ETLHelpers.hpp

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//------------------------------------------------------------------------------
/*
    This file is part of clio: https://github.com/XRPLF/clio
    Copyright (c) 2022, the clio developers.
 
    Permission to use, copy, modify, and distribute this software for any
    purpose with or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

#pragma once
 
#include <xrpl/basics/base_uint.h>
 
#include <condition_variable>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <mutex>
#include <optional>
#include <queue>
#include <vector>
 
namespace etl {
 
// TODO: does the note make sense? lockfree queues provide the same blocking behaviour just without
// mutex, don't they?
template <typename T>
class ThreadSafeQueue {
    std::queue<T> queue_;
 
    mutable std::mutex m_;
    std::condition_variable cv_;
    uint32_t maxSize_;
 
public:
    ThreadSafeQueue(uint32_t maxSize) : maxSize_(maxSize)
    {
    }

    void
    push(T const& elt)
    {
        std::unique_lock lck(m_);
        cv_.wait(lck, [this]() { return queue_.size() <= maxSize_; });
        queue_.push(elt);
        cv_.notify_all();
    }

    void
    push(T&& elt)
    {
        std::unique_lock lck(m_);
        cv_.wait(lck, [this]() { return queue_.size() <= maxSize_; });
        queue_.push(std::move(elt));
        cv_.notify_all();
    }

    T
    pop()
    {
        std::unique_lock lck(m_);
        cv_.wait(lck, [this]() { return !queue_.empty(); });
 
        T ret = std::move(queue_.front());
        queue_.pop();
 
        cv_.notify_all();
        return ret;
    }

    std::optional<T>
    tryPop()
    {
        std::scoped_lock const lck(m_);
        if (queue_.empty())
            return {};
 
        T ret = std::move(queue_.front());
        queue_.pop();
 
        cv_.notify_all();
        return ret;
    }

    std::size_t
    size() const
    {
        return queue_.size();
    }
};

std::vector<ripple::uint256>
getMarkers(size_t numMarkers);
 
}  // namespace etl