forked from toolshed/abra
117 lines
3.1 KiB
Go
117 lines
3.1 KiB
Go
// Package prompt provides utilities to prompt the user for input.
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package prompt
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import (
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"bufio"
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"context"
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"io"
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"os"
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"runtime"
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"strings"
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"github.com/docker/cli/cli/streams"
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"github.com/moby/term"
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)
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const ErrTerminated cancelledErr = "prompt terminated"
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type cancelledErr string
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func (e cancelledErr) Error() string {
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return string(e)
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}
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func (cancelledErr) Cancelled() {}
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// DisableInputEcho disables input echo on the provided streams.In.
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// This is useful when the user provides sensitive information like passwords.
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// The function returns a restore function that should be called to restore the
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// terminal state.
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//
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// TODO(thaJeztah): implement without depending on streams?
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func DisableInputEcho(ins *streams.In) (restore func() error, _ error) {
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oldState, err := term.SaveState(ins.FD())
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if err != nil {
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return nil, err
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}
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restore = func() error {
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return term.RestoreTerminal(ins.FD(), oldState)
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}
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return restore, term.DisableEcho(ins.FD(), oldState)
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}
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// ReadInput requests input from the user.
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//
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// It returns an empty string ("") with an [ErrTerminated] if the user terminates
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// the CLI with SIGINT or SIGTERM while the prompt is active. If the prompt
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// returns an error, the caller should close the [io.Reader] used for the prompt
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// and propagate the error up the stack to prevent the background goroutine
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// from blocking indefinitely.
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func ReadInput(ctx context.Context, in io.Reader, out io.Writer, message string) (string, error) {
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_, _ = out.Write([]byte(message))
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result := make(chan string)
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go func() {
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scanner := bufio.NewScanner(in)
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if scanner.Scan() {
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result <- strings.TrimSpace(scanner.Text())
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}
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}()
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select {
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case <-ctx.Done():
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_, _ = out.Write([]byte("\n"))
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return "", ErrTerminated
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case r := <-result:
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return r, nil
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}
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}
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// Confirm requests and checks confirmation from the user.
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//
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// It displays the provided message followed by "[y/N]". If the user
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// input 'y' or 'Y' it returns true otherwise false. If no message is provided,
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// "Are you sure you want to proceed? [y/N] " will be used instead.
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//
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// It returns false with an [ErrTerminated] if the user terminates
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// the CLI with SIGINT or SIGTERM while the prompt is active. If the prompt
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// returns an error, the caller should close the [io.Reader] used for the prompt
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// and propagate the error up the stack to prevent the background goroutine
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// from blocking indefinitely.
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func Confirm(ctx context.Context, in io.Reader, out io.Writer, message string) (bool, error) {
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if message == "" {
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message = "Are you sure you want to proceed?"
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}
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message += " [y/N] "
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_, _ = out.Write([]byte(message))
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// On Windows, force the use of the regular OS stdin stream.
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if runtime.GOOS == "windows" {
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in = streams.NewIn(os.Stdin)
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}
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result := make(chan bool)
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go func() {
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var res bool
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scanner := bufio.NewScanner(in)
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if scanner.Scan() {
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answer := strings.TrimSpace(scanner.Text())
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if strings.EqualFold(answer, "y") {
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res = true
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}
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}
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result <- res
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}()
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select {
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case <-ctx.Done():
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_, _ = out.Write([]byte("\n"))
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return false, ErrTerminated
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case r := <-result:
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return r, nil
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}
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}
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