KIP-8: EVM¶
| Author | iavl(@NetCloth) |
|---|---|
| Status | Draft |
| Type | Standard Track |
| Category | Core |
| Created | 2020-6-22 |
1. Summary¶
This KIP is about introducing EVM for OKExChain to support running smart contracts.
2. Abstract¶
This KIP defines transactions and messages to support running smart contracts on OKExChain.
3. Status¶
Open Source Repository: https://github.com/iavl/okexchain
Docs: https://github.com/iavl/okexchain/tree/iavl-evm/docs/evm
4. Motivation¶
As the underlying runtime environment of smart contracts, EVM is currently the most mature virtual machine running on the blockchain.
Running smart contracts is one of OKExChain’s ecological directions.
The KIP is to conclude the target, to realize self-operation in the era of blockchain.
5. Specification¶
5.1 Message Structures¶
The creation and call of contracts message structure：
type MsgContract struct {
From sdk.AccAddress `json:"from" yaml:"from"`
To sdk.AccAddress `json:"to" yaml:"to"`
Payload hexutil.Bytes `json:"payload" yaml:"payload"`
Amount sdk.Coin `json:"amount" yaml:"amount"`
}
Creation¶
When the TO field in the MsgContract structure is nil, it means that this is a creation message.
Call¶
When the TO field in the MsgContract structure is an address, it means that this is a call message.
Contract Definition¶
Contract is a structure used by EVM to execute (virtual machine) instructions.
Whether it is the creation or call of a contract, the handler will first construct it into a contract structure, and then put into the EVM to execute
type Contract struct {
CallerAddress sdk.AccAddress
caller ContractRef
self ContractRef
jumpdests map[sdk.Hash]bitvec // Aggregated result of JUMPDEST analysis.
analysis bitvec // Locally cached result of JUMPDEST analysis
Code []byte
CodeHash sdk.Hash
CodeAddr *sdk.AccAddress
Input []byte
Gas uint64
value *big.Int
}
5.2 Process¶
handleMsgContract is a transaction handler in module which preforms state transition on the state machine.
func handleMsgContract(ctx sdk.Context, msg MsgContract, k Keeper) (sdk.Result) {
// validate msg
err := msg.ValidateBasic()
if err != nil {
return nil, err
}
// state transition
res, err := DoStateTransition(ctx, msg, k, ctx.Simulate)
if err != nil {
return err
}
// emite event
ctx.EventManager().EmitEvent(
sdk.NewEvent(
sdk.EventTypeMessage,
sdk.NewAttribute(sdk.AttributeKeyModule, types.AttributeValueCategory),
),
)
return sdk.Result{Data: res.Data, GasUsed: res.GasUsed, Events: ctx.EventManager().Events()}
}