fix: don't shrink ring-buffer when it's empty

Fixes panjf2000#226
job2wd · Jul 18, 2021 · 545baa9 · 545baa9
1 parent 5548133
commit 545baa9
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Showing 2 changed files with 34 additions and 34 deletions.
diff --git a/ringbuffer/ring_buffer.go b/ringbuffer/ring_buffer.go
@@ -26,7 +26,7 @@ import (
 	"github.com/panjf2000/gnet/pool/bytebuffer"
 )
 
-const initSize = 1 << 12 // 4096 bytes for the first-time allocation on ring-buffer.
+const defaultBufferSize = 1 << 12 // 4096 bytes for the first-time allocation on ring-buffer.
 
 // ErrIsEmpty will be returned when trying to read a empty ring-buffer.
 var ErrIsEmpty = errors.New("ring-buffer is empty")
@@ -374,19 +374,19 @@ func (r *RingBuffer) Reset() {
 	r.r, r.w = 0, 0
 
 	// Shrink the internal buffer for saving memory.
-	newCap := r.size >> 1
-	newBuf := make([]byte, newCap)
-	r.buf = newBuf
-	r.size = newCap
-	r.mask = newCap - 1
+	// newCap := r.size >> 1
+	// newBuf := make([]byte, newCap)
+	// r.buf = newBuf
+	// r.size = newCap
+	// r.mask = newCap - 1
 }
 
-func (r *RingBuffer) malloc(cap int) {
+func (r *RingBuffer) malloc(n int) {
 	var newCap int
-	if r.size == 0 && cap < initSize {
-		newCap = initSize
+	if r.size == 0 && n < defaultBufferSize {
+		newCap = defaultBufferSize
 	} else {
-		newCap = internal.CeilToPowerOfTwo(r.size + cap)
+		newCap = internal.CeilToPowerOfTwo(r.size + n)
 	}
 	newBuf := make([]byte, newCap)
 	oldLen := r.Length()

diff --git a/ringbuffer/ring_buffer_test.go b/ringbuffer/ring_buffer_test.go
@@ -208,10 +208,10 @@ func TestZeroRingBuffer(t *testing.T) {
 	}
 	buf := []byte(strings.Repeat("1234", 12))
 	_, _ = rb.Write(buf)
-	if !(rb.Len() == initSize && rb.Cap() == initSize) {
+	if !(rb.Len() == defaultBufferSize && rb.Cap() == defaultBufferSize) {
 		t.Fatalf("expect rb.Len()=64 and rb.Cap=64, but got rb.Len()=%d and rb.Cap()=%d", rb.Len(), rb.Cap())
 	}
-	if !(rb.r == 0 && rb.w == 48 && rb.size == initSize && rb.mask == initSize-1) {
+	if !(rb.r == 0 && rb.w == 48 && rb.size == defaultBufferSize && rb.mask == defaultBufferSize-1) {
 		t.Fatalf("expect rb.r=0, rb.w=48, rb.size=64, rb.mask=63, but got rb.r=%d, rb.w=%d, rb.size=%d, rb.mask=%d",
 			rb.r, rb.w, rb.size, rb.mask)
 	}
@@ -276,7 +276,7 @@ func TestRingBuffer_Read(t *testing.T) {
 	if rb.Length() != 0 {
 		t.Fatalf("expect len 0 bytes but got %d. r.w=%d, r.r=%d", rb.Length(), rb.w, rb.r)
 	}
-	if rb.Free() != 32 {
+	if rb.Free() != 64 {
 		t.Fatalf("expect free 64 bytes but got %d. r.w=%d, r.r=%d", rb.Free(), rb.w, rb.r)
 	}
 	if rb.r != 0 {
@@ -296,7 +296,7 @@ func TestRingBuffer_Read(t *testing.T) {
 	if rb.Length() != 0 {
 		t.Fatalf("expect len 0 bytes but got %d. r.w=%d, r.r=%d", rb.Length(), rb.w, rb.r)
 	}
-	if rb.Free() != 64 {
+	if rb.Free() != 128 {
 		t.Fatalf("expect free 128 bytes but got %d. r.w=%d, r.r=%d", rb.Free(), rb.w, rb.r)
 	}
 	if rb.r != 0 {
@@ -464,7 +464,7 @@ func TestRingBuffer_ByteInterface(t *testing.T) {
 	if rb.Length() != 0 {
 		t.Fatalf("expect len 0 byte but got %d. r.w=%d, r.r=%d", rb.Length(), rb.w, rb.r)
 	}
-	if rb.Free() != 2 {
+	if rb.Free() != 4 {
 		t.Fatalf("expect free 4 byte but got %d. r.w=%d, r.r=%d", rb.Free(), rb.w, rb.r)
 	}
 	// check empty or full
@@ -476,22 +476,22 @@ func TestRingBuffer_ByteInterface(t *testing.T) {
 	}
 }
 
-func TestShrinkBuffer(t *testing.T) {
-	testStr := "Hello World!"
-	testCap := 1024
-
-	rb := New(testCap)
-	_, _ = rb.WriteString(testStr)
-	rb.PeekAll()
-	rb.Discard(len(testStr))
-	if rb.Cap() != testCap/2 {
-		t.Fatalf("expect buffer capacity %d, but got %d", testCap/2, rb.Cap())
-	}
-
-	_, _ = rb.WriteString(testStr)
-	rb.PeekAll()
-	rb.Reset()
-	if rb.Cap() != testCap/4 {
-		t.Fatalf("expect buffer capacity %d, but got %d", testCap/4, rb.Cap())
-	}
-}
+// func TestShrinkBuffer(t *testing.T) {
+// 	testStr := "Hello World!"
+// 	testCap := 1024
+//
+// 	rb := New(testCap)
+// 	_, _ = rb.WriteString(testStr)
+// 	rb.PeekAll()
+// 	rb.Discard(len(testStr))
+// 	if rb.Cap() != testCap/2 {
+// 		t.Fatalf("expect buffer capacity %d, but got %d", testCap/2, rb.Cap())
+// 	}
+//
+// 	_, _ = rb.WriteString(testStr)
+// 	rb.PeekAll()
+// 	rb.Reset()
+// 	if rb.Cap() != testCap/4 {
+// 		t.Fatalf("expect buffer capacity %d, but got %d", testCap/4, rb.Cap())
+// 	}
+// }