Don Newton | 379ae25 | 2019-04-01 12:17:06 -0400 | [diff] [blame^] | 1 | // Copyright (C) MongoDB, Inc. 2017-present. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| 4 | // not use this file except in compliance with the License. You may obtain |
| 5 | // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| 6 | |
| 7 | package bsonrw |
| 8 | |
| 9 | import ( |
| 10 | "bytes" |
| 11 | "encoding/binary" |
| 12 | "errors" |
| 13 | "fmt" |
| 14 | "io" |
| 15 | "math" |
| 16 | "sync" |
| 17 | "unicode" |
| 18 | |
| 19 | "github.com/mongodb/mongo-go-driver/bson/bsontype" |
| 20 | "github.com/mongodb/mongo-go-driver/bson/primitive" |
| 21 | ) |
| 22 | |
| 23 | var _ ValueReader = (*valueReader)(nil) |
| 24 | |
| 25 | var vrPool = sync.Pool{ |
| 26 | New: func() interface{} { |
| 27 | return new(valueReader) |
| 28 | }, |
| 29 | } |
| 30 | |
| 31 | // BSONValueReaderPool is a pool for ValueReaders that read BSON. |
| 32 | type BSONValueReaderPool struct { |
| 33 | pool sync.Pool |
| 34 | } |
| 35 | |
| 36 | // NewBSONValueReaderPool instantiates a new BSONValueReaderPool. |
| 37 | func NewBSONValueReaderPool() *BSONValueReaderPool { |
| 38 | return &BSONValueReaderPool{ |
| 39 | pool: sync.Pool{ |
| 40 | New: func() interface{} { |
| 41 | return new(valueReader) |
| 42 | }, |
| 43 | }, |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | // Get retrieves a ValueReader from the pool and uses src as the underlying BSON. |
| 48 | func (bvrp *BSONValueReaderPool) Get(src []byte) ValueReader { |
| 49 | vr := bvrp.pool.Get().(*valueReader) |
| 50 | vr.reset(src) |
| 51 | return vr |
| 52 | } |
| 53 | |
| 54 | // Put inserts a ValueReader into the pool. If the ValueReader is not a BSON ValueReader nothing |
| 55 | // is inserted into the pool and ok will be false. |
| 56 | func (bvrp *BSONValueReaderPool) Put(vr ValueReader) (ok bool) { |
| 57 | bvr, ok := vr.(*valueReader) |
| 58 | if !ok { |
| 59 | return false |
| 60 | } |
| 61 | |
| 62 | bvr.reset(nil) |
| 63 | bvrp.pool.Put(bvr) |
| 64 | return true |
| 65 | } |
| 66 | |
| 67 | // ErrEOA is the error returned when the end of a BSON array has been reached. |
| 68 | var ErrEOA = errors.New("end of array") |
| 69 | |
| 70 | // ErrEOD is the error returned when the end of a BSON document has been reached. |
| 71 | var ErrEOD = errors.New("end of document") |
| 72 | |
| 73 | type vrState struct { |
| 74 | mode mode |
| 75 | vType bsontype.Type |
| 76 | end int64 |
| 77 | } |
| 78 | |
| 79 | // valueReader is for reading BSON values. |
| 80 | type valueReader struct { |
| 81 | offset int64 |
| 82 | d []byte |
| 83 | |
| 84 | stack []vrState |
| 85 | frame int64 |
| 86 | } |
| 87 | |
| 88 | // NewBSONDocumentReader returns a ValueReader using b for the underlying BSON |
| 89 | // representation. Parameter b must be a BSON Document. |
| 90 | // |
| 91 | // TODO(skriptble): There's a lack of symmetry between the reader and writer, since the reader takes |
| 92 | // a []byte while the writer takes an io.Writer. We should have two versions of each, one that takes |
| 93 | // a []byte and one that takes an io.Reader or io.Writer. The []byte version will need to return a |
| 94 | // thing that can return the finished []byte since it might be reallocated when appended to. |
| 95 | func NewBSONDocumentReader(b []byte) ValueReader { |
| 96 | return newValueReader(b) |
| 97 | } |
| 98 | |
| 99 | // NewBSONValueReader returns a ValueReader that starts in the Value mode instead of in top |
| 100 | // level document mode. This enables the creation of a ValueReader for a single BSON value. |
| 101 | func NewBSONValueReader(t bsontype.Type, val []byte) ValueReader { |
| 102 | stack := make([]vrState, 1, 5) |
| 103 | stack[0] = vrState{ |
| 104 | mode: mValue, |
| 105 | vType: t, |
| 106 | } |
| 107 | return &valueReader{ |
| 108 | d: val, |
| 109 | stack: stack, |
| 110 | } |
| 111 | } |
| 112 | |
| 113 | func newValueReader(b []byte) *valueReader { |
| 114 | stack := make([]vrState, 1, 5) |
| 115 | stack[0] = vrState{ |
| 116 | mode: mTopLevel, |
| 117 | } |
| 118 | return &valueReader{ |
| 119 | d: b, |
| 120 | stack: stack, |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | func (vr *valueReader) reset(b []byte) { |
| 125 | if vr.stack == nil { |
| 126 | vr.stack = make([]vrState, 1, 5) |
| 127 | } |
| 128 | vr.stack = vr.stack[:1] |
| 129 | vr.stack[0] = vrState{mode: mTopLevel} |
| 130 | vr.d = b |
| 131 | vr.offset = 0 |
| 132 | vr.frame = 0 |
| 133 | } |
| 134 | |
| 135 | func (vr *valueReader) advanceFrame() { |
| 136 | if vr.frame+1 >= int64(len(vr.stack)) { // We need to grow the stack |
| 137 | length := len(vr.stack) |
| 138 | if length+1 >= cap(vr.stack) { |
| 139 | // double it |
| 140 | buf := make([]vrState, 2*cap(vr.stack)+1) |
| 141 | copy(buf, vr.stack) |
| 142 | vr.stack = buf |
| 143 | } |
| 144 | vr.stack = vr.stack[:length+1] |
| 145 | } |
| 146 | vr.frame++ |
| 147 | |
| 148 | // Clean the stack |
| 149 | vr.stack[vr.frame].mode = 0 |
| 150 | vr.stack[vr.frame].vType = 0 |
| 151 | vr.stack[vr.frame].end = 0 |
| 152 | } |
| 153 | |
| 154 | func (vr *valueReader) pushDocument() error { |
| 155 | vr.advanceFrame() |
| 156 | |
| 157 | vr.stack[vr.frame].mode = mDocument |
| 158 | |
| 159 | size, err := vr.readLength() |
| 160 | if err != nil { |
| 161 | return err |
| 162 | } |
| 163 | vr.stack[vr.frame].end = int64(size) + vr.offset - 4 |
| 164 | |
| 165 | return nil |
| 166 | } |
| 167 | |
| 168 | func (vr *valueReader) pushArray() error { |
| 169 | vr.advanceFrame() |
| 170 | |
| 171 | vr.stack[vr.frame].mode = mArray |
| 172 | |
| 173 | size, err := vr.readLength() |
| 174 | if err != nil { |
| 175 | return err |
| 176 | } |
| 177 | vr.stack[vr.frame].end = int64(size) + vr.offset - 4 |
| 178 | |
| 179 | return nil |
| 180 | } |
| 181 | |
| 182 | func (vr *valueReader) pushElement(t bsontype.Type) { |
| 183 | vr.advanceFrame() |
| 184 | |
| 185 | vr.stack[vr.frame].mode = mElement |
| 186 | vr.stack[vr.frame].vType = t |
| 187 | } |
| 188 | |
| 189 | func (vr *valueReader) pushValue(t bsontype.Type) { |
| 190 | vr.advanceFrame() |
| 191 | |
| 192 | vr.stack[vr.frame].mode = mValue |
| 193 | vr.stack[vr.frame].vType = t |
| 194 | } |
| 195 | |
| 196 | func (vr *valueReader) pushCodeWithScope() (int64, error) { |
| 197 | vr.advanceFrame() |
| 198 | |
| 199 | vr.stack[vr.frame].mode = mCodeWithScope |
| 200 | |
| 201 | size, err := vr.readLength() |
| 202 | if err != nil { |
| 203 | return 0, err |
| 204 | } |
| 205 | vr.stack[vr.frame].end = int64(size) + vr.offset - 4 |
| 206 | |
| 207 | return int64(size), nil |
| 208 | } |
| 209 | |
| 210 | func (vr *valueReader) pop() { |
| 211 | switch vr.stack[vr.frame].mode { |
| 212 | case mElement, mValue: |
| 213 | vr.frame-- |
| 214 | case mDocument, mArray, mCodeWithScope: |
| 215 | vr.frame -= 2 // we pop twice to jump over the vrElement: vrDocument -> vrElement -> vrDocument/TopLevel/etc... |
| 216 | } |
| 217 | } |
| 218 | |
| 219 | func (vr *valueReader) invalidTransitionErr(destination mode, name string, modes []mode) error { |
| 220 | te := TransitionError{ |
| 221 | name: name, |
| 222 | current: vr.stack[vr.frame].mode, |
| 223 | destination: destination, |
| 224 | modes: modes, |
| 225 | action: "read", |
| 226 | } |
| 227 | if vr.frame != 0 { |
| 228 | te.parent = vr.stack[vr.frame-1].mode |
| 229 | } |
| 230 | return te |
| 231 | } |
| 232 | |
| 233 | func (vr *valueReader) typeError(t bsontype.Type) error { |
| 234 | return fmt.Errorf("positioned on %s, but attempted to read %s", vr.stack[vr.frame].vType, t) |
| 235 | } |
| 236 | |
| 237 | func (vr *valueReader) invalidDocumentLengthError() error { |
| 238 | return fmt.Errorf("document is invalid, end byte is at %d, but null byte found at %d", vr.stack[vr.frame].end, vr.offset) |
| 239 | } |
| 240 | |
| 241 | func (vr *valueReader) ensureElementValue(t bsontype.Type, destination mode, callerName string) error { |
| 242 | switch vr.stack[vr.frame].mode { |
| 243 | case mElement, mValue: |
| 244 | if vr.stack[vr.frame].vType != t { |
| 245 | return vr.typeError(t) |
| 246 | } |
| 247 | default: |
| 248 | return vr.invalidTransitionErr(destination, callerName, []mode{mElement, mValue}) |
| 249 | } |
| 250 | |
| 251 | return nil |
| 252 | } |
| 253 | |
| 254 | func (vr *valueReader) Type() bsontype.Type { |
| 255 | return vr.stack[vr.frame].vType |
| 256 | } |
| 257 | |
| 258 | func (vr *valueReader) nextElementLength() (int32, error) { |
| 259 | var length int32 |
| 260 | var err error |
| 261 | switch vr.stack[vr.frame].vType { |
| 262 | case bsontype.Array, bsontype.EmbeddedDocument, bsontype.CodeWithScope: |
| 263 | length, err = vr.peekLength() |
| 264 | case bsontype.Binary: |
| 265 | length, err = vr.peekLength() |
| 266 | length += 4 + 1 // binary length + subtype byte |
| 267 | case bsontype.Boolean: |
| 268 | length = 1 |
| 269 | case bsontype.DBPointer: |
| 270 | length, err = vr.peekLength() |
| 271 | length += 4 + 12 // string length + ObjectID length |
| 272 | case bsontype.DateTime, bsontype.Double, bsontype.Int64, bsontype.Timestamp: |
| 273 | length = 8 |
| 274 | case bsontype.Decimal128: |
| 275 | length = 16 |
| 276 | case bsontype.Int32: |
| 277 | length = 4 |
| 278 | case bsontype.JavaScript, bsontype.String, bsontype.Symbol: |
| 279 | length, err = vr.peekLength() |
| 280 | length += 4 |
| 281 | case bsontype.MaxKey, bsontype.MinKey, bsontype.Null, bsontype.Undefined: |
| 282 | length = 0 |
| 283 | case bsontype.ObjectID: |
| 284 | length = 12 |
| 285 | case bsontype.Regex: |
| 286 | regex := bytes.IndexByte(vr.d[vr.offset:], 0x00) |
| 287 | if regex < 0 { |
| 288 | err = io.EOF |
| 289 | break |
| 290 | } |
| 291 | pattern := bytes.IndexByte(vr.d[regex+1:], 0x00) |
| 292 | if pattern < 0 { |
| 293 | err = io.EOF |
| 294 | break |
| 295 | } |
| 296 | length = int32(int64(regex) + 1 + int64(pattern) + 1 - vr.offset) |
| 297 | default: |
| 298 | return 0, fmt.Errorf("attempted to read bytes of unknown BSON type %v", vr.stack[vr.frame].vType) |
| 299 | } |
| 300 | |
| 301 | return length, err |
| 302 | } |
| 303 | |
| 304 | func (vr *valueReader) ReadValueBytes(dst []byte) (bsontype.Type, []byte, error) { |
| 305 | switch vr.stack[vr.frame].mode { |
| 306 | case mTopLevel: |
| 307 | length, err := vr.peekLength() |
| 308 | if err != nil { |
| 309 | return bsontype.Type(0), nil, err |
| 310 | } |
| 311 | dst, err = vr.appendBytes(dst, length) |
| 312 | if err != nil { |
| 313 | return bsontype.Type(0), nil, err |
| 314 | } |
| 315 | return bsontype.Type(0), dst, nil |
| 316 | case mElement, mValue: |
| 317 | length, err := vr.nextElementLength() |
| 318 | if err != nil { |
| 319 | return bsontype.Type(0), dst, err |
| 320 | } |
| 321 | |
| 322 | dst, err = vr.appendBytes(dst, length) |
| 323 | t := vr.stack[vr.frame].vType |
| 324 | vr.pop() |
| 325 | return t, dst, err |
| 326 | default: |
| 327 | return bsontype.Type(0), nil, vr.invalidTransitionErr(0, "ReadValueBytes", []mode{mElement, mValue}) |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | func (vr *valueReader) Skip() error { |
| 332 | switch vr.stack[vr.frame].mode { |
| 333 | case mElement, mValue: |
| 334 | default: |
| 335 | return vr.invalidTransitionErr(0, "Skip", []mode{mElement, mValue}) |
| 336 | } |
| 337 | |
| 338 | length, err := vr.nextElementLength() |
| 339 | if err != nil { |
| 340 | return err |
| 341 | } |
| 342 | |
| 343 | err = vr.skipBytes(length) |
| 344 | vr.pop() |
| 345 | return err |
| 346 | } |
| 347 | |
| 348 | func (vr *valueReader) ReadArray() (ArrayReader, error) { |
| 349 | if err := vr.ensureElementValue(bsontype.Array, mArray, "ReadArray"); err != nil { |
| 350 | return nil, err |
| 351 | } |
| 352 | |
| 353 | err := vr.pushArray() |
| 354 | if err != nil { |
| 355 | return nil, err |
| 356 | } |
| 357 | |
| 358 | return vr, nil |
| 359 | } |
| 360 | |
| 361 | func (vr *valueReader) ReadBinary() (b []byte, btype byte, err error) { |
| 362 | if err := vr.ensureElementValue(bsontype.Binary, 0, "ReadBinary"); err != nil { |
| 363 | return nil, 0, err |
| 364 | } |
| 365 | |
| 366 | length, err := vr.readLength() |
| 367 | if err != nil { |
| 368 | return nil, 0, err |
| 369 | } |
| 370 | |
| 371 | btype, err = vr.readByte() |
| 372 | if err != nil { |
| 373 | return nil, 0, err |
| 374 | } |
| 375 | |
| 376 | if btype == 0x02 { |
| 377 | length, err = vr.readLength() |
| 378 | if err != nil { |
| 379 | return nil, 0, err |
| 380 | } |
| 381 | } |
| 382 | |
| 383 | b, err = vr.readBytes(length) |
| 384 | if err != nil { |
| 385 | return nil, 0, err |
| 386 | } |
| 387 | |
| 388 | vr.pop() |
| 389 | return b, btype, nil |
| 390 | } |
| 391 | |
| 392 | func (vr *valueReader) ReadBoolean() (bool, error) { |
| 393 | if err := vr.ensureElementValue(bsontype.Boolean, 0, "ReadBoolean"); err != nil { |
| 394 | return false, err |
| 395 | } |
| 396 | |
| 397 | b, err := vr.readByte() |
| 398 | if err != nil { |
| 399 | return false, err |
| 400 | } |
| 401 | |
| 402 | if b > 1 { |
| 403 | return false, fmt.Errorf("invalid byte for boolean, %b", b) |
| 404 | } |
| 405 | |
| 406 | vr.pop() |
| 407 | return b == 1, nil |
| 408 | } |
| 409 | |
| 410 | func (vr *valueReader) ReadDocument() (DocumentReader, error) { |
| 411 | switch vr.stack[vr.frame].mode { |
| 412 | case mTopLevel: |
| 413 | // read size |
| 414 | size, err := vr.readLength() |
| 415 | if err != nil { |
| 416 | return nil, err |
| 417 | } |
| 418 | if int(size) != len(vr.d) { |
| 419 | return nil, fmt.Errorf("invalid document length") |
| 420 | } |
| 421 | vr.stack[vr.frame].end = int64(size) + vr.offset - 4 |
| 422 | return vr, nil |
| 423 | case mElement, mValue: |
| 424 | if vr.stack[vr.frame].vType != bsontype.EmbeddedDocument { |
| 425 | return nil, vr.typeError(bsontype.EmbeddedDocument) |
| 426 | } |
| 427 | default: |
| 428 | return nil, vr.invalidTransitionErr(mDocument, "ReadDocument", []mode{mTopLevel, mElement, mValue}) |
| 429 | } |
| 430 | |
| 431 | err := vr.pushDocument() |
| 432 | if err != nil { |
| 433 | return nil, err |
| 434 | } |
| 435 | |
| 436 | return vr, nil |
| 437 | } |
| 438 | |
| 439 | func (vr *valueReader) ReadCodeWithScope() (code string, dr DocumentReader, err error) { |
| 440 | if err := vr.ensureElementValue(bsontype.CodeWithScope, 0, "ReadCodeWithScope"); err != nil { |
| 441 | return "", nil, err |
| 442 | } |
| 443 | |
| 444 | totalLength, err := vr.readLength() |
| 445 | if err != nil { |
| 446 | return "", nil, err |
| 447 | } |
| 448 | strLength, err := vr.readLength() |
| 449 | if err != nil { |
| 450 | return "", nil, err |
| 451 | } |
| 452 | strBytes, err := vr.readBytes(strLength) |
| 453 | if err != nil { |
| 454 | return "", nil, err |
| 455 | } |
| 456 | code = string(strBytes[:len(strBytes)-1]) |
| 457 | |
| 458 | size, err := vr.pushCodeWithScope() |
| 459 | if err != nil { |
| 460 | return "", nil, err |
| 461 | } |
| 462 | |
| 463 | // The total length should equal: |
| 464 | // 4 (total length) + strLength + 4 (the length of str itself) + (document length) |
| 465 | componentsLength := int64(4+strLength+4) + size |
| 466 | if int64(totalLength) != componentsLength { |
| 467 | return "", nil, fmt.Errorf( |
| 468 | "length of CodeWithScope does not match lengths of components; total: %d; components: %d", |
| 469 | totalLength, componentsLength, |
| 470 | ) |
| 471 | } |
| 472 | return code, vr, nil |
| 473 | } |
| 474 | |
| 475 | func (vr *valueReader) ReadDBPointer() (ns string, oid primitive.ObjectID, err error) { |
| 476 | if err := vr.ensureElementValue(bsontype.DBPointer, 0, "ReadDBPointer"); err != nil { |
| 477 | return "", oid, err |
| 478 | } |
| 479 | |
| 480 | ns, err = vr.readString() |
| 481 | if err != nil { |
| 482 | return "", oid, err |
| 483 | } |
| 484 | |
| 485 | oidbytes, err := vr.readBytes(12) |
| 486 | if err != nil { |
| 487 | return "", oid, err |
| 488 | } |
| 489 | |
| 490 | copy(oid[:], oidbytes) |
| 491 | |
| 492 | vr.pop() |
| 493 | return ns, oid, nil |
| 494 | } |
| 495 | |
| 496 | func (vr *valueReader) ReadDateTime() (int64, error) { |
| 497 | if err := vr.ensureElementValue(bsontype.DateTime, 0, "ReadDateTime"); err != nil { |
| 498 | return 0, err |
| 499 | } |
| 500 | |
| 501 | i, err := vr.readi64() |
| 502 | if err != nil { |
| 503 | return 0, err |
| 504 | } |
| 505 | |
| 506 | vr.pop() |
| 507 | return i, nil |
| 508 | } |
| 509 | |
| 510 | func (vr *valueReader) ReadDecimal128() (primitive.Decimal128, error) { |
| 511 | if err := vr.ensureElementValue(bsontype.Decimal128, 0, "ReadDecimal128"); err != nil { |
| 512 | return primitive.Decimal128{}, err |
| 513 | } |
| 514 | |
| 515 | b, err := vr.readBytes(16) |
| 516 | if err != nil { |
| 517 | return primitive.Decimal128{}, err |
| 518 | } |
| 519 | |
| 520 | l := binary.LittleEndian.Uint64(b[0:8]) |
| 521 | h := binary.LittleEndian.Uint64(b[8:16]) |
| 522 | |
| 523 | vr.pop() |
| 524 | return primitive.NewDecimal128(h, l), nil |
| 525 | } |
| 526 | |
| 527 | func (vr *valueReader) ReadDouble() (float64, error) { |
| 528 | if err := vr.ensureElementValue(bsontype.Double, 0, "ReadDouble"); err != nil { |
| 529 | return 0, err |
| 530 | } |
| 531 | |
| 532 | u, err := vr.readu64() |
| 533 | if err != nil { |
| 534 | return 0, err |
| 535 | } |
| 536 | |
| 537 | vr.pop() |
| 538 | return math.Float64frombits(u), nil |
| 539 | } |
| 540 | |
| 541 | func (vr *valueReader) ReadInt32() (int32, error) { |
| 542 | if err := vr.ensureElementValue(bsontype.Int32, 0, "ReadInt32"); err != nil { |
| 543 | return 0, err |
| 544 | } |
| 545 | |
| 546 | vr.pop() |
| 547 | return vr.readi32() |
| 548 | } |
| 549 | |
| 550 | func (vr *valueReader) ReadInt64() (int64, error) { |
| 551 | if err := vr.ensureElementValue(bsontype.Int64, 0, "ReadInt64"); err != nil { |
| 552 | return 0, err |
| 553 | } |
| 554 | |
| 555 | vr.pop() |
| 556 | return vr.readi64() |
| 557 | } |
| 558 | |
| 559 | func (vr *valueReader) ReadJavascript() (code string, err error) { |
| 560 | if err := vr.ensureElementValue(bsontype.JavaScript, 0, "ReadJavascript"); err != nil { |
| 561 | return "", err |
| 562 | } |
| 563 | |
| 564 | vr.pop() |
| 565 | return vr.readString() |
| 566 | } |
| 567 | |
| 568 | func (vr *valueReader) ReadMaxKey() error { |
| 569 | if err := vr.ensureElementValue(bsontype.MaxKey, 0, "ReadMaxKey"); err != nil { |
| 570 | return err |
| 571 | } |
| 572 | |
| 573 | vr.pop() |
| 574 | return nil |
| 575 | } |
| 576 | |
| 577 | func (vr *valueReader) ReadMinKey() error { |
| 578 | if err := vr.ensureElementValue(bsontype.MinKey, 0, "ReadMinKey"); err != nil { |
| 579 | return err |
| 580 | } |
| 581 | |
| 582 | vr.pop() |
| 583 | return nil |
| 584 | } |
| 585 | |
| 586 | func (vr *valueReader) ReadNull() error { |
| 587 | if err := vr.ensureElementValue(bsontype.Null, 0, "ReadNull"); err != nil { |
| 588 | return err |
| 589 | } |
| 590 | |
| 591 | vr.pop() |
| 592 | return nil |
| 593 | } |
| 594 | |
| 595 | func (vr *valueReader) ReadObjectID() (primitive.ObjectID, error) { |
| 596 | if err := vr.ensureElementValue(bsontype.ObjectID, 0, "ReadObjectID"); err != nil { |
| 597 | return primitive.ObjectID{}, err |
| 598 | } |
| 599 | |
| 600 | oidbytes, err := vr.readBytes(12) |
| 601 | if err != nil { |
| 602 | return primitive.ObjectID{}, err |
| 603 | } |
| 604 | |
| 605 | var oid primitive.ObjectID |
| 606 | copy(oid[:], oidbytes) |
| 607 | |
| 608 | vr.pop() |
| 609 | return oid, nil |
| 610 | } |
| 611 | |
| 612 | func (vr *valueReader) ReadRegex() (string, string, error) { |
| 613 | if err := vr.ensureElementValue(bsontype.Regex, 0, "ReadRegex"); err != nil { |
| 614 | return "", "", err |
| 615 | } |
| 616 | |
| 617 | pattern, err := vr.readCString() |
| 618 | if err != nil { |
| 619 | return "", "", err |
| 620 | } |
| 621 | |
| 622 | options, err := vr.readCString() |
| 623 | if err != nil { |
| 624 | return "", "", err |
| 625 | } |
| 626 | |
| 627 | vr.pop() |
| 628 | return pattern, options, nil |
| 629 | } |
| 630 | |
| 631 | func (vr *valueReader) ReadString() (string, error) { |
| 632 | if err := vr.ensureElementValue(bsontype.String, 0, "ReadString"); err != nil { |
| 633 | return "", err |
| 634 | } |
| 635 | |
| 636 | vr.pop() |
| 637 | return vr.readString() |
| 638 | } |
| 639 | |
| 640 | func (vr *valueReader) ReadSymbol() (symbol string, err error) { |
| 641 | if err := vr.ensureElementValue(bsontype.Symbol, 0, "ReadSymbol"); err != nil { |
| 642 | return "", err |
| 643 | } |
| 644 | |
| 645 | vr.pop() |
| 646 | return vr.readString() |
| 647 | } |
| 648 | |
| 649 | func (vr *valueReader) ReadTimestamp() (t uint32, i uint32, err error) { |
| 650 | if err := vr.ensureElementValue(bsontype.Timestamp, 0, "ReadTimestamp"); err != nil { |
| 651 | return 0, 0, err |
| 652 | } |
| 653 | |
| 654 | i, err = vr.readu32() |
| 655 | if err != nil { |
| 656 | return 0, 0, err |
| 657 | } |
| 658 | |
| 659 | t, err = vr.readu32() |
| 660 | if err != nil { |
| 661 | return 0, 0, err |
| 662 | } |
| 663 | |
| 664 | vr.pop() |
| 665 | return t, i, nil |
| 666 | } |
| 667 | |
| 668 | func (vr *valueReader) ReadUndefined() error { |
| 669 | if err := vr.ensureElementValue(bsontype.Undefined, 0, "ReadUndefined"); err != nil { |
| 670 | return err |
| 671 | } |
| 672 | |
| 673 | vr.pop() |
| 674 | return nil |
| 675 | } |
| 676 | |
| 677 | func (vr *valueReader) ReadElement() (string, ValueReader, error) { |
| 678 | switch vr.stack[vr.frame].mode { |
| 679 | case mTopLevel, mDocument, mCodeWithScope: |
| 680 | default: |
| 681 | return "", nil, vr.invalidTransitionErr(mElement, "ReadElement", []mode{mTopLevel, mDocument, mCodeWithScope}) |
| 682 | } |
| 683 | |
| 684 | t, err := vr.readByte() |
| 685 | if err != nil { |
| 686 | return "", nil, err |
| 687 | } |
| 688 | |
| 689 | if t == 0 { |
| 690 | if vr.offset != vr.stack[vr.frame].end { |
| 691 | return "", nil, vr.invalidDocumentLengthError() |
| 692 | } |
| 693 | |
| 694 | vr.pop() |
| 695 | return "", nil, ErrEOD |
| 696 | } |
| 697 | |
| 698 | name, err := vr.readCString() |
| 699 | if err != nil { |
| 700 | return "", nil, err |
| 701 | } |
| 702 | |
| 703 | vr.pushElement(bsontype.Type(t)) |
| 704 | return name, vr, nil |
| 705 | } |
| 706 | |
| 707 | func (vr *valueReader) ReadValue() (ValueReader, error) { |
| 708 | switch vr.stack[vr.frame].mode { |
| 709 | case mArray: |
| 710 | default: |
| 711 | return nil, vr.invalidTransitionErr(mValue, "ReadValue", []mode{mArray}) |
| 712 | } |
| 713 | |
| 714 | t, err := vr.readByte() |
| 715 | if err != nil { |
| 716 | return nil, err |
| 717 | } |
| 718 | |
| 719 | if t == 0 { |
| 720 | if vr.offset != vr.stack[vr.frame].end { |
| 721 | return nil, vr.invalidDocumentLengthError() |
| 722 | } |
| 723 | |
| 724 | vr.pop() |
| 725 | return nil, ErrEOA |
| 726 | } |
| 727 | |
| 728 | _, err = vr.readCString() |
| 729 | if err != nil { |
| 730 | return nil, err |
| 731 | } |
| 732 | |
| 733 | vr.pushValue(bsontype.Type(t)) |
| 734 | return vr, nil |
| 735 | } |
| 736 | |
| 737 | func (vr *valueReader) readBytes(length int32) ([]byte, error) { |
| 738 | if length < 0 { |
| 739 | return nil, fmt.Errorf("invalid length: %d", length) |
| 740 | } |
| 741 | |
| 742 | if vr.offset+int64(length) > int64(len(vr.d)) { |
| 743 | return nil, io.EOF |
| 744 | } |
| 745 | |
| 746 | start := vr.offset |
| 747 | vr.offset += int64(length) |
| 748 | return vr.d[start : start+int64(length)], nil |
| 749 | } |
| 750 | |
| 751 | func (vr *valueReader) appendBytes(dst []byte, length int32) ([]byte, error) { |
| 752 | if vr.offset+int64(length) > int64(len(vr.d)) { |
| 753 | return nil, io.EOF |
| 754 | } |
| 755 | |
| 756 | start := vr.offset |
| 757 | vr.offset += int64(length) |
| 758 | return append(dst, vr.d[start:start+int64(length)]...), nil |
| 759 | } |
| 760 | |
| 761 | func (vr *valueReader) skipBytes(length int32) error { |
| 762 | if vr.offset+int64(length) > int64(len(vr.d)) { |
| 763 | return io.EOF |
| 764 | } |
| 765 | |
| 766 | vr.offset += int64(length) |
| 767 | return nil |
| 768 | } |
| 769 | |
| 770 | func (vr *valueReader) readByte() (byte, error) { |
| 771 | if vr.offset+1 > int64(len(vr.d)) { |
| 772 | return 0x0, io.EOF |
| 773 | } |
| 774 | |
| 775 | vr.offset++ |
| 776 | return vr.d[vr.offset-1], nil |
| 777 | } |
| 778 | |
| 779 | func (vr *valueReader) readCString() (string, error) { |
| 780 | idx := bytes.IndexByte(vr.d[vr.offset:], 0x00) |
| 781 | if idx < 0 { |
| 782 | return "", io.EOF |
| 783 | } |
| 784 | start := vr.offset |
| 785 | // idx does not include the null byte |
| 786 | vr.offset += int64(idx) + 1 |
| 787 | return string(vr.d[start : start+int64(idx)]), nil |
| 788 | } |
| 789 | |
| 790 | func (vr *valueReader) skipCString() error { |
| 791 | idx := bytes.IndexByte(vr.d[vr.offset:], 0x00) |
| 792 | if idx < 0 { |
| 793 | return io.EOF |
| 794 | } |
| 795 | // idx does not include the null byte |
| 796 | vr.offset += int64(idx) + 1 |
| 797 | return nil |
| 798 | } |
| 799 | |
| 800 | func (vr *valueReader) readString() (string, error) { |
| 801 | length, err := vr.readLength() |
| 802 | if err != nil { |
| 803 | return "", err |
| 804 | } |
| 805 | |
| 806 | if int64(length)+vr.offset > int64(len(vr.d)) { |
| 807 | return "", io.EOF |
| 808 | } |
| 809 | |
| 810 | if length <= 0 { |
| 811 | return "", fmt.Errorf("invalid string length: %d", length) |
| 812 | } |
| 813 | |
| 814 | if vr.d[vr.offset+int64(length)-1] != 0x00 { |
| 815 | return "", fmt.Errorf("string does not end with null byte, but with %v", vr.d[vr.offset+int64(length)-1]) |
| 816 | } |
| 817 | |
| 818 | start := vr.offset |
| 819 | vr.offset += int64(length) |
| 820 | |
| 821 | if length == 2 { |
| 822 | asciiByte := vr.d[start] |
| 823 | if asciiByte > unicode.MaxASCII { |
| 824 | return "", fmt.Errorf("invalid ascii byte") |
| 825 | } |
| 826 | } |
| 827 | |
| 828 | return string(vr.d[start : start+int64(length)-1]), nil |
| 829 | } |
| 830 | |
| 831 | func (vr *valueReader) peekLength() (int32, error) { |
| 832 | if vr.offset+4 > int64(len(vr.d)) { |
| 833 | return 0, io.EOF |
| 834 | } |
| 835 | |
| 836 | idx := vr.offset |
| 837 | return (int32(vr.d[idx]) | int32(vr.d[idx+1])<<8 | int32(vr.d[idx+2])<<16 | int32(vr.d[idx+3])<<24), nil |
| 838 | } |
| 839 | |
| 840 | func (vr *valueReader) readLength() (int32, error) { return vr.readi32() } |
| 841 | |
| 842 | func (vr *valueReader) readi32() (int32, error) { |
| 843 | if vr.offset+4 > int64(len(vr.d)) { |
| 844 | return 0, io.EOF |
| 845 | } |
| 846 | |
| 847 | idx := vr.offset |
| 848 | vr.offset += 4 |
| 849 | return (int32(vr.d[idx]) | int32(vr.d[idx+1])<<8 | int32(vr.d[idx+2])<<16 | int32(vr.d[idx+3])<<24), nil |
| 850 | } |
| 851 | |
| 852 | func (vr *valueReader) readu32() (uint32, error) { |
| 853 | if vr.offset+4 > int64(len(vr.d)) { |
| 854 | return 0, io.EOF |
| 855 | } |
| 856 | |
| 857 | idx := vr.offset |
| 858 | vr.offset += 4 |
| 859 | return (uint32(vr.d[idx]) | uint32(vr.d[idx+1])<<8 | uint32(vr.d[idx+2])<<16 | uint32(vr.d[idx+3])<<24), nil |
| 860 | } |
| 861 | |
| 862 | func (vr *valueReader) readi64() (int64, error) { |
| 863 | if vr.offset+8 > int64(len(vr.d)) { |
| 864 | return 0, io.EOF |
| 865 | } |
| 866 | |
| 867 | idx := vr.offset |
| 868 | vr.offset += 8 |
| 869 | return int64(vr.d[idx]) | int64(vr.d[idx+1])<<8 | int64(vr.d[idx+2])<<16 | int64(vr.d[idx+3])<<24 | |
| 870 | int64(vr.d[idx+4])<<32 | int64(vr.d[idx+5])<<40 | int64(vr.d[idx+6])<<48 | int64(vr.d[idx+7])<<56, nil |
| 871 | } |
| 872 | |
| 873 | func (vr *valueReader) readu64() (uint64, error) { |
| 874 | if vr.offset+8 > int64(len(vr.d)) { |
| 875 | return 0, io.EOF |
| 876 | } |
| 877 | |
| 878 | idx := vr.offset |
| 879 | vr.offset += 8 |
| 880 | return uint64(vr.d[idx]) | uint64(vr.d[idx+1])<<8 | uint64(vr.d[idx+2])<<16 | uint64(vr.d[idx+3])<<24 | |
| 881 | uint64(vr.d[idx+4])<<32 | uint64(vr.d[idx+5])<<40 | uint64(vr.d[idx+6])<<48 | uint64(vr.d[idx+7])<<56, nil |
| 882 | } |