cc/base/sidecar_list_container_unittest.cc

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/base/sidecar_list_container.h"

#include <algorithm>

#include "base/logging.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace cc {
namespace {

const size_t kNumInitiallyReservedElements = 2;
const size_t kNumElementsForTest = 100;

class DestructionNotifier {
 public:
  DestructionNotifier() : flag_(nullptr) {}
  explicit DestructionNotifier(bool* flag) { set_flag(flag); }
  ~DestructionNotifier() {
    if (flag_)
      *flag_ = true;
  }
  void set_flag(bool* flag) {
    if (flag)
      DCHECK(!*flag);
    flag_ = flag;
  }

 private:
  bool* flag_;
};

class TestElement {
 public:
  TestElement() {}
  virtual ~TestElement() {}
  void set_destruction_flag(bool* flag) { notifier_.set_flag(flag); }

 private:
  DestructionNotifier notifier_;
};

class DerivedTestElement : public TestElement {
 public:
  int additional_field = 0;
};

class TestSidecar {
 public:
  TestSidecar() {}
  explicit TestSidecar(bool* destruction_flag) : notifier_(destruction_flag) {}

  static void Destroy(void* sidecar) {
    static_cast<TestSidecar*>(sidecar)->~TestSidecar();
  }

 protected:
  virtual ~TestSidecar() {}

 private:
  DestructionNotifier notifier_;
};

class DerivedTestSidecar : public TestSidecar {
 public:
  DerivedTestSidecar() {}
  explicit DerivedTestSidecar(bool* destruction_flag)
      : TestSidecar(destruction_flag) {}
  int additional_field = 0;

 private:
  ~DerivedTestSidecar() override {}
};

class TestContainer : public SidecarListContainer<TestElement> {
 public:
  TestContainer()
      : SidecarListContainer(
            std::max(sizeof(TestElement), sizeof(DerivedTestElement)),
            std::max(sizeof(TestSidecar), sizeof(DerivedTestSidecar)),
            kNumInitiallyReservedElements,
            &TestSidecar::Destroy) {}
};

TEST(SidecarListContainerTest, Destructor) {
  bool element_destroyed = false;
  bool sidecar_destroyed = false;

  {
    TestContainer container;

    TestElement* element = container.AllocateAndConstruct<TestElement>();
    TestSidecar* sidecar =
        new (container.GetSidecar(element)) TestSidecar(&sidecar_destroyed);
    element->set_destruction_flag(&element_destroyed);

    // They shouldn't be destroyed yet. And they shouldn't overlap in memory.
    ASSERT_FALSE(element_destroyed);
    ASSERT_FALSE(sidecar_destroyed);
    ASSERT_GE(reinterpret_cast<char*>(sidecar),
              reinterpret_cast<char*>(element) + sizeof(TestElement));
  }

  // They should, however, be destroyed when going out of scope.
  ASSERT_TRUE(element_destroyed);
  ASSERT_TRUE(sidecar_destroyed);
}

TEST(SidecarListContainerTest, Clear) {
  bool element_destroyed = false;
  bool sidecar_destroyed = false;

  TestContainer container;

  TestElement* element = container.AllocateAndConstruct<TestElement>();
  new (container.GetSidecar(element)) TestSidecar(&sidecar_destroyed);
  element->set_destruction_flag(&element_destroyed);

  // They shouldn't be destroyed yet.
  ASSERT_FALSE(element_destroyed);
  ASSERT_FALSE(sidecar_destroyed);

  // They should, however, be destroyed after clearing.
  container.clear();
  EXPECT_TRUE(element_destroyed);
  EXPECT_TRUE(sidecar_destroyed);
}

TEST(SidecarListContainerTest, DerivedTypes) {
  bool element_destroyed = false;
  bool sidecar_destroyed = false;

  {
    TestContainer container;

    DerivedTestElement* element =
        container.AllocateAndConstruct<DerivedTestElement>();
    DerivedTestSidecar* sidecar = new (container.GetSidecar(element))
        DerivedTestSidecar(&sidecar_destroyed);
    element->set_destruction_flag(&element_destroyed);
    element->additional_field = 12;
    sidecar->additional_field = 13;

    // They shouldn't be destroyed yet.
    ASSERT_FALSE(element_destroyed);
    ASSERT_FALSE(sidecar_destroyed);
  }

  // They should, however, be destroyed when going out of scope.
  EXPECT_TRUE(element_destroyed);
  EXPECT_TRUE(sidecar_destroyed);
}

TEST(SidecarListContainerTest, AddingAndRemovingElements) {
  TestContainer container;
  EXPECT_TRUE(container.empty());
  EXPECT_EQ(0u, container.size());
  EXPECT_EQ(container.end(), container.begin());

  for (size_t i = 1; i <= kNumElementsForTest; i++) {
    TestElement* element = container.AllocateAndConstruct<TestElement>();
    new (container.GetSidecar(element)) TestSidecar();

    ASSERT_FALSE(container.empty());
    ASSERT_EQ(i, container.size());
    ASSERT_NE(container.end(), container.begin());
  }

  size_t num_elements = 0;
  for (const auto* element : container) {
    (void)element;
    num_elements++;
  }
  EXPECT_EQ(kNumElementsForTest, num_elements);

  container.clear();
  EXPECT_TRUE(container.empty());
  EXPECT_EQ(0u, container.size());
  EXPECT_EQ(container.end(), container.begin());
}

TEST(SidecarListContainerTest, RemoveLast) {
  // We need only ensure that the sidecar is also destroyed on RemoveLast.
  // The rest is logic already present in ListContainer.
  bool sidecar_destroyed = false;
  TestContainer container;
  TestElement* element = container.AllocateAndConstruct<TestElement>();
  new (container.GetSidecar(element)) TestSidecar(&sidecar_destroyed);
  ASSERT_FALSE(sidecar_destroyed);
  container.RemoveLast();
  ASSERT_TRUE(sidecar_destroyed);
}

}  // namespace
}  // namespace cc