PeerGroup.h

#pragma once
 
#include <csf/Peer.h>
#include <csf/SimTime.h>
#include <csf/Validation.h>
#include <csf/random.h>
 
#include <algorithm>
#include <cassert>
#include <cstddef>
#include <iterator>
#include <ostream>
#include <random>
#include <set>
#include <utility>
#include <vector>
 
namespace xrpl::test::csf {

class PeerGroup
{
    using peers_type = std::vector<Peer*>;
    peers_type peers_;
 
public:
    using iterator = peers_type::iterator;
    using const_iterator = peers_type::const_iterator;
    using reference = peers_type::reference;
    using const_reference = peers_type::const_reference;
 
    PeerGroup() = default;
    PeerGroup(Peer* peer) : peers_{1, peer}
    {
    }
    PeerGroup(std::vector<Peer*>&& peers) : peers_{std::move(peers)}
    {
        std::ranges::sort(peers_);
    }
    PeerGroup(std::vector<Peer*> const& peers) : peers_{peers}
    {
        std::ranges::sort(peers_);
    }
 
    PeerGroup(std::set<Peer*> const& peers) : peers_{peers.begin(), peers.end()}
    {
    }
 
    iterator
    begin()
    {
        return peers_.begin();
    }
 
    iterator
    end()
    {
        return peers_.end();
    }
 
    [[nodiscard]] const_iterator
    begin() const
    {
        return peers_.begin();
    }
 
    [[nodiscard]] const_iterator
    end() const
    {
        return peers_.end();
    }
 
    const_reference
    operator[](std::size_t i) const
    {
        return peers_[i];
    }
 
    bool
    contains(Peer const* p)
    {
        return std::ranges::find(peers_, p) != peers_.end();
    }
 
    bool
    contains(PeerID id)
    {
        return std::ranges::find_if(peers_, [id](Peer const* p) { return p->id == id; }) !=
            peers_.end();
    }
 
    [[nodiscard]] std::size_t
    size() const
    {
        return peers_.size();
    }

    void
    trust(PeerGroup const& o)
    {
        for (Peer* p : peers_)
        {
            for (Peer* target : o.peers_)
            {
                p->trust(*target);
            }
        }
    }

    void
    untrust(PeerGroup const& o)
    {
        for (Peer* p : peers_)
        {
            for (Peer* target : o.peers_)
            {
                p->untrust(*target);
            }
        }
    }

    void
    connect(PeerGroup const& o, SimDuration delay)
    {
        for (Peer* p : peers_)
        {
            for (Peer* target : o.peers_)
            {
                // cannot send messages to self over network
                if (p != target)
                    p->connect(*target, delay);
            }
        }
    }

    void
    disconnect(PeerGroup const& o)
    {
        for (Peer* p : peers_)
        {
            for (Peer* target : o.peers_)
            {
                p->disconnect(*target);
            }
        }
    }

    void
    trustAndConnect(PeerGroup const& o, SimDuration delay)
    {
        trust(o);
        connect(o, delay);
    }

    void
    connectFromTrust(SimDuration delay)
    {
        for (Peer* peer : peers_)
        {
            for (Peer* to : peer->trustGraph.trustedPeers(peer))
            {
                peer->connect(*to, delay);
            }
        }
    }
 
    // Union of PeerGroups
    friend PeerGroup
    operator+(PeerGroup const& a, PeerGroup const& b)
    {
        PeerGroup res;
        std::ranges::set_union(a.peers_, b.peers_, std::back_inserter(res.peers_));
        return res;
    }
 
    // Set difference of PeerGroups
    friend PeerGroup
    operator-(PeerGroup const& a, PeerGroup const& b)
    {
        PeerGroup res;
 
        std::ranges::set_difference(a.peers_, b.peers_, std::back_inserter(res.peers_));
 
        return res;
    }
 
    friend std::ostream&
    operator<<(std::ostream& o, PeerGroup const& t)
    {
        o << "{";
        bool first = true;
        for (Peer const* p : t)
        {
            if (!first)
                o << ", ";
            first = false;
            o << p->id;
        }
        o << "}";
        return o;
    }
};

template <class RandomNumberDistribution, class Generator>
std::vector<PeerGroup>
randomRankedGroups(
    PeerGroup& peers,
    std::vector<double> const& ranks,
    int numGroups,
    RandomNumberDistribution sizeDist,
    Generator& g)
{
    assert(peers.size() == ranks.size());
 
    std::vector<PeerGroup> groups;
    groups.reserve(numGroups);
    std::vector<Peer*> rawPeers(peers.begin(), peers.end());
    std::generate_n(std::back_inserter(groups), numGroups, [&]() {
        std::vector<Peer*> res = randomWeightedShuffle(rawPeers, ranks, g);
        res.resize(sizeDist(g));
        return PeerGroup(std::move(res));
    });
 
    return groups;
}

template <class RandomNumberDistribution, class Generator>
void
randomRankedTrust(
    PeerGroup& peers,
    std::vector<double> const& ranks,
    int numGroups,
    RandomNumberDistribution sizeDist,
    Generator& g)
{
    std::vector<PeerGroup> const groups = randomRankedGroups(peers, ranks, numGroups, sizeDist, g);
    std::uniform_int_distribution<int> u(0, groups.size() - 1);  // NOLINT(misc-const-correctness)
 
    for (auto& peer : peers)
    {
        for (auto& target : groups[u(g)])
            peer->trust(*target);
    }
}

template <class RandomNumberDistribution, class Generator>
void
randomRankedConnect(
    PeerGroup& peers,
    std::vector<double> const& ranks,
    int numGroups,
    RandomNumberDistribution sizeDist,
    Generator& g,
    SimDuration delay)
{
    std::vector<PeerGroup> const groups = randomRankedGroups(peers, ranks, numGroups, sizeDist, g);
    std::uniform_int_distribution<int> u(0, groups.size() - 1);  // NOLINT(misc-const-correctness)
 
    for (auto& peer : peers)
    {
        for (auto& target : groups[u(g)])
            peer->connect(*target, delay);
    }
}
 
}  // namespace xrpl::test::csf