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 <memory> 8 #include <string> 9 10 #include "base/bind.h" 11 #include "base/debug/leak_annotations.h" 12 #include "base/location.h" 13 #include "base/single_thread_task_runner.h" 14 #include "base/synchronization/waitable_event.h" 15 #include "base/threading/thread.h" 16 #include "testing/gtest/include/gtest/gtest.h" 17 18 namespace base { 19 namespace { 20 21 WeakPtr<int> PassThru(WeakPtr<int> ptr) { 22 return ptr; 23 } 24 25 template <class T> 26 class OffThreadObjectCreator { 27 public: 28 static T* NewObject() { 29 T* result; 30 { 31 Thread creator_thread("creator_thread"); 32 creator_thread.Start(); 33 creator_thread.task_runner()->PostTask( 34 FROM_HERE, base::Bind(OffThreadObjectCreator::CreateObject, &result)); 35 } 36 DCHECK(result); // We synchronized on thread destruction above. 37 return result; 38 } 39 private: 40 static void CreateObject(T** result) { 41 *result = new T; 42 } 43 }; 44 45 struct Base { 46 std::string member; 47 }; 48 struct Derived : public Base {}; 49 50 struct TargetBase {}; 51 struct Target : public TargetBase, public SupportsWeakPtr<Target> { 52 virtual ~Target() {} 53 }; 54 struct DerivedTarget : public Target {}; 55 struct Arrow { 56 WeakPtr<Target> target; 57 }; 58 struct TargetWithFactory : public Target { 59 TargetWithFactory() : factory(this) {} 60 WeakPtrFactory<Target> factory; 61 }; 62 63 // Helper class to create and destroy weak pointer copies 64 // and delete objects on a background thread. 65 class BackgroundThread : public Thread { 66 public: 67 BackgroundThread() : Thread("owner_thread") {} 68 69 ~BackgroundThread() override { Stop(); } 70 71 void CreateArrowFromTarget(Arrow** arrow, Target* target) { 72 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 73 WaitableEvent::InitialState::NOT_SIGNALED); 74 task_runner()->PostTask( 75 FROM_HERE, base::Bind(&BackgroundThread::DoCreateArrowFromTarget, arrow, 76 target, &completion)); 77 completion.Wait(); 78 } 79 80 void CreateArrowFromArrow(Arrow** arrow, const Arrow* other) { 81 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 82 WaitableEvent::InitialState::NOT_SIGNALED); 83 task_runner()->PostTask( 84 FROM_HERE, base::Bind(&BackgroundThread::DoCreateArrowFromArrow, arrow, 85 other, &completion)); 86 completion.Wait(); 87 } 88 89 void DeleteTarget(Target* object) { 90 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 91 WaitableEvent::InitialState::NOT_SIGNALED); 92 task_runner()->PostTask( 93 FROM_HERE, 94 base::Bind(&BackgroundThread::DoDeleteTarget, object, &completion)); 95 completion.Wait(); 96 } 97 98 void CopyAndAssignArrow(Arrow* object) { 99 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 100 WaitableEvent::InitialState::NOT_SIGNALED); 101 task_runner()->PostTask( 102 FROM_HERE, base::Bind(&BackgroundThread::DoCopyAndAssignArrow, object, 103 &completion)); 104 completion.Wait(); 105 } 106 107 void CopyAndAssignArrowBase(Arrow* object) { 108 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 109 WaitableEvent::InitialState::NOT_SIGNALED); 110 task_runner()->PostTask( 111 FROM_HERE, base::Bind(&BackgroundThread::DoCopyAndAssignArrowBase, 112 object, &completion)); 113 completion.Wait(); 114 } 115 116 void DeleteArrow(Arrow* object) { 117 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 118 WaitableEvent::InitialState::NOT_SIGNALED); 119 task_runner()->PostTask( 120 FROM_HERE, 121 base::Bind(&BackgroundThread::DoDeleteArrow, object, &completion)); 122 completion.Wait(); 123 } 124 125 Target* DeRef(const Arrow* arrow) { 126 WaitableEvent completion(WaitableEvent::ResetPolicy::MANUAL, 127 WaitableEvent::InitialState::NOT_SIGNALED); 128 Target* result = nullptr; 129 task_runner()->PostTask(FROM_HERE, base::Bind(&BackgroundThread::DoDeRef, 130 arrow, &result, &completion)); 131 completion.Wait(); 132 return result; 133 } 134 135 protected: 136 static void DoCreateArrowFromArrow(Arrow** arrow, 137 const Arrow* other, 138 WaitableEvent* completion) { 139 *arrow = new Arrow; 140 **arrow = *other; 141 completion->Signal(); 142 } 143 144 static void DoCreateArrowFromTarget(Arrow** arrow, 145 Target* target, 146 WaitableEvent* completion) { 147 *arrow = new Arrow; 148 (*arrow)->target = target->AsWeakPtr(); 149 completion->Signal(); 150 } 151 152 static void DoDeRef(const Arrow* arrow, 153 Target** result, 154 WaitableEvent* completion) { 155 *result = arrow->target.get(); 156 completion->Signal(); 157 } 158 159 static void DoDeleteTarget(Target* object, WaitableEvent* completion) { 160 delete object; 161 completion->Signal(); 162 } 163 164 static void DoCopyAndAssignArrow(Arrow* object, WaitableEvent* completion) { 165 // Copy constructor. 166 Arrow a = *object; 167 // Assignment operator. 168 *object = a; 169 completion->Signal(); 170 } 171 172 static void DoCopyAndAssignArrowBase( 173 Arrow* object, 174 WaitableEvent* completion) { 175 // Copy constructor. 176 WeakPtr<TargetBase> b = object->target; 177 // Assignment operator. 178 WeakPtr<TargetBase> c; 179 c = object->target; 180 completion->Signal(); 181 } 182 183 static void DoDeleteArrow(Arrow* object, WaitableEvent* completion) { 184 delete object; 185 completion->Signal(); 186 } 187 }; 188 189 } // namespace 190 191 TEST(WeakPtrFactoryTest, Basic) { 192 int data; 193 WeakPtrFactory<int> factory(&data); 194 WeakPtr<int> ptr = factory.GetWeakPtr(); 195 EXPECT_EQ(&data, ptr.get()); 196 } 197 198 TEST(WeakPtrFactoryTest, Comparison) { 199 int data; 200 WeakPtrFactory<int> factory(&data); 201 WeakPtr<int> ptr = factory.GetWeakPtr(); 202 WeakPtr<int> ptr2 = ptr; 203 EXPECT_EQ(ptr.get(), ptr2.get()); 204 } 205 206 TEST(WeakPtrFactoryTest, Move) { 207 int data; 208 WeakPtrFactory<int> factory(&data); 209 WeakPtr<int> ptr = factory.GetWeakPtr(); 210 WeakPtr<int> ptr2 = factory.GetWeakPtr(); 211 WeakPtr<int> ptr3 = std::move(ptr2); 212 EXPECT_NE(ptr.get(), ptr2.get()); 213 EXPECT_EQ(ptr.get(), ptr3.get()); 214 } 215 216 TEST(WeakPtrFactoryTest, OutOfScope) { 217 WeakPtr<int> ptr; 218 EXPECT_EQ(nullptr, ptr.get()); 219 { 220 int data; 221 WeakPtrFactory<int> factory(&data); 222 ptr = factory.GetWeakPtr(); 223 } 224 EXPECT_EQ(nullptr, ptr.get()); 225 } 226 227 TEST(WeakPtrFactoryTest, Multiple) { 228 WeakPtr<int> a, b; 229 { 230 int data; 231 WeakPtrFactory<int> factory(&data); 232 a = factory.GetWeakPtr(); 233 b = factory.GetWeakPtr(); 234 EXPECT_EQ(&data, a.get()); 235 EXPECT_EQ(&data, b.get()); 236 } 237 EXPECT_EQ(nullptr, a.get()); 238 EXPECT_EQ(nullptr, b.get()); 239 } 240 241 TEST(WeakPtrFactoryTest, MultipleStaged) { 242 WeakPtr<int> a; 243 { 244 int data; 245 WeakPtrFactory<int> factory(&data); 246 a = factory.GetWeakPtr(); 247 { 248 WeakPtr<int> b = factory.GetWeakPtr(); 249 } 250 EXPECT_NE(nullptr, a.get()); 251 } 252 EXPECT_EQ(nullptr, a.get()); 253 } 254 255 TEST(WeakPtrFactoryTest, Dereference) { 256 Base data; 257 data.member = "123456"; 258 WeakPtrFactory<Base> factory(&data); 259 WeakPtr<Base> ptr = factory.GetWeakPtr(); 260 EXPECT_EQ(&data, ptr.get()); 261 EXPECT_EQ(data.member, (*ptr).member); 262 EXPECT_EQ(data.member, ptr->member); 263 } 264 265 TEST(WeakPtrFactoryTest, UpCast) { 266 Derived data; 267 WeakPtrFactory<Derived> factory(&data); 268 WeakPtr<Base> ptr = factory.GetWeakPtr(); 269 ptr = factory.GetWeakPtr(); 270 EXPECT_EQ(ptr.get(), &data); 271 } 272 273 TEST(WeakPtrTest, ConstructFromNullptr) { 274 WeakPtr<int> ptr = PassThru(nullptr); 275 EXPECT_EQ(nullptr, ptr.get()); 276 } 277 278 TEST(WeakPtrTest, SupportsWeakPtr) { 279 Target target; 280 WeakPtr<Target> ptr = target.AsWeakPtr(); 281 EXPECT_EQ(&target, ptr.get()); 282 } 283 284 TEST(WeakPtrTest, DerivedTarget) { 285 DerivedTarget target; 286 WeakPtr<DerivedTarget> ptr = AsWeakPtr(&target); 287 EXPECT_EQ(&target, ptr.get()); 288 } 289 290 TEST(WeakPtrFactoryTest, BooleanTesting) { 291 int data; 292 WeakPtrFactory<int> factory(&data); 293 294 WeakPtr<int> ptr_to_an_instance = factory.GetWeakPtr(); 295 EXPECT_TRUE(ptr_to_an_instance); 296 EXPECT_FALSE(!ptr_to_an_instance); 297 298 if (ptr_to_an_instance) { 299 } else { 300 ADD_FAILURE() << "Pointer to an instance should result in true."; 301 } 302 303 if (!ptr_to_an_instance) { // check for operator!(). 304 ADD_FAILURE() << "Pointer to an instance should result in !x being false."; 305 } 306 307 WeakPtr<int> null_ptr; 308 EXPECT_FALSE(null_ptr); 309 EXPECT_TRUE(!null_ptr); 310 311 if (null_ptr) { 312 ADD_FAILURE() << "Null pointer should result in false."; 313 } 314 315 if (!null_ptr) { // check for operator!(). 316 } else { 317 ADD_FAILURE() << "Null pointer should result in !x being true."; 318 } 319 } 320 321 TEST(WeakPtrFactoryTest, ComparisonToNull) { 322 int data; 323 WeakPtrFactory<int> factory(&data); 324 325 WeakPtr<int> ptr_to_an_instance = factory.GetWeakPtr(); 326 EXPECT_NE(nullptr, ptr_to_an_instance); 327 EXPECT_NE(ptr_to_an_instance, nullptr); 328 329 WeakPtr<int> null_ptr; 330 EXPECT_EQ(null_ptr, nullptr); 331 EXPECT_EQ(nullptr, null_ptr); 332 } 333 334 TEST(WeakPtrTest, InvalidateWeakPtrs) { 335 int data; 336 WeakPtrFactory<int> factory(&data); 337 WeakPtr<int> ptr = factory.GetWeakPtr(); 338 EXPECT_EQ(&data, ptr.get()); 339 EXPECT_TRUE(factory.HasWeakPtrs()); 340 factory.InvalidateWeakPtrs(); 341 EXPECT_EQ(nullptr, ptr.get()); 342 EXPECT_FALSE(factory.HasWeakPtrs()); 343 344 // Test that the factory can create new weak pointers after a 345 // InvalidateWeakPtrs call, and they remain valid until the next 346 // InvalidateWeakPtrs call. 347 WeakPtr<int> ptr2 = factory.GetWeakPtr(); 348 EXPECT_EQ(&data, ptr2.get()); 349 EXPECT_TRUE(factory.HasWeakPtrs()); 350 factory.InvalidateWeakPtrs(); 351 EXPECT_EQ(nullptr, ptr2.get()); 352 EXPECT_FALSE(factory.HasWeakPtrs()); 353 } 354 355 TEST(WeakPtrTest, HasWeakPtrs) { 356 int data; 357 WeakPtrFactory<int> factory(&data); 358 { 359 WeakPtr<int> ptr = factory.GetWeakPtr(); 360 EXPECT_TRUE(factory.HasWeakPtrs()); 361 } 362 EXPECT_FALSE(factory.HasWeakPtrs()); 363 } 364 365 TEST(WeakPtrTest, ObjectAndWeakPtrOnDifferentThreads) { 366 // Test that it is OK to create an object that supports WeakPtr on one thread, 367 // but use it on another. This tests that we do not trip runtime checks that 368 // ensure that a WeakPtr is not used by multiple threads. 369 std::unique_ptr<Target> target(OffThreadObjectCreator<Target>::NewObject()); 370 WeakPtr<Target> weak_ptr = target->AsWeakPtr(); 371 EXPECT_EQ(target.get(), weak_ptr.get()); 372 } 373 374 TEST(WeakPtrTest, WeakPtrInitiateAndUseOnDifferentThreads) { 375 // Test that it is OK to create an object that has a WeakPtr member on one 376 // thread, but use it on another. This tests that we do not trip runtime 377 // checks that ensure that a WeakPtr is not used by multiple threads. 378 std::unique_ptr<Arrow> arrow(OffThreadObjectCreator<Arrow>::NewObject()); 379 Target target; 380 arrow->target = target.AsWeakPtr(); 381 EXPECT_EQ(&target, arrow->target.get()); 382 } 383 384 TEST(WeakPtrTest, MoveOwnershipImplicitly) { 385 // Move object ownership to another thread by releasing all weak pointers 386 // on the original thread first, and then establish WeakPtr on a different 387 // thread. 388 BackgroundThread background; 389 background.Start(); 390 391 Target* target = new Target(); 392 { 393 WeakPtr<Target> weak_ptr = target->AsWeakPtr(); 394 // Main thread deletes the WeakPtr, then the thread ownership of the 395 // object can be implicitly moved. 396 } 397 Arrow* arrow; 398 399 // Background thread creates WeakPtr(and implicitly owns the object). 400 background.CreateArrowFromTarget(&arrow, target); 401 EXPECT_EQ(background.DeRef(arrow), target); 402 403 { 404 // Main thread creates another WeakPtr, but this does not trigger implicitly 405 // thread ownership move. 406 Arrow arrow; 407 arrow.target = target->AsWeakPtr(); 408 409 // The new WeakPtr is owned by background thread. 410 EXPECT_EQ(target, background.DeRef(&arrow)); 411 } 412 413 // Target can only be deleted on background thread. 414 background.DeleteTarget(target); 415 background.DeleteArrow(arrow); 416 } 417 418 TEST(WeakPtrTest, MoveOwnershipOfUnreferencedObject) { 419 BackgroundThread background; 420 background.Start(); 421 422 Arrow* arrow; 423 { 424 Target target; 425 // Background thread creates WeakPtr. 426 background.CreateArrowFromTarget(&arrow, &target); 427 428 // Bind to background thread. 429 EXPECT_EQ(&target, background.DeRef(arrow)); 430 431 // Release the only WeakPtr. 432 arrow->target.reset(); 433 434 // Now we should be able to create a new reference from this thread. 435 arrow->target = target.AsWeakPtr(); 436 437 // Re-bind to main thread. 438 EXPECT_EQ(&target, arrow->target.get()); 439 440 // And the main thread can now delete the target. 441 } 442 443 delete arrow; 444 } 445 446 TEST(WeakPtrTest, MoveOwnershipAfterInvalidate) { 447 BackgroundThread background; 448 background.Start(); 449 450 Arrow arrow; 451 std::unique_ptr<TargetWithFactory> target(new TargetWithFactory); 452 453 // Bind to main thread. 454 arrow.target = target->factory.GetWeakPtr(); 455 EXPECT_EQ(target.get(), arrow.target.get()); 456 457 target->factory.InvalidateWeakPtrs(); 458 EXPECT_EQ(nullptr, arrow.target.get()); 459 460 arrow.target = target->factory.GetWeakPtr(); 461 // Re-bind to background thread. 462 EXPECT_EQ(target.get(), background.DeRef(&arrow)); 463 464 // And the background thread can now delete the target. 465 background.DeleteTarget(target.release()); 466 } 467 468 TEST(WeakPtrTest, MainThreadRefOutlivesBackgroundThreadRef) { 469 // Originating thread has a WeakPtr that outlives others. 470 // - Main thread creates a WeakPtr 471 // - Background thread creates a WeakPtr copy from the one in main thread 472 // - Destruct the WeakPtr on background thread 473 // - Destruct the WeakPtr on main thread 474 BackgroundThread background; 475 background.Start(); 476 477 Target target; 478 Arrow arrow; 479 arrow.target = target.AsWeakPtr(); 480 481 Arrow* arrow_copy; 482 background.CreateArrowFromArrow(&arrow_copy, &arrow); 483 EXPECT_EQ(arrow_copy->target.get(), &target); 484 background.DeleteArrow(arrow_copy); 485 } 486 487 TEST(WeakPtrTest, BackgroundThreadRefOutlivesMainThreadRef) { 488 // Originating thread drops all references before another thread. 489 // - Main thread creates a WeakPtr and passes copy to background thread 490 // - Destruct the pointer on main thread 491 // - Destruct the pointer on background thread 492 BackgroundThread background; 493 background.Start(); 494 495 Target target; 496 Arrow* arrow_copy; 497 { 498 Arrow arrow; 499 arrow.target = target.AsWeakPtr(); 500 background.CreateArrowFromArrow(&arrow_copy, &arrow); 501 } 502 EXPECT_EQ(arrow_copy->target.get(), &target); 503 background.DeleteArrow(arrow_copy); 504 } 505 506 TEST(WeakPtrTest, OwnerThreadDeletesObject) { 507 // Originating thread invalidates WeakPtrs while its held by other thread. 508 // - Main thread creates WeakPtr and passes Copy to background thread 509 // - Object gets destroyed on main thread 510 // (invalidates WeakPtr on background thread) 511 // - WeakPtr gets destroyed on Thread B 512 BackgroundThread background; 513 background.Start(); 514 Arrow* arrow_copy; 515 { 516 Target target; 517 Arrow arrow; 518 arrow.target = target.AsWeakPtr(); 519 background.CreateArrowFromArrow(&arrow_copy, &arrow); 520 } 521 EXPECT_EQ(nullptr, arrow_copy->target.get()); 522 background.DeleteArrow(arrow_copy); 523 } 524 525 TEST(WeakPtrTest, NonOwnerThreadCanCopyAndAssignWeakPtr) { 526 // Main thread creates a Target object. 527 Target target; 528 // Main thread creates an arrow referencing the Target. 529 Arrow *arrow = new Arrow(); 530 arrow->target = target.AsWeakPtr(); 531 532 // Background can copy and assign arrow (as well as the WeakPtr inside). 533 BackgroundThread background; 534 background.Start(); 535 background.CopyAndAssignArrow(arrow); 536 background.DeleteArrow(arrow); 537 } 538 539 TEST(WeakPtrTest, NonOwnerThreadCanCopyAndAssignWeakPtrBase) { 540 // Main thread creates a Target object. 541 Target target; 542 // Main thread creates an arrow referencing the Target. 543 Arrow *arrow = new Arrow(); 544 arrow->target = target.AsWeakPtr(); 545 546 // Background can copy and assign arrow's WeakPtr to a base class WeakPtr. 547 BackgroundThread background; 548 background.Start(); 549 background.CopyAndAssignArrowBase(arrow); 550 background.DeleteArrow(arrow); 551 } 552 553 TEST(WeakPtrTest, NonOwnerThreadCanDeleteWeakPtr) { 554 // Main thread creates a Target object. 555 Target target; 556 // Main thread creates an arrow referencing the Target. 557 Arrow* arrow = new Arrow(); 558 arrow->target = target.AsWeakPtr(); 559 560 // Background can delete arrow (as well as the WeakPtr inside). 561 BackgroundThread background; 562 background.Start(); 563 background.DeleteArrow(arrow); 564 } 565 566 #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)) && GTEST_HAS_DEATH_TEST 567 568 TEST(WeakPtrDeathTest, WeakPtrCopyDoesNotChangeThreadBinding) { 569 // The default style "fast" does not support multi-threaded tests 570 // (introduces deadlock on Linux). 571 ::testing::FLAGS_gtest_death_test_style = "threadsafe"; 572 573 BackgroundThread background; 574 background.Start(); 575 576 // Main thread creates a Target object. 577 Target target; 578 // Main thread creates an arrow referencing the Target. 579 Arrow arrow; 580 arrow.target = target.AsWeakPtr(); 581 582 // Background copies the WeakPtr. 583 Arrow* arrow_copy; 584 background.CreateArrowFromArrow(&arrow_copy, &arrow); 585 586 // The copy is still bound to main thread so I can deref. 587 EXPECT_EQ(arrow.target.get(), arrow_copy->target.get()); 588 589 // Although background thread created the copy, it can not deref the copied 590 // WeakPtr. 591 ASSERT_DEATH(background.DeRef(arrow_copy), ""); 592 593 background.DeleteArrow(arrow_copy); 594 } 595 596 TEST(WeakPtrDeathTest, NonOwnerThreadDereferencesWeakPtrAfterReference) { 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 // Main thread creates a Target object. 602 Target target; 603 604 // Main thread creates an arrow referencing the Target (so target's 605 // thread ownership can not be implicitly moved). 606 Arrow arrow; 607 arrow.target = target.AsWeakPtr(); 608 arrow.target.get(); 609 610 // Background thread tries to deref target, which violates thread ownership. 611 BackgroundThread background; 612 background.Start(); 613 ASSERT_DEATH(background.DeRef(&arrow), ""); 614 } 615 616 TEST(WeakPtrDeathTest, NonOwnerThreadDeletesWeakPtrAfterReference) { 617 // The default style "fast" does not support multi-threaded tests 618 // (introduces deadlock on Linux). 619 ::testing::FLAGS_gtest_death_test_style = "threadsafe"; 620 621 std::unique_ptr<Target> target(new Target()); 622 623 // Main thread creates an arrow referencing the Target. 624 Arrow arrow; 625 arrow.target = target->AsWeakPtr(); 626 627 // Background thread tries to deref target, binding it to the thread. 628 BackgroundThread background; 629 background.Start(); 630 background.DeRef(&arrow); 631 632 // Main thread deletes Target, violating thread binding. 633 ASSERT_DEATH(target.reset(), ""); 634 635 // |target.reset()| died so |target| still holds the object, so we 636 // must pass it to the background thread to teardown. 637 background.DeleteTarget(target.release()); 638 } 639 640 TEST(WeakPtrDeathTest, NonOwnerThreadDeletesObjectAfterReference) { 641 // The default style "fast" does not support multi-threaded tests 642 // (introduces deadlock on Linux). 643 ::testing::FLAGS_gtest_death_test_style = "threadsafe"; 644 645 std::unique_ptr<Target> target(new Target()); 646 647 // Main thread creates an arrow referencing the Target, and references it, so 648 // that it becomes bound to the thread. 649 Arrow arrow; 650 arrow.target = target->AsWeakPtr(); 651 arrow.target.get(); 652 653 // Background thread tries to delete target, volating thread binding. 654 BackgroundThread background; 655 background.Start(); 656 ASSERT_DEATH(background.DeleteTarget(target.release()), ""); 657 } 658 659 TEST(WeakPtrDeathTest, NonOwnerThreadReferencesObjectAfterDeletion) { 660 // The default style "fast" does not support multi-threaded tests 661 // (introduces deadlock on Linux). 662 ::testing::FLAGS_gtest_death_test_style = "threadsafe"; 663 664 std::unique_ptr<Target> target(new Target()); 665 666 // Main thread creates an arrow referencing the Target. 667 Arrow arrow; 668 arrow.target = target->AsWeakPtr(); 669 670 // Background thread tries to delete target, binding the object to the thread. 671 BackgroundThread background; 672 background.Start(); 673 background.DeleteTarget(target.release()); 674 675 // Main thread attempts to dereference the target, violating thread binding. 676 ASSERT_DEATH(arrow.target.get(), ""); 677 } 678 679 #endif 680 681 } // namespace base 682