// SPDX-License-Identifier: BSD-3-Clause
/* Copyright 2016-2020, Intel Corporation */

/*
 * obj_cpp_mutex.cpp -- cpp mutex test
 */

#include "unittest.hpp"

#include <libpmemobj++/persistent_ptr.hpp>
#include <libpmemobj++/pool.hpp>
#include <libpmemobj++/timed_mutex.hpp>
#include <libpmemobj/atomic_base.h>

#include <mutex>
#include <thread>

#define LAYOUT "cpp"

namespace nvobj = pmem::obj;

namespace
{

/* pool root structure */
struct root {
	nvobj::timed_mutex pmutex;
	unsigned counter;
};

/* number of ops per thread */
const unsigned num_ops = 200;

/* the number of threads */
const unsigned num_threads = 30;

/* timeout for try_lock_for and try_lock_until methods */
const auto timeout = std::chrono::milliseconds(100);

/* loop trylock_for|until tests */
bool loop;

/*
 * Premature wake-up tolerance.
 * XXX Windows - this needs to be investigated, it shouldn't timeout this long
 * before the actual timeout.
 */
const auto epsilon = std::chrono::milliseconds(16);

/*
 * increment_pint -- (internal) test the mutex with an std::lock_guard
 */
static void
increment_pint(nvobj::persistent_ptr<root> proot)
{
	for (unsigned i = 0; i < num_ops; ++i) {
		std::lock_guard<nvobj::timed_mutex> lock(proot->pmutex);
		(proot->counter)++;
	}
}

/*
 * decrement_pint -- (internal) test the mutex with an std::unique_lock
 */
static void
decrement_pint(nvobj::persistent_ptr<root> proot)
{
	std::unique_lock<nvobj::timed_mutex> lock(proot->pmutex);
	for (unsigned i = 0; i < num_ops; ++i)
		--(proot->counter);

	lock.unlock();
}

/*
 * trylock_test -- (internal) test the trylock implementation
 */
static void
trylock_test(nvobj::persistent_ptr<root> proot)
{
	for (;;) {
		if (proot->pmutex.try_lock()) {
			(proot->counter)++;
			proot->pmutex.unlock();
			return;
		}
	}
}

/*
 * trylock_for_test -- (internal) test the try_lock_for implementation
 */
static void
trylock_for_test(nvobj::persistent_ptr<root> proot)
{
	using clk = std::chrono::system_clock;

	do {
		auto t1 = clk::now();
		if (proot->pmutex.try_lock_for(timeout)) {
			(proot->counter)++;
			proot->pmutex.unlock();
			break;
		} else {
			auto t2 = clk::now();
			auto diff = std::chrono::duration_cast<
				std::chrono::milliseconds>((t1 + timeout) - t2);
			UT_ASSERT(diff < epsilon);
		}
	} while (loop);
	return;
}

/*
 * trylock_until_test -- (internal) test the try_lock_until implementation
 */
static void
trylock_until_test(nvobj::persistent_ptr<root> proot)
{
	using clk = std::chrono::system_clock;

	do {
		auto t1 = clk::now();
		if (proot->pmutex.try_lock_until(t1 + timeout)) {
			--(proot->counter);
			proot->pmutex.unlock();
			break;
		} else {
			auto t2 = clk::now();
			auto diff = std::chrono::duration_cast<
				std::chrono::milliseconds>((t1 + timeout) - t2);
			UT_ASSERT(diff < epsilon);
		}
	} while (loop);

	return;
}

/*
 * mutex_zero_test -- (internal) test the zeroing constructor
 */
void
mutex_zero_test(nvobj::pool<struct root> &pop)
{
	PMEMoid raw_mutex;

	pmemobj_alloc(
		pop.handle(), &raw_mutex, sizeof(PMEMmutex), 1,
		[](PMEMobjpool *pop, void *ptr, void *) -> int {
			PMEMmutex *mtx = static_cast<PMEMmutex *>(ptr);
			pmemobj_memset_persist(pop, mtx, 1, sizeof(*mtx));
			return 0;
		},
		nullptr);

	nvobj::timed_mutex *placed_mtx =
		new (pmemobj_direct(raw_mutex)) nvobj::timed_mutex;
	std::unique_lock<nvobj::timed_mutex> lck(*placed_mtx);
}

/*
 * mutex_test -- (internal) launch worker threads to test the pmutex
 */
template <typename Worker>
void
timed_mtx_test(nvobj::pool<root> &pop, const Worker &function)
{
	std::thread threads[num_threads];

	auto proot = pop.root();

	for (unsigned i = 0; i < num_threads; ++i)
		threads[i] = std::thread(function, proot);

	for (unsigned i = 0; i < num_threads; ++i)
		threads[i].join();
}

void
test_stack()
{
	/* mutex is not allowed outside of pmem */
	try {
		nvobj::timed_mutex stack_mutex;
		UT_ASSERT(0);
	} catch (pmem::lock_error &le) {
	} catch (...) {
		UT_ASSERT(0);
	}
}

void
test_error_handling(nvobj::pool<root> &pop)
{
	nvobj::persistent_ptr<root> proot = pop.root();

	proot->pmutex.lock();

	/* try_locking already taken lock fails with false */
	UT_ASSERT(proot->pmutex.try_lock() == false);

	proot->pmutex.unlock();
}
}

static void
test(int argc, char *argv[])
{
	if (argc != 2)
		UT_FATAL("usage: %s file-name", argv[0]);

	const char *path = argv[1];

	nvobj::pool<root> pop;

	try {
		pop = nvobj::pool<root>::create(path, LAYOUT, PMEMOBJ_MIN_POOL,
						S_IWUSR | S_IRUSR);
	} catch (pmem::pool_error &pe) {
		UT_FATAL("!pool::create: %s %s", pe.what(), path);
	}

	mutex_zero_test(pop);

	timed_mtx_test(pop, increment_pint);
	UT_ASSERTeq(pop.root()->counter, num_threads * num_ops);

	timed_mtx_test(pop, decrement_pint);
	UT_ASSERTeq(pop.root()->counter, 0);

	timed_mtx_test(pop, trylock_test);
	UT_ASSERTeq(pop.root()->counter, num_threads);

	/* loop the next two tests */
	loop = true;

	timed_mtx_test(pop, trylock_until_test);
	UT_ASSERTeq(pop.root()->counter, 0);

	timed_mtx_test(pop, trylock_for_test);
	UT_ASSERTeq(pop.root()->counter, num_threads);

	loop = false;

	pop.root()->pmutex.lock();

	timed_mtx_test(pop, trylock_until_test);
	UT_ASSERTeq(pop.root()->counter, num_threads);

	timed_mtx_test(pop, trylock_for_test);
	UT_ASSERTeq(pop.root()->counter, num_threads);

	pop.root()->pmutex.unlock();

	/* pmemcheck related persist */
	pmemobj_persist(pop.handle(), &(pop.root()->counter),
			sizeof(pop.root()->counter));

	test_stack();
	test_error_handling(pop);

	pop.close();
}

int
main(int argc, char *argv[])
{
	return run_test([&] { test(argc, argv); });
}
