package types import ( fmt "fmt" math "math" sdk "github.com/cosmos/cosmos-sdk/types" ) // ErrorNegativeGasConsumed defines an error thrown when the amount of gas refunded results in a // negative gas consumed amount. // Copied from cosmos-sdk type ErrorNegativeGasConsumed struct { Descriptor string } // ErrorGasOverflow defines an error thrown when an action results gas consumption // unsigned integer overflow. type ErrorGasOverflow struct { Descriptor string } type infiniteGasMeterWithLimit struct { consumed sdk.Gas limit sdk.Gas } // NewInfiniteGasMeterWithLimit returns a reference to a new infiniteGasMeter. func NewInfiniteGasMeterWithLimit(limit sdk.Gas) *infiniteGasMeterWithLimit { return &infiniteGasMeterWithLimit{ consumed: 0, limit: limit, } } func (g *infiniteGasMeterWithLimit) GasConsumed() sdk.Gas { return g.consumed } func (g *infiniteGasMeterWithLimit) GasConsumedToLimit() sdk.Gas { return g.consumed } func (g *infiniteGasMeterWithLimit) Limit() sdk.Gas { return g.limit } // GasRemaining returns the gas left in the GasMeter. func (g *infiniteGasMeterWithLimit) GasRemaining() sdk.Gas { if g.IsPastLimit() { return 0 } return g.limit - g.consumed } // addUint64Overflow performs the addition operation on two uint64 integers and // returns a boolean on whether or not the result overflows. func addUint64Overflow(a, b uint64) (uint64, bool) { if math.MaxUint64-a < b { return 0, true } return a + b, false } func (g *infiniteGasMeterWithLimit) ConsumeGas(amount sdk.Gas, descriptor string) { var overflow bool // TODO: Should we set the consumed field after overflow checking? g.consumed, overflow = addUint64Overflow(g.consumed, amount) if overflow { panic(ErrorGasOverflow{descriptor}) } } // RefundGas will deduct the given amount from the gas consumed. If the amount is greater than the // gas consumed, the function will panic. // // Use case: This functionality enables refunding gas to the trasaction or block gas pools so that // EVM-compatible chains can fully support the go-ethereum StateDb interface. // See https://github.com/cosmos/cosmos-sdk/pull/9403 for reference. func (g *infiniteGasMeterWithLimit) RefundGas(amount sdk.Gas, descriptor string) { if g.consumed < amount { panic(ErrorNegativeGasConsumed{Descriptor: descriptor}) } g.consumed -= amount } func (g *infiniteGasMeterWithLimit) IsPastLimit() bool { return false } func (g *infiniteGasMeterWithLimit) IsOutOfGas() bool { return false } func (g *infiniteGasMeterWithLimit) String() string { return fmt.Sprintf("InfiniteGasMeter:\n consumed: %d", g.consumed) }