gemini-browser

simulation.go (10670B)

---

 // 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 tcell
 
 import (
 	"sync"
 	"unicode/utf8"
 
 	"golang.org/x/text/transform"
 )
 
 // NewSimulationScreen returns a SimulationScreen.  Note that
 // SimulationScreen is also a Screen.
 func NewSimulationScreen(charset string) SimulationScreen {
 	if charset == "" {
 		charset = "UTF-8"
 	}
 	ss := &simscreen{charset: charset}
 	ss.Screen = &baseScreen{screenImpl: ss}
 	return ss
 }
 
 // SimulationScreen represents a screen simulation.  This is intended to
 // be a superset of normal Screens, but also adds some important interfaces
 // for testing.
 type SimulationScreen interface {
 	Screen
 
 	// InjectKeyBytes injects a stream of bytes corresponding to
 	// the native encoding (see charset).  It turns true if the entire
 	// set of bytes were processed and delivered as KeyEvents, false
 	// if any bytes were not fully understood.  Any bytes that are not
 	// fully converted are discarded.
 	InjectKeyBytes(buf []byte) bool
 
 	// InjectKey injects a key event.  The rune is a UTF-8 rune, post
 	// any translation.
 	InjectKey(key Key, r rune, mod ModMask)
 
 	// InjectMouse injects a mouse event.
 	InjectMouse(x, y int, buttons ButtonMask, mod ModMask)
 
 	// GetContents returns screen contents as an array of
 	// cells, along with the physical width & height.   Note that the
 	// physical contents will be used until the next time SetSize()
 	// is called.
 	GetContents() (cells []SimCell, width int, height int)
 
 	// GetCursor returns the cursor details.
 	GetCursor() (x int, y int, visible bool)
 
 	// 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
 // is to track on screen content.
 type SimCell struct {
 	// Bytes is the actual character bytes.  Normally this is
 	// rune data, but it could be be data in another encoding system.
 	Bytes []byte
 
 	// Style is the style used to display the data.
 	Style Style
 
 	// Runes is the list of runes, unadulterated, in UTF-8.
 	Runes []rune
 }
 
 type simscreen struct {
 	physw int
 	physh int
 	fini  bool
 	style Style
 	evch  chan Event
 	quit  chan struct{}
 
 	front     []SimCell
 	back      CellBuffer
 	clear     bool
 	cursorx   int
 	cursory   int
 	cursorvis bool
 	mouse     bool
 	paste     bool
 	charset   string
 	encoder   transform.Transformer
 	decoder   transform.Transformer
 	fillchar  rune
 	fillstyle Style
 	fallback  map[rune]string
 	title     string
 	clipboard []byte
 
 	Screen
 	sync.Mutex
 }
 
 func (s *simscreen) Init() error {
 	s.evch = make(chan Event, 10)
 	s.quit = make(chan struct{})
 	s.fillchar = 'X'
 	s.fillstyle = StyleDefault
 	s.mouse = false
 	s.physw = 80
 	s.physh = 25
 	s.cursorx = -1
 	s.cursory = -1
 	s.style = StyleDefault
 
 	if enc := GetEncoding(s.charset); enc != nil {
 		s.encoder = enc.NewEncoder()
 		s.decoder = enc.NewDecoder()
 	} else {
 		return ErrNoCharset
 	}
 
 	s.front = make([]SimCell, s.physw*s.physh)
 	s.back.Resize(80, 25)
 
 	// default fallbacks
 	s.fallback = make(map[rune]string)
 	for k, v := range RuneFallbacks {
 		s.fallback[k] = v
 	}
 	return nil
 }
 
 func (s *simscreen) Fini() {
 	s.Lock()
 	s.fini = true
 	s.back.Resize(0, 0)
 	s.Unlock()
 	if s.quit != nil {
 		close(s.quit)
 	}
 	s.physw = 0
 	s.physh = 0
 	s.front = nil
 }
 
 func (s *simscreen) SetStyle(style Style) {
 	s.Lock()
 	s.style = style
 	s.Unlock()
 }
 
 func (s *simscreen) drawCell(x, y int) int {
 
 	mainc, combc, style, width := s.back.GetContent(x, y)
 	if !s.back.Dirty(x, y) {
 		return width
 	}
 	if x >= s.physw || y >= s.physh || x < 0 || y < 0 {
 		return width
 	}
 	simc := &s.front[(y*s.physw)+x]
 
 	if style == StyleDefault {
 		style = s.style
 	}
 	simc.Style = style
 	simc.Runes = append([]rune{mainc}, combc...)
 
 	// now emit runes - taking care to not overrun width with a
 	// wide character, and to ensure that we emit exactly one regular
 	// character followed up by any residual combing characters
 
 	simc.Bytes = nil
 
 	if x > s.physw-width {
 		simc.Runes = []rune{' '}
 		simc.Bytes = []byte{' '}
 		return width
 	}
 
 	lbuf := make([]byte, 12)
 	ubuf := make([]byte, 12)
 	nout := 0
 
 	for _, r := range simc.Runes {
 
 		l := utf8.EncodeRune(ubuf, r)
 
 		nout, _, _ = s.encoder.Transform(lbuf, ubuf[:l], true)
 
 		if nout == 0 || lbuf[0] == '\x1a' {
 
 			// skip combining
 
 			if subst, ok := s.fallback[r]; ok {
 				simc.Bytes = append(simc.Bytes,
 					[]byte(subst)...)
 
 			} else if r >= ' ' && r <= '~' {
 				simc.Bytes = append(simc.Bytes, byte(r))
 
 			} else if simc.Bytes == nil {
 				simc.Bytes = append(simc.Bytes, '?')
 			}
 		} else {
 			simc.Bytes = append(simc.Bytes, lbuf[:nout]...)
 		}
 	}
 	s.back.SetDirty(x, y, false)
 	return width
 }
 
 func (s *simscreen) ShowCursor(x, y int) {
 	s.Lock()
 	s.cursorx, s.cursory = x, y
 	s.showCursor()
 	s.Unlock()
 }
 
 func (s *simscreen) HideCursor() {
 	s.ShowCursor(-1, -1)
 }
 
 func (s *simscreen) showCursor() {
 
 	x, y := s.cursorx, s.cursory
 	if x < 0 || y < 0 || x >= s.physw || y >= s.physh {
 		s.cursorvis = false
 	} else {
 		s.cursorvis = true
 	}
 }
 
 func (s *simscreen) hideCursor() {
 	// does not update cursor position
 	s.cursorvis = false
 }
 
 func (s *simscreen) SetCursor(CursorStyle, Color) {}
 
 func (s *simscreen) Show() {
 	s.Lock()
 	s.resize()
 	s.draw()
 	s.Unlock()
 }
 
 func (s *simscreen) clearScreen() {
 	// We emulate a hardware clear by filling with a specific pattern
 	for i := range s.front {
 		s.front[i].Style = s.fillstyle
 		s.front[i].Runes = []rune{s.fillchar}
 		s.front[i].Bytes = []byte{byte(s.fillchar)}
 	}
 	s.clear = false
 }
 
 func (s *simscreen) draw() {
 	s.hideCursor()
 	if s.clear {
 		s.clearScreen()
 	}
 
 	w, h := s.back.Size()
 	for y := 0; y < h; y++ {
 		for x := 0; x < w; x++ {
 			width := s.drawCell(x, y)
 			x += width - 1
 		}
 	}
 	s.showCursor()
 }
 
 func (s *simscreen) EnableMouse(...MouseFlags) {
 	s.mouse = true
 }
 
 func (s *simscreen) DisableMouse() {
 	s.mouse = false
 }
 
 func (s *simscreen) EnablePaste() {
 	s.paste = true
 }
 
 func (s *simscreen) DisablePaste() {
 	s.paste = false
 }
 
 func (s *simscreen) EnableFocus() {
 }
 
 func (s *simscreen) DisableFocus() {
 }
 
 func (s *simscreen) Size() (int, int) {
 	s.Lock()
 	w, h := s.back.Size()
 	s.Unlock()
 	return w, h
 }
 
 func (s *simscreen) resize() {
 	w, h := s.physw, s.physh
 	ow, oh := s.back.Size()
 	if w != ow || h != oh {
 		s.back.Resize(w, h)
 		ev := NewEventResize(w, h)
 		s.postEvent(ev)
 	}
 }
 
 func (s *simscreen) Colors() int {
 	return 256
 }
 
 func (s *simscreen) postEvent(ev Event) {
 	select {
 	case s.evch <- ev:
 	case <-s.quit:
 	}
 }
 
 func (s *simscreen) InjectMouse(x, y int, buttons ButtonMask, mod ModMask) {
 	ev := NewEventMouse(x, y, buttons, mod)
 	s.postEvent(ev)
 }
 
 func (s *simscreen) InjectKey(key Key, r rune, mod ModMask) {
 	ev := NewEventKey(key, r, mod)
 	s.postEvent(ev)
 }
 
 func (s *simscreen) InjectKeyBytes(b []byte) bool {
 	failed := false
 
 outer:
 	for len(b) > 0 {
 		if b[0] >= ' ' && b[0] <= 0x7F {
 			// printable ASCII easy to deal with -- no encodings
 			ev := NewEventKey(KeyRune, rune(b[0]), ModNone)
 			s.postEvent(ev)
 			b = b[1:]
 			continue
 		}
 
 		if b[0] < 0x80 {
 			mod := ModNone
 			// No encodings start with low numbered values
 			if Key(b[0]) >= KeyCtrlA && Key(b[0]) <= KeyCtrlZ {
 				mod = ModCtrl
 			}
 			ev := NewEventKey(Key(b[0]), 0, mod)
 			s.postEvent(ev)
 			b = b[1:]
 			continue
 		}
 
 		utfb := make([]byte, len(b)*4) // worst case
 		for l := 1; l < len(b); l++ {
 			s.decoder.Reset()
 			nout, nin, _ := s.decoder.Transform(utfb, b[:l], true)
 
 			if nout != 0 {
 				r, _ := utf8.DecodeRune(utfb[:nout])
 				if r != utf8.RuneError {
 					ev := NewEventKey(KeyRune, r, ModNone)
 					s.postEvent(ev)
 				}
 				b = b[nin:]
 				continue outer
 			}
 		}
 		failed = true
 		b = b[1:]
 		continue
 	}
 
 	return !failed
 }
 
 func (s *simscreen) Sync() {
 	s.Lock()
 	s.clear = true
 	s.resize()
 	s.back.Invalidate()
 	s.draw()
 	s.Unlock()
 }
 
 func (s *simscreen) CharacterSet() string {
 	return s.charset
 }
 
 func (s *simscreen) SetSize(w, h int) {
 	s.Lock()
 	newc := make([]SimCell, w*h)
 	for row := 0; row < h && row < s.physh; row++ {
 		for col := 0; col < w && col < s.physw; col++ {
 			newc[(row*w)+col] = s.front[(row*s.physw)+col]
 		}
 	}
 	s.cursorx, s.cursory = -1, -1
 	s.physw, s.physh = w, h
 	s.front = newc
 	s.back.Resize(w, h)
 	s.Unlock()
 }
 
 func (s *simscreen) GetContents() ([]SimCell, int, int) {
 	s.Lock()
 	cells, w, h := s.front, s.physw, s.physh
 	s.Unlock()
 	return cells, w, h
 }
 
 func (s *simscreen) GetCursor() (int, int, bool) {
 	s.Lock()
 	x, y, vis := s.cursorx, s.cursory, s.cursorvis
 	s.Unlock()
 	return x, y, vis
 }
 
 func (s *simscreen) RegisterRuneFallback(r rune, subst string) {
 	s.Lock()
 	s.fallback[r] = subst
 	s.Unlock()
 }
 
 func (s *simscreen) UnregisterRuneFallback(r rune) {
 	s.Lock()
 	delete(s.fallback, r)
 	s.Unlock()
 }
 
 func (s *simscreen) CanDisplay(r rune, checkFallbacks bool) bool {
 
 	if enc := s.encoder; enc != nil {
 		nb := make([]byte, 6)
 		ob := make([]byte, 6)
 		num := utf8.EncodeRune(ob, r)
 
 		enc.Reset()
 		dst, _, err := enc.Transform(nb, ob[:num], true)
 		if dst != 0 && err == nil && nb[0] != '\x1A' {
 			return true
 		}
 	}
 	if !checkFallbacks {
 		return false
 	}
 	if _, ok := s.fallback[r]; ok {
 		return true
 	}
 	return false
 }
 
 func (s *simscreen) HasMouse() bool {
 	return false
 }
 
 func (s *simscreen) Resize(int, int, int, int) {}
 
 func (s *simscreen) HasKey(Key) bool {
 	return true
 }
 
 func (s *simscreen) Beep() error {
 	return nil
 }
 
 func (s *simscreen) Suspend() error {
 	return nil
 }
 
 func (s *simscreen) Resume() error {
 	return nil
 }
 
 func (s *simscreen) Tty() (Tty, bool) {
 	return nil, false
 }
 
 func (s *simscreen) GetCells() *CellBuffer {
 	return &s.back
 }
 
 func (s *simscreen) EventQ() chan Event {
 	return s.evch
 }
 
 func (s *simscreen) StopQ() <-chan struct{} {
 	return s.quit
 }
 
 func (s *simscreen) SetTitle(title string) {
 	s.title = title
 }
 
 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
 }