components: Introduce AlarmTimer class and use it for GCM heartbeat

components/timer/alarm_timer_unittest.cc

Index: components/timer/alarm_timer_unittest.cc
diff --git a/components/timer/alarm_timer_unittest.cc b/components/timer/alarm_timer_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..37a169885a4d57791d6d0ab65908e0875eaf2a05
--- /dev/null
+++ b/components/timer/alarm_timer_unittest.cc
@@ -0,0 +1,493 @@
+// Copyright 2014 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/bind.h"
+#include "base/bind_helpers.h"
+#include "base/macros.h"
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "base/threading/platform_thread.h"
+#include "base/time/time.h"
+#include "components/timer/alarm_timer.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+// Most of these tests have been lifted right out of timer_unittest.cc with only
+// cosmetic changes (like replacing calls to MessageLoop::current()->Run() with
+// a RunLoop).  We want the AlarmTimer to be a drop-in replacement for the
+// regular Timer so it should pass the same tests as the Timer class.

[Daniel Erat, 2014/10/23 03:44:54]

i don't love the duplication here but don't have any better suggestions (unless
there's some way to refactor the testing code so it can be shared).

[blundell, 2014/10/23 05:54:20]

This duplication seems pretty bad. Could you reach out to the person with the
most expertise in base/timer to get some ideas on refactoring? Doesn't need to
block this CL.

[Chirantan Ekbote, 2014/10/23 23:53:30]

I've filed crbug.com/426647.  We'll land this for now and then figure out how to
refactor it.

+//
+// The only new tests are the .*ConcurrentResetAndTimerFired tests, which test
+// that race conditions that can come up in the AlarmTimer::Delegate are
+// properly handled.
+namespace {
+// The message loops on which each timer should be tested.
+const base::MessageLoop::Type testing_message_loops[] = {
+  base::MessageLoop::TYPE_DEFAULT,
+  base::MessageLoop::TYPE_IO,
+#if !defined(OS_IOS)  // iOS does not allow direct running of the UI loop.
+  base::MessageLoop::TYPE_UI,
+#endif
+};
+
+const int kNumTestingMessageLoops = arraysize(testing_message_loops);
+const base::TimeDelta kTenMilliseconds = base::TimeDelta::FromMilliseconds(10);
+
+class OneShotAlarmTimerTester {
+ public:
+  OneShotAlarmTimerTester(bool* did_run, base::TimeDelta delay)
+      : did_run_(did_run),
+        delay_(delay),
+        timer_(new timer::AlarmTimer(false, false)) {
+  }
+  void Start() {
+    timer_->Start(FROM_HERE,
+                  delay_,
+                  base::Bind(&OneShotAlarmTimerTester::Run,
+                             base::Unretained(this)));
+  }
+
+ private:
+  void Run() {
+    *did_run_ = true;
+
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+  }
+
+  bool* did_run_;
+  const base::TimeDelta delay_;
+  scoped_ptr<timer::AlarmTimer> timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(OneShotAlarmTimerTester);
+};
+
+class OneShotSelfDeletingAlarmTimerTester {
+ public:
+  OneShotSelfDeletingAlarmTimerTester(bool* did_run, base::TimeDelta delay)
+      : did_run_(did_run),
+        delay_(delay),
+        timer_(new timer::AlarmTimer(false, false)) {
+  }
+  void Start() {
+    timer_->Start(FROM_HERE,
+                  delay_,
+                  base::Bind(&OneShotSelfDeletingAlarmTimerTester::Run,
+                             base::Unretained(this)));
+  }
+
+ private:
+  void Run() {
+    *did_run_ = true;
+    timer_.reset();
+
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+  }
+
+  bool* did_run_;
+  const base::TimeDelta delay_;
+  scoped_ptr<timer::AlarmTimer> timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(OneShotSelfDeletingAlarmTimerTester);
+};
+
+class RepeatingAlarmTimerTester {
+ public:
+  RepeatingAlarmTimerTester(bool* did_run, base::TimeDelta delay)
+      : did_run_(did_run),
+        delay_(delay),
+        counter_(10),
+        timer_(new timer::AlarmTimer(true, true)) {
+  }
+  void Start() {
+    timer_->Start(FROM_HERE,
+                  delay_,
+                  base::Bind(&RepeatingAlarmTimerTester::Run,
+                             base::Unretained(this)));
+  }
+
+ private:
+  void Run() {
+    if (--counter_ == 0) {
+      *did_run_ = true;
+      timer_->Stop();
+
+      base::MessageLoop::current()->PostTask(
+          FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+    }
+  }
+
+  bool* did_run_;
+  const base::TimeDelta delay_;
+  int counter_;
+  scoped_ptr<timer::AlarmTimer> timer_;
+
+  DISALLOW_COPY_AND_ASSIGN(RepeatingAlarmTimerTester);
+};
+
+void RunTest_OneShotAlarmTimer(base::MessageLoop::Type message_loop_type) {
+  base::MessageLoop loop(message_loop_type);
+
+  bool did_run = false;
+  OneShotAlarmTimerTester f(&did_run, kTenMilliseconds);
+  f.Start();
+
+  base::RunLoop().Run();
+
+  EXPECT_TRUE(did_run);
+}
+
+void RunTest_OneShotAlarmTimer_Cancel(
+    base::MessageLoop::Type message_loop_type) {
+  base::MessageLoop loop(message_loop_type);
+
+  bool did_run_a = false;
+  OneShotAlarmTimerTester* a = new OneShotAlarmTimerTester(&did_run_a,
+                                                           kTenMilliseconds);
+
+  // This should run before the timer expires.
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, a);
+
+  // Now start the timer.
+  a->Start();
+
+  bool did_run_b = false;
+  OneShotAlarmTimerTester b(&did_run_b, kTenMilliseconds);
+  b.Start();
+
+  base::RunLoop().Run();
+
+  EXPECT_FALSE(did_run_a);
+  EXPECT_TRUE(did_run_b);
+}
+
+void RunTest_OneShotSelfDeletingAlarmTimer(
+    base::MessageLoop::Type message_loop_type) {
+  base::MessageLoop loop(message_loop_type);
+
+  bool did_run = false;
+  OneShotSelfDeletingAlarmTimerTester f(&did_run, kTenMilliseconds);
+  f.Start();
+
+  base::RunLoop().Run();
+
+  EXPECT_TRUE(did_run);
+}
+
+void RunTest_RepeatingAlarmTimer(base::MessageLoop::Type message_loop_type,
+                                 const base::TimeDelta& delay) {
+  base::MessageLoop loop(message_loop_type);
+
+  bool did_run = false;
+  RepeatingAlarmTimerTester f(&did_run, delay);
+  f.Start();
+
+  base::RunLoop().Run();
+
+  EXPECT_TRUE(did_run);
+}
+
+void RunTest_RepeatingAlarmTimer_Cancel(
+    base::MessageLoop::Type message_loop_type, const base::TimeDelta& delay) {
+  base::MessageLoop loop(message_loop_type);
+
+  bool did_run_a = false;
+  RepeatingAlarmTimerTester* a = new RepeatingAlarmTimerTester(&did_run_a,
+                                                               delay);
+
+  // This should run before the timer expires.
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, a);
+
+  // Now start the timer.
+  a->Start();
+
+  bool did_run_b = false;
+  RepeatingAlarmTimerTester b(&did_run_b, delay);
+  b.Start();
+
+  base::RunLoop().Run();
+
+  EXPECT_FALSE(did_run_a);
+  EXPECT_TRUE(did_run_b);
+}
+
+}  // namespace
+
+//-----------------------------------------------------------------------------
+// Each test is run against each type of MessageLoop.  That way we are sure
+// that timers work properly in all configurations.
+
+TEST(AlarmTimerTest, OneShotAlarmTimer) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_OneShotAlarmTimer(testing_message_loops[i]);
+  }
+}
+
+TEST(AlarmTimerTest, OneShotAlarmTimer_Cancel) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_OneShotAlarmTimer_Cancel(testing_message_loops[i]);
+  }
+}
+
+// If underlying timer does not handle this properly, we will crash or fail
+// in full page heap environment.
+TEST(AlarmTimerTest, OneShotSelfDeletingAlarmTimer) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_OneShotSelfDeletingAlarmTimer(testing_message_loops[i]);
+  }
+}
+
+TEST(AlarmTimerTest, RepeatingAlarmTimer) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_RepeatingAlarmTimer(testing_message_loops[i],
+                                kTenMilliseconds);
+  }
+}
+
+TEST(AlarmTimerTest, RepeatingAlarmTimer_Cancel) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_RepeatingAlarmTimer_Cancel(testing_message_loops[i],
+                                       kTenMilliseconds);
+  }
+}
+
+TEST(AlarmTimerTest, RepeatingAlarmTimerZeroDelay) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_RepeatingAlarmTimer(testing_message_loops[i],
+                                base::TimeDelta::FromMilliseconds(0));
+  }
+}
+
+TEST(AlarmTimerTest, RepeatingAlarmTimerZeroDelay_Cancel) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_RepeatingAlarmTimer_Cancel(testing_message_loops[i],
+                                       base::TimeDelta::FromMilliseconds(0));
+  }
+}
+
+TEST(AlarmTimerTest, MessageLoopShutdown) {
+  // This test is designed to verify that shutdown of the
+  // message loop does not cause crashes if there were pending
+  // timers not yet fired.  It may only trigger exceptions
+  // if debug heap checking is enabled.
+  bool did_run = false;
+  {
+    OneShotAlarmTimerTester a(&did_run, kTenMilliseconds);
+    OneShotAlarmTimerTester b(&did_run, kTenMilliseconds);
+    OneShotAlarmTimerTester c(&did_run, kTenMilliseconds);
+    OneShotAlarmTimerTester d(&did_run, kTenMilliseconds);
+    {
+      base::MessageLoop loop;
+      a.Start();
+      b.Start();
+    }  // MessageLoop destructs by falling out of scope.
+  }  // OneShotTimers destruct.  SHOULD NOT CRASH, of course.
+
+  EXPECT_FALSE(did_run);
+}
+
+TEST(AlarmTimerTest, NonRepeatIsRunning) {
+  {
+    base::MessageLoop loop;
+    timer::AlarmTimer timer(false, false);
+    EXPECT_FALSE(timer.IsRunning());
+    timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
+                base::Bind(&base::DoNothing));
+    EXPECT_TRUE(timer.IsRunning());
+    timer.Stop();
+    EXPECT_FALSE(timer.IsRunning());
+    EXPECT_TRUE(timer.user_task().is_null());
+  }
+
+  {
+    timer::AlarmTimer timer(true, false);
+    base::MessageLoop loop;
+    EXPECT_FALSE(timer.IsRunning());
+    timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
+                base::Bind(&base::DoNothing));
+    EXPECT_TRUE(timer.IsRunning());
+    timer.Stop();
+    EXPECT_FALSE(timer.IsRunning());
+    ASSERT_FALSE(timer.user_task().is_null());
+    timer.Reset();
+    EXPECT_TRUE(timer.IsRunning());
+  }
+}
+
+TEST(AlarmTimerTest, NonRepeatMessageLoopDeath) {
+  timer::AlarmTimer timer(false, false);
+  {
+    base::MessageLoop loop;
+    EXPECT_FALSE(timer.IsRunning());
+    timer.Start(FROM_HERE, base::TimeDelta::FromDays(1),
+                base::Bind(&base::DoNothing));
+    EXPECT_TRUE(timer.IsRunning());
+  }
+  EXPECT_FALSE(timer.IsRunning());
+  EXPECT_TRUE(timer.user_task().is_null());
+}
+
+TEST(AlarmTimerTest, RetainRepeatIsRunning) {
+  base::MessageLoop loop;
+  timer::AlarmTimer timer(FROM_HERE, base::TimeDelta::FromDays(1),
+                          base::Bind(&base::DoNothing), true);
+  EXPECT_FALSE(timer.IsRunning());
+  timer.Reset();
+  EXPECT_TRUE(timer.IsRunning());
+  timer.Stop();
+  EXPECT_FALSE(timer.IsRunning());
+  timer.Reset();
+  EXPECT_TRUE(timer.IsRunning());
+}
+
+TEST(AlarmTimerTest, RetainNonRepeatIsRunning) {
+  base::MessageLoop loop;
+  timer::AlarmTimer timer(FROM_HERE, base::TimeDelta::FromDays(1),
+                          base::Bind(&base::DoNothing), false);
+  EXPECT_FALSE(timer.IsRunning());
+  timer.Reset();
+  EXPECT_TRUE(timer.IsRunning());
+  timer.Stop();
+  EXPECT_FALSE(timer.IsRunning());
+  timer.Reset();
+  EXPECT_TRUE(timer.IsRunning());
+}
+
+namespace {
+
+bool g_callback_happened1 = false;
+bool g_callback_happened2 = false;
+
+void ClearAllCallbackHappened() {
+  g_callback_happened1 = false;
+  g_callback_happened2 = false;
+}
+
+void SetCallbackHappened1() {
+  g_callback_happened1 = true;
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+}
+
+void SetCallbackHappened2() {
+  g_callback_happened2 = true;
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+}
+
+TEST(AlarmTimerTest, ContinuationStopStart) {
+  {
+    ClearAllCallbackHappened();
+    base::MessageLoop loop;
+    timer::AlarmTimer timer(false, false);
+    timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(10),
+                base::Bind(&SetCallbackHappened1));
+    timer.Stop();
+    timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(40),
+                base::Bind(&SetCallbackHappened2));
+    base::RunLoop().Run();
+    EXPECT_FALSE(g_callback_happened1);
+    EXPECT_TRUE(g_callback_happened2);
+  }
+}
+
+TEST(AlarmTimerTest, ContinuationReset) {
+  {
+    ClearAllCallbackHappened();
+    base::MessageLoop loop;
+    timer::AlarmTimer timer(false, false);
+    timer.Start(FROM_HERE, base::TimeDelta::FromMilliseconds(10),
+                base::Bind(&SetCallbackHappened1));
+    timer.Reset();
+    // Since Reset happened before task ran, the user_task must not be cleared:
+    ASSERT_FALSE(timer.user_task().is_null());
+    base::RunLoop().Run();
+    EXPECT_TRUE(g_callback_happened1);
+  }
+}
+
+}  // namespace
+
+
+namespace {
+void TimerRanCallback(bool* did_run) {
+  *did_run = true;
+
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE, base::MessageLoop::QuitWhenIdleClosure());
+}
+
+void RunTest_OneShotTimerConcurrentResetAndTimerFired(
+    base::MessageLoop::Type message_loop_type) {
+  base::MessageLoop loop(message_loop_type);
+
+  timer::AlarmTimer timer(false, false);
+  bool did_run = false;
+
+  timer.Start(
+      FROM_HERE, kTenMilliseconds, base::Bind(&TimerRanCallback, &did_run));
+
+  // Sleep twice as long as the timer to ensure that the timer task gets queued.
+  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(20));
+
+  // Now reset the timer.  This is attempting to simulate the timer firing and
+  // being reset at the same time.  The previously queued task should be
+  // removed.
+  timer.Reset();
+
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(did_run);
+
+  // If the previous check failed, running the message loop again will hang the
+  // test so we only do it if the callback has not run yet.
+  if (!did_run) {
+    base::RunLoop().Run();
+    EXPECT_TRUE(did_run);
+  }
+}
+
+void RunTest_RepeatingTimerConcurrentResetAndTimerFired(
+    base::MessageLoop::Type message_loop_type) {
+  base::MessageLoop loop(message_loop_type);
+
+  timer::AlarmTimer timer(true, true);
+  bool did_run = false;
+
+  timer.Start(
+      FROM_HERE, kTenMilliseconds, base::Bind(&TimerRanCallback, &did_run));
+
+  // Sleep more that three times as long as the timer duration to ensure that
+  // multiple tasks get queued.
+  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(35));
+
+  // Now reset the timer.  This is attempting to simulate a very busy message
+  // loop where multiple tasks get queued but the timer gets reset before any of
+  // them have a chance to run.
+  timer.Reset();
+
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(did_run);
+
+  // If the previous check failed, running the message loop again will hang the
+  // test so we only do it if the callback has not run yet.
+  if (!did_run) {
+    base::RunLoop().Run();
+    EXPECT_TRUE(did_run);
+  }
+}
+
+TEST(AlarmTimerTest, OneShotTimerConcurrentResetAndTimerFired) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_OneShotTimerConcurrentResetAndTimerFired(testing_message_loops[i]);
+  }
+}
+
+TEST(AlarmTimerTest, RepeatingTimerConcurrentResetAndTimerFired) {
+  for (int i = 0; i < kNumTestingMessageLoops; i++) {
+    RunTest_RepeatingTimerConcurrentResetAndTimerFired(
+        testing_message_loops[i]);
+  }
+}
+
+}  // namespace