transaction.h

// Copyright (c) 2021 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_TRANSACTION_H
#define BITCOIN_WALLET_TRANSACTION_H

#include <consensus/amount.h>
#include <primitives/transaction.h>
#include <serialize.h>
#include <wallet/ismine.h>
#include <threadsafety.h>
#include <tinyformat.h>
#include <util/strencodings.h>
#include <util/string.h>

#include <list>
#include <vector>

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

/** Legacy class used for deserializing vtxPrev for backwards compatibility.
 * vtxPrev was removed in commit 93a18a3650292afbb441a47d1fa1b94aeb0164e3,
 * but old wallet.dat files may still contain vtxPrev vectors of CMerkleTxs.
 * These need to get deserialized for field alignment when deserializing
 * a CWalletTx, but the deserialized values are discarded.**/
class CMerkleTx
{
public:
    template<typename Stream>
    void Unserialize(Stream& s)
    {
        CTransactionRef tx;
        uint256 hashBlock;
        std::vector<uint256> vMerkleBranch;
        int nIndex;

        s >> tx >> hashBlock >> vMerkleBranch >> nIndex;
    }
};

/**
 * 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
{
private:
    /** Constant used in hashBlock to indicate tx has been abandoned, only used at
     * serialization/deserialization to avoid ambiguity with conflicted.
     */
    static constexpr const uint256& ABANDON_HASH = uint256::ONE;

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.
     */
    bool fFromMe;
    int64_t nOrderPos; //!< position in ordered transaction list
    std::multimap<int64_t, CWalletTx*>::const_iterator m_it_wtxOrdered;

    // memory only
    enum AmountType { DEBIT, CREDIT, IMMATURE_CREDIT, AVAILABLE_CREDIT, AMOUNTTYPE_ENUM_ELEMENTS };
    mutable CachableAmount m_amounts[AMOUNTTYPE_ENUM_ELEMENTS];
    /**
     * This flag is true if all m_amounts caches are empty. This is particularly
     * useful in places where MarkDirty is conditionally called and the
     * condition can be expensive and thus can be skipped if the flag is true.
     * See MarkDestinationsDirty.
     */
    mutable bool m_is_cache_empty{true};
    mutable bool fChangeCached;
    mutable bool fInMempool;
    mutable CAmount nChangeCached;

    CWalletTx(CTransactionRef arg)
        : tx(std::move(arg))
    {
        Init();
    }

    void Init()
    {
        mapValue.clear();
        vOrderForm.clear();
        fTimeReceivedIsTxTime = false;
        nTimeReceived = 0;
        nTimeSmart = 0;
        fFromMe = false;
        fChangeCached = false;
        fInMempool = false;
        nChangeCached = 0;
        nOrderPos = -1;
        m_confirm = Confirmation{};
    }

    CTransactionRef tx;

    /** New transactions start as UNCONFIRMED. At BlockConnected,
     * they will transition to CONFIRMED. In case of reorg, at BlockDisconnected,
     * they roll back to UNCONFIRMED. If we detect a conflicting transaction at
     * block connection, we update conflicted tx and its dependencies as CONFLICTED.
     * If tx isn't confirmed and outside of mempool, the user may switch it to ABANDONED
     * by using the abandontransaction call. This last status may be override by a CONFLICTED
     * or CONFIRMED transition.
     */
    enum Status {
        UNCONFIRMED,
        CONFIRMED,
        CONFLICTED,
        ABANDONED
    };

    /** Confirmation includes tx status and a triplet of {block height/block hash/tx index in block}
     * at which tx has been confirmed. All three are set to 0 if tx is unconfirmed or abandoned.
     * Meaning of these fields changes with CONFLICTED state where they instead point to block hash
     * and block height of the deepest conflicting tx.
     */
    struct Confirmation {
        Status status;
        int block_height;
        uint256 hashBlock;
        int nIndex;
        Confirmation(Status status = UNCONFIRMED, int block_height = 0, uint256 block_hash = uint256(), int block_index = 0)
            : status{status}, block_height{block_height}, hashBlock{block_hash}, nIndex{block_index} {}
    };

    Confirmation m_confirm;

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

        mapValueCopy["fromaccount"] = "";
        if (nOrderPos != -1) {
            mapValueCopy["n"] = ToString(nOrderPos);
        }
        if (nTimeSmart) {
            mapValueCopy["timesmart"] = strprintf("%u", nTimeSmart);
        }

        std::vector<uint8_t> dummy_vector1; //!< Used to be vMerkleBranch
        std::vector<uint8_t> dummy_vector2; //!< Used to be vtxPrev
        bool dummy_bool = false; //!< Used to be fSpent
        uint256 serializedHash = isAbandoned() ? ABANDON_HASH : m_confirm.hashBlock;
        int serializedIndex = isAbandoned() || isConflicted() ? -1 : m_confirm.nIndex;
        s << tx << serializedHash << dummy_vector1 << serializedIndex << dummy_vector2 << mapValueCopy << vOrderForm << fTimeReceivedIsTxTime << nTimeReceived << fFromMe << dummy_bool;
    }

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

        std::vector<uint256> dummy_vector1; //!< Used to be vMerkleBranch
        std::vector<CMerkleTx> dummy_vector2; //!< Used to be vtxPrev
        bool dummy_bool; //! Used to be fSpent
        int serializedIndex;
        s >> tx >> m_confirm.hashBlock >> dummy_vector1 >> serializedIndex >> dummy_vector2 >> mapValue >> vOrderForm >> fTimeReceivedIsTxTime >> nTimeReceived >> fFromMe >> dummy_bool;

        /* At serialization/deserialization, an nIndex == -1 means that hashBlock refers to
         * the earliest block in the chain we know this or any in-wallet ancestor conflicts
         * with. If nIndex == -1 and hashBlock is ABANDON_HASH, it means transaction is abandoned.
         * In same context, an nIndex >= 0 refers to a confirmed transaction (if hashBlock set) or
         * unconfirmed one. Older clients interpret nIndex == -1 as unconfirmed for backward
         * compatibility (pre-commit 9ac63d6).
         */
        if (serializedIndex == -1 && m_confirm.hashBlock == ABANDON_HASH) {
            setAbandoned();
        } else if (serializedIndex == -1) {
            setConflicted();
        } else if (!m_confirm.hashBlock.IsNull()) {
            m_confirm.nIndex = serializedIndex;
            setConfirmed();
        }

        const auto it_op = mapValue.find("n");
        nOrderPos = (it_op != mapValue.end()) ? LocaleIndependentAtoi<int64_t>(it_op->second) : -1;
        const auto it_ts = mapValue.find("timesmart");
        nTimeSmart = (it_ts != mapValue.end()) ? static_cast<unsigned int>(LocaleIndependentAtoi<int64_t>(it_ts->second)) : 0;

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

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

    //! make sure balances are recalculated
    void MarkDirty()
    {
        m_amounts[DEBIT].Reset();
        m_amounts[CREDIT].Reset();
        m_amounts[IMMATURE_CREDIT].Reset();
        m_amounts[AVAILABLE_CREDIT].Reset();
        fChangeCached = false;
        m_is_cache_empty = true;
    }

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

    bool InMempool() const;

    int64_t GetTxTime() const;

    bool isAbandoned() const { return m_confirm.status == CWalletTx::ABANDONED; }
    void setAbandoned()
    {
        m_confirm.status = CWalletTx::ABANDONED;
        m_confirm.hashBlock = uint256();
        m_confirm.block_height = 0;
        m_confirm.nIndex = 0;
    }
    bool isConflicted() const { return m_confirm.status == CWalletTx::CONFLICTED; }
    void setConflicted() { m_confirm.status = CWalletTx::CONFLICTED; }
    bool isUnconfirmed() const { return m_confirm.status == CWalletTx::UNCONFIRMED; }
    void setUnconfirmed() { m_confirm.status = CWalletTx::UNCONFIRMED; }
    bool isConfirmed() const { return m_confirm.status == CWalletTx::CONFIRMED; }
    void setConfirmed() { m_confirm.status = CWalletTx::CONFIRMED; }
    const uint256& GetHash() const { return tx->GetHash(); }
    bool IsCoinBase() const { return tx->IsCoinBase(); }

    // Disable copying of CWalletTx objects to prevent bugs where instances get
    // copied in and out of the mapWallet map, and fields are updated in the
    // wrong copy.
    CWalletTx(CWalletTx const &) = delete;
    void operator=(CWalletTx const &x) = delete;
};

#endif // BITCOIN_WALLET_TRANSACTION_H