forked from nodejs/node
-
Notifications
You must be signed in to change notification settings - Fork 1
/
v8.h
10578 lines (9089 loc) · 339 KB
/
v8.h
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
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/** \mainpage V8 API Reference Guide
*
* V8 is Google's open source JavaScript engine.
*
* This set of documents provides reference material generated from the
* V8 header file, include/v8.h.
*
* For other documentation see http://code.google.com/apis/v8/
*/
#ifndef INCLUDE_V8_H_
#define INCLUDE_V8_H_
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <memory>
#include <utility>
#include <vector>
#include "v8-version.h" // NOLINT(build/include)
#include "v8config.h" // NOLINT(build/include)
// We reserve the V8_* prefix for macros defined in V8 public API and
// assume there are no name conflicts with the embedder's code.
#ifdef V8_OS_WIN
// Setup for Windows DLL export/import. When building the V8 DLL the
// BUILDING_V8_SHARED needs to be defined. When building a program which uses
// the V8 DLL USING_V8_SHARED needs to be defined. When either building the V8
// static library or building a program which uses the V8 static library neither
// BUILDING_V8_SHARED nor USING_V8_SHARED should be defined.
#ifdef BUILDING_V8_SHARED
# define V8_EXPORT __declspec(dllexport)
#elif USING_V8_SHARED
# define V8_EXPORT __declspec(dllimport)
#else
# define V8_EXPORT
#endif // BUILDING_V8_SHARED
#else // V8_OS_WIN
// Setup for Linux shared library export.
#if V8_HAS_ATTRIBUTE_VISIBILITY
# ifdef BUILDING_V8_SHARED
# define V8_EXPORT __attribute__ ((visibility("default")))
# else
# define V8_EXPORT
# endif
#else
# define V8_EXPORT
#endif
#endif // V8_OS_WIN
/**
* The v8 JavaScript engine.
*/
namespace v8 {
class AccessorSignature;
class Array;
class ArrayBuffer;
class BigInt;
class BigIntObject;
class Boolean;
class BooleanObject;
class Context;
class CpuProfiler;
class Data;
class Date;
class External;
class Function;
class FunctionTemplate;
class HeapProfiler;
class ImplementationUtilities;
class Int32;
class Integer;
class Isolate;
template <class T>
class Maybe;
class Name;
class Number;
class NumberObject;
class Object;
class ObjectOperationDescriptor;
class ObjectTemplate;
class Platform;
class Primitive;
class Promise;
class PropertyDescriptor;
class Proxy;
class RawOperationDescriptor;
class Script;
class SharedArrayBuffer;
class Signature;
class StartupData;
class StackFrame;
class StackTrace;
class String;
class StringObject;
class Symbol;
class SymbolObject;
class PrimitiveArray;
class Private;
class Uint32;
class Utils;
class Value;
class WasmCompiledModule;
template <class T> class Local;
template <class T>
class MaybeLocal;
template <class T> class Eternal;
template<class T> class NonCopyablePersistentTraits;
template<class T> class PersistentBase;
template <class T, class M = NonCopyablePersistentTraits<T> >
class Persistent;
template <class T>
class Global;
template<class K, class V, class T> class PersistentValueMap;
template <class K, class V, class T>
class PersistentValueMapBase;
template <class K, class V, class T>
class GlobalValueMap;
template<class V, class T> class PersistentValueVector;
template<class T, class P> class WeakCallbackObject;
class FunctionTemplate;
class ObjectTemplate;
template<typename T> class FunctionCallbackInfo;
template<typename T> class PropertyCallbackInfo;
class StackTrace;
class StackFrame;
class Isolate;
class CallHandlerHelper;
class EscapableHandleScope;
template<typename T> class ReturnValue;
namespace internal {
class Arguments;
class DeferredHandles;
class Heap;
class HeapObject;
class Isolate;
class Object;
struct ScriptStreamingData;
template<typename T> class CustomArguments;
class PropertyCallbackArguments;
class FunctionCallbackArguments;
class GlobalHandles;
namespace wasm {
class StreamingDecoder;
} // namespace wasm
} // namespace internal
namespace debug {
class ConsoleCallArguments;
} // namespace debug
// --- Handles ---
#define TYPE_CHECK(T, S) \
while (false) { \
*(static_cast<T* volatile*>(0)) = static_cast<S*>(0); \
}
/**
* An object reference managed by the v8 garbage collector.
*
* All objects returned from v8 have to be tracked by the garbage
* collector so that it knows that the objects are still alive. Also,
* because the garbage collector may move objects, it is unsafe to
* point directly to an object. Instead, all objects are stored in
* handles which are known by the garbage collector and updated
* whenever an object moves. Handles should always be passed by value
* (except in cases like out-parameters) and they should never be
* allocated on the heap.
*
* There are two types of handles: local and persistent handles.
*
* Local handles are light-weight and transient and typically used in
* local operations. They are managed by HandleScopes. That means that a
* HandleScope must exist on the stack when they are created and that they are
* only valid inside of the HandleScope active during their creation.
* For passing a local handle to an outer HandleScope, an EscapableHandleScope
* and its Escape() method must be used.
*
* Persistent handles can be used when storing objects across several
* independent operations and have to be explicitly deallocated when they're no
* longer used.
*
* It is safe to extract the object stored in the handle by
* dereferencing the handle (for instance, to extract the Object* from
* a Local<Object>); the value will still be governed by a handle
* behind the scenes and the same rules apply to these values as to
* their handles.
*/
template <class T>
class Local {
public:
V8_INLINE Local() : val_(0) {}
template <class S>
V8_INLINE Local(Local<S> that)
: val_(reinterpret_cast<T*>(*that)) {
/**
* This check fails when trying to convert between incompatible
* handles. For example, converting from a Local<String> to a
* Local<Number>.
*/
TYPE_CHECK(T, S);
}
/**
* Returns true if the handle is empty.
*/
V8_INLINE bool IsEmpty() const { return val_ == 0; }
/**
* Sets the handle to be empty. IsEmpty() will then return true.
*/
V8_INLINE void Clear() { val_ = 0; }
V8_INLINE T* operator->() const { return val_; }
V8_INLINE T* operator*() const { return val_; }
/**
* Checks whether two handles are the same.
* Returns true if both are empty, or if the objects
* to which they refer are identical.
* The handles' references are not checked.
*/
template <class S>
V8_INLINE bool operator==(const Local<S>& that) const {
internal::Object** a = reinterpret_cast<internal::Object**>(this->val_);
internal::Object** b = reinterpret_cast<internal::Object**>(that.val_);
if (a == 0) return b == 0;
if (b == 0) return false;
return *a == *b;
}
template <class S> V8_INLINE bool operator==(
const PersistentBase<S>& that) const {
internal::Object** a = reinterpret_cast<internal::Object**>(this->val_);
internal::Object** b = reinterpret_cast<internal::Object**>(that.val_);
if (a == 0) return b == 0;
if (b == 0) return false;
return *a == *b;
}
/**
* Checks whether two handles are different.
* Returns true if only one of the handles is empty, or if
* the objects to which they refer are different.
* The handles' references are not checked.
*/
template <class S>
V8_INLINE bool operator!=(const Local<S>& that) const {
return !operator==(that);
}
template <class S> V8_INLINE bool operator!=(
const Persistent<S>& that) const {
return !operator==(that);
}
/**
* Cast a handle to a subclass, e.g. Local<Value> to Local<Object>.
* This is only valid if the handle actually refers to a value of the
* target type.
*/
template <class S> V8_INLINE static Local<T> Cast(Local<S> that) {
#ifdef V8_ENABLE_CHECKS
// If we're going to perform the type check then we have to check
// that the handle isn't empty before doing the checked cast.
if (that.IsEmpty()) return Local<T>();
#endif
return Local<T>(T::Cast(*that));
}
/**
* Calling this is equivalent to Local<S>::Cast().
* In particular, this is only valid if the handle actually refers to a value
* of the target type.
*/
template <class S>
V8_INLINE Local<S> As() const {
return Local<S>::Cast(*this);
}
/**
* Create a local handle for the content of another handle.
* The referee is kept alive by the local handle even when
* the original handle is destroyed/disposed.
*/
V8_INLINE static Local<T> New(Isolate* isolate, Local<T> that);
V8_INLINE static Local<T> New(Isolate* isolate,
const PersistentBase<T>& that);
private:
friend class Utils;
template<class F> friend class Eternal;
template<class F> friend class PersistentBase;
template<class F, class M> friend class Persistent;
template<class F> friend class Local;
template <class F>
friend class MaybeLocal;
template<class F> friend class FunctionCallbackInfo;
template<class F> friend class PropertyCallbackInfo;
friend class String;
friend class Object;
friend class Context;
friend class Isolate;
friend class Private;
template<class F> friend class internal::CustomArguments;
friend Local<Primitive> Undefined(Isolate* isolate);
friend Local<Primitive> Null(Isolate* isolate);
friend Local<Boolean> True(Isolate* isolate);
friend Local<Boolean> False(Isolate* isolate);
friend class HandleScope;
friend class EscapableHandleScope;
template <class F1, class F2, class F3>
friend class PersistentValueMapBase;
template<class F1, class F2> friend class PersistentValueVector;
template <class F>
friend class ReturnValue;
explicit V8_INLINE Local(T* that) : val_(that) {}
V8_INLINE static Local<T> New(Isolate* isolate, T* that);
T* val_;
};
#if !defined(V8_IMMINENT_DEPRECATION_WARNINGS)
// Handle is an alias for Local for historical reasons.
template <class T>
using Handle = Local<T>;
#endif
/**
* A MaybeLocal<> is a wrapper around Local<> that enforces a check whether
* the Local<> is empty before it can be used.
*
* If an API method returns a MaybeLocal<>, the API method can potentially fail
* either because an exception is thrown, or because an exception is pending,
* e.g. because a previous API call threw an exception that hasn't been caught
* yet, or because a TerminateExecution exception was thrown. In that case, an
* empty MaybeLocal is returned.
*/
template <class T>
class MaybeLocal {
public:
V8_INLINE MaybeLocal() : val_(nullptr) {}
template <class S>
V8_INLINE MaybeLocal(Local<S> that)
: val_(reinterpret_cast<T*>(*that)) {
TYPE_CHECK(T, S);
}
V8_INLINE bool IsEmpty() const { return val_ == nullptr; }
/**
* Converts this MaybeLocal<> to a Local<>. If this MaybeLocal<> is empty,
* |false| is returned and |out| is left untouched.
*/
template <class S>
V8_WARN_UNUSED_RESULT V8_INLINE bool ToLocal(Local<S>* out) const {
out->val_ = IsEmpty() ? nullptr : this->val_;
return !IsEmpty();
}
/**
* Converts this MaybeLocal<> to a Local<>. If this MaybeLocal<> is empty,
* V8 will crash the process.
*/
V8_INLINE Local<T> ToLocalChecked();
/**
* Converts this MaybeLocal<> to a Local<>, using a default value if this
* MaybeLocal<> is empty.
*/
template <class S>
V8_INLINE Local<S> FromMaybe(Local<S> default_value) const {
return IsEmpty() ? default_value : Local<S>(val_);
}
private:
T* val_;
};
/**
* Eternal handles are set-once handles that live for the lifetime of the
* isolate.
*/
template <class T> class Eternal {
public:
V8_INLINE Eternal() : val_(nullptr) {}
template <class S>
V8_INLINE Eternal(Isolate* isolate, Local<S> handle) : val_(nullptr) {
Set(isolate, handle);
}
// Can only be safely called if already set.
V8_INLINE Local<T> Get(Isolate* isolate) const;
V8_INLINE bool IsEmpty() const { return val_ == nullptr; }
template<class S> V8_INLINE void Set(Isolate* isolate, Local<S> handle);
private:
T* val_;
};
static const int kInternalFieldsInWeakCallback = 2;
static const int kEmbedderFieldsInWeakCallback = 2;
template <typename T>
class WeakCallbackInfo {
public:
typedef void (*Callback)(const WeakCallbackInfo<T>& data);
WeakCallbackInfo(Isolate* isolate, T* parameter,
void* embedder_fields[kEmbedderFieldsInWeakCallback],
Callback* callback)
: isolate_(isolate), parameter_(parameter), callback_(callback) {
for (int i = 0; i < kEmbedderFieldsInWeakCallback; ++i) {
embedder_fields_[i] = embedder_fields[i];
}
}
V8_INLINE Isolate* GetIsolate() const { return isolate_; }
V8_INLINE T* GetParameter() const { return parameter_; }
V8_INLINE void* GetInternalField(int index) const;
// When first called, the embedder MUST Reset() the Global which triggered the
// callback. The Global itself is unusable for anything else. No v8 other api
// calls may be called in the first callback. Should additional work be
// required, the embedder must set a second pass callback, which will be
// called after all the initial callbacks are processed.
// Calling SetSecondPassCallback on the second pass will immediately crash.
void SetSecondPassCallback(Callback callback) const { *callback_ = callback; }
private:
Isolate* isolate_;
T* parameter_;
Callback* callback_;
void* embedder_fields_[kEmbedderFieldsInWeakCallback];
};
// kParameter will pass a void* parameter back to the callback, kInternalFields
// will pass the first two internal fields back to the callback, kFinalizer
// will pass a void* parameter back, but is invoked before the object is
// actually collected, so it can be resurrected. In the last case, it is not
// possible to request a second pass callback.
enum class WeakCallbackType { kParameter, kInternalFields, kFinalizer };
/**
* An object reference that is independent of any handle scope. Where
* a Local handle only lives as long as the HandleScope in which it was
* allocated, a PersistentBase handle remains valid until it is explicitly
* disposed using Reset().
*
* A persistent handle contains a reference to a storage cell within
* the V8 engine which holds an object value and which is updated by
* the garbage collector whenever the object is moved. A new storage
* cell can be created using the constructor or PersistentBase::Reset and
* existing handles can be disposed using PersistentBase::Reset.
*
*/
template <class T> class PersistentBase {
public:
/**
* If non-empty, destroy the underlying storage cell
* IsEmpty() will return true after this call.
*/
V8_INLINE void Reset();
/**
* If non-empty, destroy the underlying storage cell
* and create a new one with the contents of other if other is non empty
*/
template <class S>
V8_INLINE void Reset(Isolate* isolate, const Local<S>& other);
/**
* If non-empty, destroy the underlying storage cell
* and create a new one with the contents of other if other is non empty
*/
template <class S>
V8_INLINE void Reset(Isolate* isolate, const PersistentBase<S>& other);
V8_INLINE bool IsEmpty() const { return val_ == NULL; }
V8_INLINE void Empty() { val_ = 0; }
V8_INLINE Local<T> Get(Isolate* isolate) const {
return Local<T>::New(isolate, *this);
}
template <class S>
V8_INLINE bool operator==(const PersistentBase<S>& that) const {
internal::Object** a = reinterpret_cast<internal::Object**>(this->val_);
internal::Object** b = reinterpret_cast<internal::Object**>(that.val_);
if (a == NULL) return b == NULL;
if (b == NULL) return false;
return *a == *b;
}
template <class S>
V8_INLINE bool operator==(const Local<S>& that) const {
internal::Object** a = reinterpret_cast<internal::Object**>(this->val_);
internal::Object** b = reinterpret_cast<internal::Object**>(that.val_);
if (a == NULL) return b == NULL;
if (b == NULL) return false;
return *a == *b;
}
template <class S>
V8_INLINE bool operator!=(const PersistentBase<S>& that) const {
return !operator==(that);
}
template <class S>
V8_INLINE bool operator!=(const Local<S>& that) const {
return !operator==(that);
}
/**
* Install a finalization callback on this object.
* NOTE: There is no guarantee as to *when* or even *if* the callback is
* invoked. The invocation is performed solely on a best effort basis.
* As always, GC-based finalization should *not* be relied upon for any
* critical form of resource management!
*/
template <typename P>
V8_INLINE void SetWeak(P* parameter,
typename WeakCallbackInfo<P>::Callback callback,
WeakCallbackType type);
/**
* Turns this handle into a weak phantom handle without finalization callback.
* The handle will be reset automatically when the garbage collector detects
* that the object is no longer reachable.
* A related function Isolate::NumberOfPhantomHandleResetsSinceLastCall
* returns how many phantom handles were reset by the garbage collector.
*/
V8_INLINE void SetWeak();
template<typename P>
V8_INLINE P* ClearWeak();
// TODO(dcarney): remove this.
V8_INLINE void ClearWeak() { ClearWeak<void>(); }
/**
* Annotates the strong handle with the given label, which is then used by the
* heap snapshot generator as a name of the edge from the root to the handle.
* The function does not take ownership of the label and assumes that the
* label is valid as long as the handle is valid.
*/
V8_INLINE void AnnotateStrongRetainer(const char* label);
/**
* Allows the embedder to tell the v8 garbage collector that a certain object
* is alive. Only allowed when the embedder is asked to trace its heap by
* EmbedderHeapTracer.
*/
V8_INLINE void RegisterExternalReference(Isolate* isolate) const;
/**
* Marks the reference to this object independent. Garbage collector is free
* to ignore any object groups containing this object. Weak callback for an
* independent handle should not assume that it will be preceded by a global
* GC prologue callback or followed by a global GC epilogue callback.
*/
V8_DEPRECATE_SOON(
"Objects are always considered independent. "
"Use MarkActive to avoid collecting otherwise dead weak handles.",
V8_INLINE void MarkIndependent());
/**
* Marks the reference to this object as active. The scavenge garbage
* collection should not reclaim the objects marked as active, even if the
* object held by the handle is otherwise unreachable.
*
* This bit is cleared after the each garbage collection pass.
*/
V8_INLINE void MarkActive();
V8_DEPRECATE_SOON("See MarkIndependent.",
V8_INLINE bool IsIndependent() const);
/** Checks if the handle holds the only reference to an object. */
V8_INLINE bool IsNearDeath() const;
/** Returns true if the handle's reference is weak. */
V8_INLINE bool IsWeak() const;
/**
* Assigns a wrapper class ID to the handle. See RetainedObjectInfo interface
* description in v8-profiler.h for details.
*/
V8_INLINE void SetWrapperClassId(uint16_t class_id);
/**
* Returns the class ID previously assigned to this handle or 0 if no class ID
* was previously assigned.
*/
V8_INLINE uint16_t WrapperClassId() const;
PersistentBase(const PersistentBase& other) = delete; // NOLINT
void operator=(const PersistentBase&) = delete;
private:
friend class Isolate;
friend class Utils;
template<class F> friend class Local;
template<class F1, class F2> friend class Persistent;
template <class F>
friend class Global;
template<class F> friend class PersistentBase;
template<class F> friend class ReturnValue;
template <class F1, class F2, class F3>
friend class PersistentValueMapBase;
template<class F1, class F2> friend class PersistentValueVector;
friend class Object;
explicit V8_INLINE PersistentBase(T* val) : val_(val) {}
V8_INLINE static T* New(Isolate* isolate, T* that);
T* val_;
};
/**
* Default traits for Persistent. This class does not allow
* use of the copy constructor or assignment operator.
* At present kResetInDestructor is not set, but that will change in a future
* version.
*/
template<class T>
class NonCopyablePersistentTraits {
public:
typedef Persistent<T, NonCopyablePersistentTraits<T> > NonCopyablePersistent;
static const bool kResetInDestructor = false;
template<class S, class M>
V8_INLINE static void Copy(const Persistent<S, M>& source,
NonCopyablePersistent* dest) {
Uncompilable<Object>();
}
// TODO(dcarney): come up with a good compile error here.
template<class O> V8_INLINE static void Uncompilable() {
TYPE_CHECK(O, Primitive);
}
};
/**
* Helper class traits to allow copying and assignment of Persistent.
* This will clone the contents of storage cell, but not any of the flags, etc.
*/
template<class T>
struct CopyablePersistentTraits {
typedef Persistent<T, CopyablePersistentTraits<T> > CopyablePersistent;
static const bool kResetInDestructor = true;
template<class S, class M>
static V8_INLINE void Copy(const Persistent<S, M>& source,
CopyablePersistent* dest) {
// do nothing, just allow copy
}
};
/**
* A PersistentBase which allows copy and assignment.
*
* Copy, assignment and destructor behavior is controlled by the traits
* class M.
*
* Note: Persistent class hierarchy is subject to future changes.
*/
template <class T, class M> class Persistent : public PersistentBase<T> {
public:
/**
* A Persistent with no storage cell.
*/
V8_INLINE Persistent() : PersistentBase<T>(0) { }
/**
* Construct a Persistent from a Local.
* When the Local is non-empty, a new storage cell is created
* pointing to the same object, and no flags are set.
*/
template <class S>
V8_INLINE Persistent(Isolate* isolate, Local<S> that)
: PersistentBase<T>(PersistentBase<T>::New(isolate, *that)) {
TYPE_CHECK(T, S);
}
/**
* Construct a Persistent from a Persistent.
* When the Persistent is non-empty, a new storage cell is created
* pointing to the same object, and no flags are set.
*/
template <class S, class M2>
V8_INLINE Persistent(Isolate* isolate, const Persistent<S, M2>& that)
: PersistentBase<T>(PersistentBase<T>::New(isolate, *that)) {
TYPE_CHECK(T, S);
}
/**
* The copy constructors and assignment operator create a Persistent
* exactly as the Persistent constructor, but the Copy function from the
* traits class is called, allowing the setting of flags based on the
* copied Persistent.
*/
V8_INLINE Persistent(const Persistent& that) : PersistentBase<T>(0) {
Copy(that);
}
template <class S, class M2>
V8_INLINE Persistent(const Persistent<S, M2>& that) : PersistentBase<T>(0) {
Copy(that);
}
V8_INLINE Persistent& operator=(const Persistent& that) { // NOLINT
Copy(that);
return *this;
}
template <class S, class M2>
V8_INLINE Persistent& operator=(const Persistent<S, M2>& that) { // NOLINT
Copy(that);
return *this;
}
/**
* The destructor will dispose the Persistent based on the
* kResetInDestructor flags in the traits class. Since not calling dispose
* can result in a memory leak, it is recommended to always set this flag.
*/
V8_INLINE ~Persistent() {
if (M::kResetInDestructor) this->Reset();
}
// TODO(dcarney): this is pretty useless, fix or remove
template <class S>
V8_INLINE static Persistent<T>& Cast(const Persistent<S>& that) { // NOLINT
#ifdef V8_ENABLE_CHECKS
// If we're going to perform the type check then we have to check
// that the handle isn't empty before doing the checked cast.
if (!that.IsEmpty()) T::Cast(*that);
#endif
return reinterpret_cast<Persistent<T>&>(const_cast<Persistent<S>&>(that));
}
// TODO(dcarney): this is pretty useless, fix or remove
template <class S>
V8_INLINE Persistent<S>& As() const { // NOLINT
return Persistent<S>::Cast(*this);
}
private:
friend class Isolate;
friend class Utils;
template<class F> friend class Local;
template<class F1, class F2> friend class Persistent;
template<class F> friend class ReturnValue;
explicit V8_INLINE Persistent(T* that) : PersistentBase<T>(that) {}
V8_INLINE T* operator*() const { return this->val_; }
template<class S, class M2>
V8_INLINE void Copy(const Persistent<S, M2>& that);
};
/**
* A PersistentBase which has move semantics.
*
* Note: Persistent class hierarchy is subject to future changes.
*/
template <class T>
class Global : public PersistentBase<T> {
public:
/**
* A Global with no storage cell.
*/
V8_INLINE Global() : PersistentBase<T>(nullptr) {}
/**
* Construct a Global from a Local.
* When the Local is non-empty, a new storage cell is created
* pointing to the same object, and no flags are set.
*/
template <class S>
V8_INLINE Global(Isolate* isolate, Local<S> that)
: PersistentBase<T>(PersistentBase<T>::New(isolate, *that)) {
TYPE_CHECK(T, S);
}
/**
* Construct a Global from a PersistentBase.
* When the Persistent is non-empty, a new storage cell is created
* pointing to the same object, and no flags are set.
*/
template <class S>
V8_INLINE Global(Isolate* isolate, const PersistentBase<S>& that)
: PersistentBase<T>(PersistentBase<T>::New(isolate, that.val_)) {
TYPE_CHECK(T, S);
}
/**
* Move constructor.
*/
V8_INLINE Global(Global&& other) : PersistentBase<T>(other.val_) { // NOLINT
other.val_ = nullptr;
}
V8_INLINE ~Global() { this->Reset(); }
/**
* Move via assignment.
*/
template <class S>
V8_INLINE Global& operator=(Global<S>&& rhs) { // NOLINT
TYPE_CHECK(T, S);
if (this != &rhs) {
this->Reset();
this->val_ = rhs.val_;
rhs.val_ = nullptr;
}
return *this;
}
/**
* Pass allows returning uniques from functions, etc.
*/
Global Pass() { return static_cast<Global&&>(*this); } // NOLINT
/*
* For compatibility with Chromium's base::Bind (base::Passed).
*/
typedef void MoveOnlyTypeForCPP03;
Global(const Global&) = delete;
void operator=(const Global&) = delete;
private:
template <class F>
friend class ReturnValue;
V8_INLINE T* operator*() const { return this->val_; }
};
// UniquePersistent is an alias for Global for historical reason.
template <class T>
using UniquePersistent = Global<T>;
/**
* A stack-allocated class that governs a number of local handles.
* After a handle scope has been created, all local handles will be
* allocated within that handle scope until either the handle scope is
* deleted or another handle scope is created. If there is already a
* handle scope and a new one is created, all allocations will take
* place in the new handle scope until it is deleted. After that,
* new handles will again be allocated in the original handle scope.
*
* After the handle scope of a local handle has been deleted the
* garbage collector will no longer track the object stored in the
* handle and may deallocate it. The behavior of accessing a handle
* for which the handle scope has been deleted is undefined.
*/
class V8_EXPORT HandleScope {
public:
explicit HandleScope(Isolate* isolate);
~HandleScope();
/**
* Counts the number of allocated handles.
*/
static int NumberOfHandles(Isolate* isolate);
V8_INLINE Isolate* GetIsolate() const {
return reinterpret_cast<Isolate*>(isolate_);
}
HandleScope(const HandleScope&) = delete;
void operator=(const HandleScope&) = delete;
protected:
V8_INLINE HandleScope() {}
void Initialize(Isolate* isolate);
static internal::Object** CreateHandle(internal::Isolate* isolate,
internal::Object* value);
private:
// Declaring operator new and delete as deleted is not spec compliant.
// Therefore declare them private instead to disable dynamic alloc
void* operator new(size_t size);
void* operator new[](size_t size);
void operator delete(void*, size_t);
void operator delete[](void*, size_t);
// Uses heap_object to obtain the current Isolate.
static internal::Object** CreateHandle(internal::HeapObject* heap_object,
internal::Object* value);
internal::Isolate* isolate_;
internal::Object** prev_next_;
internal::Object** prev_limit_;
// Local::New uses CreateHandle with an Isolate* parameter.
template<class F> friend class Local;
// Object::GetInternalField and Context::GetEmbedderData use CreateHandle with
// a HeapObject* in their shortcuts.
friend class Object;
friend class Context;
};
/**
* A HandleScope which first allocates a handle in the current scope
* which will be later filled with the escape value.
*/
class V8_EXPORT EscapableHandleScope : public HandleScope {
public:
explicit EscapableHandleScope(Isolate* isolate);
V8_INLINE ~EscapableHandleScope() {}
/**
* Pushes the value into the previous scope and returns a handle to it.
* Cannot be called twice.
*/
template <class T>
V8_INLINE Local<T> Escape(Local<T> value) {
internal::Object** slot =
Escape(reinterpret_cast<internal::Object**>(*value));
return Local<T>(reinterpret_cast<T*>(slot));
}
EscapableHandleScope(const EscapableHandleScope&) = delete;
void operator=(const EscapableHandleScope&) = delete;
private:
// Declaring operator new and delete as deleted is not spec compliant.
// Therefore declare them private instead to disable dynamic alloc
void* operator new(size_t size);
void* operator new[](size_t size);
void operator delete(void*, size_t);
void operator delete[](void*, size_t);
internal::Object** Escape(internal::Object** escape_value);
internal::Object** escape_slot_;
};
/**
* A SealHandleScope acts like a handle scope in which no handle allocations
* are allowed. It can be useful for debugging handle leaks.
* Handles can be allocated within inner normal HandleScopes.
*/
class V8_EXPORT SealHandleScope {
public:
explicit SealHandleScope(Isolate* isolate);
~SealHandleScope();
SealHandleScope(const SealHandleScope&) = delete;
void operator=(const SealHandleScope&) = delete;
private:
// Declaring operator new and delete as deleted is not spec compliant.
// Therefore declare them private instead to disable dynamic alloc
void* operator new(size_t size);
void* operator new[](size_t size);
void operator delete(void*, size_t);
void operator delete[](void*, size_t);
internal::Isolate* const isolate_;
internal::Object** prev_limit_;
int prev_sealed_level_;
};
// --- Special objects ---
/**
* The superclass of values and API object templates.
*/
class V8_EXPORT Data {
private:
Data();
};
/**
* A container type that holds relevant metadata for module loading.
*
* This is passed back to the embedder as part of
* HostImportModuleDynamicallyCallback for module loading.
*/
class V8_EXPORT ScriptOrModule {
public:
/**
* The name that was passed by the embedder as ResourceName to the
* ScriptOrigin. This can be either a v8::String or v8::Undefined.
*/