main.h

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Copyright (c) 2014-2015 The Dash developers
// Copyright (c) 2011-2013 The PPCoin developers
// Copyright (c) 2013-2014 The NovaCoin Developers
// Copyright (c) 2014-2018 The BlackCoin Developers
// Copyright (c) 2015-2020 The PIVX developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_MAIN_H
#define BITCOIN_MAIN_H

#if defined(HAVE_CONFIG_H)
#include "config/pivx-config.h"
#endif

#include "amount.h"
#include "chain.h"
#include "chainparams.h"
#include "coins.h"
#include "consensus/validation.h"
#include "net.h"
#include "pow.h"
#include "primitives/block.h"
#include "primitives/transaction.h"
#include "zpiv/zerocoin.h"
#include "zpiv/zpivmodule.h"
#include "script/script.h"
#include "script/sigcache.h"
#include "script/standard.h"
#include "sync.h"
#include "tinyformat.h"
#include "txmempool.h"
#include "uint256.h"
#include "undo.h"

#include <algorithm>
#include <atomic>
#include <exception>
#include <map>
#include <set>
#include <stdint.h>
#include <string>
#include <utility>
#include <vector>

#include "libzerocoin/CoinSpend.h"

#include <boost/unordered_map.hpp>

class CBlockIndex;
class CBlockTreeDB;
class CZerocoinDB;
class CSporkDB;
class CBloomFilter;
class CInv;
class CScriptCheck;
class CValidationInterface;
class CValidationState;

struct CBlockTemplate;
struct CNodeStateStats;

/** Default for -blockmaxsize and -blockminsize, which control the range of sizes the mining code will create **/
static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 750000;
static const unsigned int DEFAULT_BLOCK_MIN_SIZE = 0;
/** Default for -blockprioritysize, maximum space for zero/low-fee transactions **/
static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 50000;
/** The maximum size for transactions we're willing to relay/mine */
static const unsigned int MAX_STANDARD_TX_SIZE = 100000;
static const unsigned int MAX_ZEROCOIN_TX_SIZE = 150000;
/** Maximum number of signature check operations in an IsStandard() P2SH script */
static const unsigned int MAX_P2SH_SIGOPS = 15;
/** Default for -maxorphantx, maximum number of orphan transactions kept in memory */
static const unsigned int DEFAULT_MAX_ORPHAN_TRANSACTIONS = 100;
/** The maximum size of a blk?????.dat file (since 0.8) */
static const unsigned int MAX_BLOCKFILE_SIZE = 0x8000000; // 128 MiB
/** The pre-allocation chunk size for blk?????.dat files (since 0.8) */
static const unsigned int BLOCKFILE_CHUNK_SIZE = 0x1000000; // 16 MiB
/** The pre-allocation chunk size for rev?????.dat files (since 0.8) */
static const unsigned int UNDOFILE_CHUNK_SIZE = 0x100000; // 1 MiB
/** Maximum number of script-checking threads allowed */
static const int MAX_SCRIPTCHECK_THREADS = 16;
/** -par default (number of script-checking threads, 0 = auto) */
static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
/** Number of blocks that can be requested at any given time from a single peer. */
static const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
/** Timeout in seconds during which a peer must stall block download progress before being disconnected. */
static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
/** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
 *  less than this number, we reached their tip. Changing this value is a protocol upgrade. */
static const unsigned int MAX_HEADERS_RESULTS = 2000;
/** Size of the "block download window": how far ahead of our current height do we fetch?
 *  Larger windows tolerate larger download speed differences between peer, but increase the potential
 *  degree of disordering of blocks on disk (which make reindexing and in the future perhaps pruning
 *  harder). We'll probably want to make this a per-peer adaptive value at some point. */
static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
/** Time to wait (in seconds) between writing blocks/block index to disk. */
static const unsigned int DATABASE_WRITE_INTERVAL = 60 * 60;
/** Time to wait (in seconds) between flushing chainstate to disk. */
static const unsigned int DATABASE_FLUSH_INTERVAL = 24 * 60 * 60;
/** Maximum length of reject messages. */
static const unsigned int MAX_REJECT_MESSAGE_LENGTH = 111;

/** Enable bloom filter */
 static const bool DEFAULT_PEERBLOOMFILTERS = true;

/** If the tip is older than this (in seconds), the node is considered to be in initial block download. */
static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;

/** Default for -blockspamfilter, use header spam filter */
static const bool DEFAULT_BLOCK_SPAM_FILTER = true;
/** Default for -blockspamfiltermaxsize, maximum size of the list of indexes in the block spam filter */
static const unsigned int DEFAULT_BLOCK_SPAM_FILTER_MAX_SIZE = 100;
/** Default for -blockspamfiltermaxavg, maximum average size of an index occurrence in the block spam filter */
static const unsigned int DEFAULT_BLOCK_SPAM_FILTER_MAX_AVG = 10;

struct BlockHasher {
    size_t operator()(const uint256& hash) const { return hash.GetCheapHash(); }
};

extern CScript COINBASE_FLAGS;
extern RecursiveMutex cs_main;
extern CTxMemPool mempool;
typedef boost::unordered_map<uint256, CBlockIndex*, BlockHasher> BlockMap;
extern BlockMap mapBlockIndex;
extern uint64_t nLastBlockTx;
extern uint64_t nLastBlockSize;
extern const std::string strMessageMagic;
extern int64_t nTimeBestReceived;
extern int64_t nMoneySupply;

// Best block section
extern Mutex g_best_block_mutex;
extern std::condition_variable g_best_block_cv;
extern uint256 g_best_block;

extern std::atomic<bool> fImporting;
extern std::atomic<bool> fReindex;
extern int nScriptCheckThreads;
extern bool fTxIndex;
extern bool fIsBareMultisigStd;
extern bool fCheckBlockIndex;
extern size_t nCoinCacheUsage;
extern CFeeRate minRelayTxFee;
extern int64_t nMaxTipAge;
extern bool fVerifyingBlocks;

extern bool fLargeWorkForkFound;
extern bool fLargeWorkInvalidChainFound;

extern std::map<uint256, int64_t> mapRejectedBlocks;

/** Best header we've seen so far (used for getheaders queries' starting points). */
extern CBlockIndex* pindexBestHeader;

/** Minimum disk space required - used in CheckDiskSpace() */
static const uint64_t nMinDiskSpace = 52428800;

/** Register with a network node to receive its signals */
void RegisterNodeSignals(CNodeSignals& nodeSignals);
/** Unregister a network node */
void UnregisterNodeSignals(CNodeSignals& nodeSignals);

/**
 * Process an incoming block. This only returns after the best known valid
 * block is made active. Note that it does not, however, guarantee that the
 * specific block passed to it has been checked for validity!
 *
 * @param[out]  state   This may be set to an Error state if any error occurred processing it, including during validation/connection/etc of otherwise unrelated blocks during reorganisation; or it may be set to an Invalid state if pblock is itself invalid (but this is not guaranteed even when the block is checked). If you want to *possibly* get feedback on whether pblock is valid, you must also install a CValidationInterface - this will have its BlockChecked method called whenever *any* block completes validation.
 * @param[in]   pfrom   The node which we are receiving the block from; it is added to mapBlockSource and may be penalised if the block is invalid.
 * @param[in]   pblock  The block we want to process.
 * @param[out]  dbp     If pblock is stored to disk (or already there), this will be set to its location.
 * @return True if state.IsValid()
 */
bool ProcessNewBlock(CValidationState& state, CNode* pfrom, CBlock* pblock, CDiskBlockPos* dbp = NULL);
/** Check whether enough disk space is available for an incoming block */
bool CheckDiskSpace(uint64_t nAdditionalBytes = 0);
/** Open a block file (blk?????.dat) */
FILE* OpenBlockFile(const CDiskBlockPos& pos, bool fReadOnly = false);
/** Open an undo file (rev?????.dat) */
FILE* OpenUndoFile(const CDiskBlockPos& pos, bool fReadOnly = false);
/** Translation to a filesystem path */
boost::filesystem::path GetBlockPosFilename(const CDiskBlockPos& pos, const char* prefix);
/** Import blocks from an external file */
bool LoadExternalBlockFile(FILE* fileIn, CDiskBlockPos* dbp = NULL);
/** Initialize a new block tree database + block data on disk */
bool InitBlockIndex();
/** Load the block tree and coins database from disk */
bool LoadBlockIndex(std::string& strError);
/** Unload database information */
void UnloadBlockIndex();
/** See whether the protocol update is enforced for connected nodes */
int ActiveProtocol();
/** Process protocol messages received from a given node */
bool ProcessMessages(CNode* pfrom);
/**
 * Send queued protocol messages to be sent to a give node.
 *
 * @param[in]   pto             The node which we are sending messages to.
 * @param[in]   fSendTrickle    When true send the trickled data, otherwise trickle the data until true.
 */
bool SendMessages(CNode* pto, bool fSendTrickle);
/** Run an instance of the script checking thread */
void ThreadScriptCheck();

/** Check whether we are doing an initial block download (synchronizing from disk or network) */
bool IsInitialBlockDownload();
/** Format a string that describes several potential problems detected by the core */
std::string GetWarnings(std::string strFor);
/** Retrieve a transaction (from memory pool, or from disk, if possible) */
bool GetTransaction(const uint256& hash, CTransaction& tx, uint256& hashBlock, bool fAllowSlow = false, CBlockIndex* blockIndex = nullptr);
/** Retrieve an output (from memory pool, or from disk, if possible) */
bool GetOutput(const uint256& hash, unsigned int index, CValidationState& state, CTxOut& out);
/** Find the best known block, and make it the tip of the block chain */

// ***TODO***
double ConvertBitsToDouble(unsigned int nBits);
int64_t GetMasternodePayment();
unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader* pblock, bool fProofOfStake);

bool ActivateBestChain(CValidationState& state, CBlock* pblock = NULL, bool fAlreadyChecked = false);
CAmount GetBlockValue(int nHeight);

/** Create a new block index entry for a given block hash */
CBlockIndex* InsertBlockIndex(uint256 hash);
/** Get statistics from node state */
bool GetNodeStateStats(NodeId nodeid, CNodeStateStats& stats);
/** Increase a node's misbehavior score. */
void Misbehaving(NodeId nodeid, int howmuch);
/** Flush all state, indexes and buffers to disk. */
void FlushStateToDisk();


/** (try to) add transaction to memory pool **/
bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree, bool* pfMissingInputs, bool fRejectInsaneFee = false, bool ignoreFees = false);

bool AcceptableInputs(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree, bool* pfMissingInputs, bool fRejectInsaneFee = false, bool isDSTX = false);

int GetInputAge(CTxIn& vin);
int GetIXConfirmations(uint256 nTXHash);

struct CNodeStateStats {
    int nMisbehavior;
    int nSyncHeight;
    int nCommonHeight;
    std::vector<int> vHeightInFlight;
};

CAmount GetMinRelayFee(const CTransaction& tx, unsigned int nBytes, bool fAllowFree);

/**
 * Check transaction inputs, and make sure any
 * pay-to-script-hash transactions are evaluating IsStandard scripts
 *
 * Why bother? To avoid denial-of-service attacks; an attacker
 * can submit a standard HASH... OP_EQUAL transaction,
 * which will get accepted into blocks. The redemption
 * script can be anything; an attacker could use a very
 * expensive-to-check-upon-redemption script like:
 *   DUP CHECKSIG DROP ... repeated 100 times... OP_1
 */

/**
 * Check for standard transaction types
 * @param[in] mapInputs    Map of previous transactions that have outputs we're spending
 * @return True if all inputs (scriptSigs) use only standard transaction forms
 */
bool AreInputsStandard(const CTransaction& tx, const CCoinsViewCache& mapInputs);

/**
 * Check whether all inputs of this transaction are valid (no double spends, scripts & sigs, amounts)
 * This does not modify the UTXO set. If pvChecks is not NULL, script checks are pushed onto it
 * instead of being performed inline.
 */
bool CheckInputs(const CTransaction& tx, CValidationState& state, const CCoinsViewCache& view, bool fScriptChecks, unsigned int flags, bool cacheStore, std::vector<CScriptCheck>* pvChecks = NULL);

/** Apply the effects of this transaction on the UTXO set represented by view */
void UpdateCoins(const CTransaction& tx, CValidationState& state, CCoinsViewCache& inputs, CTxUndo& txundo, int nHeight);

bool IsTransactionInChain(const uint256& txId, int& nHeightTx, CTransaction& tx);
bool IsTransactionInChain(const uint256& txId, int& nHeightTx);
bool IsBlockHashInChain(const uint256& hashBlock);
bool ValidOutPoint(const COutPoint& out, int nHeight);

/**
 * Check if transaction will be final in the next block to be created.
 *
 * Calls IsFinalTx() with current block height and appropriate block time.
 *
 * See consensus/consensus.h for flag definitions.
 */
bool CheckFinalTx(const CTransaction& tx, int flags = -1);

/** Check for standard transaction types
 * @return True if all outputs (scriptPubKeys) use only standard transaction forms
 */
bool IsStandardTx(const CTransaction& tx, std::string& reason);

/**
 * Closure representing one script verification
 * Note that this stores references to the spending transaction
 */
class CScriptCheck
{
private:
    CScript scriptPubKey;
    const CTransaction* ptxTo;
    unsigned int nIn;
    unsigned int nFlags;
    bool cacheStore;
    ScriptError error;

public:
    CScriptCheck() : ptxTo(0), nIn(0), nFlags(0), cacheStore(false), error(SCRIPT_ERR_UNKNOWN_ERROR) {}
    CScriptCheck(const CCoins& txFromIn, const CTransaction& txToIn, unsigned int nInIn, unsigned int nFlagsIn, bool cacheIn) : scriptPubKey(txFromIn.vout[txToIn.vin[nInIn].prevout.n].scriptPubKey),
                                                                                                                                ptxTo(&txToIn), nIn(nInIn), nFlags(nFlagsIn), cacheStore(cacheIn), error(SCRIPT_ERR_UNKNOWN_ERROR) {}

    bool operator()();

    void swap(CScriptCheck& check)
    {
        scriptPubKey.swap(check.scriptPubKey);
        std::swap(ptxTo, check.ptxTo);
        std::swap(nIn, check.nIn);
        std::swap(nFlags, check.nFlags);
        std::swap(cacheStore, check.cacheStore);
        std::swap(error, check.error);
    }

    ScriptError GetScriptError() const { return error; }
};


/** Functions for disk access for blocks */
bool WriteBlockToDisk(CBlock& block, CDiskBlockPos& pos);
bool ReadBlockFromDisk(CBlock& block, const CDiskBlockPos& pos);
bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex);


/** Functions for validating blocks and updating the block tree */

/** Undo the effects of this block (with given index) on the UTXO set represented by coins.
 *  In case pfClean is provided, operation will try to be tolerant about errors, and *pfClean
 *  will be true if no problems were found. Otherwise, the return value will be false in case
 *  of problems. Note that in any case, coins may be modified. */
bool DisconnectBlock(CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& coins, bool* pfClean = NULL);

/** Reprocess a number of blocks to try and get on the correct chain again **/
bool DisconnectBlocks(int nBlocks);
void ReprocessBlocks(int nBlocks);

/** Apply the effects of this block (with given index) on the UTXO set represented by coins */
bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindex, CCoinsViewCache& coins, bool fJustCheck, bool fAlreadyChecked = false);

/** Context-independent validity checks */
bool CheckBlockHeader(const CBlockHeader& block, CValidationState& state, bool fCheckPOW = true);
bool CheckBlock(const CBlock& block, CValidationState& state, bool fCheckPOW = true, bool fCheckMerkleRoot = true, bool fCheckSig = true);
bool CheckWork(const CBlock block, CBlockIndex* const pindexPrev);

/** Context-dependent validity checks */
bool ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex* pindexPrev);
bool ContextualCheckBlock(const CBlock& block, CValidationState& state, CBlockIndex* pindexPrev);

/** Check a block is completely valid from start to finish (only works on top of our current best block, with cs_main held) */
bool TestBlockValidity(CValidationState& state, const CBlock& block, CBlockIndex* pindexPrev, bool fCheckPOW = true, bool fCheckMerkleRoot = true);

/** Store block on disk. If dbp is provided, the file is known to already reside on disk */
bool AcceptBlock(CBlock& block, CValidationState& state, CBlockIndex** pindex, CDiskBlockPos* dbp = NULL, bool fAlreadyCheckedBlock = false);
bool AcceptBlockHeader(const CBlockHeader& block, CValidationState& state, CBlockIndex** ppindex = NULL);


/** RAII wrapper for VerifyDB: Verify consistency of the block and coin databases */
class CVerifyDB
{
public:
    CVerifyDB();
    ~CVerifyDB();
    bool VerifyDB(CCoinsView* coinsview, int nCheckLevel, int nCheckDepth);
};

/** Find the last common block between the parameter chain and a locator. */
CBlockIndex* FindForkInGlobalIndex(const CChain& chain, const CBlockLocator& locator);

/** Mark a block as invalid. */
bool InvalidateBlock(CValidationState& state, CBlockIndex* pindex);

/** Remove invalidity status from a block and its descendants. */
bool ReconsiderBlock(CValidationState& state, CBlockIndex* pindex);

/** The currently-connected chain of blocks. */
extern CChain chainActive;

/** Global variable that points to the active CCoinsView (protected by cs_main) */
extern CCoinsViewCache* pcoinsTip;

/** Global variable that points to the active block tree (protected by cs_main) */
extern CBlockTreeDB* pblocktree;

/** Global variable that points to the zerocoin database (protected by cs_main) */
extern CZerocoinDB* zerocoinDB;

/** Global variable that points to the spork database (protected by cs_main) */
extern CSporkDB* pSporkDB;

#endif // BITCOIN_MAIN_H