Use/demo history from PR for golang/go#68780

Author: ldemailly

example/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"errors"
+	"flag"
 	"fmt"
 	"io"
 	"os"
@@ -56,7 +57,7 @@ func autoCompleteCallback(line string, pos int, key rune) (newLine string, newPo
 
 func Main() int {
 	// Pending https://github.com/golang/go/issues/68780
-	// flagHistory := flag.String("history", "", "History `file` to use")
+	flagHistory := flag.String("history", "/tmp/terminal_history", "History `file` to use")
 	cli.Main()
 	t, err := terminal.Open()
 	if err != nil {
@@ -65,6 +66,7 @@ func Main() int {
 	defer t.Close()
 	t.SetPrompt("Terminal demo> ")
 	t.LoggerSetup()
+	t.SetHistoryFile(*flagHistory)
 	fmt.Fprintf(t.Out, "Terminal is open\nis valid %t\nuse exit or ^D or ^C to exit\n", t.IsTerminal())
 	fmt.Fprintf(t.Out, "Use 'prompt <new prompt>' to change the prompt\n")
 	fmt.Fprintf(t.Out, "Try 'after duration text...' to see text showing in the middle of edits after said duration\n")

go.mod

@@ -9,6 +9,7 @@ require (
 )
 
 // replace fortio.org/cli => ../cli
+replace golang.org/x/term => github.com/ldemailly/term v0.0.0-20240808164309-1ca6c26d14bf
 
 require (
 	fortio.org/struct2env v0.4.1 // indirect

go.sum

@@ -8,9 +8,9 @@ fortio.org/version v1.0.4 h1:FWUMpJ+hVTNc4RhvvOJzb0xesrlRmG/a+D6bjbQ4+5U=
 fortio.org/version v1.0.4/go.mod h1:2JQp9Ax+tm6QKiGuzR5nJY63kFeANcgrZ0osoQFDVm0=
 github.com/kortschak/goroutine v1.1.2 h1:lhllcCuERxMIK5cYr8yohZZScL1na+JM5JYPRclWjck=
 github.com/kortschak/goroutine v1.1.2/go.mod h1:zKpXs1FWN/6mXasDQzfl7g0LrGFIOiA6cLs9eXKyaMY=
+github.com/ldemailly/term v0.0.0-20240808164309-1ca6c26d14bf h1:tSC3QHTyGX/bno3fLgNBikbqJ5+/qBh8bFJVnCXsBrw=
+github.com/ldemailly/term v0.0.0-20240808164309-1ca6c26d14bf/go.mod h1:DgV24QBUrK6jhZXl+20l6UWznPlwAHm1Q1mGHtydmSk=
 golang.org/x/crypto/x509roots/fallback v0.0.0-20240626151235-a6a393ffd658 h1:i7K6wQLN/0oxF7FT3tKkfMCstxoT4VGG36YIB9ZKLzI=
 golang.org/x/crypto/x509roots/fallback v0.0.0-20240626151235-a6a393ffd658/go.mod h1:kNa9WdvYnzFwC79zRpLRMJbdEFlhyM5RPFBBZp/wWH8=
 golang.org/x/sys v0.23.0 h1:YfKFowiIMvtgl1UERQoTPPToxltDeZfbj4H7dVUCwmM=
 golang.org/x/sys v0.23.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/term v0.23.0 h1:F6D4vR+EHoL9/sWAWgAR1H2DcHr4PareCbAaCo1RpuU=
-golang.org/x/term v0.23.0/go.mod h1:DgV24QBUrK6jhZXl+20l6UWznPlwAHm1Q1mGHtydmSk=

terminal.go

@@ -2,6 +2,7 @@
 package terminal // import "fortio.org/terminal"
 
 import (
+	"bufio"
 	"io"
 	"os"
 
@@ -10,10 +11,11 @@ import (
 )
 
 type Terminal struct {
-	fd       int
-	oldState *term.State
-	term     *term.Terminal
-	Out      io.Writer
+	fd          int
+	oldState    *term.State
+	term        *term.Terminal
+	Out         io.Writer
+	historyFile string
 }
 
 // CRWriter is a writer that adds \r before each \n.
@@ -100,13 +102,75 @@ func (t *Terminal) LoggerSetup() {
 	log.SetColorMode()
 }
 
+func (t *Terminal) SetHistoryFile(f string) {
+	t.historyFile = f
+	entries := readOrCreateHistory(f)
+	for _, e := range entries {
+		t.term.AddToHistory(e)
+	}
+	log.Infof("Loaded %d history entries from %s", len(entries), f)
+}
+
+func readOrCreateHistory(f string) []string {
+	if f == "" {
+		log.Infof("No history file specified")
+		return nil
+	}
+	// open file or create it
+	h, err := os.OpenFile(f, os.O_RDWR|os.O_CREATE, 0o600)
+	if err != nil {
+		log.Errf("Error opening history file %s: %v", f, err)
+		return nil
+	}
+	defer h.Close()
+	// read lines separated by \n
+	var lines []string
+	scanner := bufio.NewScanner(h)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+	if err := scanner.Err(); err != nil {
+		log.Errf("Error reading history file %s: %v", f, err)
+		return nil
+	}
+	return lines
+}
+
+func saveHistory(f string, h []string) {
+	if f == "" {
+		log.Infof("No history file specified")
+		return
+	}
+	// open file or create it
+	hf, err := os.OpenFile(f, os.O_RDWR|os.O_CREATE, 0o600)
+	if err != nil {
+		log.Errf("Error opening history file %s: %v", f, err)
+		return
+	}
+	defer hf.Close()
+	// write lines separated by \n
+	for _, l := range h {
+		_, err := hf.WriteString(l + "\n")
+		if err != nil {
+			log.Errf("Error writing history file %s: %v", f, err)
+			return
+		}
+	}
+}
+
 func (t *Terminal) Close() error {
 	if t.oldState == nil {
 		return nil
 	}
 	err := term.Restore(t.fd, t.oldState)
 	t.oldState = nil
 	t.Out = os.Stderr
+	// saving history if any
+	if t.historyFile != "" {
+		h := t.term.History()
+		log.Infof("Saving history (%d commands) to %s", len(h), t.historyFile)
+		saveHistory(t.historyFile, h)
+	}
 	return err
 }