flutter_flutter/sky/engine/platform/PurgeableVectorTest.cpp

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

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