package keeper import ( sdk "github.com/cosmos/cosmos-sdk/types" sdkerrors "github.com/cosmos/cosmos-sdk/types/errors" authante "github.com/cosmos/cosmos-sdk/x/auth/ante" "github.com/palantir/stacktrace" evmtypes "github.com/tharsis/ethermint/x/evm/types" "github.com/ethereum/go-ethereum/core" ethtypes "github.com/ethereum/go-ethereum/core/types" ) // AccountKeeper defines an expected keeper interface for the auth module's AccountKeeper // DeductTxCostsFromUserBalance it calculates the tx costs and deducts the fees func DeductTxCostsFromUserBalance( ctx sdk.Context, bankKeeper evmtypes.BankKeeper, accountKeeper evmtypes.AccountKeeper, msgEthTx evmtypes.MsgEthereumTx, txData evmtypes.TxData, denom string, homestead bool, istanbul bool, ) (sdk.Coins, error) { isContractCreation := txData.GetTo() == nil // fetch sender account from signature signerAcc, err := authante.GetSignerAcc(ctx, accountKeeper, msgEthTx.GetFrom()) if err != nil { return nil, stacktrace.Propagate(err, "account not found for sender %s", msgEthTx.From) } gasLimit := txData.GetGas() var accessList ethtypes.AccessList if txData.GetAccessList() != nil { accessList = txData.GetAccessList() } intrinsicGas, err := core.IntrinsicGas(txData.GetData(), accessList, isContractCreation, homestead, istanbul) if err != nil { return nil, stacktrace.Propagate(sdkerrors.Wrap( err, "failed to compute intrinsic gas cost"), "failed to retrieve intrinsic gas, contract creation = %t; homestead = %t, istanbul = %t", isContractCreation, homestead, istanbul, ) } // intrinsic gas verification during CheckTx if ctx.IsCheckTx() && gasLimit < intrinsicGas { return nil, sdkerrors.Wrapf( sdkerrors.ErrOutOfGas, "gas limit too low: %d (gas limit) < %d (intrinsic gas)", gasLimit, intrinsicGas, ) } // calculate the fees paid to validators based on gas limit and price feeAmt := txData.Fee() // fee = gas limit * gas price fees := sdk.Coins{sdk.NewCoin(denom, sdk.NewIntFromBigInt(feeAmt))} // deduct the full gas cost from the user balance if err := authante.DeductFees(bankKeeper, ctx, signerAcc, fees); err != nil { return nil, stacktrace.Propagate( err, "failed to deduct full gas cost %s from the user %s balance", fees, msgEthTx.From, ) } return fees, nil } // CheckSenderBalance validates sender has enough funds to pay for tx cost func CheckSenderBalance( ctx sdk.Context, bankKeeper evmtypes.BankKeeper, sender sdk.AccAddress, txData evmtypes.TxData, denom string, ) error { balance := bankKeeper.GetBalance(ctx, sender, denom) cost := txData.Cost() if balance.Amount.BigInt().Cmp(cost) < 0 { return stacktrace.Propagate( sdkerrors.Wrapf( sdkerrors.ErrInsufficientFunds, "sender balance < tx cost (%s < %s%s)", balance, txData.Cost(), denom, ), "sender should have had enough funds to pay for tx cost = fee + amount (%s = %s + %s)", cost, txData.Fee(), txData.GetValue(), ) } return nil }