This change introduces 2 new optional methods; `enter()` and `exit()` for js tracers, and makes `step()` optiona. The two new methods are invoked when entering and exiting a call frame (but not invoked for the outermost scope, which has it's own methods). Currently these are the data fields passed to each of them:
    enter: type (opcode), from, to, input, gas, value
    exit: output, gasUsed, error
The PR also comes with a re-write of the callTracer. As a backup we keep the previous tracing script under the name `callTracerLegacy`. Behaviour of both tracers are equivalent for the most part, although there are some small differences (improvements), where the new tracer is more correct / has more information.
		
	
		
			
				
	
	
		
			95 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			95 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2017 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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	"encoding/json"
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	"io"
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	"math/big"
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	"time"
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	"github.com/ethereum/go-ethereum/common"
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	"github.com/ethereum/go-ethereum/common/math"
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)
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type JSONLogger struct {
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	encoder *json.Encoder
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	cfg     *LogConfig
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}
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// NewJSONLogger creates a new EVM tracer that prints execution steps as JSON objects
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// into the provided stream.
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func NewJSONLogger(cfg *LogConfig, writer io.Writer) *JSONLogger {
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	l := &JSONLogger{json.NewEncoder(writer), cfg}
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	if l.cfg == nil {
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		l.cfg = &LogConfig{}
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	}
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	return l
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}
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func (l *JSONLogger) CaptureStart(env *EVM, from, to common.Address, create bool, input []byte, gas uint64, value *big.Int) {
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}
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func (l *JSONLogger) CaptureFault(*EVM, uint64, OpCode, uint64, uint64, *ScopeContext, int, error) {}
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// CaptureState outputs state information on the logger.
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func (l *JSONLogger) CaptureState(env *EVM, pc uint64, op OpCode, gas, cost uint64, scope *ScopeContext, rData []byte, depth int, err error) {
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	memory := scope.Memory
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	stack := scope.Stack
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	log := StructLog{
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		Pc:            pc,
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		Op:            op,
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		Gas:           gas,
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		GasCost:       cost,
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		MemorySize:    memory.Len(),
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		Depth:         depth,
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		RefundCounter: env.StateDB.GetRefund(),
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		Err:           err,
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	}
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	if l.cfg.EnableMemory {
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		log.Memory = memory.Data()
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	}
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	if !l.cfg.DisableStack {
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		log.Stack = stack.data
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	}
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	if l.cfg.EnableReturnData {
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		log.ReturnData = rData
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	}
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	l.encoder.Encode(log)
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}
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// CaptureEnd is triggered at end of execution.
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func (l *JSONLogger) CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error) {
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	type endLog struct {
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		Output  string              `json:"output"`
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		GasUsed math.HexOrDecimal64 `json:"gasUsed"`
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		Time    time.Duration       `json:"time"`
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		Err     string              `json:"error,omitempty"`
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	}
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	var errMsg string
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	if err != nil {
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		errMsg = err.Error()
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	}
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	l.encoder.Encode(endLog{common.Bytes2Hex(output), math.HexOrDecimal64(gasUsed), t, errMsg})
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}
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func (l *JSONLogger) CaptureEnter(typ OpCode, from common.Address, to common.Address, input []byte, gas uint64, value *big.Int) {
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}
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func (l *JSONLogger) CaptureExit(output []byte, gasUsed uint64, err error) {}
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