Open /dev/tty in non-blocking mode

Resolves gdamore#452.

nonblock_bsd.go

@@ -30,8 +30,7 @@ import (
 // that loop.  Normally we use VMIN 1 and VTIME 0, which ensures we pick up bytes when
 // they come but don't spin burning cycles.
 func (t *tScreen) nonBlocking(on bool) {
-	fd := int(os.Stdin.Fd())
-	tio, err := unix.IoctlGetTermios(fd, unix.TIOCGETA)
+	tio, err := unix.IoctlGetTermios(t.inFd, unix.TIOCGETA)
 	if err != nil {
 		return
 	}
@@ -44,7 +43,7 @@ func (t *tScreen) nonBlocking(on bool) {
 		tio.Cc[unix.VMIN] = 1
 	}
 
-	_ = syscall.SetNonblock(fd, on)
+	_ = syscall.SetNonblock(t.inFd, on)
 	// We want to set this *right now*.
-	_ = unix.IoctlSetTermios(fd, unix.TIOCSETA, tio)
+	_ = unix.IoctlSetTermios(t.inFd, unix.TIOCSETA, tio)
 }

nonblock_unix.go

@@ -17,7 +17,6 @@
 package tcell
 
 import (
-	"os"
 	"syscall"
 
 	"golang.org/x/sys/unix"
@@ -32,8 +31,7 @@ import (
 // that loop.  Normally we use VMIN 1 and VTIME 0, which ensures we pick up bytes when
 // they come but don't spin burning cycles.
 func (t *tScreen) nonBlocking(on bool) {
-	fd := int(os.Stdin.Fd())
-	tio, err := unix.IoctlGetTermios(fd, unix.TCGETS)
+	tio, err := unix.IoctlGetTermios(t.inFd, unix.TCGETS)
 	if err != nil {
 		return
 	}
@@ -46,7 +44,7 @@ func (t *tScreen) nonBlocking(on bool) {
 		tio.Cc[unix.VMIN] = 1
 	}
 
-	_ = syscall.SetNonblock(fd, on)
+	_ = syscall.SetNonblock(t.inFd, on)
 	// We want to set this *right now*.
-	_ = unix.IoctlSetTermios(fd, unix.TCSETS, tio)
+	_ = unix.IoctlSetTermios(t.inFd, unix.TCSETS, tio)
 }

tscreen.go

@@ -16,6 +16,7 @@ package tcell
 
 import (
 	"bytes"
+	"errors"
 	"io"
 	"os"
 	"strconv"
@@ -82,6 +83,7 @@ type tScreen struct {
 	fini         bool
 	cells        CellBuffer
 	in           *os.File
+	inFd         int
 	out          *os.File
 	buffering    bool // true if we are collecting writes to buf instead of sending directly to out
 	buf          bytes.Buffer
@@ -1484,20 +1486,29 @@ func (t *tScreen) mainLoop(stopQ chan struct{}) {
 }
 
 func (t *tScreen) inputLoop(stopQ chan struct{}) {
-
 	defer t.wg.Done()
+	var (
+		n   int
+		err error
+	)
 	for {
 		select {
 		case <-stopQ:
 			return
 		default:
 		}
+
+		err = t.in.SetReadDeadline(time.Now().Add(250 * time.Millisecond))
+		if err != nil {
+			panic(err)
+		}
+
 		chunk := make([]byte, 128)
-		n, e := t.in.Read(chunk)
-		switch e {
-		case nil:
-		default:
-			_ = t.PostEvent(NewEventError(e))
+		n, err = t.in.Read(chunk)
+		if errors.Is(err, os.ErrDeadlineExceeded) {
+			continue
+		} else if err != nil {
+			_ = t.PostEvent(NewEventError(err))
 			return
 		}
 		if n > 0 {
@@ -1575,7 +1586,6 @@ func (t *tScreen) HasKey(k Key) bool {
 
 func (t *tScreen) Resize(int, int, int, int) {}
 
-
 func (t *tScreen) Suspend() error {
 	t.disengage()
 	return nil

tscreen_unix.go

@@ -34,10 +34,10 @@ func (t *tScreen) engage() error {
 	if t.stopQ != nil {
 		return errors.New("already engaged")
 	}
-	if _, err := term.MakeRaw(int(t.in.Fd())); err != nil {
+	if _, err := term.MakeRaw(t.inFd); err != nil {
 		return err
 	}
-	if w, h, err := term.GetSize(int(t.in.Fd())); err == nil && w != 0 && h != 0 {
+	if w, h, err := term.GetSize(t.inFd); err == nil && w != 0 && h != 0 {
 		t.cells.Resize(w, h)
 	}
 	stopQ := make(chan struct{})
@@ -93,7 +93,7 @@ func (t *tScreen) disengage() {
 	t.enablePasting(false)
 
 	// restore the termios that we were started with
-	_ = term.Restore(int(t.in.Fd()), t.saved)
+	_ = term.Restore(t.inFd, t.saved)
 
 }
 
@@ -102,15 +102,19 @@ func (t *tScreen) disengage() {
 // so that it can be restored when the application terminates.
 func (t *tScreen) initialize() error {
 	var err error
-	t.out = os.Stdout
-	if t.in, err = os.Open("/dev/tty"); err != nil {
+	t.inFd, err = syscall.Open("/dev/tty", syscall.O_RDONLY|syscall.O_NONBLOCK, 0644)
+	if err != nil {
 		return err
 	}
+	t.in = os.NewFile(uintptr(t.inFd), "/dev/tty")
+
+	t.out = os.Stdout
 
-	t.saved, err = term.GetState(int(t.in.Fd()))
-	if err == nil {
-		return nil
+	t.saved, err = term.GetState(t.inFd)
+	if err != nil {
+		return err
 	}
+
 	return nil
 }
 
@@ -123,7 +127,7 @@ func (t *tScreen) finalize() {
 
 // getWinSize is called to obtain the terminal dimensions.
 func (t *tScreen) getWinSize() (int, int, error) {
-	return term.GetSize(int(t.in.Fd()))
+	return term.GetSize(t.inFd)
 }
 
 // Beep emits a beep to the terminal.