Refactor

backend/localcommand/local_command.go

@@ -0,0 +1,136 @@
+package localcommand
+
+import (
+	"os"
+	"os/exec"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"github.com/kr/pty"
+	"github.com/pkg/errors"
+)
+
+const (
+	DefaultCloseSignal  = syscall.SIGINT
+	DefaultCloseTimeout = 10 * time.Second
+)
+
+type LocalCommand struct {
+	command string
+	argv    []string
+
+	closeSignal  syscall.Signal
+	closeTimeout time.Duration
+
+	cmd       *exec.Cmd
+	pty       *os.File
+	ptyClosed chan struct{}
+}
+
+func New(command string, argv []string, options ...Option) (*LocalCommand, error) {
+	cmd := exec.Command(command, argv...)
+
+	pty, err := pty.Start(cmd)
+	if err != nil {
+		// todo close cmd?
+		return nil, errors.Wrapf(err, "failed to start command `%s`", command)
+	}
+	ptyClosed := make(chan struct{})
+
+	lcmd := &LocalCommand{
+		command: command,
+		argv:    argv,
+
+		closeSignal:  DefaultCloseSignal,
+		closeTimeout: DefaultCloseTimeout,
+
+		cmd:       cmd,
+		pty:       pty,
+		ptyClosed: ptyClosed,
+	}
+
+	for _, option := range options {
+		option(lcmd)
+	}
+
+	// When the process is closed by the user,
+	// close pty so that Read() on the pty breaks with an EOF.
+	go func() {
+		defer func() {
+			lcmd.pty.Close()
+			close(lcmd.ptyClosed)
+		}()
+
+		lcmd.cmd.Wait()
+	}()
+
+	return lcmd, nil
+}
+
+func (lcmd *LocalCommand) Read(p []byte) (n int, err error) {
+	return lcmd.pty.Read(p)
+}
+
+func (lcmd *LocalCommand) Write(p []byte) (n int, err error) {
+	return lcmd.pty.Write(p)
+}
+
+func (lcmd *LocalCommand) Close() error {
+	if lcmd.cmd != nil && lcmd.cmd.Process != nil {
+		lcmd.cmd.Process.Signal(lcmd.closeSignal)
+	}
+	for {
+		select {
+		case <-lcmd.ptyClosed:
+			return nil
+		case <-lcmd.closeTimeoutC():
+			lcmd.cmd.Process.Signal(syscall.SIGKILL)
+		}
+	}
+}
+
+func (lcmd *LocalCommand) WindowTitleVariables() map[string]interface{} {
+	return map[string]interface{}{
+		"command": lcmd.command,
+		"argv":    lcmd.argv,
+		"pid":     lcmd.cmd.Process.Pid,
+	}
+}
+
+func (lcmd *LocalCommand) ResizeTerminal(width int, height int) error {
+	window := struct {
+		row uint16
+		col uint16
+		x   uint16
+		y   uint16
+	}{
+		uint16(height),
+		uint16(width),
+		0,
+		0,
+	}
+	_, _, errno := syscall.Syscall(
+		syscall.SYS_IOCTL,
+		lcmd.pty.Fd(),
+		syscall.TIOCSWINSZ,
+		uintptr(unsafe.Pointer(&window)),
+	)
+	if errno != 0 {
+		return errno
+	} else {
+		return nil
+	}
+}
+
+func (lcmd *LocalCommand) GetTerminalSize() (int, int, error) {
+	return pty.Getsize(lcmd.pty)
+}
+
+func (lcmd *LocalCommand) closeTimeoutC() <-chan time.Time {
+	if lcmd.closeTimeout >= 0 {
+		return time.After(lcmd.closeTimeout)
+	}
+
+	return make(chan time.Time)
+}