forked from gogf/gf
/
gconv_struct.go
464 lines (437 loc) · 14.9 KB
/
gconv_struct.go
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// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.
package gconv
import (
"fmt"
"github.com/gogf/gf/errors/gerror"
"github.com/gogf/gf/internal/empty"
"github.com/gogf/gf/internal/json"
"github.com/gogf/gf/internal/structs"
"reflect"
"strings"
"github.com/gogf/gf/internal/utils"
)
// Struct maps the params key-value pairs to the corresponding struct object's attributes.
// The third parameter `mapping` is unnecessary, indicating the mapping rules between the
// custom key name and the attribute name(case sensitive).
//
// Note:
// 1. The `params` can be any type of map/struct, usually a map.
// 2. The `pointer` should be type of *struct/**struct, which is a pointer to struct object
// or struct pointer.
// 3. Only the public attributes of struct object can be mapped.
// 4. If `params` is a map, the key of the map `params` can be lowercase.
// It will automatically convert the first letter of the key to uppercase
// in mapping procedure to do the matching.
// It ignores the map key, if it does not match.
func Struct(params interface{}, pointer interface{}, mapping ...map[string]string) (err error) {
var keyToAttributeNameMapping map[string]string
if len(mapping) > 0 {
keyToAttributeNameMapping = mapping[0]
}
return doStruct(params, pointer, keyToAttributeNameMapping, "")
}
// StructTag acts as Struct but also with support for priority tag feature, which retrieves the
// specified tags for `params` key-value items to struct attribute names mapping.
// The parameter `priorityTag` supports multiple tags that can be joined with char ','.
func StructTag(params interface{}, pointer interface{}, priorityTag string) (err error) {
return doStruct(params, pointer, nil, priorityTag)
}
// StructDeep do Struct function recursively.
// Deprecated, use Struct instead.
func StructDeep(params interface{}, pointer interface{}, mapping ...map[string]string) error {
var keyToAttributeNameMapping map[string]string
if len(mapping) > 0 {
keyToAttributeNameMapping = mapping[0]
}
return doStruct(params, pointer, keyToAttributeNameMapping, "")
}
// doStruct is the core internal converting function for any data to struct.
func doStruct(params interface{}, pointer interface{}, mapping map[string]string, priorityTag string) (err error) {
if params == nil {
// If `params` is nil, no conversion.
return nil
}
if pointer == nil {
return gerror.New("object pointer cannot be nil")
}
defer func() {
// Catch the panic, especially the reflect operation panics.
if exception := recover(); exception != nil {
if e, ok := exception.(errorStack); ok {
err = e
} else {
err = gerror.NewSkipf(1, "%v", exception)
}
}
}()
// If given `params` is JSON, it then uses json.Unmarshal doing the converting.
switch r := params.(type) {
case []byte:
if json.Valid(r) {
if rv, ok := pointer.(reflect.Value); ok {
if rv.Kind() == reflect.Ptr {
return json.Unmarshal(r, rv.Interface())
}
} else {
return json.Unmarshal(r, pointer)
}
}
case string:
if paramsBytes := []byte(r); json.Valid(paramsBytes) {
if rv, ok := pointer.(reflect.Value); ok {
if rv.Kind() == reflect.Ptr {
return json.Unmarshal(paramsBytes, rv.Interface())
}
} else {
return json.Unmarshal(paramsBytes, pointer)
}
}
}
var (
paramsReflectValue reflect.Value
pointerReflectValue reflect.Value
pointerReflectKind reflect.Kind
pointerElemReflectValue reflect.Value // The pointed element.
)
if v, ok := params.(reflect.Value); ok {
paramsReflectValue = v
} else {
paramsReflectValue = reflect.ValueOf(params)
}
if v, ok := pointer.(reflect.Value); ok {
pointerReflectValue = v
pointerElemReflectValue = v
} else {
pointerReflectValue = reflect.ValueOf(pointer)
pointerReflectKind = pointerReflectValue.Kind()
if pointerReflectKind != reflect.Ptr {
return gerror.Newf("object pointer should be type of '*struct', but got '%v'", pointerReflectKind)
}
// Using IsNil on reflect.Ptr variable is OK.
if !pointerReflectValue.IsValid() || pointerReflectValue.IsNil() {
return gerror.New("object pointer cannot be nil")
}
pointerElemReflectValue = pointerReflectValue.Elem()
}
// If `params` and `pointer` are the same type, the do directly assignment.
// For performance enhancement purpose.
if pointerElemReflectValue.IsValid() && pointerElemReflectValue.Type() == paramsReflectValue.Type() {
pointerElemReflectValue.Set(paramsReflectValue)
return nil
}
// Normal unmarshalling interfaces checks.
if err, ok := bindVarToReflectValueWithInterfaceCheck(pointerReflectValue, params); ok {
return err
}
// It automatically creates struct object if necessary.
// For example, if `pointer` is **User, then `elem` is *User, which is a pointer to User.
if pointerElemReflectValue.Kind() == reflect.Ptr {
if !pointerElemReflectValue.IsValid() || pointerElemReflectValue.IsNil() {
e := reflect.New(pointerElemReflectValue.Type().Elem()).Elem()
pointerElemReflectValue.Set(e.Addr())
}
//if v, ok := pointerElemReflectValue.Interface().(apiUnmarshalValue); ok {
// return v.UnmarshalValue(params)
//}
// Note that it's `pointerElemReflectValue` here not `pointerReflectValue`.
if err, ok := bindVarToReflectValueWithInterfaceCheck(pointerElemReflectValue, params); ok {
return err
}
// Retrieve its element, may be struct at last.
pointerElemReflectValue = pointerElemReflectValue.Elem()
}
// paramsMap is the map[string]interface{} type variable for params.
// DO NOT use MapDeep here.
paramsMap := Map(params)
if paramsMap == nil {
return gerror.Newf("convert params to map failed: %v", params)
}
// It only performs one converting to the same attribute.
// doneMap is used to check repeated converting, its key is the real attribute name
// of the struct.
doneMap := make(map[string]struct{})
// The key of the attrMap is the attribute name of the struct,
// and the value is its replaced name for later comparison to improve performance.
var (
tempName string
elemFieldType reflect.StructField
elemFieldValue reflect.Value
elemType = pointerElemReflectValue.Type()
attrMap = make(map[string]string)
)
for i := 0; i < pointerElemReflectValue.NumField(); i++ {
elemFieldType = elemType.Field(i)
// Only do converting to public attributes.
if !utils.IsLetterUpper(elemFieldType.Name[0]) {
continue
}
// Maybe it's struct/*struct embedded.
if elemFieldType.Anonymous {
elemFieldValue = pointerElemReflectValue.Field(i)
// Ignore the interface attribute if it's nil.
if elemFieldValue.Kind() == reflect.Interface {
elemFieldValue = elemFieldValue.Elem()
if !elemFieldValue.IsValid() {
continue
}
}
if err = doStruct(paramsMap, elemFieldValue, mapping, priorityTag); err != nil {
return err
}
} else {
tempName = elemFieldType.Name
attrMap[tempName] = utils.RemoveSymbols(tempName)
}
}
if len(attrMap) == 0 {
return nil
}
// The key of the tagMap is the attribute name of the struct,
// and the value is its replaced tag name for later comparison to improve performance.
var (
tagMap = make(map[string]string)
priorityTagArray []string
)
if priorityTag != "" {
priorityTagArray = append(utils.SplitAndTrim(priorityTag, ","), StructTagPriority...)
} else {
priorityTagArray = StructTagPriority
}
tagToNameMap, err := structs.TagMapName(pointerElemReflectValue, priorityTagArray)
if err != nil {
return err
}
for tagName, attributeName := range tagToNameMap {
// If there's something else in the tag string,
// it uses the first part which is split using char ','.
// Eg:
// orm:"id, priority"
// orm:"name, with:uid=id"
tagMap[attributeName] = utils.RemoveSymbols(strings.Split(tagName, ",")[0])
}
var (
attrName string
checkName string
)
for mapK, mapV := range paramsMap {
attrName = ""
// It firstly checks the passed mapping rules.
if len(mapping) > 0 {
if passedAttrKey, ok := mapping[mapK]; ok {
attrName = passedAttrKey
}
}
// It secondly checks the predefined tags and matching rules.
if attrName == "" {
checkName = utils.RemoveSymbols(mapK)
// Loop to find the matched attribute name with or without
// string cases and chars like '-'/'_'/'.'/' '.
// Matching the parameters to struct tag names.
// The `tagV` is the attribute name of the struct.
for attrKey, cmpKey := range tagMap {
if strings.EqualFold(checkName, cmpKey) {
attrName = attrKey
break
}
}
// Matching the parameters to struct attributes.
if attrName == "" {
for attrKey, cmpKey := range attrMap {
// Eg:
// UserName eq user_name
// User-Name eq username
// username eq userName
// etc.
if strings.EqualFold(checkName, cmpKey) {
attrName = attrKey
break
}
}
}
}
// No matching, it gives up this attribute converting.
if attrName == "" {
continue
}
// If the attribute name is already checked converting, then skip it.
if _, ok := doneMap[attrName]; ok {
continue
}
// Mark it done.
doneMap[attrName] = struct{}{}
if err := bindVarToStructAttr(pointerElemReflectValue, attrName, mapV, mapping, priorityTag); err != nil {
return err
}
}
return nil
}
// bindVarToStructAttr sets value to struct object attribute by name.
func bindVarToStructAttr(elem reflect.Value, name string, value interface{}, mapping map[string]string, priorityTag string) (err error) {
structFieldValue := elem.FieldByName(name)
if !structFieldValue.IsValid() {
return nil
}
// CanSet checks whether attribute is public accessible.
if !structFieldValue.CanSet() {
return nil
}
defer func() {
if e := recover(); e != nil {
if err = bindVarToReflectValue(structFieldValue, value, mapping, priorityTag); err != nil {
err = gerror.Wrapf(err, `error binding value to attribute "%s"`, name)
}
}
}()
// Directly converting.
if empty.IsNil(value) {
structFieldValue.Set(reflect.Zero(structFieldValue.Type()))
} else {
structFieldValue.Set(reflect.ValueOf(Convert(value, structFieldValue.Type().String())))
}
return nil
}
// bindVarToReflectValueWithInterfaceCheck does binding using common interfaces checks.
func bindVarToReflectValueWithInterfaceCheck(reflectValue reflect.Value, value interface{}) (err error, ok bool) {
var pointer interface{}
if reflectValue.Kind() != reflect.Ptr && reflectValue.CanAddr() {
reflectValueAddr := reflectValue.Addr()
if reflectValueAddr.IsNil() || !reflectValueAddr.IsValid() {
return nil, false
}
// Not a pointer, but can token address, that makes it can be unmarshalled.
pointer = reflectValue.Addr().Interface()
} else {
if reflectValue.IsNil() || !reflectValue.IsValid() {
return nil, false
}
pointer = reflectValue.Interface()
}
if v, ok := pointer.(apiUnmarshalValue); ok {
return v.UnmarshalValue(value), ok
}
if v, ok := pointer.(apiUnmarshalText); ok {
if s, ok := value.(string); ok {
return v.UnmarshalText([]byte(s)), ok
}
if b, ok := value.([]byte); ok {
return v.UnmarshalText(b), ok
}
}
if v, ok := pointer.(apiSet); ok {
v.Set(value)
return nil, ok
}
return nil, false
}
// bindVarToReflectValue sets `value` to reflect value object `structFieldValue`.
func bindVarToReflectValue(structFieldValue reflect.Value, value interface{}, mapping map[string]string, priorityTag string) (err error) {
if err, ok := bindVarToReflectValueWithInterfaceCheck(structFieldValue, value); ok {
return err
}
kind := structFieldValue.Kind()
// Converting using interface, for some kinds.
switch kind {
case reflect.Slice, reflect.Array, reflect.Ptr, reflect.Interface:
if !structFieldValue.IsNil() {
if v, ok := structFieldValue.Interface().(apiSet); ok {
v.Set(value)
return nil
}
}
}
// Converting by kind.
switch kind {
case reflect.Struct:
// Recursively converting for struct attribute.
if err := doStruct(value, structFieldValue, nil, ""); err != nil {
// Note there's reflect conversion mechanism here.
structFieldValue.Set(reflect.ValueOf(value).Convert(structFieldValue.Type()))
}
// Note that the slice element might be type of struct,
// so it uses Struct function doing the converting internally.
case reflect.Slice, reflect.Array:
a := reflect.Value{}
v := reflect.ValueOf(value)
if v.Kind() == reflect.Slice || v.Kind() == reflect.Array {
a = reflect.MakeSlice(structFieldValue.Type(), v.Len(), v.Len())
if v.Len() > 0 {
t := a.Index(0).Type()
for i := 0; i < v.Len(); i++ {
if t.Kind() == reflect.Ptr {
e := reflect.New(t.Elem()).Elem()
if err := doStruct(v.Index(i).Interface(), e, nil, ""); err != nil {
// Note there's reflect conversion mechanism here.
e.Set(reflect.ValueOf(v.Index(i).Interface()).Convert(t))
}
a.Index(i).Set(e.Addr())
} else {
e := reflect.New(t).Elem()
if err := doStruct(v.Index(i).Interface(), e, nil, ""); err != nil {
// Note there's reflect conversion mechanism here.
e.Set(reflect.ValueOf(v.Index(i).Interface()).Convert(t))
}
a.Index(i).Set(e)
}
}
}
} else {
a = reflect.MakeSlice(structFieldValue.Type(), 1, 1)
t := a.Index(0).Type()
if t.Kind() == reflect.Ptr {
e := reflect.New(t.Elem()).Elem()
if err := doStruct(value, e, nil, ""); err != nil {
// Note there's reflect conversion mechanism here.
e.Set(reflect.ValueOf(value).Convert(t))
}
a.Index(0).Set(e.Addr())
} else {
e := reflect.New(t).Elem()
if err := doStruct(value, e, nil, ""); err != nil {
// Note there's reflect conversion mechanism here.
e.Set(reflect.ValueOf(value).Convert(t))
}
a.Index(0).Set(e)
}
}
structFieldValue.Set(a)
case reflect.Ptr:
item := reflect.New(structFieldValue.Type().Elem())
if err, ok := bindVarToReflectValueWithInterfaceCheck(item, value); ok {
structFieldValue.Set(item)
return err
}
elem := item.Elem()
if err = bindVarToReflectValue(elem, value, mapping, priorityTag); err == nil {
structFieldValue.Set(elem.Addr())
}
// It mainly and specially handles the interface of nil value.
case reflect.Interface:
if value == nil {
// Specially.
structFieldValue.Set(reflect.ValueOf((*interface{})(nil)))
} else {
// Note there's reflect conversion mechanism here.
structFieldValue.Set(reflect.ValueOf(value).Convert(structFieldValue.Type()))
}
default:
defer func() {
if e := recover(); e != nil {
err = gerror.New(
fmt.Sprintf(`cannot convert value "%+v" to type "%s"`,
value,
structFieldValue.Type().String(),
),
)
}
}()
// It here uses reflect converting `value` to type of the attribute and assigns
// the result value to the attribute. It might fail and panic if the usual Go
// conversion rules do not allow conversion.
structFieldValue.Set(reflect.ValueOf(value).Convert(structFieldValue.Type()))
}
return nil
}