forked from hyperledger-archives/burrow
/
decoder.go
56 lines (46 loc) · 1.6 KB
/
decoder.go
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package service
import (
"fmt"
"math/big"
"github.com/hyperledger/burrow/crypto"
"github.com/hyperledger/burrow/execution/evm/abi"
"github.com/hyperledger/burrow/execution/exec"
"github.com/hyperledger/burrow/vent/types"
"github.com/pkg/errors"
)
// decodeEvent unpacks & decodes event data
func decodeEvent(header *exec.Header, log *exec.LogEvent, abiSpec *abi.AbiSpec) (map[string]interface{}, error) {
// to prepare decoded data and map to event item name
data := make(map[string]interface{})
var eventID abi.EventID
copy(eventID[:], log.Topics[0].Bytes())
evAbi, ok := abiSpec.EventsById[eventID]
if !ok {
return nil, fmt.Errorf("Abi spec not found for event %x", eventID)
}
// decode header to get context data for each event
data[types.EventNameLabel] = evAbi.Name
data[types.BlockHeightLabel] = fmt.Sprintf("%v", header.GetHeight())
data[types.EventTypeLabel] = header.GetEventType().String()
data[types.TxTxHashLabel] = header.TxHash.String()
// build expected interface type array to get log event values
unpackedData := abi.GetPackingTypes(evAbi.Inputs)
// unpack event data (topics & data part)
if err := abi.UnpackEvent(&evAbi, log.Topics, log.Data, unpackedData...); err != nil {
return nil, errors.Wrap(err, "Could not unpack event data")
}
// for each decoded item value, stores it in given item name
for i, input := range evAbi.Inputs {
switch v := unpackedData[i].(type) {
case *crypto.Address:
data[input.Name] = v.String()
case *big.Int:
data[input.Name] = v.String()
case *string:
data[input.Name] = *v
default:
data[input.Name] = v
}
}
return data, nil
}