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// Copyright 2014 The gocui Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gocui
import (
"errors"
"github.com/mattn/go-runewidth"
)
const maxInt = int(^uint(0) >> 1)
// Editor interface must be satisfied by gocui editors.
type Editor interface {
Edit(v *View, key Key, ch rune, mod Modifier)
}
// The EditorFunc type is an adapter to allow the use of ordinary functions as
// Editors. If f is a function with the appropriate signature, EditorFunc(f)
// is an Editor object that calls f.
type EditorFunc func(v *View, key Key, ch rune, mod Modifier)
// Edit calls f(v, key, ch, mod)
func (f EditorFunc) Edit(v *View, key Key, ch rune, mod Modifier) {
f(v, key, ch, mod)
}
// DefaultEditor is the default editor.
var DefaultEditor Editor = EditorFunc(simpleEditor)
// simpleEditor is used as the default gocui editor.
func simpleEditor(v *View, key Key, ch rune, mod Modifier) {
switch {
case ch != 0 && mod == 0:
v.EditWrite(ch)
case key == KeySpace:
v.EditWrite(' ')
case key == KeyBackspace || key == KeyBackspace2:
v.EditDelete(true)
case key == KeyDelete:
v.EditDelete(false)
case key == KeyInsert:
v.Overwrite = !v.Overwrite
case key == KeyEnter:
v.EditNewLine()
case key == KeyArrowDown:
v.MoveCursor(0, 1, false)
case key == KeyArrowUp:
v.MoveCursor(0, -1, false)
case key == KeyArrowLeft:
v.MoveCursor(-1, 0, false)
case key == KeyArrowRight:
v.MoveCursor(1, 0, false)
}
}
// EditWrite writes a rune at the cursor position.
func (v *View) EditWrite(ch rune) {
w := runewidth.RuneWidth(ch)
v.writeRune(v.cx, v.cy, ch)
v.moveCursor(w, 0, true)
}
// EditDelete deletes a rune at the cursor position. back determines the
// direction.
func (v *View) EditDelete(back bool) {
x, y := v.ox+v.cx, v.oy+v.cy
if y < 0 {
return
} else if y >= len(v.viewLines) {
v.MoveCursor(-1, 0, true)
return
}
maxX, _ := v.Size()
if back {
if x == 0 { // start of the line
if y < 1 {
return
}
var maxPrevWidth int
if v.Wrap {
maxPrevWidth = maxX
} else {
maxPrevWidth = maxInt
}
if v.viewLines[y].linesX == 0 { // regular line
v.mergeLines(v.cy - 1)
if len(v.viewLines[y-1].line) < maxPrevWidth {
v.MoveCursor(-1, 0, true)
}
} else { // wrapped line
n, _ := v.deleteRune(len(v.viewLines[y-1].line)-1, v.cy-1)
v.MoveCursor(-n, 0, true)
}
} else { // middle/end of the line
n, _ := v.deleteRune(v.cx-1, v.cy)
v.MoveCursor(-n, 0, true)
}
} else {
if x == len(v.viewLines[y].line) { // end of the line
v.mergeLines(v.cy)
} else { // start/middle of the line
v.deleteRune(v.cx, v.cy)
}
}
}
// EditNewLine inserts a new line under the cursor.
func (v *View) EditNewLine() {
v.breakLine(v.cx, v.cy)
v.ox = 0
v.cy = v.cy + 1
v.cx = 0
}
// MoveCursor moves the cursor taking into account the width of the line/view,
// displacing the origin if necessary.
func (v *View) MoveCursor(dx, dy int, writeMode bool) {
ox, oy := v.cx+v.ox, v.cy+v.oy
x, y := ox+dx, oy+dy
if y < 0 || y >= len(v.viewLines) {
v.moveCursor(dx, dy, writeMode)
return
}
// Removing newline.
if x < 0 {
var prevLen int
if y-1 >= 0 && y-1 < len(v.viewLines) {
prevLen = lineWidth(v.viewLines[y-1].line)
}
v.MoveCursor(prevLen, -1, writeMode)
return
}
line := v.viewLines[y].line
var col int
var prevCol int
for i := range line {
prevCol = col
col += runewidth.RuneWidth(line[i].chr)
if dx > 0 {
if x <= col {
x = col
break
}
continue
}
if x < col {
x = prevCol
break
}
}
v.moveCursor(x-ox, y-oy, writeMode)
}
func (v *View) moveCursor(dx, dy int, writeMode bool) {
maxX, maxY := v.Size()
cx, cy := v.cx+dx, v.cy+dy
x, y := v.ox+cx, v.oy+cy
var curLineWidth, prevLineWidth int
// get the width of the current line
curLineWidth = maxInt
if v.Wrap {
curLineWidth = maxX - 1
}
if !writeMode {
curLineWidth = 0
if y >= 0 && y < len(v.viewLines) {
|