From ffaf58f0a98bd987bbe76e8669bb22c405dcd62a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= Date: Fri, 6 May 2016 12:40:23 +0300 Subject: cmd, console: split off the console into a reusable package --- console/prompter.go | 156 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 156 insertions(+) create mode 100644 console/prompter.go (limited to 'console/prompter.go') diff --git a/console/prompter.go b/console/prompter.go new file mode 100644 index 000000000..5039e8b1c --- /dev/null +++ b/console/prompter.go @@ -0,0 +1,156 @@ +// Copyright 2016 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 . + +package console + +import ( + "fmt" + "strings" + + "github.com/peterh/liner" +) + +// TerminalPrompter holds the stdin line reader (also using stdout for printing +// prompts). Only this reader may be used for input because it keeps an internal +// buffer. +var TerminalPrompter = newTerminalPrompter() + +// UserPrompter defines the methods needed by the console to promt the user for +// various types of inputs. +type UserPrompter interface { + // PromptInput displays the given prompt to the user and requests some textual + // data to be entered, returning the input of the user. + PromptInput(prompt string) (string, error) + + // PromptPassword displays the given prompt to the user and requests some textual + // data to be entered, but one which must not be echoed out into the terminal. + // The method returns the input provided by the user. + PromptPassword(prompt string) (string, error) + + // PromptConfirm displays the given prompt to the user and requests a boolean + // choice to be made, returning that choice. + PromptConfirm(prompt string) (bool, error) + + // SetScrollHistory sets the the input scrollback history that the prompter will + // allow the user to scoll back to. + SetScrollHistory(history []string) + + // SetWordCompleter sets the completion function that the prompter will call to + // fetch completion candidates when the user presses tab. + SetWordCompleter(completer WordCompleter) +} + +// WordCompleter takes the currently edited line with the cursor position and +// returns the completion candidates for the partial word to be completed. If +// the line is "Hello, wo!!!" and the cursor is before the first '!', ("Hello, +// wo!!!", 9) is passed to the completer which may returns ("Hello, ", {"world", +// "Word"}, "!!!") to have "Hello, world!!!". +type WordCompleter func(line string, pos int) (string, []string, string) + +// terminalPrompter is a UserPrompter backed by the liner package. It supports +// prompting the user for various input, among others for non-echoing password +// input. +type terminalPrompter struct { + *liner.State + warned bool + supported bool + normalMode liner.ModeApplier + rawMode liner.ModeApplier +} + +// newTerminalPrompter creates a liner based user input prompter working off the +// standard input and output streams. +func newTerminalPrompter() *terminalPrompter { + r := new(terminalPrompter) + // 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() + } + r.SetCtrlCAborts(true) + r.SetTabCompletionStyle(liner.TabPrints) + + return r +} + +// PromptInput displays the given prompt to the user and requests some textual +// data to be entered, returning the input of the user. +func (r *terminalPrompter) PromptInput(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) +} + +// PromptPassword displays the given prompt to the user and requests some textual +// data to be entered, but one which must not be echoed out into the terminal. +// The method returns the input provided by the user. +func (r *terminalPrompter) PromptPassword(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 +} + +// PromptConfirm displays the given prompt to the user and requests a boolean +// choice to be made, returning that choice. +func (r *terminalPrompter) PromptConfirm(prompt string) (bool, error) { + input, err := r.Prompt(prompt + " [y/N] ") + if len(input) > 0 && strings.ToUpper(input[:1]) == "Y" { + return true, nil + } + return false, err +} + +// SetScrollHistory sets the the input scrollback history that the prompter will +// allow the user to scoll back to. +func (r *terminalPrompter) SetScrollHistory(history []string) { + r.State.ReadHistory(strings.NewReader(strings.Join(history, "\n"))) +} + +// SetWordCompleter sets the completion function that the prompter will call to +// fetch completion candidates when the user presses tab. +func (r *terminalPrompter) SetWordCompleter(completer WordCompleter) { + r.State.SetWordCompleter(liner.WordCompleter(completer)) +} -- cgit v1.2.3