src/api.h

   1 // Copyright 2012 the V8 project authors. All rights reserved.
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  27
  28 #ifndef V8_API_H_
  29 #define V8_API_H_
  30
  31 #include "v8.h"
  32
  33 #include "../include/v8-testing.h"
  34 #include "apiutils.h"
  35 #include "contexts.h"
  36 #include "factory.h"
  37 #include "isolate.h"
  38 #include "list-inl.h"
  39
  40 namespace v8 {
  41
  42 // Constants used in the implementation of the API.  The most natural thing
  43 // would usually be to place these with the classes that use them, but
  44 // we want to keep them out of v8.h because it is an externally
  45 // visible file.
  46 class Consts {
  47  public:
  48   enum TemplateType {
  49     FUNCTION_TEMPLATE = 0,
  50     OBJECT_TEMPLATE = 1
  51   };
  52 };
  53
  54
  55 // Utilities for working with neander-objects, primitive
  56 // env-independent JSObjects used by the api.
  57 class NeanderObject {
  58  public:
  59   explicit NeanderObject(v8::internal::Isolate* isolate, int size);
  60   explicit inline NeanderObject(v8::internal::Handle<v8::internal::Object> obj);
  61   explicit inline NeanderObject(v8::internal::Object* obj);
  62   inline v8::internal::Object* get(int index);
  63   inline void set(int index, v8::internal::Object* value);
  64   inline v8::internal::Handle<v8::internal::JSObject> value() { return value_; }
  65   int size();
  66  private:
  67   v8::internal::Handle<v8::internal::JSObject> value_;
  68 };
  69
  70
  71 // Utilities for working with neander-arrays, a simple extensible
  72 // array abstraction built on neander-objects.
  73 class NeanderArray {
  74  public:
  75   explicit NeanderArray(v8::internal::Isolate* isolate);
  76   explicit inline NeanderArray(v8::internal::Handle<v8::internal::Object> obj);
  77   inline v8::internal::Handle<v8::internal::JSObject> value() {
  78     return obj_.value();
  79   }
  80
  81   void add(v8::internal::Handle<v8::internal::Object> value);
  82
  83   int length();
  84
  85   v8::internal::Object* get(int index);
  86   // Change the value at an index to undefined value. If the index is
  87   // out of bounds, the request is ignored. Returns the old value.
  88   void set(int index, v8::internal::Object* value);
  89  private:
  90   NeanderObject obj_;
  91 };
  92
  93
  94 NeanderObject::NeanderObject(v8::internal::Handle<v8::internal::Object> obj)
  95     : value_(v8::internal::Handle<v8::internal::JSObject>::cast(obj)) { }
  96
  97
  98 NeanderObject::NeanderObject(v8::internal::Object* obj)
  99     : value_(v8::internal::Handle<v8::internal::JSObject>(
 100         v8::internal::JSObject::cast(obj))) { }
 101
 102
 103 NeanderArray::NeanderArray(v8::internal::Handle<v8::internal::Object> obj)
 104     : obj_(obj) { }
 105
 106
 107 v8::internal::Object* NeanderObject::get(int offset) {
 108   ASSERT(value()->HasFastObjectElements());
 109   return v8::internal::FixedArray::cast(value()->elements())->get(offset);
 110 }
 111
 112
 113 void NeanderObject::set(int offset, v8::internal::Object* value) {
 114   ASSERT(value_->HasFastObjectElements());
 115   v8::internal::FixedArray::cast(value_->elements())->set(offset, value);
 116 }
 117
 118
 119 template <typename T> inline T ToCData(v8::internal::Object* obj) {
 120   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
 121   return reinterpret_cast<T>(
 122       reinterpret_cast<intptr_t>(
 123           v8::internal::Foreign::cast(obj)->foreign_address()));
 124 }
 125
 126
 127 template <typename T>
 128 inline v8::internal::Handle<v8::internal::Object> FromCData(
 129     v8::internal::Isolate* isolate, T obj) {
 130   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
 131   return isolate->factory()->NewForeign(
 132       reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
 133 }
 134
 135
 136 class ApiFunction {
 137  public:
 138   explicit ApiFunction(v8::internal::Address addr) : addr_(addr) { }
 139   v8::internal::Address address() { return addr_; }
 140  private:
 141   v8::internal::Address addr_;
 142 };
 143
 144
 145
 146 class RegisteredExtension {
 147  public:
 148   explicit RegisteredExtension(Extension* extension);
 149   static void Register(RegisteredExtension* that);
 150   static void UnregisterAll();
 151   Extension* extension() { return extension_; }
 152   RegisteredExtension* next() { return next_; }
 153   static RegisteredExtension* first_extension() { return first_extension_; }
 154  private:
 155   Extension* extension_;
 156   RegisteredExtension* next_;
 157   static RegisteredExtension* first_extension_;
 158 };
 159
 160
 161 #define OPEN_HANDLE_LIST(V)                    \
 162   V(Template, TemplateInfo)                    \
 163   V(FunctionTemplate, FunctionTemplateInfo)    \
 164   V(ObjectTemplate, ObjectTemplateInfo)        \
 165   V(Signature, SignatureInfo)                  \
 166   V(AccessorSignature, FunctionTemplateInfo)   \
 167   V(TypeSwitch, TypeSwitchInfo)                \
 168   V(Data, Object)                              \
 169   V(RegExp, JSRegExp)                          \
 170   V(Object, JSObject)                          \
 171   V(Array, JSArray)                            \
 172   V(ArrayBuffer, JSArrayBuffer)                \
 173   V(ArrayBufferView, JSArrayBufferView)        \
 174   V(TypedArray, JSTypedArray)                  \
 175   V(Uint8Array, JSTypedArray)                  \
 176   V(Uint8ClampedArray, JSTypedArray)           \
 177   V(Int8Array, JSTypedArray)                   \
 178   V(Uint16Array, JSTypedArray)                 \
 179   V(Int16Array, JSTypedArray)                  \
 180   V(Uint32Array, JSTypedArray)                 \
 181   V(Int32Array, JSTypedArray)                  \
 182   V(Float32Array, JSTypedArray)                \
 183   V(Float64Array, JSTypedArray)                \
 184   V(DataView, JSDataView)                      \
 185   V(String, String)                            \
 186   V(Symbol, Symbol)                            \
 187   V(Script, Object)                            \
 188   V(Function, JSFunction)                      \
 189   V(Message, JSObject)                         \
 190   V(Context, Context)                          \
 191   V(External, Foreign)                         \
 192   V(StackTrace, JSArray)                       \
 193   V(StackFrame, JSObject)                      \
 194   V(DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
 195
 196
 197 class Utils {
 198  public:
 199   static inline bool ApiCheck(bool condition,
 200                               const char* location,
 201                               const char* message) {
 202     if (!condition) Utils::ReportApiFailure(location, message);
 203     return condition;
 204   }
 205
 206   static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
 207   static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
 208
 209   static inline Local<Context> ToLocal(
 210       v8::internal::Handle<v8::internal::Context> obj);
 211   static inline Local<Value> ToLocal(
 212       v8::internal::Handle<v8::internal::Object> obj);
 213   static inline Local<Function> ToLocal(
 214       v8::internal::Handle<v8::internal::JSFunction> obj);
 215   static inline Local<String> ToLocal(
 216       v8::internal::Handle<v8::internal::String> obj);
 217   static inline Local<Symbol> ToLocal(
 218       v8::internal::Handle<v8::internal::Symbol> obj);
 219   static inline Local<RegExp> ToLocal(
 220       v8::internal::Handle<v8::internal::JSRegExp> obj);
 221   static inline Local<Object> ToLocal(
 222       v8::internal::Handle<v8::internal::JSObject> obj);
 223   static inline Local<Array> ToLocal(
 224       v8::internal::Handle<v8::internal::JSArray> obj);
 225   static inline Local<ArrayBuffer> ToLocal(
 226       v8::internal::Handle<v8::internal::JSArrayBuffer> obj);
 227   static inline Local<ArrayBufferView> ToLocal(
 228       v8::internal::Handle<v8::internal::JSArrayBufferView> obj);
 229   static inline Local<DataView> ToLocal(
 230       v8::internal::Handle<v8::internal::JSDataView> obj);
 231
 232   static inline Local<TypedArray> ToLocal(
 233       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 234   static inline Local<Uint8Array> ToLocalUint8Array(
 235       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 236   static inline Local<Uint8ClampedArray> ToLocalUint8ClampedArray(
 237       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 238   static inline Local<Int8Array> ToLocalInt8Array(
 239       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 240   static inline Local<Uint16Array> ToLocalUint16Array(
 241       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 242   static inline Local<Int16Array> ToLocalInt16Array(
 243       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 244   static inline Local<Uint32Array> ToLocalUint32Array(
 245       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 246   static inline Local<Int32Array> ToLocalInt32Array(
 247       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 248   static inline Local<Float32Array> ToLocalFloat32Array(
 249       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 250   static inline Local<Float64Array> ToLocalFloat64Array(
 251       v8::internal::Handle<v8::internal::JSTypedArray> obj);
 252
 253   static inline Local<Message> MessageToLocal(
 254       v8::internal::Handle<v8::internal::Object> obj);
 255   static inline Local<StackTrace> StackTraceToLocal(
 256       v8::internal::Handle<v8::internal::JSArray> obj);
 257   static inline Local<StackFrame> StackFrameToLocal(
 258       v8::internal::Handle<v8::internal::JSObject> obj);
 259   static inline Local<Number> NumberToLocal(
 260       v8::internal::Handle<v8::internal::Object> obj);
 261   static inline Local<Integer> IntegerToLocal(
 262       v8::internal::Handle<v8::internal::Object> obj);
 263   static inline Local<Uint32> Uint32ToLocal(
 264       v8::internal::Handle<v8::internal::Object> obj);
 265   static inline Local<FunctionTemplate> ToLocal(
 266       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 267   static inline Local<ObjectTemplate> ToLocal(
 268       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 269   static inline Local<Signature> ToLocal(
 270       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 271   static inline Local<AccessorSignature> AccessorSignatureToLocal(
 272       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 273   static inline Local<TypeSwitch> ToLocal(
 274       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 275   static inline Local<External> ExternalToLocal(
 276       v8::internal::Handle<v8::internal::JSObject> obj);
 277   static inline Local<DeclaredAccessorDescriptor> ToLocal(
 278       v8::internal::Handle<v8::internal::DeclaredAccessorDescriptor> obj);
 279
 280 #define DECLARE_OPEN_HANDLE(From, To) \
 281   static inline v8::internal::Handle<v8::internal::To> \
 282       OpenHandle(const From* that, bool allow_empty_handle = false);
 283
 284 OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 285
 286 #undef DECLARE_OPEN_HANDLE
 287
 288   template<class From, class To>
 289   static inline Local<To> Convert(v8::internal::Handle<From> obj) {
 290     ASSERT(obj.is_null() || !obj->IsTheHole());
 291     return Local<To>(reinterpret_cast<To*>(obj.location()));
 292   }
 293
 294   template <class T>
 295   static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
 296       const v8::Persistent<T>& persistent) {
 297     return v8::internal::Handle<v8::internal::Object>(
 298         reinterpret_cast<v8::internal::Object**>(persistent.val_));
 299   }
 300
 301   template <class T>
 302   static inline v8::internal::Handle<v8::internal::Object> OpenPersistent(
 303       v8::Persistent<T>* persistent) {
 304     return OpenPersistent(*persistent);
 305   }
 306
 307   template <class From, class To>
 308   static inline v8::internal::Handle<To> OpenHandle(v8::Local<From> handle) {
 309     return OpenHandle(*handle);
 310   }
 311
 312  private:
 313   static void ReportApiFailure(const char* location, const char* message);
 314 };
 315
 316
 317 template <class T>
 318 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 319     v8::EscapableHandleScope* scope) {
 320   v8::internal::Handle<T> handle;
 321   if (!is_null()) {
 322     handle = *this;
 323   }
 324   return Utils::OpenHandle(*scope->Escape(Utils::ToLocal(handle)), true);
 325 }
 326
 327
 328 template <class T>
 329 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 330   return reinterpret_cast<T*>(obj.location());
 331 }
 332
 333 template <class T>
 334 inline v8::Local<T> ToApiHandle(
 335     v8::internal::Handle<v8::internal::Object> obj) {
 336   return Utils::Convert<v8::internal::Object, T>(obj);
 337 }
 338
 339
 340 // Implementations of ToLocal
 341
 342 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 343   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 344     return Convert<v8::internal::From, v8::To>(obj);  \
 345   }
 346
 347
 348 #define MAKE_TO_LOCAL_TYPED_ARRAY(TypedArray, typeConst)                    \
 349   Local<v8::TypedArray> Utils::ToLocal##TypedArray(                         \
 350       v8::internal::Handle<v8::internal::JSTypedArray> obj) {               \
 351     ASSERT(obj->type() == typeConst);                                       \
 352     return Convert<v8::internal::JSTypedArray, v8::TypedArray>(obj);        \
 353   }
 354
 355
 356 MAKE_TO_LOCAL(ToLocal, Context, Context)
 357 MAKE_TO_LOCAL(ToLocal, Object, Value)
 358 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 359 MAKE_TO_LOCAL(ToLocal, String, String)
 360 MAKE_TO_LOCAL(ToLocal, Symbol, Symbol)
 361 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 362 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 363 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 364 MAKE_TO_LOCAL(ToLocal, JSArrayBuffer, ArrayBuffer)
 365 MAKE_TO_LOCAL(ToLocal, JSArrayBufferView, ArrayBufferView)
 366 MAKE_TO_LOCAL(ToLocal, JSDataView, DataView)
 367 MAKE_TO_LOCAL(ToLocal, JSTypedArray, TypedArray)
 368
 369 MAKE_TO_LOCAL_TYPED_ARRAY(Uint8Array, kExternalUnsignedByteArray)
 370 MAKE_TO_LOCAL_TYPED_ARRAY(Uint8ClampedArray, kExternalPixelArray)
 371 MAKE_TO_LOCAL_TYPED_ARRAY(Int8Array, kExternalByteArray)
 372 MAKE_TO_LOCAL_TYPED_ARRAY(Uint16Array, kExternalUnsignedShortArray)
 373 MAKE_TO_LOCAL_TYPED_ARRAY(Int16Array, kExternalShortArray)
 374 MAKE_TO_LOCAL_TYPED_ARRAY(Uint32Array, kExternalUnsignedIntArray)
 375 MAKE_TO_LOCAL_TYPED_ARRAY(Int32Array, kExternalIntArray)
 376 MAKE_TO_LOCAL_TYPED_ARRAY(Float32Array, kExternalFloatArray)
 377 MAKE_TO_LOCAL_TYPED_ARRAY(Float64Array, kExternalDoubleArray)
 378
 379 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
 380 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
 381 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
 382 MAKE_TO_LOCAL(AccessorSignatureToLocal, FunctionTemplateInfo, AccessorSignature)
 383 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 384 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 385 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 386 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 387 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 388 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 389 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 390 MAKE_TO_LOCAL(ExternalToLocal, JSObject, External)
 391 MAKE_TO_LOCAL(ToLocal, DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
 392
 393 #undef MAKE_TO_LOCAL_TYPED_ARRAY
 394 #undef MAKE_TO_LOCAL
 395
 396
 397 // Implementations of OpenHandle
 398
 399 #define MAKE_OPEN_HANDLE(From, To)                                          \
 400   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(                 \
 401     const v8::From* that, bool allow_empty_handle) {                        \
 402     EXTRA_CHECK(allow_empty_handle || that != NULL);                        \
 403     EXTRA_CHECK(that == NULL ||                                             \
 404         !(*reinterpret_cast<v8::internal::To**>(                            \
 405             const_cast<v8::From*>(that)))->IsFailure());                    \
 406     return v8::internal::Handle<v8::internal::To>(                          \
 407         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 408   }
 409
 410 OPEN_HANDLE_LIST(MAKE_OPEN_HANDLE)
 411
 412 #undef MAKE_OPEN_HANDLE
 413 #undef OPEN_HANDLE_LIST
 414
 415
 416 namespace internal {
 417
 418 // Tracks string usage to help make better decisions when
 419 // externalizing strings.
 420 //
 421 // Implementation note: internally this class only tracks fresh
 422 // strings and keeps a single use counter for them.
 423 class StringTracker {
 424  public:
 425   // Records that the given string's characters were copied to some
 426   // external buffer. If this happens often we should honor
 427   // externalization requests for the string.
 428   void RecordWrite(Handle<String> string) {
 429     Address address = reinterpret_cast<Address>(*string);
 430     Address top = isolate_->heap()->NewSpaceTop();
 431     if (IsFreshString(address, top)) {
 432       IncrementUseCount(top);
 433     }
 434   }
 435
 436   // Estimates freshness and use frequency of the given string based
 437   // on how close it is to the new space top and the recorded usage
 438   // history.
 439   inline bool IsFreshUnusedString(Handle<String> string) {
 440     Address address = reinterpret_cast<Address>(*string);
 441     Address top = isolate_->heap()->NewSpaceTop();
 442     return IsFreshString(address, top) && IsUseCountLow(top);
 443   }
 444
 445  private:
 446   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 447
 448   static inline bool IsFreshString(Address string, Address top) {
 449     return top - kFreshnessLimit <= string && string <= top;
 450   }
 451
 452   inline bool IsUseCountLow(Address top) {
 453     if (last_top_ != top) return true;
 454     return use_count_ < kUseLimit;
 455   }
 456
 457   inline void IncrementUseCount(Address top) {
 458     if (last_top_ != top) {
 459       use_count_ = 0;
 460       last_top_ = top;
 461     }
 462     ++use_count_;
 463   }
 464
 465   // Single use counter shared by all fresh strings.
 466   int use_count_;
 467
 468   // Last new space top when the use count above was valid.
 469   Address last_top_;
 470
 471   Isolate* isolate_;
 472
 473   // How close to the new space top a fresh string has to be.
 474   static const int kFreshnessLimit = 1024;
 475
 476   // The number of uses required to consider a string useful.
 477   static const int kUseLimit = 32;
 478
 479   friend class Isolate;
 480
 481   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 482 };
 483
 484
 485 class DeferredHandles {
 486  public:
 487   ~DeferredHandles();
 488
 489  private:
 490   DeferredHandles(Object** first_block_limit, Isolate* isolate)
 491       : next_(NULL),
 492         previous_(NULL),
 493         first_block_limit_(first_block_limit),
 494         isolate_(isolate) {
 495     isolate->LinkDeferredHandles(this);
 496   }
 497
 498   void Iterate(ObjectVisitor* v);
 499
 500   List<Object**> blocks_;
 501   DeferredHandles* next_;
 502   DeferredHandles* previous_;
 503   Object** first_block_limit_;
 504   Isolate* isolate_;
 505
 506   friend class HandleScopeImplementer;
 507   friend class Isolate;
 508 };
 509
 510
 511 // This class is here in order to be able to declare it a friend of
 512 // HandleScope.  Moving these methods to be members of HandleScope would be
 513 // neat in some ways, but it would expose internal implementation details in
 514 // our public header file, which is undesirable.
 515 //
 516 // An isolate has a single instance of this class to hold the current thread's
 517 // data. In multithreaded V8 programs this data is copied in and out of storage
 518 // so that the currently executing thread always has its own copy of this
 519 // data.
 520 class HandleScopeImplementer {
 521  public:
 522   explicit HandleScopeImplementer(Isolate* isolate)
 523       : isolate_(isolate),
 524         blocks_(0),
 525         entered_contexts_(0),
 526         saved_contexts_(0),
 527         spare_(NULL),
 528         call_depth_(0),
 529         last_handle_before_deferred_block_(NULL) { }
 530
 531   ~HandleScopeImplementer() {
 532     DeleteArray(spare_);
 533   }
 534
 535   // Threading support for handle data.
 536   static int ArchiveSpacePerThread();
 537   char* RestoreThread(char* from);
 538   char* ArchiveThread(char* to);
 539   void FreeThreadResources();
 540
 541   // Garbage collection support.
 542   void Iterate(v8::internal::ObjectVisitor* v);
 543   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 544
 545
 546   inline internal::Object** GetSpareOrNewBlock();
 547   inline void DeleteExtensions(internal::Object** prev_limit);
 548
 549   inline void IncrementCallDepth() {call_depth_++;}
 550   inline void DecrementCallDepth() {call_depth_--;}
 551   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 552
 553   inline void EnterContext(Handle<Context> context);
 554   inline bool LeaveContext(Handle<Context> context);
 555
 556   // Returns the last entered context or an empty handle if no
 557   // contexts have been entered.
 558   inline Handle<Context> LastEnteredContext();
 559
 560   inline void SaveContext(Context* context);
 561   inline Context* RestoreContext();
 562   inline bool HasSavedContexts();
 563
 564   inline List<internal::Object**>* blocks() { return &blocks_; }
 565   Isolate* isolate() const { return isolate_; }
 566
 567   void ReturnBlock(Object** block) {
 568     ASSERT(block != NULL);
 569     if (spare_ != NULL) DeleteArray(spare_);
 570     spare_ = block;
 571   }
 572
 573  private:
 574   void ResetAfterArchive() {
 575     blocks_.Initialize(0);
 576     entered_contexts_.Initialize(0);
 577     saved_contexts_.Initialize(0);
 578     spare_ = NULL;
 579     last_handle_before_deferred_block_ = NULL;
 580     call_depth_ = 0;
 581   }
 582
 583   void Free() {
 584     ASSERT(blocks_.length() == 0);
 585     ASSERT(entered_contexts_.length() == 0);
 586     ASSERT(saved_contexts_.length() == 0);
 587     blocks_.Free();
 588     entered_contexts_.Free();
 589     saved_contexts_.Free();
 590     if (spare_ != NULL) {
 591       DeleteArray(spare_);
 592       spare_ = NULL;
 593     }
 594     ASSERT(call_depth_ == 0);
 595   }
 596
 597   void BeginDeferredScope();
 598   DeferredHandles* Detach(Object** prev_limit);
 599
 600   Isolate* isolate_;
 601   List<internal::Object**> blocks_;
 602   // Used as a stack to keep track of entered contexts.
 603   List<Context*> entered_contexts_;
 604   // Used as a stack to keep track of saved contexts.
 605   List<Context*> saved_contexts_;
 606   Object** spare_;
 607   int call_depth_;
 608   Object** last_handle_before_deferred_block_;
 609   // This is only used for threading support.
 610   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
 611
 612   void IterateThis(ObjectVisitor* v);
 613   char* RestoreThreadHelper(char* from);
 614   char* ArchiveThreadHelper(char* to);
 615
 616   friend class DeferredHandles;
 617   friend class DeferredHandleScope;
 618
 619   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 620 };
 621
 622
 623 const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 624
 625
 626 void HandleScopeImplementer::SaveContext(Context* context) {
 627   saved_contexts_.Add(context);
 628 }
 629
 630
 631 Context* HandleScopeImplementer::RestoreContext() {
 632   return saved_contexts_.RemoveLast();
 633 }
 634
 635
 636 bool HandleScopeImplementer::HasSavedContexts() {
 637   return !saved_contexts_.is_empty();
 638 }
 639
 640
 641 void HandleScopeImplementer::EnterContext(Handle<Context> context) {
 642   entered_contexts_.Add(*context);
 643 }
 644
 645
 646 bool HandleScopeImplementer::LeaveContext(Handle<Context> context) {
 647   if (entered_contexts_.is_empty()) return false;
 648   // TODO(dcarney): figure out what's wrong here
 649   // if (entered_contexts_.last() != *context) return false;
 650   entered_contexts_.RemoveLast();
 651   return true;
 652 }
 653
 654
 655 Handle<Context> HandleScopeImplementer::LastEnteredContext() {
 656   if (entered_contexts_.is_empty()) return Handle<Context>::null();
 657   return Handle<Context>(entered_contexts_.last());
 658 }
 659
 660
 661 // If there's a spare block, use it for growing the current scope.
 662 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 663   internal::Object** block = (spare_ != NULL) ?
 664       spare_ :
 665       NewArray<internal::Object*>(kHandleBlockSize);
 666   spare_ = NULL;
 667   return block;
 668 }
 669
 670
 671 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 672   while (!blocks_.is_empty()) {
 673     internal::Object** block_start = blocks_.last();
 674     internal::Object** block_limit = block_start + kHandleBlockSize;
 675 #ifdef DEBUG
 676     // SealHandleScope may make the prev_limit to point inside the block.
 677     if (block_start <= prev_limit && prev_limit <= block_limit) {
 678 #ifdef ENABLE_HANDLE_ZAPPING
 679       internal::HandleScope::ZapRange(prev_limit, block_limit);
 680 #endif
 681       break;
 682     }
 683 #else
 684     if (prev_limit == block_limit) break;
 685 #endif
 686
 687     blocks_.RemoveLast();
 688 #ifdef ENABLE_HANDLE_ZAPPING
 689     internal::HandleScope::ZapRange(block_start, block_limit);
 690 #endif
 691     if (spare_ != NULL) {
 692       DeleteArray(spare_);
 693     }
 694     spare_ = block_start;
 695   }
 696   ASSERT((blocks_.is_empty() && prev_limit == NULL) ||
 697          (!blocks_.is_empty() && prev_limit != NULL));
 698 }
 699
 700
 701 // Interceptor functions called from generated inline caches to notify
 702 // CPU profiler that external callbacks are invoked.
 703 void InvokeAccessorGetterCallback(
 704     v8::Local<v8::String> property,
 705     const v8::PropertyCallbackInfo<v8::Value>& info,
 706     v8::AccessorGetterCallback getter);
 707
 708 void InvokeFunctionCallback(const v8::FunctionCallbackInfo<v8::Value>& info,
 709                             v8::FunctionCallback callback);
 710
 711 class Testing {
 712  public:
 713   static v8::Testing::StressType stress_type() { return stress_type_; }
 714   static void set_stress_type(v8::Testing::StressType stress_type) {
 715     stress_type_ = stress_type;
 716   }
 717
 718  private:
 719   static v8::Testing::StressType stress_type_;
 720 };
 721
 722 } }  // namespace v8::internal
 723
 724 #endif  // V8_API_H_