src/v8/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 "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);
  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);
  53   inline v8::internal::Handle<v8::internal::JSObject> value() {
  54     return obj_.value();
  55   }
  56
  57   void add(internal::Isolate* isolate,
  58            v8::internal::Handle<v8::internal::Object> value);
  59
  60   int length();
  61
  62   v8::internal::Object* get(int index);
  63   // Change the value at an index to undefined value. If the index is
  64   // out of bounds, the request is ignored. Returns the old value.
  65   void set(int index, v8::internal::Object* value);
  66  private:
  67   NeanderObject obj_;
  68 };
  69
  70
  71 NeanderObject::NeanderObject(v8::internal::Handle<v8::internal::Object> obj)
  72     : value_(v8::internal::Handle<v8::internal::JSObject>::cast(obj)) { }
  73
  74
  75 NeanderObject::NeanderObject(v8::internal::Object* obj)
  76     : value_(v8::internal::Handle<v8::internal::JSObject>(
  77         v8::internal::JSObject::cast(obj))) { }
  78
  79
  80 NeanderArray::NeanderArray(v8::internal::Handle<v8::internal::Object> obj)
  81     : obj_(obj) { }
  82
  83
  84 v8::internal::Object* NeanderObject::get(int offset) {
  85   DCHECK(value()->HasFastObjectElements());
  86   return v8::internal::FixedArray::cast(value()->elements())->get(offset);
  87 }
  88
  89
  90 void NeanderObject::set(int offset, v8::internal::Object* value) {
  91   DCHECK(value_->HasFastObjectElements());
  92   v8::internal::FixedArray::cast(value_->elements())->set(offset, value);
  93 }
  94
  95
  96 template <typename T> inline T ToCData(v8::internal::Object* obj) {
  97   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
  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   return isolate->factory()->NewForeign(
 109       reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
 110 }
 111
 112
 113 class ApiFunction {
 114  public:
 115   explicit ApiFunction(v8::internal::Address addr) : addr_(addr) { }
 116   v8::internal::Address address() { return addr_; }
 117  private:
 118   v8::internal::Address addr_;
 119 };
 120
 121
 122
 123 class RegisteredExtension {
 124  public:
 125   explicit RegisteredExtension(Extension* extension);
 126   static void Register(RegisteredExtension* that);
 127   static void UnregisterAll();
 128   Extension* extension() { return extension_; }
 129   RegisteredExtension* next() { return next_; }
 130   static RegisteredExtension* first_extension() { return first_extension_; }
 131  private:
 132   Extension* extension_;
 133   RegisteredExtension* next_;
 134   static RegisteredExtension* first_extension_;
 135 };
 136
 137
 138 #define OPEN_HANDLE_LIST(V)                    \
 139   V(Template, TemplateInfo)                    \
 140   V(FunctionTemplate, FunctionTemplateInfo)    \
 141   V(ObjectTemplate, ObjectTemplateInfo)        \
 142   V(Signature, SignatureInfo)                  \
 143   V(AccessorSignature, FunctionTemplateInfo)   \
 144   V(TypeSwitch, TypeSwitchInfo)                \
 145   V(Data, Object)                              \
 146   V(RegExp, JSRegExp)                          \
 147   V(Object, JSObject)                          \
 148   V(Array, JSArray)                            \
 149   V(ArrayBuffer, JSArrayBuffer)                \
 150   V(ArrayBufferView, JSArrayBufferView)        \
 151   V(TypedArray, JSTypedArray)                  \
 152   V(Uint8Array, JSTypedArray)                  \
 153   V(Uint8ClampedArray, JSTypedArray)           \
 154   V(Int8Array, JSTypedArray)                   \
 155   V(Uint16Array, JSTypedArray)                 \
 156   V(Int16Array, JSTypedArray)                  \
 157   V(Uint32Array, JSTypedArray)                 \
 158   V(Int32Array, JSTypedArray)                  \
 159   V(Float32Array, JSTypedArray)                \
 160   V(Float32x4Array, JSTypedArray)              \
 161   V(Float64x2Array, JSTypedArray)              \
 162   V(Int32x4Array, JSTypedArray)                \
 163   V(Float64Array, JSTypedArray)                \
 164   V(DataView, JSDataView)                      \
 165   V(Name, Name)                                \
 166   V(String, String)                            \
 167   V(Symbol, Symbol)                            \
 168   V(Script, JSFunction)                        \
 169   V(UnboundScript, SharedFunctionInfo)         \
 170   V(Function, JSFunction)                      \
 171   V(Message, JSMessageObject)                  \
 172   V(Context, Context)                          \
 173   V(External, Object)                          \
 174   V(StackTrace, JSArray)                       \
 175   V(StackFrame, JSObject)                      \
 176   V(DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
 177
 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<ArrayBuffer> ToLocal(
 210       v8::internal::Handle<v8::internal::JSArrayBuffer> obj);
 211   static inline Local<ArrayBufferView> ToLocal(
 212       v8::internal::Handle<v8::internal::JSArrayBufferView> obj);
 213   static inline Local<DataView> ToLocal(
 214       v8::internal::Handle<v8::internal::JSDataView> obj);
 215
 216   static inline Local<TypedArray> ToLocal(
 217       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 218   static inline Local<Uint8Array> ToLocalUint8Array(
 219       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 220   static inline Local<Uint8ClampedArray> ToLocalUint8ClampedArray(
 221       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 222   static inline Local<Int8Array> ToLocalInt8Array(
 223       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 224   static inline Local<Uint16Array> ToLocalUint16Array(
 225       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 226   static inline Local<Int16Array> ToLocalInt16Array(
 227       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 228   static inline Local<Uint32Array> ToLocalUint32Array(
 229       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 230   static inline Local<Int32Array> ToLocalInt32Array(
 231       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 232   static inline Local<Float32Array> ToLocalFloat32Array(
 233       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 234   static inline Local<Float32x4Array> ToLocalFloat32x4Array(
 235       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 236   static inline Local<Float64x2Array> ToLocalFloat64x2Array(
 237       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 238   static inline Local<Int32x4Array> ToLocalInt32x4Array(
 239       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 240   static inline Local<Float64Array> ToLocalFloat64Array(
 241       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 242
 243   static inline Local<Message> MessageToLocal(
 244       v8::internal::Handle<v8::internal::Object> obj);
 245   static inline Local<Promise> PromiseToLocal(
 246       v8::internal::Handle<v8::internal::JSObject> obj);
 247   static inline Local<StackTrace> StackTraceToLocal(
 248       v8::internal::Handle<v8::internal::JSArray> obj);
 249   static inline Local<StackFrame> StackFrameToLocal(
 250       v8::internal::Handle<v8::internal::JSObject> obj);
 251   static inline Local<Number> NumberToLocal(
 252       v8::internal::Handle<v8::internal::Object> obj);
 253   static inline Local<Integer> IntegerToLocal(
 254       v8::internal::Handle<v8::internal::Object> obj);
 255   static inline Local<Uint32> Uint32ToLocal(
 256       v8::internal::Handle<v8::internal::Object> obj);
 257   static inline Local<FunctionTemplate> ToLocal(
 258       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 259   static inline Local<ObjectTemplate> ToLocal(
 260       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 261   static inline Local<Signature> ToLocal(
 262       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 263   static inline Local<AccessorSignature> AccessorSignatureToLocal(
 264       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 265   static inline Local<TypeSwitch> ToLocal(
 266       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 267   static inline Local<External> ExternalToLocal(
 268       v8::internal::Handle<v8::internal::JSObject> obj);
 269   static inline Local<DeclaredAccessorDescriptor> ToLocal(
 270       v8::internal::Handle<v8::internal::DeclaredAccessorDescriptor> obj);
 271
 272 #define DECLARE_OPEN_HANDLE(From, To) \
 273   static inline v8::internal::Handle<v8::internal::To> \
 274       OpenHandle(const From* that, bool allow_empty_handle = false);
 275
 276 OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 277
 278 #undef DECLARE_OPEN_HANDLE
 279
 280   template<class From, class To>
 281   static inline Local<To> Convert(v8::internal::Handle<From> obj) {
 282     DCHECK(obj.is_null() || !obj->IsTheHole());
 283     return Local<To>(reinterpret_cast<To*>(obj.location()));
 284   }
 285
 286   template <class T>
 287   static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
 288       const v8::Persistent<T>& persistent) {
 289     return v8::internal::Handle<v8::internal::Object>(
 290         reinterpret_cast<v8::internal::Object**>(persistent.val_));
 291   }
 292
 293   template <class T>
 294   static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
 295       v8::Persistent<T>* persistent) {
 296     return OpenPersistent(*persistent);
 297   }
 298
 299   template <class From, class To>
 300   static inline v8::internal::Handle<To> OpenHandle(v8::Local<From> handle) {
 301     return OpenHandle(*handle);
 302   }
 303
 304  private:
 305   static void ReportApiFailure(const char* location, const char* message);
 306 };
 307
 308
 309 template <class T>
 310 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 311     v8::EscapableHandleScope* scope) {
 312   v8::internal::Handle<T> handle;
 313   if (!is_null()) {
 314     handle = *this;
 315   }
 316   return Utils::OpenHandle(*scope->Escape(Utils::ToLocal(handle)), true);
 317 }
 318
 319
 320 template <class T>
 321 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 322   return reinterpret_cast<T*>(obj.location());
 323 }
 324
 325 template <class T>
 326 inline v8::Local<T> ToApiHandle(
 327     v8::internal::Handle<v8::internal::Object> obj) {
 328   return Utils::Convert<v8::internal::Object, T>(obj);
 329 }
 330
 331
 332 // Implementations of ToLocal
 333
 334 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 335   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 336     return Convert<v8::internal::From, v8::To>(obj);  \
 337   }
 338
 339
 340 #define MAKE_TO_LOCAL_TYPED_ARRAY(Type, typeName, TYPE, ctype, size)        \
 341   Local<v8::Type##Array> Utils::ToLocal##Type##Array(                       \
 342       v8::internal::Handle<v8::internal::JSTypedArray> obj) {               \
 343     DCHECK(obj->type() == kExternal##Type##Array);                          \
 344     return Convert<v8::internal::JSTypedArray, v8::Type##Array>(obj);       \
 345   }
 346
 347
 348 MAKE_TO_LOCAL(ToLocal, Context, Context)
 349 MAKE_TO_LOCAL(ToLocal, Object, Value)
 350 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 351 MAKE_TO_LOCAL(ToLocal, Name, Name)
 352 MAKE_TO_LOCAL(ToLocal, String, String)
 353 MAKE_TO_LOCAL(ToLocal, Symbol, Symbol)
 354 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 355 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 356 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 357 MAKE_TO_LOCAL(ToLocal, JSArrayBuffer, ArrayBuffer)
 358 MAKE_TO_LOCAL(ToLocal, JSArrayBufferView, ArrayBufferView)
 359 MAKE_TO_LOCAL(ToLocal, JSDataView, DataView)
 360 MAKE_TO_LOCAL(ToLocal, JSTypedArray, TypedArray)
 361
 362 TYPED_ARRAYS(MAKE_TO_LOCAL_TYPED_ARRAY)
 363
 364 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
 365 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
 366 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
 367 MAKE_TO_LOCAL(AccessorSignatureToLocal, FunctionTemplateInfo, AccessorSignature)
 368 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 369 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 370 MAKE_TO_LOCAL(PromiseToLocal, JSObject, Promise)
 371 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 372 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 373 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 374 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 375 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 376 MAKE_TO_LOCAL(ExternalToLocal, JSObject, External)
 377 MAKE_TO_LOCAL(ToLocal, DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
 378
 379 #undef MAKE_TO_LOCAL_TYPED_ARRAY
 380 #undef MAKE_TO_LOCAL
 381
 382
 383 // Implementations of OpenHandle
 384
 385 #define MAKE_OPEN_HANDLE(From, To)                                          \
 386   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(                 \
 387     const v8::From* that, bool allow_empty_handle) {                        \
 388     EXTRA_CHECK(allow_empty_handle || that != NULL);                        \
 389     EXTRA_CHECK(that == NULL ||                                             \
 390         (*reinterpret_cast<v8::internal::Object* const*>(that))->Is##To()); \
 391     return v8::internal::Handle<v8::internal::To>(                          \
 392         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 393   }
 394
 395 OPEN_HANDLE_LIST(MAKE_OPEN_HANDLE)
 396
 397 #undef MAKE_OPEN_HANDLE
 398 #undef OPEN_HANDLE_LIST
 399
 400
 401 namespace internal {
 402
 403 // Tracks string usage to help make better decisions when
 404 // externalizing strings.
 405 //
 406 // Implementation note: internally this class only tracks fresh
 407 // strings and keeps a single use counter for them.
 408 class StringTracker {
 409  public:
 410   // Records that the given string's characters were copied to some
 411   // external buffer. If this happens often we should honor
 412   // externalization requests for the string.
 413   void RecordWrite(Handle<String> string) {
 414     Address address = reinterpret_cast<Address>(*string);
 415     Address top = isolate_->heap()->NewSpaceTop();
 416     if (IsFreshString(address, top)) {
 417       IncrementUseCount(top);
 418     }
 419   }
 420
 421   // Estimates freshness and use frequency of the given string based
 422   // on how close it is to the new space top and the recorded usage
 423   // history.
 424   inline bool IsFreshUnusedString(Handle<String> string) {
 425     Address address = reinterpret_cast<Address>(*string);
 426     Address top = isolate_->heap()->NewSpaceTop();
 427     return IsFreshString(address, top) && IsUseCountLow(top);
 428   }
 429
 430  private:
 431   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 432
 433   static inline bool IsFreshString(Address string, Address top) {
 434     return top - kFreshnessLimit <= string && string <= top;
 435   }
 436
 437   inline bool IsUseCountLow(Address top) {
 438     if (last_top_ != top) return true;
 439     return use_count_ < kUseLimit;
 440   }
 441
 442   inline void IncrementUseCount(Address top) {
 443     if (last_top_ != top) {
 444       use_count_ = 0;
 445       last_top_ = top;
 446     }
 447     ++use_count_;
 448   }
 449
 450   // Single use counter shared by all fresh strings.
 451   int use_count_;
 452
 453   // Last new space top when the use count above was valid.
 454   Address last_top_;
 455
 456   Isolate* isolate_;
 457
 458   // How close to the new space top a fresh string has to be.
 459   static const int kFreshnessLimit = 1024;
 460
 461   // The number of uses required to consider a string useful.
 462   static const int kUseLimit = 32;
 463
 464   friend class Isolate;
 465
 466   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 467 };
 468
 469
 470 class DeferredHandles {
 471  public:
 472   ~DeferredHandles();
 473
 474  private:
 475   DeferredHandles(Object** first_block_limit, Isolate* isolate)
 476       : next_(NULL),
 477         previous_(NULL),
 478         first_block_limit_(first_block_limit),
 479         isolate_(isolate) {
 480     isolate->LinkDeferredHandles(this);
 481   }
 482
 483   void Iterate(ObjectVisitor* v);
 484
 485   List<Object**> blocks_;
 486   DeferredHandles* next_;
 487   DeferredHandles* previous_;
 488   Object** first_block_limit_;
 489   Isolate* isolate_;
 490
 491   friend class HandleScopeImplementer;
 492   friend class Isolate;
 493 };
 494
 495
 496 // This class is here in order to be able to declare it a friend of
 497 // HandleScope.  Moving these methods to be members of HandleScope would be
 498 // neat in some ways, but it would expose internal implementation details in
 499 // our public header file, which is undesirable.
 500 //
 501 // An isolate has a single instance of this class to hold the current thread's
 502 // data. In multithreaded V8 programs this data is copied in and out of storage
 503 // so that the currently executing thread always has its own copy of this
 504 // data.
 505 class HandleScopeImplementer {
 506  public:
 507   explicit HandleScopeImplementer(Isolate* isolate)
 508       : isolate_(isolate),
 509         blocks_(0),
 510         entered_contexts_(0),
 511         saved_contexts_(0),
 512         spare_(NULL),
 513         call_depth_(0),
 514         last_handle_before_deferred_block_(NULL) { }
 515
 516   ~HandleScopeImplementer() {
 517     DeleteArray(spare_);
 518   }
 519
 520   // Threading support for handle data.
 521   static int ArchiveSpacePerThread();
 522   char* RestoreThread(char* from);
 523   char* ArchiveThread(char* to);
 524   void FreeThreadResources();
 525
 526   // Garbage collection support.
 527   void Iterate(v8::internal::ObjectVisitor* v);
 528   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 529
 530
 531   inline internal::Object** GetSpareOrNewBlock();
 532   inline void DeleteExtensions(internal::Object** prev_limit);
 533
 534   inline void IncrementCallDepth() {call_depth_++;}
 535   inline void DecrementCallDepth() {call_depth_--;}
 536   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 537
 538   inline void EnterContext(Handle<Context> context);
 539   inline void LeaveContext();
 540   inline bool LastEnteredContextWas(Handle<Context> context);
 541
 542   // Returns the last entered context or an empty handle if no
 543   // contexts have been entered.
 544   inline Handle<Context> LastEnteredContext();
 545
 546   inline void SaveContext(Context* context);
 547   inline Context* RestoreContext();
 548   inline bool HasSavedContexts();
 549
 550   inline List<internal::Object**>* blocks() { return &blocks_; }
 551   Isolate* isolate() const { return isolate_; }
 552
 553   void ReturnBlock(Object** block) {
 554     DCHECK(block != NULL);
 555     if (spare_ != NULL) DeleteArray(spare_);
 556     spare_ = block;
 557   }
 558
 559  private:
 560   void ResetAfterArchive() {
 561     blocks_.Initialize(0);
 562     entered_contexts_.Initialize(0);
 563     saved_contexts_.Initialize(0);
 564     spare_ = NULL;
 565     last_handle_before_deferred_block_ = NULL;
 566     call_depth_ = 0;
 567   }
 568
 569   void Free() {
 570     DCHECK(blocks_.length() == 0);
 571     DCHECK(entered_contexts_.length() == 0);
 572     DCHECK(saved_contexts_.length() == 0);
 573     blocks_.Free();
 574     entered_contexts_.Free();
 575     saved_contexts_.Free();
 576     if (spare_ != NULL) {
 577       DeleteArray(spare_);
 578       spare_ = NULL;
 579     }
 580     DCHECK(call_depth_ == 0);
 581   }
 582
 583   void BeginDeferredScope();
 584   DeferredHandles* Detach(Object** prev_limit);
 585
 586   Isolate* isolate_;
 587   List<internal::Object**> blocks_;
 588   // Used as a stack to keep track of entered contexts.
 589   List<Context*> entered_contexts_;
 590   // Used as a stack to keep track of saved contexts.
 591   List<Context*> saved_contexts_;
 592   Object** spare_;
 593   int call_depth_;
 594   Object** last_handle_before_deferred_block_;
 595   // This is only used for threading support.
 596   HandleScopeData handle_scope_data_;
 597
 598   void IterateThis(ObjectVisitor* v);
 599   char* RestoreThreadHelper(char* from);
 600   char* ArchiveThreadHelper(char* to);
 601
 602   friend class DeferredHandles;
 603   friend class DeferredHandleScope;
 604
 605   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 606 };
 607
 608
 609 const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 610
 611
 612 void HandleScopeImplementer::SaveContext(Context* context) {
 613   saved_contexts_.Add(context);
 614 }
 615
 616
 617 Context* HandleScopeImplementer::RestoreContext() {
 618   return saved_contexts_.RemoveLast();
 619 }
 620
 621
 622 bool HandleScopeImplementer::HasSavedContexts() {
 623   return !saved_contexts_.is_empty();
 624 }
 625
 626
 627 void HandleScopeImplementer::EnterContext(Handle<Context> context) {
 628   entered_contexts_.Add(*context);
 629 }
 630
 631
 632 void HandleScopeImplementer::LeaveContext() {
 633   entered_contexts_.RemoveLast();
 634 }
 635
 636
 637 bool HandleScopeImplementer::LastEnteredContextWas(Handle<Context> context) {
 638   return !entered_contexts_.is_empty() && entered_contexts_.last() == *context;
 639 }
 640
 641
 642 Handle<Context> HandleScopeImplementer::LastEnteredContext() {
 643   if (entered_contexts_.is_empty()) return Handle<Context>::null();
 644   return Handle<Context>(entered_contexts_.last());
 645 }
 646
 647
 648 // If there's a spare block, use it for growing the current scope.
 649 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 650   internal::Object** block = (spare_ != NULL) ?
 651       spare_ :
 652       NewArray<internal::Object*>(kHandleBlockSize);
 653   spare_ = NULL;
 654   return block;
 655 }
 656
 657
 658 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 659   while (!blocks_.is_empty()) {
 660     internal::Object** block_start = blocks_.last();
 661     internal::Object** block_limit = block_start + kHandleBlockSize;
 662 #ifdef DEBUG
 663     // SealHandleScope may make the prev_limit to point inside the block.
 664     if (block_start <= prev_limit && prev_limit <= block_limit) {
 665 #ifdef ENABLE_HANDLE_ZAPPING
 666       internal::HandleScope::ZapRange(prev_limit, block_limit);
 667 #endif
 668       break;
 669     }
 670 #else
 671     if (prev_limit == block_limit) break;
 672 #endif
 673
 674     blocks_.RemoveLast();
 675 #ifdef ENABLE_HANDLE_ZAPPING
 676     internal::HandleScope::ZapRange(block_start, block_limit);
 677 #endif
 678     if (spare_ != NULL) {
 679       DeleteArray(spare_);
 680     }
 681     spare_ = block_start;
 682   }
 683   DCHECK((blocks_.is_empty() && prev_limit == NULL) ||
 684          (!blocks_.is_empty() && prev_limit != NULL));
 685 }
 686
 687
 688 // Interceptor functions called from generated inline caches to notify
 689 // CPU profiler that external callbacks are invoked.
 690 void InvokeAccessorGetterCallback(
 691     v8::Local<v8::Name> property,
 692     const v8::PropertyCallbackInfo<v8::Value>& info,
 693     v8::AccessorNameGetterCallback getter);
 694
 695 void InvokeFunctionCallback(const v8::FunctionCallbackInfo<v8::Value>& info,
 696                             v8::FunctionCallback callback);
 697
 698 class Testing {
 699  public:
 700   static v8::Testing::StressType stress_type() { return stress_type_; }
 701   static void set_stress_type(v8::Testing::StressType stress_type) {
 702     stress_type_ = stress_type;
 703   }
 704
 705  private:
 706   static v8::Testing::StressType stress_type_;
 707 };
 708
 709 } }  // namespace v8::internal
 710
 711 #endif  // V8_API_H_