LastSeenMessagesTracker.cpp

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#if PROTOCOL_VERSION > 759 /* > 1.19 */
 
#include "botcraft/Network/LastSeenMessagesTracker.hpp"
 
namespace Botcraft
{
    LastSeenMessagesTracker::LastSeenMessagesTracker()
    {
#if PROTOCOL_VERSION > 760 /* > 1.19.2 */
        tail = 0;
        offset = 0;
#endif
    }
 
    LastSeenMessagesTracker::~LastSeenMessagesTracker()
    {
 
    }
 
    std::mutex& LastSeenMessagesTracker::GetMutex()
    {
        return mutex;
    }
 
#if PROTOCOL_VERSION < 761 /* < 1.19.3 */
    const std::vector<unsigned char>& LastSeenMessagesTracker::GetLastSignature() const
    {
        return last_signature_sent;
    }
 
    void LastSeenMessagesTracker::SetLastSignature(const std::vector<unsigned char>& last_signature_sent_)
    {
        last_signature_sent = last_signature_sent_;
    }
 
    void LastSeenMessagesTracker::AddSeenMessage(const std::vector<unsigned char>& signature, const ProtocolCraft::UUID& sender)
    {
        std::scoped_lock<std::mutex> lock_messages(mutex);
 
        ProtocolCraft::LastSeenMessagesEntry entry;
        entry.SetLastSignature(signature);
        entry.SetProfileId(sender);
 
        // Remove old messages from the same player
        int index = 0;
        while (index < last_seen.size())
        {
            if (last_seen[index].GetProfileId() == sender)
            {
                last_seen.erase(last_seen.begin() + index);
            }
            else
            {
                index += 1;
            }
        }
 
        // Push new header in front
        last_seen.push_front(entry);
 
        // Limit the size to 5 messages
        while (last_seen.size() > 5)
        {
            last_seen.pop_back();
        }
    }
 
    ProtocolCraft::LastSeenMessagesUpdate LastSeenMessagesTracker::GetLastSeenMessagesUpdate() const
    {
        ProtocolCraft::LastSeenMessagesUpdate last_seen_messages_update;
        last_seen_messages_update.SetLastSeen({ last_seen.begin(), last_seen.begin() + std::min(static_cast<int>(last_seen.size()), 5) });
        return last_seen_messages_update;
    }
#else
    std::pair<std::vector<std::vector<unsigned char>>, ProtocolCraft::LastSeenMessagesUpdate> LastSeenMessagesTracker::GetLastSeenMessagesUpdate()
    {
        std::scoped_lock<std::mutex> lock_messages(mutex);
        std::pair<std::vector<std::vector<unsigned char>>, ProtocolCraft::LastSeenMessagesUpdate> output;
        output.second.SetOffset(GetAndResetOffset());
 
        output.first.reserve(last_seen_signatures.size());
        std::bitset<20> bitset;
        for (size_t i = 0; i < last_seen_signatures.size(); ++i)
        {
            const size_t index = (tail + i) % last_seen_signatures.size();
            if (last_seen_signatures[index].empty())
            {
                continue;
            }
            bitset.set(i, true);
            output.first.push_back(last_seen_signatures[index]);
        }
        output.second.SetAcknowledged(bitset);
 
#if PROTOCOL_VERSION > 769 /* > 1.21.4 */
        // Compute the checksum for last seen messages for 1.21.5+
        int checksum = 1;
 
        for (const auto& signature : output.first)
        {
            int signature_hashcode = 1;
            for (const unsigned char c : signature)
            {
                signature_hashcode = 31 * signature_hashcode + static_cast<int>(c);
            }
            checksum = 31 * checksum + signature_hashcode;
        }
 
        const unsigned char byte_checksum = static_cast<unsigned char>(checksum);
        output.second.SetChecksum(byte_checksum == 0 ? 1 : byte_checksum);
#endif
 
        return output;
    }
 
    void LastSeenMessagesTracker::AddSeenMessage(const std::vector<unsigned char>& signature)
    {
        last_seen_signatures[tail] = signature;
        tail = (tail + 1) % last_seen_signatures.size();
        offset += 1;
    }
 
    int LastSeenMessagesTracker::GetOffset() const
    {
        return offset;
    }
 
    int LastSeenMessagesTracker::GetAndResetOffset()
    {
        const int current_offset = offset;
        offset = 0;
        return current_offset;
    }
#endif
}
#endif