koki-develop/qiita-cli

package util

import (
    "fmt"
    "os"
    "path"
    "path/filepath"
)

func CreateFile(filename string) (*os.File, error) {
    out := filename
    dir := filepath.Dir(filename)
    ext := filepath.Ext(filename)
    base := filepath.Base(filename)
    base = base[:len(base)-len(ext)]

    for i := 0; ; i++ {
        ex, err := Exists(out)
        if err != nil {
            return nil, err
        }
        if !ex {
            break
        }

        out = path.Join(dir, fmt.Sprintf("%s(%d)%s", base, i, ext))
    }

    f, err := os.Create(out)
    if err != nil {
        return nil, err
    }
    return f, nil
}

func Exists(p string) (bool, error) {
    if _, err := os.Stat(p); err != nil {
        if os.IsNotExist(err) {
            return false, nil
        }
        return false, err
    }

    return true, nil
}