folly/test/SingletonThreadLocalTest.cpp

   1 /*
   2  * Copyright 2016-present Facebook, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *   http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #include <thread>
  18 #include <unordered_set>
  19 #include <vector>
  20
  21 #include <folly/SingletonThreadLocal.h>
  22 #include <folly/Synchronized.h>
  23 #include <folly/portability/GTest.h>
  24
  25 using namespace folly;
  26
  27 namespace {
  28 static std::atomic<std::size_t> fooCreatedCount{0};
  29 static std::atomic<std::size_t> fooDeletedCount{0};
  30 struct Foo {
  31   Foo() {
  32     ++fooCreatedCount;
  33   }
  34   ~Foo() {
  35     ++fooDeletedCount;
  36   }
  37 };
  38 using FooSingletonTL = SingletonThreadLocal<Foo>;
  39 FooSingletonTL theFooSingleton;
  40 } // namespace
  41
  42 TEST(SingletonThreadLocalTest, OneSingletonPerThread) {
  43   static constexpr std::size_t targetThreadCount{64};
  44   std::atomic<std::size_t> completedThreadCount{0};
  45   Synchronized<std::unordered_set<Foo*>> fooAddresses{};
  46   std::vector<std::thread> threads{};
  47   auto threadFunction = [&fooAddresses, &completedThreadCount] {
  48     fooAddresses.wlock()->emplace(&FooSingletonTL::get());
  49     ++completedThreadCount;
  50     while (completedThreadCount < targetThreadCount) {
  51       std::this_thread::yield();
  52     }
  53   };
  54   {
  55     for (std::size_t threadCount{0}; threadCount < targetThreadCount;
  56          ++threadCount) {
  57       threads.emplace_back(threadFunction);
  58     }
  59   }
  60   for (auto& thread : threads) {
  61     thread.join();
  62   }
  63   EXPECT_EQ(threads.size(), fooAddresses.rlock()->size());
  64   EXPECT_EQ(threads.size(), fooCreatedCount);
  65   EXPECT_EQ(threads.size(), fooDeletedCount);
  66 }