Split ObserverListThreadSafe tests out into their own .cc file.
Apart from some simple classes (Foo, Adder), the existing test suites
really don't share very much code. After https://crrev.com/c/1053338
they will share even less. Split out the threaded tests to their own
file to reduce complexity.
This is largely a verbatim move (preserving order), apart from
whitespace changes.
Bug: 842987
Change-Id: I555662a5516add7267abd1608f54fd13cbd7d97c
Reviewed-on: https://chromium-review.googlesource.com/1175508
Reviewed-by: Gabriel Charette <[email protected]>
Commit-Queue: Trent Apted <[email protected]>
Cr-Commit-Position: refs/heads/master@{#583447}diff --git a/base/observer_list_threadsafe_unittest.cc b/base/observer_list_threadsafe_unittest.cc
new file mode 100644
index 0000000..64e273b
--- /dev/null
+++ b/base/observer_list_threadsafe_unittest.cc
@@ -0,0 +1,555 @@
+// Copyright 2018 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/observer_list_threadsafe.h"
+
+#include <memory>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/location.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/sequenced_task_runner.h"
+#include "base/single_thread_task_runner.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/task/post_task.h"
+#include "base/task/task_scheduler/task_scheduler.h"
+#include "base/test/scoped_task_environment.h"
+#include "base/threading/platform_thread.h"
+#include "base/threading/thread_restrictions.h"
+#include "build/build_config.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+namespace {
+
+constexpr int kThreadRunTime = 2000; // ms to run the multi-threaded test.
+
+class Foo {
+ public:
+ virtual void Observe(int x) = 0;
+ virtual ~Foo() = default;
+ virtual int GetValue() const { return 0; }
+};
+
+class Adder : public Foo {
+ public:
+ explicit Adder(int scaler) : total(0), scaler_(scaler) {}
+ ~Adder() override = default;
+
+ void Observe(int x) override { total += x * scaler_; }
+ int GetValue() const override { return total; }
+
+ int total;
+
+ private:
+ int scaler_;
+};
+
+class AddInObserve : public Foo {
+ public:
+ explicit AddInObserve(ObserverListThreadSafe<Foo>* observer_list)
+ : observer_list(observer_list), to_add_() {}
+
+ void SetToAdd(Foo* to_add) { to_add_ = to_add; }
+
+ void Observe(int x) override {
+ if (to_add_) {
+ observer_list->AddObserver(to_add_);
+ to_add_ = nullptr;
+ }
+ }
+
+ ObserverListThreadSafe<Foo>* observer_list;
+ Foo* to_add_;
+};
+
+// A thread for use in the ThreadSafeObserver test which will add and remove
+// itself from the notification list repeatedly.
+class AddRemoveThread : public PlatformThread::Delegate, public Foo {
+ public:
+ AddRemoveThread(ObserverListThreadSafe<Foo>* list,
+ bool notify,
+ WaitableEvent* ready)
+ : list_(list),
+ loop_(nullptr),
+ in_list_(false),
+ start_(Time::Now()),
+ count_observes_(0),
+ count_addtask_(0),
+ do_notifies_(notify),
+ ready_(ready),
+ weak_factory_(this) {}
+
+ ~AddRemoveThread() override = default;
+
+ void ThreadMain() override {
+ loop_ = new MessageLoop(); // Fire up a message loop.
+ loop_->task_runner()->PostTask(
+ FROM_HERE,
+ base::BindOnce(&AddRemoveThread::AddTask, weak_factory_.GetWeakPtr()));
+ ready_->Signal();
+ // After ready_ is signaled, loop_ is only accessed by the main test thread
+ // (i.e. not this thread) in particular by Quit() which causes Run() to
+ // return, and we "control" loop_ again.
+ RunLoop run_loop;
+ quit_loop_ = run_loop.QuitClosure();
+ run_loop.Run();
+ delete loop_;
+ loop_ = reinterpret_cast<MessageLoop*>(0xdeadbeef);
+ delete this;
+ }
+
+ // This task just keeps posting to itself in an attempt to race with the
+ // notifier.
+ void AddTask() {
+ count_addtask_++;
+
+ if ((Time::Now() - start_).InMilliseconds() > kThreadRunTime) {
+ VLOG(1) << "DONE!";
+ return;
+ }
+
+ if (!in_list_) {
+ list_->AddObserver(this);
+ in_list_ = true;
+ }
+
+ if (do_notifies_) {
+ list_->Notify(FROM_HERE, &Foo::Observe, 10);
+ }
+
+ loop_->task_runner()->PostTask(
+ FROM_HERE,
+ base::BindOnce(&AddRemoveThread::AddTask, weak_factory_.GetWeakPtr()));
+ }
+
+ // This function is only callable from the main thread.
+ void Quit() { std::move(quit_loop_).Run(); }
+
+ void Observe(int x) override {
+ count_observes_++;
+
+ // If we're getting called after we removed ourselves from the list, that is
+ // very bad!
+ DCHECK(in_list_);
+
+ // This callback should fire on the appropriate thread
+ EXPECT_EQ(loop_, MessageLoop::current());
+
+ list_->RemoveObserver(this);
+ in_list_ = false;
+ }
+
+ private:
+ ObserverListThreadSafe<Foo>* list_;
+ MessageLoop* loop_;
+ bool in_list_; // Are we currently registered for notifications.
+ // in_list_ is only used on |this| thread.
+ Time start_; // The time we started the test.
+
+ int count_observes_; // Number of times we observed.
+ int count_addtask_; // Number of times thread AddTask was called
+ bool do_notifies_; // Whether these threads should do notifications.
+ WaitableEvent* ready_;
+
+ base::OnceClosure quit_loop_;
+
+ base::WeakPtrFactory<AddRemoveThread> weak_factory_;
+};
+
+} // namespace
+
+TEST(ObserverListThreadSafeTest, BasicTest) {
+ MessageLoop loop;
+
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>);
+ Adder a(1);
+ Adder b(-1);
+ Adder c(1);
+ Adder d(-1);
+
+ observer_list->AddObserver(&a);
+ observer_list->AddObserver(&b);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 10);
+ RunLoop().RunUntilIdle();
+
+ observer_list->AddObserver(&c);
+ observer_list->AddObserver(&d);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 10);
+ observer_list->RemoveObserver(&c);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(20, a.total);
+ EXPECT_EQ(-20, b.total);
+ EXPECT_EQ(0, c.total);
+ EXPECT_EQ(-10, d.total);
+}
+
+TEST(ObserverListThreadSafeTest, RemoveObserver) {
+ MessageLoop loop;
+
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>);
+ Adder a(1), b(1);
+
+ // A workaround for the compiler bug. See http://crbug.com/121960.
+ EXPECT_NE(&a, &b);
+
+ // Should do nothing.
+ observer_list->RemoveObserver(&a);
+ observer_list->RemoveObserver(&b);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 10);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(0, a.total);
+ EXPECT_EQ(0, b.total);
+
+ observer_list->AddObserver(&a);
+
+ // Should also do nothing.
+ observer_list->RemoveObserver(&b);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 10);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(10, a.total);
+ EXPECT_EQ(0, b.total);
+}
+
+TEST(ObserverListThreadSafeTest, WithoutSequence) {
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>);
+
+ Adder a(1), b(1), c(1);
+
+ // No sequence, so these should not be added.
+ observer_list->AddObserver(&a);
+ observer_list->AddObserver(&b);
+
+ {
+ // Add c when there's a sequence.
+ MessageLoop loop;
+ observer_list->AddObserver(&c);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 10);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(0, a.total);
+ EXPECT_EQ(0, b.total);
+ EXPECT_EQ(10, c.total);
+
+ // Now add a when there's a sequence.
+ observer_list->AddObserver(&a);
+
+ // Remove c when there's a sequence.
+ observer_list->RemoveObserver(&c);
+
+ // Notify again.
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 20);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(20, a.total);
+ EXPECT_EQ(0, b.total);
+ EXPECT_EQ(10, c.total);
+ }
+
+ // Removing should always succeed with or without a sequence.
+ observer_list->RemoveObserver(&a);
+
+ // Notifying should not fail but should also be a no-op.
+ MessageLoop loop;
+ observer_list->AddObserver(&b);
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 30);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(20, a.total);
+ EXPECT_EQ(30, b.total);
+ EXPECT_EQ(10, c.total);
+}
+
+class FooRemover : public Foo {
+ public:
+ explicit FooRemover(ObserverListThreadSafe<Foo>* list) : list_(list) {}
+ ~FooRemover() override = default;
+
+ void AddFooToRemove(Foo* foo) { foos_.push_back(foo); }
+
+ void Observe(int x) override {
+ std::vector<Foo*> tmp;
+ tmp.swap(foos_);
+ for (std::vector<Foo*>::iterator it = tmp.begin(); it != tmp.end(); ++it) {
+ list_->RemoveObserver(*it);
+ }
+ }
+
+ private:
+ const scoped_refptr<ObserverListThreadSafe<Foo>> list_;
+ std::vector<Foo*> foos_;
+};
+
+TEST(ObserverListThreadSafeTest, RemoveMultipleObservers) {
+ MessageLoop loop;
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>);
+
+ FooRemover a(observer_list.get());
+ Adder b(1);
+
+ observer_list->AddObserver(&a);
+ observer_list->AddObserver(&b);
+
+ a.AddFooToRemove(&a);
+ a.AddFooToRemove(&b);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+ RunLoop().RunUntilIdle();
+}
+
+// A test driver for a multi-threaded notification loop. Runs a number of
+// observer threads, each of which constantly adds/removes itself from the
+// observer list. Optionally, if cross_thread_notifies is set to true, the
+// observer threads will also trigger notifications to all observers.
+static void ThreadSafeObserverHarness(int num_threads,
+ bool cross_thread_notifies) {
+ MessageLoop loop;
+
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>);
+ Adder a(1);
+ Adder b(-1);
+
+ observer_list->AddObserver(&a);
+ observer_list->AddObserver(&b);
+
+ std::vector<AddRemoveThread*> threaded_observer;
+ std::vector<base::PlatformThreadHandle> threads(num_threads);
+ std::vector<std::unique_ptr<base::WaitableEvent>> ready;
+ threaded_observer.reserve(num_threads);
+ ready.reserve(num_threads);
+ for (int index = 0; index < num_threads; index++) {
+ ready.push_back(std::make_unique<WaitableEvent>(
+ WaitableEvent::ResetPolicy::MANUAL,
+ WaitableEvent::InitialState::NOT_SIGNALED));
+ threaded_observer.push_back(new AddRemoveThread(
+ observer_list.get(), cross_thread_notifies, ready.back().get()));
+ EXPECT_TRUE(
+ PlatformThread::Create(0, threaded_observer.back(), &threads[index]));
+ }
+ ASSERT_EQ(static_cast<size_t>(num_threads), threaded_observer.size());
+ ASSERT_EQ(static_cast<size_t>(num_threads), ready.size());
+
+ // This makes sure that threaded_observer has gotten to set loop_, so that we
+ // can call Quit() below safe-ish-ly.
+ for (int i = 0; i < num_threads; ++i)
+ ready[i]->Wait();
+
+ Time start = Time::Now();
+ while (true) {
+ if ((Time::Now() - start).InMilliseconds() > kThreadRunTime)
+ break;
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 10);
+
+ RunLoop().RunUntilIdle();
+ }
+
+ for (int index = 0; index < num_threads; index++) {
+ threaded_observer[index]->Quit();
+ PlatformThread::Join(threads[index]);
+ }
+}
+
+#if defined(OS_FUCHSIA)
+// TODO(crbug.com/738275): This is flaky on Fuchsia.
+#define MAYBE_CrossThreadObserver DISABLED_CrossThreadObserver
+#else
+#define MAYBE_CrossThreadObserver CrossThreadObserver
+#endif
+TEST(ObserverListThreadSafeTest, MAYBE_CrossThreadObserver) {
+ // Use 7 observer threads. Notifications only come from the main thread.
+ ThreadSafeObserverHarness(7, false);
+}
+
+TEST(ObserverListThreadSafeTest, CrossThreadNotifications) {
+ // Use 3 observer threads. Notifications will fire from the main thread and
+ // all 3 observer threads.
+ ThreadSafeObserverHarness(3, true);
+}
+
+TEST(ObserverListThreadSafeTest, OutlivesMessageLoop) {
+ MessageLoop* loop = new MessageLoop;
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>);
+
+ Adder a(1);
+ observer_list->AddObserver(&a);
+ delete loop;
+ // Test passes if we don't crash here.
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+}
+
+namespace {
+
+class SequenceVerificationObserver : public Foo {
+ public:
+ explicit SequenceVerificationObserver(
+ scoped_refptr<SequencedTaskRunner> task_runner)
+ : task_runner_(std::move(task_runner)) {}
+ ~SequenceVerificationObserver() override = default;
+
+ void Observe(int x) override {
+ called_on_valid_sequence_ = task_runner_->RunsTasksInCurrentSequence();
+ }
+
+ bool called_on_valid_sequence() const { return called_on_valid_sequence_; }
+
+ private:
+ const scoped_refptr<SequencedTaskRunner> task_runner_;
+ bool called_on_valid_sequence_ = false;
+
+ DISALLOW_COPY_AND_ASSIGN(SequenceVerificationObserver);
+};
+
+} // namespace
+
+// Verify that observers are notified on the correct sequence.
+TEST(ObserverListThreadSafeTest, NotificationOnValidSequence) {
+ test::ScopedTaskEnvironment scoped_task_environment;
+
+ auto task_runner_1 = CreateSequencedTaskRunnerWithTraits(TaskTraits());
+ auto task_runner_2 = CreateSequencedTaskRunnerWithTraits(TaskTraits());
+
+ auto observer_list = MakeRefCounted<ObserverListThreadSafe<Foo>>();
+
+ SequenceVerificationObserver observer_1(task_runner_1);
+ SequenceVerificationObserver observer_2(task_runner_2);
+
+ task_runner_1->PostTask(FROM_HERE,
+ BindOnce(&ObserverListThreadSafe<Foo>::AddObserver,
+ observer_list, Unretained(&observer_1)));
+ task_runner_2->PostTask(FROM_HERE,
+ BindOnce(&ObserverListThreadSafe<Foo>::AddObserver,
+ observer_list, Unretained(&observer_2)));
+
+ TaskScheduler::GetInstance()->FlushForTesting();
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+
+ TaskScheduler::GetInstance()->FlushForTesting();
+
+ EXPECT_TRUE(observer_1.called_on_valid_sequence());
+ EXPECT_TRUE(observer_2.called_on_valid_sequence());
+}
+
+// Verify that when an observer is added to a NOTIFY_ALL ObserverListThreadSafe
+// from a notification, it is itself notified.
+TEST(ObserverListThreadSafeTest, AddObserverFromNotificationNotifyAll) {
+ test::ScopedTaskEnvironment scoped_task_environment;
+ auto observer_list = MakeRefCounted<ObserverListThreadSafe<Foo>>();
+
+ Adder observer_added_from_notification(1);
+
+ AddInObserve initial_observer(observer_list.get());
+ initial_observer.SetToAdd(&observer_added_from_notification);
+ observer_list->AddObserver(&initial_observer);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+
+ base::RunLoop().RunUntilIdle();
+
+ EXPECT_EQ(1, observer_added_from_notification.GetValue());
+}
+
+namespace {
+
+class RemoveWhileNotificationIsRunningObserver : public Foo {
+ public:
+ RemoveWhileNotificationIsRunningObserver()
+ : notification_running_(WaitableEvent::ResetPolicy::AUTOMATIC,
+ WaitableEvent::InitialState::NOT_SIGNALED),
+ barrier_(WaitableEvent::ResetPolicy::AUTOMATIC,
+ WaitableEvent::InitialState::NOT_SIGNALED) {}
+ ~RemoveWhileNotificationIsRunningObserver() override = default;
+
+ void Observe(int x) override {
+ notification_running_.Signal();
+ ScopedAllowBaseSyncPrimitivesForTesting allow_base_sync_primitives;
+ barrier_.Wait();
+ }
+
+ void WaitForNotificationRunning() { notification_running_.Wait(); }
+ void Unblock() { barrier_.Signal(); }
+
+ private:
+ WaitableEvent notification_running_;
+ WaitableEvent barrier_;
+
+ DISALLOW_COPY_AND_ASSIGN(RemoveWhileNotificationIsRunningObserver);
+};
+
+} // namespace
+
+// Verify that there is no crash when an observer is removed while it is being
+// notified.
+TEST(ObserverListThreadSafeTest, RemoveWhileNotificationIsRunning) {
+ auto observer_list = MakeRefCounted<ObserverListThreadSafe<Foo>>();
+ RemoveWhileNotificationIsRunningObserver observer;
+
+ WaitableEvent task_running(WaitableEvent::ResetPolicy::AUTOMATIC,
+ WaitableEvent::InitialState::NOT_SIGNALED);
+ WaitableEvent barrier(WaitableEvent::ResetPolicy::AUTOMATIC,
+ WaitableEvent::InitialState::NOT_SIGNALED);
+
+ // This must be after the declaration of |barrier| so that tasks posted to
+ // TaskScheduler can safely use |barrier|.
+ test::ScopedTaskEnvironment scoped_task_environment;
+
+ CreateSequencedTaskRunnerWithTraits({})->PostTask(
+ FROM_HERE, base::BindOnce(&ObserverListThreadSafe<Foo>::AddObserver,
+ observer_list, Unretained(&observer)));
+ TaskScheduler::GetInstance()->FlushForTesting();
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+ observer.WaitForNotificationRunning();
+ observer_list->RemoveObserver(&observer);
+
+ observer.Unblock();
+}
+
+// Same as ObserverListTest.Existing, but for ObserverListThreadSafe
+TEST(ObserverListThreadSafeTest, Existing) {
+ MessageLoop loop;
+ scoped_refptr<ObserverListThreadSafe<Foo>> observer_list(
+ new ObserverListThreadSafe<Foo>(ObserverListPolicy::EXISTING_ONLY));
+ Adder a(1);
+ AddInObserve b(observer_list.get());
+ Adder c(1);
+ b.SetToAdd(&c);
+
+ observer_list->AddObserver(&a);
+ observer_list->AddObserver(&b);
+
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+ RunLoop().RunUntilIdle();
+
+ EXPECT_FALSE(b.to_add_);
+ // B's adder should not have been notified because it was added during
+ // notification.
+ EXPECT_EQ(0, c.total);
+
+ // Notify again to make sure b's adder is notified.
+ observer_list->Notify(FROM_HERE, &Foo::Observe, 1);
+ RunLoop().RunUntilIdle();
+ EXPECT_EQ(1, c.total);
+}
+
+} // namespace base
