Drop another dependency

tools/cli/infrastructure.go

@@ -10,13 +10,13 @@ import (
 	"strings"
 	"unicode"
 
-	"github.com/mattn/go-isatty"
 	"github.com/mattn/go-runewidth"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"golang.org/x/sys/unix"
 
 	"kitty"
+	"kitty/tools/tty"
 	"kitty/tools/utils"
 )
 
@@ -488,7 +488,7 @@ func Init(root *cobra.Command) {
 	if kitty.VCSRevision != "" {
 		vs = vs + " (" + kitty.VCSRevision + ")"
 	}
-	stdout_is_terminal = isatty.IsTerminal(os.Stdout.Fd())
+	stdout_is_terminal = tty.IsTerminal(os.Stdout.Fd())
 	RootCmd = root
 	root.Version = vs
 	root.SetUsageFunc(func(cmd *cobra.Command) error { return show_usage(cmd, false) })

tools/cmd/at/main.go

@@ -9,7 +9,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/mattn/go-isatty"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 	"golang.org/x/sys/unix"
@@ -254,7 +253,7 @@ func get_password(password string, password_file string, password_env string, us
 	}
 	if ans == "" && password_file != "" {
 		if password_file == "-" {
-			if isatty.IsTerminal(os.Stdin.Fd()) {
+			if tty.IsTerminal(os.Stdin.Fd()) {
 				q, err := term.ReadPassword(int(os.Stdin.Fd()))
 				if err != nil {
 					ans = string(q)

tools/tty/tty.go

@@ -19,6 +19,12 @@ const (
 	TCSAFLUSH = 2
 )
 
+func IsTerminal(fd uintptr) bool {
+	var t unix.Termios
+	err := Tcgetattr(int(fd), &t)
+	return err == nil
+}
+
 type Term struct {
 	name   string
 	fd     int