path: root/generators/defaults.go

//go:generate go run defaults.go default.json defs.go

package main //build !none

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "os"
    "os/exec"
    "path"
    "strings"
)

func fatal(str string, v ...interface{}) {
    fmt.Fprintf(os.Stderr, str, v...)
    os.Exit(1)
}

type setting struct {
    Value   int64  `json:"v"`
    Comment string `json:"d"`
}

func main() {
    if len(os.Args) < 3 {
        fatal("usage %s <input> <output>\n", os.Args[0])
    }

    content, err := ioutil.ReadFile(os.Args[1])
    if err != nil {
        fatal("error reading file %v\n", err)
    }

    m := make(map[string]setting)
    json.Unmarshal(content, &m)

    filepath := path.Join(os.Getenv("GOPATH"), "src", "github.com", "ethereum", "go-ethereum", "core", os.Args[2])
    output, err := os.OpenFile(filepath, os.O_RDWR|os.O_CREATE, os.ModePerm /*0777*/)
    if err != nil {
        fatal("error opening file for writing %v\n", err)
    }

    output.WriteString(`package core

import "math/big"

var (
`)

    for name, setting := range m {
        output.WriteString(fmt.Sprintf("%s=big.NewInt(%d) // %s\n", strings.Title(name), setting.Value, setting.Comment))
    }

    output.WriteString(")\n")
    output.Close()

    cmd := exec.Command("gofmt", "-w", filepath)
    if err := cmd.Run(); err != nil {
        fatal("gofmt failed: %v\n", err)
    }
}