fix(protocol): Peek() returns non-nil if key exists

Author: xiaost

pkg/network/netpoll/transport_test.go

@@ -124,7 +124,7 @@ func TestTransport(t *testing.T) {
 	t.Run("TestExceptionCase", func(t *testing.T) {
 		assert.Panic(t, func() { // listen err
 			transporter := NewTransporter(&config.Options{
-				Network: "unknow",
+				Network: "unknown",
 			})
 			transporter.ListenAndServe(func(ctx context.Context, conn interface{}) error {
 				return nil

pkg/protocol/args.go

@@ -54,8 +54,6 @@ const (
 	ArgsHasValue = false
 )
 
-var nilByteSlice = []byte{}
-
 type argsScanner struct {
 	b []byte
 }
@@ -167,9 +165,15 @@ func allocArg(h []argsKV) ([]argsKV, *argsKV) {
 	n := len(h)
 	if cap(h) > n {
 		h = h[:n+1]
-	} else {
-		h = append(h, argsKV{})
+		kv := &h[n]
+		if kv.value == nil {
+			// bytes in value would be reused, and it's not always nil
+			// only set to empty when it's nil
+			kv.value = []byte{}
+		}
+		return h, kv
 	}
+	h = append(h, argsKV{value: []byte{}})
 	return h, &h[n]
 }
 
@@ -228,10 +232,7 @@ func peekArgBytes(h []argsKV, k []byte) []byte {
 	for i, n := 0, len(h); i < n; i++ {
 		kv := &h[i]
 		if bytes.Equal(kv.key, k) {
-			if kv.value != nil {
-				return kv.value
-			}
-			return nilByteSlice
+			return kv.value
 		}
 	}
 	return nil

pkg/protocol/args_test.go

@@ -130,6 +130,37 @@ func TestArgsVisitAll(t *testing.T) {
 	assert.DeepEqual(t, []string{"cloudwego", "hertz", "hello", "world"}, s)
 }
 
+func TestArgsCopyTo(t *testing.T) {
+	var a Args
+	a.Add("cloudwego", "")
+	a.Add("hello", "world")
+
+	var b Args
+	a.CopyTo(&b)
+	assert.Assert(t, b.Len() == 2)
+	assert.Assert(t, a.Peek("cloudwego") != nil && len(a.Peek("cloudwego")) == 0)
+	assert.Assert(t, string(a.Peek("hello")) == "world")
+	assert.Assert(t, a.Peek("key-not-exists") == nil)
+}
+
+func TestArgsPeek(t *testing.T) {
+	var a Args
+	a.Add("cloudwego", "")
+	a.Add("hello", "world")
+
+	assert.Assert(t, a.Peek("cloudwego") != nil && len(a.Peek("cloudwego")) == 0)
+	assert.Assert(t, string(a.Peek("hello")) == "world")
+	assert.Assert(t, a.Peek("key-not-exists") == nil)
+
+	// reset and reuse
+	a.Reset()
+	a.Add("cloudwego", "")
+	a.Add("hello", "world")
+	assert.Assert(t, a.Peek("cloudwego") != nil && len(a.Peek("cloudwego")) == 0)
+	assert.Assert(t, string(a.Peek("hello")) == "world")
+	assert.Assert(t, a.Peek("key-not-exists") == nil)
+}
+
 func TestArgsPeekMulti(t *testing.T) {
 	var a Args
 	a.Add("cloudwego", "hertz")
@@ -141,7 +172,7 @@ func TestArgsPeekMulti(t *testing.T) {
 	expectedVV := [][]byte{
 		[]byte("hertz"),
 		[]byte("kitex"),
-		[]byte(nil),
+		[]byte{},
 	}
 	assert.DeepEqual(t, expectedVV, vv)
 

pkg/protocol/trailer.go

@@ -163,7 +163,7 @@ func (t *Trailer) SetTrailers(trailers []byte) (err error) {
 		}
 
 		utils.NormalizeHeaderKey(trailerKey, t.disableNormalizing)
-		err = t.addArgBytes(trailerKey, nilByteSlice, argsNoValue)
+		err = t.addArgBytes(trailerKey, nil, argsNoValue)
 	}
 	return
 }