txdb.cpp

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Copyright (c) 2016-2020 The PIVX developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include "txdb.h"

#include "random.h"
#include "pow.h"
#include "uint256.h"
#include "util/system.h"
#include "util/vector.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_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';
// static const char DB_MONEY_SUPPLY = 'M';

namespace {

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

    SERIALIZE_METHODS(CoinEntry, obj) { READWRITE(obj.key, obj.outpoint->hash, VARINT(obj.outpoint->n)); }
};

}


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

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_ZERO;
    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;
}

bool CCoinsViewDB::BatchWrite(CCoinsMap& mapCoins,
                              const uint256& hashBlock,
                              const uint256& hashSaplingAnchor,
                              CAnchorsSaplingMap& mapSaplingAnchors,
                              CNullifiersMap& mapSaplingNullifiers)
{
    CDBBatch batch;
    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, Vector(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);
                }
            }
        }
    }

    // Write Sapling
    BatchWriteSapling(hashSaplingAnchor, mapSaplingAnchors, mapSaplingNullifiers, 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::WriteBlockIndex(const CDiskBlockIndex& blockindex)
{
    return Write(std::make_pair(DB_BLOCK_INDEX, blockindex.GetBlockHash()), blockindex);
}

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
    // 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;
    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);
}

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;
    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::WriteInt(const std::string& name, int nValue)
{
    return Write(std::make_pair('I', name), nValue);
}

bool CBlockTreeDB::ReadInt(const std::string& name, int& nValue)
{
    return Read(std::make_pair('I', name), nValue);
}

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

    pcursor->Seek(std::make_pair(DB_BLOCK_INDEX, UINT256_ZERO));

    // 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;

                // sapling
                pindexNew->nSaplingValue  = diskindex.nSaplingValue;
                pindexNew->hashFinalSaplingRoot = diskindex.hashFinalSaplingRoot;

                //zerocoin
                pindexNew->nAccumulatorCheckpoint = diskindex.nAccumulatorCheckpoint;

                //Proof Of Stake
                pindexNew->nFlags = diskindex.nFlags;
                pindexNew->vStakeModifier = diskindex.vStakeModifier;

                if (!Params().GetConsensus().NetworkUpgradeActive(pindexNew->nHeight, Consensus::UPGRADE_POS)) {
                    if (!CheckProofOfWork(pindexNew->GetBlockHash(), pindexNew->nBits))
                        return error("LoadBlockIndex() : CheckProofOfWork failed: %s", pindexNew->ToString());
                }

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

    return true;
}

CZerocoinDB::CZerocoinDB(size_t nCacheSize, bool fMemory, bool fWipe) : CDBWrapper(GetDataDir() / "zerocoin", nCacheSize, fMemory, fWipe)
{
}

bool CZerocoinDB::WriteCoinSpendBatch(const std::vector<std::pair<CBigNum, uint256> >& spendInfo)
{
    CDBBatch batch;
    size_t count = 0;
    for (std::vector<std::pair<CBigNum, uint256> >::const_iterator it=spendInfo.begin(); it != spendInfo.end(); it++) {
        CBigNum bnSerial = it->first;
        CDataStream ss(SER_GETHASH, 0);
        ss << bnSerial;
        uint256 hash = Hash(ss.begin(), ss.end());
        batch.Write(std::make_pair('s', hash), it->second);
        ++count;
    }

    LogPrint(BCLog::COINDB, "Writing %u coin spends to db.\n", (unsigned int)count);
    return WriteBatch(batch, true);
}

bool CZerocoinDB::ReadCoinSpend(const CBigNum& bnSerial, uint256& txHash)
{
    CDataStream ss(SER_GETHASH, 0);
    ss << bnSerial;
    uint256 hash = Hash(ss.begin(), ss.end());

    return Read(std::make_pair('s', hash), txHash);
}

bool CZerocoinDB::EraseCoinSpend(const CBigNum& bnSerial)
{
    CDataStream ss(SER_GETHASH, 0);
    ss << bnSerial;
    uint256 hash = Hash(ss.begin(), ss.end());

    return Erase(std::make_pair('s', hash));
}

// Legacy Zerocoin Database
static const char LZC_ACCUMCS = 'A';
//static const char LZC_MAPSUPPLY = 'M'; // TODO: add removal for LZC_MAPSUPPLY key-value if is found in db

bool CZerocoinDB::WriteAccChecksum(const uint32_t nChecksum, const libzerocoin::CoinDenomination denom, const int nHeight)
{
    return Write(std::make_pair(LZC_ACCUMCS, std::make_pair(nChecksum, denom)), nHeight);
}

bool CZerocoinDB::ReadAccChecksum(const uint32_t nChecksum, const libzerocoin::CoinDenomination denom, int& nHeightRet)
{
    return Read(std::make_pair(LZC_ACCUMCS, std::make_pair(nChecksum, denom)), nHeightRet);
}

bool CZerocoinDB::EraseAccChecksum(const uint32_t nChecksum, const libzerocoin::CoinDenomination denom)
{
    return Erase(std::make_pair(LZC_ACCUMCS, std::make_pair(nChecksum, denom)));
}

bool CZerocoinDB::WipeAccChecksums()
{
    std::unique_ptr<CDBIterator> pcursor(NewIterator());
    pcursor->Seek(std::make_pair(LZC_ACCUMCS, (uint32_t) 0));
    std::set<uint32_t> setDelete;
    while (pcursor->Valid()) {
        boost::this_thread::interruption_point();
        std::pair<char, uint32_t> key;
        if (pcursor->GetKey(key) && key.first == LZC_ACCUMCS) {
            uint32_t acs;
            if (pcursor->GetValue(acs)) {
                setDelete.insert(acs);
                pcursor->Next();
            } else {
                return error("%s : failed to read value", __func__);
            }
        } else {
            break;
        }
    }

    for (auto& acs : setDelete) {
        if (!Erase(std::make_pair(LZC_ACCUMCS, acs)))
            LogPrintf("%s: error failed to acc checksum %s\n", __func__, acs);
    }

    LogPrintf("%s: AccChecksum database removed.\n", __func__);
    return true;
}

namespace {

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

    //! 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;

    template <typename Stream>
    void Unserialize(Stream& s)
    {
        unsigned int nCode = 0;
        // version
        unsigned int nVersionDummy;
        ::Unserialize(s, VARINT(nVersionDummy));
        // header code
        ::Unserialize(s, VARINT(nCode));
        fCoinBase = nCode & 1;         //0001 - means coinbase
        fCoinStake = (nCode & 2) != 0; //0010 coinstake
        std::vector<bool> vAvail(2, false);
        vAvail[0] = (nCode & 4) != 0; // 0100
        vAvail[1] = (nCode & 8) != 0; // 1000
        unsigned int nMaskCode = (nCode / 16) + ((nCode & 12) != 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, Using<TxOutCompression>(vout[i]));
        }
        // coinbase height
        ::Unserialize(s, VARINT_MODE(nHeight, VarIntMode::NONNEGATIVE_SIGNED));
    }
};

}

/** Upgrade the database from older formats.
 *
 * Currently implemented:
 * - from the per-tx utxo model (4.2.0) to per-txout (4.2.99)
 */
bool CCoinsViewDB::Upgrade() {
    std::unique_ptr<CDBIterator> pcursor(db.NewIterator());
    pcursor->Seek(std::make_pair(DB_COINS, uint256()));
    if (!pcursor->Valid()) {
        return true;
    }

    LogPrintf("Upgrading database...\n");
    size_t batch_size = 1 << 24;
    CDBBatch batch;
    while (pcursor->Valid()) {
        boost::this_thread::interruption_point();
        std::pair<unsigned char, uint256> key;
        if (pcursor->GetKey(key) && key.first == DB_COINS) {
            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, old_coins.fCoinStake);
                    outpoint.n = i;
                    CoinEntry entry(&outpoint);
                    batch.Write(entry, newcoin);
                }
            }
            batch.Erase(key);
            if (batch.SizeEstimate() > batch_size) {
                db.WriteBatch(batch);
                batch.Clear();
            }
            pcursor->Next();
        } else {
            break;
        }
    }
    db.WriteBatch(batch);
    return true;
}