// Copyright (c) 2015-2021 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program 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 Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. package config import (	"errors"	"fmt"	"net"	"syscall" 	"github.com/minio/minio/internal/color") // Err is a structure which contains all information// to print a fatal error message in json or pretty mode// Err implements error so we can use it anywheretype Err struct {	msg    string	detail string	action string	hint   string} // Clone returns a new Err struct with the same informationfunc (u Err) Clone() Err {	return Err{		msg:    u.msg,		detail: u.detail,		action: u.action,		hint:   u.hint,	}} // Error returns the error messagefunc (u Err) Error() string {	if u.detail == "" {		if u.msg != "" {			return u.msg		}		return "<nil>"	}	return u.detail} // Msg - Replace the current error's messagefunc (u Err) Msg(m string, args ...interface{}) Err {	e := u.Clone()	e.msg = fmt.Sprintf(m, args...)	return e} // Hint - Replace the current error's messagefunc (u Err) Hint(m string, args ...interface{}) Err {	e := u.Clone()	e.hint = fmt.Sprintf(m, args...)	return e} // ErrFn function wrappertype ErrFn func(err error) Err // Create a UI error generator, this is needed to simplify// the update of the detailed error message in several places// in MinIO codefunc newErrFn(msg, action, hint string) ErrFn {	return func(err error) Err {		u := Err{			msg:    msg,			action: action,			hint:   hint,		}		if err != nil {			u.detail = err.Error()		}		return u	}} // ErrorToErr inspects the passed error and transforms it// to the appropriate UI error.func ErrorToErr(err error) Err {	if err == nil {		return Err{}	} 	// If this is already a Err, do nothing	if e, ok := err.(Err); ok {		return e	} 	// Show a generic message for known golang errors	if errors.Is(err, syscall.EADDRINUSE) {		return ErrPortAlreadyInUse(err).Msg("Specified port is already in use")	} else if errors.Is(err, syscall.EACCES) || errors.Is(err, syscall.EPERM) {		switch err.(type) {		case *net.OpError:			return ErrPortAccess(err).Msg("Insufficient permissions to use specified port")		}	} 	// Failed to identify what type of error this, return a simple UI error	return Err{msg: err.Error()}} // FmtError converts a fatal error message to a more clear error// using some colorsfunc FmtError(introMsg string, err error, jsonFlag bool) string {	renderedTxt := ""	uiErr := ErrorToErr(err)	// JSON print	if jsonFlag {		// Message text in json should be simple		if uiErr.detail != "" {			return uiErr.msg + ": " + uiErr.detail		}		return uiErr.msg	}	// Pretty print error message	introMsg += ": "	if uiErr.msg != "" {		introMsg += color.Bold(uiErr.msg)	} else {		introMsg += color.Bold(err.Error())	}	renderedTxt += color.Red(introMsg) + "\n"	// Add action message	if uiErr.action != "" {		renderedTxt += "> " + color.BgYellow(color.Black(uiErr.action)) + "\n"	}	// Add hint	if uiErr.hint != "" {		renderedTxt += color.Bold("HINT:") + "\n"		renderedTxt += "  " + uiErr.hint	}	return renderedTxt}