eth/downloader: fix cancel channel double close

4f0d88cb · Péter Szilágyi · 7d71a75d · 4f0d88cb
Commit 4f0d88cb authored May 15, 2015 by Péter Szilágyi
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Showing with 8 additions and 3 deletions

downloader.go eth/downloader/downloader.go +8 -3

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--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -212,9 +212,14 @@ func (d *Downloader) Cancel() bool {
 		return false
 	}
 	// Close the current cancel channel
-	d.cancelLock.RLock()
-	close(d.cancelCh)
-	d.cancelLock.RUnlock()
+	d.cancelLock.Lock()
+	select {
+	case <-d.cancelCh:
+		// Channel was already closed
+	default:
+		close(d.cancelCh)
+	}
+	d.cancelLock.Unlock()

 	// reset the queue
 	d.queue.Reset()