNALED);
+  task_runner_user_visible->PostTask(
+      FROM_HERE,
+      Bind(&WaitableEvent::Signal, Unretained(&waitable_event_user_visible)));
+
+  ThreadPriority thread_priority_user_blocking;
+  task_runner_user_blocking->PostTask(
+      FROM_HERE, Bind(&CaptureThreadPriority, &thread_priority_user_blocking));
+  WaitableEvent waitable_event_user_blocking(
+      WaitableEvent::ResetPolicy::MANUAL,
+      WaitableEvent::InitialState::NOT_SIGNALED);
+  task_runner_user_blocking->PostTask(
+      FROM_HERE,
+      Bind(&WaitableEvent::Signal, Unretained(&waitable_event_user_blocking)));
+
+  waitable_event_background.Wait();
+  waitable_event_user_visible.Wait();
+  waitable_event_user_blocking.Wait();
+
+  if (Lock::HandlesMultipleThreadPriorities())
+    EXPECT_EQ(ThreadPriority::BACKGROUND, thread_priority_background);
+  else
+    EXPECT_EQ(ThreadPriority::NORMAL, thread_priority_background);
+  EXPECT_EQ(ThreadPriority::NORMAL, thread_priority_user_visible);
+  EXPECT_EQ(ThreadPriority::NORMAL, thread_priority_user_blocking);
+}
+
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerTest, PostTaskAfterShutdown) {
+  auto task_runner = single_thread_task_runner_manager_
+                         ->CreateSingleThreadTaskRunnerWithTraits(TaskTraits());
+  task_tracker_.Shutdown();
+  EXPECT_FALSE(task_runner->PostTask(FROM_HERE, Bind(&ShouldNotRun)));
+}
+
+// Verify that a Task runs shortly after its delay expires.
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerTest, PostDelayedTask) {
+  TimeTicks start_time = TimeTicks::Now();
+
+  // Post a task with a short delay.
+  WaitableEvent task_ran(WaitableEvent::ResetPolicy::MANUAL,
+                         WaitableEvent::InitialState::NOT_SIGNALED);
+  auto task_runner = single_thread_task_runner_manager_
+                         ->CreateSingleThreadTaskRunnerWithTraits(TaskTraits());
+  EXPECT_TRUE(task_runner->PostDelayedTask(
+      FROM_HERE, Bind(&WaitableEvent::Signal, Unretained(&task_ran)),
+      TestTimeouts::tiny_timeout()));
+
+  // Wait until the task runs.
+  task_ran.Wait();
+
+  // Expect the task to run after its delay expires, but not more than 250 ms
+  // after that.
+  const TimeDelta actual_delay = TimeTicks::Now() - start_time;
+  EXPECT_GE(actual_delay, TestTimeouts::tiny_timeout());
+  EXPECT_LT(actual_delay,
+            TimeDelta::FromMilliseconds(250) + TestTimeouts::tiny_timeout());
+}
+
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerTest,
+       RunsTasksOnCurrentThread) {
+  scoped_refptr<SingleThreadTaskRunner> task_runner_1 =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits().WithShutdownBehavior(
+                  TaskShutdownBehavior::BLOCK_SHUTDOWN));
+  scoped_refptr<SingleThreadTaskRunner> task_runner_2 =
+      single_thread_task_runner_manager_
+          ->CreateSingleThreadTaskRunnerWithTraits(
+              TaskTraits().WithShutdownBehavior(
+                  TaskShutdownBehavior::BLOCK_SHUTDOWN));
+
+  EXPECT_FALSE(task_runner_1->RunsTasksOnCurrentThread());
+  EXPECT_FALSE(task_runner_2->RunsTasksOnCurrentThread());
+
+  task_runner_1->PostTask(
+      FROM_HERE, Bind(
+                     [](scoped_refptr<SingleThreadTaskRunner> task_runner_1,
+                        scoped_refptr<SingleThreadTaskRunner> task_runner_2) {
+                       EXPECT_TRUE(task_runner_1->RunsTasksOnCurrentThread());
+                       EXPECT_FALSE(task_runner_2->RunsTasksOnCurrentThread());
+                     },
+                     task_runner_1, task_runner_2));
+
+  task_runner_2->PostTask(
+      FROM_HERE, Bind(
+                     [](scoped_refptr<SingleThreadTaskRunner> task_runner_1,
+                        scoped_refptr<SingleThreadTaskRunner> task_runner_2) {
+                       EXPECT_FALSE(task_runner_1->RunsTasksOnCurrentThread());
+                       EXPECT_TRUE(task_runner_2->RunsTasksOnCurrentThread());
+                     },
+                     task_runner_1, task_runner_2));
+
+  task_tracker_.Shutdown();
+}
+
+namespace {
+
+class CallJoinFromDifferentThread : public SimpleThread {
+ public:
+  CallJoinFromDifferentThread(
+      SchedulerSingleThreadTaskRunnerManager* manager_to_join)
+      : SimpleThread("SchedulerSingleThreadTaskRunnerManagerJoinThread"),
+        manager_to_join_(manager_to_join),
+        run_started_event_(WaitableEvent::ResetPolicy::MANUAL,
+                           WaitableEvent::InitialState::NOT_SIGNALED) {}
+
+  ~CallJoinFromDifferentThread() override = default;
+
+  void Run() override {
+    run_started_event_.Signal();
+    manager_to_join_->JoinForTesting();
+  }
+
+  void WaitForRunToStart() { run_started_event_.Wait(); }
+
+ private:
+  SchedulerSingleThreadTaskRunnerManager* const manager_to_join_;
+  WaitableEvent run_started_event_;
+  DISALLOW_COPY_AND_ASSIGN(CallJoinFromDifferentThread);
+};
+
+class TaskSchedulerSingleThreadTaskRunnerManagerJoinTest
+    : public TaskSchedulerSingleThreadTaskRunnerManagerTest {
+ public:
+  TaskSchedulerSingleThreadTaskRunnerManagerJoinTest() = default;
+  ~TaskSchedulerSingleThreadTaskRunnerManagerJoinTest() override = default;
+
+ protected:
+  void TearDownSingleThreadTaskRunnerManager() override {
+    // The tests themselves are responsible for calling JoinForTesting().
+    single_thread_task_runner_manager_.reset();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TaskSchedulerSingleThreadTaskRunnerManagerJoinTest);
+};
+
+}  // namespace
+
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerJoinTest, ConcurrentJoin) {
+  WaitableEvent task_running(WaitableEvent::ResetPolicy::MANUAL,
+                             WaitableEvent::InitialState::NOT_SIGNALED);
+  WaitableEvent task_blocking(WaitableEvent::ResetPolicy::MANUAL,
+                              WaitableEvent::InitialState::NOT_SIGNALED);
+
+  {
+    auto task_runner = single_thread_task_runner_manager_
+                           ->CreateSingleThreadTaskRunnerWithTraits(
+                               TaskTraits().WithBaseSyncPrimitives());
+    EXPECT_TRUE(task_runner->PostTask(
+        FROM_HERE, Bind(&WaitableEvent::Signal, Unretained(&task_running))));
+    EXPECT_TRUE(task_runner->PostTask(
+        FROM_HERE, Bind(&WaitableEvent::Wait, Unretained(&task_blocking))));
+  }
+
+  task_running.Wait();
+  CallJoinFromDifferentThread join_from_different_thread(
+      single_thread_task_runner_manager_.get());
+  join_from_different_thread.Start();
+  join_from_different_thread.WaitForRunToStart();
+  task_blocking.Signal();
+  join_from_different_thread.Join();
+}
+
+TEST_F(TaskSchedulerSingleThreadTaskRunnerManagerJoinTest,
+       ConcurrentJoinExtraSkippedTask) {
+  WaitableEvent task_running(WaitableEvent::ResetPolicy::MANUAL,
+                             WaitableEvent::InitialState::NOT_SIGNALED);
+  WaitableEvent task_blocking(WaitableEvent::ResetPolicy::MANUAL,
+                              WaitableEvent::InitialState::NOT_SIGNALED);
+
+  {
+    auto task_runner = single_thread_task_runner_manager_
+                           ->CreateSingleThreadTaskRunnerWithTraits(
+                               TaskTraits().WithBaseSyncPrimitives());
+    EXPECT_TRUE(task_runner->PostTask(
+        FROM_HERE, Bind(&WaitableEvent::Signal, Unretained(&task_running))));
+    EXPECT_TRUE(task_runner->PostTask(
+        FROM_HERE, Bind(&WaitableEvent::Wait, Unretained(&task_blocking))));
+    EXPECT_TRUE(task_runner->PostTask(FROM_HERE, Bind(&DoNothing)));
+  }
+
+  task_running.Wait();
+  CallJoinFromDifferentThread join_from_different_thread(
+      single_thread_task_runner_manager_.get());
+  join_from_different_thread.Start();
+  join_from_different_thread.WaitForRunToStart();
+  task_blocking.Signal();
+  join_from_different_thread.Join();
+}
+
+}  // namespace internal
+}  // namespace base