Add terminal pkg

2026-10-25 02:51:02 +00:00
parent f6ad634b70
commit 1aabbdfee7
3 changed files with 525 additions and 0 deletions
@@ -0,0 +1,276 @@
+package input
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"log/slog"
+	"os"
+	"unicode/utf8"
+)
+
+type Event struct {
+	Key  Key
+	Rune rune
+}
+
+type Reader struct {
+	buf    *bufio.Reader
+	events chan *Event
+	log    *slog.Logger
+}
+
+type Parameters struct {
+	Chan chan *Event
+	In   *os.File
+	Log  *slog.Logger
+}
+
+func New(p Parameters) *Reader {
+	return &Reader{
+		buf:    bufio.NewReader(p.In),
+		events: p.Chan,
+		log:    p.Log,
+	}
+}
+
+// send delivers e, or gives up when ctx is done.
+func (i *Reader) send(ctx context.Context, e *Event) error {
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case i.events <- e:
+		return nil
+	}
+}
+
+// TODO: reading one rune at a time is slow, especially when pasting large
+// quantities of text into the active buffer. It would be nice to take more
+// input at once, while still being able to handle escape sequences without
+// too many edge cases.
+func (i *Reader) Run(ctx context.Context) error {
+	for {
+		select {
+		case <-ctx.Done():
+			return nil
+		default:
+			r, size, err := i.buf.ReadRune()
+			if err != nil {
+				return fmt.Errorf("failed to read: %w", err)
+			}
+			i.log.DebugContext(
+				ctx,
+				"read rune",
+				slog.String("rune", string(r)),
+				slog.Any("bytes", []byte(string(r))),
+				slog.Int("size", size),
+			)
+			switch r {
+			case utf8.RuneError:
+				i.log.ErrorContext(
+					ctx,
+					"rune error",
+					slog.String("rune", string(r)),
+					slog.Int("size", size),
+				)
+
+				// Handle escape sequences.
+			case Escape:
+				if err := i.parseEscapeSequence(ctx); err != nil {
+					return fmt.Errorf(
+						"failed to read: %w", err,
+					)
+				}
+
+			default:
+				if err := i.send(ctx, &Event{Rune: r}); err != nil {
+					return err
+				}
+			}
+		}
+	}
+}
+
+func (i *Reader) parseEscapeSequence(ctx context.Context) error {
+	r1, _, err := i.buf.ReadRune()
+	if err != nil {
+		return fmt.Errorf("failed to read: %w", err)
+	}
+
+	// Ignore invalid escape sequences.
+	if r1 != '[' && r1 != 'O' {
+		if err := i.send(ctx, &Event{Rune: r1}); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	// We've received an input of Esc + [ or Esc + O.
+	// Determine the escape sequence.
+	r2, _, err := i.buf.ReadRune()
+	if err != nil {
+		return fmt.Errorf("failed to read: %w", err)
+
+	}
+
+	// Check letter escape sequences.
+	switch r2 {
+	case 'A':
+		if err := i.send(ctx, &Event{Key: Up}); err != nil {
+			return err
+		}
+		return nil
+	case 'B':
+		if err := i.send(ctx, &Event{Key: Down}); err != nil {
+			return err
+		}
+		return nil
+	case 'C':
+		if err := i.send(ctx, &Event{Key: Right}); err != nil {
+			return err
+		}
+		return nil
+	case 'D':
+		if err := i.send(ctx, &Event{Key: Left}); err != nil {
+			return err
+		}
+		return nil
+
+	case 'O':
+		r3, _, err := i.buf.ReadRune()
+		if err != nil {
+			return fmt.Errorf("failed to read: %w", err)
+		}
+		switch r3 {
+		case 'P': // F1
+			return nil
+		case 'Q': // F2
+			return nil
+		case 'R': // F3
+			return nil
+		case 'S': // F4
+			return nil
+		default:
+			// No match.
+			if err := i.send(ctx, &Event{Rune: r1}); err != nil {
+				return err
+			}
+			if err := i.send(ctx, &Event{Rune: r2}); err != nil {
+				return err
+			}
+			if err := i.send(ctx, &Event{Rune: r3}); err != nil {
+				return err
+			}
+			return nil
+		}
+	}
+
+	// Check for single digit numerical escape sequences.
+	r3, _, err := i.buf.ReadRune()
+	if err != nil {
+		return fmt.Errorf("failed to read: %w", err)
+	}
+	switch {
+	case r2 == '1' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: Home}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '2' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: Insert}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '3' && r3 == '~':
+		if err := i.send(ctx, &Event{Rune: Delete}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '4' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: End}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '5' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: PageUp}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '6' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: PageDown}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '7' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: Home}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '8' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: End}); err != nil {
+			return err
+		}
+		return nil
+	case r2 == '9' && r3 == '~':
+		if err := i.send(ctx, &Event{Key: End}); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	// Check for double digit numerical escape sequences.
+	r4, _, err := i.buf.ReadRune()
+	if err != nil {
+		return fmt.Errorf("failed to read: %w", err)
+	}
+	switch {
+	case r2 == '1' && r3 == '0' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '1' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '2' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '3' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '4' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '4' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '6' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '7' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '8' && r4 == '~':
+		return nil
+	case r2 == '1' && r3 == '9' && r4 == '~':
+		return nil
+	case r2 == '2' && r3 == '0' && r4 == '~':
+		return nil
+	case r2 == '2' && r3 == '1' && r4 == '~':
+		return nil
+	case r2 == '2' && r3 == '2' && r4 == '~':
+		return nil
+	case r2 == '2' && r3 == '3' && r4 == '~':
+		return nil
+	case r2 == '2' && r3 == '4' && r4 == '~':
+		return nil
+	case r4 == '~':
+		return nil
+	}
+
+	// No match.
+	if err := i.send(ctx, &Event{Rune: r1}); err != nil {
+		return err
+	}
+	if err := i.send(ctx, &Event{Rune: r2}); err != nil {
+		return err
+	}
+	if err := i.send(ctx, &Event{Rune: r3}); err != nil {
+		return err
+	}
+	if err := i.send(ctx, &Event{Rune: r4}); err != nil {
+		return err
+	}
+
+	return nil
+}
@@ -0,0 +1,151 @@
+package input
+
+type Key uint8
+
+const (
+	Down Key = iota + 1
+	Left
+	Right
+	Up
+	End
+	Home
+	Insert
+	PageDown
+	PageUp
+)
+
+const Control rune = 0x1f
+
+const (
+	// Control Characters
+	Null                   rune = 0
+	StartOfHeading         rune = 1
+	StartOfText            rune = 2
+	EndOfText              rune = 3
+	EndOfTransmission      rune = 4
+	Enquiry                rune = 5
+	Acknowledgment         rune = 6
+	Bell                   rune = 7
+	Backspace              rune = 8
+	HorizontalTab          rune = 9
+	LineFeed               rune = 10
+	VerticalTab            rune = 11
+	FormFeed               rune = 12
+	CarriageReturn         rune = 13
+	ShiftOut               rune = 14
+	ShiftIn                rune = 15
+	DataLineEscape         rune = 16
+	DeviceControl1         rune = 17
+	DeviceControl2         rune = 18
+	DeviceControl3         rune = 19
+	DeviceControl4         rune = 20
+	NegativeAcknowledgment rune = 21
+	SynchronousIdle        rune = 22
+	EndOfTransmitBlock     rune = 23
+	Cancel                 rune = 24
+	EndOfMedium            rune = 25
+	Substitute             rune = 26
+	Escape                 rune = 27
+	FileSeparator          rune = 28
+	GroupSeparator         rune = 29
+	RecordSeparator        rune = 30
+	UnitSeparator          rune = 31
+
+	// Printable Characters
+	Space            rune = 32
+	ExclamationMark  rune = 33
+	DoubleQuote      rune = 34
+	Number           rune = 35
+	Dollar           rune = 36
+	Percentage       rune = 37
+	Ampersand        rune = 38
+	SingleQuote      rune = 39
+	LeftParenthesis  rune = 40
+	RightParenthesis rune = 41
+	Asterisk         rune = 42
+	Plus             rune = 43
+	Comma            rune = 44
+	Hyphen           rune = 45
+	Period           rune = 46
+	ForwardSlash     rune = 47
+	Zero             rune = 48
+	One              rune = 49
+	Two              rune = 50
+	Three            rune = 51
+	Four             rune = 52
+	Five             rune = 53
+	Six              rune = 54
+	Seven            rune = 55
+	Eight            rune = 56
+	Nine             rune = 57
+	Colon            rune = 58
+	Semicolon        rune = 59
+	LessThan         rune = 60
+	Equals           rune = 61
+	GreaterThan      rune = 62
+	QuestionMark     rune = 63
+	At               rune = 64
+	UpperA           rune = 65
+	UpperB           rune = 66
+	UpperC           rune = 67
+	UpperD           rune = 68
+	UpperE           rune = 69
+	UpperF           rune = 70
+	UpperG           rune = 71
+	UpperH           rune = 72
+	UpperI           rune = 73
+	UpperJ           rune = 74
+	UpperK           rune = 75
+	UpperL           rune = 76
+	UpperM           rune = 77
+	UpperN           rune = 78
+	UpperO           rune = 79
+	UpperP           rune = 80
+	UpperQ           rune = 81
+	UpperR           rune = 82
+	UpperS           rune = 83
+	UpperT           rune = 84
+	UpperU           rune = 85
+	UpperV           rune = 86
+	UpperW           rune = 87
+	UpperX           rune = 88
+	UpperY           rune = 89
+	UpperZ           rune = 90
+	LeftBracket      rune = 91
+	Backslash        rune = 92
+	RightBracket     rune = 93
+	Caret            rune = 94
+	Underscore       rune = 95
+	Grave            rune = 96
+	LowerA           rune = 97
+	LowerB           rune = 98
+	LowerC           rune = 99
+	LowerD           rune = 100
+	LowerE           rune = 101
+	LowerF           rune = 102
+	LowerG           rune = 103
+	LowerH           rune = 104
+	LowerI           rune = 105
+	LowerJ           rune = 106
+	LowerK           rune = 107
+	LowerL           rune = 108
+	LowerM           rune = 109
+	LowerN           rune = 110
+	LowerO           rune = 111
+	LowerP           rune = 112
+	LowerQ           rune = 113
+	LowerR           rune = 114
+	LowerS           rune = 115
+	LowerT           rune = 116
+	LowerU           rune = 117
+	LowerV           rune = 118
+	LowerW           rune = 119
+	LowerX           rune = 120
+	LowerY           rune = 121
+	LowerZ           rune = 122
+	LeftBrace        rune = 123
+	VerticalBar      rune = 124
+	RightBrace       rune = 125
+	Tilde            rune = 126
+	Delete           rune = 127
+)
@@ -0,0 +1,98 @@
+package terminal
+
+import (
+	"fmt"
+	"syscall"
+	"unsafe"
+)
+
+const (
+	ClearScreen   = "\u001Bc"
+	CursorHide    = "\u001B[?25l"
+	CursorShow    = "\u001B[?25h"
+	CursorTopLeft = "\u001B[H"
+	EraseLine     = "\u001B[K"
+
+	SetCursorFmt = "\u001B[%d;%dH"
+)
+
+type Terminal struct {
+	fd      uintptr
+	termios *syscall.Termios
+}
+
+type Size struct {
+	Rows    uint16
+	Columns uint16
+	XPixels uint16
+	YPixels uint16
+}
+
+func New(fd uintptr) (*Terminal, error) {
+	var t = &Terminal{
+		fd:      fd,
+		termios: &syscall.Termios{},
+	}
+
+	if _, _, err := syscall.Syscall(
+		syscall.SYS_IOCTL,
+		fd,
+		syscall.TCGETS,
+		uintptr(unsafe.Pointer(t.termios)),
+	); err != 0 {
+		return nil, fmt.Errorf("ioctl syscall: %w", err)
+	}
+
+	return t, nil
+}
+
+// Reset the terminal into the original termios.
+func (t *Terminal) Reset() error {
+	if _, _, err := syscall.Syscall(
+		syscall.SYS_IOCTL,
+		t.fd,
+		uintptr(syscall.TCSETS),
+		uintptr(unsafe.Pointer(t.termios)),
+	); err != 0 {
+		return fmt.Errorf("ioctl syscall: %w", err)
+	}
+
+	return nil
+}
+
+// SetRaw enables raw mode.
+func (t *Terminal) SetRaw() error {
+	var termios = *t.termios
+	termios.Iflag &^= syscall.IGNBRK | syscall.BRKINT | syscall.PARMRK | syscall.ISTRIP | syscall.INLCR | syscall.IGNCR | syscall.ICRNL | syscall.IXON
+	termios.Oflag &^= syscall.OPOST
+	termios.Lflag &^= syscall.ECHO | syscall.ECHONL | syscall.ICANON | syscall.ISIG | syscall.IEXTEN
+	termios.Cflag &^= syscall.CSIZE | syscall.PARENB
+	termios.Cflag |= syscall.CS8
+	termios.Cc[syscall.VMIN] = 1
+	termios.Cc[syscall.VTIME] = 0
+
+	if _, _, err := syscall.Syscall(
+		syscall.SYS_IOCTL,
+		t.fd,
+		uintptr(syscall.TCSETS),
+		uintptr(unsafe.Pointer(&termios)),
+	); err != 0 {
+		return fmt.Errorf("ioctl syscall: %w", err)
+	}
+
+	return nil
+}
+
+func (t *Terminal) Size() (*Size, error) {
+	var size = &Size{}
+	if _, _, err := syscall.Syscall(
+		syscall.SYS_IOCTL,
+		t.fd,
+		syscall.TIOCGWINSZ,
+		uintptr(unsafe.Pointer(size)),
+	); err != 0 {
+		return nil, fmt.Errorf("ioctl syscall: %w", err)
+	}
+
+	return size, nil
+}