init: pristine aerc 0.20.0 source

app/spinner.go

@@ -0,0 +1,85 @@
+package app
+
+import (
+	"strings"
+	"sync/atomic"
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/config"
+	"git.sr.ht/~rjarry/aerc/lib/log"
+	"git.sr.ht/~rjarry/aerc/lib/ui"
+	"git.sr.ht/~rockorager/vaxis"
+)
+
+type Spinner struct {
+	frame    int64 // access via atomic
+	frames   []string
+	interval time.Duration
+	stop     chan struct{}
+	style    vaxis.Style
+}
+
+func NewSpinner(uiConf *config.UIConfig) *Spinner {
+	spinner := Spinner{
+		stop:     make(chan struct{}),
+		frame:    -1,
+		interval: uiConf.SpinnerInterval,
+		frames:   strings.Split(uiConf.Spinner, uiConf.SpinnerDelimiter),
+		style:    uiConf.GetStyle(config.STYLE_SPINNER),
+	}
+	return &spinner
+}
+
+func (s *Spinner) Start() {
+	if s.IsRunning() {
+		return
+	}
+
+	atomic.StoreInt64(&s.frame, 0)
+
+	go func() {
+		defer log.PanicHandler()
+
+		for {
+			select {
+			case <-s.stop:
+				atomic.StoreInt64(&s.frame, -1)
+				s.stop <- struct{}{}
+				return
+			case <-time.After(s.interval):
+				atomic.AddInt64(&s.frame, 1)
+				ui.Invalidate()
+			}
+		}
+	}()
+}
+
+func (s *Spinner) Stop() {
+	if !s.IsRunning() {
+		return
+	}
+
+	s.stop <- struct{}{}
+	<-s.stop
+	s.Invalidate()
+}
+
+func (s *Spinner) IsRunning() bool {
+	return atomic.LoadInt64(&s.frame) != -1
+}
+
+func (s *Spinner) Draw(ctx *ui.Context) {
+	if !s.IsRunning() {
+		s.Start()
+	}
+
+	cur := int(atomic.LoadInt64(&s.frame) % int64(len(s.frames)))
+
+	ctx.Fill(0, 0, ctx.Width(), ctx.Height(), ' ', s.style)
+	col := ctx.Width()/2 - len(s.frames[0])/2 + 1
+	ctx.Printf(col, 0, s.style, "%s", s.frames[cur])
+}
+
+func (s *Spinner) Invalidate() {
+	ui.Invalidate()
+}