package keeper import ( "fmt" errorsmod "cosmossdk.io/errors" sdkmath "cosmossdk.io/math" sdk "github.com/cosmos/cosmos-sdk/types" sdkerrors "github.com/cosmos/cosmos-sdk/types/errors" evmtypes "github.com/evmos/ethermint/x/evm/types" "github.com/0glabs/0g-chain/x/evmutil/types" ) const ( // EvmDenom is the gas denom used by the evm EvmDenom = "neuron" // CosmosDenom is the gas denom used by the 0g-chain app CosmosDenom = "ua0gi" ) // ConversionMultiplier is the conversion multiplier between neuron and ua0gi var ConversionMultiplier = sdkmath.NewInt(1_000_000_000_000) var _ evmtypes.BankKeeper = EvmBankKeeper{} // EvmBankKeeper is a BankKeeper wrapper for the x/evm module to allow the use // of the 18 decimal neuron coin on the evm. // x/evm consumes gas and send coins by minting and burning neuron coins in its module // account and then sending the funds to the target account. // This keeper uses both the a0gi coin and a separate neuron balance to manage the // extra percision needed by the evm. type EvmBankKeeper struct { neuronKeeper Keeper bk types.BankKeeper ak types.AccountKeeper } func NewEvmBankKeeper(neuronKeeper Keeper, bk types.BankKeeper, ak types.AccountKeeper) EvmBankKeeper { return EvmBankKeeper{ neuronKeeper: neuronKeeper, bk: bk, ak: ak, } } // GetBalance returns the total **spendable** balance of neuron for a given account by address. func (k EvmBankKeeper) GetBalance(ctx sdk.Context, addr sdk.AccAddress, denom string) sdk.Coin { if denom != EvmDenom { panic(fmt.Errorf("only evm denom %s is supported by EvmBankKeeper", EvmDenom)) } spendableCoins := k.bk.SpendableCoins(ctx, addr) ua0gi := spendableCoins.AmountOf(CosmosDenom) neuron := k.neuronKeeper.GetBalance(ctx, addr) total := ua0gi.Mul(ConversionMultiplier).Add(neuron) return sdk.NewCoin(EvmDenom, total) } // SendCoins transfers neuron coins from a AccAddress to an AccAddress. func (k EvmBankKeeper) SendCoins(ctx sdk.Context, senderAddr sdk.AccAddress, recipientAddr sdk.AccAddress, amt sdk.Coins) error { // SendCoins method is not used by the evm module, but is required by the // evmtypes.BankKeeper interface. This must be updated if the evm module // is updated to use SendCoins. panic("not implemented") } // SendCoinsFromModuleToAccount transfers neuron coins from a ModuleAccount to an AccAddress. // It will panic if the module account does not exist. An error is returned if the recipient // address is black-listed or if sending the tokens fails. func (k EvmBankKeeper) SendCoinsFromModuleToAccount(ctx sdk.Context, senderModule string, recipientAddr sdk.AccAddress, amt sdk.Coins) error { ua0gi, neuron, err := SplitNeuronCoins(amt) if err != nil { return err } if ua0gi.Amount.IsPositive() { if err := k.bk.SendCoinsFromModuleToAccount(ctx, senderModule, recipientAddr, sdk.NewCoins(ua0gi)); err != nil { return err } } senderAddr := k.GetModuleAddress(senderModule) if err := k.ConvertOneUa0giToNeuronIfNeeded(ctx, senderAddr, neuron); err != nil { return err } if err := k.neuronKeeper.SendBalance(ctx, senderAddr, recipientAddr, neuron); err != nil { return err } return k.ConvertNeuronToUa0gi(ctx, recipientAddr) } // SendCoinsFromAccountToModule transfers neuron coins from an AccAddress to a ModuleAccount. // It will panic if the module account does not exist. func (k EvmBankKeeper) SendCoinsFromAccountToModule(ctx sdk.Context, senderAddr sdk.AccAddress, recipientModule string, amt sdk.Coins) error { ua0gi, neuronNeeded, err := SplitNeuronCoins(amt) if err != nil { return err } if ua0gi.IsPositive() { if err := k.bk.SendCoinsFromAccountToModule(ctx, senderAddr, recipientModule, sdk.NewCoins(ua0gi)); err != nil { return err } } if err := k.ConvertOneUa0giToNeuronIfNeeded(ctx, senderAddr, neuronNeeded); err != nil { return err } recipientAddr := k.GetModuleAddress(recipientModule) if err := k.neuronKeeper.SendBalance(ctx, senderAddr, recipientAddr, neuronNeeded); err != nil { return err } return k.ConvertNeuronToUa0gi(ctx, recipientAddr) } // MintCoins mints neuron coins by minting the equivalent a0gi coins and any remaining neuron coins. // It will panic if the module account does not exist or is unauthorized. func (k EvmBankKeeper) MintCoins(ctx sdk.Context, moduleName string, amt sdk.Coins) error { ua0gi, neuron, err := SplitNeuronCoins(amt) if err != nil { return err } if ua0gi.IsPositive() { if err := k.bk.MintCoins(ctx, moduleName, sdk.NewCoins(ua0gi)); err != nil { return err } } recipientAddr := k.GetModuleAddress(moduleName) if err := k.neuronKeeper.AddBalance(ctx, recipientAddr, neuron); err != nil { return err } return k.ConvertNeuronToUa0gi(ctx, recipientAddr) } // BurnCoins burns neuron coins by burning the equivalent a0gi coins and any remaining neuron coins. // It will panic if the module account does not exist or is unauthorized. func (k EvmBankKeeper) BurnCoins(ctx sdk.Context, moduleName string, amt sdk.Coins) error { ua0gi, neuron, err := SplitNeuronCoins(amt) if err != nil { return err } if ua0gi.IsPositive() { if err := k.bk.BurnCoins(ctx, moduleName, sdk.NewCoins(ua0gi)); err != nil { return err } } moduleAddr := k.GetModuleAddress(moduleName) if err := k.ConvertOneUa0giToNeuronIfNeeded(ctx, moduleAddr, neuron); err != nil { return err } return k.neuronKeeper.RemoveBalance(ctx, moduleAddr, neuron) } // ConvertOneUa0giToNeuronIfNeeded converts 1 a0gi to neuron for an address if // its neuron balance is smaller than the neuronNeeded amount. func (k EvmBankKeeper) ConvertOneUa0giToNeuronIfNeeded(ctx sdk.Context, addr sdk.AccAddress, neuronNeeded sdkmath.Int) error { neuronBal := k.neuronKeeper.GetBalance(ctx, addr) if neuronBal.GTE(neuronNeeded) { return nil } ua0giToStore := sdk.NewCoins(sdk.NewCoin(CosmosDenom, sdk.OneInt())) if err := k.bk.SendCoinsFromAccountToModule(ctx, addr, types.ModuleName, ua0giToStore); err != nil { return err } // add 1a0gi equivalent of neuron to addr neuronToReceive := ConversionMultiplier if err := k.neuronKeeper.AddBalance(ctx, addr, neuronToReceive); err != nil { return err } return nil } // ConvertNeuronToA0gi converts all available neuron to a0gi for a given AccAddress. func (k EvmBankKeeper) ConvertNeuronToUa0gi(ctx sdk.Context, addr sdk.AccAddress) error { totalNeuron := k.neuronKeeper.GetBalance(ctx, addr) ua0gi, _, err := SplitNeuronCoins(sdk.NewCoins(sdk.NewCoin(EvmDenom, totalNeuron))) if err != nil { return err } // do nothing if account does not have enough neuron for a single a0gi ua0giToReceive := ua0gi.Amount if !ua0giToReceive.IsPositive() { return nil } // remove neuron used for converting to ua0gi neuronToBurn := ua0giToReceive.Mul(ConversionMultiplier) finalBal := totalNeuron.Sub(neuronToBurn) if err := k.neuronKeeper.SetBalance(ctx, addr, finalBal); err != nil { return err } fromAddr := k.GetModuleAddress(types.ModuleName) if err := k.bk.SendCoins(ctx, fromAddr, addr, sdk.NewCoins(ua0gi)); err != nil { return err } return nil } func (k EvmBankKeeper) GetModuleAddress(moduleName string) sdk.AccAddress { addr := k.ak.GetModuleAddress(moduleName) if addr == nil { panic(errorsmod.Wrapf(sdkerrors.ErrUnknownAddress, "module account %s does not exist", moduleName)) } return addr } // SplitNeuronCoins splits neuron coins to the equivalent a0gi coins and any remaining neuron balance. // An error will be returned if the coins are not valid or if the coins are not the neuron denom. func SplitNeuronCoins(coins sdk.Coins) (sdk.Coin, sdkmath.Int, error) { neuron := sdk.ZeroInt() ua0gi := sdk.NewCoin(CosmosDenom, sdk.ZeroInt()) if len(coins) == 0 { return ua0gi, neuron, nil } if err := ValidateEvmCoins(coins); err != nil { return ua0gi, neuron, err } // note: we should always have len(coins) == 1 here since coins cannot have dup denoms after we validate. coin := coins[0] remainingBalance := coin.Amount.Mod(ConversionMultiplier) if remainingBalance.IsPositive() { neuron = remainingBalance } ua0giAmount := coin.Amount.Quo(ConversionMultiplier) if ua0giAmount.IsPositive() { ua0gi = sdk.NewCoin(CosmosDenom, ua0giAmount) } return ua0gi, neuron, nil } // ValidateEvmCoins validates the coins from evm is valid and is the EvmDenom (neuron). func ValidateEvmCoins(coins sdk.Coins) error { if len(coins) == 0 { return nil } // validate that coins are non-negative, sorted, and no dup denoms if err := coins.Validate(); err != nil { return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, coins.String()) } // validate that coin denom is neuron if len(coins) != 1 || coins[0].Denom != EvmDenom { errMsg := fmt.Sprintf("invalid evm coin denom, only %s is supported", EvmDenom) return errorsmod.Wrap(sdkerrors.ErrInvalidCoins, errMsg) } return nil }