Matthias Andreas Benkard | 832a54e | 2019-01-29 09:27:38 +0100 | [diff] [blame^] | 1 | // Copyright 2013 sigu-399 ( https://github.com/sigu-399 ) |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | // author sigu-399 |
| 16 | // author-github https://github.com/sigu-399 |
| 17 | // author-mail sigu.399@gmail.com |
| 18 | // |
| 19 | // repository-name jsonpointer |
| 20 | // repository-desc An implementation of JSON Pointer - Go language |
| 21 | // |
| 22 | // description Main and unique file. |
| 23 | // |
| 24 | // created 25-02-2013 |
| 25 | |
| 26 | package jsonpointer |
| 27 | |
| 28 | import ( |
| 29 | "errors" |
| 30 | "fmt" |
| 31 | "reflect" |
| 32 | "strconv" |
| 33 | "strings" |
| 34 | |
| 35 | "github.com/go-openapi/swag" |
| 36 | ) |
| 37 | |
| 38 | const ( |
| 39 | emptyPointer = `` |
| 40 | pointerSeparator = `/` |
| 41 | |
| 42 | invalidStart = `JSON pointer must be empty or start with a "` + pointerSeparator |
| 43 | ) |
| 44 | |
| 45 | var jsonPointableType = reflect.TypeOf(new(JSONPointable)).Elem() |
| 46 | var jsonSetableType = reflect.TypeOf(new(JSONSetable)).Elem() |
| 47 | |
| 48 | // JSONPointable is an interface for structs to implement when they need to customize the |
| 49 | // json pointer process |
| 50 | type JSONPointable interface { |
| 51 | JSONLookup(string) (interface{}, error) |
| 52 | } |
| 53 | |
| 54 | // JSONSetable is an interface for structs to implement when they need to customize the |
| 55 | // json pointer process |
| 56 | type JSONSetable interface { |
| 57 | JSONSet(string, interface{}) error |
| 58 | } |
| 59 | |
| 60 | // New creates a new json pointer for the given string |
| 61 | func New(jsonPointerString string) (Pointer, error) { |
| 62 | |
| 63 | var p Pointer |
| 64 | err := p.parse(jsonPointerString) |
| 65 | return p, err |
| 66 | |
| 67 | } |
| 68 | |
| 69 | // Pointer the json pointer reprsentation |
| 70 | type Pointer struct { |
| 71 | referenceTokens []string |
| 72 | } |
| 73 | |
| 74 | // "Constructor", parses the given string JSON pointer |
| 75 | func (p *Pointer) parse(jsonPointerString string) error { |
| 76 | |
| 77 | var err error |
| 78 | |
| 79 | if jsonPointerString != emptyPointer { |
| 80 | if !strings.HasPrefix(jsonPointerString, pointerSeparator) { |
| 81 | err = errors.New(invalidStart) |
| 82 | } else { |
| 83 | referenceTokens := strings.Split(jsonPointerString, pointerSeparator) |
| 84 | for _, referenceToken := range referenceTokens[1:] { |
| 85 | p.referenceTokens = append(p.referenceTokens, referenceToken) |
| 86 | } |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | return err |
| 91 | } |
| 92 | |
| 93 | // Get uses the pointer to retrieve a value from a JSON document |
| 94 | func (p *Pointer) Get(document interface{}) (interface{}, reflect.Kind, error) { |
| 95 | return p.get(document, swag.DefaultJSONNameProvider) |
| 96 | } |
| 97 | |
| 98 | // Set uses the pointer to set a value from a JSON document |
| 99 | func (p *Pointer) Set(document interface{}, value interface{}) (interface{}, error) { |
| 100 | return document, p.set(document, value, swag.DefaultJSONNameProvider) |
| 101 | } |
| 102 | |
| 103 | // GetForToken gets a value for a json pointer token 1 level deep |
| 104 | func GetForToken(document interface{}, decodedToken string) (interface{}, reflect.Kind, error) { |
| 105 | return getSingleImpl(document, decodedToken, swag.DefaultJSONNameProvider) |
| 106 | } |
| 107 | |
| 108 | // SetForToken gets a value for a json pointer token 1 level deep |
| 109 | func SetForToken(document interface{}, decodedToken string, value interface{}) (interface{}, error) { |
| 110 | return document, setSingleImpl(document, value, decodedToken, swag.DefaultJSONNameProvider) |
| 111 | } |
| 112 | |
| 113 | func getSingleImpl(node interface{}, decodedToken string, nameProvider *swag.NameProvider) (interface{}, reflect.Kind, error) { |
| 114 | rValue := reflect.Indirect(reflect.ValueOf(node)) |
| 115 | kind := rValue.Kind() |
| 116 | |
| 117 | switch kind { |
| 118 | |
| 119 | case reflect.Struct: |
| 120 | if rValue.Type().Implements(jsonPointableType) { |
| 121 | r, err := node.(JSONPointable).JSONLookup(decodedToken) |
| 122 | if err != nil { |
| 123 | return nil, kind, err |
| 124 | } |
| 125 | return r, kind, nil |
| 126 | } |
| 127 | nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken) |
| 128 | if !ok { |
| 129 | return nil, kind, fmt.Errorf("object has no field %q", decodedToken) |
| 130 | } |
| 131 | fld := rValue.FieldByName(nm) |
| 132 | return fld.Interface(), kind, nil |
| 133 | |
| 134 | case reflect.Map: |
| 135 | kv := reflect.ValueOf(decodedToken) |
| 136 | mv := rValue.MapIndex(kv) |
| 137 | |
| 138 | if mv.IsValid() && !swag.IsZero(mv) { |
| 139 | return mv.Interface(), kind, nil |
| 140 | } |
| 141 | return nil, kind, fmt.Errorf("object has no key %q", decodedToken) |
| 142 | |
| 143 | case reflect.Slice: |
| 144 | tokenIndex, err := strconv.Atoi(decodedToken) |
| 145 | if err != nil { |
| 146 | return nil, kind, err |
| 147 | } |
| 148 | sLength := rValue.Len() |
| 149 | if tokenIndex < 0 || tokenIndex >= sLength { |
| 150 | return nil, kind, fmt.Errorf("index out of bounds array[0,%d] index '%d'", sLength-1, tokenIndex) |
| 151 | } |
| 152 | |
| 153 | elem := rValue.Index(tokenIndex) |
| 154 | return elem.Interface(), kind, nil |
| 155 | |
| 156 | default: |
| 157 | return nil, kind, fmt.Errorf("invalid token reference %q", decodedToken) |
| 158 | } |
| 159 | |
| 160 | } |
| 161 | |
| 162 | func setSingleImpl(node, data interface{}, decodedToken string, nameProvider *swag.NameProvider) error { |
| 163 | rValue := reflect.Indirect(reflect.ValueOf(node)) |
| 164 | switch rValue.Kind() { |
| 165 | |
| 166 | case reflect.Struct: |
| 167 | if ns, ok := node.(JSONSetable); ok { // pointer impl |
| 168 | return ns.JSONSet(decodedToken, data) |
| 169 | } |
| 170 | |
| 171 | if rValue.Type().Implements(jsonSetableType) { |
| 172 | return node.(JSONSetable).JSONSet(decodedToken, data) |
| 173 | } |
| 174 | |
| 175 | nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken) |
| 176 | if !ok { |
| 177 | return fmt.Errorf("object has no field %q", decodedToken) |
| 178 | } |
| 179 | fld := rValue.FieldByName(nm) |
| 180 | if fld.IsValid() { |
| 181 | fld.Set(reflect.ValueOf(data)) |
| 182 | } |
| 183 | return nil |
| 184 | |
| 185 | case reflect.Map: |
| 186 | kv := reflect.ValueOf(decodedToken) |
| 187 | rValue.SetMapIndex(kv, reflect.ValueOf(data)) |
| 188 | return nil |
| 189 | |
| 190 | case reflect.Slice: |
| 191 | tokenIndex, err := strconv.Atoi(decodedToken) |
| 192 | if err != nil { |
| 193 | return err |
| 194 | } |
| 195 | sLength := rValue.Len() |
| 196 | if tokenIndex < 0 || tokenIndex >= sLength { |
| 197 | return fmt.Errorf("index out of bounds array[0,%d] index '%d'", sLength, tokenIndex) |
| 198 | } |
| 199 | |
| 200 | elem := rValue.Index(tokenIndex) |
| 201 | if !elem.CanSet() { |
| 202 | return fmt.Errorf("can't set slice index %s to %v", decodedToken, data) |
| 203 | } |
| 204 | elem.Set(reflect.ValueOf(data)) |
| 205 | return nil |
| 206 | |
| 207 | default: |
| 208 | return fmt.Errorf("invalid token reference %q", decodedToken) |
| 209 | } |
| 210 | |
| 211 | } |
| 212 | |
| 213 | func (p *Pointer) get(node interface{}, nameProvider *swag.NameProvider) (interface{}, reflect.Kind, error) { |
| 214 | |
| 215 | if nameProvider == nil { |
| 216 | nameProvider = swag.DefaultJSONNameProvider |
| 217 | } |
| 218 | |
| 219 | kind := reflect.Invalid |
| 220 | |
| 221 | // Full document when empty |
| 222 | if len(p.referenceTokens) == 0 { |
| 223 | return node, kind, nil |
| 224 | } |
| 225 | |
| 226 | for _, token := range p.referenceTokens { |
| 227 | |
| 228 | decodedToken := Unescape(token) |
| 229 | |
| 230 | r, knd, err := getSingleImpl(node, decodedToken, nameProvider) |
| 231 | if err != nil { |
| 232 | return nil, knd, err |
| 233 | } |
| 234 | node, kind = r, knd |
| 235 | |
| 236 | } |
| 237 | |
| 238 | rValue := reflect.ValueOf(node) |
| 239 | kind = rValue.Kind() |
| 240 | |
| 241 | return node, kind, nil |
| 242 | } |
| 243 | |
| 244 | func (p *Pointer) set(node, data interface{}, nameProvider *swag.NameProvider) error { |
| 245 | knd := reflect.ValueOf(node).Kind() |
| 246 | |
| 247 | if knd != reflect.Ptr && knd != reflect.Struct && knd != reflect.Map && knd != reflect.Slice && knd != reflect.Array { |
| 248 | return fmt.Errorf("only structs, pointers, maps and slices are supported for setting values") |
| 249 | } |
| 250 | |
| 251 | if nameProvider == nil { |
| 252 | nameProvider = swag.DefaultJSONNameProvider |
| 253 | } |
| 254 | |
| 255 | // Full document when empty |
| 256 | if len(p.referenceTokens) == 0 { |
| 257 | return nil |
| 258 | } |
| 259 | |
| 260 | lastI := len(p.referenceTokens) - 1 |
| 261 | for i, token := range p.referenceTokens { |
| 262 | isLastToken := i == lastI |
| 263 | decodedToken := Unescape(token) |
| 264 | |
| 265 | if isLastToken { |
| 266 | |
| 267 | return setSingleImpl(node, data, decodedToken, nameProvider) |
| 268 | } |
| 269 | |
| 270 | rValue := reflect.Indirect(reflect.ValueOf(node)) |
| 271 | kind := rValue.Kind() |
| 272 | |
| 273 | switch kind { |
| 274 | |
| 275 | case reflect.Struct: |
| 276 | if rValue.Type().Implements(jsonPointableType) { |
| 277 | r, err := node.(JSONPointable).JSONLookup(decodedToken) |
| 278 | if err != nil { |
| 279 | return err |
| 280 | } |
| 281 | fld := reflect.ValueOf(r) |
| 282 | if fld.CanAddr() && fld.Kind() != reflect.Interface && fld.Kind() != reflect.Map && fld.Kind() != reflect.Slice && fld.Kind() != reflect.Ptr { |
| 283 | node = fld.Addr().Interface() |
| 284 | continue |
| 285 | } |
| 286 | node = r |
| 287 | continue |
| 288 | } |
| 289 | nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken) |
| 290 | if !ok { |
| 291 | return fmt.Errorf("object has no field %q", decodedToken) |
| 292 | } |
| 293 | fld := rValue.FieldByName(nm) |
| 294 | if fld.CanAddr() && fld.Kind() != reflect.Interface && fld.Kind() != reflect.Map && fld.Kind() != reflect.Slice && fld.Kind() != reflect.Ptr { |
| 295 | node = fld.Addr().Interface() |
| 296 | continue |
| 297 | } |
| 298 | node = fld.Interface() |
| 299 | |
| 300 | case reflect.Map: |
| 301 | kv := reflect.ValueOf(decodedToken) |
| 302 | mv := rValue.MapIndex(kv) |
| 303 | |
| 304 | if !mv.IsValid() { |
| 305 | return fmt.Errorf("object has no key %q", decodedToken) |
| 306 | } |
| 307 | if mv.CanAddr() && mv.Kind() != reflect.Interface && mv.Kind() != reflect.Map && mv.Kind() != reflect.Slice && mv.Kind() != reflect.Ptr { |
| 308 | node = mv.Addr().Interface() |
| 309 | continue |
| 310 | } |
| 311 | node = mv.Interface() |
| 312 | |
| 313 | case reflect.Slice: |
| 314 | tokenIndex, err := strconv.Atoi(decodedToken) |
| 315 | if err != nil { |
| 316 | return err |
| 317 | } |
| 318 | sLength := rValue.Len() |
| 319 | if tokenIndex < 0 || tokenIndex >= sLength { |
| 320 | return fmt.Errorf("index out of bounds array[0,%d] index '%d'", sLength, tokenIndex) |
| 321 | } |
| 322 | |
| 323 | elem := rValue.Index(tokenIndex) |
| 324 | if elem.CanAddr() && elem.Kind() != reflect.Interface && elem.Kind() != reflect.Map && elem.Kind() != reflect.Slice && elem.Kind() != reflect.Ptr { |
| 325 | node = elem.Addr().Interface() |
| 326 | continue |
| 327 | } |
| 328 | node = elem.Interface() |
| 329 | |
| 330 | default: |
| 331 | return fmt.Errorf("invalid token reference %q", decodedToken) |
| 332 | } |
| 333 | |
| 334 | } |
| 335 | |
| 336 | return nil |
| 337 | } |
| 338 | |
| 339 | // DecodedTokens returns the decoded tokens |
| 340 | func (p *Pointer) DecodedTokens() []string { |
| 341 | result := make([]string, 0, len(p.referenceTokens)) |
| 342 | for _, t := range p.referenceTokens { |
| 343 | result = append(result, Unescape(t)) |
| 344 | } |
| 345 | return result |
| 346 | } |
| 347 | |
| 348 | // IsEmpty returns true if this is an empty json pointer |
| 349 | // this indicates that it points to the root document |
| 350 | func (p *Pointer) IsEmpty() bool { |
| 351 | return len(p.referenceTokens) == 0 |
| 352 | } |
| 353 | |
| 354 | // Pointer to string representation function |
| 355 | func (p *Pointer) String() string { |
| 356 | |
| 357 | if len(p.referenceTokens) == 0 { |
| 358 | return emptyPointer |
| 359 | } |
| 360 | |
| 361 | pointerString := pointerSeparator + strings.Join(p.referenceTokens, pointerSeparator) |
| 362 | |
| 363 | return pointerString |
| 364 | } |
| 365 | |
| 366 | // Specific JSON pointer encoding here |
| 367 | // ~0 => ~ |
| 368 | // ~1 => / |
| 369 | // ... and vice versa |
| 370 | |
| 371 | const ( |
| 372 | encRefTok0 = `~0` |
| 373 | encRefTok1 = `~1` |
| 374 | decRefTok0 = `~` |
| 375 | decRefTok1 = `/` |
| 376 | ) |
| 377 | |
| 378 | // Unescape unescapes a json pointer reference token string to the original representation |
| 379 | func Unescape(token string) string { |
| 380 | step1 := strings.Replace(token, encRefTok1, decRefTok1, -1) |
| 381 | step2 := strings.Replace(step1, encRefTok0, decRefTok0, -1) |
| 382 | return step2 |
| 383 | } |
| 384 | |
| 385 | // Escape escapes a pointer reference token string |
| 386 | func Escape(token string) string { |
| 387 | step1 := strings.Replace(token, decRefTok0, encRefTok0, -1) |
| 388 | step2 := strings.Replace(step1, decRefTok1, encRefTok1, -1) |
| 389 | return step2 |
| 390 | } |