rippled/modules/ripple_app/consensus/ripple_DisputedTx.cpp

//------------------------------------------------------------------------------
/*
    Copyright (c) 2011-2013, OpenCoin, Inc.
*/
//==============================================================================

#define TRUST_NETWORK

// Track a peer's yes/no vote on a particular disputed transaction
void DisputedTx::setVote (const uint160& peer, bool votesYes)
{
    // VFALCO TODO Simplify this declaration. It doesn't exactly roll off the tongue!
    std::pair <boost::unordered_map <const uint160, bool>::iterator, bool> res =
        mVotes.insert (std::pair<const uint160, bool> (peer, votesYes));

    // new vote
    if (res.second)
    {
        if (votesYes)
        {
            WriteLog (lsDEBUG, LedgerConsensus) << "Peer " << peer << " votes YES on " << mTransactionID;
            ++mYays;
        }
        else
        {
            WriteLog (lsDEBUG, LedgerConsensus) << "Peer " << peer << " votes NO on " << mTransactionID;
            ++mNays;
        }
    }
    // changes vote to yes
    else if (votesYes && !res.first->second)
    {
        WriteLog (lsDEBUG, LedgerConsensus) << "Peer " << peer << " now votes YES on " << mTransactionID;
        --mNays;
        ++mYays;
        res.first->second = true;
    }
    // changes vote to no
    else if (!votesYes && res.first->second)
    {
        WriteLog (lsDEBUG, LedgerConsensus) << "Peer " << peer << " now votes NO on " << mTransactionID;
        ++mNays;
        --mYays;
        res.first->second = false;
    }
}

// Remove a peer's vote on this disputed transasction
void DisputedTx::unVote (const uint160& peer)
{
    boost::unordered_map<uint160, bool>::iterator it = mVotes.find (peer);

    if (it != mVotes.end ())
    {
        if (it->second)
            --mYays;
        else
            --mNays;

        mVotes.erase (it);
    }
}

bool DisputedTx::updateVote (int percentTime, bool proposing)
{
    // VFALCO TODO Give the return value a descriptive local variable name
    //             and don't return from the middle.

    if (mOurVote && (mNays == 0))
        return false;

    if (!mOurVote && (mYays == 0))
        return false;

    bool newPosition;
    int weight;

    if (proposing) // give ourselves full weight
    {
        // This is basically the percentage of nodes voting 'yes' (including us)
        weight = (mYays * 100 + (mOurVote ? 100 : 0)) / (mNays + mYays + 1);

        // VFALCO TODO Rename these macros and turn them into language constructs.
        //             consolidate them into a class that collects all these related values.
        //
        // To prevent avalanche stalls, we increase the needed weight slightly over time
        if (percentTime < AV_MID_CONSENSUS_TIME)
            newPosition = weight >  AV_INIT_CONSENSUS_PCT;
        else if (percentTime < AV_LATE_CONSENSUS_TIME)
            newPosition = weight > AV_MID_CONSENSUS_PCT;
        else if (percentTime < AV_STUCK_CONSENSUS_TIME)
            newPosition = weight > AV_LATE_CONSENSUS_PCT;
        else
            newPosition = weight > AV_STUCK_CONSENSUS_PCT;
    }
    else // don't let us outweigh a proposing node, just recognize consensus
    {
        weight = -1;
        newPosition = mYays > mNays;
    }

    if (newPosition == mOurVote)
    {
        WriteLog (lsINFO, LedgerConsensus) <<
                                           "No change (" << (mOurVote ? "YES" : "NO") << ") : weight " << weight << ", percent " << percentTime;
        WriteLog (lsDEBUG, LedgerConsensus) << getJson ();
        return false;
    }

    mOurVote = newPosition;
    WriteLog (lsDEBUG, LedgerConsensus) << "We now vote " << (mOurVote ? "YES" : "NO") << " on " << mTransactionID;
    WriteLog (lsDEBUG, LedgerConsensus) << getJson ();
    return true;
}

Json::Value DisputedTx::getJson ()
{
    Json::Value ret (Json::objectValue);

    ret["yays"] = mYays;
    ret["nays"] = mNays;
    ret["our_vote"] = mOurVote;

    if (!mVotes.empty ())
    {
        Json::Value votesj (Json::objectValue);
        typedef boost::unordered_map<uint160, bool>::value_type vt;
        BOOST_FOREACH (vt & vote, mVotes)
        {
            votesj[vote.first.GetHex ()] = vote.second;
        }
        ret["votes"] = votesj;
    }

    return ret;
}