forked from ebhomengo/niki
532 lines
13 KiB
Go
532 lines
13 KiB
Go
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// Copyright 2013 sigu-399 ( https://github.com/sigu-399 )
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// author sigu-399
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// author-github https://github.com/sigu-399
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// author-mail sigu.399@gmail.com
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//
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// repository-name jsonpointer
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// repository-desc An implementation of JSON Pointer - Go language
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//
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// description Main and unique file.
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//
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// created 25-02-2013
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package jsonpointer
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import (
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"encoding/json"
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"errors"
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"fmt"
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"reflect"
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"strconv"
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"strings"
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"github.com/go-openapi/swag"
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)
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const (
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emptyPointer = ``
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pointerSeparator = `/`
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invalidStart = `JSON pointer must be empty or start with a "` + pointerSeparator
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notFound = `Can't find the pointer in the document`
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)
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var jsonPointableType = reflect.TypeOf(new(JSONPointable)).Elem()
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var jsonSetableType = reflect.TypeOf(new(JSONSetable)).Elem()
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// JSONPointable is an interface for structs to implement when they need to customize the
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// json pointer process
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type JSONPointable interface {
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JSONLookup(string) (any, error)
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}
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// JSONSetable is an interface for structs to implement when they need to customize the
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// json pointer process
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type JSONSetable interface {
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JSONSet(string, any) error
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}
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// New creates a new json pointer for the given string
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func New(jsonPointerString string) (Pointer, error) {
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var p Pointer
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err := p.parse(jsonPointerString)
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return p, err
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}
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// Pointer the json pointer reprsentation
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type Pointer struct {
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referenceTokens []string
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}
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// "Constructor", parses the given string JSON pointer
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func (p *Pointer) parse(jsonPointerString string) error {
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var err error
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if jsonPointerString != emptyPointer {
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if !strings.HasPrefix(jsonPointerString, pointerSeparator) {
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err = errors.New(invalidStart)
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} else {
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referenceTokens := strings.Split(jsonPointerString, pointerSeparator)
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p.referenceTokens = append(p.referenceTokens, referenceTokens[1:]...)
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}
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}
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return err
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}
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// Get uses the pointer to retrieve a value from a JSON document
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func (p *Pointer) Get(document any) (any, reflect.Kind, error) {
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return p.get(document, swag.DefaultJSONNameProvider)
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}
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// Set uses the pointer to set a value from a JSON document
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func (p *Pointer) Set(document any, value any) (any, error) {
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return document, p.set(document, value, swag.DefaultJSONNameProvider)
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}
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// GetForToken gets a value for a json pointer token 1 level deep
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func GetForToken(document any, decodedToken string) (any, reflect.Kind, error) {
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return getSingleImpl(document, decodedToken, swag.DefaultJSONNameProvider)
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}
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// SetForToken gets a value for a json pointer token 1 level deep
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func SetForToken(document any, decodedToken string, value any) (any, error) {
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return document, setSingleImpl(document, value, decodedToken, swag.DefaultJSONNameProvider)
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}
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func isNil(input any) bool {
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if input == nil {
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return true
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}
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kind := reflect.TypeOf(input).Kind()
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switch kind { //nolint:exhaustive
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case reflect.Ptr, reflect.Map, reflect.Slice, reflect.Chan:
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return reflect.ValueOf(input).IsNil()
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default:
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return false
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}
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}
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func getSingleImpl(node any, decodedToken string, nameProvider *swag.NameProvider) (any, reflect.Kind, error) {
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rValue := reflect.Indirect(reflect.ValueOf(node))
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kind := rValue.Kind()
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if isNil(node) {
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return nil, kind, fmt.Errorf("nil value has not field %q", decodedToken)
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}
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switch typed := node.(type) {
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case JSONPointable:
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r, err := typed.JSONLookup(decodedToken)
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if err != nil {
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return nil, kind, err
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}
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return r, kind, nil
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case *any: // case of a pointer to interface, that is not resolved by reflect.Indirect
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return getSingleImpl(*typed, decodedToken, nameProvider)
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}
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switch kind { //nolint:exhaustive
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case reflect.Struct:
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nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken)
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if !ok {
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return nil, kind, fmt.Errorf("object has no field %q", decodedToken)
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}
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fld := rValue.FieldByName(nm)
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return fld.Interface(), kind, nil
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case reflect.Map:
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kv := reflect.ValueOf(decodedToken)
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mv := rValue.MapIndex(kv)
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if mv.IsValid() {
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return mv.Interface(), kind, nil
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}
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return nil, kind, fmt.Errorf("object has no key %q", decodedToken)
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case reflect.Slice:
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tokenIndex, err := strconv.Atoi(decodedToken)
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if err != nil {
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return nil, kind, err
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}
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sLength := rValue.Len()
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if tokenIndex < 0 || tokenIndex >= sLength {
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return nil, kind, fmt.Errorf("index out of bounds array[0,%d] index '%d'", sLength-1, tokenIndex)
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}
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elem := rValue.Index(tokenIndex)
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return elem.Interface(), kind, nil
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default:
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return nil, kind, fmt.Errorf("invalid token reference %q", decodedToken)
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}
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}
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func setSingleImpl(node, data any, decodedToken string, nameProvider *swag.NameProvider) error {
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rValue := reflect.Indirect(reflect.ValueOf(node))
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if ns, ok := node.(JSONSetable); ok { // pointer impl
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return ns.JSONSet(decodedToken, data)
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}
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if rValue.Type().Implements(jsonSetableType) {
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return node.(JSONSetable).JSONSet(decodedToken, data)
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}
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switch rValue.Kind() { //nolint:exhaustive
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case reflect.Struct:
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nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken)
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if !ok {
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return fmt.Errorf("object has no field %q", decodedToken)
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}
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fld := rValue.FieldByName(nm)
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if fld.IsValid() {
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fld.Set(reflect.ValueOf(data))
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}
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return nil
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case reflect.Map:
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kv := reflect.ValueOf(decodedToken)
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rValue.SetMapIndex(kv, reflect.ValueOf(data))
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return nil
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case reflect.Slice:
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tokenIndex, err := strconv.Atoi(decodedToken)
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if err != nil {
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return err
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}
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sLength := rValue.Len()
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if tokenIndex < 0 || tokenIndex >= sLength {
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return fmt.Errorf("index out of bounds array[0,%d] index '%d'", sLength, tokenIndex)
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}
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elem := rValue.Index(tokenIndex)
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if !elem.CanSet() {
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return fmt.Errorf("can't set slice index %s to %v", decodedToken, data)
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}
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elem.Set(reflect.ValueOf(data))
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return nil
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default:
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return fmt.Errorf("invalid token reference %q", decodedToken)
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}
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}
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func (p *Pointer) get(node any, nameProvider *swag.NameProvider) (any, reflect.Kind, error) {
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if nameProvider == nil {
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nameProvider = swag.DefaultJSONNameProvider
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}
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kind := reflect.Invalid
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// Full document when empty
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if len(p.referenceTokens) == 0 {
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return node, kind, nil
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}
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for _, token := range p.referenceTokens {
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decodedToken := Unescape(token)
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r, knd, err := getSingleImpl(node, decodedToken, nameProvider)
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if err != nil {
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return nil, knd, err
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}
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node = r
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}
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rValue := reflect.ValueOf(node)
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kind = rValue.Kind()
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return node, kind, nil
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}
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func (p *Pointer) set(node, data any, nameProvider *swag.NameProvider) error {
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knd := reflect.ValueOf(node).Kind()
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if knd != reflect.Ptr && knd != reflect.Struct && knd != reflect.Map && knd != reflect.Slice && knd != reflect.Array {
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return errors.New("only structs, pointers, maps and slices are supported for setting values")
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}
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if nameProvider == nil {
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nameProvider = swag.DefaultJSONNameProvider
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}
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// Full document when empty
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if len(p.referenceTokens) == 0 {
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return nil
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}
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lastI := len(p.referenceTokens) - 1
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for i, token := range p.referenceTokens {
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isLastToken := i == lastI
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decodedToken := Unescape(token)
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if isLastToken {
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return setSingleImpl(node, data, decodedToken, nameProvider)
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}
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rValue := reflect.Indirect(reflect.ValueOf(node))
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kind := rValue.Kind()
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if rValue.Type().Implements(jsonPointableType) {
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r, err := node.(JSONPointable).JSONLookup(decodedToken)
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if err != nil {
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return err
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}
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fld := reflect.ValueOf(r)
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if fld.CanAddr() && fld.Kind() != reflect.Interface && fld.Kind() != reflect.Map && fld.Kind() != reflect.Slice && fld.Kind() != reflect.Ptr {
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node = fld.Addr().Interface()
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continue
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}
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node = r
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continue
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}
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switch kind { //nolint:exhaustive
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case reflect.Struct:
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nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken)
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if !ok {
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return fmt.Errorf("object has no field %q", decodedToken)
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}
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fld := rValue.FieldByName(nm)
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if fld.CanAddr() && fld.Kind() != reflect.Interface && fld.Kind() != reflect.Map && fld.Kind() != reflect.Slice && fld.Kind() != reflect.Ptr {
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node = fld.Addr().Interface()
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continue
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}
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node = fld.Interface()
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case reflect.Map:
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kv := reflect.ValueOf(decodedToken)
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mv := rValue.MapIndex(kv)
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if !mv.IsValid() {
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return fmt.Errorf("object has no key %q", decodedToken)
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}
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if mv.CanAddr() && mv.Kind() != reflect.Interface && mv.Kind() != reflect.Map && mv.Kind() != reflect.Slice && mv.Kind() != reflect.Ptr {
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node = mv.Addr().Interface()
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continue
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}
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node = mv.Interface()
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case reflect.Slice:
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tokenIndex, err := strconv.Atoi(decodedToken)
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if err != nil {
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return err
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}
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sLength := rValue.Len()
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if tokenIndex < 0 || tokenIndex >= sLength {
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return fmt.Errorf("index out of bounds array[0,%d] index '%d'", sLength, tokenIndex)
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}
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elem := rValue.Index(tokenIndex)
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if elem.CanAddr() && elem.Kind() != reflect.Interface && elem.Kind() != reflect.Map && elem.Kind() != reflect.Slice && elem.Kind() != reflect.Ptr {
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node = elem.Addr().Interface()
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continue
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}
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node = elem.Interface()
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default:
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return fmt.Errorf("invalid token reference %q", decodedToken)
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}
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}
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return nil
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}
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// DecodedTokens returns the decoded tokens
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func (p *Pointer) DecodedTokens() []string {
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result := make([]string, 0, len(p.referenceTokens))
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for _, t := range p.referenceTokens {
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result = append(result, Unescape(t))
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}
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return result
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}
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// IsEmpty returns true if this is an empty json pointer
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// this indicates that it points to the root document
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func (p *Pointer) IsEmpty() bool {
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return len(p.referenceTokens) == 0
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}
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// Pointer to string representation function
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func (p *Pointer) String() string {
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if len(p.referenceTokens) == 0 {
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return emptyPointer
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}
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pointerString := pointerSeparator + strings.Join(p.referenceTokens, pointerSeparator)
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return pointerString
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}
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func (p *Pointer) Offset(document string) (int64, error) {
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dec := json.NewDecoder(strings.NewReader(document))
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var offset int64
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for _, ttk := range p.DecodedTokens() {
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tk, err := dec.Token()
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if err != nil {
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return 0, err
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}
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|
|
switch tk := tk.(type) {
|
||
|
|
case json.Delim:
|
||
|
|
switch tk {
|
||
|
|
case '{':
|
||
|
|
offset, err = offsetSingleObject(dec, ttk)
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
case '[':
|
||
|
|
offset, err = offsetSingleArray(dec, ttk)
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
default:
|
||
|
|
return 0, fmt.Errorf("invalid token %#v", tk)
|
||
|
|
}
|
||
|
|
default:
|
||
|
|
return 0, fmt.Errorf("invalid token %#v", tk)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return offset, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func offsetSingleObject(dec *json.Decoder, decodedToken string) (int64, error) {
|
||
|
|
for dec.More() {
|
||
|
|
offset := dec.InputOffset()
|
||
|
|
tk, err := dec.Token()
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
switch tk := tk.(type) {
|
||
|
|
case json.Delim:
|
||
|
|
switch tk {
|
||
|
|
case '{':
|
||
|
|
if err = drainSingle(dec); err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
case '[':
|
||
|
|
if err = drainSingle(dec); err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
}
|
||
|
|
case string:
|
||
|
|
if tk == decodedToken {
|
||
|
|
return offset, nil
|
||
|
|
}
|
||
|
|
default:
|
||
|
|
return 0, fmt.Errorf("invalid token %#v", tk)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return 0, fmt.Errorf("token reference %q not found", decodedToken)
|
||
|
|
}
|
||
|
|
|
||
|
|
func offsetSingleArray(dec *json.Decoder, decodedToken string) (int64, error) {
|
||
|
|
idx, err := strconv.Atoi(decodedToken)
|
||
|
|
if err != nil {
|
||
|
|
return 0, fmt.Errorf("token reference %q is not a number: %v", decodedToken, err)
|
||
|
|
}
|
||
|
|
var i int
|
||
|
|
for i = 0; i < idx && dec.More(); i++ {
|
||
|
|
tk, err := dec.Token()
|
||
|
|
if err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
|
||
|
|
if delim, isDelim := tk.(json.Delim); isDelim {
|
||
|
|
switch delim {
|
||
|
|
case '{':
|
||
|
|
if err = drainSingle(dec); err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
case '[':
|
||
|
|
if err = drainSingle(dec); err != nil {
|
||
|
|
return 0, err
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if !dec.More() {
|
||
|
|
return 0, fmt.Errorf("token reference %q not found", decodedToken)
|
||
|
|
}
|
||
|
|
return dec.InputOffset(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// drainSingle drains a single level of object or array.
|
||
|
|
// The decoder has to guarantee the beginning delim (i.e. '{' or '[') has been consumed.
|
||
|
|
func drainSingle(dec *json.Decoder) error {
|
||
|
|
for dec.More() {
|
||
|
|
tk, err := dec.Token()
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if delim, isDelim := tk.(json.Delim); isDelim {
|
||
|
|
switch delim {
|
||
|
|
case '{':
|
||
|
|
if err = drainSingle(dec); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
case '[':
|
||
|
|
if err = drainSingle(dec); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Consumes the ending delim
|
||
|
|
if _, err := dec.Token(); err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Specific JSON pointer encoding here
|
||
|
|
// ~0 => ~
|
||
|
|
// ~1 => /
|
||
|
|
// ... and vice versa
|
||
|
|
|
||
|
|
const (
|
||
|
|
encRefTok0 = `~0`
|
||
|
|
encRefTok1 = `~1`
|
||
|
|
decRefTok0 = `~`
|
||
|
|
decRefTok1 = `/`
|
||
|
|
)
|
||
|
|
|
||
|
|
// Unescape unescapes a json pointer reference token string to the original representation
|
||
|
|
func Unescape(token string) string {
|
||
|
|
step1 := strings.ReplaceAll(token, encRefTok1, decRefTok1)
|
||
|
|
step2 := strings.ReplaceAll(step1, encRefTok0, decRefTok0)
|
||
|
|
return step2
|
||
|
|
}
|
||
|
|
|
||
|
|
// Escape escapes a pointer reference token string
|
||
|
|
func Escape(token string) string {
|
||
|
|
step1 := strings.ReplaceAll(token, decRefTok0, encRefTok0)
|
||
|
|
step2 := strings.ReplaceAll(step1, decRefTok1, encRefTok1)
|
||
|
|
return step2
|
||
|
|
}
|