go-ethereum/eth/tracers/tracers.go

85 lines
2.9 KiB
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 tracers is a collection of JavaScript transaction tracers.
package tracers
import (
"encoding/json"
"strings"
"unicode"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/eth/tracers/internal/tracers"
)
// Tracer interface extends vm.EVMLogger and additionally
// allows collecting the tracing result.
type Tracer interface {
vm.EVMLogger
GetResult() (json.RawMessage, error)
// Stop terminates execution of the tracer at the first opportune moment.
Stop(err error)
}
var (
nativeTracers map[string]func() Tracer = make(map[string]func() Tracer)
jsTracers = make(map[string]string)
)
// RegisterNativeTracer makes native tracers which adhere
// to the `Tracer` interface available to the rest of the codebase.
// It is typically invoked in the `init()` function, e.g. see the `native/call.go`.
func RegisterNativeTracer(name string, ctor func() Tracer) {
nativeTracers[name] = ctor
}
// New returns a new instance of a tracer,
// 1. If 'code' is the name of a registered native tracer, then that tracer
// is instantiated and returned
// 2. If 'code' is the name of a registered js-tracer, then that tracer is
// instantiated and returned
// 3. Otherwise, the code is interpreted as the js code of a js-tracer, and
// is evaluated and returned.
func New(code string, ctx *Context) (Tracer, error) {
// Resolve native tracer
if fn, ok := nativeTracers[code]; ok {
return fn(), nil
}
// Resolve js-tracers by name and assemble the tracer object
if tracer, ok := jsTracers[code]; ok {
code = tracer
}
return newJsTracer(code, ctx)
}
// camel converts a snake cased input string into a camel cased output.
func camel(str string) string {
pieces := strings.Split(str, "_")
for i := 1; i < len(pieces); i++ {
pieces[i] = string(unicode.ToUpper(rune(pieces[i][0]))) + pieces[i][1:]
}
return strings.Join(pieces, "")
}
// init retrieves the JavaScript transaction tracers included in go-ethereum.
func init() {
for _, file := range tracers.AssetNames() {
name := camel(strings.TrimSuffix(file, ".js"))
jsTracers[name] = string(tracers.MustAsset(file))
}
}