gopkgs/util/struct.go

package util

import (
	"fmt"
	"reflect"
)

func CopyStructSameField(dst interface{}, src interface{}) error {
	d := reflect.ValueOf(dst)
	if d.Kind() != reflect.Ptr {
		return fmt.Errorf("dst is not ptr")
	}
	d = d.Elem()
	if d.Kind() != reflect.Struct {
		return fmt.Errorf("dst is not struct")
	}

	s := reflect.ValueOf(src)
	if s.Kind() == reflect.Ptr {
		s = s.Elem()
	}
	if s.Kind() != reflect.Struct {
		return fmt.Errorf("src is not struct")
	}
	srcmap := map[string]reflect.Value{}
	numField := s.NumField()
	for i := 0; i < numField; i++ {
		srcmap[s.Type().Field(i).Name] = s.Field(i)
	}

	numField = d.NumField()
	for i := 0; i < numField; i++ {
		name := d.Type().Field(i).Name
		if v, ok := srcmap[name]; ok {
			if v.Type().Kind() == d.Type().Field(i).Type.Kind() {
				if v.Type().Kind() == reflect.Struct {
					CopyStructSameField(d.Field(i).Addr().Interface(), v.Interface())
				} else if v.Type().Kind() == reflect.Slice {
					d.Field(i).Set(reflect.MakeSlice(d.Field(i).Type(), 0, v.Len()))
					if t, err := CopySlice(d.Field(i).Interface(), v.Interface()); err == nil {
						tmp := reflect.ValueOf(t)
						d.Field(i).Set(reflect.MakeSlice(d.Field(i).Type(), tmp.Len(), tmp.Len()))
						reflect.Copy(d.Field(i), reflect.ValueOf(t))
					}
				} else {
					d.Field(i).Set(v)
				}
			}
		}
	}
	return nil
}

func CopySlice(dst interface{}, src interface{}) (ddd interface{}, err error) {
	d := reflect.ValueOf(dst)
	if d.Kind() == reflect.Ptr {
		d = d.Elem()
	}
	if d.Kind() != reflect.Slice {
		return dst, fmt.Errorf("dst is not slice")
	}

	s := reflect.ValueOf(src)
	if s.Kind() == reflect.Ptr {
		s = s.Elem()
	}
	if s.Kind() != reflect.Slice {
		return dst, fmt.Errorf("src is not slice")
	}

	count := s.Len()
	for i := 0; i < count; i++ {
		t := reflect.New(d.Type().Elem())
		if t.Type().Elem().Kind() == reflect.Struct && s.Index(i).Type().Kind() == reflect.Struct {
			CopyStructSameField(t.Interface(), s.Index(i).Interface())
		} else if t.Kind() == reflect.Slice && s.Index(i).Kind() == reflect.Slice {
			CopySlice(t, s.Field(i))
		} else if t.Kind() != reflect.Slice && t.Kind() != reflect.Struct && s.Index(i).Kind() != reflect.Slice && s.Index(i).Kind() != reflect.Struct {
			t.Set(s.Field(i))
		}
		d = reflect.Append(d, t.Elem())
	}
	return d.Interface(), nil
}