Repository: bitcoin/bitcoin
File: src/node/mempool_args.cpp (C++)

Code before:
using common::AmountErrMsg;
using kernel::MemPoolLimits;
using kernel::MemPoolOptions;

namespace {
void ApplyArgsManOptions(const ArgsManager& argsman, MemPoolLimits& mempool_limits)
{
    mempool_limits.ancestor_count = argsman.GetIntArg("-limitancestorcount", mempool_limits.ancestor_count);

    if (auto vkb = argsman.GetIntArg("-limitancestorsize")) mempool_limits.ancestor_size_vbytes = *vkb * 1'000;

    mempool_limits.descendant_count = argsman.GetIntArg("-limitdescendantcount", mempool_limits.descendant_count);

    if (auto vkb = argsman.GetIntArg("-limitdescendantsize")) mempool_limits.descendant_size_vbytes = *vkb * 1'000;
}
}

util::Result<void> ApplyArgsManOptions(const ArgsManager& argsman, const CChainParams& chainparams, MemPoolOptions& mempool_opts)
{
    mempool_opts.check_ratio = argsman.GetIntArg("-checkmempool", mempool_opts.check_ratio);

    if (auto mb = argsman.GetIntArg("-maxmempool")) mempool_opts.max_size_bytes = *mb * 1'000'000;

    if (auto hours = argsman.GetIntArg("-mempoolexpiry")) mempool_opts.expiry = std::chrono::hours{*hours};

    // incremental relay fee sets the minimum feerate increase necessary for replacement in the mempool
    // and the amount the mempool min fee increases above the feerate of txs evicted due to mempool limiting.
    if (const auto arg{argsman.GetArg("-incrementalrelayfee")}) {
        if (std::optional<CAmount> inc_relay_fee = ParseMoney(*arg)) {
            mempool_opts.incremental_relay_feerate = CFeeRate{inc_relay_fee.value()};
        } else {
            return util::Error{AmountErrMsg("incrementalrelayfee", *arg)};
        }
    }

    if (const auto arg{argsman.GetArg("-minrelaytxfee")}) {
        if (std::optional<CAmount> min_relay_feerate = ParseMoney(*arg)) {
            // High fee check is done afterward in CWallet::Create()
            mempool_opts.min_relay_feerate = CFeeRate{min_relay_feerate.value()};
        } else {
            return util::Error{AmountErrMsg("minrelaytxfee", *arg)};
        }
    } else if (mempool_opts.incremental_relay_feerate > mempool_opts.min_relay_feerate) {
        // Allow only setting incremental fee to control both
        mempool_opts.min_relay_feerate = mempool_opts.incremental_relay_feerate;
        LogPrintf("Increasing minrelaytxfee to %s to match incrementalrelayfee\n", mempool_opts.min_relay_feerate.ToString());
    }

    // Feerate used to define dust.  Shouldn't be changed lightly as old
    // implementations may inadvertently create non-standard transactions
    if (const auto arg{argsman.GetArg("-dustrelayfee")}) {

Review comment (suggestion):
Maybe clarify this with something like:

```cpp
constexpr is_32bit{sizeof(void*) == 4};
```

Code after:
using common::AmountErrMsg;
using kernel::MemPoolLimits;
using kernel::MemPoolOptions;

//! Maximum mempool size on 32-bit systems.
static constexpr int MAX_32BIT_MEMPOOL_MB{500};

namespace {
void ApplyArgsManOptions(const ArgsManager& argsman, MemPoolLimits& mempool_limits)
{
    mempool_limits.ancestor_count = argsman.GetIntArg("-limitancestorcount", mempool_limits.ancestor_count);

    if (auto vkb = argsman.GetIntArg("-limitancestorsize")) mempool_limits.ancestor_size_vbytes = *vkb * 1'000;

    mempool_limits.descendant_count = argsman.GetIntArg("-limitdescendantcount", mempool_limits.descendant_count);

    if (auto vkb = argsman.GetIntArg("-limitdescendantsize")) mempool_limits.descendant_size_vbytes = *vkb * 1'000;
}
}

util::Result<void> ApplyArgsManOptions(const ArgsManager& argsman, const CChainParams& chainparams, MemPoolOptions& mempool_opts)
{
    mempool_opts.check_ratio = argsman.GetIntArg("-checkmempool", mempool_opts.check_ratio);

    if (auto mb = argsman.GetIntArg("-maxmempool")) {
        constexpr bool is_32bit{sizeof(void*) == 4};
        if (is_32bit && *mb > MAX_32BIT_MEMPOOL_MB) {
            return util::Error{Untranslated(strprintf("-maxmempool is set to %i but can't be over %i MB on 32-bit systems", *mb, MAX_32BIT_MEMPOOL_MB))};
        }
        mempool_opts.max_size_bytes = *mb * 1'000'000;
    }

    if (auto hours = argsman.GetIntArg("-mempoolexpiry")) mempool_opts.expiry = std::chrono::hours{*hours};

    // incremental relay fee sets the minimum feerate increase necessary for replacement in the mempool
    // and the amount the mempool min fee increases above the feerate of txs evicted due to mempool limiting.
    if (const auto arg{argsman.GetArg("-incrementalrelayfee")}) {
        if (std::optional<CAmount> inc_relay_fee = ParseMoney(*arg)) {
            mempool_opts.incremental_relay_feerate = CFeeRate{inc_relay_fee.value()};
        } else {
            return util::Error{AmountErrMsg("incrementalrelayfee", *arg)};
        }
    }

    if (const auto arg{argsman.GetArg("-minrelaytxfee")}) {
        if (std::optional<CAmount> min_relay_feerate = ParseMoney(*arg)) {
            // High fee check is done afterward in CWallet::Create()
            mempool_opts.min_relay_feerate = CFeeRate{min_relay_feerate.value()};
        } else {
            return util::Error{AmountErrMsg("minrelaytxfee", *arg)};
        }