GO 反射对性能的影响分析

func IsEmpty(val interface{}) bool {
	if val == nil {
		return true
	}
	switch v := val.(type) {
	case int:
		return v == int(0)
	case int8:
		return v == int8(0)
	case int16:
		return v == int16(0)
	case int32:
		return v == int32(0)
	case int64:
		return v == int64(0)
	case string:
		return v == ""
	default:
		return false
	}
}

// isEmpty gets whether the specified object is considered empty or not.
func isEmpty(object interface{}) bool {
	// get nil case out of the way
	if object == nil {
		return true
	}
	objValue := reflect.ValueOf(object)
	switch objValue.Kind() {
	// collection types are empty when they have no element
	case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice:
		return objValue.Len() == 0
		// pointers are empty if nil or if the value they point to is empty
	case reflect.Ptr:
		if objValue.IsNil() {
			return true
		}
		deref := objValue.Elem().Interface()
		return isEmpty(deref)
		// for all other types, compare against the zero value
	default:
		zero := reflect.Zero(objValue.Type())
		return reflect.DeepEqual(object, zero.Interface())
	}
}

const (
	IntZero     = int(0)
	Int8Zero    = int8(0)
	Int16Zero   = int16(0)
	Int32Zero   = int32(0)
	Int64Zero   = int64(0)
	UintZero    = uint(0)
	Uint8Zero   = uint8(0)
	Uint16Zero  = uint16(0)
	Uint32Zero  = uint32(0)
	Uint64Zero  = uint64(0)
	Float32Zero = float32(0)
	Float64Zero = float64(0)
	StringZero  = ""
)
func IsEmpty(data interface{}) bool {
	if data == nil {
		return false
	}
	switch v := data.(type) {
	case bool:
		return false
	case *bool:
		return v == nil
	case int:
		return v == IntZero
	case *int:
		return v == nil || *v == IntZero
	case int8:
		return v == Int8Zero
	case *int8:
		return v == nil || *v == Int8Zero
	case int16:
		return v == Int16Zero
	case *int16:
		return v == nil || *v == Int16Zero
	case int32:
		return v == Int32Zero
	case *int32:
		return v == nil || *v == Int32Zero
	case int64:
		return v == Int64Zero
	case *int64:
		return v == nil || *v == Int64Zero
	case uint:
		return v == UintZero
	case *uint:
		return v == nil || *v == UintZero
	case uint8:
		return v == Uint8Zero
	case *uint8:
		return v == nil || *v == Uint8Zero
	case uint16:
		return v == Uint16Zero
	case *uint16:
		return v == nil || *v == Uint16Zero
	case uint32:
		return v == Uint32Zero
	case *uint32:
		return v == nil || *v == Uint32Zero
	case uint64:
		return v == Uint64Zero
	case *uint64:
		return v == nil || *v == Uint64Zero
	case float32:
		return v == Float32Zero
	case *float32:
		return v == nil || *v == Float32Zero
	case float64:
		return v == Float64Zero
	case *float64:
		return v == nil || *v == Float64Zero
	case string:
		return v == StringZero
	case *string:
		return v == nil || *v == StringZero
	default:
		kind := reflect.TypeOf(data).Kind()
		if kind == reflect.Ptr {
			dataKind := reflect.ValueOf(data).Elem().Kind()
			if dataKind == reflect.Invalid || dataKind == reflect.Struct {
				return reflect.ValueOf(data).IsNil()
			} else {
				return false
			}
		} else if kind == reflect.Slice || kind == reflect.Map {
			// slice
			return reflect.ValueOf(data).Len() == 0
		} else if kind == reflect.Struct {
			// struct
			return false
		} else {
			panic("not support type. you can support by yourself")
		}
	}
}

func BenchmarkTestIsEmpty(t *testing.B) {
	v1 := false
	v2 := true
	var v3 *bool
	v4 := int(0)
	var v5 *int
	v6 := int64(0)
	var v7 *int64
	v8 := ""
	var v9 *string
	v10 := "test"
	v11 := float64(0.00)
	v12 := float64(0.01)
	testCases := []TestCase{
		{input: v1, want: false},
		{input: &v1, want: false},
		{input: v2, want: false},
		{input: &v2, want: false},
		{input: v3, want: true},
		{input: v4, want: true},
		{input: &v4, want: true},
		{input: v5, want: true},
		{input: int(1), want: false},
		{input: v6, want: true},
		{input: &v6, want: true},
		{input: v7, want: true},
		{input: int64(1), want: false},
		{input: v8, want: true},
		{input: &v8, want: true},
		{input: v9, want: true},
		{input: v10, want: false},
		{input: &v10, want: false},
		{input: v11, want: true},
		{input: &v11, want: true},
		{input: v12, want: false},
		{input: &v12, want: false},
	}
	for i, testCase := range testCases {
		result := IsEmpty(testCases[i].input)
		assert.Equal(t, testCase.want, result)
	}
}
func BenchmarkTestIsEmptyV1(t *testing.B) {
	v1 := false
	v2 := true
	var v3 *bool
	v4 := int(0)
	var v5 *int
	v6 := int64(0)
	var v7 *int64
	v8 := ""
	var v9 *string
	v10 := "test"
	v11 := float64(0.00)
	v12 := float64(0.01)
	testCases := []TestCase{
		{input: v1, want: true},
		{input: &v1, want: true},
		{input: v2, want: false},
		{input: &v2, want: false},
		{input: v3, want: true},
		{input: v4, want: true},
		{input: &v4, want: true},
		{input: v5, want: true},
		{input: int(1), want: false},
		{input: v6, want: true},
		{input: &v6, want: true},
		{input: v7, want: true},
		{input: int64(1), want: false},
		{input: v8, want: true},
		{input: &v8, want: true},
		{input: v9, want: true},
		{input: v10, want: false},
		{input: &v10, want: false},
		{input: v11, want: true},
		{input: &v11, want: true},
		{input: v12, want: false},
		{input: &v12, want: false},
	}
	for i, testCase := range testCases {
		result := IsEmptyV1(testCases[i].input)
		assert.Equal(t, testCase.want, result)
	}
}

go test -bench=.  -benchmem