Cosmos 普通交易手续费调

key = WriteCostPerByte * len(key)
value = WriteCostPerByte * len(value)

keyGas = ReadCostPerByte * len(key)
valueGas = ReadCostPerByte * len(value)

// GasMeter interface to track gas consumption
 type GasMeter interface {
 GasConsumed() Gas
 GasConsumedToLimit() Gas
 GasRemaining() Gas
 Limit() Gas
 ConsumeGas(amount Gas, descriptor string)
 RefundGas(amount Gas, descriptor string)
 IsPastLimit() bool
 IsOutOfGas() bool
 String() string
}

// Implements KVStore.
func (gs *Store) Get(key []byte) (value []byte) {
    gs.gasMeter.ConsumeGas(gs.gasConfig.ReadCostFlat, types.GasReadCostFlatDesc)
    // parent 是 types.KVStore，即数据库接口
    value = gs.parent.Get(key)

    // TODO overflow-safe math?
    // 对读的操作，记录到 gasMeter 中
    gs.gasMeter.ConsumeGas(gs.gasConfig.ReadCostPerByte*types.Gas(len(key)), types.GasReadPerByteDesc)
    gs.gasMeter.ConsumeGas(gs.gasConfig.ReadCostPerByte*types.Gas(len(value)), types.GasReadPerByteDesc)
    return value
 }

// Implements KVStore.
func (gs *Store) Set(key, value []byte) {
    types.AssertValidKey(key)
    types.AssertValidValue(value)
    gs.gasMeter.ConsumeGas(gs.gasConfig.WriteCostFlat, types.GasWriteCostFlatDesc)

    // TODO overflow-safe math?
    gs.gasMeter.ConsumeGas(gs.gasConfig.WriteCostPerByte*types.Gas(len(key)), types.GasWritePerByteDesc)
    gs.gasMeter.ConsumeGas(gs.gasConfig.WriteCostPerByte*types.Gas(len(value)), types.GasWritePerByteDesc)
    gs.parent.Set(key, value) 
}

func (cgts ConsumeTxSizeGasDecorator) AnteHandle(ctx sdk.Context, tx sdk.Tx, simulate bool, next sdk.AnteHandler) (sdk.Context, error) {
    sigTx, ok := tx.(authsigning.SigVerifiableTx)
    if !ok {
        return ctx, errorsmod.Wrap(sdkerrors.ErrTxDecode, "invalid tx type")
    }
    params := cgts.ak.GetParams(ctx)
    // 计算交易长度
    // ctx: transaction 交易上下文
    // 注意，此处跟踪原始交易 byte 长度
    ctx.GasMeter().ConsumeGas(params.TxSizeCostPerByte*storetypes.Gas(len(ctx.TxBytes())), "txSize")
    // simulate gas cost for signatures in simulate mode
    // 在模拟模式下模拟签名的gas成本
    if simulate {
        // in simulate mode, each element should be a nil signature
        // 在模拟模式下，每个元素都应是 nil 签名 
        sigs, err := sigTx.GetSignaturesV2()
        if err != nil {
            return ctx, err
        } n := len(sigs) signers, err := sigTx.GetSigners() if err != nil { return sdk.Context{}, err }
        for i, signer := range signers {
            // if signature is already filled in, no need to simulate gas cost
            // 如果签名已填写，则无需模拟gas成本
            if i < n && !isIncompleteSignature(sigs[i].Data) {
                continue
            }
            var pubkey cryptotypes.PubKey
            acc := cgts.ak.GetAccount(ctx, signer)

            // use placeholder simSecp256k1Pubkey
            if sig is nil if acc == nil || acc.GetPubKey() == nil {
                pubkey = simSecp256k1Pubkey 
            } else {
                pubkey = acc.GetPubKey()
            }
            // use stdsignature to mock the size of a full signature
            // 使用 stdsignature 模拟完整签名的大小
            simSig := legacytx.StdSignature{ //nolint:staticcheck // SA1019: legacytx.StdSignature is deprecated 
                Signature: simSecp256k1Sig[:],
                PubKey: pubkey,
            }
            sigBz := legacy.Cdc.MustMarshal(simSig)
            // cost 为签名长度
            cost := storetypes.Gas(len(sigBz) + 6)
            // If the pubkey is a multi-signature pubkey, then we estimate for the maximum
            // number of signers. 
            // 如果公开密钥是多签名公开密钥，那么我们将估计最大的签名者数量。 
            if _, ok := pubkey.(*multisig.LegacyAminoPubKey); ok {
                cost *= params.TxSigLimit
            } 
            // 此处记录 签名后的 gas 消耗
            ctx.GasMeter().ConsumeGas(params.TxSizeCostPerByte*cost, "txSize") 
        }
    }
    return next(ctx, tx, simulate)
}