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#include <chrono>
#include <condition_variable>
#include <cstdint>
#include <future>
#include <mutex>
#include <thread>
#include <gtest/gtest.h>
#include <mega/common/lock.h>
#include <mega/common/shared_mutex.h>
namespace mega
{
namespace testing
{
// Convenience.
using Clock = std::chrono::steady_clock;
using Milliseconds = std::chrono::milliseconds;
using TimePoint = Clock::time_point;
class SharedMutexTests: public ::testing::Test
{
// Signaled when a function has completed execution.
std::condition_variable mCV;
// Serializes access to instance members.
std::mutex mLock;
// How many functions are currently being executed?
std::uint64_t mNumFunctions;
public:
SharedMutexTests():
Test(),
mCV(),
mLock(),
mNumFunctions(0)
{
}
~SharedMutexTests()
{
std::unique_lock<std::mutex> lock(mLock);
// Wait for queued functions to complete.
mCV.wait(lock, [&]() { return !mNumFunctions; });
}
// Queue a function for execution on another thread.
template<typename Ret>
std::future<Ret> execute(std::function<Ret()> function)
{
std::lock_guard<std::mutex> guard(mLock);
// Wrap the caller's function.
auto wrapper = [this](std::function<Ret()>& function) {
// Execute the caller's function.
auto result = function();
std::lock_guard<std::mutex> guard(mLock);
// Notify the fixture that the function's completed.
--mNumFunctions;
// Wake the fixture if necessary.
mCV.notify_one();
// Return result to caller.
return result;
}; // wrapper
function = std::bind(std::move(wrapper), std::move(function));
// Package the task for execution.
auto task = std::packaged_task<Ret()>(std::move(function));
// Retrieve future so the caller can wait for the function's result.
auto future = task.get_future();
// Remember that we've queued a function for execution.
++mNumFunctions;
// Spawn a thread to execute the task.
std::thread thread(std::move(task));
// Detach the thread so we can return immediately.
thread.detach();
// Return the future to the caller.
return future;
}
}; // SharedMutexTests
using namespace common;
TEST_F(SharedMutexTests, lock_fails)
{
SharedMutex mutex;
{
UniqueLock<SharedMutex> lock0(mutex, std::try_to_lock);
ASSERT_TRUE(lock0);
auto result = execute(std::function<bool()>([&]() {
return !UniqueLock<SharedMutex>(mutex, std::try_to_lock);
}));
ASSERT_TRUE(result.get());
}
SharedLock<SharedMutex> lock0(mutex, std::try_to_lock);
ASSERT_TRUE(lock0);
auto result = execute(std::function<bool()>([&]() {
return !UniqueLock<SharedMutex>(mutex, std::try_to_lock);
}));
ASSERT_TRUE(result.get());
}
TEST_F(SharedMutexTests, lock_succeeds)
{
SharedMutex mutex;
UniqueLock<SharedMutex> lock0(mutex, std::try_to_lock);
ASSERT_TRUE(lock0);
UniqueLock<SharedMutex> lock1(mutex, std::try_to_lock);
ASSERT_TRUE(lock1);
auto result = execute(std::function<TimePoint()>([&]() {
UniqueLock<SharedMutex> lock(mutex, std::defer_lock);
if (lock.try_lock_for(Milliseconds(256)))
return Clock::now();
return TimePoint::min();
}));
std::this_thread::sleep_for(Milliseconds(32));
auto released = Clock::now();
lock0.unlock();
lock1.unlock();
auto acquired = result.get();
ASSERT_GT(acquired, released);
}
TEST_F(SharedMutexTests, shared_lock_fails)
{
SharedMutex mutex;
UniqueLock<SharedMutex> lock(mutex, std::try_to_lock);
ASSERT_TRUE(lock);
auto result = execute(std::function<bool()>([&]() {
return !SharedLock<SharedMutex>(mutex, std::try_to_lock);
}));
ASSERT_TRUE(result.get());
ASSERT_FALSE(SharedLock<SharedMutex>(mutex, std::try_to_lock));
}
TEST_F(SharedMutexTests, shared_lock_recursive_succeeds)
{
SharedMutex mutex;
SharedLock<SharedMutex> lock0(mutex, std::try_to_lock);
ASSERT_TRUE(lock0);
SharedLock<SharedMutex> lock1(mutex, std::try_to_lock);
ASSERT_TRUE(lock1);
}
TEST_F(SharedMutexTests, shared_lock_succeeds)
{
SharedMutex mutex;
SharedLock<SharedMutex> lock(mutex, std::try_to_lock);
ASSERT_TRUE(lock);
auto result = execute(std::function<TimePoint()>([&]() {
SharedLock<SharedMutex> lock(mutex, std::try_to_lock);
if (lock)
return Clock::now();
return TimePoint::max();
}));
std::this_thread::sleep_for(Milliseconds(32));
auto acquired = result.get();
ASSERT_LE(acquired, Clock::now());
}
TEST_F(SharedMutexTests, to_shared_lock_succeeds)
{
SharedMutex mutex;
UniqueLock<SharedMutex> lock0(mutex, std::try_to_lock);
ASSERT_TRUE(lock0);
auto result = execute(std::function<TimePoint()>(
[&]()
{
SharedLock<SharedMutex> lock(mutex, std::defer_lock);
if (lock.try_lock_for(Milliseconds(256)))
return Clock::now();
return TimePoint::min();
}));
std::this_thread::sleep_for(Milliseconds(32));
auto released = Clock::now();
auto lock1 = lock0.to_shared_lock();
ASSERT_TRUE(lock1);
auto acquired = result.get();
ASSERT_GE(acquired, released);
lock1.unlock();
ASSERT_TRUE(lock0.try_lock());
}
} // testing
} // mega
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