Function SignStep

src/script/sign.cpp:95–163

* Sign scriptPubKey using signature made with creator. * Signatures are returned in scriptSigRet (or returns false if scriptPubKey can't be signed), * unless whichTypeRet is TX_SCRIPTHASH, in which case scriptSigRet is the redemption script. * Returns false if scriptPubKey could not be completely satisfied. */

 * Returns false if scriptPubKey could not be completely satisfied.
 */
static bool SignStep(const SigningProvider& provider, const BaseSignatureCreator& creator, const CScript& scriptPubKey,
                     std::vector<valtype>& ret, txnouttype& whichTypeRet, SigVersion sigversion, SignatureData& sigdata)
{
    CScript scriptRet;
    uint160 h160;
    ret.clear();
    std::vector<unsigned char> sig;

    std::vector<valtype> vSolutions;
    if (!Solver(scriptPubKey, whichTypeRet, vSolutions))
        return false;

    switch (whichTypeRet)
    {
    case TX_NONSTANDARD:
    case TX_NULL_DATA:
    case TX_WITNESS_UNKNOWN:
        return false;
    case TX_PUBKEY:
        if (!CreateSig(creator, sigdata, provider, sig, CPubKey(vSolutions[0]), scriptPubKey, sigversion)) return false;
        ret.push_back(std::move(sig));
        return true;
    case TX_PUBKEYHASH: {
        CKeyID keyID = CKeyID(uint160(vSolutions[0]));
        CPubKey pubkey;
        GetPubKey(provider, sigdata, keyID, pubkey);
        if (!CreateSig(creator, sigdata, provider, sig, pubkey, scriptPubKey, sigversion)) return false;
        ret.push_back(std::move(sig));
        ret.push_back(ToByteVector(pubkey));
        return true;
    }
    case TX_SCRIPTHASH:
        if (GetCScript(provider, sigdata, uint160(vSolutions[0]), scriptRet)) {
            ret.push_back(std::vector<unsigned char>(scriptRet.begin(), scriptRet.end()));
            return true;
        }
        return false;

    case TX_MULTISIG: {
        size_t required = vSolutions.front()[0];
        ret.push_back(valtype()); // workaround CHECKMULTISIG bug
        for (size_t i = 1; i < vSolutions.size() - 1; ++i) {
            CPubKey pubkey = CPubKey(vSolutions[i]);
            if (ret.size() < required + 1 && CreateSig(creator, sigdata, provider, sig, pubkey, scriptPubKey, sigversion)) {
                ret.push_back(std::move(sig));
            }
        }
        bool ok = ret.size() == required + 1;
        for (size_t i = 0; i + ret.size() < required + 1; ++i) {
            ret.push_back(valtype());
        }
        return ok;
    }
    case TX_WITNESS_V0_KEYHASH:
        ret.push_back(vSolutions[0]);
        return true;

    case TX_WITNESS_V0_SCRIPTHASH: