editor: reduce input latency in large documents

editor.go

@@ -370,6 +370,9 @@ func (e *Editor) GetReader() io.ReadSeeker {
 // before populate the internal text buffer.
 func (e *Editor) SetText(s string) {
 	e.initBuffer()
+	e.resetIME()
+	clear(e.autoInsertions)
+	e.lastInput = nil
 
 	indent, _, size := GuessIndentation(s)
 	e.text.SoftTab = indent == Spaces
@@ -378,12 +381,17 @@ func (e *Editor) SetText(s string) {
 	e.lineEnding = DetectLineEnding(s)
 
 	e.text.SetText(StripLineEnding(s))
-	e.ime.start = 0
-	e.ime.end = 0
 	// Reset xoff and move the caret to the beginning.
 	e.SetCaret(0, 0)
 }
 
+func (e *Editor) resetIME() {
+	if e.ime.isComposing {
+		e.buffer.UnGroupOp()
+	}
+	e.ime.imeState = imeState{}
+}
+
 // CaretPos returns the line & column numbers of the caret.
 func (e *Editor) CaretPos() (line, col int) {
 	e.initBuffer()
@@ -576,6 +584,18 @@ func (e *Editor) replace(start, end int, s string) int {
 
 	sc := e.text.Replace(start, end, s)
 	newEnd := start + sc
+	if len(e.autoInsertions) > 0 && (start != end || sc != 0) {
+		updated := make(map[int]rune, len(e.autoInsertions))
+		for pos, r := range e.autoInsertions {
+			switch {
+			case pos < start:
+				updated[pos] = r
+			case pos >= end:
+				updated[pos+newEnd-end] = r
+			}
+		}
+		e.autoInsertions = updated
+	}
 	adjust := func(pos int) int {
 		switch {
 		case newEnd < pos && pos <= end:

event.go

@@ -41,11 +41,10 @@ func (e *Editor) processEvents(gtx layout.Context) (ev EditorEvent, ok bool) {
 			}
 		}
 
-		switch ev.(type) {
-		case ChangeEvent:
+		if isChangeEvent(ev) {
 			e.wordHighlighter.MarkActive(false)
 			e.updateCompletor()
-		case SelectEvent:
+		} else if _, ok := ev.(SelectEvent); ok {
 			e.updateCompletor()
 		}
 	}()
@@ -215,6 +214,11 @@ func (e *Editor) processKey(gtx layout.Context) (EditorEvent, bool) {
 	}
 
 	if evt := e.processCommands(gtx); evt != nil {
+		// The command already reported this change; consume the buffer flag so
+		// the next Update call does not report it again.
+		if isChangeEvent(evt) {
+			e.text.Changed()
+		}
 		return evt, true
 	}
 
@@ -225,6 +229,15 @@ func (e *Editor) processKey(gtx layout.Context) (EditorEvent, bool) {
 	return nil, false
 }
 
+func isChangeEvent(evt EditorEvent) bool {
+	switch evt.(type) {
+	case ChangeEvent, *ChangeEvent:
+		return true
+	default:
+		return false
+	}
+}
+
 func (e *Editor) processEditEvents(gtx layout.Context) EditorEvent {
 	filters := []event.Filter{
 		key.FocusFilter{Target: e},
@@ -241,8 +254,7 @@ func (e *Editor) processEditEvents(gtx layout.Context) EditorEvent {
 
 		switch ke := evt.(type) {
 		case key.FocusEvent:
-			// Reset IME state.
-			e.ime.imeState = imeState{}
+			e.resetIME()
 			if ke.Focus && e.mode != ModeReadOnly {
 				gtx.Execute(key.SoftKeyboardCmd{Show: true})
 			}
@@ -481,9 +493,6 @@ func (e *Editor) onTextInput(ke key.EditEvent) {
 			e.text.MoveCaret(-1, -1)
 			start, _ := e.text.Selection() // start and end should be the same
 			e.autoInsertions[start] = counterpart
-		} else {
-			// If only the opening char was inserted, ensure it's not tracked
-			delete(e.autoInsertions, ke.Range.Start)
 		}
 
 	} else if counterpart > 0 {
@@ -500,7 +509,6 @@ func (e *Editor) onTextInput(ke key.EditEvent) {
 			e.replace(ke.Range.Start, ke.Range.End, ke.Text)
 		}
 	} else {
-		delete(e.autoInsertions, ke.Range.Start)
 		e.replace(ke.Range.Start, ke.Range.End, ke.Text)
 	}
 

event_test.go

@@ -1,14 +1,214 @@
 package gvcode
 
 import (
+	"image"
+	"strings"
 	"testing"
 
+	"gioui.org/io/input"
+	"gioui.org/io/key"
 	"gioui.org/layout"
+	"gioui.org/op"
 	"gioui.org/text"
 	"gioui.org/unit"
 	"github.com/oligo/gvcode/textview"
 )
 
+func BenchmarkDeleteBackwardLargeDocument(b *testing.B) {
+	doc := strings.Repeat("func main() { println(\"hello\") }\n", 5000)
+	editor := &Editor{}
+	editor.WithOptions(WithTextSize(unit.Sp(14)))
+	editor.SetText(doc)
+	gtx := layout.Context{Constraints: layout.Exact(image.Pt(1200, 800))}
+	editor.text.Layout(gtx, text.NewShaper())
+	editor.SetCaret(editor.Len(), editor.Len())
+
+	b.ResetTimer()
+	for range b.N {
+		editor.Delete(-1)
+	}
+}
+
+func BenchmarkTextInputLargeDocument(b *testing.B) {
+	doc := strings.Repeat("func main() { println(\"hello\") }\n", 5000)
+	editor := &Editor{}
+	editor.WithOptions(WithTextSize(unit.Sp(14)))
+	editor.SetText(doc)
+	textGtx := layout.Context{Constraints: layout.Exact(image.Pt(1200, 800))}
+	shaper := text.NewShaper()
+	editor.text.Layout(textGtx, shaper)
+	editor.SetCaret(editor.Len(), editor.Len())
+
+	router := new(input.Router)
+	gtx := layout.Context{Ops: new(op.Ops), Source: router.Source()}
+	editor.Update(gtx)
+	router.Frame(new(op.Ops))
+	router.Source().Execute(key.FocusCmd{Tag: editor})
+	for {
+		if _, ok := editor.Update(gtx); !ok {
+			break
+		}
+	}
+
+	b.ResetTimer()
+	for range b.N {
+		b.StopTimer()
+		pos := editor.Len()
+		router.Queue(key.EditEvent{Range: key.Range{Start: pos, End: pos}, Text: "a"})
+		b.StartTimer()
+		evt, ok := editor.Update(gtx)
+		b.StopTimer()
+		if !ok || !isChangeEvent(evt) {
+			b.Fatalf("Update() = (%T, %v), want ChangeEvent", evt, ok)
+		}
+
+		for {
+			if _, ok := editor.Update(gtx); !ok {
+				break
+			}
+		}
+		if _, ok := editor.undo(); !ok {
+			b.Fatal("undo failed")
+		}
+		editor.text.Changed()
+		editor.text.Layout(textGtx, shaper)
+	}
+}
+
+func TestDeleteBackwardEmitsOneChangeEvent(t *testing.T) {
+	editor := &Editor{}
+	editor.SetText("abc")
+	editor.SetCaret(editor.Len(), editor.Len())
+
+	router := new(input.Router)
+	gtx := layout.Context{Ops: new(op.Ops), Source: router.Source()}
+	editor.Update(gtx)
+	router.Frame(new(op.Ops))
+
+	router.Source().Execute(key.FocusCmd{Tag: editor})
+	router.Queue(key.Event{Name: key.NameDeleteBackward, State: key.Press})
+
+	gtx.Source = router.Source()
+	changes := 0
+	for {
+		evt, ok := editor.Update(gtx)
+		if !ok {
+			break
+		}
+		if _, ok := evt.(ChangeEvent); ok {
+			changes++
+		}
+	}
+
+	if changes != 1 {
+		t.Fatalf("DeleteBackward emitted %d ChangeEvents, want 1", changes)
+	}
+	if got := editor.Len(); got != 2 {
+		t.Fatalf("DeleteBackward left %d runes, want 2", got)
+	}
+}
+
+func TestIsChangeEventAcceptsValueAndPointer(t *testing.T) {
+	if !isChangeEvent(ChangeEvent{}) {
+		t.Fatal("value ChangeEvent was not recognized")
+	}
+	if !isChangeEvent(&ChangeEvent{}) {
+		t.Fatal("pointer ChangeEvent was not recognized")
+	}
+	if isChangeEvent(SelectEvent{}) {
+		t.Fatal("SelectEvent was recognized as a ChangeEvent")
+	}
+}
+
+func TestEditEventsEmitOneChangeEventPerFrame(t *testing.T) {
+	editor := &Editor{}
+	editor.SetText("")
+
+	router := new(input.Router)
+	gtx := layout.Context{Ops: new(op.Ops), Source: router.Source()}
+	editor.Update(gtx)
+	router.Frame(new(op.Ops))
+
+	router.Source().Execute(key.FocusCmd{Tag: editor})
+	router.Queue(
+		key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "a"},
+		key.EditEvent{Range: key.Range{Start: 1, End: 1}, Text: "b"},
+	)
+
+	gtx.Source = router.Source()
+	changes := 0
+	for {
+		evt, ok := editor.Update(gtx)
+		if !ok {
+			break
+		}
+		if _, ok := evt.(ChangeEvent); ok {
+			changes++
+		}
+	}
+
+	if changes != 1 {
+		t.Fatalf("two EditEvents emitted %d ChangeEvents, want 1", changes)
+	}
+	if got := editor.Text(); got != "ab" {
+		t.Fatalf("text = %q, want %q", got, "ab")
+	}
+}
+
+func TestResetIMEClosesUndoGroup(t *testing.T) {
+	editor := &Editor{}
+	editor.SetText("")
+	editor.ime.isComposing = true
+	editor.buffer.GroupOp()
+	editor.replace(0, 0, "中")
+
+	editor.resetIME()
+	editor.replace(1, 1, " ")
+
+	if _, ok := editor.undo(); !ok {
+		t.Fatal("undo failed")
+	}
+	if got := editor.Text(); got != "中" {
+		t.Fatalf("undo after IME reset left %q, want %q", got, "中")
+	}
+}
+
+func TestAutoInsertionTracksEditsBeforeClosingRune(t *testing.T) {
+	editor := &Editor{}
+	editor.WithOptions(WithTextSize(unit.Sp(14)))
+	editor.SetText("")
+	editor.text.Layout(layout.Context{Constraints: layout.Exact(image.Pt(800, 600))}, text.NewShaper())
+
+	editor.onTextInput(key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "("})
+	editor.onTextInput(key.EditEvent{Range: key.Range{Start: 1, End: 1}, Text: "x"})
+	editor.onTextInput(key.EditEvent{Range: key.Range{Start: 2, End: 2}, Text: ")"})
+
+	if got := editor.Text(); got != "(x)" {
+		t.Fatalf("text = %q, want %q", got, "(x)")
+	}
+	start, end := editor.Selection()
+	if start != 3 || end != 3 {
+		t.Fatalf("selection = (%d, %d), want (3, 3)", start, end)
+	}
+}
+
+func TestAutoInsertionTracksPairAfterEarlierEdit(t *testing.T) {
+	editor := &Editor{}
+	editor.WithOptions(WithTextSize(unit.Sp(14)))
+	editor.SetText("")
+	editor.text.Layout(layout.Context{Constraints: layout.Exact(image.Pt(800, 600))}, text.NewShaper())
+
+	editor.onTextInput(key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "("})
+	editor.onTextInput(key.EditEvent{Range: key.Range{Start: 0, End: 0}, Text: "x"})
+	if deleted := editor.Delete(-1); deleted != 2 {
+		t.Fatalf("deleted runes = %d, want 2", deleted)
+	}
+
+	if got := editor.Text(); got != "x" {
+		t.Fatalf("text = %q, want %q", got, "x")
+	}
+}
+
 func TestOnDeleteBackward_Indentation(t *testing.T) {
 	setup := func(input string, cursorPos, tabWidth int) *Editor {
 		vw := textview.NewTextView()