summaryrefslogtreecommitdiffstats
path: root/js/src/jsobj.h
blob: 01845d7e6cd6f8950ad91fdcf1b8954783625c71 (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
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef jsobj_h
#define jsobj_h

/*
 * JS object definitions.
 *
 * A JS object consists of a possibly-shared object descriptor containing
 * ordered property names, called the map; and a dense vector of property
 * values, called slots.  The map/slot pointer pair is GC'ed, while the map
 * is reference counted and the slot vector is malloc'ed.
 */

#include "mozilla/MemoryReporting.h"

#include "gc/Barrier.h"
#include "gc/Marking.h"
#include "js/Conversions.h"
#include "js/GCAPI.h"
#include "js/GCVector.h"
#include "js/HeapAPI.h"
#include "vm/Shape.h"
#include "vm/String.h"
#include "vm/Xdr.h"

namespace JS {
struct ClassInfo;
} // namespace JS

namespace js {

using PropertyDescriptorVector = JS::GCVector<JS::PropertyDescriptor>;
class GCMarker;
class Nursery;

namespace gc {
class RelocationOverlay;
} // namespace gc

inline JSObject*
CastAsObject(GetterOp op)
{
    return JS_FUNC_TO_DATA_PTR(JSObject*, op);
}

inline JSObject*
CastAsObject(SetterOp op)
{
    return JS_FUNC_TO_DATA_PTR(JSObject*, op);
}

inline Value
CastAsObjectJsval(GetterOp op)
{
    return ObjectOrNullValue(CastAsObject(op));
}

inline Value
CastAsObjectJsval(SetterOp op)
{
    return ObjectOrNullValue(CastAsObject(op));
}

/******************************************************************************/

extern const Class IntlClass;
extern const Class JSONClass;
extern const Class MathClass;

class GlobalObject;
class NewObjectCache;

enum class IntegrityLevel {
    Sealed,
    Frozen
};

// Forward declarations, required for later friend declarations.
bool PreventExtensions(JSContext* cx, JS::HandleObject obj, JS::ObjectOpResult& result, IntegrityLevel level = IntegrityLevel::Sealed);
bool SetImmutablePrototype(js::ExclusiveContext* cx, JS::HandleObject obj, bool* succeeded);

}  /* namespace js */

/*
 * A JavaScript object. The members common to all objects are as follows:
 *
 * - The |group_| member stores the group of the object, which contains its
 *   prototype object, its class and the possible types of its properties.
 *
 * Subclasses of JSObject --- mainly NativeObject and JSFunction --- add more
 * members. Notable among these is the object's shape, which stores flags and
 * some other state, and, for native objects, the layout of all its properties.
 * The second word of a JSObject generally stores its shape; if the second word
 * stores anything else, the value stored cannot be a valid Shape* pointer, so
 * that shape guards can be performed on objects without regard to the specific
 * layout in use.
 */
class JSObject : public js::gc::Cell
{
  protected:
    js::GCPtrObjectGroup group_;

  private:
    friend class js::Shape;
    friend class js::GCMarker;
    friend class js::NewObjectCache;
    friend class js::Nursery;
    friend class js::gc::RelocationOverlay;
    friend bool js::PreventExtensions(JSContext* cx, JS::HandleObject obj, JS::ObjectOpResult& result, js::IntegrityLevel level);
    friend bool js::SetImmutablePrototype(js::ExclusiveContext* cx, JS::HandleObject obj,
                                          bool* succeeded);

    // Make a new group to use for a singleton object.
    static js::ObjectGroup* makeLazyGroup(JSContext* cx, js::HandleObject obj);

  public:
    bool isNative() const {
        return getClass()->isNative();
    }

    const js::Class* getClass() const {
        return group_->clasp();
    }
    const JSClass* getJSClass() const {
        return Jsvalify(getClass());
    }
    bool hasClass(const js::Class* c) const {
        return getClass() == c;
    }

    js::LookupPropertyOp getOpsLookupProperty() const { return getClass()->getOpsLookupProperty(); }
    js::DefinePropertyOp getOpsDefineProperty() const { return getClass()->getOpsDefineProperty(); }
    js::HasPropertyOp    getOpsHasProperty()    const { return getClass()->getOpsHasProperty(); }
    js::GetPropertyOp    getOpsGetProperty()    const { return getClass()->getOpsGetProperty(); }
    js::SetPropertyOp    getOpsSetProperty()    const { return getClass()->getOpsSetProperty(); }
    js::GetOwnPropertyOp getOpsGetOwnPropertyDescriptor()
                                                const { return getClass()->getOpsGetOwnPropertyDescriptor(); }
    js::DeletePropertyOp getOpsDeleteProperty() const { return getClass()->getOpsDeleteProperty(); }
    js::GetElementsOp    getOpsGetElements()    const { return getClass()->getOpsGetElements(); }
    JSNewEnumerateOp     getOpsEnumerate()      const { return getClass()->getOpsEnumerate(); }
    JSFunToStringOp      getOpsFunToString()    const { return getClass()->getOpsFunToString(); }

    js::ObjectGroup* group() const {
        MOZ_ASSERT(!hasLazyGroup());
        return groupRaw();
    }

    js::ObjectGroup* groupRaw() const {
        return group_;
    }

    /*
     * Whether this is the only object which has its specified group. This
     * object will have its group constructed lazily as needed by analysis.
     */
    bool isSingleton() const {
        return group_->singleton();
    }

    /*
     * Whether the object's group has not been constructed yet. If an object
     * might have a lazy group, use getGroup() below, otherwise group().
     */
    bool hasLazyGroup() const {
        return group_->lazy();
    }

    JSCompartment* compartment() const { return group_->compartment(); }
    JSCompartment* maybeCompartment() const { return compartment(); }

    inline js::Shape* maybeShape() const;
    inline js::Shape* ensureShape(js::ExclusiveContext* cx);

    /*
     * Make a non-array object with the specified initial state. This method
     * takes ownership of any extantSlots it is passed.
     */
    static inline JSObject* create(js::ExclusiveContext* cx,
                                   js::gc::AllocKind kind,
                                   js::gc::InitialHeap heap,
                                   js::HandleShape shape,
                                   js::HandleObjectGroup group);

    // Set the initial slots and elements of an object. These pointers are only
    // valid for native objects, but during initialization are set for all
    // objects. For non-native objects, these must not be dynamically allocated
    // pointers which leak when the non-native object finishes initialization.
    inline void setInitialSlotsMaybeNonNative(js::HeapSlot* slots);
    inline void setInitialElementsMaybeNonNative(js::HeapSlot* elements);

    enum GenerateShape {
        GENERATE_NONE,
        GENERATE_SHAPE
    };

    static bool setFlags(js::ExclusiveContext* cx, JS::HandleObject obj, js::BaseShape::Flag flags,
                         GenerateShape generateShape = GENERATE_NONE);
    inline bool hasAllFlags(js::BaseShape::Flag flags) const;

    /*
     * An object is a delegate if it is on another object's prototype or scope
     * chain, and therefore the delegate might be asked implicitly to get or
     * set a property on behalf of another object. Delegates may be accessed
     * directly too, as may any object, but only those objects linked after the
     * head of any prototype or scope chain are flagged as delegates. This
     * definition helps to optimize shape-based property cache invalidation
     * (see Purge{Scope,Proto}Chain in jsobj.cpp).
     */
    inline bool isDelegate() const;
    static bool setDelegate(js::ExclusiveContext* cx, JS::HandleObject obj) {
        return setFlags(cx, obj, js::BaseShape::DELEGATE, GENERATE_SHAPE);
    }

    inline bool isBoundFunction() const;
    inline bool hasSpecialEquality() const;

    // A "qualified" varobj is the object on which "qualified" variable
    // declarations (i.e., those defined with "var") are kept.
    //
    // Conceptually, when a var binding is defined, it is defined on the
    // innermost qualified varobj on the scope chain.
    //
    // Function scopes (CallObjects) are qualified varobjs, and there can be
    // no other qualified varobj that is more inner for var bindings in that
    // function. As such, all references to local var bindings in a function
    // may be statically bound to the function scope. This is subject to
    // further optimization. Unaliased bindings inside functions reside
    // entirely on the frame, not in CallObjects.
    //
    // Global scopes are also qualified varobjs. It is possible to statically
    // know, for a given script, that are no more inner qualified varobjs, so
    // free variable references can be statically bound to the global.
    //
    // Finally, there are non-syntactic qualified varobjs used by embedders
    // (e.g., Gecko and XPConnect), as they often wish to run scripts under a
    // scope that captures var bindings.
    inline bool isQualifiedVarObj() const;
    static bool setQualifiedVarObj(js::ExclusiveContext* cx, JS::HandleObject obj) {
        return setFlags(cx, obj, js::BaseShape::QUALIFIED_VAROBJ);
    }

    // An "unqualified" varobj is the object on which "unqualified"
    // assignments (i.e., bareword assignments for which the LHS does not
    // exist on the scope chain) are kept.
    inline bool isUnqualifiedVarObj() const;

    // Objects with an uncacheable proto can have their prototype mutated
    // without inducing a shape change on the object. JIT inline caches should
    // do an explicit group guard to guard against this. Singletons always
    // generate a new shape when their prototype changes, regardless of this
    // hasUncacheableProto flag.
    inline bool hasUncacheableProto() const;
    static bool setUncacheableProto(js::ExclusiveContext* cx, JS::HandleObject obj) {
        MOZ_ASSERT(obj->hasStaticPrototype(),
                   "uncacheability as a concept is only applicable to static "
                   "(not dynamically-computed) prototypes");
        return setFlags(cx, obj, js::BaseShape::UNCACHEABLE_PROTO, GENERATE_SHAPE);
    }

    /*
     * Whether SETLELEM was used to access this object. See also the comment near
     * PropertyTree::MAX_HEIGHT.
     */
    inline bool hadElementsAccess() const;
    static bool setHadElementsAccess(js::ExclusiveContext* cx, JS::HandleObject obj) {
        return setFlags(cx, obj, js::BaseShape::HAD_ELEMENTS_ACCESS);
    }

    /*
     * Whether there may be indexed properties on this object, excluding any in
     * the object's elements.
     */
    inline bool isIndexed() const;

    /*
     * If this object was instantiated with `new Ctor`, return the constructor's
     * display atom. Otherwise, return nullptr.
     */
    static bool constructorDisplayAtom(JSContext* cx, js::HandleObject obj,
                                       js::MutableHandleAtom name);

    /*
     * The same as constructorDisplayAtom above, however if this object has a
     * lazy group, nullptr is returned. This allows for use in situations that
     * cannot GC and where having some information, even if it is inconsistently
     * available, is better than no information.
     */
    JSAtom* maybeConstructorDisplayAtom() const;

    /* GC support. */

    void traceChildren(JSTracer* trc);

    void fixupAfterMovingGC();

    static const JS::TraceKind TraceKind = JS::TraceKind::Object;
    static const size_t MaxTagBits = 3;
    static bool isNullLike(const JSObject* obj) { return uintptr_t(obj) < (1 << MaxTagBits); }

    MOZ_ALWAYS_INLINE JS::Zone* zone() const {
        return group_->zone();
    }
    MOZ_ALWAYS_INLINE JS::shadow::Zone* shadowZone() const {
        return JS::shadow::Zone::asShadowZone(zone());
    }
    MOZ_ALWAYS_INLINE JS::Zone* zoneFromAnyThread() const {
        return group_->zoneFromAnyThread();
    }
    MOZ_ALWAYS_INLINE JS::shadow::Zone* shadowZoneFromAnyThread() const {
        return JS::shadow::Zone::asShadowZone(zoneFromAnyThread());
    }
    static MOZ_ALWAYS_INLINE void readBarrier(JSObject* obj);
    static MOZ_ALWAYS_INLINE void writeBarrierPre(JSObject* obj);
    static MOZ_ALWAYS_INLINE void writeBarrierPost(void* cellp, JSObject* prev, JSObject* next);

    /* Return the allocKind we would use if we were to tenure this object. */
    js::gc::AllocKind allocKindForTenure(const js::Nursery& nursery) const;

    size_t tenuredSizeOfThis() const {
        MOZ_ASSERT(isTenured());
        return js::gc::Arena::thingSize(asTenured().getAllocKind());
    }

    void addSizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf, JS::ClassInfo* info);

    // We can only use addSizeOfExcludingThis on tenured objects: it assumes it
    // can apply mallocSizeOf to bits and pieces of the object, whereas objects
    // in the nursery may have those bits and pieces allocated in the nursery
    // along with them, and are not each their own malloc blocks.
    size_t sizeOfIncludingThisInNursery() const;

    // Marks this object as having a singleton group, and leave the group lazy.
    // Constructs a new, unique shape for the object. This should only be
    // called for an object that was just created.
    static inline bool setSingleton(js::ExclusiveContext* cx, js::HandleObject obj);

    // Change an existing object to have a singleton group.
    static bool changeToSingleton(JSContext* cx, js::HandleObject obj);

    static inline js::ObjectGroup* getGroup(JSContext* cx, js::HandleObject obj);

    const js::GCPtrObjectGroup& groupFromGC() const {
        /* Direct field access for use by GC. */
        return group_;
    }

    /*
     * We permit proxies to dynamically compute their prototype if desired.
     * (Not all proxies will so desire: in particular, most DOM proxies can
     * track their prototype with a single, nullable JSObject*.)  If a proxy
     * so desires, we store (JSObject*)0x1 in the proto field of the object's
     * group.
     *
     * We offer three ways to get an object's prototype:
     *
     * 1. obj->staticPrototype() returns the prototype, but it asserts if obj
     *    is a proxy, and the proxy has opted to dynamically compute its
     *    prototype using a getPrototype() handler.
     * 2. obj->taggedProto() returns a TaggedProto, which can be tested to
     *    check if the proto is an object, nullptr, or lazily computed.
     * 3. js::GetPrototype(cx, obj, &proto) computes the proto of an object.
     *    If obj is a proxy with dynamically-computed prototype, this code may
     *    perform arbitrary behavior (allocation, GC, run JS) while computing
     *    the proto.
     */

    js::TaggedProto taggedProto() const {
        return group_->proto();
    }

    bool hasTenuredProto() const;

    bool uninlinedIsProxy() const;

    JSObject* staticPrototype() const {
        MOZ_ASSERT(hasStaticPrototype());
        return taggedProto().toObjectOrNull();
    }

    // Normal objects and a subset of proxies have an uninteresting, static
    // (albeit perhaps mutable) [[Prototype]].  For such objects the
    // [[Prototype]] is just a value returned when needed for accesses, or
    // modified in response to requests.  These objects store the
    // [[Prototype]] directly within |obj->group_|.
    bool hasStaticPrototype() const {
        return !hasDynamicPrototype();
    }

    // The remaining proxies have a [[Prototype]] requiring dynamic computation
    // for every access, going through the proxy handler {get,set}Prototype and
    // setImmutablePrototype methods.  (Wrappers particularly use this to keep
    // the wrapper/wrappee [[Prototype]]s consistent.)
    bool hasDynamicPrototype() const {
        bool dynamic = taggedProto().isDynamic();
        MOZ_ASSERT_IF(dynamic, uninlinedIsProxy());
        MOZ_ASSERT_IF(dynamic, !isNative());
        return dynamic;
    }

    // True iff this object's [[Prototype]] is immutable.  Must be called only
    // on objects with a static [[Prototype]]!
    inline bool staticPrototypeIsImmutable() const;

    inline void setGroup(js::ObjectGroup* group);

    /*
     * Mark an object that has been iterated over and is a singleton. We need
     * to recover this information in the object's type information after it
     * is purged on GC.
     */
    inline bool isIteratedSingleton() const;
    static bool setIteratedSingleton(js::ExclusiveContext* cx, JS::HandleObject obj) {
        return setFlags(cx, obj, js::BaseShape::ITERATED_SINGLETON);
    }

    /*
     * Mark an object as requiring its default 'new' type to have unknown
     * properties.
     */
    inline bool isNewGroupUnknown() const;
    static bool setNewGroupUnknown(JSContext* cx, const js::Class* clasp, JS::HandleObject obj);

    // Mark an object as having its 'new' script information cleared.
    inline bool wasNewScriptCleared() const;
    static bool setNewScriptCleared(js::ExclusiveContext* cx, JS::HandleObject obj) {
        return setFlags(cx, obj, js::BaseShape::NEW_SCRIPT_CLEARED);
    }

    /* Set a new prototype for an object with a singleton type. */
    static bool splicePrototype(JSContext* cx, js::HandleObject obj, const js::Class* clasp,
                                js::Handle<js::TaggedProto> proto);

    /*
     * For bootstrapping, whether to splice a prototype for Function.prototype
     * or the global object.
     */
    bool shouldSplicePrototype();

    /*
     * Environment chains.
     *
     * The environment chain of an object is the link in the search path when
     * a script does a name lookup on an environment object. For JS internal
     * environment objects --- Call, LexicalEnvironment, and WithEnvironment
     * --- the chain is stored in the first fixed slot of the object.  For
     * other environment objects, the chain goes directly to the global.
     *
     * In code which is not marked hasNonSyntacticScope, environment chains
     * can contain only syntactic environment objects (see
     * IsSyntacticEnvironment) with a global object at the root as the
     * environment of the outermost non-function script. In
     * hasNonSyntacticScope code, the environment of the outermost
     * non-function script might not be a global object, and can have a mix of
     * other objects above it before the global object is reached.
     */

    /*
     * Get the enclosing environment of an object. When called on a
     * non-EnvironmentObject, this will just be the global (the name
     * "enclosing environment" still applies in this situation because
     * non-EnvironmentObjects can be on the environment chain).
     */
    inline JSObject* enclosingEnvironment() const;

    inline js::GlobalObject& global() const;

    // In some rare cases the global object's compartment's global may not be
    // the same global object. For this reason, we need to take extra care when
    // tracing.
    //
    // These cases are:
    //  1) The off-thread parsing task uses a dummy global since it cannot
    //     share with the actual global being used concurrently on the main
    //     thread.
    //  2) A GC may occur when creating the GlobalObject, in which case the
    //     compartment global pointer may not yet be set. In this case there is
    //     nothing interesting to trace in the compartment.
    inline bool isOwnGlobal(JSTracer*) const;
    inline js::GlobalObject* globalForTracing(JSTracer*) const;

    /*
     * ES5 meta-object properties and operations.
     */

  public:
    // Indicates whether a non-proxy is extensible.  Don't call on proxies!
    // This method really shouldn't exist -- but there are a few internal
    // places that want it (JITs and the like), and it'd be a pain to mark them
    // all as friends.
    inline bool nonProxyIsExtensible() const;

  public:
    /*
     * Iterator-specific getters and setters.
     */

    static const uint32_t ITER_CLASS_NFIXED_SLOTS = 1;

    /*
     * Back to generic stuff.
     */
    bool isCallable() const;
    bool isConstructor() const;
    JSNative callHook() const;
    JSNative constructHook() const;

    MOZ_ALWAYS_INLINE void finalize(js::FreeOp* fop);

  public:
    static bool reportReadOnly(JSContext* cx, jsid id, unsigned report = JSREPORT_ERROR);
    static bool reportNotConfigurable(JSContext* cx, jsid id, unsigned report = JSREPORT_ERROR);
    static bool reportNotExtensible(JSContext* cx, js::HandleObject obj,
                                    unsigned report = JSREPORT_ERROR);

    static bool nonNativeSetProperty(JSContext* cx, js::HandleObject obj, js::HandleId id,
                                     js::HandleValue v, js::HandleValue receiver,
                                     JS::ObjectOpResult& result);
    static bool nonNativeSetElement(JSContext* cx, js::HandleObject obj, uint32_t index,
                                    js::HandleValue v, js::HandleValue receiver,
                                    JS::ObjectOpResult& result);

    static bool swap(JSContext* cx, JS::HandleObject a, JS::HandleObject b);

  private:
    void fixDictionaryShapeAfterSwap();

  public:
    inline void initArrayClass();

    /*
     * In addition to the generic object interface provided by JSObject,
     * specific types of objects may provide additional operations. To access,
     * these addition operations, callers should use the pattern:
     *
     *   if (obj.is<XObject>()) {
     *     XObject& x = obj.as<XObject>();
     *     x.foo();
     *   }
     *
     * These XObject classes form a hierarchy. For example, for a cloned block
     * object, the following predicates are true: is<ClonedBlockObject>,
     * is<NestedScopeObject> and is<ScopeObject>. Each of these has a
     * respective class that derives and adds operations.
     *
     * A class XObject is defined in a vm/XObject{.h, .cpp, -inl.h} file
     * triplet (along with any class YObject that derives XObject).
     *
     * Note that X represents a low-level representation and does not query the
     * [[Class]] property of object defined by the spec (for this, see
     * js::GetBuiltinClass).
     */

    template <class T>
    inline bool is() const { return getClass() == &T::class_; }

    template <class T>
    T& as() {
        MOZ_ASSERT(this->is<T>());
        return *static_cast<T*>(this);
    }

    template <class T>
    const T& as() const {
        MOZ_ASSERT(this->is<T>());
        return *static_cast<const T*>(this);
    }

#ifdef DEBUG
    void dump(FILE* fp) const;
    void dump() const;
#endif

    /* JIT Accessors */

    static size_t offsetOfGroup() { return offsetof(JSObject, group_); }

    // Maximum size in bytes of a JSObject.
    static const size_t MAX_BYTE_SIZE = 4 * sizeof(void*) + 16 * sizeof(JS::Value);

  private:
    JSObject() = delete;
    JSObject(const JSObject& other) = delete;
    void operator=(const JSObject& other) = delete;
};

template <class U>
MOZ_ALWAYS_INLINE JS::Handle<U*>
js::RootedBase<JSObject*>::as() const
{
    const JS::Rooted<JSObject*>& self = *static_cast<const JS::Rooted<JSObject*>*>(this);
    MOZ_ASSERT(self->is<U>());
    return Handle<U*>::fromMarkedLocation(reinterpret_cast<U* const*>(self.address()));
}

template <class U>
MOZ_ALWAYS_INLINE JS::Handle<U*>
js::HandleBase<JSObject*>::as() const
{
    const JS::Handle<JSObject*>& self = *static_cast<const JS::Handle<JSObject*>*>(this);
    MOZ_ASSERT(self->is<U>());
    return Handle<U*>::fromMarkedLocation(reinterpret_cast<U* const*>(self.address()));
}

/*
 * The only sensible way to compare JSObject with == is by identity. We use
 * const& instead of * as a syntactic way to assert non-null. This leads to an
 * abundance of address-of operators to identity. Hence this overload.
 */
static MOZ_ALWAYS_INLINE bool
operator==(const JSObject& lhs, const JSObject& rhs)
{
    return &lhs == &rhs;
}

static MOZ_ALWAYS_INLINE bool
operator!=(const JSObject& lhs, const JSObject& rhs)
{
    return &lhs != &rhs;
}

// Size of the various GC thing allocation sizes used for objects.
struct JSObject_Slots0 : JSObject { void* data[3]; };
struct JSObject_Slots2 : JSObject { void* data[3]; js::Value fslots[2]; };
struct JSObject_Slots4 : JSObject { void* data[3]; js::Value fslots[4]; };
struct JSObject_Slots8 : JSObject { void* data[3]; js::Value fslots[8]; };
struct JSObject_Slots12 : JSObject { void* data[3]; js::Value fslots[12]; };
struct JSObject_Slots16 : JSObject { void* data[3]; js::Value fslots[16]; };

/* static */ MOZ_ALWAYS_INLINE void
JSObject::readBarrier(JSObject* obj)
{
    MOZ_ASSERT_IF(obj, !isNullLike(obj));
    if (obj && obj->isTenured())
        obj->asTenured().readBarrier(&obj->asTenured());
}

/* static */ MOZ_ALWAYS_INLINE void
JSObject::writeBarrierPre(JSObject* obj)
{
    MOZ_ASSERT_IF(obj, !isNullLike(obj));
    if (obj && obj->isTenured())
        obj->asTenured().writeBarrierPre(&obj->asTenured());
}

/* static */ MOZ_ALWAYS_INLINE void
JSObject::writeBarrierPost(void* cellp, JSObject* prev, JSObject* next)
{
    MOZ_ASSERT(cellp);
    MOZ_ASSERT_IF(next, !IsNullTaggedPointer(next));
    MOZ_ASSERT_IF(prev, !IsNullTaggedPointer(prev));

    // If the target needs an entry, add it.
    js::gc::StoreBuffer* buffer;
    if (next && (buffer = next->storeBuffer())) {
        // If we know that the prev has already inserted an entry, we can skip
        // doing the lookup to add the new entry. Note that we cannot safely
        // assert the presence of the entry because it may have been added
        // via a different store buffer.
        if (prev && prev->storeBuffer())
            return;
        buffer->putCell(static_cast<js::gc::Cell**>(cellp));
        return;
    }

    // Remove the prev entry if the new value does not need it.
    if (prev && (buffer = prev->storeBuffer()))
        buffer->unputCell(static_cast<js::gc::Cell**>(cellp));
}

namespace js {

inline bool
IsCallable(const Value& v)
{
    return v.isObject() && v.toObject().isCallable();
}

// ES6 rev 24 (2014 April 27) 7.2.5 IsConstructor
inline bool
IsConstructor(const Value& v)
{
    return v.isObject() && v.toObject().isConstructor();
}

} /* namespace js */

class JSValueArray {
  public:
    const js::Value* array;
    size_t length;

    JSValueArray(const js::Value* v, size_t c) : array(v), length(c) {}
};

class ValueArray {
  public:
    js::Value* array;
    size_t length;

    ValueArray(js::Value* v, size_t c) : array(v), length(c) {}
};

namespace js {

/*** Standard internal methods ********************************************************************
 *
 * The functions below are the fundamental operations on objects. See the
 * comment about "Standard internal methods" in jsapi.h.
 */

/*
 * ES6 [[GetPrototypeOf]]. Get obj's prototype, storing it in protop.
 *
 * If obj is definitely not a proxy, the infallible obj->getProto() can be used
 * instead. See the comment on JSObject::getTaggedProto().
 */
inline bool
GetPrototype(JSContext* cx, HandleObject obj, MutableHandleObject protop);

/*
 * ES6 [[SetPrototypeOf]]. Change obj's prototype to proto.
 *
 * Returns false on error, success of operation in *result. For example, if
 * obj is not extensible, its prototype is fixed. js::SetPrototype will return
 * true, because no exception is thrown for this; but *result will be false.
 */
extern bool
SetPrototype(JSContext* cx, HandleObject obj, HandleObject proto,
             ObjectOpResult& result);

/* Convenience function: like the above, but throw on failure. */
extern bool
SetPrototype(JSContext* cx, HandleObject obj, HandleObject proto);

/*
 * ES6 [[IsExtensible]]. Extensible objects can have new properties defined on
 * them. Inextensible objects can't, and their [[Prototype]] slot is fixed as
 * well.
 */
inline bool
IsExtensible(ExclusiveContext* cx, HandleObject obj, bool* extensible);

/*
 * ES6 [[PreventExtensions]]. Attempt to change the [[Extensible]] bit on |obj|
 * to false.  Indicate success or failure through the |result| outparam, or
 * actual error through the return value.
 *
 * The `level` argument is SM-specific. `obj` should have an integrity level of
 * at least `level`.
 */
extern bool
PreventExtensions(JSContext* cx, HandleObject obj, ObjectOpResult& result, IntegrityLevel level);

/* Convenience function. As above, but throw on failure. */
extern bool
PreventExtensions(JSContext* cx, HandleObject obj, IntegrityLevel level = IntegrityLevel::Sealed);

/*
 * ES6 [[GetOwnProperty]]. Get a description of one of obj's own properties.
 *
 * If no such property exists on obj, return true with desc.object() set to
 * null.
 */
extern bool
GetOwnPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id,
                         MutableHandle<JS::PropertyDescriptor> desc);

/* ES6 [[DefineOwnProperty]]. Define a property on obj. */
extern bool
DefineProperty(JSContext* cx, HandleObject obj, HandleId id,
               Handle<JS::PropertyDescriptor> desc, ObjectOpResult& result);

extern bool
DefineProperty(ExclusiveContext* cx, HandleObject obj, HandleId id, HandleValue value,
               JSGetterOp getter, JSSetterOp setter, unsigned attrs, ObjectOpResult& result);

extern bool
DefineProperty(ExclusiveContext* cx, HandleObject obj, PropertyName* name, HandleValue value,
               JSGetterOp getter, JSSetterOp setter, unsigned attrs, ObjectOpResult& result);

extern bool
DefineElement(ExclusiveContext* cx, HandleObject obj, uint32_t index, HandleValue value,
              JSGetterOp getter, JSSetterOp setter, unsigned attrs, ObjectOpResult& result);

/*
 * When the 'result' out-param is omitted, the behavior is the same as above, except
 * that any failure results in a TypeError.
 */
extern bool
DefineProperty(JSContext* cx, HandleObject obj, HandleId id, Handle<JS::PropertyDescriptor> desc);

extern bool
DefineProperty(ExclusiveContext* cx, HandleObject obj, HandleId id, HandleValue value,
               JSGetterOp getter = nullptr,
               JSSetterOp setter = nullptr,
               unsigned attrs = JSPROP_ENUMERATE);

extern bool
DefineProperty(ExclusiveContext* cx, HandleObject obj, PropertyName* name, HandleValue value,
               JSGetterOp getter = nullptr,
               JSSetterOp setter = nullptr,
               unsigned attrs = JSPROP_ENUMERATE);

extern bool
DefineElement(ExclusiveContext* cx, HandleObject obj, uint32_t index, HandleValue value,
              JSGetterOp getter = nullptr,
              JSSetterOp setter = nullptr,
              unsigned attrs = JSPROP_ENUMERATE);

/*
 * ES6 [[Has]]. Set *foundp to true if `id in obj` (that is, if obj has an own
 * or inherited property obj[id]), false otherwise.
 */
inline bool
HasProperty(JSContext* cx, HandleObject obj, HandleId id, bool* foundp);

inline bool
HasProperty(JSContext* cx, HandleObject obj, PropertyName* name, bool* foundp);

/*
 * ES6 [[Get]]. Get the value of the property `obj[id]`, or undefined if no
 * such property exists.
 *
 * Typically obj == receiver; if obj != receiver then the caller is most likely
 * a proxy using GetProperty to finish a property get that started out as
 * `receiver[id]`, and we've already searched the prototype chain up to `obj`.
 */
inline bool
GetProperty(JSContext* cx, HandleObject obj, HandleValue receiver, HandleId id,
            MutableHandleValue vp);

inline bool
GetProperty(JSContext* cx, HandleObject obj, HandleValue receiver, PropertyName* name,
            MutableHandleValue vp)
{
    RootedId id(cx, NameToId(name));
    return GetProperty(cx, obj, receiver, id, vp);
}

inline bool
GetProperty(JSContext* cx, HandleObject obj, HandleObject receiver, HandleId id,
            MutableHandleValue vp)
{
    RootedValue receiverValue(cx, ObjectValue(*receiver));
    return GetProperty(cx, obj, receiverValue, id, vp);
}

inline bool
GetProperty(JSContext* cx, HandleObject obj, HandleObject receiver, PropertyName* name,
            MutableHandleValue vp)
{
    RootedValue receiverValue(cx, ObjectValue(*receiver));
    return GetProperty(cx, obj, receiverValue, name, vp);
}

inline bool
GetElement(JSContext* cx, HandleObject obj, HandleValue receiver, uint32_t index,
           MutableHandleValue vp);

inline bool
GetElement(JSContext* cx, HandleObject obj, HandleObject receiver, uint32_t index,
           MutableHandleValue vp);

inline bool
GetPropertyNoGC(JSContext* cx, JSObject* obj, const Value& receiver, jsid id, Value* vp);

inline bool
GetPropertyNoGC(JSContext* cx, JSObject* obj, JSObject* receiver, jsid id, Value* vp)
{
    return GetPropertyNoGC(cx, obj, ObjectValue(*receiver), id, vp);
}

inline bool
GetPropertyNoGC(JSContext* cx, JSObject* obj, const Value& receiver, PropertyName* name, Value* vp)
{
    return GetPropertyNoGC(cx, obj, receiver, NameToId(name), vp);
}

inline bool
GetPropertyNoGC(JSContext* cx, JSObject* obj, JSObject* receiver, PropertyName* name, Value* vp)
{
    return GetPropertyNoGC(cx, obj, ObjectValue(*receiver), name, vp);
}

inline bool
GetElementNoGC(JSContext* cx, JSObject* obj, const Value& receiver, uint32_t index, Value* vp);

inline bool
GetElementNoGC(JSContext* cx, JSObject* obj, JSObject* receiver, uint32_t index, Value* vp);

/*
 * ES6 [[Set]]. Carry out the assignment `obj[id] = v`.
 *
 * The `receiver` argument has to do with how [[Set]] interacts with the
 * prototype chain and proxies. It's hard to explain and ES6 doesn't really
 * try. Long story short, if you just want bog-standard assignment, pass
 * `ObjectValue(*obj)` as receiver. Or better, use one of the signatures that
 * doesn't have a receiver parameter.
 *
 * Callers pass obj != receiver e.g. when a proxy is involved, obj is the
 * proxy's target, and the proxy is using SetProperty to finish an assignment
 * that started out as `receiver[id] = v`, by delegating it to obj.
 */
inline bool
SetProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v,
            HandleValue receiver, ObjectOpResult& result);

inline bool
SetProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v)
{
    RootedValue receiver(cx, ObjectValue(*obj));
    ObjectOpResult result;
    return SetProperty(cx, obj, id, v, receiver, result) &&
           result.checkStrict(cx, obj, id);
}

inline bool
SetProperty(JSContext* cx, HandleObject obj, PropertyName* name, HandleValue v,
            HandleValue receiver, ObjectOpResult& result)
{
    RootedId id(cx, NameToId(name));
    return SetProperty(cx, obj, id, v, receiver, result);
}

inline bool
SetProperty(JSContext* cx, HandleObject obj, PropertyName* name, HandleValue v)
{
    RootedId id(cx, NameToId(name));
    RootedValue receiver(cx, ObjectValue(*obj));
    ObjectOpResult result;
    return SetProperty(cx, obj, id, v, receiver, result) &&
           result.checkStrict(cx, obj, id);
}

inline bool
SetElement(JSContext* cx, HandleObject obj, uint32_t index, HandleValue v,
           HandleValue receiver, ObjectOpResult& result);

/*
 * ES6 draft rev 31 (15 Jan 2015) 7.3.3 Put (O, P, V, Throw), except that on
 * success, the spec says this is supposed to return a boolean value, which we
 * don't bother doing.
 */
inline bool
PutProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v, bool strict)
{
    RootedValue receiver(cx, ObjectValue(*obj));
    ObjectOpResult result;
    return SetProperty(cx, obj, id, v, receiver, result) &&
           result.checkStrictErrorOrWarning(cx, obj, id, strict);
}

/*
 * ES6 [[Delete]]. Equivalent to the JS code `delete obj[id]`.
 */
inline bool
DeleteProperty(JSContext* cx, HandleObject obj, HandleId id, ObjectOpResult& result);

inline bool
DeleteElement(JSContext* cx, HandleObject obj, uint32_t index, ObjectOpResult& result);


/*** SpiderMonkey nonstandard internal methods ***************************************************/

/**
 * If |obj| (underneath any functionally-transparent wrapper proxies) has as
 * its [[GetPrototypeOf]] trap the ordinary [[GetPrototypeOf]] behavior defined
 * for ordinary objects, set |*isOrdinary = true| and store |obj|'s prototype
 * in |result|.  Otherwise set |*isOrdinary = false|.  In case of error, both
 * outparams have unspecified value.
 */
extern bool
GetPrototypeIfOrdinary(JSContext* cx, HandleObject obj, bool* isOrdinary,
                       MutableHandleObject protop);

/*
 * Attempt to make |obj|'s [[Prototype]] immutable, such that subsequently
 * trying to change it will not work.  If an internal error occurred,
 * returns false.  Otherwise, |*succeeded| is set to true iff |obj|'s
 * [[Prototype]] is now immutable.
 */
extern bool
SetImmutablePrototype(js::ExclusiveContext* cx, JS::HandleObject obj, bool* succeeded);

extern bool
GetPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id,
                      MutableHandle<JS::PropertyDescriptor> desc);

/*
 * Deprecated. A version of HasProperty that also returns the object on which
 * the property was found (but that information is unreliable for proxies), and
 * the Shape of the property, if native.
 */
extern bool
LookupProperty(JSContext* cx, HandleObject obj, HandleId id,
               MutableHandleObject objp, MutableHandleShape propp);

inline bool
LookupProperty(JSContext* cx, HandleObject obj, PropertyName* name,
               MutableHandleObject objp, MutableHandleShape propp)
{
    RootedId id(cx, NameToId(name));
    return LookupProperty(cx, obj, id, objp, propp);
}

/* Set *result to tell whether obj has an own property with the given id. */
extern bool
HasOwnProperty(JSContext* cx, HandleObject obj, HandleId id, bool* result);

/**
 * This enum is used to select whether the defined functions should be marked as
 * builtin native instrinsics for self-hosted code.
 */
enum DefineAsIntrinsic {
    NotIntrinsic,
    AsIntrinsic
};

extern bool
DefineFunctions(JSContext* cx, HandleObject obj, const JSFunctionSpec* fs,
                DefineAsIntrinsic intrinsic);

/* ES6 draft rev 36 (2015 March 17) 7.1.1 ToPrimitive(vp[, preferredType]) */
extern bool
ToPrimitiveSlow(JSContext* cx, JSType hint, MutableHandleValue vp);

inline bool
ToPrimitive(JSContext* cx, MutableHandleValue vp)
{
    if (vp.isPrimitive())
        return true;
    return ToPrimitiveSlow(cx, JSTYPE_VOID, vp);
}

inline bool
ToPrimitive(JSContext* cx, JSType preferredType, MutableHandleValue vp)
{
    if (vp.isPrimitive())
        return true;
    return ToPrimitiveSlow(cx, preferredType, vp);
}

/*
 * toString support. (This isn't called GetClassName because there's a macro in
 * <windows.h> with that name.)
 */
extern const char*
GetObjectClassName(JSContext* cx, HandleObject obj);

/*
 * Return an object that may be used as `this` in place of obj. For most
 * objects this just returns obj.
 *
 * Some JSObjects shouldn't be exposed directly to script. This includes (at
 * least) WithEnvironmentObjects and Window objects. However, since both of
 * those can be on scope chains, we sometimes would expose those as `this` if
 * we were not so vigilant about calling GetThisValue where appropriate.
 *
 * See comments at ComputeImplicitThis.
 */
Value
GetThisValue(JSObject* obj);

/* * */

typedef JSObject* (*ClassInitializerOp)(JSContext* cx, JS::HandleObject obj);

/* Fast access to builtin constructors and prototypes. */
bool
GetBuiltinConstructor(ExclusiveContext* cx, JSProtoKey key, MutableHandleObject objp);

bool
GetBuiltinPrototype(ExclusiveContext* cx, JSProtoKey key, MutableHandleObject objp);

JSObject*
GetBuiltinPrototypePure(GlobalObject* global, JSProtoKey protoKey);

extern bool
SetClassAndProto(JSContext* cx, HandleObject obj,
                 const Class* clasp, Handle<TaggedProto> proto);

extern bool
IsStandardPrototype(JSObject* obj, JSProtoKey key);

} /* namespace js */

/*
 * Select Object.prototype method names shared between jsapi.cpp and jsobj.cpp.
 */
extern const char js_watch_str[];
extern const char js_unwatch_str[];
extern const char js_hasOwnProperty_str[];
extern const char js_isPrototypeOf_str[];
extern const char js_propertyIsEnumerable_str[];

#ifdef JS_OLD_GETTER_SETTER_METHODS
extern const char js_defineGetter_str[];
extern const char js_defineSetter_str[];
extern const char js_lookupGetter_str[];
extern const char js_lookupSetter_str[];
#endif

namespace js {

inline gc::InitialHeap
GetInitialHeap(NewObjectKind newKind, const Class* clasp)
{
    if (newKind == NurseryAllocatedProxy) {
        MOZ_ASSERT(clasp->isProxy());
        MOZ_ASSERT(clasp->hasFinalize());
        MOZ_ASSERT(!CanNurseryAllocateFinalizedClass(clasp));
        return gc::DefaultHeap;
    }
    if (newKind != GenericObject)
        return gc::TenuredHeap;
    if (clasp->hasFinalize() && !CanNurseryAllocateFinalizedClass(clasp))
        return gc::TenuredHeap;
    return gc::DefaultHeap;
}

bool
NewObjectWithTaggedProtoIsCachable(ExclusiveContext* cxArg, Handle<TaggedProto> proto,
                                   NewObjectKind newKind, const Class* clasp);

// ES6 9.1.15 GetPrototypeFromConstructor.
extern bool
GetPrototypeFromConstructor(JSContext* cx, js::HandleObject newTarget, js::MutableHandleObject proto);

extern bool
GetPrototypeFromCallableConstructor(JSContext* cx, const CallArgs& args, js::MutableHandleObject proto);

// Specialized call for constructing |this| with a known function callee,
// and a known prototype.
extern JSObject*
CreateThisForFunctionWithProto(JSContext* cx, js::HandleObject callee, HandleObject newTarget,
                               HandleObject proto, NewObjectKind newKind = GenericObject);

// Specialized call for constructing |this| with a known function callee.
extern JSObject*
CreateThisForFunction(JSContext* cx, js::HandleObject callee, js::HandleObject newTarget,
                      NewObjectKind newKind);

// Generic call for constructing |this|.
extern JSObject*
CreateThis(JSContext* cx, const js::Class* clasp, js::HandleObject callee);

extern JSObject*
CloneObject(JSContext* cx, HandleObject obj, Handle<js::TaggedProto> proto);

extern JSObject*
DeepCloneObjectLiteral(JSContext* cx, HandleObject obj, NewObjectKind newKind = GenericObject);

inline JSGetterOp
CastAsGetterOp(JSObject* object)
{
    return JS_DATA_TO_FUNC_PTR(JSGetterOp, object);
}

inline JSSetterOp
CastAsSetterOp(JSObject* object)
{
    return JS_DATA_TO_FUNC_PTR(JSSetterOp, object);
}

/* ES6 draft rev 32 (2015 Feb 2) 6.2.4.5 ToPropertyDescriptor(Obj) */
bool
ToPropertyDescriptor(JSContext* cx, HandleValue descval, bool checkAccessors,
                     MutableHandle<JS::PropertyDescriptor> desc);

/*
 * Throw a TypeError if desc.getterObject() or setterObject() is not
 * callable. This performs exactly the checks omitted by ToPropertyDescriptor
 * when checkAccessors is false.
 */
bool
CheckPropertyDescriptorAccessors(JSContext* cx, Handle<JS::PropertyDescriptor> desc);

void
CompletePropertyDescriptor(MutableHandle<JS::PropertyDescriptor> desc);

/*
 * Read property descriptors from props, as for Object.defineProperties. See
 * ES5 15.2.3.7 steps 3-5.
 */
extern bool
ReadPropertyDescriptors(JSContext* cx, HandleObject props, bool checkAccessors,
                        AutoIdVector* ids, MutableHandle<PropertyDescriptorVector> descs);

/* Read the name using a dynamic lookup on the scopeChain. */
extern bool
LookupName(JSContext* cx, HandlePropertyName name, HandleObject scopeChain,
           MutableHandleObject objp, MutableHandleObject pobjp, MutableHandleShape propp);

extern bool
LookupNameNoGC(JSContext* cx, PropertyName* name, JSObject* scopeChain,
               JSObject** objp, JSObject** pobjp, Shape** propp);

/*
 * Like LookupName except returns the global object if 'name' is not found in
 * any preceding scope.
 *
 * Additionally, pobjp and propp are not needed by callers so they are not
 * returned.
 */
extern bool
LookupNameWithGlobalDefault(JSContext* cx, HandlePropertyName name, HandleObject scopeChain,
                            MutableHandleObject objp);

/*
 * Like LookupName except returns the unqualified var object if 'name' is not
 * found in any preceding scope. Normally the unqualified var object is the
 * global. If the value for the name in the looked-up scope is an
 * uninitialized lexical, an UninitializedLexicalObject is returned.
 *
 * Additionally, pobjp is not needed by callers so it is not returned.
 */
extern bool
LookupNameUnqualified(JSContext* cx, HandlePropertyName name, HandleObject scopeChain,
                      MutableHandleObject objp);

} // namespace js

namespace js {

extern JSObject*
FindVariableScope(JSContext* cx, JSFunction** funp);

bool
LookupPropertyPure(ExclusiveContext* cx, JSObject* obj, jsid id, JSObject** objp,
                   Shape** propp);

bool
LookupOwnPropertyPure(ExclusiveContext* cx, JSObject* obj, jsid id, Shape** propp,
                      bool* isTypedArrayOutOfRange = nullptr);

bool
GetPropertyPure(ExclusiveContext* cx, JSObject* obj, jsid id, Value* vp);

bool
GetGetterPure(ExclusiveContext* cx, JSObject* obj, jsid id, JSFunction** fp);

bool
GetOwnGetterPure(ExclusiveContext* cx, JSObject* obj, jsid id, JSFunction** fp);

bool
GetOwnNativeGetterPure(JSContext* cx, JSObject* obj, jsid id, JSNative* native);

bool
HasOwnDataPropertyPure(JSContext* cx, JSObject* obj, jsid id, bool* result);

bool
GetOwnPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id,
                         MutableHandle<JS::PropertyDescriptor> desc);

bool
GetOwnPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id, MutableHandleValue vp);

/*
 * Like JS::FromPropertyDescriptor, but ignore desc.object() and always set vp
 * to an object on success.
 *
 * Use JS::FromPropertyDescriptor for getOwnPropertyDescriptor, since desc.object()
 * is used to indicate whether a result was found or not.  Use this instead for
 * defineProperty: it would be senseless to define a "missing" property.
 */
extern bool
FromPropertyDescriptorToObject(JSContext* cx, Handle<JS::PropertyDescriptor> desc,
                               MutableHandleValue vp);

extern bool
IsDelegate(JSContext* cx, HandleObject obj, const Value& v, bool* result);

// obj is a JSObject*, but we root it immediately up front. We do it
// that way because we need a Rooted temporary in this method anyway.
extern bool
IsDelegateOfObject(JSContext* cx, HandleObject protoObj, JSObject* obj, bool* result);

/* Wrap boolean, number or string as Boolean, Number or String object. */
extern JSObject*
PrimitiveToObject(JSContext* cx, const Value& v);

} /* namespace js */

namespace js {

/* For converting stack values to objects. */
MOZ_ALWAYS_INLINE JSObject*
ToObjectFromStack(JSContext* cx, HandleValue vp)
{
    if (vp.isObject())
        return &vp.toObject();
    return js::ToObjectSlow(cx, vp, true);
}

template<XDRMode mode>
bool
XDRObjectLiteral(XDRState<mode>* xdr, MutableHandleObject obj);

/*
 * Report a TypeError: "so-and-so is not an object".
 * Using NotNullObject is usually less code.
 */
extern void
ReportNotObject(JSContext* cx, const Value& v);

inline JSObject*
NonNullObject(JSContext* cx, const Value& v)
{
    if (v.isObject())
        return &v.toObject();
    ReportNotObject(cx, v);
    return nullptr;
}


extern bool
GetFirstArgumentAsObject(JSContext* cx, const CallArgs& args, const char* method,
                         MutableHandleObject objp);

/* Helpers for throwing. These always return false. */
extern bool
Throw(JSContext* cx, jsid id, unsigned errorNumber);

extern bool
Throw(JSContext* cx, JSObject* obj, unsigned errorNumber);

/*
 * ES6 rev 29 (6 Dec 2014) 7.3.13. Mark obj as non-extensible, and adjust each
 * of obj's own properties' attributes appropriately: each property becomes
 * non-configurable, and if level == Frozen, data properties become
 * non-writable as well.
 */
extern bool
SetIntegrityLevel(JSContext* cx, HandleObject obj, IntegrityLevel level);

inline bool
FreezeObject(JSContext* cx, HandleObject obj)
{
    return SetIntegrityLevel(cx, obj, IntegrityLevel::Frozen);
}

/*
 * ES6 rev 29 (6 Dec 2014) 7.3.14. Code shared by Object.isSealed and
 * Object.isFrozen.
 */
extern bool
TestIntegrityLevel(JSContext* cx, HandleObject obj, IntegrityLevel level, bool* resultp);

extern bool
SpeciesConstructor(JSContext* cx, HandleObject obj, HandleValue defaultCtor, MutableHandleValue pctor);

extern bool
SpeciesConstructor(JSContext* cx, HandleObject obj, JSProtoKey ctorKey, MutableHandleValue pctor);

extern bool
GetObjectFromIncumbentGlobal(JSContext* cx, MutableHandleObject obj);

}  /* namespace js */

#endif /* jsobj_h */