262 lines
7.4 KiB
Go
262 lines
7.4 KiB
Go
package echo
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import (
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"encoding/json"
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"encoding/xml"
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"errors"
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"fmt"
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"net/http"
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"reflect"
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"strconv"
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"strings"
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)
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type (
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// Binder is the interface that wraps the Bind method.
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Binder interface {
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Bind(i interface{}, c Context) error
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}
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// DefaultBinder is the default implementation of the Binder interface.
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DefaultBinder struct{}
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// BindUnmarshaler is the interface used to wrap the UnmarshalParam method.
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BindUnmarshaler interface {
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// UnmarshalParam decodes and assigns a value from an form or query param.
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UnmarshalParam(param string) error
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}
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)
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// Bind implements the `Binder#Bind` function.
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func (b *DefaultBinder) Bind(i interface{}, c Context) (err error) {
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req := c.Request()
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if req.ContentLength == 0 {
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if req.Method == GET || req.Method == DELETE {
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if err = b.bindData(i, c.QueryParams(), "query"); err != nil {
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return NewHTTPError(http.StatusBadRequest, err.Error())
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}
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return
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}
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return NewHTTPError(http.StatusBadRequest, "Request body can't be empty")
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}
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ctype := req.Header.Get(HeaderContentType)
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switch {
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case strings.HasPrefix(ctype, MIMEApplicationJSON):
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if err = json.NewDecoder(req.Body).Decode(i); err != nil {
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if ute, ok := err.(*json.UnmarshalTypeError); ok {
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return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Unmarshal type error: expected=%v, got=%v, offset=%v", ute.Type, ute.Value, ute.Offset))
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} else if se, ok := err.(*json.SyntaxError); ok {
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return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Syntax error: offset=%v, error=%v", se.Offset, se.Error()))
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} else {
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return NewHTTPError(http.StatusBadRequest, err.Error())
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}
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}
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case strings.HasPrefix(ctype, MIMEApplicationXML), strings.HasPrefix(ctype, MIMETextXML):
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if err = xml.NewDecoder(req.Body).Decode(i); err != nil {
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if ute, ok := err.(*xml.UnsupportedTypeError); ok {
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return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Unsupported type error: type=%v, error=%v", ute.Type, ute.Error()))
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} else if se, ok := err.(*xml.SyntaxError); ok {
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return NewHTTPError(http.StatusBadRequest, fmt.Sprintf("Syntax error: line=%v, error=%v", se.Line, se.Error()))
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} else {
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return NewHTTPError(http.StatusBadRequest, err.Error())
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}
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}
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case strings.HasPrefix(ctype, MIMEApplicationForm), strings.HasPrefix(ctype, MIMEMultipartForm):
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params, err := c.FormParams()
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if err != nil {
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return NewHTTPError(http.StatusBadRequest, err.Error())
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}
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if err = b.bindData(i, params, "form"); err != nil {
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return NewHTTPError(http.StatusBadRequest, err.Error())
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}
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default:
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return ErrUnsupportedMediaType
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}
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return
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}
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func (b *DefaultBinder) bindData(ptr interface{}, data map[string][]string, tag string) error {
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typ := reflect.TypeOf(ptr).Elem()
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val := reflect.ValueOf(ptr).Elem()
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if typ.Kind() != reflect.Struct {
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return errors.New("Binding element must be a struct")
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}
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for i := 0; i < typ.NumField(); i++ {
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typeField := typ.Field(i)
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structField := val.Field(i)
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if !structField.CanSet() {
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continue
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}
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structFieldKind := structField.Kind()
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inputFieldName := typeField.Tag.Get(tag)
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if inputFieldName == "" {
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inputFieldName = typeField.Name
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// If tag is nil, we inspect if the field is a struct.
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if _, ok := bindUnmarshaler(structField); !ok && structFieldKind == reflect.Struct {
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err := b.bindData(structField.Addr().Interface(), data, tag)
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if err != nil {
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return err
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}
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continue
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}
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}
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inputValue, exists := data[inputFieldName]
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if !exists {
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continue
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}
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// Call this first, in case we're dealing with an alias to an array type
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if ok, err := unmarshalField(typeField.Type.Kind(), inputValue[0], structField); ok {
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if err != nil {
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return err
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}
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continue
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}
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numElems := len(inputValue)
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if structFieldKind == reflect.Slice && numElems > 0 {
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sliceOf := structField.Type().Elem().Kind()
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slice := reflect.MakeSlice(structField.Type(), numElems, numElems)
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for j := 0; j < numElems; j++ {
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if err := setWithProperType(sliceOf, inputValue[j], slice.Index(j)); err != nil {
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return err
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}
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}
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val.Field(i).Set(slice)
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} else {
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if err := setWithProperType(typeField.Type.Kind(), inputValue[0], structField); err != nil {
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return err
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}
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}
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}
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return nil
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}
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func setWithProperType(valueKind reflect.Kind, val string, structField reflect.Value) error {
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// But also call it here, in case we're dealing with an array of BindUnmarshalers
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if ok, err := unmarshalField(valueKind, val, structField); ok {
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return err
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}
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switch valueKind {
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case reflect.Ptr:
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return setWithProperType(structField.Elem().Kind(), val, structField.Elem())
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case reflect.Int:
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return setIntField(val, 0, structField)
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case reflect.Int8:
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return setIntField(val, 8, structField)
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case reflect.Int16:
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return setIntField(val, 16, structField)
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case reflect.Int32:
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return setIntField(val, 32, structField)
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case reflect.Int64:
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return setIntField(val, 64, structField)
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case reflect.Uint:
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return setUintField(val, 0, structField)
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case reflect.Uint8:
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return setUintField(val, 8, structField)
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case reflect.Uint16:
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return setUintField(val, 16, structField)
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case reflect.Uint32:
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return setUintField(val, 32, structField)
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case reflect.Uint64:
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return setUintField(val, 64, structField)
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case reflect.Bool:
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return setBoolField(val, structField)
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case reflect.Float32:
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return setFloatField(val, 32, structField)
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case reflect.Float64:
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return setFloatField(val, 64, structField)
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case reflect.String:
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structField.SetString(val)
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default:
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return errors.New("unknown type")
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}
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return nil
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}
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func unmarshalField(valueKind reflect.Kind, val string, field reflect.Value) (bool, error) {
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switch valueKind {
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case reflect.Ptr:
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return unmarshalFieldPtr(val, field)
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default:
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return unmarshalFieldNonPtr(val, field)
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}
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}
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// bindUnmarshaler attempts to unmarshal a reflect.Value into a BindUnmarshaler
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func bindUnmarshaler(field reflect.Value) (BindUnmarshaler, bool) {
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ptr := reflect.New(field.Type())
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if ptr.CanInterface() {
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iface := ptr.Interface()
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if unmarshaler, ok := iface.(BindUnmarshaler); ok {
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return unmarshaler, ok
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}
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}
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return nil, false
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}
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func unmarshalFieldNonPtr(value string, field reflect.Value) (bool, error) {
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if unmarshaler, ok := bindUnmarshaler(field); ok {
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err := unmarshaler.UnmarshalParam(value)
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field.Set(reflect.ValueOf(unmarshaler).Elem())
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return true, err
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}
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return false, nil
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}
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func unmarshalFieldPtr(value string, field reflect.Value) (bool, error) {
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if field.IsNil() {
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// Initialize the pointer to a nil value
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field.Set(reflect.New(field.Type().Elem()))
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}
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return unmarshalFieldNonPtr(value, field.Elem())
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}
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func setIntField(value string, bitSize int, field reflect.Value) error {
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if value == "" {
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value = "0"
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}
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intVal, err := strconv.ParseInt(value, 10, bitSize)
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if err == nil {
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field.SetInt(intVal)
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}
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return err
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}
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func setUintField(value string, bitSize int, field reflect.Value) error {
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if value == "" {
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value = "0"
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}
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uintVal, err := strconv.ParseUint(value, 10, bitSize)
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if err == nil {
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field.SetUint(uintVal)
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}
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return err
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}
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func setBoolField(value string, field reflect.Value) error {
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if value == "" {
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value = "false"
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}
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boolVal, err := strconv.ParseBool(value)
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if err == nil {
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field.SetBool(boolVal)
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}
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return err
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}
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func setFloatField(value string, bitSize int, field reflect.Value) error {
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if value == "" {
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value = "0.0"
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}
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floatVal, err := strconv.ParseFloat(value, bitSize)
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if err == nil {
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field.SetFloat(floatVal)
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}
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return err
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}
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