| // Copyright 2020 Google LLC |
| // |
| // 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 "rwmutex.h" |
| |
| #include "gmock/gmock.h" |
| #include "gtest/gtest.h" |
| |
| #include <array> |
| #include <thread> |
| #include <vector> |
| |
| namespace { |
| constexpr const size_t NumThreads = 8; |
| } |
| |
| // Check that WLock behaves like regular mutex. |
| TEST(RWMutex, WLock) { |
| dap::RWMutex rwmutex; |
| int counter = 0; |
| |
| std::vector<std::thread> threads; |
| for (size_t i = 0; i < NumThreads; i++) { |
| threads.emplace_back([&] { |
| for (int j = 0; j < 1000; j++) { |
| dap::WLock lock(rwmutex); |
| counter++; |
| EXPECT_EQ(counter, 1); |
| counter--; |
| } |
| }); |
| } |
| |
| for (auto& thread : threads) { |
| thread.join(); |
| } |
| |
| EXPECT_EQ(counter, 0); |
| } |
| |
| TEST(RWMutex, NoRLockWithWLock) { |
| dap::RWMutex rwmutex; |
| |
| std::vector<std::thread> threads; |
| std::array<int, NumThreads> counters = {}; |
| |
| { // With WLock held... |
| dap::WLock wlock(rwmutex); |
| |
| for (size_t i = 0; i < counters.size(); i++) { |
| int* counter = &counters[i]; |
| threads.emplace_back([&rwmutex, counter] { |
| dap::RLock lock(rwmutex); |
| for (int j = 0; j < 1000; j++) { |
| (*counter)++; |
| } |
| }); |
| } |
| |
| // RLocks should block |
| for (int counter : counters) { |
| EXPECT_EQ(counter, 0); |
| } |
| } |
| |
| for (auto& thread : threads) { |
| thread.join(); |
| } |
| |
| for (int counter : counters) { |
| EXPECT_EQ(counter, 1000); |
| } |
| } |
| |
| TEST(RWMutex, NoWLockWithRLock) { |
| dap::RWMutex rwmutex; |
| |
| std::vector<std::thread> threads; |
| size_t counter = 0; |
| |
| { // With RLocks held... |
| dap::RLock rlockA(rwmutex); |
| dap::RLock rlockB(rwmutex); |
| dap::RLock rlockC(rwmutex); |
| |
| for (size_t i = 0; i < NumThreads; i++) { |
| threads.emplace_back(std::thread([&] { |
| dap::WLock lock(rwmutex); |
| counter++; |
| })); |
| } |
| |
| // ... WLocks should block |
| EXPECT_EQ(counter, 0U); |
| } |
| |
| for (auto& thread : threads) { |
| thread.join(); |
| } |
| |
| EXPECT_EQ(counter, NumThreads); |
| } |