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authorSimon Ser <contact@emersion.fr>2019-04-27 15:09:59 +0000
committerDrew DeVault <sir@cmpwn.com>2019-04-27 11:42:12 -0400
commit2159eb876e7e04e81f65e64b1d742ad832890289 (patch)
tree672eabb782e3a0647a6607cd0c973834021747fc
parente72574c308c04cb30af95f5c88983e0cab798fea (diff)
widgets/spinner: fix Spinner.frame race
It's accessed by the goroutine which increments it and the goroutine that draws the widget at the same time. Use atomic instead. Write at 0x00c00000ebc0 by goroutine 7: git.sr.ht/~sircmpwn/aerc2/widgets.(*Spinner).Start.func1() /home/simon/src/aerc2/widgets/spinner.go:50 +0x169 Previous read at 0x00c00000ebc0 by main goroutine: [failed to restore the stack] Goroutine 7 (running) created at: git.sr.ht/~sircmpwn/aerc2/widgets.(*Spinner).Start() /home/simon/src/aerc2/widgets/spinner.go:44 +0x8b git.sr.ht/~sircmpwn/aerc2/widgets.NewDirectoryList() /home/simon/src/aerc2/widgets/dirlist.go:37 +0x286 git.sr.ht/~sircmpwn/aerc2/widgets.NewAccountView() /home/simon/src/aerc2/widgets/account.go:50 +0x5ca git.sr.ht/~sircmpwn/aerc2/widgets.NewAerc() /home/simon/src/aerc2/widgets/aerc.go:60 +0x800 main.main() /home/simon/src/aerc2/aerc.go:65 +0x33e
-rw-r--r--widgets/spinner.go27
1 files changed, 15 insertions, 12 deletions
diff --git a/widgets/spinner.go b/widgets/spinner.go
index bafc712..0ab3e13 100644
--- a/widgets/spinner.go
+++ b/widgets/spinner.go
@@ -1,6 +1,7 @@
package widgets
import (
+ "sync/atomic"
"time"
"github.com/gdamore/tcell"
@@ -22,14 +23,14 @@ var (
)
type Spinner struct {
- frame int
+ frame int64 // access via atomic
onInvalidate func(d ui.Drawable)
- stop chan interface{}
+ stop chan struct{}
}
func NewSpinner() *Spinner {
spinner := Spinner{
- stop: make(chan interface{}),
+ stop: make(chan struct{}),
frame: -1,
}
return &spinner
@@ -40,17 +41,17 @@ func (s *Spinner) Start() {
return
}
- s.frame = 0
+ atomic.StoreInt64(&s.frame, 0)
+
go func() {
for {
select {
case <-s.stop:
+ atomic.StoreInt64(&s.frame, -1)
+ s.stop <- struct{}{}
return
case <-time.After(200 * time.Millisecond):
- s.frame++
- if s.frame >= len(frames) {
- s.frame = 0
- }
+ atomic.AddInt64(&s.frame, 1)
s.Invalidate()
}
}
@@ -62,13 +63,13 @@ func (s *Spinner) Stop() {
return
}
- s.stop <- nil
- s.frame = -1
+ s.stop <- struct{}{}
+ <-s.stop
s.Invalidate()
}
func (s *Spinner) IsRunning() bool {
- return s.frame != -1
+ return atomic.LoadInt64(&s.frame) != -1
}
func (s *Spinner) Draw(ctx *ui.Context) {
@@ -76,9 +77,11 @@ func (s *Spinner) Draw(ctx *ui.Context) {
s.Start()
}
+ cur := int(atomic.LoadInt64(&s.frame) % int64(len(frames)))
+
ctx.Fill(0, 0, ctx.Width(), ctx.Height(), ' ', tcell.StyleDefault)
col := ctx.Width()/2 - len(frames[0])/2 + 1
- ctx.Printf(col, 0, tcell.StyleDefault, "%s", frames[s.frame])
+ ctx.Printf(col, 0, tcell.StyleDefault, "%s", frames[cur])
}
func (s *Spinner) OnInvalidate(onInvalidate func(d ui.Drawable)) {