Files
mayfly-go/base/utils/struct_utils.go

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2020-09-01 10:34:11 +08:00
package utils
import (
"database/sql"
"encoding/json"
"errors"
"fmt"
"reflect"
"strconv"
"strings"
)
// Copy copy things引用至copier
func Copy(toValue interface{}, fromValue interface{}) (err error) {
var (
isSlice bool
amount = 1
from = Indirect(reflect.ValueOf(fromValue))
to = Indirect(reflect.ValueOf(toValue))
)
if !to.CanAddr() {
return errors.New("copy to value is unaddressable")
}
// Return is from value is invalid
if !from.IsValid() {
return
}
fromType := IndirectType(from.Type())
toType := IndirectType(to.Type())
// Just set it if possible to assign
// And need to do copy anyway if the type is struct
if fromType.Kind() != reflect.Struct && from.Type().AssignableTo(to.Type()) {
to.Set(from)
return
}
if fromType.Kind() != reflect.Struct || toType.Kind() != reflect.Struct {
return
}
if to.Kind() == reflect.Slice {
isSlice = true
if from.Kind() == reflect.Slice {
amount = from.Len()
}
}
for i := 0; i < amount; i++ {
var dest, source reflect.Value
if isSlice {
// source
if from.Kind() == reflect.Slice {
source = Indirect(from.Index(i))
} else {
source = Indirect(from)
}
// dest
dest = Indirect(reflect.New(toType).Elem())
} else {
source = Indirect(from)
dest = Indirect(to)
}
// check source
if source.IsValid() {
fromTypeFields := deepFields(fromType)
//fmt.Printf("%#v", fromTypeFields)
// Copy from field to field or method
for _, field := range fromTypeFields {
name := field.Name
if fromField := source.FieldByName(name); fromField.IsValid() {
// has field
if toField := dest.FieldByName(name); toField.IsValid() {
if toField.CanSet() {
if !set(toField, fromField) {
if err := Copy(toField.Addr().Interface(), fromField.Interface()); err != nil {
return err
}
}
}
} else {
// try to set to method
var toMethod reflect.Value
if dest.CanAddr() {
toMethod = dest.Addr().MethodByName(name)
} else {
toMethod = dest.MethodByName(name)
}
if toMethod.IsValid() && toMethod.Type().NumIn() == 1 && fromField.Type().AssignableTo(toMethod.Type().In(0)) {
toMethod.Call([]reflect.Value{fromField})
}
}
}
}
// Copy from method to field
for _, field := range deepFields(toType) {
name := field.Name
var fromMethod reflect.Value
if source.CanAddr() {
fromMethod = source.Addr().MethodByName(name)
} else {
fromMethod = source.MethodByName(name)
}
if fromMethod.IsValid() && fromMethod.Type().NumIn() == 0 && fromMethod.Type().NumOut() == 1 {
if toField := dest.FieldByName(name); toField.IsValid() && toField.CanSet() {
values := fromMethod.Call([]reflect.Value{})
if len(values) >= 1 {
set(toField, values[0])
}
}
}
}
}
if isSlice {
if dest.Addr().Type().AssignableTo(to.Type().Elem()) {
to.Set(reflect.Append(to, dest.Addr()))
} else if dest.Type().AssignableTo(to.Type().Elem()) {
to.Set(reflect.Append(to, dest))
}
}
}
return
}
func deepFields(reflectType reflect.Type) []reflect.StructField {
var fields []reflect.StructField
if reflectType = IndirectType(reflectType); reflectType.Kind() == reflect.Struct {
for i := 0; i < reflectType.NumField(); i++ {
v := reflectType.Field(i)
if v.Anonymous {
fields = append(fields, deepFields(v.Type)...)
} else {
fields = append(fields, v)
}
}
}
return fields
}
func Indirect(reflectValue reflect.Value) reflect.Value {
for reflectValue.Kind() == reflect.Ptr {
reflectValue = reflectValue.Elem()
}
return reflectValue
}
func IndirectType(reflectType reflect.Type) reflect.Type {
for reflectType.Kind() == reflect.Ptr || reflectType.Kind() == reflect.Slice {
reflectType = reflectType.Elem()
}
return reflectType
}
func set(to, from reflect.Value) bool {
if from.IsValid() {
if to.Kind() == reflect.Ptr {
//set `to` to nil if from is nil
if from.Kind() == reflect.Ptr && from.IsNil() {
to.Set(reflect.Zero(to.Type()))
return true
} else if to.IsNil() {
to.Set(reflect.New(to.Type().Elem()))
}
to = to.Elem()
}
if from.Type().ConvertibleTo(to.Type()) {
to.Set(from.Convert(to.Type()))
} else if scanner, ok := to.Addr().Interface().(sql.Scanner); ok {
err := scanner.Scan(from.Interface())
if err != nil {
return false
}
} else if from.Kind() == reflect.Ptr {
return set(to, from.Elem())
} else {
return false
}
}
return true
}
func Map2Struct(m map[string]interface{}, s interface{}) error {
toValue := Indirect(reflect.ValueOf(s))
if !toValue.CanAddr() {
return errors.New("to value is unaddressable")
}
innerStructMaps := getInnerStructMaps(m)
if len(innerStructMaps) != 0 {
for k, v := range innerStructMaps {
var fieldV reflect.Value
if strings.Contains(k, ".") {
fieldV = getFiledValueByPath(k, toValue)
} else {
fieldV = toValue.FieldByName(k)
}
if !fieldV.CanSet() || !fieldV.CanAddr() {
continue
}
fieldT := fieldV.Type().Elem()
if fieldT.Kind() != reflect.Struct {
return errors.New(k + "不是结构体")
}
// 如果值为nil则默认创建一个并赋值
if fieldV.IsNil() {
fieldV.Set(reflect.New(fieldT))
}
err := Map2Struct(v, fieldV.Addr().Interface())
if err != nil {
return err
}
}
}
var err error
for k, v := range m {
if v == nil {
continue
}
k = strings.Title(k)
// 如果key含有下划线则将其转为驼峰
if strings.Contains(k, "_") {
k = Case2Camel(k)
}
fieldV := toValue.FieldByName(k)
if !fieldV.CanSet() {
continue
}
err = decode(k, v, fieldV)
if err != nil {
return err
}
}
return nil
}
func Maps2Structs(maps []map[string]interface{}, structs interface{}) error {
structsV := reflect.Indirect(reflect.ValueOf(structs))
valType := structsV.Type()
valElemType := valType.Elem()
sliceType := reflect.SliceOf(valElemType)
length := len(maps)
valSlice := structsV
if valSlice.IsNil() {
// Make a new slice to hold our result, same size as the original data.
valSlice = reflect.MakeSlice(sliceType, length, length)
}
for i := 0; i < length; i++ {
err := Map2Struct(maps[i], valSlice.Index(i).Addr().Interface())
if err != nil {
return err
}
}
structsV.Set(valSlice)
return nil
}
func getFiledValueByPath(path string, value reflect.Value) reflect.Value {
split := strings.Split(path, ".")
for _, v := range split {
if value.Type().Kind() == reflect.Ptr {
// 如果值为nil则创建并赋值
if value.IsNil() {
value.Set(reflect.New(IndirectType(value.Type())))
}
value = value.Elem()
}
value = value.FieldByName(v)
}
return value
}
func getInnerStructMaps(m map[string]interface{}) map[string]map[string]interface{} {
key2map := make(map[string]map[string]interface{})
for k, v := range m {
if !strings.Contains(k, ".") {
continue
}
lastIndex := strings.LastIndex(k, ".")
prefix := k[0:lastIndex]
m2 := key2map[prefix]
if m2 == nil {
key2map[prefix] = map[string]interface{}{k[lastIndex+1:]: v}
} else {
m2[k[lastIndex+1:]] = v
}
delete(m, k)
}
return key2map
}
// decode等方法摘抄自mapstructure库
func decode(name string, input interface{}, outVal reflect.Value) error {
var inputVal reflect.Value
if input != nil {
inputVal = reflect.ValueOf(input)
// We need to check here if input is a typed nil. Typed nils won't
// match the "input == nil" below so we check that here.
if inputVal.Kind() == reflect.Ptr && inputVal.IsNil() {
input = nil
}
}
if !inputVal.IsValid() {
// If the input value is invalid, then we just set the value
// to be the zero value.
outVal.Set(reflect.Zero(outVal.Type()))
return nil
}
var err error
outputKind := getKind(outVal)
switch outputKind {
case reflect.Int:
err = decodeInt(name, input, outVal)
case reflect.Uint:
err = decodeUint(name, input, outVal)
case reflect.Float32:
err = decodeFloat(name, input, outVal)
case reflect.String:
err = decodeString(name, input, outVal)
case reflect.Ptr:
_, err = decodePtr(name, input, outVal)
default:
// If we reached this point then we weren't able to decode it
return fmt.Errorf("%s: unsupported type: %s", name, outputKind)
}
return err
}
func decodeInt(name string, data interface{}, val reflect.Value) error {
dataVal := reflect.Indirect(reflect.ValueOf(data))
dataKind := getKind(dataVal)
dataType := dataVal.Type()
switch {
case dataKind == reflect.Int:
val.SetInt(dataVal.Int())
case dataKind == reflect.Uint:
val.SetInt(int64(dataVal.Uint()))
case dataKind == reflect.Float32:
val.SetInt(int64(dataVal.Float()))
case dataKind == reflect.Bool:
if dataVal.Bool() {
val.SetInt(1)
} else {
val.SetInt(0)
}
case dataKind == reflect.String:
i, err := strconv.ParseInt(dataVal.String(), 0, val.Type().Bits())
if err == nil {
val.SetInt(i)
} else {
return fmt.Errorf("cannot parse '%s' as int: %s", name, err)
}
case dataType.PkgPath() == "encoding/json" && dataType.Name() == "Number":
jn := data.(json.Number)
i, err := jn.Int64()
if err != nil {
return fmt.Errorf(
"error decoding json.Number into %s: %s", name, err)
}
val.SetInt(i)
default:
return fmt.Errorf(
"'%s' expected type '%s', got unconvertible type '%s'",
name, val.Type(), dataVal.Type())
}
return nil
}
func decodeUint(name string, data interface{}, val reflect.Value) error {
dataVal := reflect.Indirect(reflect.ValueOf(data))
dataKind := getKind(dataVal)
dataType := dataVal.Type()
switch {
case dataKind == reflect.Int:
i := dataVal.Int()
if i < 0 {
return fmt.Errorf("cannot parse '%s', %d overflows uint",
name, i)
}
val.SetUint(uint64(i))
case dataKind == reflect.Uint:
val.SetUint(dataVal.Uint())
case dataKind == reflect.Float32:
f := dataVal.Float()
if f < 0 {
return fmt.Errorf("cannot parse '%s', %f overflows uint",
name, f)
}
val.SetUint(uint64(f))
case dataKind == reflect.Bool:
if dataVal.Bool() {
val.SetUint(1)
} else {
val.SetUint(0)
}
case dataKind == reflect.String:
i, err := strconv.ParseUint(dataVal.String(), 0, val.Type().Bits())
if err == nil {
val.SetUint(i)
} else {
return fmt.Errorf("cannot parse '%s' as uint: %s", name, err)
}
case dataType.PkgPath() == "encoding/json" && dataType.Name() == "Number":
jn := data.(json.Number)
i, err := jn.Int64()
if err != nil {
return fmt.Errorf(
"error decoding json.Number into %s: %s", name, err)
}
if i < 0 {
return fmt.Errorf("cannot parse '%s', %d overflows uint",
name, i)
}
val.SetUint(uint64(i))
default:
return fmt.Errorf(
"'%s' expected type '%s', got unconvertible type '%s'",
name, val.Type(), dataVal.Type())
}
return nil
}
func decodeFloat(name string, data interface{}, val reflect.Value) error {
dataVal := reflect.Indirect(reflect.ValueOf(data))
dataKind := getKind(dataVal)
dataType := dataVal.Type()
switch {
case dataKind == reflect.Int:
val.SetFloat(float64(dataVal.Int()))
case dataKind == reflect.Uint:
val.SetFloat(float64(dataVal.Uint()))
case dataKind == reflect.Float32:
val.SetFloat(dataVal.Float())
case dataKind == reflect.Bool:
if dataVal.Bool() {
val.SetFloat(1)
} else {
val.SetFloat(0)
}
case dataKind == reflect.String:
f, err := strconv.ParseFloat(dataVal.String(), val.Type().Bits())
if err == nil {
val.SetFloat(f)
} else {
return fmt.Errorf("cannot parse '%s' as float: %s", name, err)
}
case dataType.PkgPath() == "encoding/json" && dataType.Name() == "Number":
jn := data.(json.Number)
i, err := jn.Float64()
if err != nil {
return fmt.Errorf(
"error decoding json.Number into %s: %s", name, err)
}
val.SetFloat(i)
default:
return fmt.Errorf(
"'%s' expected type '%s', got unconvertible type '%s'",
name, val.Type(), dataVal.Type())
}
return nil
}
func decodeString(name string, data interface{}, val reflect.Value) error {
dataVal := reflect.Indirect(reflect.ValueOf(data))
dataKind := getKind(dataVal)
converted := true
switch {
case dataKind == reflect.String:
val.SetString(dataVal.String())
case dataKind == reflect.Bool:
if dataVal.Bool() {
val.SetString("1")
} else {
val.SetString("0")
}
case dataKind == reflect.Int:
val.SetString(strconv.FormatInt(dataVal.Int(), 10))
case dataKind == reflect.Uint:
val.SetString(strconv.FormatUint(dataVal.Uint(), 10))
case dataKind == reflect.Float32:
val.SetString(strconv.FormatFloat(dataVal.Float(), 'f', -1, 64))
case dataKind == reflect.Slice,
dataKind == reflect.Array:
dataType := dataVal.Type()
elemKind := dataType.Elem().Kind()
switch elemKind {
case reflect.Uint8:
var uints []uint8
if dataKind == reflect.Array {
uints = make([]uint8, dataVal.Len(), dataVal.Len())
for i := range uints {
uints[i] = dataVal.Index(i).Interface().(uint8)
}
} else {
uints = dataVal.Interface().([]uint8)
}
val.SetString(string(uints))
default:
converted = false
}
default:
converted = false
}
if !converted {
return fmt.Errorf(
"'%s' expected type '%s', got unconvertible type '%s'",
name, val.Type(), dataVal.Type())
}
return nil
}
func decodePtr(name string, data interface{}, val reflect.Value) (bool, error) {
// If the input data is nil, then we want to just set the output
// pointer to be nil as well.
isNil := data == nil
if !isNil {
switch v := reflect.Indirect(reflect.ValueOf(data)); v.Kind() {
case reflect.Chan,
reflect.Func,
reflect.Interface,
reflect.Map,
reflect.Ptr,
reflect.Slice:
isNil = v.IsNil()
}
}
if isNil {
if !val.IsNil() && val.CanSet() {
nilValue := reflect.New(val.Type()).Elem()
val.Set(nilValue)
}
return true, nil
}
// Create an element of the concrete (non pointer) type and decode
// into that. Then set the value of the pointer to this type.
valType := val.Type()
valElemType := valType.Elem()
if val.CanSet() {
realVal := val
if realVal.IsNil() {
realVal = reflect.New(valElemType)
}
if err := decode(name, data, reflect.Indirect(realVal)); err != nil {
return false, err
}
val.Set(realVal)
} else {
if err := decode(name, data, reflect.Indirect(val)); err != nil {
return false, err
}
}
return false, nil
}
func getKind(val reflect.Value) reflect.Kind {
kind := val.Kind()
switch {
case kind >= reflect.Int && kind <= reflect.Int64:
return reflect.Int
case kind >= reflect.Uint && kind <= reflect.Uint64:
return reflect.Uint
case kind >= reflect.Float32 && kind <= reflect.Float64:
return reflect.Float32
default:
return kind
}
}
// 下划线写法转为驼峰写法
func Case2Camel(name string) string {
name = strings.Replace(name, "_", " ", -1)
name = strings.Title(name)
return strings.Replace(name, " ", "", -1)
}
func isBlank(value reflect.Value) bool {
switch value.Kind() {
case reflect.String:
return value.Len() == 0
case reflect.Bool:
return !value.Bool()
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return value.Int() == 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
return value.Uint() == 0
case reflect.Float32, reflect.Float64:
return value.Float() == 0
case reflect.Interface, reflect.Ptr:
return value.IsNil()
}
return reflect.DeepEqual(value.Interface(), reflect.Zero(value.Type()).Interface())
}