libutils/RefBase_test.cpp - android-core - Git at Google

 /*
  * Copyright (C) 2016 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <gtest/gtest.h>

 #include <utils/StrongPointer.h>
 #include <utils/RefBase.h>

 #include <thread>
 #include <atomic>
 #include <sched.h>
 #include <errno.h>

 // Enhanced version of StrongPointer_test, but using RefBase underneath.

 using namespace android;

 static constexpr int NITERS = 1000000;

 static constexpr int INITIAL_STRONG_VALUE = 1 << 28;  // Mirroring RefBase definition.

 class Foo : public RefBase {
 public:
     Foo(bool* deleted_check) : mDeleted(deleted_check) {
         *mDeleted = false;
     }

     ~Foo() {
         *mDeleted = true;
     }
 private:
     bool* mDeleted;
 };

 // A version of Foo that ensures that all objects are allocated at the same
 // address. No more than one can be allocated at a time. Thread-hostile.
 class FooFixedAlloc : public RefBase {
 public:
     static void* operator new(size_t size) {
         if (mAllocCount != 0) {
             abort();
         }
         mAllocCount = 1;
         if (theMemory == nullptr) {
             theMemory = malloc(size);
         }
         return theMemory;
     }

     static void operator delete(void *p) {
         if (mAllocCount != 1 || p != theMemory) {
             abort();
         }
         mAllocCount = 0;
     }

     FooFixedAlloc(bool* deleted_check) : mDeleted(deleted_check) {
         *mDeleted = false;
     }

     ~FooFixedAlloc() {
         *mDeleted = true;
     }
 private:
     bool* mDeleted;
     static int mAllocCount;
     static void* theMemory;
 };

 int FooFixedAlloc::mAllocCount(0);
 void* FooFixedAlloc::theMemory(nullptr);

 TEST(RefBase, StrongMoves) {
     bool isDeleted;
     Foo* foo = new Foo(&isDeleted);
     ASSERT_EQ(INITIAL_STRONG_VALUE, foo->getStrongCount());
     ASSERT_FALSE(isDeleted) << "Already deleted...?";
     sp<Foo> sp1(foo);
     wp<Foo> wp1(sp1);
     ASSERT_EQ(1, foo->getStrongCount());
     // Weak count includes both strong and weak references.
     ASSERT_EQ(2, foo->getWeakRefs()->getWeakCount());
     {
         sp<Foo> sp2 = std::move(sp1);
         ASSERT_EQ(1, foo->getStrongCount())
                 << "std::move failed, incremented refcnt";
         ASSERT_EQ(nullptr, sp1.get()) << "std::move failed, sp1 is still valid";
         // The strong count isn't increasing, let's double check the old object
         // is properly reset and doesn't early delete
         sp1 = std::move(sp2);
     }
     ASSERT_FALSE(isDeleted) << "deleted too early! still has a reference!";
     {
         // Now let's double check it deletes on time
         sp<Foo> sp2 = std::move(sp1);
     }
     ASSERT_TRUE(isDeleted) << "foo was leaked!";
     ASSERT_TRUE(wp1.promote().get() == nullptr);
 }

 TEST(RefBase, WeakCopies) {
     bool isDeleted;
     Foo* foo = new Foo(&isDeleted);
     EXPECT_EQ(0, foo->getWeakRefs()->getWeakCount());
     ASSERT_FALSE(isDeleted) << "Foo (weak) already deleted...?";
     wp<Foo> wp1(foo);
     EXPECT_EQ(1, foo->getWeakRefs()->getWeakCount());
     {
         wp<Foo> wp2 = wp1;
         ASSERT_EQ(2, foo->getWeakRefs()->getWeakCount());
     }
     EXPECT_EQ(1, foo->getWeakRefs()->getWeakCount());
     ASSERT_FALSE(isDeleted) << "deleted too early! still has a reference!";
     wp1 = nullptr;
     ASSERT_FALSE(isDeleted) << "Deletion on wp destruction should no longer occur";
 }

 TEST(RefBase, Comparisons) {
     bool isDeleted, isDeleted2, isDeleted3;
     Foo* foo = new Foo(&isDeleted);
     Foo* foo2 = new Foo(&isDeleted2);
     sp<Foo> sp1(foo);
     sp<Foo> sp2(foo2);
     wp<Foo> wp1(sp1);
     wp<Foo> wp2(sp1);
     wp<Foo> wp3(sp2);
     ASSERT_TRUE(wp1 == wp2);
     ASSERT_TRUE(wp1 == sp1);
     ASSERT_TRUE(wp3 == sp2);
     ASSERT_TRUE(wp1 != sp2);
     ASSERT_TRUE(wp1 <= wp2);
     ASSERT_TRUE(wp1 >= wp2);
     ASSERT_FALSE(wp1 != wp2);
     ASSERT_FALSE(wp1 > wp2);
     ASSERT_FALSE(wp1 < wp2);
     ASSERT_FALSE(sp1 == sp2);
     ASSERT_TRUE(sp1 != sp2);
     bool sp1_smaller = sp1 < sp2;
     wp<Foo>wp_smaller = sp1_smaller ? wp1 : wp3;
     wp<Foo>wp_larger = sp1_smaller ? wp3 : wp1;
     ASSERT_TRUE(wp_smaller < wp_larger);
     ASSERT_TRUE(wp_smaller != wp_larger);
     ASSERT_TRUE(wp_smaller <= wp_larger);
     ASSERT_FALSE(wp_smaller == wp_larger);
     ASSERT_FALSE(wp_smaller > wp_larger);
     ASSERT_FALSE(wp_smaller >= wp_larger);
     sp2 = nullptr;
     ASSERT_TRUE(isDeleted2);
     ASSERT_FALSE(isDeleted);
     ASSERT_FALSE(wp3 == sp2);
     // Comparison results on weak pointers should not be affected.
     ASSERT_TRUE(wp_smaller < wp_larger);
     ASSERT_TRUE(wp_smaller != wp_larger);
     ASSERT_TRUE(wp_smaller <= wp_larger);
     ASSERT_FALSE(wp_smaller == wp_larger);
     ASSERT_FALSE(wp_smaller > wp_larger);
     ASSERT_FALSE(wp_smaller >= wp_larger);
     wp2 = nullptr;
     ASSERT_FALSE(wp1 == wp2);
     ASSERT_TRUE(wp1 != wp2);
     wp1.clear();
     ASSERT_TRUE(wp1 == wp2);
     ASSERT_FALSE(wp1 != wp2);
     wp3.clear();
     ASSERT_TRUE(wp1 == wp3);
     ASSERT_FALSE(wp1 != wp3);
     ASSERT_FALSE(isDeleted);
     sp1.clear();
     ASSERT_TRUE(isDeleted);
     ASSERT_TRUE(sp1 == sp2);
     // Try to check that null pointers are properly initialized.
     {
         // Try once with non-null, to maximize chances of getting junk on the
         // stack.
         sp<Foo> sp3(new Foo(&isDeleted3));
         wp<Foo> wp4(sp3);
         wp<Foo> wp5;
         ASSERT_FALSE(wp4 == wp5);
         ASSERT_TRUE(wp4 != wp5);
         ASSERT_FALSE(sp3 == wp5);
         ASSERT_FALSE(wp5 == sp3);
         ASSERT_TRUE(sp3 != wp5);
         ASSERT_TRUE(wp5 != sp3);
         ASSERT_TRUE(sp3 == wp4);
     }
     {
         sp<Foo> sp3;
         wp<Foo> wp4(sp3);
         wp<Foo> wp5;
         ASSERT_TRUE(wp4 == wp5);
         ASSERT_FALSE(wp4 != wp5);
         ASSERT_TRUE(sp3 == wp5);
         ASSERT_TRUE(wp5 == sp3);
         ASSERT_FALSE(sp3 != wp5);
         ASSERT_FALSE(wp5 != sp3);
         ASSERT_TRUE(sp3 == wp4);
     }
 }

 // Check whether comparison against dead wp works, even if the object referenced
 // by the new wp happens to be at the same address.
 TEST(RefBase, ReplacedComparison) {
     bool isDeleted, isDeleted2;
     FooFixedAlloc* foo = new FooFixedAlloc(&isDeleted);
     sp<FooFixedAlloc> sp1(foo);
     wp<FooFixedAlloc> wp1(sp1);
     ASSERT_TRUE(wp1 == sp1);
     sp1.clear();  // Deallocates the object.
     ASSERT_TRUE(isDeleted);
     FooFixedAlloc* foo2 = new FooFixedAlloc(&isDeleted2);
     ASSERT_FALSE(isDeleted2);
     ASSERT_EQ(foo, foo2);  // Not technically a legal comparison, but ...
     sp<FooFixedAlloc> sp2(foo2);
     wp<FooFixedAlloc> wp2(sp2);
     ASSERT_TRUE(sp2 == wp2);
     ASSERT_FALSE(sp2 != wp2);
     ASSERT_TRUE(sp2 != wp1);
     ASSERT_FALSE(sp2 == wp1);
     ASSERT_FALSE(sp2 == sp1);  // sp1 is null.
     ASSERT_FALSE(wp1 == wp2);  // wp1 refers to old object.
     ASSERT_TRUE(wp1 != wp2);
     ASSERT_TRUE(wp1 > wp2 || wp1 < wp2);
     ASSERT_TRUE(wp1 >= wp2 || wp1 <= wp2);
     ASSERT_FALSE(wp1 >= wp2 && wp1 <= wp2);
     ASSERT_FALSE(wp1 == nullptr);
     wp1 = sp2;
     ASSERT_TRUE(wp1 == wp2);
     ASSERT_FALSE(wp1 != wp2);
 }

 // Set up a situation in which we race with visit2AndRremove() to delete
 // 2 strong references.  Bar destructor checks that there are no early
 // deletions and prior updates are visible to destructor.
 class Bar : public RefBase {
 public:
     Bar(std::atomic<int>* delete_count) : mVisited1(false), mVisited2(false),
             mDeleteCount(delete_count) {
     }

     ~Bar() {
         EXPECT_TRUE(mVisited1);
         EXPECT_TRUE(mVisited2);
         (*mDeleteCount)++;
     }
     bool mVisited1;
     bool mVisited2;
 private:
     std::atomic<int>* mDeleteCount;
 };

 static sp<Bar> buffer;
 static std::atomic<bool> bufferFull(false);

 // Wait until bufferFull has value val.
 static inline void waitFor(bool val) {
     while (bufferFull != val) {}
 }

 cpu_set_t otherCpus;

 // Divide the cpus we're allowed to run on into myCpus and otherCpus.
 // Set origCpus to the processors we were originally allowed to run on.
 // Return false if origCpus doesn't include at least processors 0 and 1.
 static bool setExclusiveCpus(cpu_set_t* origCpus /* out */,
         cpu_set_t* myCpus /* out */, cpu_set_t* otherCpus) {
     if (sched_getaffinity(0, sizeof(cpu_set_t), origCpus) != 0) {
         return false;
     }
     if (!CPU_ISSET(0,  origCpus) || !CPU_ISSET(1, origCpus)) {
         return false;
     }
     CPU_ZERO(myCpus);
     CPU_ZERO(otherCpus);
     CPU_OR(myCpus, myCpus, origCpus);
     CPU_OR(otherCpus, otherCpus, origCpus);
     for (unsigned i = 0; i < CPU_SETSIZE; ++i) {
         // I get the even cores, the other thread gets the odd ones.
         if (i & 1) {
             CPU_CLR(i, myCpus);
         } else {
             CPU_CLR(i, otherCpus);
         }
     }
     return true;
 }

 static void visit2AndRemove() {
     if (sched_setaffinity(0, sizeof(cpu_set_t), &otherCpus) != 0) {
         FAIL() << "setaffinity returned:" << errno;
     }
     for (int i = 0; i < NITERS; ++i) {
         waitFor(true);
         buffer->mVisited2 = true;
         buffer = nullptr;
         bufferFull = false;
     }
 }

 TEST(RefBase, RacingDestructors) {
     cpu_set_t origCpus;
     cpu_set_t myCpus;
     // Restrict us and the helper thread to disjoint cpu sets.
     // This prevents us from getting scheduled against each other,
     // which would be atrociously slow.
     if (setExclusiveCpus(&origCpus, &myCpus, &otherCpus)) {
         std::thread t(visit2AndRemove);
         std::atomic<int> deleteCount(0);
         if (sched_setaffinity(0, sizeof(cpu_set_t), &myCpus) != 0) {
             FAIL() << "setaffinity returned:" << errno;
         }
         for (int i = 0; i < NITERS; ++i) {
             waitFor(false);
             Bar* bar = new Bar(&deleteCount);
             sp<Bar> sp3(bar);
             buffer = sp3;
             bufferFull = true;
             ASSERT_TRUE(bar->getStrongCount() >= 1);
             // Weak count includes strong count.
             ASSERT_TRUE(bar->getWeakRefs()->getWeakCount() >= 1);
             sp3->mVisited1 = true;
             sp3 = nullptr;
         }
         t.join();
         if (sched_setaffinity(0, sizeof(cpu_set_t), &origCpus) != 0) {
             FAIL();
         }
         ASSERT_EQ(NITERS, deleteCount) << "Deletions missed!";
     }  // Otherwise this is slow and probably pointless on a uniprocessor.
 }

 static wp<Bar> wpBuffer;
 static std::atomic<bool> wpBufferFull(false);

 // Wait until wpBufferFull has value val.
 static inline void wpWaitFor(bool val) {
     while (wpBufferFull != val) {}
 }

 static void visit3AndRemove() {
     if (sched_setaffinity(0, sizeof(cpu_set_t), &otherCpus) != 0) {
         FAIL() << "setaffinity returned:" << errno;
     }
     for (int i = 0; i < NITERS; ++i) {
         wpWaitFor(true);
         {
             sp<Bar> sp1 = wpBuffer.promote();
             // We implicitly check that sp1 != NULL
             sp1->mVisited2 = true;
         }
         wpBuffer = nullptr;
         wpBufferFull = false;
     }
 }

 TEST(RefBase, RacingPromotions) {
     cpu_set_t origCpus;
     cpu_set_t myCpus;
     // Restrict us and the helper thread to disjoint cpu sets.
     // This prevents us from getting scheduled against each other,
     // which would be atrociously slow.
     if (setExclusiveCpus(&origCpus, &myCpus, &otherCpus)) {
         std::thread t(visit3AndRemove);
         std::atomic<int> deleteCount(0);
         if (sched_setaffinity(0, sizeof(cpu_set_t), &myCpus) != 0) {
             FAIL() << "setaffinity returned:" << errno;
         }
         for (int i = 0; i < NITERS; ++i) {
             Bar* bar = new Bar(&deleteCount);
             wp<Bar> wp1(bar);
             bar->mVisited1 = true;
             if (i % (NITERS / 10) == 0) {
                 // Do this rarely, since it generates a log message.
                 wp1 = nullptr;  // No longer destroys the object.
                 wp1 = bar;
             }
             wpBuffer = wp1;
             ASSERT_EQ(bar->getWeakRefs()->getWeakCount(), 2);
             wpBufferFull = true;
             // Promotion races with that in visit3AndRemove.
             // This may or may not succeed, but it shouldn't interfere with
             // the concurrent one.
             sp<Bar> sp1 = wp1.promote();
             wpWaitFor(false);  // Waits for other thread to drop strong pointer.
             sp1 = nullptr;
             // No strong pointers here.
             sp1 = wp1.promote();
             ASSERT_EQ(sp1.get(), nullptr) << "Dead wp promotion succeeded!";
         }
         t.join();
         if (sched_setaffinity(0, sizeof(cpu_set_t), &origCpus) != 0) {
             FAIL();
         }
         ASSERT_EQ(NITERS, deleteCount) << "Deletions missed!";
     }  // Otherwise this is slow and probably pointless on a uniprocessor.
 }
	/*
	* Copyright (C) 2016 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <gtest/gtest.h>

	#include <utils/StrongPointer.h>
	#include <utils/RefBase.h>

	#include <thread>
	#include <atomic>
	#include <sched.h>
	#include <errno.h>

	// Enhanced version of StrongPointer_test, but using RefBase underneath.

	using namespace android;

	static constexpr int NITERS = 1000000;

	static constexpr int INITIAL_STRONG_VALUE = 1 << 28; // Mirroring RefBase definition.

	class Foo : public RefBase {
	public:
	Foo(bool* deleted_check) : mDeleted(deleted_check) {
	*mDeleted = false;
	}

	~Foo() {
	*mDeleted = true;
	}
	private:
	bool* mDeleted;
	};

	// A version of Foo that ensures that all objects are allocated at the same
	// address. No more than one can be allocated at a time. Thread-hostile.
	class FooFixedAlloc : public RefBase {
	public:
	static void* operator new(size_t size) {
	if (mAllocCount != 0) {
	abort();
	}
	mAllocCount = 1;
	if (theMemory == nullptr) {
	theMemory = malloc(size);
	}
	return theMemory;
	}

	static void operator delete(void *p) {
	if (mAllocCount != 1 \|\| p != theMemory) {
	abort();
	}
	mAllocCount = 0;
	}

	FooFixedAlloc(bool* deleted_check) : mDeleted(deleted_check) {
	*mDeleted = false;
	}

	~FooFixedAlloc() {
	*mDeleted = true;
	}
	private:
	bool* mDeleted;
	static int mAllocCount;
	static void* theMemory;
	};

	int FooFixedAlloc::mAllocCount(0);
	void* FooFixedAlloc::theMemory(nullptr);

	TEST(RefBase, StrongMoves) {
	bool isDeleted;
	Foo* foo = new Foo(&isDeleted);
	ASSERT_EQ(INITIAL_STRONG_VALUE, foo->getStrongCount());
	ASSERT_FALSE(isDeleted) << "Already deleted...?";
	sp<Foo> sp1(foo);
	wp<Foo> wp1(sp1);
	ASSERT_EQ(1, foo->getStrongCount());
	// Weak count includes both strong and weak references.
	ASSERT_EQ(2, foo->getWeakRefs()->getWeakCount());
	{
	sp<Foo> sp2 = std::move(sp1);
	ASSERT_EQ(1, foo->getStrongCount())
	<< "std::move failed, incremented refcnt";
	ASSERT_EQ(nullptr, sp1.get()) << "std::move failed, sp1 is still valid";
	// The strong count isn't increasing, let's double check the old object
	// is properly reset and doesn't early delete
	sp1 = std::move(sp2);
	}
	ASSERT_FALSE(isDeleted) << "deleted too early! still has a reference!";
	{
	// Now let's double check it deletes on time
	sp<Foo> sp2 = std::move(sp1);
	}
	ASSERT_TRUE(isDeleted) << "foo was leaked!";
	ASSERT_TRUE(wp1.promote().get() == nullptr);
	}

	TEST(RefBase, WeakCopies) {
	bool isDeleted;
	Foo* foo = new Foo(&isDeleted);
	EXPECT_EQ(0, foo->getWeakRefs()->getWeakCount());
	ASSERT_FALSE(isDeleted) << "Foo (weak) already deleted...?";
	wp<Foo> wp1(foo);
	EXPECT_EQ(1, foo->getWeakRefs()->getWeakCount());
	{
	wp<Foo> wp2 = wp1;
	ASSERT_EQ(2, foo->getWeakRefs()->getWeakCount());
	}
	EXPECT_EQ(1, foo->getWeakRefs()->getWeakCount());
	ASSERT_FALSE(isDeleted) << "deleted too early! still has a reference!";
	wp1 = nullptr;
	ASSERT_FALSE(isDeleted) << "Deletion on wp destruction should no longer occur";
	}

	TEST(RefBase, Comparisons) {
	bool isDeleted, isDeleted2, isDeleted3;
	Foo* foo = new Foo(&isDeleted);
	Foo* foo2 = new Foo(&isDeleted2);
	sp<Foo> sp1(foo);
	sp<Foo> sp2(foo2);
	wp<Foo> wp1(sp1);
	wp<Foo> wp2(sp1);
	wp<Foo> wp3(sp2);
	ASSERT_TRUE(wp1 == wp2);
	ASSERT_TRUE(wp1 == sp1);
	ASSERT_TRUE(wp3 == sp2);
	ASSERT_TRUE(wp1 != sp2);
	ASSERT_TRUE(wp1 <= wp2);
	ASSERT_TRUE(wp1 >= wp2);
	ASSERT_FALSE(wp1 != wp2);
	ASSERT_FALSE(wp1 > wp2);
	ASSERT_FALSE(wp1 < wp2);
	ASSERT_FALSE(sp1 == sp2);
	ASSERT_TRUE(sp1 != sp2);
	bool sp1_smaller = sp1 < sp2;
	wp<Foo>wp_smaller = sp1_smaller ? wp1 : wp3;
	wp<Foo>wp_larger = sp1_smaller ? wp3 : wp1;
	ASSERT_TRUE(wp_smaller < wp_larger);
	ASSERT_TRUE(wp_smaller != wp_larger);
	ASSERT_TRUE(wp_smaller <= wp_larger);
	ASSERT_FALSE(wp_smaller == wp_larger);
	ASSERT_FALSE(wp_smaller > wp_larger);
	ASSERT_FALSE(wp_smaller >= wp_larger);
	sp2 = nullptr;
	ASSERT_TRUE(isDeleted2);
	ASSERT_FALSE(isDeleted);
	ASSERT_FALSE(wp3 == sp2);
	// Comparison results on weak pointers should not be affected.
	ASSERT_TRUE(wp_smaller < wp_larger);
	ASSERT_TRUE(wp_smaller != wp_larger);
	ASSERT_TRUE(wp_smaller <= wp_larger);
	ASSERT_FALSE(wp_smaller == wp_larger);
	ASSERT_FALSE(wp_smaller > wp_larger);
	ASSERT_FALSE(wp_smaller >= wp_larger);
	wp2 = nullptr;
	ASSERT_FALSE(wp1 == wp2);
	ASSERT_TRUE(wp1 != wp2);
	wp1.clear();
	ASSERT_TRUE(wp1 == wp2);
	ASSERT_FALSE(wp1 != wp2);
	wp3.clear();
	ASSERT_TRUE(wp1 == wp3);
	ASSERT_FALSE(wp1 != wp3);
	ASSERT_FALSE(isDeleted);
	sp1.clear();
	ASSERT_TRUE(isDeleted);
	ASSERT_TRUE(sp1 == sp2);
	// Try to check that null pointers are properly initialized.
	{
	// Try once with non-null, to maximize chances of getting junk on the
	// stack.
	sp<Foo> sp3(new Foo(&isDeleted3));
	wp<Foo> wp4(sp3);
	wp<Foo> wp5;
	ASSERT_FALSE(wp4 == wp5);
	ASSERT_TRUE(wp4 != wp5);
	ASSERT_FALSE(sp3 == wp5);
	ASSERT_FALSE(wp5 == sp3);
	ASSERT_TRUE(sp3 != wp5);
	ASSERT_TRUE(wp5 != sp3);
	ASSERT_TRUE(sp3 == wp4);
	}
	{
	sp<Foo> sp3;
	wp<Foo> wp4(sp3);
	wp<Foo> wp5;
	ASSERT_TRUE(wp4 == wp5);
	ASSERT_FALSE(wp4 != wp5);
	ASSERT_TRUE(sp3 == wp5);
	ASSERT_TRUE(wp5 == sp3);
	ASSERT_FALSE(sp3 != wp5);
	ASSERT_FALSE(wp5 != sp3);
	ASSERT_TRUE(sp3 == wp4);
	}
	}

	// Check whether comparison against dead wp works, even if the object referenced
	// by the new wp happens to be at the same address.
	TEST(RefBase, ReplacedComparison) {
	bool isDeleted, isDeleted2;
	FooFixedAlloc* foo = new FooFixedAlloc(&isDeleted);
	sp<FooFixedAlloc> sp1(foo);
	wp<FooFixedAlloc> wp1(sp1);
	ASSERT_TRUE(wp1 == sp1);
	sp1.clear(); // Deallocates the object.
	ASSERT_TRUE(isDeleted);
	FooFixedAlloc* foo2 = new FooFixedAlloc(&isDeleted2);
	ASSERT_FALSE(isDeleted2);
	ASSERT_EQ(foo, foo2); // Not technically a legal comparison, but ...
	sp<FooFixedAlloc> sp2(foo2);
	wp<FooFixedAlloc> wp2(sp2);
	ASSERT_TRUE(sp2 == wp2);
	ASSERT_FALSE(sp2 != wp2);
	ASSERT_TRUE(sp2 != wp1);
	ASSERT_FALSE(sp2 == wp1);
	ASSERT_FALSE(sp2 == sp1); // sp1 is null.
	ASSERT_FALSE(wp1 == wp2); // wp1 refers to old object.
	ASSERT_TRUE(wp1 != wp2);
	ASSERT_TRUE(wp1 > wp2 \|\| wp1 < wp2);
	ASSERT_TRUE(wp1 >= wp2 \|\| wp1 <= wp2);
	ASSERT_FALSE(wp1 >= wp2 && wp1 <= wp2);
	ASSERT_FALSE(wp1 == nullptr);
	wp1 = sp2;
	ASSERT_TRUE(wp1 == wp2);
	ASSERT_FALSE(wp1 != wp2);
	}

	// Set up a situation in which we race with visit2AndRremove() to delete
	// 2 strong references. Bar destructor checks that there are no early
	// deletions and prior updates are visible to destructor.
	class Bar : public RefBase {
	public:
	Bar(std::atomic<int>* delete_count) : mVisited1(false), mVisited2(false),
	mDeleteCount(delete_count) {
	}

	~Bar() {
	EXPECT_TRUE(mVisited1);
	EXPECT_TRUE(mVisited2);
	(*mDeleteCount)++;
	}
	bool mVisited1;
	bool mVisited2;
	private:
	std::atomic<int>* mDeleteCount;
	};

	static sp<Bar> buffer;
	static std::atomic<bool> bufferFull(false);

	// Wait until bufferFull has value val.
	static inline void waitFor(bool val) {
	while (bufferFull != val) {}
	}

	cpu_set_t otherCpus;

	// Divide the cpus we're allowed to run on into myCpus and otherCpus.
	// Set origCpus to the processors we were originally allowed to run on.
	// Return false if origCpus doesn't include at least processors 0 and 1.
	static bool setExclusiveCpus(cpu_set_t* origCpus /* out */,
	cpu_set_t* myCpus /* out /, cpu_set_t otherCpus) {
	if (sched_getaffinity(0, sizeof(cpu_set_t), origCpus) != 0) {
	return false;
	}
	if (!CPU_ISSET(0, origCpus) \|\| !CPU_ISSET(1, origCpus)) {
	return false;
	}
	CPU_ZERO(myCpus);
	CPU_ZERO(otherCpus);
	CPU_OR(myCpus, myCpus, origCpus);
	CPU_OR(otherCpus, otherCpus, origCpus);
	for (unsigned i = 0; i < CPU_SETSIZE; ++i) {
	// I get the even cores, the other thread gets the odd ones.
	if (i & 1) {
	CPU_CLR(i, myCpus);
	} else {
	CPU_CLR(i, otherCpus);
	}
	}
	return true;
	}

	static void visit2AndRemove() {
	if (sched_setaffinity(0, sizeof(cpu_set_t), &otherCpus) != 0) {
	FAIL() << "setaffinity returned:" << errno;
	}
	for (int i = 0; i < NITERS; ++i) {
	waitFor(true);
	buffer->mVisited2 = true;
	buffer = nullptr;
	bufferFull = false;
	}
	}

	TEST(RefBase, RacingDestructors) {
	cpu_set_t origCpus;
	cpu_set_t myCpus;
	// Restrict us and the helper thread to disjoint cpu sets.
	// This prevents us from getting scheduled against each other,
	// which would be atrociously slow.
	if (setExclusiveCpus(&origCpus, &myCpus, &otherCpus)) {
	std::thread t(visit2AndRemove);
	std::atomic<int> deleteCount(0);
	if (sched_setaffinity(0, sizeof(cpu_set_t), &myCpus) != 0) {
	FAIL() << "setaffinity returned:" << errno;
	}
	for (int i = 0; i < NITERS; ++i) {
	waitFor(false);
	Bar* bar = new Bar(&deleteCount);
	sp<Bar> sp3(bar);
	buffer = sp3;
	bufferFull = true;
	ASSERT_TRUE(bar->getStrongCount() >= 1);
	// Weak count includes strong count.
	ASSERT_TRUE(bar->getWeakRefs()->getWeakCount() >= 1);
	sp3->mVisited1 = true;
	sp3 = nullptr;
	}
	t.join();
	if (sched_setaffinity(0, sizeof(cpu_set_t), &origCpus) != 0) {
	FAIL();
	}
	ASSERT_EQ(NITERS, deleteCount) << "Deletions missed!";
	} // Otherwise this is slow and probably pointless on a uniprocessor.
	}

	static wp<Bar> wpBuffer;
	static std::atomic<bool> wpBufferFull(false);

	// Wait until wpBufferFull has value val.
	static inline void wpWaitFor(bool val) {
	while (wpBufferFull != val) {}
	}

	static void visit3AndRemove() {
	if (sched_setaffinity(0, sizeof(cpu_set_t), &otherCpus) != 0) {
	FAIL() << "setaffinity returned:" << errno;
	}
	for (int i = 0; i < NITERS; ++i) {
	wpWaitFor(true);
	{
	sp<Bar> sp1 = wpBuffer.promote();
	// We implicitly check that sp1 != NULL
	sp1->mVisited2 = true;
	}
	wpBuffer = nullptr;
	wpBufferFull = false;
	}
	}

	TEST(RefBase, RacingPromotions) {
	cpu_set_t origCpus;
	cpu_set_t myCpus;
	// Restrict us and the helper thread to disjoint cpu sets.
	// This prevents us from getting scheduled against each other,
	// which would be atrociously slow.
	if (setExclusiveCpus(&origCpus, &myCpus, &otherCpus)) {
	std::thread t(visit3AndRemove);
	std::atomic<int> deleteCount(0);
	if (sched_setaffinity(0, sizeof(cpu_set_t), &myCpus) != 0) {
	FAIL() << "setaffinity returned:" << errno;
	}
	for (int i = 0; i < NITERS; ++i) {
	Bar* bar = new Bar(&deleteCount);
	wp<Bar> wp1(bar);
	bar->mVisited1 = true;
	if (i % (NITERS / 10) == 0) {
	// Do this rarely, since it generates a log message.
	wp1 = nullptr; // No longer destroys the object.
	wp1 = bar;
	}
	wpBuffer = wp1;
	ASSERT_EQ(bar->getWeakRefs()->getWeakCount(), 2);
	wpBufferFull = true;
	// Promotion races with that in visit3AndRemove.
	// This may or may not succeed, but it shouldn't interfere with
	// the concurrent one.
	sp<Bar> sp1 = wp1.promote();
	wpWaitFor(false); // Waits for other thread to drop strong pointer.
	sp1 = nullptr;
	// No strong pointers here.
	sp1 = wp1.promote();
	ASSERT_EQ(sp1.get(), nullptr) << "Dead wp promotion succeeded!";
	}
	t.join();
	if (sched_setaffinity(0, sizeof(cpu_set_t), &origCpus) != 0) {
	FAIL();
	}
	ASSERT_EQ(NITERS, deleteCount) << "Deletions missed!";
	} // Otherwise this is slow and probably pointless on a uniprocessor.
	}