forked from mongodb/mongo-go-driver
-
Notifications
You must be signed in to change notification settings - Fork 0
/
document.go
720 lines (633 loc) · 18.7 KB
/
document.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package bson
import (
"bytes"
"errors"
"fmt"
"io"
"sort"
"strconv"
"github.com/mongodb/mongo-go-driver/bson/elements"
)
// ErrInvalidReadOnlyDocument indicates that the underlying bytes of a bson.Reader are invalid.
var ErrInvalidReadOnlyDocument = errors.New("invalid read-only document")
// ErrInvalidKey indicates that the BSON representation of a key is missing a null terminator.
var ErrInvalidKey = errors.New("invalid document key")
// ErrInvalidArrayKey indicates that a key that isn't a positive integer was used to lookup an
// element in an array.
var ErrInvalidArrayKey = errors.New("invalid array key")
// ErrInvalidLength indicates that a length in a binary representation of a BSON document is invalid.
var ErrInvalidLength = errors.New("document length is invalid")
// ErrEmptyKey indicates that no key was provided to a Lookup method.
var ErrEmptyKey = errors.New("empty key provided")
// ErrNilElement indicates that a nil element was provided when none was expected.
var ErrNilElement = errors.New("element is nil")
// ErrNilDocument indicates that an operation was attempted on a nil *bson.Document.
var ErrNilDocument = errors.New("document is nil")
// ErrInvalidDocumentType indicates that a type which doesn't represent a BSON document was
// was provided when a document was expected.
var ErrInvalidDocumentType = errors.New("invalid document type")
// ErrInvalidDepthTraversal indicates that a provided path of keys to a nested value in a document
// does not exist.
//
// TODO(skriptble): This error message is pretty awful.
// Please fix.
var ErrInvalidDepthTraversal = errors.New("invalid depth traversal")
// ErrElementNotFound indicates that an Element matching a certain condition does not exist.
var ErrElementNotFound = errors.New("element not found")
// ErrOutOfBounds indicates that an index provided to access something was invalid.
var ErrOutOfBounds = errors.New("out of bounds")
// Document is a mutable ordered map that compactly represents a BSON document.
type Document struct {
// The default behavior or Append, Prepend, and Replace is to panic on the
// insertion of a nil element. Setting IgnoreNilInsert to true will instead
// silently ignore any nil parameters to these methods.
IgnoreNilInsert bool
elems []*Element
index []uint32
}
// NewDocument creates an empty Document. The numberOfElems parameter will
// preallocate the underlying storage which can prevent extra allocations.
func NewDocument(elems ...*Element) *Document {
doc := &Document{
elems: make([]*Element, 0, len(elems)),
index: make([]uint32, 0, len(elems)),
}
doc.Append(elems...)
return doc
}
// ReadDocument will create a Document using the provided slice of bytes. If the
// slice of bytes is not a valid BSON document, this method will return an error.
func ReadDocument(b []byte) (*Document, error) {
var doc = new(Document)
err := doc.UnmarshalBSON(b)
if err != nil {
return nil, err
}
return doc, nil
}
// Len returns the number of elements in the document.
func (d *Document) Len() int {
if d == nil {
panic(ErrNilDocument)
}
return len(d.elems)
}
// Keys returns all of the element keys for this document. If recursive is true,
// this method will also return the keys of any subdocuments or arrays.
func (d *Document) Keys(recursive bool) (Keys, error) {
if d == nil {
return nil, ErrNilDocument
}
return d.recursiveKeys(recursive)
}
// recursiveKeys handles the recursion case for retrieving all of a Document's
// keys.
func (d *Document) recursiveKeys(recursive bool, prefix ...string) (Keys, error) {
if d == nil {
return nil, ErrNilDocument
}
ks := make(Keys, 0, len(d.elems))
for _, elem := range d.elems {
key := elem.Key()
ks = append(ks, Key{Prefix: prefix, Name: key})
if !recursive {
continue
}
// TODO(skriptble): Should we support getting the keys of a code with
// scope document?
switch elem.value.Type() {
case '\x03':
subprefix := append(prefix, key)
subkeys, err := elem.value.MutableDocument().recursiveKeys(recursive, subprefix...)
if err != nil {
return nil, err
}
ks = append(ks, subkeys...)
case '\x04':
subprefix := append(prefix, key)
subkeys, err := elem.value.MutableArray().doc.recursiveKeys(recursive, subprefix...)
if err != nil {
return nil, err
}
ks = append(ks, subkeys...)
}
}
return ks, nil
}
// Append adds each element to the end of the document, in order. If a nil element is passed
// as a parameter this method will panic. To change this behavior to silently
// ignore a nil element, set IgnoreNilInsert to true on the Document.
//
// If a nil element is inserted and this method panics, it does not remove the
// previously added elements.
func (d *Document) Append(elems ...*Element) *Document {
if d == nil {
panic(ErrNilDocument)
}
for _, elem := range elems {
if elem == nil {
if d.IgnoreNilInsert {
continue
}
// TODO(skriptble): Maybe Append and Prepend should return an error
// instead of panicking here.
panic(ErrNilElement)
}
d.elems = append(d.elems, elem)
i := sort.Search(len(d.index), func(i int) bool {
return bytes.Compare(
d.keyFromIndex(i), elem.value.data[elem.value.start+1:elem.value.offset]) >= 0
})
if i < len(d.index) {
d.index = append(d.index, 0)
copy(d.index[i+1:], d.index[i:])
d.index[i] = uint32(len(d.elems) - 1)
} else {
d.index = append(d.index, uint32(len(d.elems)-1))
}
}
return d
}
// Prepend adds each element to the beginning of the document, in order. If a nil element is passed
// as a parameter this method will panic. To change this behavior to silently
// ignore a nil element, set IgnoreNilInsert to true on the Document.
//
// If a nil element is inserted and this method panics, it does not remove the
// previously added elements.
func (d *Document) Prepend(elems ...*Element) *Document {
if d == nil {
panic(ErrNilDocument)
}
// In order to insert the prepended elements in order we need to make space
// at the front of the elements slice.
d.elems = append(d.elems, elems...)
copy(d.elems[len(elems):], d.elems)
remaining := len(elems)
for idx, elem := range elems {
if elem == nil {
if d.IgnoreNilInsert {
// Having nil elements in a document would be problematic.
copy(d.elems[idx:], d.elems[idx+1:])
d.elems[len(d.elems)-1] = nil
d.elems = d.elems[:len(d.elems)-1]
continue
}
// Not very efficient, but we're about to blow up so ¯\_(ツ)_/¯
for j := idx; j < remaining; j++ {
copy(d.elems[j:], d.elems[j+1:])
d.elems[len(d.elems)-1] = nil
d.elems = d.elems[:len(d.elems)-1]
}
panic(ErrNilElement)
}
remaining--
d.elems[idx] = elem
i := sort.Search(len(d.index), func(i int) bool {
return bytes.Compare(
d.keyFromIndex(i), elem.value.data[elem.value.start+1:elem.value.offset]) >= 0
})
if i < len(d.index) {
d.index = append(d.index, 0)
copy(d.index[i+1:], d.index[i:])
d.index[i] = uint32(len(d.elems) - 1)
} else {
d.index = append(d.index, uint32(len(d.elems)-1))
}
}
return d
}
// Set replaces an element of a document. If an element with a matching key is
// found, the element will be replaced with the one provided. If the document
// does not have an element with that key, the element is appended to the
// document instead. If a nil element is passed as a parameter this method will
// panic. To change this behavior to silently ignore a nil element, set
// IgnoreNilInsert to true on the Document.
//
// If a nil element is inserted and this method panics, it does not remove the
// previously added elements.
//
// TODO(skriptble): Do we need to panic on a nil element? Semantically, if you
// ask to replace an element in the document with a nil element, you aren't
// asking for anything to be done.
func (d *Document) Set(elem *Element) *Document {
if elem == nil {
if d.IgnoreNilInsert {
return d
}
panic(ErrNilElement)
}
key := elem.Key() + "\x00"
i := sort.Search(len(d.index), func(i int) bool { return bytes.Compare(d.keyFromIndex(i), []byte(key)) >= 0 })
if i < len(d.index) && bytes.Compare(d.keyFromIndex(i), []byte(key)) == 0 {
d.elems[d.index[i]] = elem
return d
}
d.elems = append(d.elems, elem)
position := uint32(len(d.elems) - 1)
if i < len(d.index) {
d.index = append(d.index, 0)
copy(d.index[i+1:], d.index[i:])
d.index[i] = position
} else {
d.index = append(d.index, position)
}
return d
}
// Lookup searches the document and potentially subdocuments or arrays for the
// provided key. Each key provided to this method represents a layer of depth.
func (d *Document) Lookup(key ...string) (*Element, error) {
if d == nil {
return nil, ErrNilDocument
}
if len(key) == 0 {
return nil, ErrEmptyKey
}
var elem *Element
var err error
first := []byte(key[0] + "\x00")
i := sort.Search(len(d.index), func(i int) bool { return bytes.Compare(d.keyFromIndex(i), first) >= 0 })
if i < len(d.index) && bytes.Compare(d.keyFromIndex(i), first) == 0 {
elem = d.elems[d.index[i]]
if len(key) == 1 {
return elem, nil
}
switch elem.value.Type() {
case '\x03':
elem, err = elem.value.MutableDocument().Lookup(key[1:]...)
case '\x04':
index, err := strconv.ParseUint(key[1], 10, 0)
if err != nil {
return nil, ErrInvalidArrayKey
}
val, err := elem.value.MutableArray().lookupTraverse(uint(index), key[2:]...)
if err != nil {
return nil, err
}
elem = &Element{value: val}
default:
// TODO(skriptble): This error message should be more clear, e.g.
// include information about what depth was reached, what the
// incorrect type was, etc...
err = ErrInvalidDepthTraversal
}
}
if err != nil {
return nil, err
}
if elem == nil {
// TODO(skriptble): This should also be a clearer error message.
// Preferably we should track the depth at which the key was not found.
return nil, ErrElementNotFound
}
return elem, nil
}
// Delete removes the keys from the Document. The deleted element is
// returned. If the key does not exist, then nil is returned and the delete is
// a no-op. The same is true if something along the depth tree does not exist
// or is not a traversable type.
//
// TODO(skriptble): This method differs from Lookup when it comes to errors.
// Should this method return errors to be consistent?
func (d *Document) Delete(key ...string) *Element {
if d == nil {
panic(ErrNilDocument)
}
if len(key) == 0 {
return nil
}
// Do a binary search through the index, delete the element from
// the index and delete the element from the elems array.
var elem *Element
first := []byte(key[0] + "\x00")
i := sort.Search(len(d.index), func(i int) bool { return bytes.Compare(d.keyFromIndex(i), first) >= 0 })
if i < len(d.index) && bytes.Compare(d.keyFromIndex(i), first) == 0 {
keyIndex := d.index[i]
elem = d.elems[keyIndex]
if len(key) == 1 {
d.index = append(d.index[:i], d.index[i+1:]...)
d.elems = append(d.elems[:keyIndex], d.elems[keyIndex+1:]...)
return elem
}
switch elem.value.Type() {
case '\x03':
elem = elem.value.MutableDocument().Delete(key[1:]...)
case '\x04':
elem = elem.value.MutableArray().doc.Delete(key[1:]...)
default:
elem = nil
}
}
return elem
}
// ElementAt retrieves the element at the given index in a Document. It panics if the index is
// out-of-bounds.
//
// TODO(skriptble): This method could be variadic and return the element at the
// provided depth.
func (d *Document) ElementAt(index uint) *Element {
if d == nil {
panic(ErrNilDocument)
}
return d.elems[index]
}
// ElementAtOK is the same as ElementAt, but returns a boolean instead of panicking.
func (d *Document) ElementAtOK(index uint) (*Element, bool) {
if d == nil {
return nil, false
}
if index >= uint(len(d.elems)) {
return nil, false
}
return d.ElementAt(index), true
}
// Iterator creates an Iterator for this document and returns it.
func (d *Document) Iterator() *Iterator {
if d == nil {
panic(ErrNilDocument)
}
return newIterator(d)
}
// Concat will take the keys from the provided document and concat them onto
// the end of this document.
//
// doc must be one of the following:
//
// - *Document
// - []byte
// - io.Reader
func (d *Document) Concat(docs ...interface{}) error {
if d == nil {
return ErrNilDocument
}
for _, doc := range docs {
if doc == nil {
if d.IgnoreNilInsert {
continue
}
return ErrNilDocument
}
switch doc := doc.(type) {
case *Document:
if doc == nil {
if d.IgnoreNilInsert {
continue
}
return ErrNilDocument
}
d.Append(doc.elems...)
case []byte:
if err := d.concatReader(Reader(doc)); err != nil {
return err
}
case Reader:
if err := d.concatReader(doc); err != nil {
return err
}
default:
return ErrInvalidDocumentType
}
}
return nil
}
func (d *Document) concatReader(r Reader) error {
_, err := r.readElements(func(e *Element) error {
d.Append(e)
return nil
})
return err
}
// Reset clears a document so it can be reused. This method clears references
// to the underlying pointers to elements so they can be garbage collected.
func (d *Document) Reset() {
if d == nil {
panic(ErrNilDocument)
}
for idx := range d.elems {
d.elems[idx] = nil
}
d.elems = d.elems[:0]
d.index = d.index[:0]
}
// Validate validates the document and returns its total size.
func (d *Document) Validate() (uint32, error) {
if d == nil {
return 0, ErrNilDocument
}
// Header and Footer
var size uint32 = 4 + 1
for _, elem := range d.elems {
n, err := elem.Validate()
if err != nil {
return 0, err
}
size += n
}
return size, nil
}
// validates the document and returns its total size. This method has
// bookkeeping parameters to prevent a stack overflow.
func (d *Document) validate(currentDepth, maxDepth uint32) (uint32, error) {
if d == nil {
return 0, ErrNilDocument
}
return 0, nil
}
// WriteTo implements the io.WriterTo interface.
//
// TODO(skriptble): We can optimize this by having creating implementations of
// writeByteSlice that write directly to an io.Writer instead.
func (d *Document) WriteTo(w io.Writer) (int64, error) {
if d == nil {
return 0, ErrNilDocument
}
b, err := d.MarshalBSON()
if err != nil {
return 0, err
}
n, err := w.Write(b)
return int64(n), err
}
// WriteDocument will serialize this document to the provided writer beginning
// at the provided start position.
func (d *Document) WriteDocument(start uint, writer interface{}) (int64, error) {
if d == nil {
return 0, ErrNilDocument
}
var total int64
var pos = start
size, err := d.Validate()
if err != nil {
return total, err
}
switch w := writer.(type) {
case []byte:
n, err := d.writeByteSlice(pos, size, w)
total += n
pos += uint(n)
if err != nil {
return total, err
}
default:
return 0, ErrInvalidWriter
}
return total, nil
}
// writeByteSlice handles serializing this document to a slice of bytes starting
// at the given start position.
func (d *Document) writeByteSlice(start uint, size uint32, b []byte) (int64, error) {
if d == nil {
return 0, ErrNilDocument
}
var total int64
var pos = start
if len(b) < int(start)+int(size) {
return 0, NewErrTooSmall()
}
n, err := elements.Int32.Encode(start, b, int32(size))
total += int64(n)
pos += uint(n)
if err != nil {
return total, err
}
for _, elem := range d.elems {
n, err := elem.writeElement(true, pos, b)
total += int64(n)
pos += uint(n)
if err != nil {
return total, err
}
}
n, err = elements.Byte.Encode(pos, b, '\x00')
total += int64(n)
pos += uint(n)
if err != nil {
return total, err
}
return total, nil
}
// MarshalBSON implements the Marshaler interface.
func (d *Document) MarshalBSON() ([]byte, error) {
if d == nil {
return nil, ErrNilDocument
}
size, err := d.Validate()
if err != nil {
return nil, err
}
b := make([]byte, size)
_, err = d.writeByteSlice(0, size, b)
if err != nil {
return nil, err
}
return b, nil
}
// UnmarshalBSON implements the Unmarshaler interface.
func (d *Document) UnmarshalBSON(b []byte) error {
if d == nil {
return ErrNilDocument
}
// Read byte array
// - Create an Element for each element found
// - Update the index with the key of the element
// TODO: Maybe do 2 pass and alloc the elems and index once?
// We should benchmark 2 pass vs multiple allocs for growing the slice
_, err := Reader(b).readElements(func(elem *Element) error {
d.elems = append(d.elems, elem)
i := sort.Search(len(d.index), func(i int) bool {
return bytes.Compare(
d.keyFromIndex(i), elem.value.data[elem.value.start+1:elem.value.offset]) >= 0
})
if i < len(d.index) {
d.index = append(d.index, 0)
copy(d.index[i+1:], d.index[i:])
d.index[i] = uint32(len(d.elems) - 1)
} else {
d.index = append(d.index, uint32(len(d.elems)-1))
}
return nil
})
return err
}
// ReadFrom will read one BSON document from the given io.Reader.
func (d *Document) ReadFrom(r io.Reader) (int64, error) {
if d == nil {
return 0, ErrNilDocument
}
var total int64
sizeBuf := make([]byte, 4)
n, err := io.ReadFull(r, sizeBuf)
total += int64(n)
if err != nil {
return total, err
}
givenLength := readi32(sizeBuf)
b := make([]byte, givenLength)
copy(b[0:4], sizeBuf)
n, err = io.ReadFull(r, b[4:])
total += int64(n)
if err != nil {
return total, err
}
err = d.UnmarshalBSON(b)
return total, err
}
// keyFromIndex returns the key for the element. The idx parameter is the
// position in the index property, not the elems property. This method is
// mainly used when calling sort.Search.
func (d *Document) keyFromIndex(idx int) []byte {
if d == nil {
panic(ErrNilDocument)
}
haystack := d.elems[d.index[idx]]
return haystack.value.data[haystack.value.start+1 : haystack.value.offset]
}
// Equal compares this document to another, returning true if they are equal.
func (d *Document) Equal(d2 *Document) bool {
if d == nil && d2 == nil {
return true
}
if d == nil || d2 == nil {
return false
}
if (len(d.elems) != len(d2.elems)) || (len(d.index) != len(d2.index)) {
return false
}
for index := range d.elems {
b1, err := d.elems[index].MarshalBSON()
if err != nil {
return false
}
b2, err := d2.elems[index].MarshalBSON()
if err != nil {
return false
}
if !bytes.Equal(b1, b2) {
return false
}
if d.index[index] != d2.index[index] {
return false
}
}
return true
}
// String implements the fmt.Stringer interface.
func (d *Document) String() string {
if d == nil {
return "<nil>"
}
var buf bytes.Buffer
buf.Write([]byte("bson.Document{"))
for idx, elem := range d.elems {
if idx > 0 {
buf.Write([]byte(", "))
}
fmt.Fprintf(&buf, "%s", elem)
}
buf.WriteByte('}')
return buf.String()
}