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Export Undo/Redo functions #100

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8eed6f9
Export Undo/Redo functions
FabienJansem Sep 4, 2022
9c40570
Export Undo/Redo functions
FabienJansem Sep 4, 2022
57e183d
Merge branch 'gioui:main' into main
FabienJansem Sep 17, 2022
ebde3ac
Merge branch 'gioui:main' into main
FabienJansem Nov 7, 2022
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58 changes: 35 additions & 23 deletions widget/editor.go
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Original file line number Diff line number Diff line change
Expand Up @@ -111,11 +111,7 @@ type Editor struct {
locale system.Locale

// history contains undo history.
history []modification
// nextHistoryIdx is the index within the history of the next modification. This
// is only not len(history) immediately after undo operations occur. It is framed as the "next" value
// to make the zero value consistent.
nextHistoryIdx int
History *History
}

type offEntry struct {
Expand Down Expand Up @@ -503,9 +499,9 @@ func (e *Editor) command(gtx layout.Context, k key.Event) {
e.caret.start = e.Len()
case "Z":
if k.Modifiers.Contain(key.ModShift) {
e.redo()
e.Redo()
} else {
e.undo()
e.Undo()
}
}
}
Expand Down Expand Up @@ -892,15 +888,18 @@ func (e *Editor) Text() string {
}

// SetText replaces the contents of the editor, clearing any selection first.
// History is cleared before and after replacement
func (e *Editor) SetText(s string) {
e.rr = editBuffer{}
e.caret.start = 0
e.caret.end = 0
e.History = nil // avoid alteration of previous text history
if e.SingleLine {
s = strings.ReplaceAll(s, "\n", " ")
}
e.replace(e.caret.start, e.caret.end, s, true)
e.caret.xoff = 0
e.History = nil // initial text is not a modification
}

func (e *Editor) scrollBounds() image.Rectangle {
Expand Down Expand Up @@ -1274,32 +1273,42 @@ type modification struct {
ReverseContent string
}

// undo applies the modification at e.history[e.historyIdx] and decrements
// e.historyIdx.
func (e *Editor) undo() {
if len(e.history) < 1 || e.nextHistoryIdx == 0 {
// History of modifications may be retrived/restored
type History struct {
// data contains undo/redo history.
data []modification
// nextIdx is the index within the history data of the next modification.
// This is only not len(data) immediately after undo operations occur.
// It is framed as the "next" value to make the zero value consistent.
nextIdx int
}

// Undo applies the modification at e.history.data[e.history.nextIdx]
// and decrements e.history.nextIdx.
func (e *Editor) Undo() {
if e.History == nil || len(e.History.data) < 1 || e.History.nextIdx == 0 {
return
}
mod := e.history[e.nextHistoryIdx-1]
mod := e.History.data[e.History.nextIdx-1]
replaceEnd := mod.StartRune + utf8.RuneCountInString(mod.ApplyContent)
e.replace(mod.StartRune, replaceEnd, mod.ReverseContent, false)
caretEnd := mod.StartRune + utf8.RuneCountInString(mod.ReverseContent)
e.SetCaret(caretEnd, mod.StartRune)
e.nextHistoryIdx--
e.History.nextIdx--
}

// redo applies the modification at e.history[e.historyIdx] and increments
// e.historyIdx.
func (e *Editor) redo() {
if len(e.history) < 1 || e.nextHistoryIdx == len(e.history) {
// Redo applies the modification at e.history.data[e.history.nextIdx]
// and increments e.history.nextIdx.
func (e *Editor) Redo() {
if e.History == nil || len(e.History.data) < 1 || e.History.nextIdx == len(e.History.data) {
return
}
mod := e.history[e.nextHistoryIdx]
mod := e.History.data[e.History.nextIdx]
end := mod.StartRune + utf8.RuneCountInString(mod.ReverseContent)
e.replace(mod.StartRune, end, mod.ApplyContent, false)
caretEnd := mod.StartRune + utf8.RuneCountInString(mod.ApplyContent)
e.SetCaret(caretEnd, mod.StartRune)
e.nextHistoryIdx++
e.History.nextIdx++
}

// replace the text between start and end with s. Indices are in runes.
Expand Down Expand Up @@ -1339,15 +1348,18 @@ func (e *Editor) replace(start, end int, s string, addHistory bool) int {
ru, _, _ := e.rr.ReadRune()
deleted = append(deleted, ru)
}
if e.nextHistoryIdx < len(e.history) {
e.history = e.history[:e.nextHistoryIdx]
if e.History == nil {
e.History = &History{}
}
if e.History.nextIdx < len(e.History.data) {
e.History.data = e.History.data[:e.History.nextIdx]
}
e.history = append(e.history, modification{
e.History.data = append(e.History.data, modification{
StartRune: startPos.runes,
ApplyContent: s,
ReverseContent: string(deleted),
})
e.nextHistoryIdx++
e.History.nextIdx++
}

e.rr.deleteRunes(startOff, replaceSize)
Expand Down
63 changes: 58 additions & 5 deletions widget/editor_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -47,10 +47,10 @@ func TestEditorHistory(t *testing.T) {
e.Insert("")
assertContents(t, e, "", 0, 0)
// Ensure that undoing the overwrite succeeds.
e.undo()
e.Undo()
assertContents(t, e, "안П你 hello 안П你", 13, 0)
// Ensure that redoing the overwrite succeeds.
e.redo()
e.Redo()
assertContents(t, e, "", 0, 0)
// Insert some smaller text.
e.Insert("안П你 hello")
Expand All @@ -64,9 +64,9 @@ func TestEditorHistory(t *testing.T) {
e.Insert("П")
assertContents(t, e, "안ПeПlo", 4, 4)
// Ensure both operations undo successfully.
e.undo()
e.Undo()
assertContents(t, e, "안Пello", 4, 3)
e.undo()
e.Undo()
assertContents(t, e, "안П你 hello", 5, 1)
// Make a new modification.
e.Insert("Something New")
Expand All @@ -75,10 +75,63 @@ func TestEditorHistory(t *testing.T) {
// This redo() call should do nothing.
text := e.Text()
start, end := e.Selection()
e.redo()
e.Redo()
assertContents(t, e, text, start, end)
}

// TestEditorHistoryExpose ensures that History and SetHistory behave correctly.
func TestEditorHistoryExpose(t *testing.T) {
e := new(Editor)
// Insert some text and do modifications.
e.Insert("안П你 hello")
e.SetCaret(1, 5)
e.Insert("П")
e.SetCaret(3, 4)
e.Insert("П")
// Save text and history
savedText := e.Text()
savedHistory := e.History
// Clear history
e.History = nil
// Ensure no more Undo/Redo available
e.Undo()
assertContents(t, e, "안ПeПlo", 4, 4)
e.Redo()
assertContents(t, e, "안ПeПlo", 4, 4)
// restore history
e.History = savedHistory
// Ensure all Undos are back
e.Undo()
assertContents(t, e, "안Пello", 4, 3)
e.Undo()
assertContents(t, e, "안П你 hello", 5, 1)
e.Undo()
assertContents(t, e, "", 0, 0)
// Ensure Redo also works
e.Redo()
assertContents(t, e, "안П你 hello", 9, 0)
e.Redo()
assertContents(t, e, "안Пello", 2, 1)
e.Redo()
assertContents(t, e, "안ПeПlo", 4, 3)
// Init a new text
e.SetText("New text")
// Ensure history has been cleared
e.Undo()
assertContents(t, e, "New text", 0, 0)
// Put back previous text and history
e.SetText(savedText)
assertContents(t, e, "안ПeПlo", 0, 0)
e.History = savedHistory
// Ensure all Undos are back
e.Undo()
assertContents(t, e, "안Пello", 4, 3)
e.Undo()
assertContents(t, e, "안П你 hello", 5, 1)
e.Undo()
assertContents(t, e, "", 0, 0)
}

func assertContents(t *testing.T, e *Editor, contents string, selectionStart, selectionEnd int) {
t.Helper()
actualContents := e.Text()
Expand Down