UnrealEngineUWP/Engine/Source/Programs/AutoRTFMTests/Private/Open.cpp

// Copyright Epic Games, Inc. All Rights Reserved.

#include "Catch2Includes.h"
#include <AutoRTFM/AutoRTFM.h>
#include <atomic>
#include <map>
#include <vector>

TEST_CASE("Open")
{
    bool bDidRun = false;
    REQUIRE(
        AutoRTFM::ETransactionResult::Committed ==
        AutoRTFM::Transact([&] ()
        {
            AutoRTFM::Open([&] () { bDidRun = true; });
            AutoRTFM::Open([&] () { REQUIRE(bDidRun); });
        }));
    REQUIRE(bDidRun);
}

TEST_CASE("Open.Large")
{
    int x = 42;
    std::vector<int> v;
    std::map<int, std::vector<int>> m;
    bool bRanOpen = false;
    v.push_back(100);
    m[1].push_back(2);
    m[1].push_back(3);
    m[4].push_back(5);
    m[6].push_back(7);
    m[6].push_back(8);
    m[6].push_back(9);
    REQUIRE(
        AutoRTFM::ETransactionResult::Committed ==
        AutoRTFM::Transact([&] () {
            x = 5;

            for (size_t n = 10; n--;)
            {
                v.push_back(2 * n);
            }

            m.clear();
            m[10].push_back(11);
            m[12].push_back(13);
            m[12].push_back(14);

            AutoRTFM::Open([&] () {
#if 0
                // These checks are UB, because the open is interacting with transactional data!
                REQUIRE(x == 42);
                REQUIRE(v.size() == 1);
                REQUIRE(v[0] == 100);
                REQUIRE(m.size() == 3);
                REQUIRE(m[1].size() == 2);
                REQUIRE(m[1][0] == 2);
                REQUIRE(m[1][1] == 3);
                REQUIRE(m[4].size() == 1);
                REQUIRE(m[4][0] == 5);
                REQUIRE(m[6].size() == 3);
                REQUIRE(m[6][0] == 7);
                REQUIRE(m[6][1] == 8);
                REQUIRE(m[6][2] == 9);
#endif
                bRanOpen = true;
            });
        }));
    
    REQUIRE(bRanOpen);
    REQUIRE(x == 5);
    REQUIRE(v.size() == 11);
    REQUIRE(v[0] == 100);
    REQUIRE(v[1] == 18);
    REQUIRE(v[2] == 16);
    REQUIRE(v[3] == 14);
    REQUIRE(v[4] == 12);
    REQUIRE(v[5] == 10);
    REQUIRE(v[6] == 8);
    REQUIRE(v[7] == 6);
    REQUIRE(v[8] == 4);
    REQUIRE(v[9] == 2);
    REQUIRE(v[10] == 0);
    REQUIRE(m.size() == 2);
    REQUIRE(m[10].size() == 1);
    REQUIRE(m[10][0] == 11);
    REQUIRE(m[12].size() == 2);
    REQUIRE(m[12][0] == 13);
    REQUIRE(m[12][1] == 14);
}

TEST_CASE("Open.Atomics")
{
    std::atomic<bool> bDidRun = false;
    REQUIRE(
        AutoRTFM::ETransactionResult::Committed ==
        AutoRTFM::Transact([&] ()
        {
            AutoRTFM::Open([&] () { bDidRun = true; });
            AutoRTFM::Open([&] () { REQUIRE(bDidRun); });
        }));
    REQUIRE(bDidRun);
}

TEST_CASE("Open.ReturnValue")
{
    static_assert(AutoRTFM::IsSafeToReturnFromOpen<int>);
    static_assert(AutoRTFM::IsSafeToReturnFromOpen<float>);
    static_assert(AutoRTFM::IsSafeToReturnFromOpen<int*>);
    static_assert(AutoRTFM::IsSafeToReturnFromOpen<void>);
    static_assert(AutoRTFM::IsSafeToReturnFromOpen<std::tuple<int, float>>);
    static_assert(!AutoRTFM::IsSafeToReturnFromOpen<std::string>);
    static_assert(!AutoRTFM::IsSafeToReturnFromOpen<std::tuple<int, std::string>>);

    SECTION("int")
    {
        int Value = 10;
        AutoRTFM::ETransactionResult Result = AutoRTFM::Transact([&] ()
            {
                int Got = AutoRTFM::Open([] { return 42; });
                AutoRTFM::Open([&] { Value = Got; });
            });
        REQUIRE(AutoRTFM::ETransactionResult::Committed == Result);
        REQUIRE(42 == Value);
    }

    SECTION("char*")
    {
        std::string Value = "<unassigned>";
        AutoRTFM::ETransactionResult Result = AutoRTFM::Transact([&] ()
            {
                // Note: AutoRTFM::Open() is returning a const char*
                std::string Got = AutoRTFM::Open([] { return "meow"; });
                AutoRTFM::Open([&] { Value = Got; });
            });
        REQUIRE(AutoRTFM::ETransactionResult::Committed == Result);
        REQUIRE("meow" == Value);
    }
    
    SECTION("tuple")
    {
        int Int = 0;
        std::string String = "<unassigned>";
        AutoRTFM::ETransactionResult Result = AutoRTFM::Transact([&] ()
            {
                auto [I, S] = AutoRTFM::Open([] 
                    { 
                        return std::make_tuple(42, "woof"); 
                    });
                AutoRTFM::Open([&]
                    { 
                        Int = I; 
                        String = S; 
                    });
            });
        REQUIRE(AutoRTFM::ETransactionResult::Committed == Result);
        REQUIRE(42 == Int);
        REQUIRE("woof" == String);
    }

    SECTION("Custom type")
    {
        SECTION("AutoRTFMAssignFromOpenToClosed() by value")
        {
            struct FMyStruct
            {
                int Value = 0;
                static void AutoRTFMAssignFromOpenToClosed(FMyStruct& Closed, FMyStruct Open)
                {
                    Closed.Value = Open.Value;
                }
            };
            static_assert(AutoRTFM::IsSafeToReturnFromOpen<FMyStruct>);

            FMyStruct StructResult;
            AutoRTFM::ETransactionResult TransactionResult = AutoRTFM::Transact([&]
            {
                FMyStruct Closed = AutoRTFM::Open([] { return FMyStruct{42}; });
                AutoRTFM::Open([&] { StructResult = Closed; });
            });
            REQUIRE(AutoRTFM::ETransactionResult::Committed == TransactionResult);
            REQUIRE(42 == StructResult.Value);
        }
        SECTION("AutoRTFMAssignFromOpenToClosed() by const-ref")
        {
            struct FMyStruct
            {
                int Value = 0;
                static void AutoRTFMAssignFromOpenToClosed(FMyStruct& Closed, const FMyStruct& Open)
                {
                    Closed.Value = Open.Value;
                }
            };
            static_assert(AutoRTFM::IsSafeToReturnFromOpen<FMyStruct>);

            FMyStruct StructResult;
            AutoRTFM::ETransactionResult TransactionResult = AutoRTFM::Transact([&]
            {
                FMyStruct Closed = AutoRTFM::Open([] { return FMyStruct{42}; });
                AutoRTFM::Open([&] { StructResult = Closed; });
            });
            REQUIRE(AutoRTFM::ETransactionResult::Committed == TransactionResult);
            REQUIRE(42 == StructResult.Value);
        }
        SECTION("AutoRTFMAssignFromOpenToClosed() by rvalue-ref")
        {
            struct FMyStruct
            {
                int Value = 0;
                bool* WasMoved = nullptr;
                static void AutoRTFMAssignFromOpenToClosed(FMyStruct& Closed, FMyStruct&& Open)
                {
                    Closed.Value = Open.Value;
                    *Open.WasMoved = true;
                }
            };
            static_assert(AutoRTFM::IsSafeToReturnFromOpen<FMyStruct>);

            bool WasMoved = false;
            FMyStruct StructResult;
            AutoRTFM::ETransactionResult TransactionResult = AutoRTFM::Transact([&]
            {
                FMyStruct Closed = AutoRTFM::Open([&] { return FMyStruct{42, &WasMoved}; });
                AutoRTFM::Open([&] { StructResult = Closed; });
            });
            REQUIRE(AutoRTFM::ETransactionResult::Committed == TransactionResult);
            REQUIRE(true == WasMoved);
            REQUIRE(42 == StructResult.Value);
        }
    }
}