summaryrefslogtreecommitdiff
path: root/src/mongo/db/pipeline/value.cpp
blob: 9139f0cdbed4703a350208f78fce805be6732007 (plain)
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
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
/**
 * Copyright (c) 2011 10gen Inc.
 *
 * This program is free software: you can redistribute it and/or  modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * As a special exception, the copyright holders give permission to link the
 * code of portions of this program with the OpenSSL library under certain
 * conditions as described in each individual source file and distribute
 * linked combinations including the program with the OpenSSL library. You
 * must comply with the GNU Affero General Public License in all respects for
 * all of the code used other than as permitted herein. If you modify file(s)
 * with this exception, you may extend this exception to your version of the
 * file(s), but you are not obligated to do so. If you do not wish to do so,
 * delete this exception statement from your version. If you delete this
 * exception statement from all source files in the program, then also delete
 * it in the license file.
 */

#include "mongo/pch.h"

#include "mongo/db/pipeline/value.h"

#include <boost/functional/hash.hpp>

#include "mongo/db/jsobj.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/util/mongoutils/str.h"

namespace mongo {
    using namespace mongoutils;

    void ValueStorage::verifyRefCountingIfShould() const {
        switch (type) {
        case MinKey:
        case MaxKey:
        case jstOID:
        case Date:
        case Timestamp:
        case EOO:
        case jstNULL:
        case Undefined:
        case Bool:
        case NumberInt:
        case NumberLong:
        case NumberDouble:
            // the above types never reference external data
            verify(!refCounter);
            break;

        case String:
        case RegEx:
        case Code:
        case Symbol:
            // the above types reference data when not using short-string optimization
            verify(refCounter == !shortStr);
            break;

        case BinData: // TODO this should probably support short-string optimization
        case Array: // TODO this should probably support empty-is-NULL optimization
        case DBRef:
        case CodeWScope:
            // the above types always reference external data.
            verify(refCounter);
            verify(bool(genericRCPtr));
            break;

        case Object:
            // Objects either hold a NULL ptr or should be ref-counting
            verify(refCounter == bool(genericRCPtr));
            break;
        }
    }

    void ValueStorage::putString(const StringData& s) {
        // Note: this also stores data portion of BinData
        const size_t sizeNoNUL = s.size();
        if (sizeNoNUL <= sizeof(shortStrStorage)) {
            shortStr = true;
            shortStrSize = s.size();
            s.copyTo(shortStrStorage, false); // no NUL

            // All memory is zeroed before this is called.
            // Note this may be past end of shortStrStorage and into nulTerminator
            dassert(shortStrStorage[sizeNoNUL] == '\0');
        }
        else {
            putRefCountable(RCString::create(s));
        }
    }

    void ValueStorage::putDocument(const Document& d) {
        putRefCountable(d._storage);
    }

    void ValueStorage::putVector(const RCVector* vec) {
        fassert(16485, vec);
        putRefCountable(vec);
    }

    void ValueStorage::putRegEx(const BSONRegEx& re) {
        const size_t patternLen = re.pattern.size();
        const size_t flagsLen = re.flags.size();
        const size_t totalLen = patternLen + 1/*middle NUL*/ + flagsLen;

        // Need to copy since putString doesn't support scatter-gather.
        boost::scoped_array<char> buf (new char[totalLen]);
        re.pattern.copyTo(buf.get(), true);
        re.flags.copyTo(buf.get() + patternLen + 1, false); // no NUL
        putString(StringData(buf.get(), totalLen));
    }

    Document ValueStorage::getDocument() const {
        if (!genericRCPtr)
            return Document();

        dassert(typeid(*genericRCPtr) == typeid(const DocumentStorage));
        const DocumentStorage* documentPtr = static_cast<const DocumentStorage*>(genericRCPtr);
        return Document(documentPtr);
    }

    // not in header because document is fwd declared
    Value::Value(const BSONObj& obj) : _storage(Object, Document(obj)) {}

    Value::Value(const BSONElement& elem) : _storage(elem.type()) {
        switch(elem.type()) {
        // These are all type-only, no data
        case EOO:
        case MinKey:
        case MaxKey:
        case Undefined:
        case jstNULL:
            break;

        case NumberDouble:
            _storage.doubleValue = elem.Double();
            break;

        case Code:
        case Symbol:
        case String:
            _storage.putString(StringData(elem.valuestr(), elem.valuestrsize()-1));
            break;

        case Object: {
            _storage.putDocument(Document(elem.embeddedObject()));
            break;
        }

        case Array: {
            intrusive_ptr<RCVector> vec (new RCVector);
            BSONForEach(sub, elem.embeddedObject()) {
                vec->vec.push_back(Value(sub));
            }
            _storage.putVector(vec.get());
            break;
        }

        case jstOID:
            BOOST_STATIC_ASSERT(sizeof(_storage.oid) == sizeof(OID));
            memcpy(_storage.oid, elem.OID().getData(), sizeof(OID));
            break;

        case Bool:
            _storage.boolValue = elem.boolean();
            break;

        case Date:
            // this is really signed but typed as unsigned for historical reasons
            _storage.dateValue = static_cast<long long>(elem.date().millis);
            break;

        case RegEx: {
            _storage.putRegEx(BSONRegEx(elem.regex(), elem.regexFlags()));
            break;
        }

        case NumberInt:
            _storage.intValue = elem.numberInt();
            break;

        case Timestamp:
            // asDate is a poorly named function that returns a ReplTime
            _storage.timestampValue = elem._opTime().asDate();
            break;

        case NumberLong:
            _storage.longValue = elem.numberLong();
            break;

        case CodeWScope: {
            StringData code (elem.codeWScopeCode(), elem.codeWScopeCodeLen()-1);
            _storage.putCodeWScope(BSONCodeWScope(code, elem.codeWScopeObject()));
            break;
        }

        case BinData: {
            int len;
            const char* data = elem.binData(len);
            _storage.putBinData(BSONBinData(data, len, elem.binDataType()));
            break;
        }

        case DBRef:
            _storage.putDBRef(BSONDBRef(elem.dbrefNS(), elem.dbrefOID()));
            break;
        }
    }

    Value::Value(const BSONArray& arr) : _storage(Array) {
        intrusive_ptr<RCVector> vec (new RCVector);
        BSONForEach(sub, arr) {
            vec->vec.push_back(Value(sub));
        }
        _storage.putVector(vec.get());
    }

    Value Value::createIntOrLong(long long longValue) {
        int intValue = longValue;
        if (intValue != longValue) {
            // it is too large to be an int and should remain a long
            return Value(longValue);
        }

        // should be an int since all arguments were int and it fits
        return Value(intValue);
    }

    double Value::getDouble() const {
        BSONType type = getType();
        if (type == NumberInt)
            return _storage.intValue;
        if (type == NumberLong)
            return static_cast< double >( _storage.longValue );

        verify(type == NumberDouble);
        return _storage.doubleValue;
    }

    Document Value::getDocument() const {
        verify(getType() == Object);
        return _storage.getDocument();
    }

    Value Value::operator[] (size_t index) const {
        if (getType() != Array || index >= getArrayLength())
            return Value();

        return getArray()[index];
    }

    Value Value::operator[] (StringData name) const {
        if (getType() != Object)
            return Value();

        return getDocument()[name];
    }

    BSONObjBuilder& operator << (BSONObjBuilderValueStream& builder, const Value& val) {
        switch(val.getType()) {
        case EOO:          return builder.builder(); // nothing appended
        case MinKey:       return builder << MINKEY;
        case MaxKey:       return builder << MAXKEY;
        case jstNULL:      return builder << BSONNULL;
        case Undefined:    return builder << BSONUndefined;
        case jstOID:       return builder << val.getOid();
        case NumberInt:    return builder << val.getInt();
        case NumberLong:   return builder << val.getLong();
        case NumberDouble: return builder << val.getDouble();
        case String:       return builder << val.getStringData();
        case Bool:         return builder << val.getBool();
        case Date:         return builder << Date_t(val.getDate());
        case Timestamp:    return builder << val.getTimestamp();
        case Object:       return builder << val.getDocument();
        case Symbol:       return builder << BSONSymbol(val.getStringData());
        case Code:         return builder << BSONCode(val.getStringData());
        case RegEx:        return builder << BSONRegEx(val.getRegex(), val.getRegexFlags());

        case DBRef:
            return builder << BSONDBRef(val._storage.getDBRef()->ns, val._storage.getDBRef()->oid);

        case BinData:
            return builder << BSONBinData(val.getStringData().rawData(), // looking for void*
                                          val.getStringData().size(),
                                          val._storage.binDataType());

        case CodeWScope:
            return builder << BSONCodeWScope(val._storage.getCodeWScope()->code,
                                             val._storage.getCodeWScope()->scope);

        case Array: {
            const vector<Value>& array = val.getArray();
            const size_t n = array.size();
            BSONArrayBuilder arrayBuilder(builder.subarrayStart());
            for(size_t i = 0; i < n; i++) {
                array[i].addToBsonArray(&arrayBuilder);
            }
            arrayBuilder.doneFast();
            return builder.builder();
        }
        }
        verify(false);
    }

    void Value::addToBsonObj(BSONObjBuilder* pBuilder, StringData fieldName) const {
        *pBuilder << fieldName << *this;
    }

    void Value::addToBsonArray(BSONArrayBuilder* pBuilder) const {
        if (!missing()) { // don't want to increment builder's counter
            *pBuilder << *this;
        }
    }

    bool Value::coerceToBool() const {
        // TODO Unify the implementation with BSONElement::trueValue().
        switch(getType()) {
        case CodeWScope:
        case MinKey:
        case DBRef:
        case Code:
        case MaxKey:
        case String:
        case Object:
        case Array:
        case BinData:
        case jstOID:
        case Date:
        case RegEx:
        case Symbol:
        case Timestamp:
            return true;

        case EOO:
        case jstNULL:
        case Undefined:
            return false;

        case Bool: return _storage.boolValue;
        case NumberInt: return _storage.intValue;
        case NumberLong: return _storage.longValue;
        case NumberDouble: return _storage.doubleValue;
        }
        verify(false);
    }

    int Value::coerceToInt() const {
        switch(getType()) {
        case NumberInt:
            return _storage.intValue;

        case NumberLong:
            return static_cast<int>(_storage.longValue);

        case NumberDouble:
            return static_cast<int>(_storage.doubleValue);

        default:
            uassert(16003, str::stream() <<
                    "can't convert from BSON type " << typeName(getType()) <<
                    " to int",
                    false);
        } // switch(getType())
    }

    long long Value::coerceToLong() const {
        switch(getType()) {
        case NumberLong:
            return _storage.longValue;

        case NumberInt:
            return static_cast<long long>(_storage.intValue);

        case NumberDouble:
            return static_cast<long long>(_storage.doubleValue);

        default:
            uassert(16004, str::stream() <<
                    "can't convert from BSON type " << typeName(getType()) <<
                    " to long",
                    false);
        } // switch(getType())
    }

    double Value::coerceToDouble() const {
        switch(getType()) {
        case NumberDouble:
            return _storage.doubleValue;

        case NumberInt:
            return static_cast<double>(_storage.intValue);

        case NumberLong:
            return static_cast<double>(_storage.longValue);

        default:
            uassert(16005, str::stream() <<
                    "can't convert from BSON type " << typeName(getType()) <<
                    " to double",
                    false);
        } // switch(getType())
    }

    long long Value::coerceToDate() const {
        switch(getType()) {
        case Date:
            return getDate();

        case Timestamp:
            return getTimestamp().getSecs() * 1000LL;

        default:
            uassert(16006, str::stream() <<
                    "can't convert from BSON type " << typeName(getType()) << " to Date",
                    false);
        } // switch(getType())
    }

    time_t Value::coerceToTimeT() const {
        long long millis = coerceToDate();
        if (millis < 0) {
            // We want the division below to truncate toward -inf rather than 0
            // eg Dec 31, 1969 23:59:58.001 should be -2 seconds rather than -1
            // This is needed to get the correct values from coerceToTM
            if ( -1999 / 1000 != -2) { // this is implementation defined
                millis -= 1000-1;
            }
        }
        const long long seconds = millis / 1000;

        uassert(16421, "Can't handle date values outside of time_t range",
               seconds >= std::numeric_limits<time_t>::min() &&
               seconds <= std::numeric_limits<time_t>::max());

        return static_cast<time_t>(seconds);
    }
    tm Value::coerceToTm() const {
        // See implementation in Date_t.
        // Can't reuse that here because it doesn't support times before 1970
        time_t dtime = coerceToTimeT();
        tm out;

#if defined(_WIN32) // Both the argument order and the return values differ
        bool itWorked = gmtime_s(&out, &dtime) == 0;
#else
        bool itWorked = gmtime_r(&dtime, &out) != NULL;
#endif

        if (!itWorked) {
            if (dtime < 0) {
                // Windows docs say it doesn't support these, but empirically it seems to work
                uasserted(16422, "gmtime failed - your system doesn't support dates before 1970");
            }
            else {
                uasserted(16423, str::stream() << "gmtime failed to convert time_t of " << dtime);
            }
        }

        return out;
    }

    static string tmToISODateString(const tm& time) {
        char buf[128];
        size_t len = strftime(buf, 128, "%Y-%m-%dT%H:%M:%S", &time);
        verify(len > 0);
        verify(len < 128);
        return buf;
    }

    string Value::coerceToString() const {
        stringstream ss;
        switch(getType()) {
        case NumberDouble:
            ss << _storage.doubleValue;
            return ss.str();

        case NumberInt:
            ss << _storage.intValue;
            return ss.str();

        case NumberLong:
            ss << _storage.longValue;
            return ss.str();

        case Code:
        case Symbol:
        case String:
            return getStringData().toString();

        case Timestamp:
            ss << getTimestamp().toStringPretty();
            return ss.str();

        case Date:
            return tmToISODateString(coerceToTm());

        case EOO:
        case jstNULL:
        case Undefined:
            return "";

        default:
            uassert(16007, str::stream() <<
                    "can't convert from BSON type " << typeName(getType()) <<
                    " to String",
                    false);
        } // switch(getType())
    }

    OpTime Value::coerceToTimestamp() const {
        switch(getType()) {
        case Timestamp:
            return getTimestamp();

        default:
            uassert(16378, str::stream() <<
                    "can't convert from BSON type " << typeName(getType()) <<
                    " to timestamp",
                    false);
        } // switch(getType())
    }

    // Helper function for Value::compare.
    // Better than l-r for cases where difference > MAX_INT
    template <typename T>
    inline static int cmp(const T& left, const T& right) {
        if (left < right) {
            return -1;
        }
        else if (left == right) {
            return 0;
        }
        else {
            dassert(left > right);
            return 1;
        }
    }

    // Special case for double since it needs special NaN handling
    inline static int cmp(double left, double right) {
        // The following is lifted directly from compareElementValues
        // to ensure identical handling of NaN
        if (left < right) 
            return -1;
        if (left == right)
            return 0;
        if (isNaN(left))
            return isNaN(right) ? 0 : -1;
        return 1;
    }

    int Value::compare(const Value& rL, const Value& rR) {
        // Note, this function needs to behave identically to BSON's compareElementValues().
        // Additionally, any changes here must be replicated in hash_combine().
        BSONType lType = rL.getType();
        BSONType rType = rR.getType();

        int ret = lType == rType
                    ? 0 // fast-path common case
                    : cmp(canonicalizeBSONType(lType),
                          canonicalizeBSONType(rType));

        if (ret)
            return ret;

        switch(lType) {
        // Order of types is the same as in compareElementValues() to make it easier to verify

        // These are valueless types
        case EOO:
        case Undefined:
        case jstNULL:
        case MaxKey:
        case MinKey:
            return ret;

        case Bool:
            return rL.getBool() - rR.getBool();

        // WARNING: Timestamp and Date have same canonical type, but compare differently.
        // Maintaining behavior from normal BSON.
        case Timestamp: // unsigned
            return cmp(rL._storage.timestampValue, rR._storage.timestampValue);
        case Date: // signed
            return cmp(rL._storage.dateValue, rR._storage.dateValue);

        // Numbers should compare by equivalence even if different types
        case NumberLong:
        case NumberInt:
        case NumberDouble:
            switch (getWidestNumeric(lType, rType)) {
            case NumberDouble: return cmp(rL.getDouble(), rR.getDouble());
            case NumberLong:   return cmp(rL.getLong(),   rR.getLong());
            case NumberInt:    return cmp(rL.getInt(),    rR.getInt());
            default: verify(false);
            }

        case jstOID:
            return memcmp(rL._storage.oid, rR._storage.oid, sizeof(OID));

        case Code:
        case Symbol:
        case String:
            return rL.getStringData().compare(rR.getStringData());

        case Object:
            return Document::compare(rL.getDocument(), rR.getDocument());

        case Array: {
            const vector<Value>& lArr = rL.getArray();
            const vector<Value>& rArr = rR.getArray();

            const size_t elems = min(lArr.size(), rArr.size());
            for (size_t i = 0; i < elems; i++ ) {
                // compare the two corresponding elements
                ret = Value::compare(lArr[i], rArr[i]);
                if (ret)
                    return ret; // values are unequal
            }

            // if we get here we are either equal or one is prefix of the other 
            return cmp(lArr.size(), rArr.size());
        }

        case DBRef: {
            intrusive_ptr<const RCDBRef> l = rL._storage.getDBRef();
            intrusive_ptr<const RCDBRef> r = rR._storage.getDBRef();
            ret = cmp(l->ns.size(), r->ns.size());
            if (ret)
                return ret;

            return l->oid.compare(r->oid);
        }

        case BinData: {
            ret = cmp(rL.getStringData().size(), rR.getStringData().size());
            if (ret)
                return ret;

            // Need to compare as an unsigned char rather than enum since BSON uses memcmp
            ret = cmp(rL._storage.binSubType, rR._storage.binSubType);
            if (ret)
                return ret;

            return rL.getStringData().compare(rR.getStringData());
        }

        case RegEx: // same as String in this impl but keeping order same as compareElementValues
            return rL.getStringData().compare(rR.getStringData());

        case CodeWScope: {
            // This case crazy, but identical to how they are compared in BSON (SERVER-7804)

            intrusive_ptr<const RCCodeWScope> l = rL._storage.getCodeWScope();
            intrusive_ptr<const RCCodeWScope> r = rR._storage.getCodeWScope();

            // This triggers two bugs in codeWScope.
            // Since this is a very rare case I'm not handling it here.
            uassert(16557, "can't compare CodeWScope values containing a NUL byte in the code.",
                    strlen(l->code.c_str()) == l->code.size()
                 && strlen(r->code.c_str()) == r->code.size());

            ret = l->code.compare(r->code);
            if (ret)
                return ret;

            // SERVER-7804
            return strcmp(l->scope.objdata(), r->scope.objdata());
        }
        }
        verify(false);
    }

    void Value::hash_combine(size_t &seed) const {
        BSONType type = getType();

        boost::hash_combine(seed, canonicalizeBSONType(type));

        switch (type) {
        // Order of types is the same as in Value::compare() and compareElementValues().

        // These are valueless types
        case EOO:
        case Undefined:
        case jstNULL:
        case MaxKey:
        case MinKey:
            return;

        case Bool:
            boost::hash_combine(seed, getBool());
            break;

        case Timestamp:
        case Date:
            BOOST_STATIC_ASSERT(sizeof(_storage.dateValue) == sizeof(_storage.timestampValue));
            boost::hash_combine(seed, _storage.dateValue);
            break;

            /*
              Numbers whose values are equal need to hash to the same thing
              as well.  Note that Value::compare() promotes numeric values to
              their largest common form in order for comparisons to work.
              We must hash all numeric values as if they are doubles so that
              things like grouping work.  We don't know what values will come
              down the pipe later, but if we start out with int representations
              of a value, and later see double representations of it, they need
              to end up in the same buckets.
             */
        case NumberDouble:
        case NumberLong:
        case NumberInt: {
            const double dbl = getDouble();
            if (isNaN(dbl)) {
                boost::hash_combine(seed, numeric_limits<double>::quiet_NaN());
            }
            else {
                boost::hash_combine(seed, dbl);
            }
            break;
        }

        case jstOID:
            getOid().hash_combine(seed);
            break;

        case Code:
        case Symbol:
        case String: {
            StringData sd = getStringData();
            MurmurHash3_x86_32(sd.rawData(), sd.size(), seed, &seed);
            break;
        }

        case Object:
            getDocument().hash_combine(seed);
            break;

        case Array: {
            const vector<Value>& vec = getArray();
            for (size_t i=0; i < vec.size(); i++)
                vec[i].hash_combine(seed);
            break;
        }

        case DBRef:
            boost::hash_combine(seed, _storage.getDBRef()->ns);
            _storage.getDBRef()->oid.hash_combine(seed);
            break;


        case BinData: {
            StringData sd = getStringData();
            MurmurHash3_x86_32(sd.rawData(), sd.size(), seed, &seed);
            boost::hash_combine(seed, _storage.binDataType());
            break;
        }

        case RegEx: {
            StringData sd = getStringData();
            MurmurHash3_x86_32(sd.rawData(), sd.size(), seed, &seed);
            break;
        }

        case CodeWScope: {
            // SERVER-7804
            const char * code = _storage.getCodeWScope()->code.c_str();
            boost::hash_range(seed, code, (code + strlen(code)));
            // Not going to bother hashing scope. Too many edge cases. Will fall back to
            // Value::compare when code is same, so this is ok.
            break;
        }
        }
    }

    BSONType Value::getWidestNumeric(BSONType lType, BSONType rType) {
        if (lType == NumberDouble) {
            switch(rType) {
            case NumberDouble:
            case NumberLong:
            case NumberInt:
                return NumberDouble;

            default:
                break;
            }
        }
        else if (lType == NumberLong) {
            switch(rType) {
            case NumberDouble:
                return NumberDouble;

            case NumberLong:
            case NumberInt:
                return NumberLong;

            default:
                break;
            }
        }
        else if (lType == NumberInt) {
            switch(rType) {
            case NumberDouble:
                return NumberDouble;

            case NumberLong:
                return NumberLong;

            case NumberInt:
                return NumberInt;

            default:
                break;
            }
        }

        // Reachable, but callers must subsequently err out in this case.
        return Undefined;
    }

    size_t Value::getApproximateSize() const {
        switch(getType()) {
        case Code:
        case RegEx:
        case Symbol:
        case BinData:
        case String:
            return sizeof(Value) + (_storage.shortStr
                                        ? 0 // string stored inline, so no extra mem usage
                                        : sizeof(RCString) + _storage.getString().size());

        case Object:
            return sizeof(Value) + getDocument().getApproximateSize();

        case Array: {
            size_t size = sizeof(Value);
            size += sizeof(RCVector);
            const size_t n = getArray().size();
            for(size_t i = 0; i < n; ++i) {
                size += getArray()[i].getApproximateSize();
            }
            return size;
        }

        case CodeWScope:
            return sizeof(Value) + sizeof(RCCodeWScope) + _storage.getCodeWScope()->code.size()
                                                        + _storage.getCodeWScope()->scope.objsize();

        case DBRef:
            return sizeof(Value) + sizeof(RCDBRef) + _storage.getDBRef()->ns.size();

        // These types are always contained within the Value
        case EOO:
        case MinKey:
        case MaxKey:
        case NumberDouble:
        case jstOID:
        case Bool:
        case Date:
        case NumberInt:
        case Timestamp:
        case NumberLong:
        case jstNULL:
        case Undefined:
            return sizeof(Value);
        }
        verify(false);
    }

    string Value::toString() const {
        // TODO use StringBuilder when operator << is ready
        stringstream out;
        out << *this;
        return out.str();
    }

    ostream& operator << (ostream& out, const Value& val) {
        switch(val.getType()) {
        case EOO: return out << "MISSING";
        case MinKey: return out << "MinKey";
        case MaxKey: return out << "MaxKey";
        case jstOID: return out << val.getOid();
        case String: return out << '"' << val.getString() << '"';
        case RegEx: return out << '/' << val.getRegex() << '/' << val.getRegexFlags();
        case Symbol: return out << "Symbol(\"" << val.getSymbol() << "\")";
        case Code: return out << "Code(\"" << val.getCode() << "\")";
        case Bool: return out << (val.getBool() ? "true" : "false");
        case NumberDouble: return out << val.getDouble();
        case NumberLong: return out << val.getLong();
        case NumberInt: return out << val.getInt();
        case jstNULL: return out << "null";
        case Undefined: return out << "undefined";
        case Date: return out << tmToISODateString(val.coerceToTm());
        case Timestamp: return out << val.getTimestamp().toString();
        case Object: return out << val.getDocument().toString();
        case Array: {
            out << "[";
            const size_t n = val.getArray().size();
            for(size_t i = 0; i < n; i++) {
                if (i)
                    out << ", ";
                out << val.getArray()[i];
            }
            out << "]";
            return out;
        }

        case CodeWScope:
            return out << "CodeWScope(\"" << val._storage.getCodeWScope()->code << "\", "
                                          << val._storage.getCodeWScope()->scope << ')';

        case BinData: 
            return out << "BinData(" << val._storage.binDataType() << ", \""
                                     << toHex(val._storage.getString().rawData()
                                             ,val._storage.getString().size())
                                     << "\")";

        case DBRef:
            return out << "DBRef(\"" << val._storage.getDBRef()->ns << "\", "
                                     << val._storage.getDBRef()->oid << ')';
        }

        // Not in default case to trigger better warning if a case is missing
        verify(false);
    }

    void Value::serializeForSorter(BufBuilder& buf) const {
        buf.appendChar(getType());
        switch(getType()) {
        // type-only types
        case EOO:
        case MinKey:
        case MaxKey:
        case jstNULL:
        case Undefined:
            break;

        // simple types
        case jstOID:       buf.appendStruct(_storage.oid); break;
        case NumberInt:    buf.appendNum(_storage.intValue); break;
        case NumberLong:   buf.appendNum(_storage.longValue); break;
        case NumberDouble: buf.appendNum(_storage.doubleValue); break;
        case Bool:         buf.appendChar(_storage.boolValue); break;
        case Date:         buf.appendNum(_storage.dateValue); break;
        case Timestamp:    buf.appendStruct(getTimestamp()); break;

        // types that are like strings
        case String:
        case Symbol:
        case Code: {
            StringData str = getStringData();
            buf.appendNum(int(str.size()));
            buf.appendStr(str, /*NUL byte*/ false);
            break;
        }

        case BinData: {
            StringData str = getStringData();
            buf.appendChar(_storage.binDataType());
            buf.appendNum(int(str.size()));
            buf.appendStr(str, /*NUL byte*/ false);
            break;
        }

        case RegEx:
            buf.appendStr(getRegex(), /*NUL byte*/ true);
            buf.appendStr(getRegexFlags(), /*NUL byte*/ true);
            break;

        case Object:
            getDocument().serializeForSorter(buf);
            break;

        case DBRef:
            buf.appendStruct(_storage.getDBRef()->oid);
            buf.appendStr(_storage.getDBRef()->ns, /*NUL byte*/ true);
            break;

        case CodeWScope: {
            intrusive_ptr<const RCCodeWScope> cws = _storage.getCodeWScope();
            buf.appendNum(int(cws->code.size()));
            buf.appendStr(cws->code, /*NUL byte*/ false);
            cws->scope.serializeForSorter(buf);
            break;
         }

        case Array: {
            const vector<Value>& array = getArray();
            const int numElems = array.size();
            buf.appendNum(numElems);
            for (int i = 0; i < numElems; i++)
                array[i].serializeForSorter(buf);
            break;
        }
        }
    }

    Value Value::deserializeForSorter(BufReader& buf, const SorterDeserializeSettings& settings) {
        const BSONType type = BSONType(buf.read<signed char>()); // need sign extension for MinKey
        switch(type) {
        // type-only types
        case EOO:
        case MinKey:
        case MaxKey:
        case jstNULL:
        case Undefined:
            return Value(ValueStorage(type));

        // simple types
        case jstOID:       return Value(buf.read<OID>());
        case NumberInt:    return Value(buf.read<int>());
        case NumberLong:   return Value(buf.read<long long>());
        case NumberDouble: return Value(buf.read<double>());
        case Bool:         return Value(bool(buf.read<char>()));
        case Date:         return Value(Date_t(buf.read<long long>()));
        case Timestamp:    return Value(buf.read<OpTime>());

        // types that are like strings
        case String:
        case Symbol:
        case Code: {
            int size = buf.read<int>();
            const char* str = static_cast<const char*>(buf.skip(size));
            return Value(ValueStorage(type, StringData(str, size)));
        }

        case BinData: {
            BinDataType bdt = BinDataType(buf.read<char>());
            int size = buf.read<int>();
            const void* data = buf.skip(size);
            return Value(BSONBinData(data, size, bdt));
        }

        case RegEx: {
            StringData regex = buf.readCStr();
            StringData flags = buf.readCStr();
            return Value(BSONRegEx(regex, flags));
        }

        case Object:
            return Value(Document::deserializeForSorter(buf,
                                                        Document::SorterDeserializeSettings()));

        case DBRef: {
            OID oid = buf.read<OID>();
            StringData ns = buf.readCStr();
            return Value(BSONDBRef(ns, oid));
        }

        case CodeWScope: {
            int size = buf.read<int>();
            const char* str = static_cast<const char*>(buf.skip(size));
            BSONObj bson = BSONObj::deserializeForSorter(buf, BSONObj::SorterDeserializeSettings());
            return Value(BSONCodeWScope(StringData(str, size), bson));
         }

        case Array: {
            const int numElems = buf.read<int>();
            vector<Value> array;
            array.reserve(numElems);
            for (int i = 0; i < numElems; i++)
                array.push_back(deserializeForSorter(buf, settings));
            return Value::consume(array);
        }
        }
        verify(false);
    }
}