src/api.h

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