feat: bracketed paste (charmbracelet#397)

* feat: bracketed paste

This introduces support for input via bracketed paste, where escape
characters in the pasted input are not interpreted.

Pasted input are marked as a special field in the KeyMsg. This is
useful because pasted input may need sanitation in individual widgets.

* fix(key): support bracketed paste with short reads

Some terminal emulators feed the bracketed paste data in multiple
chunks, which may not be aligned on a 256 byte boundary. So it's
possible for `input.Read` to return less than 256 bytes read
but while there's still more data to be read to complete a bracketed
paste input.

---------

Co-authored-by: Christian Muehlhaeuser <muesli@gmail.com>

examples/simple/testdata/TestApp.golden

@@ -1,3 +1,3 @@
-[?25lHi. This program will exit in 10 seconds. To quit sooner press any key
+[?25l[?2004hHi. This program will exit in 10 seconds. To quit sooner press any key
 Hi. This program will exit in 9 seconds. To quit sooner press any key.
-[?25h[?1002l[?1003l[?1006l
+[?2004l[?25h[?1002l[?1003l[?1006l

key.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"regexp"
+	"strings"
 	"unicode/utf8"
 )
 
@@ -54,6 +55,7 @@ type Key struct {
 	Type  KeyType
 	Runes []rune
 	Alt   bool
+	Paste bool
 }
 
 // String returns a friendly string representation for a key. It's safe (and
@@ -63,15 +65,28 @@ type Key struct {
 //	fmt.Println(k)
 //	// Output: enter
 func (k Key) String() (str string) {
+	var buf strings.Builder
 	if k.Alt {
-		str += "alt+"
+		buf.WriteString("alt+")
 	}
 	if k.Type == KeyRunes {
-		str += string(k.Runes)
-		return str
+		if k.Paste {
+			// Note: bubbles/keys bindings currently do string compares to
+			// recognize shortcuts. Since pasted text should never activate
+			// shortcuts, we need to ensure that the binding code doesn't
+			// match Key events that result from pastes. We achieve this
+			// here by enclosing pastes in '[...]' so that the string
+			// comparison in Matches() fails in that case.
+			buf.WriteByte('[')
+		}
+		buf.WriteString(string(k.Runes))
+		if k.Paste {
+			buf.WriteByte(']')
+		}
+		return buf.String()
 	} else if s, ok := keyNames[k.Type]; ok {
-		str += s
-		return str
+		buf.WriteString(s)
+		return buf.String()
 	}
 	return ""
 }
@@ -613,6 +628,13 @@ func detectOneMsg(b []byte, canHaveMoreData bool) (w int, msg Msg) {
 		}
 	}
 
+	// Detect bracketed paste.
+	var foundbp bool
+	foundbp, w, msg = detectBracketedPaste(b)
+	if foundbp {
+		return
+	}
+
 	// Detect escape sequence and control characters other than NUL,
 	// possibly with an escape character in front to mark the Alt
 	// modifier.

key_sequences.go

@@ -1,6 +1,10 @@
 package tea
 
-import "sort"
+import (
+	"bytes"
+	"sort"
+	"unicode/utf8"
+)
 
 // extSequences is used by the map-based algorithm below. It contains
 // the sequences plus their alternatives with an escape character
@@ -69,3 +73,47 @@ func detectSequence(input []byte) (hasSeq bool, width int, msg Msg) {
 
 	return false, 0, nil
 }
+
+// detectBracketedPaste detects an input pasted while bracketed
+// paste mode was enabled.
+//
+// Note: this function is a no-op if bracketed paste was not enabled
+// on the terminal, since in that case we'd never see this
+// particular escape sequence.
+func detectBracketedPaste(input []byte) (hasBp bool, width int, msg Msg) {
+	// Detect the start sequence.
+	const bpStart = "\x1b[200~"
+	if len(input) < len(bpStart) || string(input[:len(bpStart)]) != bpStart {
+		return false, 0, nil
+	}
+
+	// Skip over the start sequence.
+	input = input[len(bpStart):]
+
+	// If we saw the start sequence, then we must have an end sequence
+	// as well. Find it.
+	const bpEnd = "\x1b[201~"
+	idx := bytes.Index(input, []byte(bpEnd))
+	inputLen := len(bpStart) + idx + len(bpEnd)
+	if idx == -1 {
+		// We have encountered the end of the input buffer without seeing
+		// the marker for the end of the bracketed paste.
+		// Tell the outer loop we have done a short read and we want more.
+		return true, 0, nil
+	}
+
+	// The paste is everything in-between.
+	paste := input[:idx]
+
+	// All there is in-between is runes, not to be interpreted further.
+	k := Key{Type: KeyRunes, Paste: true}
+	for len(paste) > 0 {
+		r, w := utf8.DecodeRune(paste)
+		if r != utf8.RuneError {
+			k.Runes = append(k.Runes, r)
+		}
+		paste = paste[w:]
+	}
+
+	return true, inputLen, KeyMsg(k)
+}

key_test.go

@@ -434,23 +434,25 @@ func TestReadInput(t *testing.T) {
 			[]byte{'\x1b', '\x1b'},
 			[]Msg{KeyMsg{Type: KeyEsc, Alt: true}},
 		},
-		// Bracketed paste does not work yet.
-		{"?CSI[50 48 48 126]? a   b ?CSI[50 48 49 126]?",
+		{"[a b] o",
 			[]byte{
 				'\x1b', '[', '2', '0', '0', '~',
 				'a', ' ', 'b',
+				'\x1b', '[', '2', '0', '1', '~',
+				'o',
+			},
+			[]Msg{
+				KeyMsg{Type: KeyRunes, Runes: []rune("a b"), Paste: true},
+				KeyMsg{Type: KeyRunes, Runes: []rune("o")},
+			},
+		},
+		{"[a\x03\nb]",
+			[]byte{
+				'\x1b', '[', '2', '0', '0', '~',
+				'a', '\x03', '\n', 'b',
 				'\x1b', '[', '2', '0', '1', '~'},
 			[]Msg{
-				// What we expect once bracketed paste is recognized properly:
-				//
-				//  KeyMsg{Type: KeyRunes, Runes: []rune("a b")},
-				//
-				// What we get instead (for now):
-				unknownCSISequenceMsg{0x1b, 0x5b, 0x32, 0x30, 0x30, 0x7e},
-				KeyMsg{Type: KeyRunes, Runes: []rune{'a'}},
-				KeyMsg{Type: KeySpace, Runes: []rune{' '}},
-				KeyMsg{Type: KeyRunes, Runes: []rune{'b'}},
-				unknownCSISequenceMsg{0x1b, 0x5b, 0x32, 0x30, 0x31, 0x7e},
+				KeyMsg{Type: KeyRunes, Runes: []rune("a\x03\nb"), Paste: true},
 			},
 		},
 	}

nil_renderer.go

@@ -2,20 +2,23 @@ package tea
 
 type nilRenderer struct{}
 
-func (n nilRenderer) start()                  {}
-func (n nilRenderer) stop()                   {}
-func (n nilRenderer) kill()                   {}
-func (n nilRenderer) write(_ string)          {}
-func (n nilRenderer) repaint()                {}
-func (n nilRenderer) clearScreen()            {}
-func (n nilRenderer) altScreen() bool         { return false }
-func (n nilRenderer) enterAltScreen()         {}
-func (n nilRenderer) exitAltScreen()          {}
-func (n nilRenderer) showCursor()             {}
-func (n nilRenderer) hideCursor()             {}
-func (n nilRenderer) enableMouseCellMotion()  {}
-func (n nilRenderer) disableMouseCellMotion() {}
-func (n nilRenderer) enableMouseAllMotion()   {}
-func (n nilRenderer) disableMouseAllMotion()  {}
-func (n nilRenderer) enableMouseSGRMode()     {}
-func (n nilRenderer) disableMouseSGRMode()    {}
+func (n nilRenderer) start()                     {}
+func (n nilRenderer) stop()                      {}
+func (n nilRenderer) kill()                      {}
+func (n nilRenderer) write(_ string)             {}
+func (n nilRenderer) repaint()                   {}
+func (n nilRenderer) clearScreen()               {}
+func (n nilRenderer) altScreen() bool            { return false }
+func (n nilRenderer) enterAltScreen()            {}
+func (n nilRenderer) exitAltScreen()             {}
+func (n nilRenderer) showCursor()                {}
+func (n nilRenderer) hideCursor()                {}
+func (n nilRenderer) enableMouseCellMotion()     {}
+func (n nilRenderer) disableMouseCellMotion()    {}
+func (n nilRenderer) enableMouseAllMotion()      {}
+func (n nilRenderer) disableMouseAllMotion()     {}
+func (n nilRenderer) enableBracketedPaste()      {}
+func (n nilRenderer) disableBracketedPaste()     {}
+func (n nilRenderer) enableMouseSGRMode()        {}
+func (n nilRenderer) disableMouseSGRMode()       {}
+func (n nilRenderer) bracketedPasteActive() bool { return false }

options.go

@@ -101,6 +101,13 @@ func WithAltScreen() ProgramOption {
 	}
 }
 
+// WithoutBracketedPaste starts the program with bracketed paste disabled.
+func WithoutBracketedPaste() ProgramOption {
+	return func(p *Program) {
+		p.startupOptions |= withoutBracketedPaste
+	}
+}
+
 // WithMouseCellMotion starts the program with the mouse enabled in "cell
 // motion" mode.
 //

options_test.go

@@ -81,6 +81,10 @@ func TestOptions(t *testing.T) {
 			exercise(t, WithAltScreen(), withAltScreen)
 		})
 
+		t.Run("bracketed paste disabled", func(t *testing.T) {
+			exercise(t, WithoutBracketedPaste(), withoutBracketedPaste)
+		})
+
 		t.Run("ansi compression", func(t *testing.T) {
 			exercise(t, WithANSICompressor(), withANSICompressor)
 		})
@@ -115,8 +119,8 @@ func TestOptions(t *testing.T) {
 	})
 
 	t.Run("multiple", func(t *testing.T) {
-		p := NewProgram(nil, WithMouseAllMotion(), WithAltScreen(), WithInputTTY())
-		for _, opt := range []startupOptions{withMouseAllMotion, withAltScreen} {
+		p := NewProgram(nil, WithMouseAllMotion(), WithoutBracketedPaste(), WithAltScreen(), WithInputTTY())
+		for _, opt := range []startupOptions{withMouseAllMotion, withoutBracketedPaste, withAltScreen} {
 			if !p.startupOptions.has(opt) {
 				t.Errorf("expected startup options have %v, got %v", opt, p.startupOptions)
 			}

renderer.go

@@ -56,6 +56,17 @@ type renderer interface {
 
 	// disableMouseSGRMode disables mouse extended mode (SGR).
 	disableMouseSGRMode()
+
+	// enableBracketedPaste enables bracketed paste, where characters
+	// inside the input are not interpreted when pasted as a whole.
+	enableBracketedPaste()
+
+	// disableBracketedPaste disables bracketed paste.
+	disableBracketedPaste()
+
+	// bracketedPasteActive reports whether bracketed paste mode is
+	// currently enabled.
+	bracketedPasteActive() bool
 }
 
 // repaintMsg forces a full repaint.

screen.go

@@ -116,6 +116,34 @@ func ShowCursor() Msg {
 // this message with ShowCursor.
 type showCursorMsg struct{}
 
+// EnableBracketedPaste is a special command that tells the Bubble Tea program
+// to accept bracketed paste input.
+//
+// Note that bracketed paste will be automatically disabled when the
+// program quits.
+func EnableBracketedPaste() Msg {
+	return enableBracketedPasteMsg{}
+}
+
+// enableBracketedPasteMsg in an internal message signals that
+// bracketed paste should be enabled. You can send an
+// enableBracketedPasteMsg with EnableBracketedPaste.
+type enableBracketedPasteMsg struct{}
+
+// DisableBracketedPaste is a special command that tells the Bubble Tea program
+// to accept bracketed paste input.
+//
+// Note that bracketed paste will be automatically disabled when the
+// program quits.
+func DisableBracketedPaste() Msg {
+	return disableBracketedPasteMsg{}
+}
+
+// disableBracketedPasteMsg in an internal message signals that
+// bracketed paste should be disabled. You can send an
+// disableBracketedPasteMsg with DisableBracketedPaste.
+type disableBracketedPasteMsg struct{}
+
 // EnterAltScreen enters the alternate screen buffer, which consumes the entire
 // terminal window. ExitAltScreen will return the terminal to its former state.
 //

screen_test.go

@@ -14,42 +14,47 @@ func TestClearMsg(t *testing.T) {
 		{
 			name:     "clear_screen",
 			cmds:     []Cmd{ClearScreen},
-			expected: "\x1b[?25l\x1b[2J\x1b[1;1H\x1b[1;1Hsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[2J\x1b[1;1H\x1b[1;1Hsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 		{
 			name:     "altscreen",
 			cmds:     []Cmd{EnterAltScreen, ExitAltScreen},
-			expected: "\x1b[?25l\x1b[?1049h\x1b[2J\x1b[1;1H\x1b[1;1H\x1b[?25l\x1b[?1049l\x1b[?25lsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?1049h\x1b[2J\x1b[1;1H\x1b[1;1H\x1b[?25l\x1b[?1049l\x1b[?25lsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 		{
 			name:     "altscreen_autoexit",
 			cmds:     []Cmd{EnterAltScreen},
-			expected: "\x1b[?25l\x1b[?1049h\x1b[2J\x1b[1;1H\x1b[1;1H\x1b[?25lsuccess\r\n\x1b[2;0H\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l\x1b[?1049l\x1b[?25h",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?1049h\x1b[2J\x1b[1;1H\x1b[1;1H\x1b[?25lsuccess\r\n\x1b[2;0H\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l\x1b[?1049l\x1b[?25h",
 		},
 		{
 			name:     "mouse_cellmotion",
 			cmds:     []Cmd{EnableMouseCellMotion},
-			expected: "\x1b[?25l\x1b[?1002h\x1b[?1006hsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?1002h\x1b[?1006hsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 		{
 			name:     "mouse_allmotion",
 			cmds:     []Cmd{EnableMouseAllMotion},
-			expected: "\x1b[?25l\x1b[?1003h\x1b[?1006hsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?1003h\x1b[?1006hsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 		{
 			name:     "mouse_disable",
 			cmds:     []Cmd{EnableMouseAllMotion, DisableMouse},
-			expected: "\x1b[?25l\x1b[?1003h\x1b[?1006h\x1b[?1002l\x1b[?1003l\x1b[?1006lsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?1003h\x1b[?1006h\x1b[?1002l\x1b[?1003l\x1b[?1006lsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 		{
 			name:     "cursor_hide",
 			cmds:     []Cmd{HideCursor},
-			expected: "\x1b[?25l\x1b[?25lsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?25lsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 		{
 			name:     "cursor_hideshow",
 			cmds:     []Cmd{HideCursor, ShowCursor},
-			expected: "\x1b[?25l\x1b[?25l\x1b[?25hsuccess\r\n\x1b[0D\x1b[2K\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?25l\x1b[?25hsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
+		},
+		{
+			name:     "bp_stop_start",
+			cmds:     []Cmd{DisableBracketedPaste, EnableBracketedPaste},
+			expected: "\x1b[?25l\x1b[?2004h\x1b[?2004l\x1b[?2004hsuccess\r\n\x1b[0D\x1b[2K\x1b[?2004l\x1b[?25h\x1b[?1002l\x1b[?1003l\x1b[?1006l",
 		},
 	}
 
@@ -69,7 +74,7 @@ func TestClearMsg(t *testing.T) {
 			}
 
 			if buf.String() != test.expected {
-				t.Errorf("expected embedded sequence, got %q", buf.String())
+				t.Errorf("expected embedded sequence:\n%q\ngot:\n%q", test.expected, buf.String())
 			}
 		})
 	}