kevacoin/src/txdb.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <txdb.h>

#include <chainparams.h>
#include <hash.h>
#include <random.h>
#include <pow.h>
#include <uint256.h>
#include <util.h>
#include <ui_interface.h>
#include <init.h>
#include <script/keva.h>

#include <stdint.h>

#include <boost/thread.hpp>

static const char DB_COIN = 'C';
static const char DB_COINS = 'c';
static const char DB_BLOCK_FILES = 'f';
static const char DB_TXINDEX = 't';
static const char DB_BLOCK_INDEX = 'b';

static const char DB_NAME = 'n';

static const char DB_BEST_BLOCK = 'B';
static const char DB_HEAD_BLOCKS = 'H';
static const char DB_FLAG = 'F';
static const char DB_REINDEX_FLAG = 'R';
static const char DB_LAST_BLOCK = 'l';

namespace {

struct CoinEntry {
    COutPoint* outpoint;
    char key;
    explicit CoinEntry(const COutPoint* ptr) : outpoint(const_cast<COutPoint*>(ptr)), key(DB_COIN)  {}

    template<typename Stream>
    void Serialize(Stream &s) const {
        s << key;
        s << outpoint->hash;
        s << VARINT(outpoint->n);
    }

    template<typename Stream>
    void Unserialize(Stream& s) {
        s >> key;
        s >> outpoint->hash;
        s >> VARINT(outpoint->n);
    }
};

}

CCoinsViewDB::CCoinsViewDB(size_t nCacheSize, bool fMemory, bool fWipe) : db(GetDataDir() / "chainstate", nCacheSize, fMemory, fWipe, true)
{
}

bool CCoinsViewDB::GetCoin(const COutPoint &outpoint, Coin &coin) const {
    return db.Read(CoinEntry(&outpoint), coin);
}

bool CCoinsViewDB::HaveCoin(const COutPoint &outpoint) const {
    return db.Exists(CoinEntry(&outpoint));
}

uint256 CCoinsViewDB::GetBestBlock() const {
    uint256 hashBestChain;
    if (!db.Read(DB_BEST_BLOCK, hashBestChain))
        return uint256();
    return hashBestChain;
}

std::vector<uint256> CCoinsViewDB::GetHeadBlocks() const {
    std::vector<uint256> vhashHeadBlocks;
    if (!db.Read(DB_HEAD_BLOCKS, vhashHeadBlocks)) {
        return std::vector<uint256>();
    }
    return vhashHeadBlocks;
}

class CDbKeyIterator : public CKevaIterator
{

private:

    /* The backing LevelDB iterator.  */
    CDBIterator* iter;

public:

    ~CDbKeyIterator();

    /**
     * Construct a new name iterator for the database.
     * @param db The database to create the iterator for.
     */
    CDbKeyIterator(const CDBWrapper& db, const valtype& nameSpace);

    /* Implement iterator methods.  */
    void seek(const valtype& start);
    bool next(valtype& key, CKevaData& data);

};

CDbKeyIterator::~CDbKeyIterator() {
    delete iter;
}

CDbKeyIterator::CDbKeyIterator(const CDBWrapper& db, const valtype& ns)
    : iter(const_cast<CDBWrapper*>(&db)->NewIterator()), CKevaIterator(ns)
{
    seek(valtype());
}

void CDbKeyIterator::seek(const valtype& start) {
    iter->Seek(std::make_pair(DB_NAME, std::make_pair(nameSpace, start)));
}

bool CDbKeyIterator::next(valtype& key, CKevaData& data) {
    if (!iter->Valid())
        return false;

    std::pair<char, std::pair<valtype, valtype>> curKey;
    if (!iter->GetKey(curKey) || curKey.first != DB_NAME)
        return false;

    key = std::get<1>(curKey.second);

    if (!iter->GetValue(data)) {
        return error("%s : failed to read data from iterator", __func__);
    }

    iter->Next();
    return true;
}

CKevaIterator* CCoinsViewDB::IterateKeys(const valtype& nameSpace) const {
    return new CDbKeyIterator(db, nameSpace);
}

bool CCoinsViewDB::GetNamespace(const valtype &nameSpace, CKevaData &data) const {
    return db.Read(std::make_pair(DB_NAME, std::make_pair(nameSpace, CKevaScript::KEVA_DISPLAY_NAME_KEY)), data);
}

bool CCoinsViewDB::GetName(const valtype &nameSpace, const valtype &key, CKevaData &data) const {
    return db.Read(std::make_pair(DB_NAME, std::make_pair(nameSpace, key)), data);
}

bool CCoinsViewDB::GetNamesForHeight(unsigned nHeight, std::set<valtype>& names) const {
    names.clear();
#if 0
    /* It seems that there are no "const iterators" for LevelDB.  Since we
       only need read operations on it, use a const-cast to get around
       that restriction.  */
    boost::scoped_ptr<CDBIterator> pcursor(const_cast<CDBWrapper*>(&db)->NewIterator());

    const CKevaCache::ExpireEntry seekEntry(nHeight, valtype ());
    pcursor->Seek(std::make_pair(DB_NAME_EXPIRY, seekEntry));

    for (; pcursor->Valid(); pcursor->Next())
    {
        std::pair<char, CKevaCache::ExpireEntry> key;
        if (!pcursor->GetKey(key) || key.first != DB_NAME_EXPIRY)
            break;
        const CKevaCache::ExpireEntry& entry = key.second;

        assert (entry.nHeight >= nHeight);
        if (entry.nHeight > nHeight)
          break;

        const valtype& name = entry.name;
        if (names.count(name) > 0) {
            return error("%s : duplicate name '%s' in expire index",
                                    __func__, ValtypeToString(name).c_str());
        }
        names.insert(name);
    }
#endif
    return true;
}

bool CCoinsViewDB::BatchWrite(CCoinsMap &mapCoins, const uint256 &hashBlock, const CKevaCache &names) {
    CDBBatch batch(db);
    size_t count = 0;
    size_t changed = 0;
    size_t batch_size = (size_t)gArgs.GetArg("-dbbatchsize", nDefaultDbBatchSize);
    int crash_simulate = gArgs.GetArg("-dbcrashratio", 0);
    assert(!hashBlock.IsNull());

    uint256 old_tip = GetBestBlock();
    if (old_tip.IsNull()) {
        // We may be in the middle of replaying.
        std::vector<uint256> old_heads = GetHeadBlocks();
        if (old_heads.size() == 2) {
            assert(old_heads[0] == hashBlock);
            old_tip = old_heads[1];
        }
    }

    // In the first batch, mark the database as being in the middle of a
    // transition from old_tip to hashBlock.
    // A vector is used for future extensibility, as we may want to support
    // interrupting after partial writes from multiple independent reorgs.
    batch.Erase(DB_BEST_BLOCK);
    batch.Write(DB_HEAD_BLOCKS, std::vector<uint256>{hashBlock, old_tip});

    for (CCoinsMap::iterator it = mapCoins.begin(); it != mapCoins.end();) {
        if (it->second.flags & CCoinsCacheEntry::DIRTY) {
            CoinEntry entry(&it->first);
            if (it->second.coin.IsSpent())
                batch.Erase(entry);
            else
                batch.Write(entry, it->second.coin);
            changed++;
        }
        count++;
        CCoinsMap::iterator itOld = it++;
        mapCoins.erase(itOld);
        if (batch.SizeEstimate() > batch_size) {
            LogPrint(BCLog::COINDB, "Writing partial batch of %.2f MiB\n", batch.SizeEstimate() * (1.0 / 1048576.0));
            db.WriteBatch(batch);
            batch.Clear();
            if (crash_simulate) {
                static FastRandomContext rng;
                if (rng.randrange(crash_simulate) == 0) {
                    LogPrintf("Simulating a crash. Goodbye.\n");
                    _Exit(0);
                }
            }
        }
    }

    names.writeBatch(batch);

    // In the last batch, mark the database as consistent with hashBlock again.
    batch.Erase(DB_HEAD_BLOCKS);
    batch.Write(DB_BEST_BLOCK, hashBlock);

    LogPrint(BCLog::COINDB, "Writing final batch of %.2f MiB\n", batch.SizeEstimate() * (1.0 / 1048576.0));
    bool ret = db.WriteBatch(batch);
    LogPrint(BCLog::COINDB, "Committed %u changed transaction outputs (out of %u) to coin database...\n", (unsigned int)changed, (unsigned int)count);
    return ret;
}

size_t CCoinsViewDB::EstimateSize() const
{
    return db.EstimateSize(DB_COIN, (char)(DB_COIN+1));
}

CBlockTreeDB::CBlockTreeDB(size_t nCacheSize, bool fMemory, bool fWipe) : CDBWrapper(GetDataDir() / "blocks" / "index", nCacheSize, fMemory, fWipe) {
}

bool CBlockTreeDB::ReadBlockFileInfo(int nFile, CBlockFileInfo &info) {
    return Read(std::make_pair(DB_BLOCK_FILES, nFile), info);
}

bool CBlockTreeDB::WriteReindexing(bool fReindexing) {
    if (fReindexing)
        return Write(DB_REINDEX_FLAG, '1');
    else
        return Erase(DB_REINDEX_FLAG);
}

bool CBlockTreeDB::ReadReindexing(bool &fReindexing) {
    fReindexing = Exists(DB_REINDEX_FLAG);
    return true;
}

bool CBlockTreeDB::ReadLastBlockFile(int &nFile) {
    return Read(DB_LAST_BLOCK, nFile);
}

CCoinsViewCursor *CCoinsViewDB::Cursor() const
{
    CCoinsViewDBCursor *i = new CCoinsViewDBCursor(const_cast<CDBWrapper&>(db).NewIterator(), GetBestBlock());
    /* It seems that there are no "const iterators" for LevelDB.  Since we
       only need read operations on it, use a const-cast to get around
       that restriction.  */
    i->pcursor->Seek(DB_COIN);
    // Cache key of first record
    if (i->pcursor->Valid()) {
        CoinEntry entry(&i->keyTmp.second);
        i->pcursor->GetKey(entry);
        i->keyTmp.first = entry.key;
    } else {
        i->keyTmp.first = 0; // Make sure Valid() and GetKey() return false
    }
    return i;
}

bool CCoinsViewDBCursor::GetKey(COutPoint &key) const
{
    // Return cached key
    if (keyTmp.first == DB_COIN) {
        key = keyTmp.second;
        return true;
    }
    return false;
}

bool CCoinsViewDBCursor::GetValue(Coin &coin) const
{
    return pcursor->GetValue(coin);
}

unsigned int CCoinsViewDBCursor::GetValueSize() const
{
    return pcursor->GetValueSize();
}

bool CCoinsViewDBCursor::Valid() const
{
    return keyTmp.first == DB_COIN;
}

void CCoinsViewDBCursor::Next()
{
    pcursor->Next();
    CoinEntry entry(&keyTmp.second);
    if (!pcursor->Valid() || !pcursor->GetKey(entry)) {
        keyTmp.first = 0; // Invalidate cached key after last record so that Valid() and GetKey() return false
    } else {
        keyTmp.first = entry.key;
    }
}

bool CBlockTreeDB::WriteBatchSync(const std::vector<std::pair<int, const CBlockFileInfo*> >& fileInfo, int nLastFile, const std::vector<const CBlockIndex*>& blockinfo) {
    CDBBatch batch(*this);
    for (std::vector<std::pair<int, const CBlockFileInfo*> >::const_iterator it=fileInfo.begin(); it != fileInfo.end(); it++) {
        batch.Write(std::make_pair(DB_BLOCK_FILES, it->first), *it->second);
    }
    batch.Write(DB_LAST_BLOCK, nLastFile);
    for (std::vector<const CBlockIndex*>::const_iterator it=blockinfo.begin(); it != blockinfo.end(); it++) {
        batch.Write(std::make_pair(DB_BLOCK_INDEX, (*it)->GetBlockHash()), CDiskBlockIndex(*it));
    }
    return WriteBatch(batch, true);
}

void CKevaCache::writeBatch (CDBBatch& batch) const
{
  for (EntryMap::const_iterator i = entries.begin(); i != entries.end(); ++i) {
    std::pair<valtype, valtype> name = std::make_pair(std::get<0>(i->first), std::get<1>(i->first));
    batch.Write(std::make_pair(DB_NAME, name), i->second);
  }

  for (std::set<NamespaceKeyType>::const_iterator i = deleted.begin(); i != deleted.end(); ++i) {
    std::pair<valtype, valtype> name = std::make_pair(std::get<0>(*i), std::get<1>(*i));
    batch.Erase(std::make_pair(DB_NAME, name));
  }
}

bool CBlockTreeDB::ReadTxIndex(const uint256 &txid, CDiskTxPos &pos) {
    return Read(std::make_pair(DB_TXINDEX, txid), pos);
}

bool CBlockTreeDB::WriteTxIndex(const std::vector<std::pair<uint256, CDiskTxPos> >&vect) {
    CDBBatch batch(*this);
    for (std::vector<std::pair<uint256,CDiskTxPos> >::const_iterator it=vect.begin(); it!=vect.end(); it++)
        batch.Write(std::make_pair(DB_TXINDEX, it->first), it->second);
    return WriteBatch(batch);
}

bool CBlockTreeDB::WriteFlag(const std::string &name, bool fValue) {
    return Write(std::make_pair(DB_FLAG, name), fValue ? '1' : '0');
}

bool CBlockTreeDB::ReadFlag(const std::string &name, bool &fValue) {
    char ch;
    if (!Read(std::make_pair(DB_FLAG, name), ch))
        return false;
    fValue = ch == '1';
    return true;
}

bool CBlockTreeDB::LoadBlockIndexGuts(const Consensus::Params& consensusParams, std::function<CBlockIndex*(const uint256&)> insertBlockIndex)
{
    std::unique_ptr<CDBIterator> pcursor(NewIterator());

    pcursor->Seek(std::make_pair(DB_BLOCK_INDEX, uint256()));

    // Load mapBlockIndex
    while (pcursor->Valid()) {
        boost::this_thread::interruption_point();
        std::pair<char, uint256> key;
        if (pcursor->GetKey(key) && key.first == DB_BLOCK_INDEX) {
            CDiskBlockIndex diskindex;
            if (pcursor->GetValue(diskindex)) {
                // Construct block index object
                CBlockIndex* pindexNew = insertBlockIndex(diskindex.GetBlockHash());
                pindexNew->pprev          = insertBlockIndex(diskindex.hashPrev);
                pindexNew->nHeight        = diskindex.nHeight;
                pindexNew->nFile          = diskindex.nFile;
                pindexNew->nDataPos       = diskindex.nDataPos;
                pindexNew->nUndoPos       = diskindex.nUndoPos;
                pindexNew->nVersion       = diskindex.nVersion;
                pindexNew->hashMerkleRoot = diskindex.hashMerkleRoot;
                pindexNew->nTime          = diskindex.nTime;
                pindexNew->nBits          = diskindex.nBits;
                pindexNew->nNonce         = diskindex.nNonce;
                pindexNew->nStatus        = diskindex.nStatus;
                pindexNew->nTx            = diskindex.nTx;

                // Kevacoin: Disable PoW Sanity check while loading block index from disk.
                // We use the sha256 hash for the block index for performance reasons, which is recorded for later use.
                // CheckProofOfWork() uses the scrypt hash which is discarded after a block is accepted.
                // While it is technically feasible to verify the PoW, doing so takes several minutes as it
                // requires recomputing every PoW hash during every Kevacoin startup.
                // We opt instead to simply trust the data that is on your local disk.
                //if (!CheckProofOfWork(pindexNew->GetBlockHash(), pindexNew->nBits, consensusParams))
                //    return error("%s: CheckProofOfWork failed: %s", __func__, pindexNew->ToString());

                pcursor->Next();
            } else {
                return error("%s: failed to read value", __func__);
            }
        } else {
            break;
        }
    }

    return true;
}

namespace {

//! Legacy class to deserialize pre-pertxout database entries without reindex.
class CCoins
{
public:
    //! whether transaction is a coinbase
    bool fCoinBase;

    //! unspent transaction outputs; spent outputs are .IsNull(); spent outputs at the end of the array are dropped
    std::vector<CTxOut> vout;

    //! at which height this transaction was included in the active block chain
    int nHeight;

    //! empty constructor
    CCoins() : fCoinBase(false), vout(0), nHeight(0) { }

    template<typename Stream>
    void Unserialize(Stream &s) {
        unsigned int nCode = 0;
        // version
        int nVersionDummy;
        ::Unserialize(s, VARINT(nVersionDummy));
        // header code
        ::Unserialize(s, VARINT(nCode));
        fCoinBase = nCode & 1;
        std::vector<bool> vAvail(2, false);
        vAvail[0] = (nCode & 2) != 0;
        vAvail[1] = (nCode & 4) != 0;
        unsigned int nMaskCode = (nCode / 8) + ((nCode & 6) != 0 ? 0 : 1);
        // spentness bitmask
        while (nMaskCode > 0) {
            unsigned char chAvail = 0;
            ::Unserialize(s, chAvail);
            for (unsigned int p = 0; p < 8; p++) {
                bool f = (chAvail & (1 << p)) != 0;
                vAvail.push_back(f);
            }
            if (chAvail != 0)
                nMaskCode--;
        }
        // txouts themself
        vout.assign(vAvail.size(), CTxOut());
        for (unsigned int i = 0; i < vAvail.size(); i++) {
            if (vAvail[i])
                ::Unserialize(s, REF(CTxOutCompressor(vout[i])));
        }
        // coinbase height
        ::Unserialize(s, VARINT(nHeight));
    }
};

}

/** Upgrade the database from older formats.
 *
 * Currently implemented: from the per-tx utxo model (0.8..0.14.x) to per-txout.
 */
bool CCoinsViewDB::Upgrade() {
    std::unique_ptr<CDBIterator> pcursor(db.NewIterator());
    pcursor->Seek(std::make_pair(DB_COINS, uint256()));
    if (!pcursor->Valid()) {
        return true;
    }

    int64_t count = 0;
    LogPrintf("Upgrading utxo-set database...\n");
    LogPrintf("[0%%]...");
    uiInterface.ShowProgress(_("Upgrading UTXO database"), 0, true);
    size_t batch_size = 1 << 24;
    CDBBatch batch(db);
    int reportDone = 0;
    std::pair<unsigned char, uint256> key;
    std::pair<unsigned char, uint256> prev_key = {DB_COINS, uint256()};
    while (pcursor->Valid()) {
        boost::this_thread::interruption_point();
        if (ShutdownRequested()) {
            break;
        }
        if (pcursor->GetKey(key) && key.first == DB_COINS) {
            if (count++ % 256 == 0) {
                uint32_t high = 0x100 * *key.second.begin() + *(key.second.begin() + 1);
                int percentageDone = (int)(high * 100.0 / 65536.0 + 0.5);
                uiInterface.ShowProgress(_("Upgrading UTXO database"), percentageDone, true);
                if (reportDone < percentageDone/10) {
                    // report max. every 10% step
                    LogPrintf("[%d%%]...", percentageDone);
                    reportDone = percentageDone/10;
                }
            }
            CCoins old_coins;
            if (!pcursor->GetValue(old_coins)) {
                return error("%s: cannot parse CCoins record", __func__);
            }
            COutPoint outpoint(key.second, 0);
            for (size_t i = 0; i < old_coins.vout.size(); ++i) {
                if (!old_coins.vout[i].IsNull() && !old_coins.vout[i].scriptPubKey.IsUnspendable()) {
                    Coin newcoin(std::move(old_coins.vout[i]), old_coins.nHeight, old_coins.fCoinBase);
                    outpoint.n = i;
                    CoinEntry entry(&outpoint);
                    batch.Write(entry, newcoin);
                }
            }
            batch.Erase(key);
            if (batch.SizeEstimate() > batch_size) {
                db.WriteBatch(batch);
                batch.Clear();
                db.CompactRange(prev_key, key);
                prev_key = key;
            }
            pcursor->Next();
        } else {
            break;
        }
    }
    db.WriteBatch(batch);
    db.CompactRange({DB_COINS, uint256()}, key);
    uiInterface.ShowProgress("", 100, false);
    LogPrintf("[%s].\n", ShutdownRequested() ? "CANCELLED" : "DONE");
    return !ShutdownRequested();
}