src/base/threading/sequenced_worker_pool_unittest.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/threading/sequenced_worker_pool.h"
   6
   7 #include <algorithm>
   8
   9 #include "base/bind.h"
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/message_loop/message_loop.h"
  14 #include "base/message_loop/message_loop_proxy.h"
  15 #include "base/synchronization/condition_variable.h"
  16 #include "base/synchronization/lock.h"
  17 #include "base/test/sequenced_task_runner_test_template.h"
  18 #include "base/test/sequenced_worker_pool_owner.h"
  19 #include "base/test/task_runner_test_template.h"
  20 #include "base/test/test_timeouts.h"
  21 #include "base/threading/platform_thread.h"
  22 #include "base/time/time.h"
  23 #include "base/tracked_objects.h"
  24 #include "testing/gtest/include/gtest/gtest.h"
  25
  26 namespace base {
  27
  28 // IMPORTANT NOTE:
  29 //
  30 // Many of these tests have failure modes where they'll hang forever. These
  31 // tests should not be flaky, and hanging indicates a type of failure. Do not
  32 // mark as flaky if they're hanging, it's likely an actual bug.
  33
  34 namespace {
  35
  36 const size_t kNumWorkerThreads = 3;
  37
  38 // Allows a number of threads to all be blocked on the same event, and
  39 // provides a way to unblock a certain number of them.
  40 class ThreadBlocker {
  41  public:
  42   ThreadBlocker() : lock_(), cond_var_(&lock_), unblock_counter_(0) {}
  43
  44   void Block() {
  45     {
  46       base::AutoLock lock(lock_);
  47       while (unblock_counter_ == 0)
  48         cond_var_.Wait();
  49       unblock_counter_--;
  50     }
  51     cond_var_.Signal();
  52   }
  53
  54   void Unblock(size_t count) {
  55     {
  56       base::AutoLock lock(lock_);
  57       DCHECK(unblock_counter_ == 0);
  58       unblock_counter_ = count;
  59     }
  60     cond_var_.Signal();
  61   }
  62
  63  private:
  64   base::Lock lock_;
  65   base::ConditionVariable cond_var_;
  66
  67   size_t unblock_counter_;
  68 };
  69
  70 class TestTracker : public base::RefCountedThreadSafe<TestTracker> {
  71  public:
  72   TestTracker()
  73       : lock_(),
  74         cond_var_(&lock_),
  75         started_events_(0) {
  76   }
  77
  78   // Each of these tasks appends the argument to the complete sequence vector
  79   // so calling code can see what order they finished in.
  80   void FastTask(int id) {
  81     SignalWorkerDone(id);
  82   }
  83
  84   void SlowTask(int id) {
  85     base::PlatformThread::Sleep(base::TimeDelta::FromSeconds(1));
  86     SignalWorkerDone(id);
  87   }
  88
  89   void BlockTask(int id, ThreadBlocker* blocker) {
  90     // Note that this task has started and signal anybody waiting for that
  91     // to happen.
  92     {
  93       base::AutoLock lock(lock_);
  94       started_events_++;
  95     }
  96     cond_var_.Signal();
  97
  98     blocker->Block();
  99     SignalWorkerDone(id);
 100   }
 101
 102   void PostAdditionalTasks(
 103         int id, SequencedWorkerPool* pool,
 104         bool expected_return_value) {
 105     Closure fast_task = base::Bind(&TestTracker::FastTask, this, 100);
 106     EXPECT_EQ(expected_return_value,
 107               pool->PostWorkerTaskWithShutdownBehavior(
 108                   FROM_HERE, fast_task,
 109                   SequencedWorkerPool::CONTINUE_ON_SHUTDOWN));
 110     EXPECT_EQ(expected_return_value,
 111               pool->PostWorkerTaskWithShutdownBehavior(
 112                   FROM_HERE, fast_task,
 113                   SequencedWorkerPool::SKIP_ON_SHUTDOWN));
 114     pool->PostWorkerTaskWithShutdownBehavior(
 115         FROM_HERE, fast_task,
 116         SequencedWorkerPool::BLOCK_SHUTDOWN);
 117     SignalWorkerDone(id);
 118   }
 119
 120   // Waits until the given number of tasks have started executing.
 121   void WaitUntilTasksBlocked(size_t count) {
 122     {
 123       base::AutoLock lock(lock_);
 124       while (started_events_ < count)
 125         cond_var_.Wait();
 126     }
 127     cond_var_.Signal();
 128   }
 129
 130   // Blocks the current thread until at least the given number of tasks are in
 131   // the completed vector, and then returns a copy.
 132   std::vector<int> WaitUntilTasksComplete(size_t num_tasks) {
 133     std::vector<int> ret;
 134     {
 135       base::AutoLock lock(lock_);
 136       while (complete_sequence_.size() < num_tasks)
 137         cond_var_.Wait();
 138       ret = complete_sequence_;
 139     }
 140     cond_var_.Signal();
 141     return ret;
 142   }
 143
 144   size_t GetTasksCompletedCount() {
 145     base::AutoLock lock(lock_);
 146     return complete_sequence_.size();
 147   }
 148
 149   void ClearCompleteSequence() {
 150     base::AutoLock lock(lock_);
 151     complete_sequence_.clear();
 152     started_events_ = 0;
 153   }
 154
 155  private:
 156   friend class base::RefCountedThreadSafe<TestTracker>;
 157   ~TestTracker() {}
 158
 159   void SignalWorkerDone(int id) {
 160     {
 161       base::AutoLock lock(lock_);
 162       complete_sequence_.push_back(id);
 163     }
 164     cond_var_.Signal();
 165   }
 166
 167   // Protects the complete_sequence.
 168   base::Lock lock_;
 169
 170   base::ConditionVariable cond_var_;
 171
 172   // Protected by lock_.
 173   std::vector<int> complete_sequence_;
 174
 175   // Counter of the number of "block" workers that have started.
 176   size_t started_events_;
 177 };
 178
 179 class SequencedWorkerPoolTest : public testing::Test {
 180  public:
 181   SequencedWorkerPoolTest()
 182       : tracker_(new TestTracker) {
 183     ResetPool();
 184   }
 185
 186   virtual ~SequencedWorkerPoolTest() {}
 187
 188   virtual void SetUp() override {}
 189
 190   virtual void TearDown() override {
 191     pool()->Shutdown();
 192   }
 193
 194   const scoped_refptr<SequencedWorkerPool>& pool() {
 195     return pool_owner_->pool();
 196   }
 197   TestTracker* tracker() { return tracker_.get(); }
 198
 199   // Destroys the SequencedWorkerPool instance, blocking until it is fully shut
 200   // down, and creates a new instance.
 201   void ResetPool() {
 202     pool_owner_.reset(new SequencedWorkerPoolOwner(kNumWorkerThreads, "test"));
 203   }
 204
 205   void SetWillWaitForShutdownCallback(const Closure& callback) {
 206     pool_owner_->SetWillWaitForShutdownCallback(callback);
 207   }
 208
 209   // Ensures that the given number of worker threads is created by adding
 210   // tasks and waiting until they complete. Worker thread creation is
 211   // serialized, can happen on background threads asynchronously, and doesn't
 212   // happen any more at shutdown. This means that if a test posts a bunch of
 213   // tasks and calls shutdown, fewer workers will be created than the test may
 214   // expect.
 215   //
 216   // This function ensures that this condition can't happen so tests can make
 217   // assumptions about the number of workers active. See the comment in
 218   // PrepareToStartAdditionalThreadIfNecessary in the .cc file for more
 219   // details.
 220   //
 221   // It will post tasks to the queue with id -1. It also assumes this is the
 222   // first thing called in a test since it will clear the complete_sequence_.
 223   void EnsureAllWorkersCreated() {
 224     // Create a bunch of threads, all waiting. This will cause that may
 225     // workers to be created.
 226     ThreadBlocker blocker;
 227     for (size_t i = 0; i < kNumWorkerThreads; i++) {
 228       pool()->PostWorkerTask(FROM_HERE,
 229                              base::Bind(&TestTracker::BlockTask,
 230                                         tracker(), -1, &blocker));
 231     }
 232     tracker()->WaitUntilTasksBlocked(kNumWorkerThreads);
 233
 234     // Now wake them up and wait until they're done.
 235     blocker.Unblock(kNumWorkerThreads);
 236     tracker()->WaitUntilTasksComplete(kNumWorkerThreads);
 237
 238     // Clean up the task IDs we added.
 239     tracker()->ClearCompleteSequence();
 240   }
 241
 242   int has_work_call_count() const {
 243     return pool_owner_->has_work_call_count();
 244   }
 245
 246  private:
 247   MessageLoop message_loop_;
 248   scoped_ptr<SequencedWorkerPoolOwner> pool_owner_;
 249   const scoped_refptr<TestTracker> tracker_;
 250 };
 251
 252 // Checks that the given number of entries are in the tasks to complete of
 253 // the given tracker, and then signals the given event the given number of
 254 // times. This is used to wakt up blocked background threads before blocking
 255 // on shutdown.
 256 void EnsureTasksToCompleteCountAndUnblock(scoped_refptr<TestTracker> tracker,
 257                                           size_t expected_tasks_to_complete,
 258                                           ThreadBlocker* blocker,
 259                                           size_t threads_to_awake) {
 260   EXPECT_EQ(
 261       expected_tasks_to_complete,
 262       tracker->WaitUntilTasksComplete(expected_tasks_to_complete).size());
 263
 264   blocker->Unblock(threads_to_awake);
 265 }
 266
 267 class DeletionHelper : public base::RefCountedThreadSafe<DeletionHelper> {
 268  public:
 269   explicit DeletionHelper(
 270       const scoped_refptr<base::RefCountedData<bool> >& deleted_flag)
 271       : deleted_flag_(deleted_flag) {
 272   }
 273
 274  private:
 275   friend class base::RefCountedThreadSafe<DeletionHelper>;
 276   virtual ~DeletionHelper() { deleted_flag_->data = true; }
 277
 278   const scoped_refptr<base::RefCountedData<bool> > deleted_flag_;
 279   DISALLOW_COPY_AND_ASSIGN(DeletionHelper);
 280 };
 281
 282 void HoldPoolReference(const scoped_refptr<base::SequencedWorkerPool>& pool,
 283                        const scoped_refptr<DeletionHelper>& helper) {
 284   ADD_FAILURE() << "Should never run";
 285 }
 286
 287 // Tests that delayed tasks are deleted upon shutdown of the pool.
 288 TEST_F(SequencedWorkerPoolTest, DelayedTaskDuringShutdown) {
 289   // Post something to verify the pool is started up.
 290   EXPECT_TRUE(pool()->PostTask(
 291       FROM_HERE, base::Bind(&TestTracker::FastTask, tracker(), 1)));
 292
 293   scoped_refptr<base::RefCountedData<bool> > deleted_flag(
 294       new base::RefCountedData<bool>(false));
 295
 296   base::Time posted_at(base::Time::Now());
 297   // Post something that shouldn't run.
 298   EXPECT_TRUE(pool()->PostDelayedTask(
 299       FROM_HERE,
 300       base::Bind(&HoldPoolReference,
 301                  pool(),
 302                  make_scoped_refptr(new DeletionHelper(deleted_flag))),
 303       TestTimeouts::action_timeout()));
 304
 305   std::vector<int> completion_sequence = tracker()->WaitUntilTasksComplete(1);
 306   ASSERT_EQ(1u, completion_sequence.size());
 307   ASSERT_EQ(1, completion_sequence[0]);
 308
 309   pool()->Shutdown();
 310   // Shutdown is asynchronous, so use ResetPool() to block until the pool is
 311   // fully destroyed (and thus shut down).
 312   ResetPool();
 313
 314   // Verify that we didn't block until the task was due.
 315   ASSERT_LT(base::Time::Now() - posted_at, TestTimeouts::action_timeout());
 316
 317   // Verify that the deferred task has not only not run, but has also been
 318   // destroyed.
 319   ASSERT_TRUE(deleted_flag->data);
 320 }
 321
 322 // Tests that same-named tokens have the same ID.
 323 TEST_F(SequencedWorkerPoolTest, NamedTokens) {
 324   const std::string name1("hello");
 325   SequencedWorkerPool::SequenceToken token1 =
 326       pool()->GetNamedSequenceToken(name1);
 327
 328   SequencedWorkerPool::SequenceToken token2 = pool()->GetSequenceToken();
 329
 330   const std::string name3("goodbye");
 331   SequencedWorkerPool::SequenceToken token3 =
 332       pool()->GetNamedSequenceToken(name3);
 333
 334   // All 3 tokens should be different.
 335   EXPECT_FALSE(token1.Equals(token2));
 336   EXPECT_FALSE(token1.Equals(token3));
 337   EXPECT_FALSE(token2.Equals(token3));
 338
 339   // Requesting the same name again should give the same value.
 340   SequencedWorkerPool::SequenceToken token1again =
 341       pool()->GetNamedSequenceToken(name1);
 342   EXPECT_TRUE(token1.Equals(token1again));
 343
 344   SequencedWorkerPool::SequenceToken token3again =
 345       pool()->GetNamedSequenceToken(name3);
 346   EXPECT_TRUE(token3.Equals(token3again));
 347 }
 348
 349 // Tests that posting a bunch of tasks (many more than the number of worker
 350 // threads) runs them all.
 351 TEST_F(SequencedWorkerPoolTest, LotsOfTasks) {
 352   pool()->PostWorkerTask(FROM_HERE,
 353                          base::Bind(&TestTracker::SlowTask, tracker(), 0));
 354
 355   const size_t kNumTasks = 20;
 356   for (size_t i = 1; i < kNumTasks; i++) {
 357     pool()->PostWorkerTask(FROM_HERE,
 358                            base::Bind(&TestTracker::FastTask, tracker(), i));
 359   }
 360
 361   std::vector<int> result = tracker()->WaitUntilTasksComplete(kNumTasks);
 362   EXPECT_EQ(kNumTasks, result.size());
 363 }
 364
 365 // Tests that posting a bunch of tasks (many more than the number of
 366 // worker threads) to two pools simultaneously runs them all twice.
 367 // This test is meant to shake out any concurrency issues between
 368 // pools (like histograms).
 369 TEST_F(SequencedWorkerPoolTest, LotsOfTasksTwoPools) {
 370   SequencedWorkerPoolOwner pool1(kNumWorkerThreads, "test1");
 371   SequencedWorkerPoolOwner pool2(kNumWorkerThreads, "test2");
 372
 373   base::Closure slow_task = base::Bind(&TestTracker::SlowTask, tracker(), 0);
 374   pool1.pool()->PostWorkerTask(FROM_HERE, slow_task);
 375   pool2.pool()->PostWorkerTask(FROM_HERE, slow_task);
 376
 377   const size_t kNumTasks = 20;
 378   for (size_t i = 1; i < kNumTasks; i++) {
 379     base::Closure fast_task =
 380         base::Bind(&TestTracker::FastTask, tracker(), i);
 381     pool1.pool()->PostWorkerTask(FROM_HERE, fast_task);
 382     pool2.pool()->PostWorkerTask(FROM_HERE, fast_task);
 383   }
 384
 385   std::vector<int> result =
 386       tracker()->WaitUntilTasksComplete(2*kNumTasks);
 387   EXPECT_EQ(2 * kNumTasks, result.size());
 388
 389   pool2.pool()->Shutdown();
 390   pool1.pool()->Shutdown();
 391 }
 392
 393 // Test that tasks with the same sequence token are executed in order but don't
 394 // affect other tasks.
 395 TEST_F(SequencedWorkerPoolTest, Sequence) {
 396   // Fill all the worker threads except one.
 397   const size_t kNumBackgroundTasks = kNumWorkerThreads - 1;
 398   ThreadBlocker background_blocker;
 399   for (size_t i = 0; i < kNumBackgroundTasks; i++) {
 400     pool()->PostWorkerTask(FROM_HERE,
 401                            base::Bind(&TestTracker::BlockTask,
 402                                       tracker(), i, &background_blocker));
 403   }
 404   tracker()->WaitUntilTasksBlocked(kNumBackgroundTasks);
 405
 406   // Create two tasks with the same sequence token, one that will block on the
 407   // event, and one which will just complete quickly when it's run. Since there
 408   // is one worker thread free, the first task will start and then block, and
 409   // the second task should be waiting.
 410   ThreadBlocker blocker;
 411   SequencedWorkerPool::SequenceToken token1 = pool()->GetSequenceToken();
 412   pool()->PostSequencedWorkerTask(
 413       token1, FROM_HERE,
 414       base::Bind(&TestTracker::BlockTask, tracker(), 100, &blocker));
 415   pool()->PostSequencedWorkerTask(
 416       token1, FROM_HERE,
 417       base::Bind(&TestTracker::FastTask, tracker(), 101));
 418   EXPECT_EQ(0u, tracker()->WaitUntilTasksComplete(0).size());
 419
 420   // Create another two tasks as above with a different token. These will be
 421   // blocked since there are no slots to run.
 422   SequencedWorkerPool::SequenceToken token2 = pool()->GetSequenceToken();
 423   pool()->PostSequencedWorkerTask(
 424       token2, FROM_HERE,
 425       base::Bind(&TestTracker::FastTask, tracker(), 200));
 426   pool()->PostSequencedWorkerTask(
 427       token2, FROM_HERE,
 428       base::Bind(&TestTracker::FastTask, tracker(), 201));
 429   EXPECT_EQ(0u, tracker()->WaitUntilTasksComplete(0).size());
 430
 431   // Let one background task complete. This should then let both tasks of
 432   // token2 run to completion in order. The second task of token1 should still
 433   // be blocked.
 434   background_blocker.Unblock(1);
 435   std::vector<int> result = tracker()->WaitUntilTasksComplete(3);
 436   ASSERT_EQ(3u, result.size());
 437   EXPECT_EQ(200, result[1]);
 438   EXPECT_EQ(201, result[2]);
 439
 440   // Finish the rest of the background tasks. This should leave some workers
 441   // free with the second token1 task still blocked on the first.
 442   background_blocker.Unblock(kNumBackgroundTasks - 1);
 443   EXPECT_EQ(kNumBackgroundTasks + 2,
 444             tracker()->WaitUntilTasksComplete(kNumBackgroundTasks + 2).size());
 445
 446   // Allow the first task of token1 to complete. This should run the second.
 447   blocker.Unblock(1);
 448   result = tracker()->WaitUntilTasksComplete(kNumBackgroundTasks + 4);
 449   ASSERT_EQ(kNumBackgroundTasks + 4, result.size());
 450   EXPECT_EQ(100, result[result.size() - 2]);
 451   EXPECT_EQ(101, result[result.size() - 1]);
 452 }
 453
 454 // Tests that any tasks posted after Shutdown are ignored.
 455 // Disabled for flakiness.  See http://crbug.com/166451.
 456 TEST_F(SequencedWorkerPoolTest, DISABLED_IgnoresAfterShutdown) {
 457   // Start tasks to take all the threads and block them.
 458   EnsureAllWorkersCreated();
 459   ThreadBlocker blocker;
 460   for (size_t i = 0; i < kNumWorkerThreads; i++) {
 461     pool()->PostWorkerTask(FROM_HERE,
 462                            base::Bind(&TestTracker::BlockTask,
 463                                       tracker(), i, &blocker));
 464   }
 465   tracker()->WaitUntilTasksBlocked(kNumWorkerThreads);
 466
 467   SetWillWaitForShutdownCallback(
 468       base::Bind(&EnsureTasksToCompleteCountAndUnblock,
 469                  scoped_refptr<TestTracker>(tracker()), 0,
 470                  &blocker, kNumWorkerThreads));
 471
 472   // Shutdown the worker pool. This should discard all non-blocking tasks.
 473   const int kMaxNewBlockingTasksAfterShutdown = 100;
 474   pool()->Shutdown(kMaxNewBlockingTasksAfterShutdown);
 475
 476   int old_has_work_call_count = has_work_call_count();
 477
 478   std::vector<int> result =
 479       tracker()->WaitUntilTasksComplete(kNumWorkerThreads);
 480
 481   // The kNumWorkerThread items should have completed, in no particular order.
 482   ASSERT_EQ(kNumWorkerThreads, result.size());
 483   for (size_t i = 0; i < kNumWorkerThreads; i++) {
 484     EXPECT_TRUE(std::find(result.begin(), result.end(), static_cast<int>(i)) !=
 485                 result.end());
 486   }
 487
 488   // No further tasks, regardless of shutdown mode, should be allowed.
 489   EXPECT_FALSE(pool()->PostWorkerTaskWithShutdownBehavior(
 490       FROM_HERE,
 491       base::Bind(&TestTracker::FastTask, tracker(), 100),
 492       SequencedWorkerPool::CONTINUE_ON_SHUTDOWN));
 493   EXPECT_FALSE(pool()->PostWorkerTaskWithShutdownBehavior(
 494       FROM_HERE,
 495       base::Bind(&TestTracker::FastTask, tracker(), 101),
 496       SequencedWorkerPool::SKIP_ON_SHUTDOWN));
 497   EXPECT_FALSE(pool()->PostWorkerTaskWithShutdownBehavior(
 498       FROM_HERE,
 499       base::Bind(&TestTracker::FastTask, tracker(), 102),
 500       SequencedWorkerPool::BLOCK_SHUTDOWN));
 501
 502   ASSERT_EQ(old_has_work_call_count, has_work_call_count());
 503 }
 504
 505 TEST_F(SequencedWorkerPoolTest, AllowsAfterShutdown) {
 506   // Test that <n> new blocking tasks are allowed provided they're posted
 507   // by a running tasks.
 508   EnsureAllWorkersCreated();
 509   ThreadBlocker blocker;
 510
 511   // Start tasks to take all the threads and block them.
 512   const int kNumBlockTasks = static_cast<int>(kNumWorkerThreads);
 513   for (int i = 0; i < kNumBlockTasks; ++i) {
 514     EXPECT_TRUE(pool()->PostWorkerTask(
 515         FROM_HERE,
 516         base::Bind(&TestTracker::BlockTask, tracker(), i, &blocker)));
 517   }
 518   tracker()->WaitUntilTasksBlocked(kNumWorkerThreads);
 519
 520   // Queue up shutdown blocking tasks behind those which will attempt to post
 521   // additional tasks when run, PostAdditionalTasks attemtps to post 3
 522   // new FastTasks, one for each shutdown_behavior.
 523   const int kNumQueuedTasks = static_cast<int>(kNumWorkerThreads);
 524   for (int i = 0; i < kNumQueuedTasks; ++i) {
 525     EXPECT_TRUE(pool()->PostWorkerTaskWithShutdownBehavior(
 526         FROM_HERE,
 527         base::Bind(&TestTracker::PostAdditionalTasks, tracker(), i, pool(),
 528                    false),
 529         SequencedWorkerPool::BLOCK_SHUTDOWN));
 530   }
 531
 532   // Setup to open the floodgates from within Shutdown().
 533   SetWillWaitForShutdownCallback(
 534       base::Bind(&EnsureTasksToCompleteCountAndUnblock,
 535                  scoped_refptr<TestTracker>(tracker()),
 536                  0, &blocker, kNumBlockTasks));
 537
 538   // Allow half of the additional blocking tasks thru.
 539   const int kNumNewBlockingTasksToAllow = kNumWorkerThreads / 2;
 540   pool()->Shutdown(kNumNewBlockingTasksToAllow);
 541
 542   // Ensure that the correct number of tasks actually got run.
 543   tracker()->WaitUntilTasksComplete(static_cast<size_t>(
 544       kNumBlockTasks + kNumQueuedTasks + kNumNewBlockingTasksToAllow));
 545
 546   // Clean up the task IDs we added and go home.
 547   tracker()->ClearCompleteSequence();
 548 }
 549
 550 // Tests that unrun tasks are discarded properly according to their shutdown
 551 // mode.
 552 TEST_F(SequencedWorkerPoolTest, DiscardOnShutdown) {
 553   // Start tasks to take all the threads and block them.
 554   EnsureAllWorkersCreated();
 555   ThreadBlocker blocker;
 556   for (size_t i = 0; i < kNumWorkerThreads; i++) {
 557     pool()->PostWorkerTask(FROM_HERE,
 558                            base::Bind(&TestTracker::BlockTask,
 559                                       tracker(), i, &blocker));
 560   }
 561   tracker()->WaitUntilTasksBlocked(kNumWorkerThreads);
 562
 563   // Create some tasks with different shutdown modes.
 564   pool()->PostWorkerTaskWithShutdownBehavior(
 565       FROM_HERE,
 566       base::Bind(&TestTracker::FastTask, tracker(), 100),
 567       SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 568   pool()->PostWorkerTaskWithShutdownBehavior(
 569       FROM_HERE,
 570       base::Bind(&TestTracker::FastTask, tracker(), 101),
 571       SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 572   pool()->PostWorkerTaskWithShutdownBehavior(
 573       FROM_HERE,
 574       base::Bind(&TestTracker::FastTask, tracker(), 102),
 575       SequencedWorkerPool::BLOCK_SHUTDOWN);
 576
 577   // Shutdown the worker pool. This should discard all non-blocking tasks.
 578   SetWillWaitForShutdownCallback(
 579       base::Bind(&EnsureTasksToCompleteCountAndUnblock,
 580                  scoped_refptr<TestTracker>(tracker()), 0,
 581                  &blocker, kNumWorkerThreads));
 582   pool()->Shutdown();
 583
 584   std::vector<int> result =
 585       tracker()->WaitUntilTasksComplete(kNumWorkerThreads + 1);
 586
 587   // The kNumWorkerThread items should have completed, plus the BLOCK_SHUTDOWN
 588   // one, in no particular order.
 589   ASSERT_EQ(kNumWorkerThreads + 1, result.size());
 590   for (size_t i = 0; i < kNumWorkerThreads; i++) {
 591     EXPECT_TRUE(std::find(result.begin(), result.end(), static_cast<int>(i)) !=
 592                 result.end());
 593   }
 594   EXPECT_TRUE(std::find(result.begin(), result.end(), 102) != result.end());
 595 }
 596
 597 // Tests that CONTINUE_ON_SHUTDOWN tasks don't block shutdown.
 598 TEST_F(SequencedWorkerPoolTest, ContinueOnShutdown) {
 599   scoped_refptr<TaskRunner> runner(pool()->GetTaskRunnerWithShutdownBehavior(
 600       SequencedWorkerPool::CONTINUE_ON_SHUTDOWN));
 601   scoped_refptr<SequencedTaskRunner> sequenced_runner(
 602       pool()->GetSequencedTaskRunnerWithShutdownBehavior(
 603           pool()->GetSequenceToken(),
 604           SequencedWorkerPool::CONTINUE_ON_SHUTDOWN));
 605   EnsureAllWorkersCreated();
 606   ThreadBlocker blocker;
 607   pool()->PostWorkerTaskWithShutdownBehavior(
 608       FROM_HERE,
 609       base::Bind(&TestTracker::BlockTask,
 610                  tracker(), 0, &blocker),
 611       SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 612   runner->PostTask(
 613       FROM_HERE,
 614       base::Bind(&TestTracker::BlockTask,
 615                  tracker(), 1, &blocker));
 616   sequenced_runner->PostTask(
 617       FROM_HERE,
 618       base::Bind(&TestTracker::BlockTask,
 619                  tracker(), 2, &blocker));
 620
 621   tracker()->WaitUntilTasksBlocked(3);
 622
 623   // This should not block. If this test hangs, it means it failed.
 624   pool()->Shutdown();
 625
 626   // The task should not have completed yet.
 627   EXPECT_EQ(0u, tracker()->WaitUntilTasksComplete(0).size());
 628
 629   // Posting more tasks should fail.
 630   EXPECT_FALSE(pool()->PostWorkerTaskWithShutdownBehavior(
 631       FROM_HERE, base::Bind(&TestTracker::FastTask, tracker(), 0),
 632       SequencedWorkerPool::CONTINUE_ON_SHUTDOWN));
 633   EXPECT_FALSE(runner->PostTask(
 634       FROM_HERE, base::Bind(&TestTracker::FastTask, tracker(), 0)));
 635   EXPECT_FALSE(sequenced_runner->PostTask(
 636       FROM_HERE, base::Bind(&TestTracker::FastTask, tracker(), 0)));
 637
 638   // Continue the background thread and make sure the tasks can complete.
 639   blocker.Unblock(3);
 640   std::vector<int> result = tracker()->WaitUntilTasksComplete(3);
 641   EXPECT_EQ(3u, result.size());
 642 }
 643
 644 // Tests that SKIP_ON_SHUTDOWN tasks that have been started block Shutdown
 645 // until they stop, but tasks not yet started do not.
 646 TEST_F(SequencedWorkerPoolTest, SkipOnShutdown) {
 647   // Start tasks to take all the threads and block them.
 648   EnsureAllWorkersCreated();
 649   ThreadBlocker blocker;
 650
 651   // Now block all the threads with SKIP_ON_SHUTDOWN. Shutdown() should not
 652   // return until these tasks have completed.
 653   for (size_t i = 0; i < kNumWorkerThreads; i++) {
 654     pool()->PostWorkerTaskWithShutdownBehavior(
 655         FROM_HERE,
 656         base::Bind(&TestTracker::BlockTask, tracker(), i, &blocker),
 657         SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 658   }
 659   tracker()->WaitUntilTasksBlocked(kNumWorkerThreads);
 660
 661   // Now post an additional task as SKIP_ON_SHUTDOWN, which should not be
 662   // executed once Shutdown() has been called.
 663   pool()->PostWorkerTaskWithShutdownBehavior(
 664       FROM_HERE,
 665       base::Bind(&TestTracker::BlockTask,
 666                  tracker(), 0, &blocker),
 667       SequencedWorkerPool::SKIP_ON_SHUTDOWN);
 668
 669   // This callback will only be invoked if SKIP_ON_SHUTDOWN tasks that have
 670   // been started block shutdown.
 671   SetWillWaitForShutdownCallback(
 672       base::Bind(&EnsureTasksToCompleteCountAndUnblock,
 673                  scoped_refptr<TestTracker>(tracker()), 0,
 674                  &blocker, kNumWorkerThreads));
 675
 676   // No tasks should have completed yet.
 677   EXPECT_EQ(0u, tracker()->WaitUntilTasksComplete(0).size());
 678
 679   // This should not block. If this test hangs, it means it failed.
 680   pool()->Shutdown();
 681
 682   // Shutdown should not return until all of the tasks have completed.
 683   std::vector<int> result =
 684       tracker()->WaitUntilTasksComplete(kNumWorkerThreads);
 685
 686   // Only tasks marked SKIP_ON_SHUTDOWN that were already started should be
 687   // allowed to complete. No additional non-blocking tasks should have been
 688   // started.
 689   ASSERT_EQ(kNumWorkerThreads, result.size());
 690   for (size_t i = 0; i < kNumWorkerThreads; i++) {
 691     EXPECT_TRUE(std::find(result.begin(), result.end(), static_cast<int>(i)) !=
 692                 result.end());
 693   }
 694 }
 695
 696 // Ensure all worker threads are created, and then trigger a spurious
 697 // work signal. This shouldn't cause any other work signals to be
 698 // triggered. This is a regression test for http://crbug.com/117469.
 699 TEST_F(SequencedWorkerPoolTest, SpuriousWorkSignal) {
 700   EnsureAllWorkersCreated();
 701   int old_has_work_call_count = has_work_call_count();
 702   pool()->SignalHasWorkForTesting();
 703   // This is inherently racy, but can only produce false positives.
 704   base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100));
 705   EXPECT_EQ(old_has_work_call_count + 1, has_work_call_count());
 706 }
 707
 708 void IsRunningOnCurrentThreadTask(
 709     SequencedWorkerPool::SequenceToken test_positive_token,
 710     SequencedWorkerPool::SequenceToken test_negative_token,
 711     SequencedWorkerPool* pool,
 712     SequencedWorkerPool* unused_pool) {
 713   EXPECT_TRUE(pool->RunsTasksOnCurrentThread());
 714   EXPECT_TRUE(pool->IsRunningSequenceOnCurrentThread(test_positive_token));
 715   EXPECT_FALSE(pool->IsRunningSequenceOnCurrentThread(test_negative_token));
 716   EXPECT_FALSE(unused_pool->RunsTasksOnCurrentThread());
 717   EXPECT_FALSE(
 718       unused_pool->IsRunningSequenceOnCurrentThread(test_positive_token));
 719   EXPECT_FALSE(
 720       unused_pool->IsRunningSequenceOnCurrentThread(test_negative_token));
 721 }
 722
 723 // Verify correctness of the IsRunningSequenceOnCurrentThread method.
 724 TEST_F(SequencedWorkerPoolTest, IsRunningOnCurrentThread) {
 725   SequencedWorkerPool::SequenceToken token1 = pool()->GetSequenceToken();
 726   SequencedWorkerPool::SequenceToken token2 = pool()->GetSequenceToken();
 727   SequencedWorkerPool::SequenceToken unsequenced_token;
 728
 729   scoped_refptr<SequencedWorkerPool> unused_pool =
 730       new SequencedWorkerPool(2, "unused_pool");
 731
 732   EXPECT_FALSE(pool()->RunsTasksOnCurrentThread());
 733   EXPECT_FALSE(pool()->IsRunningSequenceOnCurrentThread(token1));
 734   EXPECT_FALSE(pool()->IsRunningSequenceOnCurrentThread(token2));
 735   EXPECT_FALSE(pool()->IsRunningSequenceOnCurrentThread(unsequenced_token));
 736   EXPECT_FALSE(unused_pool->RunsTasksOnCurrentThread());
 737   EXPECT_FALSE(unused_pool->IsRunningSequenceOnCurrentThread(token1));
 738   EXPECT_FALSE(unused_pool->IsRunningSequenceOnCurrentThread(token2));
 739   EXPECT_FALSE(
 740       unused_pool->IsRunningSequenceOnCurrentThread(unsequenced_token));
 741
 742   pool()->PostSequencedWorkerTask(
 743       token1, FROM_HERE,
 744       base::Bind(&IsRunningOnCurrentThreadTask,
 745                  token1, token2, pool(), unused_pool));
 746   pool()->PostSequencedWorkerTask(
 747       token2, FROM_HERE,
 748       base::Bind(&IsRunningOnCurrentThreadTask,
 749                  token2, unsequenced_token, pool(), unused_pool));
 750   pool()->PostWorkerTask(
 751       FROM_HERE,
 752       base::Bind(&IsRunningOnCurrentThreadTask,
 753                  unsequenced_token, token1, pool(), unused_pool));
 754   pool()->Shutdown();
 755   unused_pool->Shutdown();
 756 }
 757
 758 // Verify that FlushForTesting works as intended.
 759 TEST_F(SequencedWorkerPoolTest, FlushForTesting) {
 760   // Should be fine to call on a new instance.
 761   pool()->FlushForTesting();
 762
 763   // Queue up a bunch of work, including  a long delayed task and
 764   // a task that produces additional tasks as an artifact.
 765   pool()->PostDelayedWorkerTask(
 766       FROM_HERE,
 767       base::Bind(&TestTracker::FastTask, tracker(), 0),
 768       TimeDelta::FromMinutes(5));
 769   pool()->PostWorkerTask(FROM_HERE,
 770                          base::Bind(&TestTracker::SlowTask, tracker(), 0));
 771   const size_t kNumFastTasks = 20;
 772   for (size_t i = 0; i < kNumFastTasks; i++) {
 773     pool()->PostWorkerTask(FROM_HERE,
 774                            base::Bind(&TestTracker::FastTask, tracker(), 0));
 775   }
 776   pool()->PostWorkerTask(
 777       FROM_HERE,
 778       base::Bind(&TestTracker::PostAdditionalTasks, tracker(), 0, pool(),
 779                  true));
 780
 781   // We expect all except the delayed task to have been run. We verify all
 782   // closures have been deleted by looking at the refcount of the
 783   // tracker.
 784   EXPECT_FALSE(tracker()->HasOneRef());
 785   pool()->FlushForTesting();
 786   EXPECT_TRUE(tracker()->HasOneRef());
 787   EXPECT_EQ(1 + kNumFastTasks + 1 + 3, tracker()->GetTasksCompletedCount());
 788
 789   // Should be fine to call on an idle instance with all threads created, and
 790   // spamming the method shouldn't deadlock or confuse the class.
 791   pool()->FlushForTesting();
 792   pool()->FlushForTesting();
 793
 794   // Should be fine to call after shutdown too.
 795   pool()->Shutdown();
 796   pool()->FlushForTesting();
 797 }
 798
 799 TEST(SequencedWorkerPoolRefPtrTest, ShutsDownCleanWithContinueOnShutdown) {
 800   MessageLoop loop;
 801   scoped_refptr<SequencedWorkerPool> pool(new SequencedWorkerPool(3, "Pool"));
 802   scoped_refptr<SequencedTaskRunner> task_runner =
 803       pool->GetSequencedTaskRunnerWithShutdownBehavior(
 804           pool->GetSequenceToken(),
 805           base::SequencedWorkerPool::CONTINUE_ON_SHUTDOWN);
 806
 807   // Upon test exit, should shut down without hanging.
 808   pool->Shutdown();
 809 }
 810
 811 class SequencedWorkerPoolTaskRunnerTestDelegate {
 812  public:
 813   SequencedWorkerPoolTaskRunnerTestDelegate() {}
 814
 815   ~SequencedWorkerPoolTaskRunnerTestDelegate() {}
 816
 817   void StartTaskRunner() {
 818     pool_owner_.reset(
 819         new SequencedWorkerPoolOwner(10, "SequencedWorkerPoolTaskRunnerTest"));
 820   }
 821
 822   scoped_refptr<SequencedWorkerPool> GetTaskRunner() {
 823     return pool_owner_->pool();
 824   }
 825
 826   void StopTaskRunner() {
 827     // Make sure all tasks are run before shutting down. Delayed tasks are
 828     // not run, they're simply deleted.
 829     pool_owner_->pool()->FlushForTesting();
 830     pool_owner_->pool()->Shutdown();
 831     // Don't reset |pool_owner_| here, as the test may still hold a
 832     // reference to the pool.
 833   }
 834
 835  private:
 836   MessageLoop message_loop_;
 837   scoped_ptr<SequencedWorkerPoolOwner> pool_owner_;
 838 };
 839
 840 INSTANTIATE_TYPED_TEST_CASE_P(
 841     SequencedWorkerPool, TaskRunnerTest,
 842     SequencedWorkerPoolTaskRunnerTestDelegate);
 843
 844 class SequencedWorkerPoolTaskRunnerWithShutdownBehaviorTestDelegate {
 845  public:
 846   SequencedWorkerPoolTaskRunnerWithShutdownBehaviorTestDelegate() {}
 847
 848   ~SequencedWorkerPoolTaskRunnerWithShutdownBehaviorTestDelegate() {
 849   }
 850
 851   void StartTaskRunner() {
 852     pool_owner_.reset(
 853         new SequencedWorkerPoolOwner(10, "SequencedWorkerPoolTaskRunnerTest"));
 854     task_runner_ = pool_owner_->pool()->GetTaskRunnerWithShutdownBehavior(
 855         SequencedWorkerPool::BLOCK_SHUTDOWN);
 856   }
 857
 858   scoped_refptr<TaskRunner> GetTaskRunner() {
 859     return task_runner_;
 860   }
 861
 862   void StopTaskRunner() {
 863     // Make sure all tasks are run before shutting down. Delayed tasks are
 864     // not run, they're simply deleted.
 865     pool_owner_->pool()->FlushForTesting();
 866     pool_owner_->pool()->Shutdown();
 867     // Don't reset |pool_owner_| here, as the test may still hold a
 868     // reference to the pool.
 869   }
 870
 871  private:
 872   MessageLoop message_loop_;
 873   scoped_ptr<SequencedWorkerPoolOwner> pool_owner_;
 874   scoped_refptr<TaskRunner> task_runner_;
 875 };
 876
 877 INSTANTIATE_TYPED_TEST_CASE_P(
 878     SequencedWorkerPoolTaskRunner, TaskRunnerTest,
 879     SequencedWorkerPoolTaskRunnerWithShutdownBehaviorTestDelegate);
 880
 881 class SequencedWorkerPoolSequencedTaskRunnerTestDelegate {
 882  public:
 883   SequencedWorkerPoolSequencedTaskRunnerTestDelegate() {}
 884
 885   ~SequencedWorkerPoolSequencedTaskRunnerTestDelegate() {
 886   }
 887
 888   void StartTaskRunner() {
 889     pool_owner_.reset(new SequencedWorkerPoolOwner(
 890         10, "SequencedWorkerPoolSequencedTaskRunnerTest"));
 891     task_runner_ = pool_owner_->pool()->GetSequencedTaskRunner(
 892         pool_owner_->pool()->GetSequenceToken());
 893   }
 894
 895   scoped_refptr<SequencedTaskRunner> GetTaskRunner() {
 896     return task_runner_;
 897   }
 898
 899   void StopTaskRunner() {
 900     // Make sure all tasks are run before shutting down. Delayed tasks are
 901     // not run, they're simply deleted.
 902     pool_owner_->pool()->FlushForTesting();
 903     pool_owner_->pool()->Shutdown();
 904     // Don't reset |pool_owner_| here, as the test may still hold a
 905     // reference to the pool.
 906   }
 907
 908  private:
 909   MessageLoop message_loop_;
 910   scoped_ptr<SequencedWorkerPoolOwner> pool_owner_;
 911   scoped_refptr<SequencedTaskRunner> task_runner_;
 912 };
 913
 914 INSTANTIATE_TYPED_TEST_CASE_P(
 915     SequencedWorkerPoolSequencedTaskRunner, TaskRunnerTest,
 916     SequencedWorkerPoolSequencedTaskRunnerTestDelegate);
 917
 918 INSTANTIATE_TYPED_TEST_CASE_P(
 919     SequencedWorkerPoolSequencedTaskRunner, SequencedTaskRunnerTest,
 920     SequencedWorkerPoolSequencedTaskRunnerTestDelegate);
 921
 922 }  // namespace
 923
 924 }  // namespace base