X-Git-Url: https://git.korewanetadesu.com/?p=go-signalcontext.git;a=blobdiff_plain;f=context.go;fp=context.go;h=36814173c766818da86475eb314b84f450eaf99d;hp=1bd24d317d105d42a87fa8e043ae677540631e92;hb=6d43b73af18d23a4cab88dccf8d93a8eb423d2ed;hpb=3ee8799a0bb3e7ba3628b83832fb14462241643d

diff --git a/context.go b/context.go
index 1bd24d3..3681417 100644
--- a/context.go
+++ b/context.go
@@ -28,14 +28,14 @@ type Context struct {
 func UntilSignal(parent context.Context, sig ...os.Signal) *Context {
 	ctx := new(Context)
 	ctx.parent = parent
-	ctx.done = make(chan struct{})
 
 	if err := parent.Err(); err != nil {
-		close(ctx.done)
+		ctx.done = alreadyclosed
 		ctx.err = err
 		return ctx
 	}
 
+	ctx.done = make(chan struct{})
 	ctx.c = make(chan os.Signal, 1)
 	signal.Notify(ctx.c, sig...)
 	go ctx.wait(sig...)
@@ -103,3 +103,11 @@ func (s *Context) Err() error {
 	s.m.Unlock()
 	return err
 }
+
+// Reuse the same channel for all contexts which begin life already
+// completed.
+var alreadyclosed = make(chan struct{})
+
+func init() {
+	close(alreadyclosed)
+}