path: root/cmd/evm/json_logger.go

// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package main

import (
    "encoding/json"
    "io"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/common/math"
    "github.com/ethereum/go-ethereum/core/vm"
)

type JSONLogger struct {
    encoder *json.Encoder
    cfg     *vm.LogConfig
}

func NewJSONLogger(cfg *vm.LogConfig, writer io.Writer) *JSONLogger {
    return &JSONLogger{json.NewEncoder(writer), cfg}
}

// CaptureState outputs state information on the logger.
func (l *JSONLogger) CaptureState(env *vm.EVM, pc uint64, op vm.OpCode, gas, cost uint64, memory *vm.Memory, stack *vm.Stack, contract *vm.Contract, depth int, err error) error {
    log := vm.StructLog{
        Pc:         pc,
        Op:         op,
        Gas:        gas,
        GasCost:    cost,
        MemorySize: memory.Len(),
        Storage:    nil,
        Depth:      depth,
        Err:        err,
    }
    if !l.cfg.DisableMemory {
        log.Memory = memory.Data()
    }
    if !l.cfg.DisableStack {
        log.Stack = stack.Data()
    }
    return l.encoder.Encode(log)
}

// CaptureEnd is triggered at end of execution.
func (l *JSONLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) error {
    type endLog struct {
        Output  string              `json:"output"`
        GasUsed math.HexOrDecimal64 `json:"gasUsed"`
        Time    time.Duration       `json:"time"`
        Err     string              `json:"error,omitempty"`
    }
    if err != nil {
        return l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, err.Error()})
    }
    return l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, ""})
}