fix editor

vendor/github.com/jesseduffield/gocui/text_area.go

@@ -0,0 +1,209 @@
+package gocui
+
+import "github.com/mattn/go-runewidth"
+
+type TextArea struct {
+	content   []rune
+	cursor    int
+	overwrite bool
+}
+
+func (self *TextArea) TypeRune(r rune) {
+	if self.overwrite && !self.atEnd() {
+		self.content[self.cursor] = r
+	} else {
+		self.content = append(
+			self.content[:self.cursor],
+			append([]rune{r}, self.content[self.cursor:]...)...,
+		)
+	}
+
+	self.cursor++
+}
+
+func (self *TextArea) BackSpaceChar() {
+	if self.cursor == 0 {
+		return
+	}
+
+	self.content = append(self.content[:self.cursor-1], self.content[self.cursor:]...)
+	self.cursor--
+}
+
+func (self *TextArea) DeleteChar() {
+	if self.atEnd() {
+		return
+	}
+
+	self.content = append(self.content[:self.cursor], self.content[self.cursor+1:]...)
+}
+
+func (self *TextArea) MoveCursorLeft() {
+	if self.cursor == 0 {
+		return
+	}
+
+	self.cursor--
+}
+
+func (self *TextArea) MoveCursorRight() {
+	if self.cursor == len(self.content) {
+		return
+	}
+
+	self.cursor++
+}
+
+func (self *TextArea) MoveCursorUp() {
+	x, y := self.GetCursorXY()
+	self.SetCursor2D(x, y-1)
+}
+
+func (self *TextArea) MoveCursorDown() {
+	x, y := self.GetCursorXY()
+	self.SetCursor2D(x, y+1)
+}
+
+func (self *TextArea) GetContent() string {
+	return string(self.content)
+}
+
+func (self *TextArea) ToggleOverwrite() {
+	self.overwrite = !self.overwrite
+}
+
+func (self *TextArea) atEnd() bool {
+	return self.cursor == len(self.content)
+}
+
+func (self *TextArea) DeleteToStartOfLine() {
+	// copying vim's logic: if you're at the start of the line, you delete the newline
+	// character and go to the end of the previous line
+	if self.atLineStart() {
+		if self.cursor == 0 {
+			return
+		}
+
+		self.content = append(self.content[:self.cursor-1], self.content[self.cursor:]...)
+		self.cursor--
+		return
+	}
+
+	// otherwise, you delete everything up to the start of the current line, without
+	// deleting the newline character
+	newlineIndex := self.closestNewlineOnLeft()
+	self.content = append(self.content[:newlineIndex+1], self.content[self.cursor:]...)
+	self.cursor = newlineIndex + 1
+}
+
+func (self *TextArea) GoToStartOfLine() {
+	if self.atLineStart() {
+		return
+	}
+
+	// otherwise, you delete everything up to the start of the current line, without
+	// deleting the newline character
+	newlineIndex := self.closestNewlineOnLeft()
+	self.cursor = newlineIndex + 1
+}
+
+func (self *TextArea) closestNewlineOnLeft() int {
+	newlineIndex := -1
+
+	for i, r := range self.content[0:self.cursor] {
+		if r == '\n' {
+			newlineIndex = i
+		}
+	}
+
+	return newlineIndex
+}
+
+func (self *TextArea) GoToEndOfLine() {
+	if self.atEnd() {
+		return
+	}
+
+	self.cursor = self.closestNewlineOnRight()
+}
+
+func (self *TextArea) closestNewlineOnRight() int {
+	for i, r := range self.content[self.cursor:] {
+		if r == '\n' {
+			return self.cursor + i
+		}
+	}
+
+	return len(self.content)
+}
+
+func (self *TextArea) atLineStart() bool {
+	return self.cursor == 0 ||
+		(len(self.content) > self.cursor-1 && self.content[self.cursor-1] == '\n')
+}
+
+func (self *TextArea) GetCursorXY() (int, int) {
+	cursorX := 0
+	cursorY := 0
+	for _, r := range self.content[0:self.cursor] {
+		if r == '\n' {
+			cursorY++
+			cursorX = 0
+		} else {
+			chWidth := runewidth.RuneWidth(r)
+			cursorX += chWidth
+		}
+	}
+
+	return cursorX, cursorY
+}
+
+// takes an x,y position and maps it to a 1D cursor position
+func (self *TextArea) SetCursor2D(x int, y int) {
+	if y < 0 {
+		y = 0
+	}
+	if x < 0 {
+		x = 0
+	}
+
+	newCursor := 0
+	for _, r := range self.content {
+		if x <= 0 && y == 0 {
+			self.cursor = newCursor
+			return
+		}
+
+		if r == '\n' {
+			if y == 0 {
+				self.cursor = newCursor
+				return
+			}
+			y--
+		} else if y == 0 {
+			chWidth := runewidth.RuneWidth(r)
+			x -= chWidth
+		}
+
+		newCursor++
+	}
+
+	// if we weren't able to run-down our arg, the user is trying to move out of
+	// bounds so we'll just return
+	if y > 0 {
+		return
+	}
+
+	self.cursor = newCursor
+}
+
+func (self *TextArea) Clear() {
+	self.content = []rune{}
+	self.cursor = 0
+}
+
+func (self *TextArea) TypeString(str string) {
+	for _, r := range str {
+		self.TypeRune(r)
+	}
+}