From 04a3c45f602fb391d650940f5bba18f1e3788366 Mon Sep 17 00:00:00 2001
From: Alessandro Ros <aler9.dev@gmail.com>
Date: Sat, 26 Aug 2023 17:23:54 +0200
Subject: [PATCH] ringbuffer: discard pending data when buffer is closed (#387)

---
 pkg/ringbuffer/ringbuffer.go      |  9 ++++++++
 pkg/ringbuffer/ringbuffer_test.go | 36 +++++++++++++++----------------
 2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/pkg/ringbuffer/ringbuffer.go b/pkg/ringbuffer/ringbuffer.go
index 31f8c90e..364aea31 100644
--- a/pkg/ringbuffer/ringbuffer.go
+++ b/pkg/ringbuffer/ringbuffer.go
@@ -38,7 +38,14 @@ func New(size uint64) (*RingBuffer, error) {
 // Close makes Pull() return false.
 func (r *RingBuffer) Close() {
 	r.mutex.Lock()
+
 	r.closed = true
+
+	// discard pending data to make Pull() exit immediately
+	for i := uint64(0); i < r.size; i++ {
+		r.buffer[i] = nil
+	}
+
 	r.mutex.Unlock()
 	r.cond.Broadcast()
 }
@@ -48,6 +55,7 @@ func (r *RingBuffer) Reset() {
 	for i := uint64(0); i < r.size; i++ {
 		r.buffer[i] = nil
 	}
+
 	r.writeIndex = 0
 	r.readIndex = 0
 	r.closed = false
@@ -64,6 +72,7 @@ func (r *RingBuffer) Push(data interface{}) bool {
 
 	r.buffer[r.writeIndex] = data
 	r.writeIndex = (r.writeIndex + 1) % r.size
+
 	r.mutex.Unlock()
 
 	r.cond.Broadcast()
diff --git a/pkg/ringbuffer/ringbuffer_test.go b/pkg/ringbuffer/ringbuffer_test.go
index 1c20a5f7..ff553096 100644
--- a/pkg/ringbuffer/ringbuffer_test.go
+++ b/pkg/ringbuffer/ringbuffer_test.go
@@ -51,30 +51,28 @@ func TestClose(t *testing.T) {
 	r, err := New(1024)
 	require.NoError(t, err)
 
-	done := make(chan struct{})
-	go func() {
-		defer close(done)
-
-		_, ok := r.Pull()
-		require.Equal(t, true, ok)
-
-		_, ok = r.Pull()
-		require.Equal(t, false, ok)
-	}()
-
 	ok := r.Push([]byte{1, 2, 3, 4})
 	require.Equal(t, true, ok)
 
-	r.Close()
-	<-done
-
-	r.Reset()
-
-	ok = r.Push([]byte{5, 6, 7, 8})
-	require.Equal(t, true, ok)
-
 	_, ok = r.Pull()
 	require.Equal(t, true, ok)
+
+	ok = r.Push([]byte{5, 6, 7, 8})
+	require.Equal(t, true, ok)
+
+	r.Close()
+
+	_, ok = r.Pull()
+	require.Equal(t, false, ok)
+
+	r.Reset()
+
+	ok = r.Push([]byte{9, 10, 11, 12})
+	require.Equal(t, true, ok)
+
+	data, ok := r.Pull()
+	require.Equal(t, true, ok)
+	require.Equal(t, []byte{9, 10, 11, 12}, data)
 }
 
 func TestOverflow(t *testing.T) {