fix/slice: support empty slice in hight level api

Author: chenjunbiao

basic.go

@@ -130,28 +130,24 @@ func (e *basicEncoderImpl) encodeBasic(input interface{}, signals []*PrimitivePa
 
 // encodeBasicSlice encode reflect.Value of slice, and inserting signals
 func (e *basicEncoderImpl) encodeBasicSlice(value reflect.Value, signals []*PrimitivePacketEncoder) ([]byte, error) {
-	if value.Len() == 0 {
-		return nil, fmt.Errorf("no item is slice")
-	}
-
 	var nodeEncoder *NodePacketEncoder
 
-	switch value.Index(0).Kind() {
-	case reflect.String:
+	switch value.Type() {
+	case utils.TyeOfStringSlice:
 		nodeEncoder = e.encodeBasicStringSlice(value)
-	case reflect.Int32:
+	case utils.TyeOfInt32Slice:
 		nodeEncoder = e.encodeBasicInt32Slice(value)
-	case reflect.Uint32:
+	case utils.TyeOfUint32Slice:
 		nodeEncoder = e.encodeBasicUint32Slice(value)
-	case reflect.Int64:
+	case utils.TyeOfInt64Slice:
 		nodeEncoder = e.encodeBasicInt64Slice(value)
-	case reflect.Uint64:
+	case utils.TyeOfUint64Slice:
 		nodeEncoder = e.encodeBasicUint64Slice(value)
-	case reflect.Float32:
+	case utils.TyeOfFloat32Slice:
 		nodeEncoder = e.encodeBasicFloat32Slice(value)
-	case reflect.Float64:
+	case utils.TyeOfFloat64Slice:
 		nodeEncoder = e.encodeBasicFloat64Slice(value)
-	case reflect.Bool:
+	case utils.TyeOfBoolSlice:
 		nodeEncoder = e.encodeBasicBoolSlice(value)
 	default:
 		panic(fmt.Errorf("marshal error, no matching type in SliceTestData: %v", value.Index(0).Kind()))

internal/utils/common.go

@@ -25,3 +25,27 @@ const RootToken byte = 0x01
 
 // TypeOfByteSlice Type of []byte
 var TypeOfByteSlice = reflect.TypeOf([]byte{})
+
+// TyeOfStringSlice Type of []string{}
+var TyeOfStringSlice = reflect.TypeOf([]string{})
+
+// TyeOfInt32Slice Type of []int32{}
+var TyeOfInt32Slice = reflect.TypeOf([]int32{})
+
+// TyeOfUint32Slice Type of []uint32{}
+var TyeOfUint32Slice = reflect.TypeOf([]uint32{})
+
+// TyeOfInt64Slice Type of []int64{}
+var TyeOfInt64Slice = reflect.TypeOf([]int64{})
+
+// TyeOfUint64Slice Type of []uint64{}
+var TyeOfUint64Slice = reflect.TypeOf([]uint64{})
+
+// TyeOfFloat32Slice Type of []float32{}
+var TyeOfFloat32Slice = reflect.TypeOf([]float32{})
+
+// TyeOfFloat64Slice Type of []float64{}
+var TyeOfFloat64Slice = reflect.TypeOf([]float64{})
+
+// TyeOfBoolSlice Type of []bool{}
+var TyeOfBoolSlice = reflect.TypeOf([]bool{})

types.go

@@ -31,9 +31,10 @@ func ToInt32Slice(v []byte) ([]int32, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
+
 	result := make([]int32, 0)
 	for _, p := range packet.PrimitivePackets {
 		v, _ := p.ToInt32()
@@ -61,7 +62,7 @@ func ToUInt32Slice(v []byte) ([]uint32, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]uint32, 0)
@@ -91,7 +92,7 @@ func ToInt64Slice(v []byte) ([]int64, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]int64, 0)
@@ -121,7 +122,7 @@ func ToUInt64Slice(v []byte) ([]uint64, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]uint64, 0)
@@ -151,7 +152,7 @@ func ToFloat32Slice(v []byte) ([]float32, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]float32, 0)
@@ -181,7 +182,7 @@ func ToFloat64Slice(v []byte) ([]float64, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]float64, 0)
@@ -211,7 +212,7 @@ func ToBoolSlice(v []byte) ([]bool, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]bool, 0)
@@ -241,7 +242,7 @@ func ToUTF8StringSlice(v []byte) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	if !packet.IsSlice() || len(packet.PrimitivePackets) <= 0 {
+	if !packet.IsSlice() {
 		return nil, fmt.Errorf("v not a slice: %v", utils.FormatBytes(v))
 	}
 	result := make([]string, 0)