Class RandomCaller

tests/concurrent_queue_test/concurrent_queue_test.cpp:289–412

Calls random member functions of ConcurrentQueue for a limited time. Ensures that total equals 0 when all jobs are complete/canceled by: setting each job's summand to 1; subtracting a job set's size from total before enqueuing jobs in the set; adding canceled job count to total after cancelation.

//! * subtracting a job set's size from total before enqueuing jobs in the set;
//! * adding canceled job count to total after cancelation.
class RandomCaller
{
public:
    explicit RandomCaller(ConcurrentQueue &queue, Total &total, int threadId,
                          int queueThreadCount, RandomEngine &engine,
                          bool boostEnqueueOperationWeight)
        : queue(queue),
          total(total),
          threadId { threadId },
          boostEnqueueOperationWeight { boostEnqueueOperationWeight },
          printer(total, threadId, queueThreadCount),
          engine(engine)
    {
    }

    void operator()()
    {
        constexpr auto testDuration = chrono::milliseconds(10);
        const auto testStartTime = Clock::now();

        auto operation = operationDistribution();
        do {
            switch (operation(engine)) {
            case 0:
                enqueue();
                break;
            case 1:
                cancel();
                break;
            case 2:
                waitAndPrint(queue, printer);
                break;
            default:
                qFatal("Unsupported operation.");
            }
        } while (Clock::now() - testStartTime < testDuration);
    }

private:
    int randomInt(int a, int b)
    {
        return uniformInt(engine, decltype(uniformInt)::param_type(a, b));
    }

    using OperationDistribution = std::discrete_distribution<int>;

    void printProbabilities(const OperationDistribution &distribution) const
    {
        auto p = distribution.probabilities();
        constexpr std::size_t expectedProbabilityCount { 3 };
        if (p.size() != expectedProbabilityCount)
            qFatal("Wrong number of operation probabilities: %zu != %zu", p.size(), expectedProbabilityCount);

        for (auto &x : p)
            x *= 100; // Convert to percentages.
        log() << QStringLiteral("#%1 operation probabilities: e=%2%, c=%3%, w=%4%.").arg(threadId).arg(p[0]).arg(p[1]).arg(p[2]);
    }