text: // Copyright (c) 2012 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/threading/thread.h"
  
  #include <stddef.h>
  
  #include <vector>
  
  #include "base/bind.h"
  #include "base/location.h"
  #include "base/single_thread_task_runner.h"
  #include "base/synchronization/waitable_event.h"
  #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
  #include "build/build_config.h"
  #include "testing/gtest/include/gtest/gtest.h"
  #include "testing/platform_test.h"
  
  using base::Thread;
  
  typedef PlatformTest ThreadTest;
  
  namespace {
  
  void ToggleValue(bool* value) {
    ANNOTATE_BENIGN_RACE(value, "Test-only data race on boolean "
                         "in base/thread_unittest");
    *value = !*value;
  }
  
  class SleepInsideInitThread : public Thread {
   public:
    SleepInsideInitThread() : Thread("none") {
      init_called_ = false;
      ANNOTATE_BENIGN_RACE(
          this, "Benign test-only data race on vptr - http://crbug.com/98219");
    }
    ~SleepInsideInitThread() override { Stop(); }
  
    void Init() override {
      base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(500));
      init_called_ = true;
    }
    bool InitCalled() { return init_called_; }
   private:
    bool init_called_;
  };
  
  enum ThreadEvent {
    // Thread::Init() was called.
    THREAD_EVENT_INIT = 0,
  
    // The MessageLoop for the thread was deleted.
    THREAD_EVENT_MESSAGE_LOOP_DESTROYED,
  
    // Thread::CleanUp() was called.
    THREAD_EVENT_CLEANUP,
  
    // Keep at end of list.
    THREAD_NUM_EVENTS
  };
  
  typedef std::vector<ThreadEvent> EventList;
  
  class CaptureToEventList : public Thread {
   public:
    // This Thread pushes events into the vector |event_list| to show
    // the order they occured in. |event_list| must remain valid for the
    // lifetime of this thread.
    explicit CaptureToEventList(EventList* event_list)
        : Thread("none"),
          event_list_(event_list) {
    }
  
    ~CaptureToEventList() override { Stop(); }
  
    void Init() override { event_list_->push_back(THREAD_EVENT_INIT); }
  
    void CleanUp() override { event_list_->push_back(THREAD_EVENT_CLEANUP); }
  
   private:
    EventList* event_list_;
  };
  
  // Observer that writes a value into |event_list| when a message loop has been
  // destroyed.
  class CapturingDestructionObserver
      : public base::MessageLoop::DestructionObserver {
   public:
    // |event_list| must remain valid throughout the observer's lifetime.
    explicit CapturingDestructionObserver(EventList* event_list)
        : event_list_(event_list) {
    }
  
    // DestructionObserver implementation:
    void WillDestroyCurrentMessageLoop() override {
      event_list_->push_back(THREAD_EVENT_MESSAGE_LOOP_DESTROYED);
      event_list_ = NULL;
    }
  
   private:
    EventList* event_list_;
  };
  
  // Task that adds a destruction observer to the current message loop.
  void RegisterDestructionObserver(
      base::MessageLoop::DestructionObserver* observer) {
    base::MessageLoop::current()->AddDestructionObserver(observer);
  }
  
  // Task that calls GetThreadId() of |thread|, stores the result into |id|, then
  // signal |event|.
  void ReturnThreadId(base::Thread* thread,
                      base::PlatformThreadId* id,
                      base::WaitableEvent* event) {
    *id = thread->GetThreadId();
    event->Signal();
  }
  
  }  // namespace
  
  TEST_F(ThreadTest, Restart) {
    Thread a("Restart");
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
    EXPECT_TRUE(a.Start());
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
    EXPECT_TRUE(a.Start());
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
  }
  
  TEST_F(ThreadTest, StartWithOptions_StackSize) {
    Thread a("StartWithStackSize");
    // Ensure that the thread can work with only 12 kb and still process a
    // message.
    Thread::Options options;
  #if defined(ADDRESS_SANITIZER)
    // ASan bloats the stack variables and overflows the 12 kb stack.
    options.stack_size = 24*1024;
  #else
    options.stack_size = 12*1024;
  #endif
    EXPECT_TRUE(a.StartWithOptions(options));
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
  
    bool was_invoked = false;
    a.task_runner()->PostTask(FROM_HERE, base::Bind(&ToggleValue, &was_invoked));
  
    // wait for the task to run (we could use a kernel event here
    // instead to avoid busy waiting, but this is sufficient for
    // testing purposes).
    for (int i = 100; i >= 0 && !was_invoked; --i) {
      base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(10));
    }
    EXPECT_TRUE(was_invoked);
  }
  
  TEST_F(ThreadTest, TwoTasks) {
    bool was_invoked = false;
    {
      Thread a("TwoTasks");
      EXPECT_TRUE(a.Start());
      EXPECT_TRUE(a.message_loop());
  
      // Test that all events are dispatched before the Thread object is
      // destroyed.  We do this by dispatching a sleep event before the
      // event that will toggle our sentinel value.
      a.task_runner()->PostTask(
          FROM_HERE, base::Bind(static_cast<void (*)(base::TimeDelta)>(
                                    &base::PlatformThread::Sleep),
                                base::TimeDelta::FromMilliseconds(20)));
      a.task_runner()->PostTask(FROM_HERE,
                                base::Bind(&ToggleValue, &was_invoked));
    }
    EXPECT_TRUE(was_invoked);
  }
  
  TEST_F(ThreadTest, StopSoon) {
    Thread a("StopSoon");
    EXPECT_TRUE(a.Start());
    EXPECT_TRUE(a.message_loop());
    EXPECT_TRUE(a.IsRunning());
    a.StopSoon();
    a.StopSoon();
    a.Stop();
    EXPECT_FALSE(a.message_loop());
    EXPECT_FALSE(a.IsRunning());
  }
  
  TEST_F(ThreadTest, ThreadName) {
    Thread a("ThreadName");
    EXPECT_TRUE(a.Start());
    EXPECT_EQ("ThreadName", a.thread_name());
  }
  
  TEST_F(ThreadTest, ThreadId) {
    Thread a("ThreadId0");
    Thread b("ThreadId1");
    a.Start();
    b.Start();
  
    // Post a task that calls GetThreadId() on the created thread.
    base::WaitableEvent event(false, false);
    base::PlatformThreadId id_from_new_thread;
    a.task_runner()->PostTask(
        FROM_HERE, base::Bind(ReturnThreadId, &a, &id_from_new_thread, &event));
  
    // Call GetThreadId() on the current thread before calling event.Wait() so
    // that this test can find a race issue with TSAN.
    base::PlatformThreadId id_from_current_thread = a.GetThreadId();
  
    // Check if GetThreadId() returns consistent value in both threads.
    event.Wait();
    EXPECT_EQ(id_from_current_thread, id_from_new_thread);
  
    // A started thread should have a valid ID.
    EXPECT_NE(base::kInvalidThreadId, a.GetThreadId());
    EXPECT_NE(base::kInvalidThreadId, b.GetThreadId());
  
    // Each thread should have a different thread ID.
    EXPECT_NE(a.GetThreadId(), b.GetThreadId());
  }
  
  TEST_F(ThreadTest, ThreadIdWithRestart) {
    Thread a("ThreadIdWithRestart");
    base::PlatformThreadId previous_id = base::kInvalidThreadId;
  
    for (size_t i = 0; i < 16; ++i) {
      EXPECT_TRUE(a.Start());
      base::PlatformThreadId current_id = a.GetThreadId();
      EXPECT_NE(previous_id, current_id);
      previous_id = current_id;
      a.Stop();
    }
  }
  
  // Make sure Init() is called after Start() and before
  // WaitUntilThreadInitialized() returns.
  TEST_F(ThreadTest, SleepInsideInit) {
    SleepInsideInitThread t;
    EXPECT_FALSE(t.InitCalled());
    t.StartAndWaitForTesting();
    EXPECT_TRUE(t.InitCalled());
  }
  
  // Make sure that the destruction sequence is:
  //
  //  (1) Thread::CleanUp()
  //  (2) MessageLoop::~MessageLoop()
  //      MessageLoop::DestructionObservers called.
  TEST_F(ThreadTest, CleanUp) {
    EventList captured_events;
    CapturingDestructionObserver loop_destruction_observer(&captured_events);
  
    {
      // Start a thread which writes its event into |captured_events|.
      CaptureToEventList t(&captured_events);
      EXPECT_TRUE(t.Start());
      EXPECT_TRUE(t.message_loop());
      EXPECT_TRUE(t.IsRunning());
  
      // Register an observer that writes into |captured_events| once the
      // thread's message loop is destroyed.
      t.task_runner()->PostTask(
          FROM_HERE, base::Bind(&RegisterDestructionObserver,
                                base::Unretained(&loop_destruction_observer)));
  
      // Upon leaving this scope, the thread is deleted.
    }
  
    // Check the order of events during shutdown.
    ASSERT_EQ(static_cast<size_t>(THREAD_NUM_EVENTS), captured_events.size());
    EXPECT_EQ(THREAD_EVENT_INIT, captured_events[0]);
    EXPECT_EQ(THREAD_EVENT_CLEANUP, captured_events[1]);
    EXPECT_EQ(THREAD_EVENT_MESSAGE_LOOP_DESTROYED, captured_events[2]);
  }
  
  TEST_F(ThreadTest, ThreadNotStarted) {
    Thread a("Inert");
    EXPECT_EQ(nullptr, a.task_runner());
  }
  
  TEST_F(ThreadTest, MultipleWaitUntilThreadStarted) {
    Thread a("MultipleWaitUntilThreadStarted");
    EXPECT_TRUE(a.Start());
    // It's OK to call WaitUntilThreadStarted() multiple times.
    EXPECT_TRUE(a.WaitUntilThreadStarted());
    EXPECT_TRUE(a.WaitUntilThreadStarted());
  }
  