src/base/no_destructor_unittest.cc

/*
 * Copyright (C) 2019 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 <vector>

#include "perfetto/ext/base/no_destructor.h"
#include "test/gtest_and_gmock.h"

namespace perfetto {
namespace base {
namespace {

class SetFlagOnDestruct {
 public:
  SetFlagOnDestruct(bool* flag) : flag_(flag) {}
  ~SetFlagOnDestruct() { *flag_ = true; }

  bool* flag_;
};

TEST(NoDestructorTest, DoesNotDestruct) {
  bool destructor_called = false;
  { SetFlagOnDestruct f(&destructor_called); }
  ASSERT_TRUE(destructor_called);

  // Not destructed when wrapped.
  destructor_called = false;
  { NoDestructor<SetFlagOnDestruct> f(&destructor_called); }
  ASSERT_FALSE(destructor_called);
}

class NonTrivial {
 public:
  NonTrivial(std::vector<int> v, std::unique_ptr<int> p)
      : vec_(v), ptr_(std::move(p)) {}

  std::vector<int> vec_;
  std::unique_ptr<int> ptr_;
};

TEST(NoDestructorTest, ContainedObjectUsable) {
  static NoDestructor<NonTrivial> x(std::vector<int>{1, 2, 3},
                                    std::unique_ptr<int>(new int(42)));

  ASSERT_THAT(x.ref().vec_, ::testing::ElementsAre(1, 2, 3));
  ASSERT_EQ(*x.ref().ptr_, 42);

  x.ref().vec_ = {4, 5, 6};
  ASSERT_THAT(x.ref().vec_, ::testing::ElementsAre(4, 5, 6));
}

}  // namespace
}  // namespace base
}  // namespace perfetto