sky/engine/platform/PurgeableVectorTest.cpp - external/github.com/flutter/engine - Git at Google

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "sky/engine/platform/PurgeableVector.h"

 #include "sky/engine/platform/TestingPlatformSupport.h"
 #include "sky/engine/public/platform/WebDiscardableMemory.h"
 #include "sky/engine/wtf/Vector.h"

 #include <algorithm>
 #include <cstdlib>

 #include <gtest/gtest.h>

 using namespace blink;

 namespace {

 const size_t kTestSize = 32 * 1024;

 enum DiscardableMemorySupport {
     DontSupportDiscardableMemory,
     SupportDiscardableMemory,
 };

 class PurgeableVectorTestWithPlatformSupport : public testing::TestWithParam<DiscardableMemorySupport> {
 public:
     PurgeableVectorTestWithPlatformSupport() : m_testingPlatformSupport(makeTestingPlatformSupportConfig()) { }

 protected:
     bool isDiscardableMemorySupported() const { return GetParam() == SupportDiscardableMemory; }

     TestingPlatformSupport::Config makeTestingPlatformSupportConfig() const
     {
         TestingPlatformSupport::Config config;
         config.hasDiscardableMemorySupport = isDiscardableMemorySupported();
         return config;
     }

     PurgeableVector::PurgeableOption makePurgeableOption() const
     {
         return isDiscardableMemorySupported() ? PurgeableVector::Purgeable : PurgeableVector::NotPurgeable;
     }

 private:
     TestingPlatformSupport m_testingPlatformSupport;
 };

 TEST_P(PurgeableVectorTestWithPlatformSupport, grow)
 {
     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.grow(kTestSize);
     ASSERT_EQ(kTestSize, purgeableVector.size());
     // Make sure the underlying buffer was actually (re)allocated.
     memset(purgeableVector.data(), 0, purgeableVector.size());
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, clear)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.append(testData.data(), testData.size());
     EXPECT_EQ(testData.size(), purgeableVector.size());

     purgeableVector.clear();
     EXPECT_EQ(0U, purgeableVector.size());
     EXPECT_EQ(0, purgeableVector.data());
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, clearDoesNotResetLockCounter)
 {
     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.clear();
     EXPECT_TRUE(purgeableVector.isLocked());
     purgeableVector.unlock();
     EXPECT_FALSE(purgeableVector.isLocked());
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, reserveCapacityDoesNotChangeSize)
 {
     PurgeableVector purgeableVector(makePurgeableOption());
     EXPECT_EQ(0U, purgeableVector.size());
     purgeableVector.reserveCapacity(kTestSize);
     EXPECT_EQ(0U, purgeableVector.size());
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, multipleAppends)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(makePurgeableOption());
     // Force an allocation.
     const char kSmallString[] = "hello";
     purgeableVector.append(kSmallString, sizeof(kSmallString));
     const char* const data = purgeableVector.data();

     // Append all the testing data in 4 iterations. The |data| pointer should
     // have been changed at the end of the unit test due to reallocations.
     const size_t kIterationCount = 4;
     ASSERT_EQ(0U, testData.size() % kIterationCount);
     for (size_t i = 0; i < kIterationCount; ++i) {
         const char* const testDataStart = testData.data() + i * (testData.size() / kIterationCount);
         purgeableVector.append(testDataStart, testData.size() / kIterationCount);
         ASSERT_EQ((i + 1) * testData.size() / kIterationCount, purgeableVector.size() - sizeof(kSmallString));
     }

     ASSERT_EQ(sizeof(kSmallString) + testData.size(), purgeableVector.size());
     EXPECT_NE(data, purgeableVector.data());
     EXPECT_EQ(0, memcmp(purgeableVector.data() + sizeof(kSmallString), testData.data(), testData.size()));
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, multipleAppendsAfterReserveCapacity)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.reserveCapacity(testData.size());
     const char* const data = purgeableVector.data();

     // The |data| pointer should be unchanged at the end of the unit test
     // meaning that there should not have been any reallocation.
     const size_t kIterationCount = 4;
     ASSERT_EQ(0U, testData.size() % kIterationCount);
     for (size_t i = 0; i < kIterationCount; ++i) {
         const char* const testDataStart = testData.data() + i * (testData.size() / kIterationCount);
         purgeableVector.append(testDataStart, testData.size() / kIterationCount);
         ASSERT_EQ((i + 1) * testData.size() / kIterationCount, purgeableVector.size());
     }

     ASSERT_EQ(testData.size(), purgeableVector.size());
     EXPECT_EQ(data, purgeableVector.data());
     EXPECT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, reserveCapacityUsesExactCapacityWhenVectorIsEmpty)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.reserveCapacity(kTestSize);
     const char* const data = purgeableVector.data();

     purgeableVector.append(testData.data(), testData.size());
     EXPECT_EQ(data, purgeableVector.data());
     EXPECT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));

     // This test is not reliable if the PurgeableVector uses a plain WTF::Vector
     // for storage, as it does if discardable memory is not supported; the vectors
     // capacity will always be expanded to fill the PartitionAlloc bucket.
     if (isDiscardableMemorySupported()) {
         // Appending one extra byte should cause a reallocation since the first
         // allocation happened while the purgeable vector was empty. This behavior
         // helps us guarantee that there is no memory waste on very small vectors
         // (which SharedBuffer requires).
         purgeableVector.append(testData.data(), 1);
         EXPECT_NE(data, purgeableVector.data());
     }
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, appendReservesCapacityIfNeeded)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(makePurgeableOption());
     // No reserveCapacity().
     ASSERT_FALSE(purgeableVector.data());

     purgeableVector.append(testData.data(), testData.size());
     ASSERT_EQ(testData.size(), purgeableVector.size());
     ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, adopt)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);
     const Vector<char> testDataCopy(testData);
     const char* const testDataPtr = testData.data();

     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.adopt(testData);
     EXPECT_TRUE(testData.isEmpty());
     EXPECT_EQ(kTestSize, purgeableVector.size());
     ASSERT_EQ(0, memcmp(purgeableVector.data(), testDataCopy.data(), testDataCopy.size()));

     if (isDiscardableMemorySupported()) {
         // An extra discardable memory allocation + memcpy() should have happened.
         EXPECT_NE(testDataPtr, purgeableVector.data());
     } else {
         // Vector::swap() should have been used.
         EXPECT_EQ(testDataPtr, purgeableVector.data());
     }
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, adoptEmptyVector)
 {
     Vector<char> testData;
     PurgeableVector purgeableVector(makePurgeableOption());
     purgeableVector.adopt(testData);
 }

 TEST(PurgeableVectorTestWithPlatformSupport, adoptDiscardsPreviousData)
 {
     Vector<char> testData;
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(PurgeableVector::NotPurgeable);
     static const char smallString[] = "hello";
     purgeableVector.append(smallString, sizeof(smallString));
     ASSERT_EQ(0, memcmp(purgeableVector.data(), smallString, sizeof(smallString)));

     purgeableVector.adopt(testData);
     EXPECT_EQ(testData.size(), purgeableVector.size());
     ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, unlockWithoutHintAtConstruction)
 {
     Vector<char> testData(30000);
     std::generate(testData.begin(), testData.end(), &std::rand);

     unsigned length = testData.size();
     PurgeableVector purgeableVector(PurgeableVector::NotPurgeable);
     purgeableVector.append(testData.data(), length);
     ASSERT_EQ(length, purgeableVector.size());
     const char* data = purgeableVector.data();

     purgeableVector.unlock();

     // Note that the purgeable vector must be locked before calling data().
     const bool wasPurged = !purgeableVector.lock();
     if (isDiscardableMemorySupported()) {
         // The implementation of purgeable memory used for testing always purges data upon unlock().
         EXPECT_TRUE(wasPurged);
     }

     if (isDiscardableMemorySupported()) {
         // The data should have been moved from the heap-allocated vector to a purgeable buffer.
         ASSERT_NE(data, purgeableVector.data());
     } else {
         ASSERT_EQ(data, purgeableVector.data());
     }

     if (!wasPurged)
         ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), length));
 }

 TEST(PurgeableVectorTest, unlockOnEmptyPurgeableVector)
 {
     PurgeableVector purgeableVector;
     ASSERT_EQ(0U, purgeableVector.size());
     purgeableVector.unlock();
     ASSERT_FALSE(purgeableVector.isLocked());
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, unlockOnPurgeableVectorWithPurgeableHint)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector;
     purgeableVector.append(testData.data(), kTestSize);
     const char* const data = purgeableVector.data();

     // unlock() should happen in place, i.e. without causing any reallocation.
     // Note that the instance must be locked when data() is called.
     purgeableVector.unlock();
     EXPECT_FALSE(purgeableVector.isLocked());
     purgeableVector.lock();
     EXPECT_TRUE(purgeableVector.isLocked());
     EXPECT_EQ(data, purgeableVector.data());
 }

 TEST_P(PurgeableVectorTestWithPlatformSupport, lockingUsesACounter)
 {
     Vector<char> testData(kTestSize);
     std::generate(testData.begin(), testData.end(), &std::rand);

     PurgeableVector purgeableVector(PurgeableVector::NotPurgeable);
     purgeableVector.append(testData.data(), testData.size());
     ASSERT_EQ(testData.size(), purgeableVector.size());

     ASSERT_TRUE(purgeableVector.isLocked()); // SharedBuffer is locked at creation.
     ASSERT_TRUE(purgeableVector.lock()); // Add an extra lock.
     ASSERT_TRUE(purgeableVector.isLocked());

     purgeableVector.unlock();
     ASSERT_TRUE(purgeableVector.isLocked());

     purgeableVector.unlock();
     ASSERT_FALSE(purgeableVector.isLocked());

     if (purgeableVector.lock())
         ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
 }

 // Instantiates all the unit tests using the SharedBufferTestWithPlatformSupport fixture both with
 // and without discardable memory support.
 INSTANTIATE_TEST_CASE_P(testsWithPlatformSetUp, PurgeableVectorTestWithPlatformSupport,
     ::testing::Values(DontSupportDiscardableMemory, SupportDiscardableMemory));

 } // namespace
	/*
	* Copyright (C) 2014 Google Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "sky/engine/platform/PurgeableVector.h"

	#include "sky/engine/platform/TestingPlatformSupport.h"
	#include "sky/engine/public/platform/WebDiscardableMemory.h"
	#include "sky/engine/wtf/Vector.h"

	#include <algorithm>
	#include <cstdlib>

	#include <gtest/gtest.h>

	using namespace blink;

	namespace {

	const size_t kTestSize = 32 * 1024;

	enum DiscardableMemorySupport {
	DontSupportDiscardableMemory,
	SupportDiscardableMemory,
	};

	class PurgeableVectorTestWithPlatformSupport : public testing::TestWithParam<DiscardableMemorySupport> {
	public:
	PurgeableVectorTestWithPlatformSupport() : m_testingPlatformSupport(makeTestingPlatformSupportConfig()) { }

	protected:
	bool isDiscardableMemorySupported() const { return GetParam() == SupportDiscardableMemory; }

	TestingPlatformSupport::Config makeTestingPlatformSupportConfig() const
	{
	TestingPlatformSupport::Config config;
	config.hasDiscardableMemorySupport = isDiscardableMemorySupported();
	return config;
	}

	PurgeableVector::PurgeableOption makePurgeableOption() const
	{
	return isDiscardableMemorySupported() ? PurgeableVector::Purgeable : PurgeableVector::NotPurgeable;
	}

	private:
	TestingPlatformSupport m_testingPlatformSupport;
	};

	TEST_P(PurgeableVectorTestWithPlatformSupport, grow)
	{
	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.grow(kTestSize);
	ASSERT_EQ(kTestSize, purgeableVector.size());
	// Make sure the underlying buffer was actually (re)allocated.
	memset(purgeableVector.data(), 0, purgeableVector.size());
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, clear)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.append(testData.data(), testData.size());
	EXPECT_EQ(testData.size(), purgeableVector.size());

	purgeableVector.clear();
	EXPECT_EQ(0U, purgeableVector.size());
	EXPECT_EQ(0, purgeableVector.data());
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, clearDoesNotResetLockCounter)
	{
	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.clear();
	EXPECT_TRUE(purgeableVector.isLocked());
	purgeableVector.unlock();
	EXPECT_FALSE(purgeableVector.isLocked());
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, reserveCapacityDoesNotChangeSize)
	{
	PurgeableVector purgeableVector(makePurgeableOption());
	EXPECT_EQ(0U, purgeableVector.size());
	purgeableVector.reserveCapacity(kTestSize);
	EXPECT_EQ(0U, purgeableVector.size());
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, multipleAppends)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(makePurgeableOption());
	// Force an allocation.
	const char kSmallString[] = "hello";
	purgeableVector.append(kSmallString, sizeof(kSmallString));
	const char* const data = purgeableVector.data();

	// Append all the testing data in 4 iterations. The \|data\| pointer should
	// have been changed at the end of the unit test due to reallocations.
	const size_t kIterationCount = 4;
	ASSERT_EQ(0U, testData.size() % kIterationCount);
	for (size_t i = 0; i < kIterationCount; ++i) {
	const char* const testDataStart = testData.data() + i * (testData.size() / kIterationCount);
	purgeableVector.append(testDataStart, testData.size() / kIterationCount);
	ASSERT_EQ((i + 1) * testData.size() / kIterationCount, purgeableVector.size() - sizeof(kSmallString));
	}

	ASSERT_EQ(sizeof(kSmallString) + testData.size(), purgeableVector.size());
	EXPECT_NE(data, purgeableVector.data());
	EXPECT_EQ(0, memcmp(purgeableVector.data() + sizeof(kSmallString), testData.data(), testData.size()));
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, multipleAppendsAfterReserveCapacity)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.reserveCapacity(testData.size());
	const char* const data = purgeableVector.data();

	// The \|data\| pointer should be unchanged at the end of the unit test
	// meaning that there should not have been any reallocation.
	const size_t kIterationCount = 4;
	ASSERT_EQ(0U, testData.size() % kIterationCount);
	for (size_t i = 0; i < kIterationCount; ++i) {
	const char* const testDataStart = testData.data() + i * (testData.size() / kIterationCount);
	purgeableVector.append(testDataStart, testData.size() / kIterationCount);
	ASSERT_EQ((i + 1) * testData.size() / kIterationCount, purgeableVector.size());
	}

	ASSERT_EQ(testData.size(), purgeableVector.size());
	EXPECT_EQ(data, purgeableVector.data());
	EXPECT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, reserveCapacityUsesExactCapacityWhenVectorIsEmpty)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.reserveCapacity(kTestSize);
	const char* const data = purgeableVector.data();

	purgeableVector.append(testData.data(), testData.size());
	EXPECT_EQ(data, purgeableVector.data());
	EXPECT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));

	// This test is not reliable if the PurgeableVector uses a plain WTF::Vector
	// for storage, as it does if discardable memory is not supported; the vectors
	// capacity will always be expanded to fill the PartitionAlloc bucket.
	if (isDiscardableMemorySupported()) {
	// Appending one extra byte should cause a reallocation since the first
	// allocation happened while the purgeable vector was empty. This behavior
	// helps us guarantee that there is no memory waste on very small vectors
	// (which SharedBuffer requires).
	purgeableVector.append(testData.data(), 1);
	EXPECT_NE(data, purgeableVector.data());
	}
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, appendReservesCapacityIfNeeded)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(makePurgeableOption());
	// No reserveCapacity().
	ASSERT_FALSE(purgeableVector.data());

	purgeableVector.append(testData.data(), testData.size());
	ASSERT_EQ(testData.size(), purgeableVector.size());
	ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, adopt)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);
	const Vector<char> testDataCopy(testData);
	const char* const testDataPtr = testData.data();

	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.adopt(testData);
	EXPECT_TRUE(testData.isEmpty());
	EXPECT_EQ(kTestSize, purgeableVector.size());
	ASSERT_EQ(0, memcmp(purgeableVector.data(), testDataCopy.data(), testDataCopy.size()));

	if (isDiscardableMemorySupported()) {
	// An extra discardable memory allocation + memcpy() should have happened.
	EXPECT_NE(testDataPtr, purgeableVector.data());
	} else {
	// Vector::swap() should have been used.
	EXPECT_EQ(testDataPtr, purgeableVector.data());
	}
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, adoptEmptyVector)
	{
	Vector<char> testData;
	PurgeableVector purgeableVector(makePurgeableOption());
	purgeableVector.adopt(testData);
	}

	TEST(PurgeableVectorTestWithPlatformSupport, adoptDiscardsPreviousData)
	{
	Vector<char> testData;
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(PurgeableVector::NotPurgeable);
	static const char smallString[] = "hello";
	purgeableVector.append(smallString, sizeof(smallString));
	ASSERT_EQ(0, memcmp(purgeableVector.data(), smallString, sizeof(smallString)));

	purgeableVector.adopt(testData);
	EXPECT_EQ(testData.size(), purgeableVector.size());
	ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, unlockWithoutHintAtConstruction)
	{
	Vector<char> testData(30000);
	std::generate(testData.begin(), testData.end(), &std::rand);

	unsigned length = testData.size();
	PurgeableVector purgeableVector(PurgeableVector::NotPurgeable);
	purgeableVector.append(testData.data(), length);
	ASSERT_EQ(length, purgeableVector.size());
	const char* data = purgeableVector.data();

	purgeableVector.unlock();

	// Note that the purgeable vector must be locked before calling data().
	const bool wasPurged = !purgeableVector.lock();
	if (isDiscardableMemorySupported()) {
	// The implementation of purgeable memory used for testing always purges data upon unlock().
	EXPECT_TRUE(wasPurged);
	}

	if (isDiscardableMemorySupported()) {
	// The data should have been moved from the heap-allocated vector to a purgeable buffer.
	ASSERT_NE(data, purgeableVector.data());
	} else {
	ASSERT_EQ(data, purgeableVector.data());
	}

	if (!wasPurged)
	ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), length));
	}

	TEST(PurgeableVectorTest, unlockOnEmptyPurgeableVector)
	{
	PurgeableVector purgeableVector;
	ASSERT_EQ(0U, purgeableVector.size());
	purgeableVector.unlock();
	ASSERT_FALSE(purgeableVector.isLocked());
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, unlockOnPurgeableVectorWithPurgeableHint)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector;
	purgeableVector.append(testData.data(), kTestSize);
	const char* const data = purgeableVector.data();

	// unlock() should happen in place, i.e. without causing any reallocation.
	// Note that the instance must be locked when data() is called.
	purgeableVector.unlock();
	EXPECT_FALSE(purgeableVector.isLocked());
	purgeableVector.lock();
	EXPECT_TRUE(purgeableVector.isLocked());
	EXPECT_EQ(data, purgeableVector.data());
	}

	TEST_P(PurgeableVectorTestWithPlatformSupport, lockingUsesACounter)
	{
	Vector<char> testData(kTestSize);
	std::generate(testData.begin(), testData.end(), &std::rand);

	PurgeableVector purgeableVector(PurgeableVector::NotPurgeable);
	purgeableVector.append(testData.data(), testData.size());
	ASSERT_EQ(testData.size(), purgeableVector.size());

	ASSERT_TRUE(purgeableVector.isLocked()); // SharedBuffer is locked at creation.
	ASSERT_TRUE(purgeableVector.lock()); // Add an extra lock.
	ASSERT_TRUE(purgeableVector.isLocked());

	purgeableVector.unlock();
	ASSERT_TRUE(purgeableVector.isLocked());

	purgeableVector.unlock();
	ASSERT_FALSE(purgeableVector.isLocked());

	if (purgeableVector.lock())
	ASSERT_EQ(0, memcmp(purgeableVector.data(), testData.data(), testData.size()));
	}

	// Instantiates all the unit tests using the SharedBufferTestWithPlatformSupport fixture both with
	// and without discardable memory support.
	INSTANTIATE_TEST_CASE_P(testsWithPlatformSetUp, PurgeableVectorTestWithPlatformSupport,
	::testing::Values(DontSupportDiscardableMemory, SupportDiscardableMemory));

	} // namespace