baize/framework/core/tag/assign/tag.go

package assign

import (
	"git.sxidc.com/go-framework/baize/framework/core/infrastructure/logger"
	"git.sxidc.com/go-tools/utils/reflectutils"
	"git.sxidc.com/go-tools/utils/strutils"
	"github.com/pkg/errors"
	"reflect"
	"strings"
	"time"
)

const (
	defaultStringSliceSeparator = "::"
	tagPartSeparator            = ";"
	tagPartKeyValueSeparator    = ":"
)

const (
	tagKey            = "assign"
	tagPartIgnore     = "-"
	tagPartToPackage  = "toPackage"
	tagPartToStruct   = "toStruct"
	tagPartToField    = "toField"
	tagPartTimeLayout = "timeLayout"
	tagPartJoinWith   = "joinWith"
	tagPartSplitWith  = "splitWith"
	tagPartTrim       = "trim"
	tagPartTrimPrefix = "trimPrefix"
	tagPartTrimSuffix = "trimSuffix"
)

type Tag struct {
	ToPackage  string
	ToStruct   string
	ToField    string
	TimeLayout string
	JoinWith   string
	SplitWith  string
	Trim       string
	TrimPrefix string
	TrimSuffix string
}

func parseTag(fromElemValue reflect.Value, toElemValue *reflect.Value, onParsedFieldTagFunc OnParsedFieldTagCallback) error {
	for i := 0; i < fromElemValue.NumField(); i++ {
		fromField := fromElemValue.Type().Field(i)
		fromFieldValue := fromElemValue.Field(i)

		// 无效值
		if !fromFieldValue.IsValid() {
			continue
		}

		if fromFieldValue.Kind() == reflect.Pointer && fromFieldValue.IsNil() {
			if !fromFieldValue.CanSet() {
				return errors.New("无法设置值，请检查是否传递的是非指针结构变量且字段为nil")
			}

			fromFieldValue.Set(reflect.New(fromField.Type.Elem()))
		}

		fromFieldElemValue := reflectutils.PointerValueElem(fromFieldValue)

		tagStr := fromField.Tag.Get(tagKey)

		// 结构类型的字段上没有添加Tag, 先尝试直接按照字段赋值
		if strutils.IsStringEmpty(tagStr) && fromFieldElemValue.Kind() == reflect.Struct &&
			!reflectutils.IsValueTime(fromFieldElemValue) {
			err := parseTag(fromFieldElemValue, toElemValue, onParsedFieldTagFunc)
			if err != nil {
				return err
			}

			continue
		}

		tag, err := parseFieldTag(fromField, tagStr)
		if err != nil {
			return err
		}

		if tag == nil {
			continue
		}

		if (strutils.IsStringNotEmpty(tag.ToPackage) && toElemValue.Type().PkgPath() != tag.ToPackage) ||
			(strutils.IsStringNotEmpty(tag.ToStruct) && toElemValue.Type().Name() != tag.ToStruct) {
			continue
		}

		toFieldValue := toElemValue.FieldByName(tag.ToField)

		// 不存在对应的字段
		if !toFieldValue.IsValid() {
			continue
		}

		toFieldElemValue := toFieldValue
		if toFieldValue.Kind() == reflect.Pointer {
			if !toFieldValue.IsValid() {
				continue
			}

			if !toFieldValue.CanSet() {
				continue
			}

			// 空值针，初始化
			if toFieldValue.IsNil() {
				toFieldValue.Set(reflect.New(toFieldValue.Type().Elem()))
			}

			toFieldElemValue = toFieldValue.Elem()
		}

		err = onParsedFieldTagFunc(fromField.Name, fromFieldElemValue, toFieldElemValue, tag)
		if err != nil {
			return err
		}
	}

	return nil
}

func parseFieldTag(field reflect.StructField, tagStr string) (*Tag, error) {
	if tagStr == tagPartIgnore {
		return nil, nil
	}

	tag := &Tag{
		ToPackage:  "",
		ToStruct:   "",
		ToField:    field.Name,
		TimeLayout: time.DateTime,
		JoinWith:   defaultStringSliceSeparator,
		SplitWith:  defaultStringSliceSeparator,
		Trim:       "",
		TrimPrefix: "",
		TrimSuffix: "",
	}

	if strutils.IsStringEmpty(tagStr) {
		return tag, nil
	}

	tagParts := strings.Split(tagStr, tagPartSeparator)
	if tagParts != nil || len(tagParts) != 0 {
		for _, tagPart := range tagParts {
			tagPartKeyValue := strings.SplitN(strings.TrimSpace(tagPart), tagPartKeyValueSeparator, 2)
			if tagPartKeyValue != nil && len(tagPartKeyValue) == 2 && strutils.IsStringNotEmpty(tagPartKeyValue[1]) {
				tagPartKeyValue[1] = strings.Trim(tagPartKeyValue[1], "'")
			}

			if strutils.IsStringEmpty(tagPartKeyValue[0]) {
				continue
			}

			switch tagPartKeyValue[0] {
			case tagPartToPackage:
				tag.ToStruct = tagPartKeyValue[1]
			case tagPartToStruct:
				tag.ToStruct = tagPartKeyValue[1]
			case tagPartToField:
				tag.ToField = tagPartKeyValue[1]
			case tagPartTimeLayout:
				tag.TimeLayout = tagPartKeyValue[1]
			case tagPartJoinWith:
				if strutils.IsStringEmpty(tagPartKeyValue[1]) {
					return nil, errors.New(tagPartJoinWith + "没有赋值分隔符")
				}

				tag.JoinWith = tagPartKeyValue[1]
			case tagPartSplitWith:
				if strutils.IsStringEmpty(tagPartKeyValue[1]) {
					return nil, errors.New(tagPartSplitWith + "没有赋值分隔符")
				}

				tag.SplitWith = tagPartKeyValue[1]
			case tagPartTrim:
				tag.Trim = tagPartKeyValue[1]
			case tagPartTrimPrefix:
				tag.TrimPrefix = tagPartKeyValue[1]
			case tagPartTrimSuffix:
				tag.TrimSuffix = tagPartKeyValue[1]
			default:
				err := errors.New(tagKey + "不支持的tag: " + tagPartKeyValue[0])
				logger.GetInstance().Error(err)
				continue
			}
		}
	}

	return tag, nil
}