Function dumptxoutset

src/rpc/blockchain.cpp:2951–2999

* Serialize the UTXO set to a file for loading elsewhere. * * @see SnapshotMetadata */

 * @see SnapshotMetadata
 */
static RPCHelpMan dumptxoutset()
{
    return RPCHelpMan{
        "dumptxoutset",
        "Write the serialized UTXO set to disk.",
        {
            {"path", RPCArg::Type::STR, RPCArg::Optional::NO, "Path to the output file. If relative, will be prefixed by datadir."},
        },
        RPCResult{
            RPCResult::Type::OBJ, "", "",
                {
                    {RPCResult::Type::NUM, "coins_written", "the number of coins written in the snapshot"},
                    {RPCResult::Type::STR_HEX, "base_hash", "the hash of the base of the snapshot"},
                    {RPCResult::Type::NUM, "base_height", "the height of the base of the snapshot"},
                    {RPCResult::Type::STR, "path", "the absolute path that the snapshot was written to"},
                    {RPCResult::Type::STR_HEX, "txoutset_hash", "the hash of the UTXO set contents"},
                    {RPCResult::Type::NUM, "nchaintx", "the number of transactions in the chain up to and including the base block"},
                }
        },
        RPCExamples{
            HelpExampleCli("dumptxoutset", "utxo.dat")
        },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    const ArgsManager& args{EnsureAnyArgsman(request.context)};
    const fs::path path = fsbridge::AbsPathJoin(args.GetDataDirNet(), fs::u8path(request.params[0].get_str()));
    // Write to a temporary path and then move into `path` on completion
    // to avoid confusion due to an interruption.
    const fs::path temppath = fsbridge::AbsPathJoin(args.GetDataDirNet(), fs::u8path(request.params[0].get_str() + ".incomplete"));

    if (fs::exists(path)) {
        throw JSONRPCError(
            RPC_INVALID_PARAMETER,
            path.u8string() + " already exists. If you are sure this is what you want, "
            "move it out of the way first");
    }

    FILE* file{fsbridge::fopen(temppath, "wb")};
    CAutoFile afile{file, SER_DISK, CLIENT_VERSION};
    NodeContext& node = EnsureAnyNodeContext(request.context);
    UniValue result = CreateUTXOSnapshot(
        node, node.chainman->ActiveChainstate(), afile, path, temppath);
    fs::rename(temppath, path);

    result.pushKV("path", path.u8string());
    return result;
},
    };
}

UniValue CreateUTXOSnapshot(
    NodeContext& node,