| 1 | //===----------------------------------------------------------------------===// |
|---|---|
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | // UNSUPPORTED: no-threads |
| 10 | // UNSUPPORTED: c++03, c++11 |
| 11 | |
| 12 | // <shared_mutex> |
| 13 | |
| 14 | // template <class Mutex> class shared_lock; |
| 15 | |
| 16 | // void lock(); |
| 17 | |
| 18 | #include <atomic> |
| 19 | #include <cassert> |
| 20 | #include <mutex> // std::defer_lock |
| 21 | #include <shared_mutex> |
| 22 | #include <system_error> |
| 23 | #include <thread> |
| 24 | #include <vector> |
| 25 | |
| 26 | #include "make_test_thread.h" |
| 27 | #include "test_macros.h" |
| 28 | |
| 29 | struct Monitor { |
| 30 | bool lock_shared_called = false; |
| 31 | bool unlock_shared_called = false; |
| 32 | }; |
| 33 | |
| 34 | struct TrackedMutex { |
| 35 | Monitor* monitor = nullptr; |
| 36 | |
| 37 | void lock_shared() { |
| 38 | if (monitor != nullptr) |
| 39 | monitor->lock_shared_called = true; |
| 40 | } |
| 41 | void unlock_shared() { |
| 42 | if (monitor != nullptr) |
| 43 | monitor->unlock_shared_called = true; |
| 44 | } |
| 45 | }; |
| 46 | |
| 47 | template <class Mutex> |
| 48 | void test() { |
| 49 | // Basic sanity test |
| 50 | { |
| 51 | Mutex mutex; |
| 52 | std::vector<std::thread> threads; |
| 53 | std::atomic<bool> ready(false); |
| 54 | for (int i = 0; i != 5; ++i) { |
| 55 | threads.push_back(support::make_test_thread([&] { |
| 56 | while (!ready) { |
| 57 | // spin |
| 58 | } |
| 59 | |
| 60 | std::shared_lock<Mutex> lock(mutex, std::defer_lock); |
| 61 | lock.lock(); |
| 62 | assert(lock.owns_lock()); |
| 63 | })); |
| 64 | } |
| 65 | |
| 66 | ready = true; |
| 67 | for (auto& t : threads) |
| 68 | t.join(); |
| 69 | } |
| 70 | |
| 71 | // Try locking the same shared_lock again in the same thread. This should throw an exception. |
| 72 | { |
| 73 | Mutex mutex; |
| 74 | std::shared_lock<Mutex> lock(mutex, std::defer_lock); |
| 75 | lock.lock(); |
| 76 | assert(lock.owns_lock()); |
| 77 | #ifndef TEST_HAS_NO_EXCEPTIONS |
| 78 | try { |
| 79 | lock.lock(); |
| 80 | assert(false); |
| 81 | } catch (std::system_error const& e) { |
| 82 | assert(e.code() == std::errc::resource_deadlock_would_occur); |
| 83 | } |
| 84 | #endif |
| 85 | } |
| 86 | |
| 87 | // Try locking a shared_lock that isn't associated to any mutex. This should throw an exception. |
| 88 | { |
| 89 | std::shared_lock<Mutex> lock; // no associated mutex |
| 90 | #ifndef TEST_HAS_NO_EXCEPTIONS |
| 91 | try { |
| 92 | lock.lock(); |
| 93 | assert(false); |
| 94 | } catch (std::system_error const& e) { |
| 95 | assert(e.code() == std::errc::operation_not_permitted); |
| 96 | } |
| 97 | #endif |
| 98 | } |
| 99 | } |
| 100 | |
| 101 | int main(int, char**) { |
| 102 | #if TEST_STD_VER >= 17 |
| 103 | test<std::shared_mutex>(); |
| 104 | #endif |
| 105 | test<std::shared_timed_mutex>(); |
| 106 | test<TrackedMutex>(); |
| 107 | |
| 108 | // Use shared_lock with a dummy mutex class that tracks whether each |
| 109 | // operation has been called or not. |
| 110 | { |
| 111 | Monitor monitor; |
| 112 | TrackedMutex mutex{.monitor: &monitor}; |
| 113 | |
| 114 | std::shared_lock<TrackedMutex> lock(mutex, std::defer_lock); |
| 115 | lock.lock(); |
| 116 | assert(monitor.lock_shared_called); |
| 117 | assert(lock.owns_lock()); |
| 118 | |
| 119 | lock.unlock(); |
| 120 | assert(monitor.unlock_shared_called); |
| 121 | } |
| 122 | |
| 123 | return 0; |
| 124 | } |
| 125 |