lbrycrd/src/wallet/wallet.h

// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_WALLET_WALLET_H
#define BITCOIN_WALLET_WALLET_H

#include <amount.h>
#include <interfaces/chain.h>
#include <interfaces/handler.h>
#include <outputtype.h>
#include <policy/feerate.h>
#include <streams.h>
#include <tinyformat.h>
#include <ui_interface.h>
#include <util/strencodings.h>
#include <validationinterface.h>
#include <script/ismine.h>
#include <script/sign.h>
#include <util/system.h>
#include <wallet/crypter.h>
#include <wallet/coinselection.h>
#include <wallet/walletdb.h>
#include <wallet/walletutil.h>

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

//! Explicitly unload and delete the wallet.
//! Blocks the current thread after signaling the unload intent so that all
//! wallet clients release the wallet.
//! Note that, when blocking is not required, the wallet is implicitly unloaded
//! by the shared pointer deleter.
void UnloadWallet(std::shared_ptr<CWallet>&& wallet);

bool AddWallet(const std::shared_ptr<CWallet>& wallet);
bool RemoveWallet(const std::shared_ptr<CWallet>& wallet);
bool HasWallets();
std::vector<std::shared_ptr<CWallet>> GetWallets();
std::shared_ptr<CWallet> GetWallet(const std::string& name);
std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const WalletLocation& location, std::string& error, std::string& warning);

//! Default for -keypool
static const unsigned int DEFAULT_KEYPOOL_SIZE = 1000;
//! -paytxfee default
constexpr CAmount DEFAULT_PAY_TX_FEE = 0;
//! -fallbackfee default
static const CAmount DEFAULT_FALLBACK_FEE = 20000;
//! -discardfee default
static const CAmount DEFAULT_DISCARD_FEE = 10000;
//! -mintxfee default
static const CAmount DEFAULT_TRANSACTION_MINFEE = 1000;
//! minimum recommended increment for BIP 125 replacement txs
static const CAmount WALLET_INCREMENTAL_RELAY_FEE = 5000;
//! Default for -spendzeroconfchange
static const bool DEFAULT_SPEND_ZEROCONF_CHANGE = true;
//! Default for -walletrejectlongchains
static const bool DEFAULT_WALLET_REJECT_LONG_CHAINS = false;
//! Default for -avoidpartialspends
static const bool DEFAULT_AVOIDPARTIALSPENDS = false;
//! -txconfirmtarget default
static const unsigned int DEFAULT_TX_CONFIRM_TARGET = 6;
//! -walletrbf default
static const bool DEFAULT_WALLET_RBF = false;
static const bool DEFAULT_WALLETBROADCAST = true;
static const bool DEFAULT_DISABLE_WALLET = false;

//! Pre-calculated constants for input size estimation in *virtual size*
static constexpr size_t DUMMY_NESTED_P2WPKH_INPUT_SIZE = 91;

class CCoinControl;
class COutput;
class CReserveKey;
class CScript;
class CWalletTx;
struct FeeCalculation;
enum class FeeEstimateMode;

/** (client) version numbers for particular wallet features */
enum WalletFeature
{
    FEATURE_BASE = 10500, // the earliest version new wallets supports (only useful for getwalletinfo's clientversion output)

    FEATURE_WALLETCRYPT = 40000, // wallet encryption
    FEATURE_COMPRPUBKEY = 60000, // compressed public keys

    FEATURE_HD = 130000, // Hierarchical key derivation after BIP32 (HD Wallet)

    FEATURE_HD_SPLIT = 139900, // Wallet with HD chain split (change outputs will use m/0'/1'/k)

    FEATURE_NO_DEFAULT_KEY = 159900, // Wallet without a default key written

    FEATURE_PRE_SPLIT_KEYPOOL = 169900, // Upgraded to HD SPLIT and can have a pre-split keypool

    FEATURE_LATEST = FEATURE_PRE_SPLIT_KEYPOOL
};

//! Default for -addresstype
constexpr OutputType DEFAULT_ADDRESS_TYPE{OutputType::P2SH_SEGWIT};

//! Default for -changetype
constexpr OutputType DEFAULT_CHANGE_TYPE{OutputType::CHANGE_AUTO};

enum WalletFlags : uint64_t {
    // wallet flags in the upper section (> 1 << 31) will lead to not opening the wallet if flag is unknown
    // unknown wallet flags in the lower section <= (1 << 31) will be tolerated

    // Indicates that the metadata has already been upgraded to contain key origins
    WALLET_FLAG_KEY_ORIGIN_METADATA = (1ULL << 1),

    // will enforce the rule that the wallet can't contain any private keys (only watch-only/pubkeys)
    WALLET_FLAG_DISABLE_PRIVATE_KEYS = (1ULL << 32),

    //! Flag set when a wallet contains no HD seed and no private keys, scripts,
    //! addresses, and other watch only things, and is therefore "blank."
    //!
    //! The only function this flag serves is to distinguish a blank wallet from
    //! a newly created wallet when the wallet database is loaded, to avoid
    //! initialization that should only happen on first run.
    //!
    //! This flag is also a mandatory flag to prevent previous versions of
    //! bitcoin from opening the wallet, thinking it was newly created, and
    //! then improperly reinitializing it.
    WALLET_FLAG_BLANK_WALLET = (1ULL << 33),
};

static constexpr uint64_t g_known_wallet_flags = WALLET_FLAG_DISABLE_PRIVATE_KEYS | WALLET_FLAG_BLANK_WALLET | WALLET_FLAG_KEY_ORIGIN_METADATA;

/** A key pool entry */
class CKeyPool
{
public:
    int64_t nTime;
    CPubKey vchPubKey;
    bool fInternal; // for change outputs
    bool m_pre_split; // For keys generated before keypool split upgrade

    CKeyPool();
    CKeyPool(const CPubKey& vchPubKeyIn, bool internalIn);

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        int nVersion = s.GetVersion();
        if (!(s.GetType() & SER_GETHASH))
            READWRITE(nVersion);
        READWRITE(nTime);
        READWRITE(vchPubKey);
        if (ser_action.ForRead()) {
            try {
                READWRITE(fInternal);
            }
            catch (std::ios_base::failure&) {
                /* flag as external address if we can't read the internal boolean
                   (this will be the case for any wallet before the HD chain split version) */
                fInternal = false;
            }
            try {
                READWRITE(m_pre_split);
            }
            catch (std::ios_base::failure&) {
                /* flag as postsplit address if we can't read the m_pre_split boolean
                   (this will be the case for any wallet that upgrades to HD chain split)*/
                m_pre_split = false;
            }
        }
        else {
            READWRITE(fInternal);
            READWRITE(m_pre_split);
        }
    }
};

/** Address book data */
class CAddressBookData
{
public:
    std::string name;
    std::string purpose;

    CAddressBookData() : purpose("unknown") {}

    typedef std::map<std::string, std::string> StringMap;
    StringMap destdata;
};

struct CRecipient
{
    CScript scriptPubKey;
    CAmount nAmount;
    bool fSubtractFeeFromAmount;
};

typedef std::map<std::string, std::string> mapValue_t;


static inline void ReadOrderPos(int64_t& nOrderPos, mapValue_t& mapValue)
{
    if (!mapValue.count("n"))
    {
        nOrderPos = -1; // TODO: calculate elsewhere
        return;
    }
    nOrderPos = atoi64(mapValue["n"].c_str());
}


static inline void WriteOrderPos(const int64_t& nOrderPos, mapValue_t& mapValue)
{
    if (nOrderPos == -1)
        return;
    mapValue["n"] = i64tostr(nOrderPos);
}

struct COutputEntry
{
    CTxDestination destination;
    CAmount amount;
    int vout;
};

/** A transaction with a merkle branch linking it to the block chain. */
class CMerkleTx
{
private:
  /** Constant used in hashBlock to indicate tx has been abandoned */
    static const uint256 ABANDON_HASH;

public:
    CTransactionRef tx;
    uint256 hashBlock;

    /* An nIndex == -1 means that hashBlock (in nonzero) refers to the earliest
     * block in the chain we know this or any in-wallet dependency conflicts
     * with. Older clients interpret nIndex == -1 as unconfirmed for backward
     * compatibility.
     */
    int nIndex;

    CMerkleTx()
    {
        SetTx(MakeTransactionRef());
        Init();
    }

    explicit CMerkleTx(CTransactionRef arg)
    {
        SetTx(std::move(arg));
        Init();
    }

    void Init()
    {
        hashBlock = uint256();
        nIndex = -1;
    }

    void SetTx(CTransactionRef arg)
    {
        tx = std::move(arg);
    }

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        std::vector<uint256> vMerkleBranch; // For compatibility with older versions.
        READWRITE(tx);
        READWRITE(hashBlock);
        READWRITE(vMerkleBranch);
        READWRITE(nIndex);
    }

    void SetMerkleBranch(const uint256& block_hash, int posInBlock);

    /**
     * Return depth of transaction in blockchain:
     * <0  : conflicts with a transaction this deep in the blockchain
     *  0  : in memory pool, waiting to be included in a block
     * >=1 : this many blocks deep in the main chain
     */
    int GetDepthInMainChain(interfaces::Chain::Lock& locked_chain) const;
    bool IsInMainChain(interfaces::Chain::Lock& locked_chain) const { return GetDepthInMainChain(locked_chain) > 0; }

    /**
     * @return number of blocks to maturity for this transaction:
     *  0 : is not a coinbase transaction, or is a mature coinbase transaction
     * >0 : is a coinbase transaction which matures in this many blocks
     */
    int GetBlocksToMaturity(interfaces::Chain::Lock& locked_chain) const;
    bool hashUnset() const { return (hashBlock.IsNull() || hashBlock == ABANDON_HASH); }
    bool isAbandoned() const { return (hashBlock == ABANDON_HASH); }
    void setAbandoned() { hashBlock = ABANDON_HASH; }

    const uint256& GetHash() const { return tx->GetHash(); }
    bool IsCoinBase() const { return tx->IsCoinBase(); }
    bool IsImmatureCoinBase(interfaces::Chain::Lock& locked_chain) const;
};

//Get the marginal bytes of spending the specified output
int CalculateMaximumSignedInputSize(const CTxOut& txout, const CWallet* pwallet, bool use_max_sig = false);

/**
 * A transaction with a bunch of additional info that only the owner cares about.
 * It includes any unrecorded transactions needed to link it back to the block chain.
 */
class CWalletTx : public CMerkleTx
{
private:
    const CWallet* pwallet;

public:
    /**
     * Key/value map with information about the transaction.
     *
     * The following keys can be read and written through the map and are
     * serialized in the wallet database:
     *
     *     "comment", "to"   - comment strings provided to sendtoaddress,
     *                         and sendmany wallet RPCs
     *     "replaces_txid"   - txid (as HexStr) of transaction replaced by
     *                         bumpfee on transaction created by bumpfee
     *     "replaced_by_txid" - txid (as HexStr) of transaction created by
     *                         bumpfee on transaction replaced by bumpfee
     *     "from", "message" - obsolete fields that could be set in UI prior to
     *                         2011 (removed in commit 4d9b223)
     *
     * The following keys are serialized in the wallet database, but shouldn't
     * be read or written through the map (they will be temporarily added and
     * removed from the map during serialization):
     *
     *     "fromaccount"     - serialized strFromAccount value
     *     "n"               - serialized nOrderPos value
     *     "timesmart"       - serialized nTimeSmart value
     *     "spent"           - serialized vfSpent value that existed prior to
     *                         2014 (removed in commit 93a18a3)
     */
    mapValue_t mapValue;
    std::vector<std::pair<std::string, std::string> > vOrderForm;
    unsigned int fTimeReceivedIsTxTime;
    unsigned int nTimeReceived; //!< time received by this node
    /**
     * Stable timestamp that never changes, and reflects the order a transaction
     * was added to the wallet. Timestamp is based on the block time for a
     * transaction added as part of a block, or else the time when the
     * transaction was received if it wasn't part of a block, with the timestamp
     * adjusted in both cases so timestamp order matches the order transactions
     * were added to the wallet. More details can be found in
     * CWallet::ComputeTimeSmart().
     */
    unsigned int nTimeSmart;
    /**
     * From me flag is set to 1 for transactions that were created by the wallet
     * on this bitcoin node, and set to 0 for transactions that were created
     * externally and came in through the network or sendrawtransaction RPC.
     */
    char fFromMe;
    int64_t nOrderPos; //!< position in ordered transaction list
    std::multimap<int64_t, CWalletTx*>::const_iterator m_it_wtxOrdered;

    // memory only
    mutable bool fDebitCached;
    mutable bool fCreditCached;
    mutable bool fImmatureCreditCached;
    mutable bool fAvailableCreditCached;
    mutable bool fWatchDebitCached;
    mutable bool fWatchCreditCached;
    mutable bool fImmatureWatchCreditCached;
    mutable bool fAvailableWatchCreditCached;
    mutable bool fChangeCached;
    mutable bool fInMempool;
    mutable CAmount nDebitCached;
    mutable CAmount nCreditCached;
    mutable CAmount nImmatureCreditCached;
    mutable CAmount nAvailableCreditCached;
    mutable CAmount nWatchDebitCached;
    mutable CAmount nWatchCreditCached;
    mutable CAmount nImmatureWatchCreditCached;
    mutable CAmount nAvailableWatchCreditCached;
    mutable CAmount nChangeCached;

    CWalletTx(const CWallet* pwalletIn, CTransactionRef arg) : CMerkleTx(std::move(arg))
    {
        Init(pwalletIn);
    }

    void Init(const CWallet* pwalletIn)
    {
        pwallet = pwalletIn;
        mapValue.clear();
        vOrderForm.clear();
        fTimeReceivedIsTxTime = false;
        nTimeReceived = 0;
        nTimeSmart = 0;
        fFromMe = false;
        fDebitCached = false;
        fCreditCached = false;
        fImmatureCreditCached = false;
        fAvailableCreditCached = false;
        fWatchDebitCached = false;
        fWatchCreditCached = false;
        fImmatureWatchCreditCached = false;
        fAvailableWatchCreditCached = false;
        fChangeCached = false;
        fInMempool = false;
        nDebitCached = 0;
        nCreditCached = 0;
        nImmatureCreditCached = 0;
        nAvailableCreditCached = 0;
        nWatchDebitCached = 0;
        nWatchCreditCached = 0;
        nAvailableWatchCreditCached = 0;
        nImmatureWatchCreditCached = 0;
        nChangeCached = 0;
        nOrderPos = -1;
    }

    template<typename Stream>
    void Serialize(Stream& s) const
    {
        char fSpent = false;
        mapValue_t mapValueCopy = mapValue;

        mapValueCopy["fromaccount"] = "";
        WriteOrderPos(nOrderPos, mapValueCopy);
        if (nTimeSmart) {
            mapValueCopy["timesmart"] = strprintf("%u", nTimeSmart);
        }

        s << static_cast<const CMerkleTx&>(*this);
        std::vector<CMerkleTx> vUnused; //!< Used to be vtxPrev
        s << vUnused << mapValueCopy << vOrderForm << fTimeReceivedIsTxTime << nTimeReceived << fFromMe << fSpent;
    }

    template<typename Stream>
    void Unserialize(Stream& s)
    {
        Init(nullptr);
        char fSpent;

        s >> static_cast<CMerkleTx&>(*this);
        std::vector<CMerkleTx> vUnused; //!< Used to be vtxPrev
        s >> vUnused >> mapValue >> vOrderForm >> fTimeReceivedIsTxTime >> nTimeReceived >> fFromMe >> fSpent;

        ReadOrderPos(nOrderPos, mapValue);
        nTimeSmart = mapValue.count("timesmart") ? (unsigned int)atoi64(mapValue["timesmart"]) : 0;

        mapValue.erase("fromaccount");
        mapValue.erase("spent");
        mapValue.erase("n");
        mapValue.erase("timesmart");
    }

    //! make sure balances are recalculated
    void MarkDirty()
    {
        fCreditCached = false;
        fAvailableCreditCached = false;
        fImmatureCreditCached = false;
        fWatchDebitCached = false;
        fWatchCreditCached = false;
        fAvailableWatchCreditCached = false;
        fImmatureWatchCreditCached = false;
        fDebitCached = false;
        fChangeCached = false;
    }

    void BindWallet(CWallet *pwalletIn)
    {
        pwallet = pwalletIn;
        MarkDirty();
    }

    //! filter decides which addresses will count towards the debit
    CAmount GetDebit(const isminefilter& filter) const;
    CAmount GetCredit(interfaces::Chain::Lock& locked_chain, const isminefilter& filter) const;
    CAmount GetImmatureCredit(interfaces::Chain::Lock& locked_chain, bool fUseCache=true) const;
    // TODO: Remove "NO_THREAD_SAFETY_ANALYSIS" and replace it with the correct
    // annotation "EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)". The
    // annotation "NO_THREAD_SAFETY_ANALYSIS" was temporarily added to avoid
    // having to resolve the issue of member access into incomplete type CWallet.
    CAmount GetAvailableCredit(interfaces::Chain::Lock& locked_chain, bool fUseCache=true, const isminefilter& filter=ISMINE_SPENDABLE) const NO_THREAD_SAFETY_ANALYSIS;
    CAmount GetImmatureWatchOnlyCredit(interfaces::Chain::Lock& locked_chain, const bool fUseCache=true) const;
    CAmount GetChange() const;

    // Get the marginal bytes if spending the specified output from this transaction
    int GetSpendSize(unsigned int out, bool use_max_sig = false) const
    {
        return CalculateMaximumSignedInputSize(tx->vout[out], pwallet, use_max_sig);
    }

    void GetAmounts(std::list<COutputEntry>& listReceived,
                    std::list<COutputEntry>& listSent, CAmount& nFee, const isminefilter& filter) const;

    bool IsFromMe(const isminefilter& filter) const
    {
        return (GetDebit(filter) > 0);
    }

    // True if only scriptSigs are different
    bool IsEquivalentTo(const CWalletTx& tx) const;

    bool InMempool() const;
    bool IsTrusted(interfaces::Chain::Lock& locked_chain) const;

    int64_t GetTxTime() const;

    // Pass this transaction to the node to relay to its peers
    bool RelayWalletTransaction(interfaces::Chain::Lock& locked_chain);

    /** Pass this transaction to the mempool. Fails if absolute fee exceeds absurd fee. */
    bool AcceptToMemoryPool(interfaces::Chain::Lock& locked_chain, CValidationState& state);

    // TODO: Remove "NO_THREAD_SAFETY_ANALYSIS" and replace it with the correct
    // annotation "EXCLUSIVE_LOCKS_REQUIRED(pwallet->cs_wallet)". The annotation
    // "NO_THREAD_SAFETY_ANALYSIS" was temporarily added to avoid having to
    // resolve the issue of member access into incomplete type CWallet. Note
    // that we still have the runtime check "AssertLockHeld(pwallet->cs_wallet)"
    // in place.
    std::set<uint256> GetConflicts() const NO_THREAD_SAFETY_ANALYSIS;
};

class COutput
{
public:
    const CWalletTx *tx;
    int i;
    int nDepth;

    /** Pre-computed estimated size of this output as a fully-signed input in a transaction. Can be -1 if it could not be calculated */
    int nInputBytes;

    /** Whether we have the private keys to spend this output */
    bool fSpendable;

    /** Whether we know how to spend this output, ignoring the lack of keys */
    bool fSolvable;

    /** Whether to use the maximum sized, 72 byte signature when calculating the size of the input spend. This should only be set when watch-only outputs are allowed */
    bool use_max_sig;

    /**
     * Whether this output is considered safe to spend. Unconfirmed transactions
     * from outside keys and unconfirmed replacement transactions are considered
     * unsafe and will not be used to fund new spending transactions.
     */
    bool fSafe;

    COutput(const CWalletTx *txIn, int iIn, int nDepthIn, bool fSpendableIn, bool fSolvableIn, bool fSafeIn, bool use_max_sig_in = false)
    {
        tx = txIn; i = iIn; nDepth = nDepthIn; fSpendable = fSpendableIn; fSolvable = fSolvableIn; fSafe = fSafeIn; nInputBytes = -1; use_max_sig = use_max_sig_in;
        // If known and signable by the given wallet, compute nInputBytes
        // Failure will keep this value -1
        if (fSpendable && tx) {
            nInputBytes = tx->GetSpendSize(i, use_max_sig);
        }
    }

    std::string ToString() const;

    inline CInputCoin GetInputCoin() const
    {
        return CInputCoin(tx->tx, i, nInputBytes);
    }
};

/** Private key that includes an expiration date in case it never gets used. */
class CWalletKey
{
public:
    CPrivKey vchPrivKey;
    int64_t nTimeCreated;
    int64_t nTimeExpires;
    std::string strComment;
    // todo: add something to note what created it (user, getnewaddress, change)
    //   maybe should have a map<string, string> property map

    explicit CWalletKey(int64_t nExpires=0);

    ADD_SERIALIZE_METHODS;

    template <typename Stream, typename Operation>
    inline void SerializationOp(Stream& s, Operation ser_action) {
        int nVersion = s.GetVersion();
        if (!(s.GetType() & SER_GETHASH))
            READWRITE(nVersion);
        READWRITE(vchPrivKey);
        READWRITE(nTimeCreated);
        READWRITE(nTimeExpires);
        READWRITE(LIMITED_STRING(strComment, 65536));
    }
};

struct CoinSelectionParams
{
    bool use_bnb = true;
    size_t change_output_size = 0;
    size_t change_spend_size = 0;
    CFeeRate effective_fee = CFeeRate(0);
    size_t tx_noinputs_size = 0;

    CoinSelectionParams(bool use_bnb, size_t change_output_size, size_t change_spend_size, CFeeRate effective_fee, size_t tx_noinputs_size) : use_bnb(use_bnb), change_output_size(change_output_size), change_spend_size(change_spend_size), effective_fee(effective_fee), tx_noinputs_size(tx_noinputs_size) {}
    CoinSelectionParams() {}
};

class WalletRescanReserver; //forward declarations for ScanForWalletTransactions/RescanFromTime
/**
 * A CWallet is an extension of a keystore, which also maintains a set of transactions and balances,
 * and provides the ability to create new transactions.
 */
class CWallet final : public CCryptoKeyStore, private interfaces::Chain::Notifications
{
private:
    std::atomic<bool> fAbortRescan{false};
    std::atomic<bool> fScanningWallet{false}; // controlled by WalletRescanReserver
    std::mutex mutexScanning;
    friend class WalletRescanReserver;

    WalletBatch *encrypted_batch GUARDED_BY(cs_wallet) = nullptr;

    //! the current wallet version: clients below this version are not able to load the wallet
    int nWalletVersion GUARDED_BY(cs_wallet){FEATURE_BASE};

    //! the maximum wallet format version: memory-only variable that specifies to what version this wallet may be upgraded
    int nWalletMaxVersion GUARDED_BY(cs_wallet) = FEATURE_BASE;

    int64_t nNextResend = 0;
    int64_t nLastResend = 0;
    bool fBroadcastTransactions = false;
    // Local time that the tip block was received. Used to schedule wallet rebroadcasts.
    std::atomic<int64_t> m_best_block_time {0};

    /**
     * Used to keep track of spent outpoints, and
     * detect and report conflicts (double-spends or
     * mutated transactions where the mutant gets mined).
     */
    typedef std::multimap<COutPoint, uint256> TxSpends;
    TxSpends mapTxSpends GUARDED_BY(cs_wallet);
    void AddToSpends(const COutPoint& outpoint, const uint256& wtxid) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void AddToSpends(const uint256& wtxid) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /**
     * Add a transaction to the wallet, or update it.  pIndex and posInBlock should
     * be set when the transaction was known to be included in a block.  When
     * pIndex == nullptr, then wallet state is not updated in AddToWallet, but
     * notifications happen and cached balances are marked dirty.
     *
     * If fUpdate is true, existing transactions will be updated.
     * TODO: One exception to this is that the abandoned state is cleared under the
     * assumption that any further notification of a transaction that was considered
     * abandoned is an indication that it is not safe to be considered abandoned.
     * Abandoned state should probably be more carefully tracked via different
     * posInBlock signals or by checking mempool presence when necessary.
     */
    bool AddToWalletIfInvolvingMe(const CTransactionRef& tx, const uint256& block_hash, int posInBlock, bool fUpdate) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /* Mark a transaction (and its in-wallet descendants) as conflicting with a particular block. */
    void MarkConflicted(const uint256& hashBlock, const uint256& hashTx);

    /* Mark a transaction's inputs dirty, thus forcing the outputs to be recomputed */
    void MarkInputsDirty(const CTransactionRef& tx) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    void SyncMetaData(std::pair<TxSpends::iterator, TxSpends::iterator>) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /* Used by TransactionAddedToMemorypool/BlockConnected/Disconnected/ScanForWalletTransactions.
     * Should be called with non-zero block_hash and posInBlock if this is for a transaction that is included in a block. */
    void SyncTransaction(const CTransactionRef& tx, const uint256& block_hash, int posInBlock = 0, bool update_tx = true) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /* the HD chain data model (external chain counters) */
    CHDChain hdChain;

    /* HD derive new child key (on internal or external chain) */
    void DeriveNewChildKey(WalletBatch& batch, CKeyMetadata& metadata, CKey& secret, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    std::set<int64_t> setInternalKeyPool GUARDED_BY(cs_wallet);
    std::set<int64_t> setExternalKeyPool GUARDED_BY(cs_wallet);
    std::set<int64_t> set_pre_split_keypool GUARDED_BY(cs_wallet);
    int64_t m_max_keypool_index GUARDED_BY(cs_wallet) = 0;
    std::map<CKeyID, int64_t> m_pool_key_to_index;
    std::atomic<uint64_t> m_wallet_flags{0};

    int64_t nTimeFirstKey GUARDED_BY(cs_wallet) = 0;

    /**
     * Private version of AddWatchOnly method which does not accept a
     * timestamp, and which will reset the wallet's nTimeFirstKey value to 1 if
     * the watch key did not previously have a timestamp associated with it.
     * Because this is an inherited virtual method, it is accessible despite
     * being marked private, but it is marked private anyway to encourage use
     * of the other AddWatchOnly which accepts a timestamp and sets
     * nTimeFirstKey more intelligently for more efficient rescans.
     */
    bool AddWatchOnly(const CScript& dest) override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /** Interface for accessing chain state. */
    interfaces::Chain& m_chain;

    /** Wallet location which includes wallet name (see WalletLocation). */
    WalletLocation m_location;

    /** Internal database handle. */
    std::unique_ptr<WalletDatabase> database;

    /**
     * The following is used to keep track of how far behind the wallet is
     * from the chain sync, and to allow clients to block on us being caught up.
     *
     * Note that this is *not* how far we've processed, we may need some rescan
     * to have seen all transactions in the chain, but is only used to track
     * live BlockConnected callbacks.
     */
    uint256 m_last_block_processed;

public:
    /*
     * Main wallet lock.
     * This lock protects all the fields added by CWallet.
     */
    mutable CCriticalSection cs_wallet;

    /** Get database handle used by this wallet. Ideally this function would
     * not be necessary.
     */
    WalletDatabase& GetDBHandle()
    {
        return *database;
    }

    /**
     * Select a set of coins such that nValueRet >= nTargetValue and at least
     * all coins from coinControl are selected; Never select unconfirmed coins
     * if they are not ours
     */
    bool SelectCoins(const std::vector<COutput>& vAvailableCoins, const CAmount& nTargetValue, std::set<CInputCoin>& setCoinsRet, CAmount& nValueRet,
                    const CCoinControl& coin_control, CoinSelectionParams& coin_selection_params, bool& bnb_used) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    const WalletLocation& GetLocation() const { return m_location; }

    /** Get a name for this wallet for logging/debugging purposes.
     */
    const std::string& GetName() const { return m_location.GetName(); }

    void LoadKeyPool(int64_t nIndex, const CKeyPool &keypool) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void MarkPreSplitKeys() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    // Map from Key ID to key metadata.
    std::map<CKeyID, CKeyMetadata> mapKeyMetadata GUARDED_BY(cs_wallet);

    // Map from Script ID to key metadata (for watch-only keys).
    std::map<CScriptID, CKeyMetadata> m_script_metadata GUARDED_BY(cs_wallet);

    bool WriteKeyMetadata(const CKeyMetadata& meta, const CPubKey& pubkey, bool overwrite);

    typedef std::map<unsigned int, CMasterKey> MasterKeyMap;
    MasterKeyMap mapMasterKeys;
    unsigned int nMasterKeyMaxID = 0;

    /** Construct wallet with specified name and database implementation. */
    CWallet(interfaces::Chain& chain, const WalletLocation& location, std::unique_ptr<WalletDatabase> database) : m_chain(chain), m_location(location), database(std::move(database))
    {
    }

    ~CWallet()
    {
        // Should not have slots connected at this point.
        assert(NotifyUnload.empty());
        delete encrypted_batch;
        encrypted_batch = nullptr;
    }

    std::map<uint256, CWalletTx> mapWallet GUARDED_BY(cs_wallet);

    typedef std::multimap<int64_t, CWalletTx*> TxItems;
    TxItems wtxOrdered;

    int64_t nOrderPosNext GUARDED_BY(cs_wallet) = 0;
    uint64_t nAccountingEntryNumber = 0;

    std::map<CTxDestination, CAddressBookData> mapAddressBook GUARDED_BY(cs_wallet);

    std::set<COutPoint> setLockedCoins GUARDED_BY(cs_wallet);

    /** Registered interfaces::Chain::Notifications handler. */
    std::unique_ptr<interfaces::Handler> m_chain_notifications_handler;

    /** Interface for accessing chain state. */
    interfaces::Chain& chain() const { return m_chain; }

    const CWalletTx* GetWalletTx(const uint256& hash) const;

    //! check whether we are allowed to upgrade (or already support) to the named feature
    bool CanSupportFeature(enum WalletFeature wf) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); return nWalletMaxVersion >= wf; }

    /**
     * populate vCoins with vector of available COutputs.
     */
    void AvailableCoins(interfaces::Chain::Lock& locked_chain, std::vector<COutput>& vCoins, bool fOnlySafe=true, const CCoinControl *coinControl = nullptr, const CAmount& nMinimumAmount = 1, const CAmount& nMaximumAmount = MAX_MONEY, const CAmount& nMinimumSumAmount = MAX_MONEY, const uint64_t nMaximumCount = 0, const int nMinDepth = 0, const int nMaxDepth = 9999999) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /**
     * Return list of available coins and locked coins grouped by non-change output address.
     */
    std::map<CTxDestination, std::vector<COutput>> ListCoins(interfaces::Chain::Lock& locked_chain) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /**
     * Find non-change parent output.
     */
    const CTxOut& FindNonChangeParentOutput(const CTransaction& tx, int output) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /**
     * Shuffle and select coins until nTargetValue is reached while avoiding
     * small change; This method is stochastic for some inputs and upon
     * completion the coin set and corresponding actual target value is
     * assembled
     */
    bool SelectCoinsMinConf(const CAmount& nTargetValue, const CoinEligibilityFilter& eligibility_filter, std::vector<OutputGroup> groups,
        std::set<CInputCoin>& setCoinsRet, CAmount& nValueRet, const CoinSelectionParams& coin_selection_params, bool& bnb_used) const;

    bool IsSpent(interfaces::Chain::Lock& locked_chain, const uint256& hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    std::vector<OutputGroup> GroupOutputs(const std::vector<COutput>& outputs, bool single_coin) const;

    bool IsLockedCoin(uint256 hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void LockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void UnlockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void UnlockAllCoins() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void ListLockedCoins(std::vector<COutPoint>& vOutpts) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /*
     * Rescan abort properties
     */
    void AbortRescan() { fAbortRescan = true; }
    bool IsAbortingRescan() { return fAbortRescan; }
    bool IsScanning() { return fScanningWallet; }

    /**
     * keystore implementation
     * Generate a new key
     */
    CPubKey GenerateNewKey(WalletBatch& batch, bool internal = false) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Adds a key to the store, and saves it to disk.
    bool AddKeyPubKey(const CKey& key, const CPubKey &pubkey) override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    bool AddKeyPubKeyWithDB(WalletBatch &batch,const CKey& key, const CPubKey &pubkey) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Adds a key to the store, without saving it to disk (used by LoadWallet)
    bool LoadKey(const CKey& key, const CPubKey &pubkey) { return CCryptoKeyStore::AddKeyPubKey(key, pubkey); }
    //! Load metadata (used by LoadWallet)
    void LoadKeyMetadata(const CKeyID& keyID, const CKeyMetadata &metadata) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void LoadScriptMetadata(const CScriptID& script_id, const CKeyMetadata &metadata) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Upgrade stored CKeyMetadata objects to store key origin info as KeyOriginInfo
    void UpgradeKeyMetadata() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; nWalletMaxVersion = std::max(nWalletMaxVersion, nVersion); return true; }
    void UpdateTimeFirstKey(int64_t nCreateTime) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    //! Adds an encrypted key to the store, and saves it to disk.
    bool AddCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret) override;
    //! Adds an encrypted key to the store, without saving it to disk (used by LoadWallet)
    bool LoadCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret);
    bool AddCScript(const CScript& redeemScript) override;
    bool LoadCScript(const CScript& redeemScript);

    //! Adds a destination data tuple to the store, and saves it to disk
    bool AddDestData(const CTxDestination& dest, const std::string& key, const std::string& value) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Erases a destination data tuple in the store and on disk
    bool EraseDestData(const CTxDestination& dest, const std::string& key) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Adds a destination data tuple to the store, without saving it to disk
    void LoadDestData(const CTxDestination& dest, const std::string& key, const std::string& value) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Look up a destination data tuple in the store, return true if found false otherwise
    bool GetDestData(const CTxDestination& dest, const std::string& key, std::string* value) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Get all destination values matching a prefix.
    std::vector<std::string> GetDestValues(const std::string& prefix) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    //! Adds a watch-only address to the store, and saves it to disk.
    bool AddWatchOnly(const CScript& dest, int64_t nCreateTime) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    bool RemoveWatchOnly(const CScript &dest) override EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    //! Adds a watch-only address to the store, without saving it to disk (used by LoadWallet)
    bool LoadWatchOnly(const CScript &dest);

    //! Holds a timestamp at which point the wallet is scheduled (externally) to be relocked. Caller must arrange for actual relocking to occur via Lock().
    int64_t nRelockTime = 0;

    bool Unlock(const SecureString& strWalletPassphrase, bool accept_no_keys = false);
    bool ChangeWalletPassphrase(const SecureString& strOldWalletPassphrase, const SecureString& strNewWalletPassphrase);
    bool EncryptWallet(const SecureString& strWalletPassphrase);

    void GetKeyBirthTimes(interfaces::Chain::Lock& locked_chain, std::map<CTxDestination, int64_t> &mapKeyBirth) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    unsigned int ComputeTimeSmart(const CWalletTx& wtx) const;

    /**
     * Increment the next transaction order id
     * @return next transaction order id
     */
    int64_t IncOrderPosNext(WalletBatch *batch = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    DBErrors ReorderTransactions();

    void MarkDirty();
    bool AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose=true);
    void LoadToWallet(const CWalletTx& wtxIn) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void TransactionAddedToMempool(const CTransactionRef& tx) override;
    void BlockConnected(const CBlock& block, const std::vector<CTransactionRef>& vtxConflicted) override;
    void BlockDisconnected(const CBlock& block) override;
    void UpdatedBlockTip() override;
    int64_t RescanFromTime(int64_t startTime, const WalletRescanReserver& reserver, bool update);

    struct ScanResult {
        enum { SUCCESS, FAILURE, USER_ABORT } status = SUCCESS;

        //! Hash and height of most recent block that was successfully scanned.
        //! Unset if no blocks were scanned due to read errors or the chain
        //! being empty.
        uint256 last_scanned_block;
        Optional<int> last_scanned_height;

        //! Height of the most recent block that could not be scanned due to
        //! read errors or pruning. Will be set if status is FAILURE, unset if
        //! status is SUCCESS, and may or may not be set if status is
        //! USER_ABORT.
        uint256 last_failed_block;
    };
    ScanResult ScanForWalletTransactions(const uint256& first_block, const uint256& last_block, const WalletRescanReserver& reserver, bool fUpdate);
    void TransactionRemovedFromMempool(const CTransactionRef &ptx) override;
    void ReacceptWalletTransactions(interfaces::Chain::Lock& locked_chain) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    void ResendWalletTransactions();
    struct Balance {
        CAmount m_mine_trusted{0};           //!< Trusted, at depth=GetBalance.min_depth or more
        CAmount m_mine_untrusted_pending{0}; //!< Untrusted, but in mempool (pending)
        CAmount m_mine_immature{0};          //!< Immature coinbases in the main chain
        CAmount m_watchonly_trusted{0};
        CAmount m_watchonly_untrusted_pending{0};
        CAmount m_watchonly_immature{0};
    };
    Balance GetBalance(int min_depth = 0) const;
    CAmount GetAvailableBalance(const CCoinControl* coinControl = nullptr) const;

    OutputType TransactionChangeType(OutputType change_type, const std::vector<CRecipient>& vecSend);

    /**
     * Insert additional inputs into the transaction by
     * calling CreateTransaction();
     */
    bool FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nChangePosInOut, std::string& strFailReason, bool lockUnspents, const std::set<int>& setSubtractFeeFromOutputs, CCoinControl);
    bool SignTransaction(CMutableTransaction& tx) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    /**
     * Create a new transaction paying the recipients with a set of coins
     * selected by SelectCoins(); Also create the change output, when needed
     * @note passing nChangePosInOut as -1 will result in setting a random position
     */
    bool CreateTransaction(interfaces::Chain::Lock& locked_chain, const std::vector<CRecipient>& vecSend, CTransactionRef& tx, CReserveKey& reservekey, CAmount& nFeeRet, int& nChangePosInOut,
                           std::string& strFailReason, const CCoinControl& coin_control, bool sign = true);
    bool CommitTransaction(CTransactionRef tx, mapValue_t mapValue, std::vector<std::pair<std::string, std::string>> orderForm, CReserveKey& reservekey, CValidationState& state);

    bool DummySignTx(CMutableTransaction &txNew, const std::set<CTxOut> &txouts, bool use_max_sig = false) const
    {
        std::vector<CTxOut> v_txouts(txouts.size());
        std::copy(txouts.begin(), txouts.end(), v_txouts.begin());
        return DummySignTx(txNew, v_txouts, use_max_sig);
    }
    bool DummySignTx(CMutableTransaction &txNew, const std::vector<CTxOut> &txouts, bool use_max_sig = false) const;
    bool DummySignInput(CTxIn &tx_in, const CTxOut &txout, bool use_max_sig = false) const;

    CFeeRate m_pay_tx_fee{DEFAULT_PAY_TX_FEE};
    unsigned int m_confirm_target{DEFAULT_TX_CONFIRM_TARGET};
    bool m_spend_zero_conf_change{DEFAULT_SPEND_ZEROCONF_CHANGE};
    bool m_signal_rbf{DEFAULT_WALLET_RBF};
    bool m_allow_fallback_fee{true}; //!< will be defined via chainparams
    CFeeRate m_min_fee{DEFAULT_TRANSACTION_MINFEE}; //!< Override with -mintxfee
    /**
     * If fee estimation does not have enough data to provide estimates, use this fee instead.
     * Has no effect if not using fee estimation
     * Override with -fallbackfee
     */
    CFeeRate m_fallback_fee{DEFAULT_FALLBACK_FEE};
    CFeeRate m_discard_rate{DEFAULT_DISCARD_FEE};
    OutputType m_default_address_type{DEFAULT_ADDRESS_TYPE};
    OutputType m_default_change_type{DEFAULT_CHANGE_TYPE};

    bool NewKeyPool();
    size_t KeypoolCountExternalKeys() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    bool TopUpKeyPool(unsigned int kpSize = 0);
    void AddKeypoolPubkey(const CPubKey& pubkey, const bool internal);
    void AddKeypoolPubkeyWithDB(const CPubKey& pubkey, const bool internal, WalletBatch& batch);

    /**
     * Reserves a key from the keypool and sets nIndex to its index
     *
     * @param[out] nIndex the index of the key in keypool
     * @param[out] keypool the keypool the key was drawn from, which could be the
     *     the pre-split pool if present, or the internal or external pool
     * @param fRequestedInternal true if the caller would like the key drawn
     *     from the internal keypool, false if external is preferred
     *
     * @return true if succeeded, false if failed due to empty keypool
     * @throws std::runtime_error if keypool read failed, key was invalid,
     *     was not found in the wallet, or was misclassified in the internal
     *     or external keypool
     */
    bool ReserveKeyFromKeyPool(int64_t& nIndex, CKeyPool& keypool, bool fRequestedInternal);
    void KeepKey(int64_t nIndex);
    void ReturnKey(int64_t nIndex, bool fInternal, const CPubKey& pubkey);
    bool GetKeyFromPool(CPubKey &key, bool internal = false);
    int64_t GetOldestKeyPoolTime();
    /**
     * Marks all keys in the keypool up to and including reserve_key as used.
     */
    void MarkReserveKeysAsUsed(int64_t keypool_id) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    const std::map<CKeyID, int64_t>& GetAllReserveKeys() const { return m_pool_key_to_index; }

    std::set<std::set<CTxDestination>> GetAddressGroupings() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
    std::map<CTxDestination, CAmount> GetAddressBalances(interfaces::Chain::Lock& locked_chain);

    std::set<CTxDestination> GetLabelAddresses(const std::string& label) const;

    isminetype IsMine(const CTxIn& txin) const;
    /**
     * Returns amount of debit if the input matches the
     * filter, otherwise returns 0
     */
    CAmount GetDebit(const CTxIn& txin, const isminefilter& filter) const;
    isminetype IsMine(const CTxOut& txout) const;
    CAmount GetCredit(const CTxOut& txout, const isminefilter& filter) const;
    bool IsChange(const CTxOut& txout) const;
    bool IsChange(const CScript& script) const;
    CAmount GetChange(const CTxOut& txout) const;
    bool IsMine(const CTransaction& tx) const;
    /** should probably be renamed to IsRelevantToMe */
    bool IsFromMe(const CTransaction& tx) const;
    CAmount GetDebit(const CTransaction& tx, const isminefilter& filter) const;
    /** Returns whether all of the inputs match the filter */
    bool IsAllFromMe(const CTransaction& tx, const isminefilter& filter) const;
    CAmount GetCredit(const CTransaction& tx, const isminefilter& filter) const;
    CAmount GetChange(const CTransaction& tx) const;
    void ChainStateFlushed(const CBlockLocator& loc) override;

    DBErrors LoadWallet(bool& fFirstRunRet);
    DBErrors ZapWalletTx(std::vector<CWalletTx>& vWtx);
    DBErrors ZapSelectTx(std::vector<uint256>& vHashIn, std::vector<uint256>& vHashOut) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    bool SetAddressBook(const CTxDestination& address, const std::string& strName, const std::string& purpose);

    bool DelAddressBook(const CTxDestination& address);

    const std::string& GetLabelName(const CScript& scriptPubKey) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    unsigned int GetKeyPoolSize() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet)
    {
        AssertLockHeld(cs_wallet);
        return setInternalKeyPool.size() + setExternalKeyPool.size();
    }

    //! signify that a particular wallet feature is now used. this may change nWalletVersion and nWalletMaxVersion if those are lower
    void SetMinVersion(enum WalletFeature, WalletBatch* batch_in = nullptr, bool fExplicit = false);

    //! change which version we're allowed to upgrade to (note that this does not immediately imply upgrading to that format)
    bool SetMaxVersion(int nVersion);

    //! get the current wallet format (the oldest client version guaranteed to understand this wallet)
    int GetVersion() { LOCK(cs_wallet); return nWalletVersion; }

    //! Get wallet transactions that conflict with given transaction (spend same outputs)
    std::set<uint256> GetConflicts(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    //! Check if a given transaction has any of its outputs spent by another transaction in the wallet
    bool HasWalletSpend(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);

    //! Flush wallet (bitdb flush)
    void Flush(bool shutdown=false);

    /** Wallet is about to be unloaded */
    boost::signals2::signal<void ()> NotifyUnload;

    /**
     * Address book entry changed.
     * @note called with lock cs_wallet held.
     */
    boost::signals2::signal<void (CWallet *wallet, const CTxDestination
            &address, const std::string &label, bool isMine,
            const std::string &purpose,
            ChangeType status)> NotifyAddressBookChanged;

    /**
     * Wallet transaction added, removed or updated.
     * @note called with lock cs_wallet held.
     */
    boost::signals2::signal<void (CWallet *wallet, const uint256 &hashTx,
            ChangeType status)> NotifyTransactionChanged;

    /** Show progress e.g. for rescan */
    boost::signals2::signal<void (const std::string &title, int nProgress)> ShowProgress;

    /** Watch-only address added */
    boost::signals2::signal<void (bool fHaveWatchOnly)> NotifyWatchonlyChanged;

    /** Keypool has new keys */
    boost::signals2::signal<void ()> NotifyCanGetAddressesChanged;

    /** Inquire whether this wallet broadcasts transactions. */
    bool GetBroadcastTransactions() const { return fBroadcastTransactions; }
    /** Set whether this wallet broadcasts transactions. */
    void SetBroadcastTransactions(bool broadcast) { fBroadcastTransactions = broadcast; }

    /** Return whether transaction can be abandoned */
    bool TransactionCanBeAbandoned(const uint256& hashTx) const;

    /* Mark a transaction (and it in-wallet descendants) as abandoned so its inputs may be respent. */
    bool AbandonTransaction(interfaces::Chain::Lock& locked_chain, const uint256& hashTx);

    /** Mark a transaction as replaced by another transaction (e.g., BIP 125). */
    bool MarkReplaced(const uint256& originalHash, const uint256& newHash);

    //! Verify wallet naming and perform salvage on the wallet if required
    static bool Verify(interfaces::Chain& chain, const WalletLocation& location, bool salvage_wallet, std::string& error_string, std::string& warning_string);

    /* Initializes the wallet, returns a new CWallet instance or a null pointer in case of an error */
    static std::shared_ptr<CWallet> CreateWalletFromFile(interfaces::Chain& chain, const WalletLocation& location, uint64_t wallet_creation_flags = 0);

    /**
     * Wallet post-init setup
     * Gives the wallet a chance to register repetitive tasks and complete post-init tasks
     */
    void postInitProcess();

    bool BackupWallet(const std::string& strDest);

    /* Set the HD chain model (chain child index counters) */
    void SetHDChain(const CHDChain& chain, bool memonly);
    const CHDChain& GetHDChain() const { return hdChain; }

    /* Returns true if HD is enabled */
    bool IsHDEnabled() const;

    /* Returns true if the wallet can generate new keys */
    bool CanGenerateKeys();

    /* Returns true if the wallet can give out new addresses. This means it has keys in the keypool or can generate new keys */
    bool CanGetAddresses(bool internal = false);

    /* Generates a new HD seed (will not be activated) */
    CPubKey GenerateNewSeed();

    /* Derives a new HD seed (will not be activated) */
    CPubKey DeriveNewSeed(const CKey& key);

    /* Set the current HD seed (will reset the chain child index counters)
       Sets the seed's version based on the current wallet version (so the
       caller must ensure the current wallet version is correct before calling
       this function). */
    void SetHDSeed(const CPubKey& key);

    /**
     * Blocks until the wallet state is up-to-date to /at least/ the current
     * chain at the time this function is entered
     * Obviously holding cs_main/cs_wallet when going into this call may cause
     * deadlock
     */
    void BlockUntilSyncedToCurrentChain() LOCKS_EXCLUDED(cs_main, cs_wallet);

    /**
     * Explicitly make the wallet learn the related scripts for outputs to the
     * given key. This is purely to make the wallet file compatible with older
     * software, as CBasicKeyStore automatically does this implicitly for all
     * keys now.
     */
    void LearnRelatedScripts(const CPubKey& key, OutputType);

    /**
     * Same as LearnRelatedScripts, but when the OutputType is not known (and could
     * be anything).
     */
    void LearnAllRelatedScripts(const CPubKey& key);

    /** set a single wallet flag */
    void SetWalletFlag(uint64_t flags);

    /** Unsets a single wallet flag */
    void UnsetWalletFlag(uint64_t flag);

    /** check if a certain wallet flag is set */
    bool IsWalletFlagSet(uint64_t flag);

    /** overwrite all flags by the given uint64_t
       returns false if unknown, non-tolerable flags are present */
    bool SetWalletFlags(uint64_t overwriteFlags, bool memOnly);

    /** Returns a bracketed wallet name for displaying in logs, will return [default wallet] if the wallet has no name */
    const std::string GetDisplayName() const {
        std::string wallet_name = GetName().length() == 0 ? "default wallet" : GetName();
        return strprintf("[%s]", wallet_name);
    };

    /** Prepends the wallet name in logging output to ease debugging in multi-wallet use cases */
    template<typename... Params>
    void WalletLogPrintf(std::string fmt, Params... parameters) const {
        LogPrintf(("%s " + fmt).c_str(), GetDisplayName(), parameters...);
    };

    /** Implement lookup of key origin information through wallet key metadata. */
    bool GetKeyOrigin(const CKeyID& keyid, KeyOriginInfo& info) const override;

    /** Add a KeyOriginInfo to the wallet */
    bool AddKeyOrigin(const CPubKey& pubkey, const KeyOriginInfo& info);

    friend struct WalletTestingSetup;
};

/**
 * Called periodically by the schedule thread. Prompts individual wallets to resend
 * their transactions. Actual rebroadcast schedule is managed by the wallets themselves.
 */
void MaybeResendWalletTxs();

/** A key allocated from the key pool. */
class CReserveKey final : public CReserveScript
{
protected:
    CWallet* pwallet;
    int64_t nIndex{-1};
    CPubKey vchPubKey;
    bool fInternal{false};

public:
    explicit CReserveKey(CWallet* pwalletIn)
    {
        pwallet = pwalletIn;
    }

    CReserveKey(const CReserveKey&) = delete;
    CReserveKey& operator=(const CReserveKey&) = delete;

    ~CReserveKey()
    {
        ReturnKey();
    }

    void ReturnKey();
    bool GetReservedKey(CPubKey &pubkey, bool internal = false);
    void KeepKey();
    void KeepScript() override { KeepKey(); }
};

/** RAII object to check and reserve a wallet rescan */
class WalletRescanReserver
{
private:
    CWallet* m_wallet;
    bool m_could_reserve;
public:
    explicit WalletRescanReserver(CWallet* w) : m_wallet(w), m_could_reserve(false) {}

    bool reserve()
    {
        assert(!m_could_reserve);
        std::lock_guard<std::mutex> lock(m_wallet->mutexScanning);
        if (m_wallet->fScanningWallet) {
            return false;
        }
        m_wallet->fScanningWallet = true;
        m_could_reserve = true;
        return true;
    }

    bool isReserved() const
    {
        return (m_could_reserve && m_wallet->fScanningWallet);
    }

    ~WalletRescanReserver()
    {
        std::lock_guard<std::mutex> lock(m_wallet->mutexScanning);
        if (m_could_reserve) {
            m_wallet->fScanningWallet = false;
        }
    }
};

// Calculate the size of the transaction assuming all signatures are max size
// Use DummySignatureCreator, which inserts 71 byte signatures everywhere.
// NOTE: this requires that all inputs must be in mapWallet (eg the tx should
// be IsAllFromMe).
int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, bool use_max_sig = false) EXCLUSIVE_LOCKS_REQUIRED(wallet->cs_wallet);
int64_t CalculateMaximumSignedTxSize(const CTransaction &tx, const CWallet *wallet, const std::vector<CTxOut>& txouts, bool use_max_sig = false);
#endif // BITCOIN_WALLET_WALLET_H