base/observer_list_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/observer_list.h"
   6 #include "base/observer_list_threadsafe.h"
   7
   8 #include <vector>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/message_loop.h"
  13 #include "base/run_loop.h"
  14 #include "base/threading/platform_thread.h"
  15 #include "testing/gtest/include/gtest/gtest.h"
  16
  17 namespace base {
  18 namespace {
  19
  20 class Foo {
  21  public:
  22   virtual void Observe(int x) = 0;
  23   virtual ~Foo() {}
  24 };
  25
  26 class Adder : public Foo {
  27  public:
  28   explicit Adder(int scaler) : total(0), scaler_(scaler) {}
  29   virtual void Observe(int x) OVERRIDE {
  30     total += x * scaler_;
  31   }
  32   virtual ~Adder() {}
  33   int total;
  34
  35  private:
  36   int scaler_;
  37 };
  38
  39 class Disrupter : public Foo {
  40  public:
  41   Disrupter(ObserverList<Foo>* list, Foo* doomed)
  42       : list_(list),
  43         doomed_(doomed) {
  44   }
  45   virtual ~Disrupter() {}
  46   virtual void Observe(int x) OVERRIDE {
  47     list_->RemoveObserver(doomed_);
  48   }
  49
  50  private:
  51   ObserverList<Foo>* list_;
  52   Foo* doomed_;
  53 };
  54
  55 class ThreadSafeDisrupter : public Foo {
  56  public:
  57   ThreadSafeDisrupter(ObserverListThreadSafe<Foo>* list, Foo* doomed)
  58       : list_(list),
  59         doomed_(doomed) {
  60   }
  61   virtual ~ThreadSafeDisrupter() {}
  62   virtual void Observe(int x) OVERRIDE {
  63     list_->RemoveObserver(doomed_);
  64   }
  65
  66  private:
  67   ObserverListThreadSafe<Foo>* list_;
  68   Foo* doomed_;
  69 };
  70
  71 template <typename ObserverListType>
  72 class AddInObserve : public Foo {
  73  public:
  74   explicit AddInObserve(ObserverListType* observer_list)
  75       : added(false),
  76         observer_list(observer_list),
  77         adder(1) {
  78   }
  79
  80   virtual void Observe(int x) OVERRIDE {
  81     if (!added) {
  82       added = true;
  83       observer_list->AddObserver(&adder);
  84     }
  85   }
  86
  87   bool added;
  88   ObserverListType* observer_list;
  89   Adder adder;
  90 };
  91
  92
  93 static const int kThreadRunTime = 2000;  // ms to run the multi-threaded test.
  94
  95 // A thread for use in the ThreadSafeObserver test
  96 // which will add and remove itself from the notification
  97 // list repeatedly.
  98 class AddRemoveThread : public PlatformThread::Delegate,
  99                         public Foo {
 100  public:
 101   AddRemoveThread(ObserverListThreadSafe<Foo>* list, bool notify)
 102       : list_(list),
 103         loop_(NULL),
 104         in_list_(false),
 105         start_(Time::Now()),
 106         count_observes_(0),
 107         count_addtask_(0),
 108         do_notifies_(notify),
 109         weak_factory_(this) {
 110   }
 111
 112   virtual ~AddRemoveThread() {
 113   }
 114
 115   virtual void ThreadMain() OVERRIDE {
 116     loop_ = new MessageLoop();  // Fire up a message loop.
 117     loop_->PostTask(
 118         FROM_HERE,
 119         base::Bind(&AddRemoveThread::AddTask, weak_factory_.GetWeakPtr()));
 120     loop_->Run();
 121     //LOG(ERROR) << "Loop 0x" << std::hex << loop_ << " done. " <<
 122     //    count_observes_ << ", " << count_addtask_;
 123     delete loop_;
 124     loop_ = reinterpret_cast<MessageLoop*>(0xdeadbeef);
 125     delete this;
 126   }
 127
 128   // This task just keeps posting to itself in an attempt
 129   // to race with the notifier.
 130   void AddTask() {
 131     count_addtask_++;
 132
 133     if ((Time::Now() - start_).InMilliseconds() > kThreadRunTime) {
 134       VLOG(1) << "DONE!";
 135       return;
 136     }
 137
 138     if (!in_list_) {
 139       list_->AddObserver(this);
 140       in_list_ = true;
 141     }
 142
 143     if (do_notifies_) {
 144       list_->Notify(&Foo::Observe, 10);
 145     }
 146
 147     loop_->PostTask(
 148         FROM_HERE,
 149         base::Bind(&AddRemoveThread::AddTask, weak_factory_.GetWeakPtr()));
 150   }
 151
 152   void Quit() {
 153     loop_->PostTask(FROM_HERE, MessageLoop::QuitWhenIdleClosure());
 154   }
 155
 156   virtual void Observe(int x) OVERRIDE {
 157     count_observes_++;
 158
 159     // If we're getting called after we removed ourselves from
 160     // the list, that is very bad!
 161     DCHECK(in_list_);
 162
 163     // This callback should fire on the appropriate thread
 164     EXPECT_EQ(loop_, MessageLoop::current());
 165
 166     list_->RemoveObserver(this);
 167     in_list_ = false;
 168   }
 169
 170  private:
 171   ObserverListThreadSafe<Foo>* list_;
 172   MessageLoop* loop_;
 173   bool in_list_;        // Are we currently registered for notifications.
 174                         // in_list_ is only used on |this| thread.
 175   Time start_;          // The time we started the test.
 176
 177   int count_observes_;  // Number of times we observed.
 178   int count_addtask_;   // Number of times thread AddTask was called
 179   bool do_notifies_;    // Whether these threads should do notifications.
 180
 181   base::WeakPtrFactory<AddRemoveThread> weak_factory_;
 182 };
 183
 184 TEST(ObserverListTest, BasicTest) {
 185   ObserverList<Foo> observer_list;
 186   Adder a(1), b(-1), c(1), d(-1), e(-1);
 187   Disrupter evil(&observer_list, &c);
 188
 189   observer_list.AddObserver(&a);
 190   observer_list.AddObserver(&b);
 191
 192   FOR_EACH_OBSERVER(Foo, observer_list, Observe(10));
 193
 194   observer_list.AddObserver(&evil);
 195   observer_list.AddObserver(&c);
 196   observer_list.AddObserver(&d);
 197
 198   // Removing an observer not in the list should do nothing.
 199   observer_list.RemoveObserver(&e);
 200
 201   FOR_EACH_OBSERVER(Foo, observer_list, Observe(10));
 202
 203   EXPECT_EQ(20, a.total);
 204   EXPECT_EQ(-20, b.total);
 205   EXPECT_EQ(0, c.total);
 206   EXPECT_EQ(-10, d.total);
 207   EXPECT_EQ(0, e.total);
 208 }
 209
 210 TEST(ObserverListThreadSafeTest, BasicTest) {
 211   MessageLoop loop;
 212
 213   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 214       new ObserverListThreadSafe<Foo>);
 215   Adder a(1);
 216   Adder b(-1);
 217   Adder c(1);
 218   Adder d(-1);
 219   ThreadSafeDisrupter evil(observer_list.get(), &c);
 220
 221   observer_list->AddObserver(&a);
 222   observer_list->AddObserver(&b);
 223
 224   observer_list->Notify(&Foo::Observe, 10);
 225   RunLoop().RunUntilIdle();
 226
 227   observer_list->AddObserver(&evil);
 228   observer_list->AddObserver(&c);
 229   observer_list->AddObserver(&d);
 230
 231   observer_list->Notify(&Foo::Observe, 10);
 232   RunLoop().RunUntilIdle();
 233
 234   EXPECT_EQ(20, a.total);
 235   EXPECT_EQ(-20, b.total);
 236   EXPECT_EQ(0, c.total);
 237   EXPECT_EQ(-10, d.total);
 238 }
 239
 240 TEST(ObserverListThreadSafeTest, RemoveObserver) {
 241   MessageLoop loop;
 242
 243   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 244       new ObserverListThreadSafe<Foo>);
 245   Adder a(1), b(1);
 246
 247   // A workaround for the compiler bug. See http://crbug.com/121960.
 248   EXPECT_NE(&a, &b);
 249
 250   // Should do nothing.
 251   observer_list->RemoveObserver(&a);
 252   observer_list->RemoveObserver(&b);
 253
 254   observer_list->Notify(&Foo::Observe, 10);
 255   RunLoop().RunUntilIdle();
 256
 257   EXPECT_EQ(0, a.total);
 258   EXPECT_EQ(0, b.total);
 259
 260   observer_list->AddObserver(&a);
 261
 262   // Should also do nothing.
 263   observer_list->RemoveObserver(&b);
 264
 265   observer_list->Notify(&Foo::Observe, 10);
 266   RunLoop().RunUntilIdle();
 267
 268   EXPECT_EQ(10, a.total);
 269   EXPECT_EQ(0, b.total);
 270 }
 271
 272 TEST(ObserverListThreadSafeTest, WithoutMessageLoop) {
 273   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 274       new ObserverListThreadSafe<Foo>);
 275
 276   Adder a(1), b(1), c(1);
 277
 278   // No MessageLoop, so these should not be added.
 279   observer_list->AddObserver(&a);
 280   observer_list->AddObserver(&b);
 281
 282   {
 283     // Add c when there's a loop.
 284     MessageLoop loop;
 285     observer_list->AddObserver(&c);
 286
 287     observer_list->Notify(&Foo::Observe, 10);
 288     RunLoop().RunUntilIdle();
 289
 290     EXPECT_EQ(0, a.total);
 291     EXPECT_EQ(0, b.total);
 292     EXPECT_EQ(10, c.total);
 293
 294     // Now add a when there's a loop.
 295     observer_list->AddObserver(&a);
 296
 297     // Remove c when there's a loop.
 298     observer_list->RemoveObserver(&c);
 299
 300     // Notify again.
 301     observer_list->Notify(&Foo::Observe, 20);
 302     RunLoop().RunUntilIdle();
 303
 304     EXPECT_EQ(20, a.total);
 305     EXPECT_EQ(0, b.total);
 306     EXPECT_EQ(10, c.total);
 307   }
 308
 309   // Removing should always succeed with or without a loop.
 310   observer_list->RemoveObserver(&a);
 311
 312   // Notifying should not fail but should also be a no-op.
 313   MessageLoop loop;
 314   observer_list->AddObserver(&b);
 315   observer_list->Notify(&Foo::Observe, 30);
 316   RunLoop().RunUntilIdle();
 317
 318   EXPECT_EQ(20, a.total);
 319   EXPECT_EQ(30, b.total);
 320   EXPECT_EQ(10, c.total);
 321 }
 322
 323 class FooRemover : public Foo {
 324  public:
 325   explicit FooRemover(ObserverListThreadSafe<Foo>* list) : list_(list) {}
 326   virtual ~FooRemover() {}
 327
 328   void AddFooToRemove(Foo* foo) {
 329     foos_.push_back(foo);
 330   }
 331
 332   virtual void Observe(int x) OVERRIDE {
 333     std::vector<Foo*> tmp;
 334     tmp.swap(foos_);
 335     for (std::vector<Foo*>::iterator it = tmp.begin();
 336          it != tmp.end(); ++it) {
 337       list_->RemoveObserver(*it);
 338     }
 339   }
 340
 341  private:
 342   const scoped_refptr<ObserverListThreadSafe<Foo> > list_;
 343   std::vector<Foo*> foos_;
 344 };
 345
 346 TEST(ObserverListThreadSafeTest, RemoveMultipleObservers) {
 347   MessageLoop loop;
 348   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 349       new ObserverListThreadSafe<Foo>);
 350
 351   FooRemover a(observer_list.get());
 352   Adder b(1);
 353
 354   observer_list->AddObserver(&a);
 355   observer_list->AddObserver(&b);
 356
 357   a.AddFooToRemove(&a);
 358   a.AddFooToRemove(&b);
 359
 360   observer_list->Notify(&Foo::Observe, 1);
 361   RunLoop().RunUntilIdle();
 362 }
 363
 364 // A test driver for a multi-threaded notification loop.  Runs a number
 365 // of observer threads, each of which constantly adds/removes itself
 366 // from the observer list.  Optionally, if cross_thread_notifies is set
 367 // to true, the observer threads will also trigger notifications to
 368 // all observers.
 369 static void ThreadSafeObserverHarness(int num_threads,
 370                                       bool cross_thread_notifies) {
 371   MessageLoop loop;
 372
 373   const int kMaxThreads = 15;
 374   num_threads = num_threads > kMaxThreads ? kMaxThreads : num_threads;
 375
 376   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 377       new ObserverListThreadSafe<Foo>);
 378   Adder a(1);
 379   Adder b(-1);
 380   Adder c(1);
 381   Adder d(-1);
 382
 383   observer_list->AddObserver(&a);
 384   observer_list->AddObserver(&b);
 385
 386   AddRemoveThread* threaded_observer[kMaxThreads];
 387   base::PlatformThreadHandle threads[kMaxThreads];
 388   for (int index = 0; index < num_threads; index++) {
 389     threaded_observer[index] = new AddRemoveThread(observer_list.get(), false);
 390     EXPECT_TRUE(PlatformThread::Create(0,
 391                 threaded_observer[index], &threads[index]));
 392   }
 393
 394   Time start = Time::Now();
 395   while (true) {
 396     if ((Time::Now() - start).InMilliseconds() > kThreadRunTime)
 397       break;
 398
 399     observer_list->Notify(&Foo::Observe, 10);
 400
 401     RunLoop().RunUntilIdle();
 402   }
 403
 404   for (int index = 0; index < num_threads; index++) {
 405     threaded_observer[index]->Quit();
 406     PlatformThread::Join(threads[index]);
 407   }
 408 }
 409
 410 TEST(ObserverListThreadSafeTest, CrossThreadObserver) {
 411   // Use 7 observer threads.  Notifications only come from
 412   // the main thread.
 413   ThreadSafeObserverHarness(7, false);
 414 }
 415
 416 TEST(ObserverListThreadSafeTest, CrossThreadNotifications) {
 417   // Use 3 observer threads.  Notifications will fire from
 418   // the main thread and all 3 observer threads.
 419   ThreadSafeObserverHarness(3, true);
 420 }
 421
 422 TEST(ObserverListThreadSafeTest, OutlivesMessageLoop) {
 423   MessageLoop* loop = new MessageLoop;
 424   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 425       new ObserverListThreadSafe<Foo>);
 426
 427   Adder a(1);
 428   observer_list->AddObserver(&a);
 429   delete loop;
 430   // Test passes if we don't crash here.
 431   observer_list->Notify(&Foo::Observe, 1);
 432 }
 433
 434 TEST(ObserverListTest, Existing) {
 435   ObserverList<Foo> observer_list(ObserverList<Foo>::NOTIFY_EXISTING_ONLY);
 436   Adder a(1);
 437   AddInObserve<ObserverList<Foo> > b(&observer_list);
 438
 439   observer_list.AddObserver(&a);
 440   observer_list.AddObserver(&b);
 441
 442   FOR_EACH_OBSERVER(Foo, observer_list, Observe(1));
 443
 444   EXPECT_TRUE(b.added);
 445   // B's adder should not have been notified because it was added during
 446   // notificaiton.
 447   EXPECT_EQ(0, b.adder.total);
 448
 449   // Notify again to make sure b's adder is notified.
 450   FOR_EACH_OBSERVER(Foo, observer_list, Observe(1));
 451   EXPECT_EQ(1, b.adder.total);
 452 }
 453
 454 // Same as above, but for ObserverListThreadSafe
 455 TEST(ObserverListThreadSafeTest, Existing) {
 456   MessageLoop loop;
 457   scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
 458       new ObserverListThreadSafe<Foo>(ObserverList<Foo>::NOTIFY_EXISTING_ONLY));
 459   Adder a(1);
 460   AddInObserve<ObserverListThreadSafe<Foo> > b(observer_list.get());
 461
 462   observer_list->AddObserver(&a);
 463   observer_list->AddObserver(&b);
 464
 465   observer_list->Notify(&Foo::Observe, 1);
 466   RunLoop().RunUntilIdle();
 467
 468   EXPECT_TRUE(b.added);
 469   // B's adder should not have been notified because it was added during
 470   // notificaiton.
 471   EXPECT_EQ(0, b.adder.total);
 472
 473   // Notify again to make sure b's adder is notified.
 474   observer_list->Notify(&Foo::Observe, 1);
 475   RunLoop().RunUntilIdle();
 476   EXPECT_EQ(1, b.adder.total);
 477 }
 478
 479 class AddInClearObserve : public Foo {
 480  public:
 481   explicit AddInClearObserve(ObserverList<Foo>* list)
 482       : list_(list), added_(false), adder_(1) {}
 483
 484   virtual void Observe(int /* x */) OVERRIDE {
 485     list_->Clear();
 486     list_->AddObserver(&adder_);
 487     added_ = true;
 488   }
 489
 490   bool added() const { return added_; }
 491   const Adder& adder() const { return adder_; }
 492
 493  private:
 494   ObserverList<Foo>* const list_;
 495
 496   bool added_;
 497   Adder adder_;
 498 };
 499
 500 TEST(ObserverListTest, ClearNotifyAll) {
 501   ObserverList<Foo> observer_list;
 502   AddInClearObserve a(&observer_list);
 503
 504   observer_list.AddObserver(&a);
 505
 506   FOR_EACH_OBSERVER(Foo, observer_list, Observe(1));
 507   EXPECT_TRUE(a.added());
 508   EXPECT_EQ(1, a.adder().total)
 509       << "Adder should observe once and have sum of 1.";
 510 }
 511
 512 TEST(ObserverListTest, ClearNotifyExistingOnly) {
 513   ObserverList<Foo> observer_list(ObserverList<Foo>::NOTIFY_EXISTING_ONLY);
 514   AddInClearObserve a(&observer_list);
 515
 516   observer_list.AddObserver(&a);
 517
 518   FOR_EACH_OBSERVER(Foo, observer_list, Observe(1));
 519   EXPECT_TRUE(a.added());
 520   EXPECT_EQ(0, a.adder().total)
 521       << "Adder should not observe, so sum should still be 0.";
 522 }
 523
 524 class ListDestructor : public Foo {
 525  public:
 526   explicit ListDestructor(ObserverList<Foo>* list) : list_(list) {}
 527   virtual ~ListDestructor() {}
 528
 529   virtual void Observe(int x) OVERRIDE {
 530     delete list_;
 531   }
 532
 533  private:
 534   ObserverList<Foo>* list_;
 535 };
 536
 537
 538 TEST(ObserverListTest, IteratorOutlivesList) {
 539   ObserverList<Foo>* observer_list = new ObserverList<Foo>;
 540   ListDestructor a(observer_list);
 541   observer_list->AddObserver(&a);
 542
 543   FOR_EACH_OBSERVER(Foo, *observer_list, Observe(0));
 544   // If this test fails, there'll be Valgrind errors when this function goes out
 545   // of scope.
 546 }
 547
 548 }  // namespace
 549 }  // namespace base