Cancel key reading when 'execute' triggered via a server request (#4653)

Fix #4524
Close #4648

src/terminal.go

@@ -5615,7 +5615,7 @@ func (t *Terminal) Loop() error {
 			select {
 			case <-ctx.Done():
 				return
-			case t.keyChan <- t.tui.GetChar():
+			case t.keyChan <- t.tui.GetChar(t.listenAddr != nil):
 			}
 		}
 	}()
@@ -5702,6 +5702,13 @@ func (t *Terminal) Loop() error {
 					}
 				}
 			}
+			for _, action := range actions {
+				if action.t == actExecute {
+					t.tui.CancelGetChar()
+					break
+				}
+			}
+
 		case callback := <-t.callbackChan:
 			event = tui.Invalid.AsEvent()
 			actions = append(actions, &action{t: actAsync})

src/tui/dummy.go

@@ -34,11 +34,11 @@ func (r *FullscreenRenderer) ShowCursor()                        {}
 func (r *FullscreenRenderer) Refresh()                           {}
 func (r *FullscreenRenderer) Close()                             {}
 func (r *FullscreenRenderer) Size() TermSize                     { return TermSize{} }
-
-func (r *FullscreenRenderer) GetChar() Event { return Event{} }
-func (r *FullscreenRenderer) Top() int       { return 0 }
-func (r *FullscreenRenderer) MaxX() int      { return 0 }
-func (r *FullscreenRenderer) MaxY() int      { return 0 }
+func (r *FullscreenRenderer) Top() int                           { return 0 }
+func (r *FullscreenRenderer) MaxX() int                          { return 0 }
+func (r *FullscreenRenderer) MaxY() int                          { return 0 }
+func (r *FullscreenRenderer) GetChar(bool) Event                 { return Event{} }
+func (r *FullscreenRenderer) CancelGetChar()                     {}
 
 func (r *FullscreenRenderer) RefreshWindows(windows []Window) {}
 

src/tui/light.go

@@ -26,6 +26,7 @@ const (
 	escPollInterval = 5
 	offsetPollTries = 10
 	maxInputBuffer  = 1024 * 1024
+	maxSelectTries  = 100
 )
 
 const DefaultTtyDevice string = "/dev/tty"
@@ -49,6 +50,18 @@ const DIM string = "\x1b[2m"
 const CR string = DIM + "␍"
 const LF string = DIM + "␊"
 
+type getCharResult int
+
+const (
+	getCharSuccess getCharResult = iota
+	getCharError
+	getCharCancelled
+)
+
+func (r getCharResult) ok() bool {
+	return r == getCharSuccess
+}
+
 func (r *LightRenderer) stderrInternal(str string, allowNLCR bool, resetCode string) {
 	bytes := []byte(str)
 	runes := []rune{}
@@ -104,6 +117,7 @@ type LightRenderer struct {
 	clicks        [][2]int
 	ttyin         *os.File
 	ttyout        *os.File
+	cancel        func()
 	buffer        []byte
 	origState     *term.State
 	width         int
@@ -118,9 +132,9 @@ type LightRenderer struct {
 	x             int
 	maxHeightFunc func(int) int
 	showCursor    bool
+	mutex         sync.Mutex
 
 	// Windows only
-	mutex           sync.Mutex
 	ttyinChannel    chan byte
 	inHandle        uintptr
 	outHandle       uintptr
@@ -262,16 +276,18 @@ func getEnv(name string, defaultValue int) int {
 	return atoi(env, defaultValue)
 }
 
-func (r *LightRenderer) getBytes() ([]byte, error) {
-	bytes, err := r.getBytesInternal(r.buffer, false)
-	return bytes, err
+func (r *LightRenderer) getBytes(cancellable bool) ([]byte, getCharResult, error) {
+	return r.getBytesInternal(cancellable, r.buffer, false)
 }
 
-func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) ([]byte, error) {
-	c, ok := r.getch(nonblock)
-	if !nonblock && !ok {
+func (r *LightRenderer) getBytesInternal(cancellable bool, buffer []byte, nonblock bool) ([]byte, getCharResult, error) {
+	c, result := r.getch(cancellable, nonblock)
+	if result == getCharCancelled {
+		return buffer, getCharCancelled, nil
+	}
+	if !nonblock && !result.ok() {
 		r.Close()
-		return nil, errors.New("failed to read " + DefaultTtyDevice)
+		return nil, getCharError, errors.New("failed to read " + DefaultTtyDevice)
 	}
 
 	retries := 0
@@ -282,8 +298,8 @@ func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) ([]byte,
 
 	pc := c
 	for {
-		c, ok = r.getch(true)
-		if !ok {
+		c, result = r.getch(false, true)
+		if !result.ok() {
 			if retries > 0 {
 				retries--
 				time.Sleep(escPollInterval * time.Millisecond)
@@ -302,20 +318,24 @@ func (r *LightRenderer) getBytesInternal(buffer []byte, nonblock bool) ([]byte,
 		// so terminate fzf immediately.
 		if len(buffer) > maxInputBuffer {
 			r.Close()
-			return nil, fmt.Errorf("input buffer overflow (%d): %v", len(buffer), buffer)
+			return nil, getCharError, fmt.Errorf("input buffer overflow (%d): %v", len(buffer), buffer)
 		}
 	}
 
-	return buffer, nil
+	return buffer, getCharSuccess, nil
 }
 
-func (r *LightRenderer) GetChar() Event {
+func (r *LightRenderer) GetChar(cancellable bool) Event {
 	var err error
+	var result getCharResult
 	if len(r.buffer) == 0 {
-		r.buffer, err = r.getBytes()
+		r.buffer, result, err = r.getBytes(cancellable)
 		if err != nil {
 			return Event{Fatal, 0, nil}
 		}
+		if result == getCharCancelled {
+			return Event{Invalid, 0, nil}
+		}
 	}
 	if len(r.buffer) == 0 {
 		return Event{Fatal, 0, nil}
@@ -351,9 +371,14 @@ func (r *LightRenderer) GetChar() Event {
 		ev := r.escSequence(&sz)
 		// Second chance
 		if ev.Type == Invalid {
-			if r.buffer, err = r.getBytes(); err != nil {
+			r.buffer, result, err = r.getBytes(true)
+			if err != nil {
 				return Event{Fatal, 0, nil}
 			}
+			if result == getCharCancelled {
+				return Event{Invalid, 0, nil}
+			}
+
 			ev = r.escSequence(&sz)
 		}
 		return ev
@@ -371,6 +396,21 @@ func (r *LightRenderer) GetChar() Event {
 	return Event{Rune, char, nil}
 }
 
+func (r *LightRenderer) CancelGetChar() {
+	r.mutex.Lock()
+	if r.cancel != nil {
+		r.cancel()
+		r.cancel = nil
+	}
+	r.mutex.Unlock()
+}
+
+func (r *LightRenderer) setCancel(f func()) {
+	r.mutex.Lock()
+	r.cancel = f
+	r.mutex.Unlock()
+}
+
 func (r *LightRenderer) escSequence(sz *int) Event {
 	if len(r.buffer) < 2 {
 		return Event{Esc, 0, nil}

src/tui/light_test.go

@@ -15,10 +15,27 @@ func TestLightRenderer(t *testing.T) {
 
 	light_renderer := renderer.(*LightRenderer)
 
+	go func() {
+		for {
+			light_renderer.mutex.Lock()
+			ready := light_renderer.cancel != nil
+			light_renderer.mutex.Unlock()
+
+			if ready {
+				light_renderer.CancelGetChar()
+				break
+			}
+		}
+	}()
+	event := light_renderer.GetChar(true)
+	if event.Type != Invalid {
+		t.Error("Not cancelled")
+	}
+
 	assertCharSequence := func(sequence string, name string) {
 		bytes := []byte(sequence)
 		light_renderer.buffer = bytes
-		event := light_renderer.GetChar()
+		event := light_renderer.GetChar(true)
 		if event.KeyName() != name {
 			t.Errorf(
 				"sequence: %q | %v | '%s' (%s) != %s",

src/tui/light_unix.go

@@ -99,7 +99,7 @@ func (r *LightRenderer) findOffset() (row int, col int) {
 	var err error
 	bytes := []byte{}
 	for tries := range offsetPollTries {
-		bytes, err = r.getBytesInternal(bytes, tries > 0)
+		bytes, _, err = r.getBytesInternal(false, bytes, tries > 0)
 		if err != nil {
 			return -1, -1
 		}
@@ -114,15 +114,62 @@ func (r *LightRenderer) findOffset() (row int, col int) {
 	return -1, -1
 }
 
-func (r *LightRenderer) getch(nonblock bool) (int, bool) {
-	b := make([]byte, 1)
+func (r *LightRenderer) getch(cancellable bool, nonblock bool) (int, getCharResult) {
 	fd := r.fd()
-	util.SetNonblock(r.ttyin, nonblock)
-	_, err := util.Read(fd, b)
-	if err != nil {
-		return 0, false
+	getter := func() (int, getCharResult) {
+		b := make([]byte, 1)
+		util.SetNonblock(r.ttyin, nonblock)
+		_, err := util.Read(fd, b)
+		if err != nil {
+			return 0, getCharError
+		}
+		return int(b[0]), getCharSuccess
 	}
-	return int(b[0]), true
+	if nonblock || !cancellable {
+		return getter()
+	}
+
+	rpipe, wpipe, err := os.Pipe()
+	if err != nil {
+		// Fallback to blocking read without cancellation
+		return getter()
+	}
+	r.setCancel(func() {
+		wpipe.Write([]byte{0})
+	})
+	defer func() {
+		r.setCancel(nil)
+		rpipe.Close()
+		wpipe.Close()
+	}()
+
+	cancelFd := int(rpipe.Fd())
+	for range maxSelectTries {
+		var rfds unix.FdSet
+		limit := len(rfds.Bits) * unix.NFDBITS
+		if fd >= limit || cancelFd >= limit {
+			return getter()
+		}
+
+		rfds.Set(fd)
+		rfds.Set(cancelFd)
+		_, err := unix.Select(max(fd, cancelFd)+1, &rfds, nil, nil, nil)
+		if err != nil {
+			if err == syscall.EINTR {
+				continue
+			}
+			return 0, getCharError
+		}
+
+		if rfds.IsSet(cancelFd) {
+			return 0, getCharCancelled
+		}
+
+		if rfds.IsSet(fd) {
+			return getter()
+		}
+	}
+	return 0, getCharError
 }
 
 func (r *LightRenderer) Size() TermSize {

src/tui/light_windows.go

@@ -151,16 +151,33 @@ func (r *LightRenderer) findOffset() (row int, col int) {
 	return int(bufferInfo.CursorPosition.Y), int(bufferInfo.CursorPosition.X)
 }
 
-func (r *LightRenderer) getch(nonblock bool) (int, bool) {
-	if nonblock {
-		select {
-		case bc := <-r.ttyinChannel:
-			return int(bc), true
-		case <-time.After(timeoutInterval * time.Millisecond):
-			return 0, false
-		}
-	} else {
+func (r *LightRenderer) getch(cancellable bool, nonblock bool) (int, getCharResult) {
+	if !nonblock && !cancellable {
 		bc := <-r.ttyinChannel
-		return int(bc), true
+		return int(bc), getCharSuccess
+	}
+
+	var timeout <-chan time.Time
+	if nonblock {
+		timeout = time.After(timeoutInterval * time.Millisecond)
+	}
+
+	var cancel chan struct{}
+	if cancellable {
+		cancel = make(chan struct{})
+		r.setCancel(func() {
+			close(cancel)
+		})
+		defer r.setCancel(nil)
+	}
+
+	select {
+	case bc := <-r.ttyinChannel:
+		return int(bc), getCharSuccess
+	case <-cancel:
+		return 0, getCharCancelled
+	case <-timeout:
+		// NOTE: not really an error
+		return 0, getCharError
 	}
 }

src/tui/tcell.go

@@ -246,7 +246,7 @@ func (r *FullscreenRenderer) Size() TermSize {
 	return TermSize{lines, cols, 0, 0}
 }
 
-func (r *FullscreenRenderer) GetChar() Event {
+func (r *FullscreenRenderer) GetChar(cancellable bool) Event {
 	ev := _screen.PollEvent()
 	switch ev := ev.(type) {
 	case *tcell.EventPaste:
@@ -703,6 +703,10 @@ func (r *FullscreenRenderer) GetChar() Event {
 	return Event{Invalid, 0, nil}
 }
 
+func (r *FullscreenRenderer) CancelGetChar() {
+	// TODO
+}
+
 func (r *FullscreenRenderer) Pause(clear bool) {
 	if clear {
 		_screen.Suspend()

src/tui/tui.go

@@ -749,7 +749,8 @@ type Renderer interface {
 	HideCursor()
 	ShowCursor()
 
-	GetChar() Event
+	GetChar(cancellable bool) Event
+	CancelGetChar()
 
 	Top() int
 	MaxX() int