utils.go

package evm

import (
	"math/big"

	gethcommon "github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/obscuronet/go-obscuro/go/common"
	"github.com/obscuronet/go-obscuro/go/enclave/crypto"
)

// Perform the conversion between an Obscuro header and an Ethereum header that the EVM understands
// in the first stage we just encode the obscuro header in the Extra field
// todo - find a better way
func convertToEthHeader(h *common.BatchHeader, secret []byte) (*types.Header, error) {
	obscuroHeader, err := rlp.EncodeToBytes(h)
	if err != nil {
		return nil, err
	}

	// deterministically calculate private randomness that will be exposed to the evm
	randomness := crypto.PrivateRollupRnd(h.MixDigest.Bytes(), secret)

	return &types.Header{
		ParentHash:  h.ParentHash,
		Root:        h.Root,
		TxHash:      h.TxHash,
		ReceiptHash: h.ReceiptHash,
		Bloom:       h.Bloom,
		Difficulty:  big.NewInt(0).SetBytes(randomness),
		Number:      h.Number,
		GasLimit:    1_000_000_000,
		GasUsed:     0,
		Time:        h.Time,
		Extra:       obscuroHeader,
		MixDigest:   gethcommon.BytesToHash(randomness),
		Nonce:       types.BlockNonce{},
		BaseFee:     gethcommon.Big0,
	}, nil
}

/*
func convertFromEthHeader(header *types.Header) *common.Header {
	h := new(common.Header)
	err := rlp.DecodeBytes(header.Extra, h)
	if err != nil {
		panic(err)
	}
	return h
}
*/