go-ethereum/cmd/utils/input.go

99 lines
2.7 KiB
Go

// Copyright 2016 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package utils
import (
"fmt"
"strings"
"github.com/peterh/liner"
)
// Holds the stdin line reader.
// Only this reader may be used for input because it keeps
// an internal buffer.
var Stdin = newUserInputReader()
type userInputReader struct {
*liner.State
warned bool
supported bool
normalMode liner.ModeApplier
rawMode liner.ModeApplier
}
func newUserInputReader() *userInputReader {
r := new(userInputReader)
// Get the original mode before calling NewLiner.
// This is usually regular "cooked" mode where characters echo.
normalMode, _ := liner.TerminalMode()
// Turn on liner. It switches to raw mode.
r.State = liner.NewLiner()
rawMode, err := liner.TerminalMode()
if err != nil || !liner.TerminalSupported() {
r.supported = false
} else {
r.supported = true
r.normalMode = normalMode
r.rawMode = rawMode
// Switch back to normal mode while we're not prompting.
normalMode.ApplyMode()
}
return r
}
func (r *userInputReader) Prompt(prompt string) (string, error) {
if r.supported {
r.rawMode.ApplyMode()
defer r.normalMode.ApplyMode()
} else {
// liner tries to be smart about printing the prompt
// and doesn't print anything if input is redirected.
// Un-smart it by printing the prompt always.
fmt.Print(prompt)
prompt = ""
defer fmt.Println()
}
return r.State.Prompt(prompt)
}
func (r *userInputReader) PasswordPrompt(prompt string) (passwd string, err error) {
if r.supported {
r.rawMode.ApplyMode()
defer r.normalMode.ApplyMode()
return r.State.PasswordPrompt(prompt)
}
if !r.warned {
fmt.Println("!! Unsupported terminal, password will be echoed.")
r.warned = true
}
// Just as in Prompt, handle printing the prompt here instead of relying on liner.
fmt.Print(prompt)
passwd, err = r.State.Prompt("")
fmt.Println()
return passwd, err
}
func (r *userInputReader) ConfirmPrompt(prompt string) (bool, error) {
prompt = prompt + " [y/N] "
input, err := r.Prompt(prompt)
if len(input) > 0 && strings.ToUpper(input[:1]) == "Y" {
return true, nil
}
return false, err
}