ETLHelpers.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2020 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or 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.
*/
//==============================================================================
 
#ifndef RIPPLE_APP_REPORTING_ETLHELPERS_H_INCLUDED
#define RIPPLE_APP_REPORTING_ETLHELPERS_H_INCLUDED
#include <ripple/app/main/Application.h>
#include <ripple/ledger/ReadView.h>
#include <condition_variable>
#include <mutex>
#include <optional>
#include <queue>
#include <sstream>
 
namespace ripple {
 
class NetworkValidatedLedgers
{
    // max sequence validated by network
    std::optional<uint32_t> max_;
 
    mutable std::mutex m_;
 
    std::condition_variable cv_;
 
    bool stopping_ = false;
 
public:
    void
    push(uint32_t idx)
    {
        std::lock_guard lck(m_);
        if (!max_ || idx > *max_)
            max_ = idx;
        cv_.notify_all();
    }
 
    std::optional<uint32_t>
    getMostRecent()
    {
        std::unique_lock lck(m_);
        cv_.wait(lck, [this]() { return max_ || stopping_; });
        return max_;
    }
 
    bool
    waitUntilValidatedByNetwork(uint32_t sequence)
    {
        std::unique_lock lck(m_);
        cv_.wait(lck, [sequence, this]() {
            return (max_ && sequence <= *max_) || stopping_;
        });
        return !stopping_;
    }
 
    void
    stop()
    {
        std::lock_guard lck(m_);
        stopping_ = true;
        cv_.notify_all();
    }
};
 
template <class T>
class ThreadSafeQueue
{
    std::queue<T> queue_;
 
    mutable std::mutex m_;
    std::condition_variable cv_;
    std::optional<uint32_t> maxSize_;
 
public:
    explicit ThreadSafeQueue(uint32_t maxSize) : maxSize_(maxSize)
    {
    }
 
    ThreadSafeQueue() = default;
 
    void
    push(T const& elt)
    {
        std::unique_lock lck(m_);
        // if queue has a max size, wait until not full
        if (maxSize_)
            cv_.wait(lck, [this]() { return queue_.size() <= *maxSize_; });
        queue_.push(elt);
        cv_.notify_all();
    }
 
    void
    push(T&& elt)
    {
        std::unique_lock lck(m_);
        // if queue has a max size, wait until not full
        if (maxSize_)
            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();
        // if queue has a max size, unblock any possible pushers
        if (maxSize_)
            cv_.notify_all();
        return ret;
    }
};
 
inline std::vector<uint256>
getMarkers(size_t numMarkers)
{
    assert(numMarkers <= 256);
 
    unsigned char incr = 256 / numMarkers;
 
    std::vector<uint256> markers;
    markers.reserve(numMarkers);
    uint256 base{0};
    for (size_t i = 0; i < numMarkers; ++i)
    {
        markers.push_back(base);
        base.data()[0] += incr;
    }
    return markers;
}
 
}  // namespace ripple
#endif