// Copyright 2018 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. // This file contains a driver.UI implementation // that provides the readline functionality if possible. //go:build (darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || windows) && !appengine && !android package main import ( "fmt" "io" "os" "strings" "github.com/google/pprof/driver" "golang.org/x/term" ) func init() { newUI = newReadlineUI } // readlineUI implements driver.UI interface using the // golang.org/x/term package. // The upstream pprof command implements the same functionality // using the github.com/chzyer/readline package. type readlineUI struct { term *term.Terminal } func newReadlineUI() driver.UI { // disable readline UI in dumb terminal. (golang.org/issue/26254) if v := strings.ToLower(os.Getenv("TERM")); v == "" || v == "dumb" { return nil } // test if we can use term.ReadLine // that assumes operation in the raw mode. oldState, err := term.MakeRaw(0) if err != nil { return nil } term.Restore(0, oldState) rw := struct { io.Reader io.Writer }{os.Stdin, os.Stderr} return &readlineUI{term: term.NewTerminal(rw, "")} } // ReadLine returns a line of text (a command) read from the user. // prompt is printed before reading the command. func (r *readlineUI) ReadLine(prompt string) (string, error) { r.term.SetPrompt(prompt) // skip error checking because we tested it // when creating this readlineUI initially. oldState, _ := term.MakeRaw(0) defer term.Restore(0, oldState) s, err := r.term.ReadLine() return s, err } // Print shows a message to the user. // It formats the text as fmt.Print would and adds a final \n if not already present. // For line-based UI, Print writes to standard error. // (Standard output is reserved for report data.) func (r *readlineUI) Print(args ...any) { r.print(false, args...) } // PrintErr shows an error message to the user. // It formats the text as fmt.Print would and adds a final \n if not already present. // For line-based UI, PrintErr writes to standard error. func (r *readlineUI) PrintErr(args ...any) { r.print(true, args...) } func (r *readlineUI) print(withColor bool, args ...any) { text := fmt.Sprint(args...) if !strings.HasSuffix(text, "\n") { text += "\n" } if withColor { text = colorize(text) } fmt.Fprint(r.term, text) } // colorize prints the msg in red using ANSI color escapes. func colorize(msg string) string { const red = 31 var colorEscape = fmt.Sprintf("\033[0;%dm", red) var colorResetEscape = "\033[0m" return colorEscape + msg + colorResetEscape } // IsTerminal reports whether the UI is known to be tied to an // interactive terminal (as opposed to being redirected to a file). func (r *readlineUI) IsTerminal() bool { const stdout = 1 return term.IsTerminal(stdout) } // WantBrowser indicates whether browser should be opened with the -http option. func (r *readlineUI) WantBrowser() bool { return r.IsTerminal() } // SetAutoComplete instructs the UI to call complete(cmd) to obtain // the auto-completion of cmd, if the UI supports auto-completion at all. func (r *readlineUI) SetAutoComplete(complete func(string) string) { // TODO: Implement auto-completion support. }