fixes #561 Add clipboard support.

_demos/clipboard.go

@@ -0,0 +1,115 @@
+//go:build ignore
+// +build ignore
+
+// Copyright 2024 The TCell Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use file except in compliance with the License.
+// You may obtain a copy of the license at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"unicode/utf8"
+
+	"github.com/gdamore/tcell/v2"
+	"github.com/gdamore/tcell/v2/encoding"
+
+	"github.com/mattn/go-runewidth"
+)
+
+func emitStr(s tcell.Screen, x, y int, style tcell.Style, str string) {
+	for _, c := range str {
+		var comb []rune
+		w := runewidth.RuneWidth(c)
+		if w == 0 {
+			comb = []rune{c}
+			c = ' '
+			w = 1
+		}
+		s.SetContent(x, y, c, comb, style)
+		x += w
+	}
+}
+
+var clipboard []byte
+
+func displayHelloWorld(s tcell.Screen) {
+	w, h := s.Size()
+	s.Clear()
+	style := tcell.StyleDefault.Foreground(tcell.ColorCadetBlue.TrueColor()).Background(tcell.ColorWhite)
+	emitStr(s, w/2-14, h/2, style, "Press 1 to set clipboard")
+	emitStr(s, w/2-14, h/2+1, style, "Press 2 to get clipboard")
+
+	msg := ""
+	if utf8.Valid(clipboard) {
+		cp := string(clipboard)
+		if len(cp) >= w-25 {
+			cp = cp[:21] + " ..."
+		}
+		msg = fmt.Sprintf("Clipboard (%d bytes): %s", len(clipboard), cp)
+	} else if clipboard != nil {
+		msg = fmt.Sprintf("Clipboard (%d bytes) Not Valid UTF-8", len(clipboard))
+	} else {
+		msg = "No clipboard data"
+	}
+	emitStr(s, (w-len(msg))/2, h/2+3, tcell.StyleDefault, msg)
+	emitStr(s, w/2-9, h/2+5, tcell.StyleDefault, "Press ESC to exit.")
+	s.Show()
+}
+
+// This program just prints "Hello, World!".  Press ESC to exit.
+func main() {
+	encoding.Register()
+
+	s, e := tcell.NewScreen()
+	if e != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", e)
+		os.Exit(1)
+	}
+	if e := s.Init(); e != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", e)
+		os.Exit(1)
+	}
+
+	defStyle := tcell.StyleDefault.
+		Background(tcell.ColorBlack).
+		Foreground(tcell.ColorWhite)
+	s.SetStyle(defStyle)
+
+	displayHelloWorld(s)
+
+	for {
+		switch ev := s.PollEvent().(type) {
+		case *tcell.EventResize:
+			s.Sync()
+			displayHelloWorld(s)
+		case *tcell.EventKey:
+			switch ev.Key() {
+			case tcell.KeyRune:
+				switch ev.Rune() {
+				case '1':
+					s.SetClipboard([]byte("Enjoy your new clipboard content!"))
+				case '2':
+					s.GetClipboard()
+				}
+			case tcell.KeyEscape:
+				s.Fini()
+				os.Exit(0)
+			}
+		case *tcell.EventClipboard:
+			clipboard = ev.Data()
+			displayHelloWorld(s)
+		}
+	}
+}

console_win.go

@@ -1312,6 +1312,12 @@ func (s *cScreen) HasMouse() bool {
 	return true
 }
 
+func (s *cScreen) SetClipboard(_ []byte) {
+}
+
+func (s *cScreen) GetClipboard() {
+}
+
 func (s *cScreen) Resize(int, int, int, int) {}
 
 func (s *cScreen) HasKey(k Key) bool {

paste.go

@@ -1,4 +1,4 @@
-// Copyright 2020 The TCell Authors
+// Copyright 2024 The TCell Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use file except in compliance with the License.
@@ -19,12 +19,14 @@ import (
 )
 
 // EventPaste is used to mark the start and end of a bracketed paste.
-// An event with .Start() true will be sent to mark the start.
-// Then a number of keys will be sent to indicate that the content
-// is pasted in.  At the end, an event with .Start() false will be sent.
+//
+// An event with .Start() true will be sent to mark the start of a bracketed paste,
+// followed by a number of keys (string data) for the content, ending with the
+// an event with .End() true.
 type EventPaste struct {
 	start bool
 	t     time.Time
+	data  []byte
 }
 
 // When returns the time when this EventPaste was created.
@@ -46,3 +48,25 @@ func (ev *EventPaste) End() bool {
 func NewEventPaste(start bool) *EventPaste {
 	return &EventPaste{t: time.Now(), start: start}
 }
+
+// NewEventClipboard returns a new NewEventClipboard with a data payload
+func NewEventClipboard(data []byte) *EventClipboard {
+	return &EventClipboard{t: time.Now(), data: data}
+}
+
+// EventClipboard represents data from the clipboard,
+// in response to a GetClipboard request.
+type EventClipboard struct {
+	t    time.Time
+	data []byte
+}
+
+// Data returns the attached binary data.
+func (ev *EventClipboard) Data() []byte {
+	return ev.data
+}
+
+// When returns the time when this event was created.
+func (ev *EventClipboard) When() time.Time {
+	return ev.t
+}

screen.go

@@ -272,6 +272,17 @@ type Screen interface {
 	// Tcell may attempt to save and restore the window title on entry and exit, but
 	// the results may vary.  Use of unicode characters may not be supported.
 	SetTitle(string)
+
+	// SetClipboard is used to post arbitrary data to the system clipboard.
+	// This need not be UTF-8 string data.  It's up to the recipient to decode the
+	// data meaningfully.  Terminals may prevent this for security reasons.
+	SetClipboard([]byte)
+
+	// GetClipboard is used to request the clipboard contents.  It may be ignored.
+	// If the terminal is willing, it will be post the clipboard contents using an
+	// EventPaste with the clipboard content as the Data() field.  Terminals may
+	// prevent this for security reasons.
+	GetClipboard()
 }
 
 // NewScreen returns a default Screen suitable for the user's terminal
@@ -343,6 +354,8 @@ type screenImpl interface {
 	SetSize(int, int)
 	SetTitle(string)
 	Tty() (Tty, bool)
+	SetClipboard([]byte)
+	GetClipboard()
 
 	// Following methods are not part of the Screen api, but are used for interaction with
 	// the common layer code.

simulation.go

@@ -61,8 +61,11 @@ type SimulationScreen interface {
 	// GetCursor returns the cursor details.
 	GetCursor() (x int, y int, visible bool)
 
-	// GetTitle gets the set title
+	// GetTitle gets the previously set title.
 	GetTitle() string
+
+	// GetClipboardData gets the actual data for the clipboard.
+	GetClipboardData() []byte
 }
 
 // SimCell represents a simulated screen cell.  The purpose of this
@@ -102,6 +105,7 @@ type simscreen struct {
 	fillstyle Style
 	fallback  map[rune]string
 	title     string
+	clipboard []byte
 
 	Screen
 	sync.Mutex
@@ -507,3 +511,18 @@ func (s *simscreen) SetTitle(title string) {
 func (s *simscreen) GetTitle() string {
 	return s.title
 }
+
+func (s *simscreen) SetClipboard(data []byte) {
+	s.clipboard = data
+}
+
+func (s *simscreen) GetClipboard() {
+	if s.clipboard != nil {
+		ev := NewEventClipboard(s.clipboard)
+		s.postEvent(ev)
+	}
+}
+
+func (s *simscreen) GetClipboardData() []byte {
+	return s.clipboard
+}

tscreen.go

@@ -19,6 +19,7 @@ package tcell
 
 import (
 	"bytes"
+	"encoding/base64"
 	"errors"
 	"io"
 	"os"
@@ -175,6 +176,7 @@ type tScreen struct {
 	saveTitle    string
 	restoreTitle string
 	title        string
+	setClipboard string
 
 	sync.Mutex
 }
@@ -447,7 +449,13 @@ func (t *tScreen) prepareExtendedOSC() {
 		t.restoreTitle = "\x1b[23;2t"
 		// this also tries to request that UTF-8 is allowed in the title
 		t.setTitle = "\x1b[>2t\x1b]2;%p1%s\x1b\\"
+	}
 
+	if t.setClipboard == "" && t.ti.XTermLike {
+		// this string takes a base64 string and sends it to the clipboard.
+		// it will also be able to retrieve the clipboard using "?" as the
+		// sent string, when we support that.
+		t.setClipboard = "\x1b]52;c;%p1%s\x1b\\"
 	}
 }
 
@@ -499,6 +507,11 @@ func (t *tScreen) prepareKey(key Key, val string) {
 
 func (t *tScreen) prepareKeys() {
 	ti := t.ti
+	if strings.HasPrefix(ti.Name, "xterm") {
+		// assume its some form of XTerm clone
+		t.ti.XTermLike = true
+		ti.XTermLike = true
+	}
 	t.prepareKey(KeyBackspace, ti.KeyBackspace)
 	t.prepareKey(KeyF1, ti.KeyF1)
 	t.prepareKey(KeyF2, ti.KeyF2)
@@ -1499,6 +1512,61 @@ func (t *tScreen) parseFocus(buf *bytes.Buffer, evs *[]Event) (bool, bool) {
 	return true, false
 }
 
+func (t *tScreen) parseClipboard(buf *bytes.Buffer, evs *[]Event) (bool, bool) {
+	b := buf.Bytes()
+	state := 0
+	prefix := []byte("\x1b]52;c;")
+
+	if len(prefix) >= len(b) {
+		if bytes.HasPrefix(prefix, b) {
+			// inconclusive so far
+			return true, false
+		}
+		// definitely not a match
+		return false, false
+	}
+	b = b[len(prefix):]
+
+	for _, c := range b {
+		// valid base64 digits
+		if (state == 0) {
+			if (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') || (c == '+') || (c == '/') || (c == '=') {
+				continue
+			}
+			if (c == '\x1b') {
+				state = 1
+				continue
+			}
+			if (c == '\a') {
+				// matched with BEL instead of ST
+				b = b[:len(b)-1] // drop the trailing BEL
+				decoded := make([]byte, base64.StdEncoding.DecodedLen(len(b)))
+				if num, err := base64.StdEncoding.Decode(decoded, b); err == nil {
+					*evs = append(*evs, NewEventClipboard(decoded[:num]))
+				}
+				_, _ = buf.ReadBytes('\a')
+				return true, true
+			}
+			return false, false
+		}
+		if (state == 1)  {
+			if (c == '\\') {
+				b = b[:len(b)-2] // drop the trailing ST (\x1b\\)
+				// now decode the data
+				decoded := make([]byte, base64.StdEncoding.DecodedLen(len(b)))
+				if num, err := base64.StdEncoding.Decode(decoded, b); err == nil {
+					*evs = append(*evs, NewEventClipboard(decoded[:num]))
+				}
+				_, _ = buf.ReadBytes('\\')
+				return true, true
+			}
+			return false, false
+		}
+	}
+	// not enough data yet (not terminated)
+	return true, false
+}
+
 // parseXtermMouse is like parseSgrMouse, but it parses a legacy
 // X11 mouse record.
 func (t *tScreen) parseXtermMouse(buf *bytes.Buffer, evs *[]Event) (bool, bool) {
@@ -1702,6 +1770,14 @@ func (t *tScreen) collectEventsFromInput(buf *bytes.Buffer, expire bool) []Event
 			}
 		}
 
+		if t.setClipboard != "" {
+			if part, comp := t.parseClipboard(buf, &res); comp {
+				continue
+			} else if part {
+				partials++
+			}
+		}
+
 		if partials == 0 || expire {
 			if b[0] == '\x1b' {
 				if len(b) == 1 {
@@ -2053,3 +2129,21 @@ func (t *tScreen) SetTitle(title string) {
 	}
 	t.Unlock()
 }
+
+func (t *tScreen) SetClipboard(data []byte) {
+	// Post binary data to the system clipboard.  It might be UTF-8, it might not be.
+	t.Lock()
+	if t.setClipboard != "" {
+		encoded := base64.StdEncoding.EncodeToString(data)
+		t.TPuts(t.ti.TParm(t.setClipboard, encoded))
+	}
+	t.Unlock()
+}
+
+func (t *tScreen) GetClipboard() {
+	t.Lock()
+	if t.setClipboard != "" {
+		t.TPuts(t.ti.TParm(t.setClipboard, "?"))
+	}
+	t.Unlock()
+}