rippled/src/cpp/ripple/ripple_LedgerConsensus.h

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

#ifndef RIPPLE_LEDGERCONSENSUS_H
#define RIPPLE_LEDGERCONSENSUS_H

/** Manager for achieving consensus on the next ledger.

    This object is created when the consensus process starts, and
    is destroyed when the process is complete.
*/
class LedgerConsensus
    : public boost::enable_shared_from_this <LedgerConsensus>
    , public CountedObject <LedgerConsensus>
{
public:
    static char const* getCountedObjectName () { return "LedgerConsensus"; }

    LedgerConsensus (LedgerHash const & prevLCLHash, Ledger::ref previousLedger, uint32 closeTime);

    int startup ();

    Json::Value getJson (bool full);

    Ledger::ref peekPreviousLedger ()
    {
        return mPreviousLedger;
    }

    uint256 getLCL ()
    {
        return mPrevLedgerHash;
    }

    SHAMap::pointer getTransactionTree (uint256 const & hash, bool doAcquire);

    TransactionAcquire::pointer getAcquiring (uint256 const & hash);

    void mapComplete (uint256 const & hash, SHAMap::ref map, bool acquired);

    bool stillNeedTXSet (uint256 const & hash);

    void checkLCL ();

    void handleLCL (uint256 const & lclHash);

    void timerEntry ();

    // state handlers
    void statePreClose ();
    void stateEstablish ();
    void stateCutoff ();
    void stateFinished ();
    void stateAccepted ();

    bool haveConsensus (bool forReal);

    bool peerPosition (LedgerProposal::ref);

    bool peerHasSet (Peer::ref peer, uint256 const & set, protocol::TxSetStatus status);

    SHAMapAddNode peerGaveNodes (Peer::ref peer, uint256 const & setHash,
                                 const std::list<SHAMapNode>& nodeIDs, const std::list< Blob >& nodeData);

    bool isOurPubKey (const RippleAddress & k)
    {
        return k == mValPublic;
    }

    // test/debug
    void simulate ();

private:
    // final accept logic
    void accept (SHAMap::ref txSet, LoadEvent::pointer);

    void weHave (uint256 const & id, Peer::ref avoidPeer);
    void startAcquiring (TransactionAcquire::pointer);
    SHAMap::pointer find (uint256 const & hash);

    void createDisputes (SHAMap::ref, SHAMap::ref);
    void addDisputedTransaction (uint256 const& , Blob const & transaction);
    void adjustCount (SHAMap::ref map, const std::vector<uint160>& peers);
    void propose ();

    void addPosition (LedgerProposal&, bool ours);
    void removePosition (LedgerProposal&, bool ours);
    void sendHaveTxSet (uint256 const & set, bool direct);
    void applyTransactions (SHAMap::ref transactionSet, Ledger::ref targetLedger,
                            Ledger::ref checkLedger, CanonicalTXSet & failedTransactions, bool openLgr);
    int applyTransaction (TransactionEngine & engine, SerializedTransaction::ref txn, Ledger::ref targetLedger,
                          bool openLgr, bool retryAssured);

    uint32 roundCloseTime (uint32 closeTime);

    // manipulating our own position
    void statusChange (protocol::NodeEvent, Ledger & ledger);
    void takeInitialPosition (Ledger & initialLedger);
    void updateOurPositions ();
    void playbackProposals ();
    int getThreshold ();
    void closeLedger ();
    void checkOurValidation ();

    void beginAccept (bool synchronous);
    void endConsensus ();

private:
    // VFALCO TODO Rename these to look pretty
    enum LCState
    {
        lcsPRE_CLOSE,       // We haven't closed our ledger yet, but others might have
        lcsESTABLISH,       // Establishing consensus
        lcsFINISHED,        // We have closed on a transaction set
        lcsACCEPTED,        // We have accepted/validated a new last closed ledger
    };

    LCState mState;
    uint32 mCloseTime;                      // The wall time this ledger closed
    uint256 mPrevLedgerHash, mNewLedgerHash;
    Ledger::pointer mPreviousLedger;
    InboundLedger::pointer mAcquiringLedger;
    LedgerProposal::pointer mOurPosition;
    RippleAddress mValPublic, mValPrivate;
    bool mProposing, mValidating, mHaveCorrectLCL, mConsensusFail;

    int mCurrentMSeconds, mClosePercent, mCloseResolution;
    bool mHaveCloseTimeConsensus;

    boost::posix_time::ptime        mConsensusStartTime;
    int                             mPreviousProposers;
    int                             mPreviousMSeconds;

    // Convergence tracking, trusted peers indexed by hash of public key
    boost::unordered_map<uint160, LedgerProposal::pointer> mPeerPositions;

    // Transaction Sets, indexed by hash of transaction tree
    boost::unordered_map<uint256, SHAMap::pointer> mAcquired;
    boost::unordered_map<uint256, TransactionAcquire::pointer> mAcquiring;

    // Peer sets
    boost::unordered_map<uint256, std::vector< boost::weak_ptr<Peer> > > mPeerData;

    // Disputed transactions
    boost::unordered_map<uint256, DisputedTx::pointer> mDisputes;

    // Close time estimates
    std::map<uint32, int> mCloseTimes;

    // nodes that have bowed out of this consensus process
    boost::unordered_set<uint160> mDeadNodes;
};


#endif