src/base/memory/weak_ptr_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/memory/weak_ptr.h"
   6
   7 #include <string>
   8
   9 #include "base/bind.h"
  10 #include "base/debug/leak_annotations.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/message_loop/message_loop.h"
  13 #include "base/synchronization/waitable_event.h"
  14 #include "base/threading/thread.h"
  15 #include "testing/gtest/include/gtest/gtest.h"
  16
  17 namespace base {
  18 namespace {
  19
  20 template <class T>
  21 class OffThreadObjectCreator {
  22  public:
  23   static T* NewObject() {
  24     T* result;
  25     {
  26       Thread creator_thread("creator_thread");
  27       creator_thread.Start();
  28       creator_thread.message_loop()->PostTask(
  29           FROM_HERE,
  30           base::Bind(OffThreadObjectCreator::CreateObject, &result));
  31     }
  32     DCHECK(result);  // We synchronized on thread destruction above.
  33     return result;
  34   }
  35  private:
  36   static void CreateObject(T** result) {
  37     *result = new T;
  38   }
  39 };
  40
  41 struct Base {
  42   std::string member;
  43 };
  44 struct Derived : public Base {};
  45
  46 struct TargetBase {};
  47 struct Target : public TargetBase, public SupportsWeakPtr<Target> {
  48   virtual ~Target() {}
  49 };
  50 struct DerivedTarget : public Target {};
  51 struct Arrow {
  52   WeakPtr<Target> target;
  53 };
  54 struct TargetWithFactory : public Target {
  55   TargetWithFactory() : factory(this) {}
  56   WeakPtrFactory<Target> factory;
  57 };
  58
  59 // Helper class to create and destroy weak pointer copies
  60 // and delete objects on a background thread.
  61 class BackgroundThread : public Thread {
  62  public:
  63   BackgroundThread() : Thread("owner_thread") {}
  64
  65   virtual ~BackgroundThread() {
  66     Stop();
  67   }
  68
  69   void CreateArrowFromTarget(Arrow** arrow, Target* target) {
  70     WaitableEvent completion(true, false);
  71     message_loop()->PostTask(
  72         FROM_HERE,
  73         base::Bind(&BackgroundThread::DoCreateArrowFromTarget,
  74                    arrow, target, &completion));
  75     completion.Wait();
  76   }
  77
  78   void CreateArrowFromArrow(Arrow** arrow, const Arrow* other) {
  79     WaitableEvent completion(true, false);
  80     message_loop()->PostTask(
  81         FROM_HERE,
  82         base::Bind(&BackgroundThread::DoCreateArrowFromArrow,
  83                    arrow, other, &completion));
  84     completion.Wait();
  85   }
  86
  87   void DeleteTarget(Target* object) {
  88     WaitableEvent completion(true, false);
  89     message_loop()->PostTask(
  90         FROM_HERE,
  91         base::Bind(&BackgroundThread::DoDeleteTarget, object, &completion));
  92     completion.Wait();
  93   }
  94
  95   void CopyAndAssignArrow(Arrow* object) {
  96     WaitableEvent completion(true, false);
  97     message_loop()->PostTask(
  98         FROM_HERE,
  99         base::Bind(&BackgroundThread::DoCopyAndAssignArrow,
 100                    object, &completion));
 101     completion.Wait();
 102   }
 103
 104   void CopyAndAssignArrowBase(Arrow* object) {
 105     WaitableEvent completion(true, false);
 106     message_loop()->PostTask(
 107         FROM_HERE,
 108         base::Bind(&BackgroundThread::DoCopyAndAssignArrowBase,
 109                    object, &completion));
 110     completion.Wait();
 111   }
 112
 113   void DeleteArrow(Arrow* object) {
 114     WaitableEvent completion(true, false);
 115     message_loop()->PostTask(
 116         FROM_HERE,
 117         base::Bind(&BackgroundThread::DoDeleteArrow, object, &completion));
 118     completion.Wait();
 119   }
 120
 121   Target* DeRef(const Arrow* arrow) {
 122     WaitableEvent completion(true, false);
 123     Target* result = NULL;
 124     message_loop()->PostTask(
 125         FROM_HERE,
 126         base::Bind(&BackgroundThread::DoDeRef, arrow, &result, &completion));
 127     completion.Wait();
 128     return result;
 129   }
 130
 131  protected:
 132   static void DoCreateArrowFromArrow(Arrow** arrow,
 133                                      const Arrow* other,
 134                                      WaitableEvent* completion) {
 135     *arrow = new Arrow;
 136     **arrow = *other;
 137     completion->Signal();
 138   }
 139
 140   static void DoCreateArrowFromTarget(Arrow** arrow,
 141                                       Target* target,
 142                                       WaitableEvent* completion) {
 143     *arrow = new Arrow;
 144     (*arrow)->target = target->AsWeakPtr();
 145     completion->Signal();
 146   }
 147
 148   static void DoDeRef(const Arrow* arrow,
 149                       Target** result,
 150                       WaitableEvent* completion) {
 151     *result = arrow->target.get();
 152     completion->Signal();
 153   }
 154
 155   static void DoDeleteTarget(Target* object, WaitableEvent* completion) {
 156     delete object;
 157     completion->Signal();
 158   }
 159
 160   static void DoCopyAndAssignArrow(Arrow* object, WaitableEvent* completion) {
 161     // Copy constructor.
 162     Arrow a = *object;
 163     // Assignment operator.
 164     *object = a;
 165     completion->Signal();
 166   }
 167
 168   static void DoCopyAndAssignArrowBase(
 169       Arrow* object,
 170       WaitableEvent* completion) {
 171     // Copy constructor.
 172     WeakPtr<TargetBase> b = object->target;
 173     // Assignment operator.
 174     WeakPtr<TargetBase> c;
 175     c = object->target;
 176     completion->Signal();
 177   }
 178
 179   static void DoDeleteArrow(Arrow* object, WaitableEvent* completion) {
 180     delete object;
 181     completion->Signal();
 182   }
 183 };
 184
 185 }  // namespace
 186
 187 TEST(WeakPtrFactoryTest, Basic) {
 188   int data;
 189   WeakPtrFactory<int> factory(&data);
 190   WeakPtr<int> ptr = factory.GetWeakPtr();
 191   EXPECT_EQ(&data, ptr.get());
 192 }
 193
 194 TEST(WeakPtrFactoryTest, Comparison) {
 195   int data;
 196   WeakPtrFactory<int> factory(&data);
 197   WeakPtr<int> ptr = factory.GetWeakPtr();
 198   WeakPtr<int> ptr2 = ptr;
 199   EXPECT_EQ(ptr.get(), ptr2.get());
 200 }
 201
 202 TEST(WeakPtrFactoryTest, OutOfScope) {
 203   WeakPtr<int> ptr;
 204   EXPECT_EQ(NULL, ptr.get());
 205   {
 206     int data;
 207     WeakPtrFactory<int> factory(&data);
 208     ptr = factory.GetWeakPtr();
 209   }
 210   EXPECT_EQ(NULL, ptr.get());
 211 }
 212
 213 TEST(WeakPtrFactoryTest, Multiple) {
 214   WeakPtr<int> a, b;
 215   {
 216     int data;
 217     WeakPtrFactory<int> factory(&data);
 218     a = factory.GetWeakPtr();
 219     b = factory.GetWeakPtr();
 220     EXPECT_EQ(&data, a.get());
 221     EXPECT_EQ(&data, b.get());
 222   }
 223   EXPECT_EQ(NULL, a.get());
 224   EXPECT_EQ(NULL, b.get());
 225 }
 226
 227 TEST(WeakPtrFactoryTest, MultipleStaged) {
 228   WeakPtr<int> a;
 229   {
 230     int data;
 231     WeakPtrFactory<int> factory(&data);
 232     a = factory.GetWeakPtr();
 233     {
 234       WeakPtr<int> b = factory.GetWeakPtr();
 235     }
 236     EXPECT_TRUE(NULL != a.get());
 237   }
 238   EXPECT_EQ(NULL, a.get());
 239 }
 240
 241 TEST(WeakPtrFactoryTest, Dereference) {
 242   Base data;
 243   data.member = "123456";
 244   WeakPtrFactory<Base> factory(&data);
 245   WeakPtr<Base> ptr = factory.GetWeakPtr();
 246   EXPECT_EQ(&data, ptr.get());
 247   EXPECT_EQ(data.member, (*ptr).member);
 248   EXPECT_EQ(data.member, ptr->member);
 249 }
 250
 251 TEST(WeakPtrFactoryTest, UpCast) {
 252   Derived data;
 253   WeakPtrFactory<Derived> factory(&data);
 254   WeakPtr<Base> ptr = factory.GetWeakPtr();
 255   ptr = factory.GetWeakPtr();
 256   EXPECT_EQ(ptr.get(), &data);
 257 }
 258
 259 TEST(WeakPtrTest, SupportsWeakPtr) {
 260   Target target;
 261   WeakPtr<Target> ptr = target.AsWeakPtr();
 262   EXPECT_EQ(&target, ptr.get());
 263 }
 264
 265 TEST(WeakPtrTest, DerivedTarget) {
 266   DerivedTarget target;
 267   WeakPtr<DerivedTarget> ptr = AsWeakPtr(&target);
 268   EXPECT_EQ(&target, ptr.get());
 269 }
 270
 271 TEST(WeakPtrTest, InvalidateWeakPtrs) {
 272   int data;
 273   WeakPtrFactory<int> factory(&data);
 274   WeakPtr<int> ptr = factory.GetWeakPtr();
 275   EXPECT_EQ(&data, ptr.get());
 276   EXPECT_TRUE(factory.HasWeakPtrs());
 277   factory.InvalidateWeakPtrs();
 278   EXPECT_EQ(NULL, ptr.get());
 279   EXPECT_FALSE(factory.HasWeakPtrs());
 280
 281   // Test that the factory can create new weak pointers after a
 282   // InvalidateWeakPtrs call, and they remain valid until the next
 283   // InvalidateWeakPtrs call.
 284   WeakPtr<int> ptr2 = factory.GetWeakPtr();
 285   EXPECT_EQ(&data, ptr2.get());
 286   EXPECT_TRUE(factory.HasWeakPtrs());
 287   factory.InvalidateWeakPtrs();
 288   EXPECT_EQ(NULL, ptr2.get());
 289   EXPECT_FALSE(factory.HasWeakPtrs());
 290 }
 291
 292 TEST(WeakPtrTest, HasWeakPtrs) {
 293   int data;
 294   WeakPtrFactory<int> factory(&data);
 295   {
 296     WeakPtr<int> ptr = factory.GetWeakPtr();
 297     EXPECT_TRUE(factory.HasWeakPtrs());
 298   }
 299   EXPECT_FALSE(factory.HasWeakPtrs());
 300 }
 301
 302 TEST(WeakPtrTest, ObjectAndWeakPtrOnDifferentThreads) {
 303   // Test that it is OK to create an object that supports WeakPtr on one thread,
 304   // but use it on another.  This tests that we do not trip runtime checks that
 305   // ensure that a WeakPtr is not used by multiple threads.
 306   scoped_ptr<Target> target(OffThreadObjectCreator<Target>::NewObject());
 307   WeakPtr<Target> weak_ptr = target->AsWeakPtr();
 308   EXPECT_EQ(target.get(), weak_ptr.get());
 309 }
 310
 311 TEST(WeakPtrTest, WeakPtrInitiateAndUseOnDifferentThreads) {
 312   // Test that it is OK to create an object that has a WeakPtr member on one
 313   // thread, but use it on another.  This tests that we do not trip runtime
 314   // checks that ensure that a WeakPtr is not used by multiple threads.
 315   scoped_ptr<Arrow> arrow(OffThreadObjectCreator<Arrow>::NewObject());
 316   Target target;
 317   arrow->target = target.AsWeakPtr();
 318   EXPECT_EQ(&target, arrow->target.get());
 319 }
 320
 321 TEST(WeakPtrTest, MoveOwnershipImplicitly) {
 322   // Move object ownership to another thread by releasing all weak pointers
 323   // on the original thread first, and then establish WeakPtr on a different
 324   // thread.
 325   BackgroundThread background;
 326   background.Start();
 327
 328   Target* target = new Target();
 329   {
 330     WeakPtr<Target> weak_ptr = target->AsWeakPtr();
 331     // Main thread deletes the WeakPtr, then the thread ownership of the
 332     // object can be implicitly moved.
 333   }
 334   Arrow* arrow;
 335
 336   // Background thread creates WeakPtr(and implicitly owns the object).
 337   background.CreateArrowFromTarget(&arrow, target);
 338   EXPECT_EQ(background.DeRef(arrow), target);
 339
 340   {
 341     // Main thread creates another WeakPtr, but this does not trigger implicitly
 342     // thread ownership move.
 343     Arrow arrow;
 344     arrow.target = target->AsWeakPtr();
 345
 346     // The new WeakPtr is owned by background thread.
 347     EXPECT_EQ(target, background.DeRef(&arrow));
 348   }
 349
 350   // Target can only be deleted on background thread.
 351   background.DeleteTarget(target);
 352   background.DeleteArrow(arrow);
 353 }
 354
 355 TEST(WeakPtrTest, MoveOwnershipOfUnreferencedObject) {
 356   BackgroundThread background;
 357   background.Start();
 358
 359   Arrow* arrow;
 360   {
 361     Target target;
 362     // Background thread creates WeakPtr.
 363     background.CreateArrowFromTarget(&arrow, &target);
 364
 365     // Bind to background thread.
 366     EXPECT_EQ(&target, background.DeRef(arrow));
 367
 368     // Release the only WeakPtr.
 369     arrow->target.reset();
 370
 371     // Now we should be able to create a new reference from this thread.
 372     arrow->target = target.AsWeakPtr();
 373
 374     // Re-bind to main thread.
 375     EXPECT_EQ(&target, arrow->target.get());
 376
 377     // And the main thread can now delete the target.
 378   }
 379
 380   delete arrow;
 381 }
 382
 383 TEST(WeakPtrTest, MoveOwnershipAfterInvalidate) {
 384   BackgroundThread background;
 385   background.Start();
 386
 387   Arrow arrow;
 388   scoped_ptr<TargetWithFactory> target(new TargetWithFactory);
 389
 390   // Bind to main thread.
 391   arrow.target = target->factory.GetWeakPtr();
 392   EXPECT_EQ(target.get(), arrow.target.get());
 393
 394   target->factory.InvalidateWeakPtrs();
 395   EXPECT_EQ(NULL, arrow.target.get());
 396
 397   arrow.target = target->factory.GetWeakPtr();
 398   // Re-bind to background thread.
 399   EXPECT_EQ(target.get(), background.DeRef(&arrow));
 400
 401   // And the background thread can now delete the target.
 402   background.DeleteTarget(target.release());
 403 }
 404
 405 TEST(WeakPtrTest, MainThreadRefOutlivesBackgroundThreadRef) {
 406   // Originating thread has a WeakPtr that outlives others.
 407   // - Main thread creates a WeakPtr
 408   // - Background thread creates a WeakPtr copy from the one in main thread
 409   // - Destruct the WeakPtr on background thread
 410   // - Destruct the WeakPtr on main thread
 411   BackgroundThread background;
 412   background.Start();
 413
 414   Target target;
 415   Arrow arrow;
 416   arrow.target = target.AsWeakPtr();
 417
 418   Arrow* arrow_copy;
 419   background.CreateArrowFromArrow(&arrow_copy, &arrow);
 420   EXPECT_EQ(arrow_copy->target.get(), &target);
 421   background.DeleteArrow(arrow_copy);
 422 }
 423
 424 TEST(WeakPtrTest, BackgroundThreadRefOutlivesMainThreadRef) {
 425   // Originating thread drops all references before another thread.
 426   // - Main thread creates a WeakPtr and passes copy to background thread
 427   // - Destruct the pointer on main thread
 428   // - Destruct the pointer on background thread
 429   BackgroundThread background;
 430   background.Start();
 431
 432   Target target;
 433   Arrow* arrow_copy;
 434   {
 435     Arrow arrow;
 436     arrow.target = target.AsWeakPtr();
 437     background.CreateArrowFromArrow(&arrow_copy, &arrow);
 438   }
 439   EXPECT_EQ(arrow_copy->target.get(), &target);
 440   background.DeleteArrow(arrow_copy);
 441 }
 442
 443 TEST(WeakPtrTest, OwnerThreadDeletesObject) {
 444   // Originating thread invalidates WeakPtrs while its held by other thread.
 445   // - Main thread creates WeakPtr and passes Copy to background thread
 446   // - Object gets destroyed on main thread
 447   //   (invalidates WeakPtr on background thread)
 448   // - WeakPtr gets destroyed on Thread B
 449   BackgroundThread background;
 450   background.Start();
 451   Arrow* arrow_copy;
 452   {
 453     Target target;
 454     Arrow arrow;
 455     arrow.target = target.AsWeakPtr();
 456     background.CreateArrowFromArrow(&arrow_copy, &arrow);
 457   }
 458   EXPECT_EQ(NULL, arrow_copy->target.get());
 459   background.DeleteArrow(arrow_copy);
 460 }
 461
 462 TEST(WeakPtrTest, NonOwnerThreadCanCopyAndAssignWeakPtr) {
 463   // Main thread creates a Target object.
 464   Target target;
 465   // Main thread creates an arrow referencing the Target.
 466   Arrow *arrow = new Arrow();
 467   arrow->target = target.AsWeakPtr();
 468
 469   // Background can copy and assign arrow (as well as the WeakPtr inside).
 470   BackgroundThread background;
 471   background.Start();
 472   background.CopyAndAssignArrow(arrow);
 473   background.DeleteArrow(arrow);
 474 }
 475
 476 TEST(WeakPtrTest, NonOwnerThreadCanCopyAndAssignWeakPtrBase) {
 477   // Main thread creates a Target object.
 478   Target target;
 479   // Main thread creates an arrow referencing the Target.
 480   Arrow *arrow = new Arrow();
 481   arrow->target = target.AsWeakPtr();
 482
 483   // Background can copy and assign arrow's WeakPtr to a base class WeakPtr.
 484   BackgroundThread background;
 485   background.Start();
 486   background.CopyAndAssignArrowBase(arrow);
 487   background.DeleteArrow(arrow);
 488 }
 489
 490 TEST(WeakPtrTest, NonOwnerThreadCanDeleteWeakPtr) {
 491   // Main thread creates a Target object.
 492   Target target;
 493   // Main thread creates an arrow referencing the Target.
 494   Arrow* arrow = new Arrow();
 495   arrow->target = target.AsWeakPtr();
 496
 497   // Background can delete arrow (as well as the WeakPtr inside).
 498   BackgroundThread background;
 499   background.Start();
 500   background.DeleteArrow(arrow);
 501 }
 502
 503 #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)) && GTEST_HAS_DEATH_TEST
 504
 505 TEST(WeakPtrDeathTest, WeakPtrCopyDoesNotChangeThreadBinding) {
 506   // The default style "fast" does not support multi-threaded tests
 507   // (introduces deadlock on Linux).
 508   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
 509
 510   BackgroundThread background;
 511   background.Start();
 512
 513   // Main thread creates a Target object.
 514   Target target;
 515   // Main thread creates an arrow referencing the Target.
 516   Arrow arrow;
 517   arrow.target = target.AsWeakPtr();
 518
 519   // Background copies the WeakPtr.
 520   Arrow* arrow_copy;
 521   background.CreateArrowFromArrow(&arrow_copy, &arrow);
 522
 523   // The copy is still bound to main thread so I can deref.
 524   EXPECT_EQ(arrow.target.get(), arrow_copy->target.get());
 525
 526   // Although background thread created the copy, it can not deref the copied
 527   // WeakPtr.
 528   ASSERT_DEATH(background.DeRef(arrow_copy), "");
 529
 530   background.DeleteArrow(arrow_copy);
 531 }
 532
 533 TEST(WeakPtrDeathTest, NonOwnerThreadDereferencesWeakPtrAfterReference) {
 534   // The default style "fast" does not support multi-threaded tests
 535   // (introduces deadlock on Linux).
 536   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
 537
 538   // Main thread creates a Target object.
 539   Target target;
 540
 541   // Main thread creates an arrow referencing the Target (so target's
 542   // thread ownership can not be implicitly moved).
 543   Arrow arrow;
 544   arrow.target = target.AsWeakPtr();
 545   arrow.target.get();
 546
 547   // Background thread tries to deref target, which violates thread ownership.
 548   BackgroundThread background;
 549   background.Start();
 550   ASSERT_DEATH(background.DeRef(&arrow), "");
 551 }
 552
 553 TEST(WeakPtrDeathTest, NonOwnerThreadDeletesWeakPtrAfterReference) {
 554   // The default style "fast" does not support multi-threaded tests
 555   // (introduces deadlock on Linux).
 556   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
 557
 558   scoped_ptr<Target> target(new Target());
 559
 560   // Main thread creates an arrow referencing the Target.
 561   Arrow arrow;
 562   arrow.target = target->AsWeakPtr();
 563
 564   // Background thread tries to deref target, binding it to the thread.
 565   BackgroundThread background;
 566   background.Start();
 567   background.DeRef(&arrow);
 568
 569   // Main thread deletes Target, violating thread binding.
 570   ASSERT_DEATH(target.reset(), "");
 571
 572   // |target.reset()| died so |target| still holds the object, so we
 573   // must pass it to the background thread to teardown.
 574   background.DeleteTarget(target.release());
 575 }
 576
 577 TEST(WeakPtrDeathTest, NonOwnerThreadDeletesObjectAfterReference) {
 578   // The default style "fast" does not support multi-threaded tests
 579   // (introduces deadlock on Linux).
 580   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
 581
 582   scoped_ptr<Target> target(new Target());
 583
 584   // Main thread creates an arrow referencing the Target, and references it, so
 585   // that it becomes bound to the thread.
 586   Arrow arrow;
 587   arrow.target = target->AsWeakPtr();
 588   arrow.target.get();
 589
 590   // Background thread tries to delete target, volating thread binding.
 591   BackgroundThread background;
 592   background.Start();
 593   ASSERT_DEATH(background.DeleteTarget(target.release()), "");
 594 }
 595
 596 TEST(WeakPtrDeathTest, NonOwnerThreadReferencesObjectAfterDeletion) {
 597   // The default style "fast" does not support multi-threaded tests
 598   // (introduces deadlock on Linux).
 599   ::testing::FLAGS_gtest_death_test_style = "threadsafe";
 600
 601   scoped_ptr<Target> target(new Target());
 602
 603   // Main thread creates an arrow referencing the Target.
 604   Arrow arrow;
 605   arrow.target = target->AsWeakPtr();
 606
 607   // Background thread tries to delete target, binding the object to the thread.
 608   BackgroundThread background;
 609   background.Start();
 610   background.DeleteTarget(target.release());
 611
 612   // Main thread attempts to dereference the target, violating thread binding.
 613   ASSERT_DEATH(arrow.target.get(), "");
 614 }
 615
 616 #endif
 617
 618 }  // namespace base