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- /*
- * Copyright 2018-present Facebook, Inc.
- *
- * 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 <folly/synchronization/Tearable.h>
- #include <atomic>
- #include <thread>
- #include <folly/portability/GTest.h>
- using namespace folly;
- namespace {
- struct Data {
- Data(unsigned char value) {
- setValue(value);
- }
- void setValue(unsigned char value) {
- for (auto& item : contents) {
- item = value;
- }
- }
- void checkValue(unsigned char value) {
- for (auto& item : contents) {
- ASSERT_EQ(value, item);
- }
- }
- void checkValue2(unsigned char value1, unsigned char value2) {
- for (auto& item : contents) {
- ASSERT_TRUE(item == value1 || item == value2);
- }
- }
- // Note the odd size -- this will hopefully expose layout bugs under
- // sanitizers.
- unsigned char contents[99];
- };
- static_assert(is_trivially_copyable<Data>::value, "not trivially-copyable");
- TEST(TearableTest, BasicOperations) {
- Tearable<Data> tearable;
- Data src(0);
- Data dst(1);
- for (char c = 0; c < 10; ++c) {
- src.setValue(c);
- tearable.store(src);
- tearable.load(dst);
- dst.checkValue(c);
- }
- }
- TEST(TearableTest, Races) {
- std::atomic<bool> stop(false);
- Tearable<Data> tearable(Data(1));
- std::thread write1([&]() {
- Data data0(1);
- while (!stop.load(std::memory_order_relaxed)) {
- tearable.store(data0);
- }
- });
- std::thread write2([&]() {
- Data data1(2);
- while (!stop.load(std::memory_order_relaxed)) {
- tearable.store(data1);
- }
- });
- Data val(0);
- for (int i = 0; i < 100 * 1000; ++i) {
- tearable.load(val);
- val.checkValue2(1, 2);
- }
- stop.store(true, std::memory_order_relaxed);
- write1.join();
- write2.join();
- }
- } // namespace
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