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