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listing.go
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listing.go
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package edit
import (
"container/list"
"fmt"
"strings"
"unicode/utf8"
"github.com/u-root/u-root/cmds/core/elvish/edit/eddefs"
"github.com/u-root/u-root/cmds/core/elvish/edit/ui"
"github.com/u-root/u-root/cmds/core/elvish/eval"
"github.com/u-root/u-root/cmds/core/elvish/eval/vars"
"github.com/u-root/u-root/cmds/core/elvish/util"
)
// listingMode implements a mode that supports listing, selecting and filtering
// entries.
type listingMode struct {
commonBinding eddefs.BindingMap
listingState
}
type listingState struct {
binding eddefs.BindingMap
provider eddefs.ListingProvider
selected int
filter string
pagesize int
headerWidth int
}
func init() { atEditorInit(initListing) }
func initListing(ed *editor, ns eval.Ns) {
l := &listingMode{commonBinding: emptyBindingMap}
ed.listing = l
subns := eval.Ns{
"binding": vars.FromPtr(&l.commonBinding),
}
subns.AddBuiltinFns("edit:listing:", map[string]interface{}{
"up": func() { l.up(false) },
"up-cycle": func() { l.up(true) },
"page-up": func() { l.pageUp() },
"down": func() { l.down(false) },
"down-cycle": func() { l.down(true) },
"page-down": func() { l.pageDown() },
"backspace": func() { l.backspace() },
"accept": func() { l.accept(ed) },
"accept-close": func() {
l.accept(ed)
ed.SetModeInsert()
},
"default": func() { l.defaultBinding(ed) },
})
ns.AddNs("listing", subns)
}
type placeholderer interface {
Placeholder() string
}
func (l *listingMode) Teardown() {
l.listingState = listingState{}
if p, ok := l.provider.(teardowner); ok {
p.Teardown()
}
}
type teardowner interface {
Teardown()
}
func (l *listingMode) Binding(k ui.Key) eval.Callable {
specificBindings := l.binding
listingBindings := l.commonBinding
// mode-specific binding -> listing binding ->
// mode-specific default -> listing default
switch {
case specificBindings.HasKey(k):
return specificBindings.GetKey(k)
case listingBindings.HasKey(k):
return listingBindings.GetKey(k)
case specificBindings.HasKey(ui.Default):
return specificBindings.GetKey(ui.Default)
case listingBindings.HasKey(ui.Default):
return listingBindings.GetKey(ui.Default)
default:
return nil
}
}
func newListing(b eddefs.BindingMap, p eddefs.ListingProvider) *listingState {
l := &listingState{}
l.setup(b, p)
return l
}
func (l *listingState) setup(b eddefs.BindingMap, p eddefs.ListingProvider) {
*l = listingState{b, p, 0, "", 0, 0}
l.refresh()
for i := 0; i < p.Len(); i++ {
header, _ := p.Show(i)
width := util.Wcswidth(header)
if l.headerWidth < width {
l.headerWidth = width
}
}
}
func (l *listingState) ModeLine() ui.Renderer {
return ui.NewModeLineRenderer(l.provider.ModeTitle(l.selected), l.filter)
}
func (l *listingState) CursorOnModeLine() bool {
if c, ok := l.provider.(cursorOnModeLiner); ok {
return c.CursorOnModeLine()
}
return false
}
func (l *listingState) List(maxHeight int) ui.Renderer {
n := l.provider.Len()
if n == 0 {
var ph string
if pher, ok := l.provider.(placeholderer); ok {
ph = pher.Placeholder()
} else {
ph = "(no result)"
}
return placeholderRenderer(ph)
}
// Collect the entries to show. We start from the selected entry and extend
// in both directions alternatingly. The entries are split into lines and
// then collected in a list.
low := l.selected
if low == -1 {
low = 0
}
high := low
height := 0
var listOfLines list.List
getEntry := func(i int) []ui.Styled {
header, content := l.provider.Show(i)
lines := strings.Split(content.Text, "\n")
styles := content.Styles
if i == l.selected {
styles = append(styles, styleForSelected...)
}
styleds := make([]ui.Styled, len(lines))
for i, line := range lines {
if l.headerWidth > 0 {
if i == 0 {
line = fmt.Sprintf("%*s %s", l.headerWidth, header, line)
} else {
line = fmt.Sprintf("%*s %s", l.headerWidth, "", line)
}
}
styleds[i] = ui.Styled{line, styles}
}
return styleds
}
// We start by extending high, so that the first entry to include is
// l.selected.
extendLow := false
lastShownIncomplete := false
for height < maxHeight && !(low == 0 && high == n) {
var i int
if (extendLow && low > 0) || high == n {
low--
entry := getEntry(low)
// Prepend at most the last (height - maxHeight) lines.
for i = len(entry) - 1; i >= 0 && height < maxHeight; i-- {
listOfLines.PushFront(entry[i])
height++
}
if i >= 0 {
lastShownIncomplete = true
}
} else {
entry := getEntry(high)
// Append at most the first (height - maxHeight) lines.
for i = 0; i < len(entry) && height < maxHeight; i++ {
listOfLines.PushBack(entry[i])
height++
}
if i < len(entry) {
lastShownIncomplete = true
}
high++
}
extendLow = !extendLow
}
l.pagesize = high - low
// Convert the List to a slice.
lines := make([]ui.Styled, 0, listOfLines.Len())
for p := listOfLines.Front(); p != nil; p = p.Next() {
lines = append(lines, p.Value.(ui.Styled))
}
ls := listingRenderer{lines}
if low > 0 || high < n || lastShownIncomplete {
// Need scrollbar
return listingWithScrollBarRenderer{ls, n, low, high, height}
}
return ls
}
func writeHorizontalScrollbar(b *ui.Buffer, n, low, high, width int) {
slow, shigh := findScrollInterval(n, low, high, width)
for i := 0; i < width; i++ {
if slow <= i && i < shigh {
b.Write(' ', styleForScrollBarThumb.String())
} else {
b.Write('━', styleForScrollBarArea.String())
}
}
}
func renderScrollbar(n, low, high, height int) *ui.Buffer {
slow, shigh := findScrollInterval(n, low, high, height)
// Logger.Printf("low = %d, high = %d, n = %d, slow = %d, shigh = %d", low, high, n, slow, shigh)
b := ui.NewBuffer(1)
for i := 0; i < height; i++ {
if i > 0 {
b.Newline()
}
if slow <= i && i < shigh {
b.Write(' ', styleForScrollBarThumb.String())
} else {
b.Write('│', styleForScrollBarArea.String())
}
}
return b
}
func findScrollInterval(n, low, high, height int) (int, int) {
f := func(i int) int {
return int(float64(i)/float64(n)*float64(height) + 0.5)
}
scrollLow, scrollHigh := f(low), f(high)
if scrollLow == scrollHigh {
if scrollHigh == high {
scrollLow--
} else {
scrollHigh++
}
}
return scrollLow, scrollHigh
}
func (l *listingState) changeFilter(newfilter string) {
l.filter = newfilter
l.refresh()
}
func (l *listingState) refresh() {
l.selected = l.provider.Filter(l.filter)
}
func (l *listingState) backspace() bool {
_, size := utf8.DecodeLastRuneInString(l.filter)
if size > 0 {
l.changeFilter(l.filter[:len(l.filter)-size])
return true
}
return false
}
func (l *listingState) up(cycle bool) {
n := l.provider.Len()
if n == 0 {
return
}
l.selected--
if l.selected == -1 {
if cycle {
l.selected += n
} else {
l.selected++
}
}
}
func (l *listingState) pageUp() {
n := l.provider.Len()
if n == 0 {
return
}
l.selected -= l.pagesize
if l.selected < 0 {
l.selected = 0
}
}
func (l *listingState) down(cycle bool) {
n := l.provider.Len()
if n == 0 {
return
}
l.selected++
if l.selected == n {
if cycle {
l.selected -= n
} else {
l.selected--
}
}
}
func (l *listingState) pageDown() {
n := l.provider.Len()
if n == 0 {
return
}
l.selected += l.pagesize
if l.selected >= n {
l.selected = n - 1
}
}
func (l *listingState) accept(ed *editor) {
if l.selected >= 0 {
l.provider.Accept(l.selected, ed)
}
}
func (l *listingState) defaultBinding(ed *editor) {
k := ed.LastKey()
if likeChar(k) {
// Append to filter
l.changeFilter(l.filter + string(k.Rune))
if aa, ok := l.provider.(autoAccepter); ok {
if aa.AutoAccept() {
l.accept(ed)
}
}
} else {
ed.SetModeInsert()
ed.SetAction(reprocessKey)
}
}
type autoAccepter interface {
AutoAccept() bool
}