1 // Copyright 2012 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #ifndef V8_API_H_
6 #define V8_API_H_
7
8 #include "src/v8.h"
9
10 #include "include/v8-testing.h"
11 #include "src/contexts.h"
12 #include "src/factory.h"
13 #include "src/isolate.h"
14 #include "src/list-inl.h"
15
16 namespace v8 {
17
18 // Constants used in the implementation of the API. The most natural thing
19 // would usually be to place these with the classes that use them, but
20 // we want to keep them out of v8.h because it is an externally
21 // visible file.
22 class Consts {
23 public:
24 enum TemplateType {
25 FUNCTION_TEMPLATE = 0,
26 OBJECT_TEMPLATE = 1
27 };
28 };
29
30
31 // Utilities for working with neander-objects, primitive
32 // env-independent JSObjects used by the api.
33 class NeanderObject {
34 public:
35 explicit NeanderObject(v8::internal::Isolate* isolate, int size);
36 explicit inline NeanderObject(v8::internal::Handle<v8::internal::Object> obj);
37 explicit inline NeanderObject(v8::internal::Object* obj);
38 inline v8::internal::Object* get(int index);
39 inline void set(int index, v8::internal::Object* value);
value()40 inline v8::internal::Handle<v8::internal::JSObject> value() { return value_; }
41 int size();
42 private:
43 v8::internal::Handle<v8::internal::JSObject> value_;
44 };
45
46
47 // Utilities for working with neander-arrays, a simple extensible
48 // array abstraction built on neander-objects.
49 class NeanderArray {
50 public:
51 explicit NeanderArray(v8::internal::Isolate* isolate);
52 explicit inline NeanderArray(v8::internal::Handle<v8::internal::Object> obj);
value()53 inline v8::internal::Handle<v8::internal::JSObject> value() {
54 return obj_.value();
55 }
56
57 void add(v8::internal::Handle<v8::internal::Object> value);
58
59 int length();
60
61 v8::internal::Object* get(int index);
62 // Change the value at an index to undefined value. If the index is
63 // out of bounds, the request is ignored. Returns the old value.
64 void set(int index, v8::internal::Object* value);
65 private:
66 NeanderObject obj_;
67 };
68
69
NeanderObject(v8::internal::Handle<v8::internal::Object> obj)70 NeanderObject::NeanderObject(v8::internal::Handle<v8::internal::Object> obj)
71 : value_(v8::internal::Handle<v8::internal::JSObject>::cast(obj)) { }
72
73
NeanderObject(v8::internal::Object * obj)74 NeanderObject::NeanderObject(v8::internal::Object* obj)
75 : value_(v8::internal::Handle<v8::internal::JSObject>(
76 v8::internal::JSObject::cast(obj))) { }
77
78
NeanderArray(v8::internal::Handle<v8::internal::Object> obj)79 NeanderArray::NeanderArray(v8::internal::Handle<v8::internal::Object> obj)
80 : obj_(obj) { }
81
82
get(int offset)83 v8::internal::Object* NeanderObject::get(int offset) {
84 DCHECK(value()->HasFastObjectElements());
85 return v8::internal::FixedArray::cast(value()->elements())->get(offset);
86 }
87
88
set(int offset,v8::internal::Object * value)89 void NeanderObject::set(int offset, v8::internal::Object* value) {
90 DCHECK(value_->HasFastObjectElements());
91 v8::internal::FixedArray::cast(value_->elements())->set(offset, value);
92 }
93
94
ToCData(v8::internal::Object * obj)95 template <typename T> inline T ToCData(v8::internal::Object* obj) {
96 STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
97 return reinterpret_cast<T>(
98 reinterpret_cast<intptr_t>(
99 v8::internal::Foreign::cast(obj)->foreign_address()));
100 }
101
102
103 template <typename T>
FromCData(v8::internal::Isolate * isolate,T obj)104 inline v8::internal::Handle<v8::internal::Object> FromCData(
105 v8::internal::Isolate* isolate, T obj) {
106 STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
107 return isolate->factory()->NewForeign(
108 reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
109 }
110
111
112 class ApiFunction {
113 public:
ApiFunction(v8::internal::Address addr)114 explicit ApiFunction(v8::internal::Address addr) : addr_(addr) { }
address()115 v8::internal::Address address() { return addr_; }
116 private:
117 v8::internal::Address addr_;
118 };
119
120
121
122 class RegisteredExtension {
123 public:
124 explicit RegisteredExtension(Extension* extension);
125 static void Register(RegisteredExtension* that);
126 static void UnregisterAll();
extension()127 Extension* extension() { return extension_; }
next()128 RegisteredExtension* next() { return next_; }
first_extension()129 static RegisteredExtension* first_extension() { return first_extension_; }
130 private:
131 Extension* extension_;
132 RegisteredExtension* next_;
133 static RegisteredExtension* first_extension_;
134 };
135
136
137 #define OPEN_HANDLE_LIST(V) \
138 V(Template, TemplateInfo) \
139 V(FunctionTemplate, FunctionTemplateInfo) \
140 V(ObjectTemplate, ObjectTemplateInfo) \
141 V(Signature, SignatureInfo) \
142 V(AccessorSignature, FunctionTemplateInfo) \
143 V(TypeSwitch, TypeSwitchInfo) \
144 V(Data, Object) \
145 V(RegExp, JSRegExp) \
146 V(Object, JSObject) \
147 V(Array, JSArray) \
148 V(ArrayBuffer, JSArrayBuffer) \
149 V(ArrayBufferView, JSArrayBufferView) \
150 V(TypedArray, JSTypedArray) \
151 V(Uint8Array, JSTypedArray) \
152 V(Uint8ClampedArray, JSTypedArray) \
153 V(Int8Array, JSTypedArray) \
154 V(Uint16Array, JSTypedArray) \
155 V(Int16Array, JSTypedArray) \
156 V(Uint32Array, JSTypedArray) \
157 V(Int32Array, JSTypedArray) \
158 V(Float32Array, JSTypedArray) \
159 V(Float64Array, JSTypedArray) \
160 V(DataView, JSDataView) \
161 V(Name, Name) \
162 V(String, String) \
163 V(Symbol, Symbol) \
164 V(Script, JSFunction) \
165 V(UnboundScript, SharedFunctionInfo) \
166 V(Function, JSFunction) \
167 V(Message, JSMessageObject) \
168 V(Context, Context) \
169 V(External, Object) \
170 V(StackTrace, JSArray) \
171 V(StackFrame, JSObject) \
172 V(DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
173
174
175 class Utils {
176 public:
ApiCheck(bool condition,const char * location,const char * message)177 static inline bool ApiCheck(bool condition,
178 const char* location,
179 const char* message) {
180 if (!condition) Utils::ReportApiFailure(location, message);
181 return condition;
182 }
183
184 static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
185 static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
186
187 static inline Local<Context> ToLocal(
188 v8::internal::Handle<v8::internal::Context> obj);
189 static inline Local<Value> ToLocal(
190 v8::internal::Handle<v8::internal::Object> obj);
191 static inline Local<Function> ToLocal(
192 v8::internal::Handle<v8::internal::JSFunction> obj);
193 static inline Local<Name> ToLocal(
194 v8::internal::Handle<v8::internal::Name> obj);
195 static inline Local<String> ToLocal(
196 v8::internal::Handle<v8::internal::String> obj);
197 static inline Local<Symbol> ToLocal(
198 v8::internal::Handle<v8::internal::Symbol> obj);
199 static inline Local<RegExp> ToLocal(
200 v8::internal::Handle<v8::internal::JSRegExp> obj);
201 static inline Local<Object> ToLocal(
202 v8::internal::Handle<v8::internal::JSObject> obj);
203 static inline Local<Array> ToLocal(
204 v8::internal::Handle<v8::internal::JSArray> obj);
205 static inline Local<ArrayBuffer> ToLocal(
206 v8::internal::Handle<v8::internal::JSArrayBuffer> obj);
207 static inline Local<ArrayBufferView> ToLocal(
208 v8::internal::Handle<v8::internal::JSArrayBufferView> obj);
209 static inline Local<DataView> ToLocal(
210 v8::internal::Handle<v8::internal::JSDataView> obj);
211
212 static inline Local<TypedArray> ToLocal(
213 v8::internal::Handle<v8::internal::JSTypedArray> obj);
214 static inline Local<Uint8Array> ToLocalUint8Array(
215 v8::internal::Handle<v8::internal::JSTypedArray> obj);
216 static inline Local<Uint8ClampedArray> ToLocalUint8ClampedArray(
217 v8::internal::Handle<v8::internal::JSTypedArray> obj);
218 static inline Local<Int8Array> ToLocalInt8Array(
219 v8::internal::Handle<v8::internal::JSTypedArray> obj);
220 static inline Local<Uint16Array> ToLocalUint16Array(
221 v8::internal::Handle<v8::internal::JSTypedArray> obj);
222 static inline Local<Int16Array> ToLocalInt16Array(
223 v8::internal::Handle<v8::internal::JSTypedArray> obj);
224 static inline Local<Uint32Array> ToLocalUint32Array(
225 v8::internal::Handle<v8::internal::JSTypedArray> obj);
226 static inline Local<Int32Array> ToLocalInt32Array(
227 v8::internal::Handle<v8::internal::JSTypedArray> obj);
228 static inline Local<Float32Array> ToLocalFloat32Array(
229 v8::internal::Handle<v8::internal::JSTypedArray> obj);
230 static inline Local<Float64Array> ToLocalFloat64Array(
231 v8::internal::Handle<v8::internal::JSTypedArray> obj);
232
233 static inline Local<Message> MessageToLocal(
234 v8::internal::Handle<v8::internal::Object> obj);
235 static inline Local<StackTrace> StackTraceToLocal(
236 v8::internal::Handle<v8::internal::JSArray> obj);
237 static inline Local<StackFrame> StackFrameToLocal(
238 v8::internal::Handle<v8::internal::JSObject> obj);
239 static inline Local<Number> NumberToLocal(
240 v8::internal::Handle<v8::internal::Object> obj);
241 static inline Local<Integer> IntegerToLocal(
242 v8::internal::Handle<v8::internal::Object> obj);
243 static inline Local<Uint32> Uint32ToLocal(
244 v8::internal::Handle<v8::internal::Object> obj);
245 static inline Local<FunctionTemplate> ToLocal(
246 v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
247 static inline Local<ObjectTemplate> ToLocal(
248 v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
249 static inline Local<Signature> ToLocal(
250 v8::internal::Handle<v8::internal::SignatureInfo> obj);
251 static inline Local<AccessorSignature> AccessorSignatureToLocal(
252 v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
253 static inline Local<TypeSwitch> ToLocal(
254 v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
255 static inline Local<External> ExternalToLocal(
256 v8::internal::Handle<v8::internal::JSObject> obj);
257 static inline Local<DeclaredAccessorDescriptor> ToLocal(
258 v8::internal::Handle<v8::internal::DeclaredAccessorDescriptor> obj);
259
260 #define DECLARE_OPEN_HANDLE(From, To) \
261 static inline v8::internal::Handle<v8::internal::To> \
262 OpenHandle(const From* that, bool allow_empty_handle = false);
263
OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)264 OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
265
266 #undef DECLARE_OPEN_HANDLE
267
268 template<class From, class To>
269 static inline Local<To> Convert(v8::internal::Handle<From> obj) {
270 DCHECK(obj.is_null() || !obj->IsTheHole());
271 return Local<To>(reinterpret_cast<To*>(obj.location()));
272 }
273
274 template <class T>
OpenPersistent(const v8::Persistent<T> & persistent)275 static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
276 const v8::Persistent<T>& persistent) {
277 return v8::internal::Handle<v8::internal::Object>(
278 reinterpret_cast<v8::internal::Object**>(persistent.val_));
279 }
280
281 template <class T>
OpenPersistent(v8::Persistent<T> * persistent)282 static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
283 v8::Persistent<T>* persistent) {
284 return OpenPersistent(*persistent);
285 }
286
287 template <class From, class To>
OpenHandle(v8::Local<From> handle)288 static inline v8::internal::Handle<To> OpenHandle(v8::Local<From> handle) {
289 return OpenHandle(*handle);
290 }
291
292 private:
293 static void ReportApiFailure(const char* location, const char* message);
294 };
295
296
297 template <class T>
EscapeFrom(v8::EscapableHandleScope * scope)298 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
299 v8::EscapableHandleScope* scope) {
300 v8::internal::Handle<T> handle;
301 if (!is_null()) {
302 handle = *this;
303 }
304 return Utils::OpenHandle(*scope->Escape(Utils::ToLocal(handle)), true);
305 }
306
307
308 template <class T>
ToApi(v8::internal::Handle<v8::internal::Object> obj)309 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
310 return reinterpret_cast<T*>(obj.location());
311 }
312
313 template <class T>
ToApiHandle(v8::internal::Handle<v8::internal::Object> obj)314 inline v8::Local<T> ToApiHandle(
315 v8::internal::Handle<v8::internal::Object> obj) {
316 return Utils::Convert<v8::internal::Object, T>(obj);
317 }
318
319
320 // Implementations of ToLocal
321
322 #define MAKE_TO_LOCAL(Name, From, To) \
323 Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
324 return Convert<v8::internal::From, v8::To>(obj); \
325 }
326
327
328 #define MAKE_TO_LOCAL_TYPED_ARRAY(Type, typeName, TYPE, ctype, size) \
329 Local<v8::Type##Array> Utils::ToLocal##Type##Array( \
330 v8::internal::Handle<v8::internal::JSTypedArray> obj) { \
331 DCHECK(obj->type() == kExternal##Type##Array); \
332 return Convert<v8::internal::JSTypedArray, v8::Type##Array>(obj); \
333 }
334
335
MAKE_TO_LOCAL(ToLocal,Context,Context)336 MAKE_TO_LOCAL(ToLocal, Context, Context)
337 MAKE_TO_LOCAL(ToLocal, Object, Value)
338 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
339 MAKE_TO_LOCAL(ToLocal, Name, Name)
340 MAKE_TO_LOCAL(ToLocal, String, String)
341 MAKE_TO_LOCAL(ToLocal, Symbol, Symbol)
342 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
343 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
344 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
345 MAKE_TO_LOCAL(ToLocal, JSArrayBuffer, ArrayBuffer)
346 MAKE_TO_LOCAL(ToLocal, JSArrayBufferView, ArrayBufferView)
347 MAKE_TO_LOCAL(ToLocal, JSDataView, DataView)
348 MAKE_TO_LOCAL(ToLocal, JSTypedArray, TypedArray)
349
350 TYPED_ARRAYS(MAKE_TO_LOCAL_TYPED_ARRAY)
351
352 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
353 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
354 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
355 MAKE_TO_LOCAL(AccessorSignatureToLocal, FunctionTemplateInfo, AccessorSignature)
356 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
357 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
358 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
359 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
360 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
361 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
362 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
363 MAKE_TO_LOCAL(ExternalToLocal, JSObject, External)
364 MAKE_TO_LOCAL(ToLocal, DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
365
366 #undef MAKE_TO_LOCAL_TYPED_ARRAY
367 #undef MAKE_TO_LOCAL
368
369
370 // Implementations of OpenHandle
371
372 #define MAKE_OPEN_HANDLE(From, To) \
373 v8::internal::Handle<v8::internal::To> Utils::OpenHandle( \
374 const v8::From* that, bool allow_empty_handle) { \
375 EXTRA_CHECK(allow_empty_handle || that != NULL); \
376 EXTRA_CHECK(that == NULL || \
377 (*reinterpret_cast<v8::internal::Object* const*>(that))->Is##To()); \
378 return v8::internal::Handle<v8::internal::To>( \
379 reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
380 }
381
382 OPEN_HANDLE_LIST(MAKE_OPEN_HANDLE)
383
384 #undef MAKE_OPEN_HANDLE
385 #undef OPEN_HANDLE_LIST
386
387
388 namespace internal {
389
390 // Tracks string usage to help make better decisions when
391 // externalizing strings.
392 //
393 // Implementation note: internally this class only tracks fresh
394 // strings and keeps a single use counter for them.
395 class StringTracker {
396 public:
397 // Records that the given string's characters were copied to some
398 // external buffer. If this happens often we should honor
399 // externalization requests for the string.
400 void RecordWrite(Handle<String> string) {
401 Address address = reinterpret_cast<Address>(*string);
402 Address top = isolate_->heap()->NewSpaceTop();
403 if (IsFreshString(address, top)) {
404 IncrementUseCount(top);
405 }
406 }
407
408 // Estimates freshness and use frequency of the given string based
409 // on how close it is to the new space top and the recorded usage
410 // history.
411 inline bool IsFreshUnusedString(Handle<String> string) {
412 Address address = reinterpret_cast<Address>(*string);
413 Address top = isolate_->heap()->NewSpaceTop();
414 return IsFreshString(address, top) && IsUseCountLow(top);
415 }
416
417 private:
418 StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
419
420 static inline bool IsFreshString(Address string, Address top) {
421 return top - kFreshnessLimit <= string && string <= top;
422 }
423
424 inline bool IsUseCountLow(Address top) {
425 if (last_top_ != top) return true;
426 return use_count_ < kUseLimit;
427 }
428
429 inline void IncrementUseCount(Address top) {
430 if (last_top_ != top) {
431 use_count_ = 0;
432 last_top_ = top;
433 }
434 ++use_count_;
435 }
436
437 // Single use counter shared by all fresh strings.
438 int use_count_;
439
440 // Last new space top when the use count above was valid.
441 Address last_top_;
442
443 Isolate* isolate_;
444
445 // How close to the new space top a fresh string has to be.
446 static const int kFreshnessLimit = 1024;
447
448 // The number of uses required to consider a string useful.
449 static const int kUseLimit = 32;
450
451 friend class Isolate;
452
453 DISALLOW_COPY_AND_ASSIGN(StringTracker);
454 };
455
456
457 class DeferredHandles {
458 public:
459 ~DeferredHandles();
460
461 private:
462 DeferredHandles(Object** first_block_limit, Isolate* isolate)
463 : next_(NULL),
464 previous_(NULL),
465 first_block_limit_(first_block_limit),
466 isolate_(isolate) {
467 isolate->LinkDeferredHandles(this);
468 }
469
470 void Iterate(ObjectVisitor* v);
471
472 List<Object**> blocks_;
473 DeferredHandles* next_;
474 DeferredHandles* previous_;
475 Object** first_block_limit_;
476 Isolate* isolate_;
477
478 friend class HandleScopeImplementer;
479 friend class Isolate;
480 };
481
482
483 // This class is here in order to be able to declare it a friend of
484 // HandleScope. Moving these methods to be members of HandleScope would be
485 // neat in some ways, but it would expose internal implementation details in
486 // our public header file, which is undesirable.
487 //
488 // An isolate has a single instance of this class to hold the current thread's
489 // data. In multithreaded V8 programs this data is copied in and out of storage
490 // so that the currently executing thread always has its own copy of this
491 // data.
492 class HandleScopeImplementer {
493 public:
494 explicit HandleScopeImplementer(Isolate* isolate)
495 : isolate_(isolate),
496 blocks_(0),
497 entered_contexts_(0),
498 saved_contexts_(0),
499 spare_(NULL),
500 call_depth_(0),
501 last_handle_before_deferred_block_(NULL) { }
502
503 ~HandleScopeImplementer() {
504 DeleteArray(spare_);
505 }
506
507 // Threading support for handle data.
508 static int ArchiveSpacePerThread();
509 char* RestoreThread(char* from);
510 char* ArchiveThread(char* to);
511 void FreeThreadResources();
512
513 // Garbage collection support.
514 void Iterate(v8::internal::ObjectVisitor* v);
515 static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
516
517
518 inline internal::Object** GetSpareOrNewBlock();
519 inline void DeleteExtensions(internal::Object** prev_limit);
520
521 inline void IncrementCallDepth() {call_depth_++;}
522 inline void DecrementCallDepth() {call_depth_--;}
523 inline bool CallDepthIsZero() { return call_depth_ == 0; }
524
525 inline void EnterContext(Handle<Context> context);
526 inline void LeaveContext();
527 inline bool LastEnteredContextWas(Handle<Context> context);
528
529 // Returns the last entered context or an empty handle if no
530 // contexts have been entered.
531 inline Handle<Context> LastEnteredContext();
532
533 inline void SaveContext(Context* context);
534 inline Context* RestoreContext();
535 inline bool HasSavedContexts();
536
537 inline List<internal::Object**>* blocks() { return &blocks_; }
538 Isolate* isolate() const { return isolate_; }
539
540 void ReturnBlock(Object** block) {
541 DCHECK(block != NULL);
542 if (spare_ != NULL) DeleteArray(spare_);
543 spare_ = block;
544 }
545
546 private:
547 void ResetAfterArchive() {
548 blocks_.Initialize(0);
549 entered_contexts_.Initialize(0);
550 saved_contexts_.Initialize(0);
551 spare_ = NULL;
552 last_handle_before_deferred_block_ = NULL;
553 call_depth_ = 0;
554 }
555
556 void Free() {
557 DCHECK(blocks_.length() == 0);
558 DCHECK(entered_contexts_.length() == 0);
559 DCHECK(saved_contexts_.length() == 0);
560 blocks_.Free();
561 entered_contexts_.Free();
562 saved_contexts_.Free();
563 if (spare_ != NULL) {
564 DeleteArray(spare_);
565 spare_ = NULL;
566 }
567 DCHECK(call_depth_ == 0);
568 }
569
570 void BeginDeferredScope();
571 DeferredHandles* Detach(Object** prev_limit);
572
573 Isolate* isolate_;
574 List<internal::Object**> blocks_;
575 // Used as a stack to keep track of entered contexts.
576 List<Context*> entered_contexts_;
577 // Used as a stack to keep track of saved contexts.
578 List<Context*> saved_contexts_;
579 Object** spare_;
580 int call_depth_;
581 Object** last_handle_before_deferred_block_;
582 // This is only used for threading support.
583 HandleScopeData handle_scope_data_;
584
585 void IterateThis(ObjectVisitor* v);
586 char* RestoreThreadHelper(char* from);
587 char* ArchiveThreadHelper(char* to);
588
589 friend class DeferredHandles;
590 friend class DeferredHandleScope;
591
592 DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
593 };
594
595
596 const int kHandleBlockSize = v8::internal::KB - 2; // fit in one page
597
598
599 void HandleScopeImplementer::SaveContext(Context* context) {
600 saved_contexts_.Add(context);
601 }
602
603
604 Context* HandleScopeImplementer::RestoreContext() {
605 return saved_contexts_.RemoveLast();
606 }
607
608
609 bool HandleScopeImplementer::HasSavedContexts() {
610 return !saved_contexts_.is_empty();
611 }
612
613
614 void HandleScopeImplementer::EnterContext(Handle<Context> context) {
615 entered_contexts_.Add(*context);
616 }
617
618
619 void HandleScopeImplementer::LeaveContext() {
620 entered_contexts_.RemoveLast();
621 }
622
623
624 bool HandleScopeImplementer::LastEnteredContextWas(Handle<Context> context) {
625 return !entered_contexts_.is_empty() && entered_contexts_.last() == *context;
626 }
627
628
629 Handle<Context> HandleScopeImplementer::LastEnteredContext() {
630 if (entered_contexts_.is_empty()) return Handle<Context>::null();
631 return Handle<Context>(entered_contexts_.last());
632 }
633
634
635 // If there's a spare block, use it for growing the current scope.
636 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
637 internal::Object** block = (spare_ != NULL) ?
638 spare_ :
639 NewArray<internal::Object*>(kHandleBlockSize);
640 spare_ = NULL;
641 return block;
642 }
643
644
645 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
646 while (!blocks_.is_empty()) {
647 internal::Object** block_start = blocks_.last();
648 internal::Object** block_limit = block_start + kHandleBlockSize;
649 #ifdef DEBUG
650 // SealHandleScope may make the prev_limit to point inside the block.
651 if (block_start <= prev_limit && prev_limit <= block_limit) {
652 #ifdef ENABLE_HANDLE_ZAPPING
653 internal::HandleScope::ZapRange(prev_limit, block_limit);
654 #endif
655 break;
656 }
657 #else
658 if (prev_limit == block_limit) break;
659 #endif
660
661 blocks_.RemoveLast();
662 #ifdef ENABLE_HANDLE_ZAPPING
663 internal::HandleScope::ZapRange(block_start, block_limit);
664 #endif
665 if (spare_ != NULL) {
666 DeleteArray(spare_);
667 }
668 spare_ = block_start;
669 }
670 DCHECK((blocks_.is_empty() && prev_limit == NULL) ||
671 (!blocks_.is_empty() && prev_limit != NULL));
672 }
673
674
675 // Interceptor functions called from generated inline caches to notify
676 // CPU profiler that external callbacks are invoked.
677 void InvokeAccessorGetterCallback(
678 v8::Local<v8::Name> property,
679 const v8::PropertyCallbackInfo<v8::Value>& info,
680 v8::AccessorNameGetterCallback getter);
681
682 void InvokeFunctionCallback(const v8::FunctionCallbackInfo<v8::Value>& info,
683 v8::FunctionCallback callback);
684
685 class Testing {
686 public:
687 static v8::Testing::StressType stress_type() { return stress_type_; }
688 static void set_stress_type(v8::Testing::StressType stress_type) {
689 stress_type_ = stress_type;
690 }
691
692 private:
693 static v8::Testing::StressType stress_type_;
694 };
695
696 } } // namespace v8::internal
697
698 #endif // V8_API_H_
699