crypto/refcount_test.cc

// Copyright 2015 The BoringSSL Authors
//
// 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
//
//     https://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 "internal.h"

#include <gtest/gtest.h>

#if defined(OPENSSL_THREADS)
#include <thread>
#endif


TEST(RefCountTest, Basic) {
  CRYPTO_refcount_t count = 0;

  CRYPTO_refcount_inc(&count);
  EXPECT_EQ(1u, count.load());

  EXPECT_TRUE(CRYPTO_refcount_dec_and_test_zero(&count));
  EXPECT_EQ(0u, count.load());

  count = CRYPTO_REFCOUNT_MAX;
  CRYPTO_refcount_inc(&count);
  EXPECT_EQ(CRYPTO_REFCOUNT_MAX, count.load())
      << "Count did not saturate correctly when incrementing.";
  EXPECT_FALSE(CRYPTO_refcount_dec_and_test_zero(&count));
  EXPECT_EQ(CRYPTO_REFCOUNT_MAX, count.load())
      << "Count did not saturate correctly when decrementing.";

  count = 2;
  EXPECT_FALSE(CRYPTO_refcount_dec_and_test_zero(&count));
  EXPECT_EQ(1u, count.load());
}

#if defined(OPENSSL_THREADS)
// This test is primarily intended to run under ThreadSanitizer.
TEST(RefCountTest, Threads) {
  CRYPTO_refcount_t count = 0;

  // Race two increments.
  {
    std::thread thread([&] { CRYPTO_refcount_inc(&count); });
    CRYPTO_refcount_inc(&count);
    thread.join();
    EXPECT_EQ(2u, count.load());
  }

  // Race an increment with a decrement.
  {
    std::thread thread([&] { CRYPTO_refcount_inc(&count); });
    EXPECT_FALSE(CRYPTO_refcount_dec_and_test_zero(&count));
    thread.join();
    EXPECT_EQ(2u, count.load());
  }

  // Race two decrements.
  {
    bool thread_saw_zero;
    std::thread thread(
        [&] { thread_saw_zero = CRYPTO_refcount_dec_and_test_zero(&count); });
    bool saw_zero = CRYPTO_refcount_dec_and_test_zero(&count);
    thread.join();
    EXPECT_EQ(0u, count.load());
    // Exactly one thread should see zero.
    EXPECT_NE(saw_zero, thread_saw_zero);
  }
}
#endif