src/api.h

   1 // Copyright 2011 the V8 project authors. All rights reserved.
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   5 //
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  27
  28 #ifndef V8_API_H_
  29 #define V8_API_H_
  30
  31 #include "apiutils.h"
  32 #include "factory.h"
  33
  34 #include "../include/v8-testing.h"
  35
  36 namespace v8 {
  37
  38 // Constants used in the implementation of the API.  The most natural thing
  39 // would usually be to place these with the classes that use them, but
  40 // we want to keep them out of v8.h because it is an externally
  41 // visible file.
  42 class Consts {
  43  public:
  44   enum TemplateType {
  45     FUNCTION_TEMPLATE = 0,
  46     OBJECT_TEMPLATE = 1
  47   };
  48 };
  49
  50
  51 // Utilities for working with neander-objects, primitive
  52 // env-independent JSObjects used by the api.
  53 class NeanderObject {
  54  public:
  55   explicit NeanderObject(int size);
  56   explicit inline NeanderObject(v8::internal::Handle<v8::internal::Object> obj);
  57   explicit inline NeanderObject(v8::internal::Object* obj);
  58   inline v8::internal::Object* get(int index);
  59   inline void set(int index, v8::internal::Object* value);
  60   inline v8::internal::Handle<v8::internal::JSObject> value() { return value_; }
  61   int size();
  62  private:
  63   v8::internal::Handle<v8::internal::JSObject> value_;
  64 };
  65
  66
  67 // Utilities for working with neander-arrays, a simple extensible
  68 // array abstraction built on neander-objects.
  69 class NeanderArray {
  70  public:
  71   NeanderArray();
  72   explicit inline NeanderArray(v8::internal::Handle<v8::internal::Object> obj);
  73   inline v8::internal::Handle<v8::internal::JSObject> value() {
  74     return obj_.value();
  75   }
  76
  77   void add(v8::internal::Handle<v8::internal::Object> value);
  78
  79   int length();
  80
  81   v8::internal::Object* get(int index);
  82   // Change the value at an index to undefined value. If the index is
  83   // out of bounds, the request is ignored. Returns the old value.
  84   void set(int index, v8::internal::Object* value);
  85  private:
  86   NeanderObject obj_;
  87 };
  88
  89
  90 NeanderObject::NeanderObject(v8::internal::Handle<v8::internal::Object> obj)
  91     : value_(v8::internal::Handle<v8::internal::JSObject>::cast(obj)) { }
  92
  93
  94 NeanderObject::NeanderObject(v8::internal::Object* obj)
  95     : value_(v8::internal::Handle<v8::internal::JSObject>(
  96         v8::internal::JSObject::cast(obj))) { }
  97
  98
  99 NeanderArray::NeanderArray(v8::internal::Handle<v8::internal::Object> obj)
 100     : obj_(obj) { }
 101
 102
 103 v8::internal::Object* NeanderObject::get(int offset) {
 104   ASSERT(value()->HasFastElements());
 105   return v8::internal::FixedArray::cast(value()->elements())->get(offset);
 106 }
 107
 108
 109 void NeanderObject::set(int offset, v8::internal::Object* value) {
 110   ASSERT(value_->HasFastElements());
 111   v8::internal::FixedArray::cast(value_->elements())->set(offset, value);
 112 }
 113
 114
 115 template <typename T> static inline T ToCData(v8::internal::Object* obj) {
 116   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
 117   return reinterpret_cast<T>(
 118       reinterpret_cast<intptr_t>(
 119           v8::internal::Foreign::cast(obj)->foreign_address()));
 120 }
 121
 122
 123 template <typename T>
 124 static inline v8::internal::Handle<v8::internal::Object> FromCData(T obj) {
 125   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
 126   return FACTORY->NewForeign(
 127       reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
 128 }
 129
 130
 131 class ApiFunction {
 132  public:
 133   explicit ApiFunction(v8::internal::Address addr) : addr_(addr) { }
 134   v8::internal::Address address() { return addr_; }
 135  private:
 136   v8::internal::Address addr_;
 137 };
 138
 139
 140 enum ExtensionTraversalState {
 141   UNVISITED, VISITED, INSTALLED
 142 };
 143
 144
 145 class RegisteredExtension {
 146  public:
 147   explicit RegisteredExtension(Extension* extension);
 148   static void Register(RegisteredExtension* that);
 149   Extension* extension() { return extension_; }
 150   RegisteredExtension* next() { return next_; }
 151   RegisteredExtension* next_auto() { return next_auto_; }
 152   ExtensionTraversalState state() { return state_; }
 153   void set_state(ExtensionTraversalState value) { state_ = value; }
 154   static RegisteredExtension* first_extension() { return first_extension_; }
 155  private:
 156   Extension* extension_;
 157   RegisteredExtension* next_;
 158   RegisteredExtension* next_auto_;
 159   ExtensionTraversalState state_;
 160   static RegisteredExtension* first_extension_;
 161 };
 162
 163
 164 class Utils {
 165  public:
 166   static bool ReportApiFailure(const char* location, const char* message);
 167
 168   static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
 169   static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
 170
 171   static inline Local<Context> ToLocal(
 172       v8::internal::Handle<v8::internal::Context> obj);
 173   static inline Local<Value> ToLocal(
 174       v8::internal::Handle<v8::internal::Object> obj);
 175   static inline Local<Function> ToLocal(
 176       v8::internal::Handle<v8::internal::JSFunction> obj);
 177   static inline Local<String> ToLocal(
 178       v8::internal::Handle<v8::internal::String> obj);
 179   static inline Local<RegExp> ToLocal(
 180       v8::internal::Handle<v8::internal::JSRegExp> obj);
 181   static inline Local<Object> ToLocal(
 182       v8::internal::Handle<v8::internal::JSObject> obj);
 183   static inline Local<Array> ToLocal(
 184       v8::internal::Handle<v8::internal::JSArray> obj);
 185   static inline Local<External> ToLocal(
 186       v8::internal::Handle<v8::internal::Foreign> obj);
 187   static inline Local<Message> MessageToLocal(
 188       v8::internal::Handle<v8::internal::Object> obj);
 189   static inline Local<StackTrace> StackTraceToLocal(
 190       v8::internal::Handle<v8::internal::JSArray> obj);
 191   static inline Local<StackFrame> StackFrameToLocal(
 192       v8::internal::Handle<v8::internal::JSObject> obj);
 193   static inline Local<Number> NumberToLocal(
 194       v8::internal::Handle<v8::internal::Object> obj);
 195   static inline Local<Integer> IntegerToLocal(
 196       v8::internal::Handle<v8::internal::Object> obj);
 197   static inline Local<Uint32> Uint32ToLocal(
 198       v8::internal::Handle<v8::internal::Object> obj);
 199   static inline Local<FunctionTemplate> ToLocal(
 200       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 201   static inline Local<ObjectTemplate> ToLocal(
 202       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 203   static inline Local<Signature> ToLocal(
 204       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 205   static inline Local<TypeSwitch> ToLocal(
 206       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 207
 208   static inline v8::internal::Handle<v8::internal::TemplateInfo>
 209       OpenHandle(const Template* that);
 210   static inline v8::internal::Handle<v8::internal::FunctionTemplateInfo>
 211       OpenHandle(const FunctionTemplate* that);
 212   static inline v8::internal::Handle<v8::internal::ObjectTemplateInfo>
 213       OpenHandle(const ObjectTemplate* that);
 214   static inline v8::internal::Handle<v8::internal::Object>
 215       OpenHandle(const Data* data);
 216   static inline v8::internal::Handle<v8::internal::JSRegExp>
 217       OpenHandle(const RegExp* data);
 218   static inline v8::internal::Handle<v8::internal::JSObject>
 219       OpenHandle(const v8::Object* data);
 220   static inline v8::internal::Handle<v8::internal::JSArray>
 221       OpenHandle(const v8::Array* data);
 222   static inline v8::internal::Handle<v8::internal::String>
 223       OpenHandle(const String* data);
 224   static inline v8::internal::Handle<v8::internal::Object>
 225       OpenHandle(const Script* data);
 226   static inline v8::internal::Handle<v8::internal::JSFunction>
 227       OpenHandle(const Function* data);
 228   static inline v8::internal::Handle<v8::internal::JSObject>
 229       OpenHandle(const Message* message);
 230   static inline v8::internal::Handle<v8::internal::JSArray>
 231       OpenHandle(const StackTrace* stack_trace);
 232   static inline v8::internal::Handle<v8::internal::JSObject>
 233       OpenHandle(const StackFrame* stack_frame);
 234   static inline v8::internal::Handle<v8::internal::Context>
 235       OpenHandle(const v8::Context* context);
 236   static inline v8::internal::Handle<v8::internal::SignatureInfo>
 237       OpenHandle(const v8::Signature* sig);
 238   static inline v8::internal::Handle<v8::internal::TypeSwitchInfo>
 239       OpenHandle(const v8::TypeSwitch* that);
 240   static inline v8::internal::Handle<v8::internal::Foreign>
 241       OpenHandle(const v8::External* that);
 242 };
 243
 244
 245 template <class T>
 246 static inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 247   return reinterpret_cast<T*>(obj.location());
 248 }
 249
 250
 251 template <class T>
 252 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 253     v8::HandleScope* scope) {
 254   v8::internal::Handle<T> handle;
 255   if (!is_null()) {
 256     handle = *this;
 257   }
 258   return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)));
 259 }
 260
 261
 262 // Implementations of ToLocal
 263
 264 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 265   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 266     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
 267     return Local<To>(reinterpret_cast<To*>(obj.location()));                \
 268   }
 269
 270 MAKE_TO_LOCAL(ToLocal, Context, Context)
 271 MAKE_TO_LOCAL(ToLocal, Object, Value)
 272 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 273 MAKE_TO_LOCAL(ToLocal, String, String)
 274 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 275 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 276 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 277 MAKE_TO_LOCAL(ToLocal, Foreign, External)
 278 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
 279 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
 280 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
 281 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 282 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 283 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 284 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 285 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 286 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 287 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 288
 289 #undef MAKE_TO_LOCAL
 290
 291
 292 // Implementations of OpenHandle
 293
 294 #define MAKE_OPEN_HANDLE(From, To) \
 295   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(\
 296     const v8::From* that) { \
 297     return v8::internal::Handle<v8::internal::To>( \
 298         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 299   }
 300
 301 MAKE_OPEN_HANDLE(Template, TemplateInfo)
 302 MAKE_OPEN_HANDLE(FunctionTemplate, FunctionTemplateInfo)
 303 MAKE_OPEN_HANDLE(ObjectTemplate, ObjectTemplateInfo)
 304 MAKE_OPEN_HANDLE(Signature, SignatureInfo)
 305 MAKE_OPEN_HANDLE(TypeSwitch, TypeSwitchInfo)
 306 MAKE_OPEN_HANDLE(Data, Object)
 307 MAKE_OPEN_HANDLE(RegExp, JSRegExp)
 308 MAKE_OPEN_HANDLE(Object, JSObject)
 309 MAKE_OPEN_HANDLE(Array, JSArray)
 310 MAKE_OPEN_HANDLE(String, String)
 311 MAKE_OPEN_HANDLE(Script, Object)
 312 MAKE_OPEN_HANDLE(Function, JSFunction)
 313 MAKE_OPEN_HANDLE(Message, JSObject)
 314 MAKE_OPEN_HANDLE(Context, Context)
 315 MAKE_OPEN_HANDLE(External, Foreign)
 316 MAKE_OPEN_HANDLE(StackTrace, JSArray)
 317 MAKE_OPEN_HANDLE(StackFrame, JSObject)
 318
 319 #undef MAKE_OPEN_HANDLE
 320
 321
 322 namespace internal {
 323
 324 // Tracks string usage to help make better decisions when
 325 // externalizing strings.
 326 //
 327 // Implementation note: internally this class only tracks fresh
 328 // strings and keeps a single use counter for them.
 329 class StringTracker {
 330  public:
 331   // Records that the given string's characters were copied to some
 332   // external buffer. If this happens often we should honor
 333   // externalization requests for the string.
 334   void RecordWrite(Handle<String> string) {
 335     Address address = reinterpret_cast<Address>(*string);
 336     Address top = isolate_->heap()->NewSpaceTop();
 337     if (IsFreshString(address, top)) {
 338       IncrementUseCount(top);
 339     }
 340   }
 341
 342   // Estimates freshness and use frequency of the given string based
 343   // on how close it is to the new space top and the recorded usage
 344   // history.
 345   inline bool IsFreshUnusedString(Handle<String> string) {
 346     Address address = reinterpret_cast<Address>(*string);
 347     Address top = isolate_->heap()->NewSpaceTop();
 348     return IsFreshString(address, top) && IsUseCountLow(top);
 349   }
 350
 351  private:
 352   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 353
 354   static inline bool IsFreshString(Address string, Address top) {
 355     return top - kFreshnessLimit <= string && string <= top;
 356   }
 357
 358   inline bool IsUseCountLow(Address top) {
 359     if (last_top_ != top) return true;
 360     return use_count_ < kUseLimit;
 361   }
 362
 363   inline void IncrementUseCount(Address top) {
 364     if (last_top_ != top) {
 365       use_count_ = 0;
 366       last_top_ = top;
 367     }
 368     ++use_count_;
 369   }
 370
 371   // Single use counter shared by all fresh strings.
 372   int use_count_;
 373
 374   // Last new space top when the use count above was valid.
 375   Address last_top_;
 376
 377   Isolate* isolate_;
 378
 379   // How close to the new space top a fresh string has to be.
 380   static const int kFreshnessLimit = 1024;
 381
 382   // The number of uses required to consider a string useful.
 383   static const int kUseLimit = 32;
 384
 385   friend class Isolate;
 386
 387   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 388 };
 389
 390
 391 // This class is here in order to be able to declare it a friend of
 392 // HandleScope.  Moving these methods to be members of HandleScope would be
 393 // neat in some ways, but it would expose internal implementation details in
 394 // our public header file, which is undesirable.
 395 //
 396 // An isolate has a single instance of this class to hold the current thread's
 397 // data. In multithreaded V8 programs this data is copied in and out of storage
 398 // so that the currently executing thread always has its own copy of this
 399 // data.
 400 class HandleScopeImplementer {
 401  public:
 402   explicit HandleScopeImplementer(Isolate* isolate)
 403       : isolate_(isolate),
 404         blocks_(0),
 405         entered_contexts_(0),
 406         saved_contexts_(0),
 407         spare_(NULL),
 408         call_depth_(0) { }
 409
 410   ~HandleScopeImplementer() {
 411     DeleteArray(spare_);
 412   }
 413
 414   // Threading support for handle data.
 415   static int ArchiveSpacePerThread();
 416   char* RestoreThread(char* from);
 417   char* ArchiveThread(char* to);
 418   void FreeThreadResources();
 419
 420   // Garbage collection support.
 421   void Iterate(v8::internal::ObjectVisitor* v);
 422   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 423
 424
 425   inline internal::Object** GetSpareOrNewBlock();
 426   inline void DeleteExtensions(internal::Object** prev_limit);
 427
 428   inline void IncrementCallDepth() {call_depth_++;}
 429   inline void DecrementCallDepth() {call_depth_--;}
 430   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 431
 432   inline void EnterContext(Handle<Object> context);
 433   inline bool LeaveLastContext();
 434
 435   // Returns the last entered context or an empty handle if no
 436   // contexts have been entered.
 437   inline Handle<Object> LastEnteredContext();
 438
 439   inline void SaveContext(Context* context);
 440   inline Context* RestoreContext();
 441   inline bool HasSavedContexts();
 442
 443   inline List<internal::Object**>* blocks() { return &blocks_; }
 444
 445  private:
 446   void ResetAfterArchive() {
 447     blocks_.Initialize(0);
 448     entered_contexts_.Initialize(0);
 449     saved_contexts_.Initialize(0);
 450     spare_ = NULL;
 451     call_depth_ = 0;
 452   }
 453
 454   void Free() {
 455     ASSERT(blocks_.length() == 0);
 456     ASSERT(entered_contexts_.length() == 0);
 457     ASSERT(saved_contexts_.length() == 0);
 458     blocks_.Free();
 459     entered_contexts_.Free();
 460     saved_contexts_.Free();
 461     if (spare_ != NULL) {
 462       DeleteArray(spare_);
 463       spare_ = NULL;
 464     }
 465     ASSERT(call_depth_ == 0);
 466   }
 467
 468   Isolate* isolate_;
 469   List<internal::Object**> blocks_;
 470   // Used as a stack to keep track of entered contexts.
 471   List<Handle<Object> > entered_contexts_;
 472   // Used as a stack to keep track of saved contexts.
 473   List<Context*> saved_contexts_;
 474   Object** spare_;
 475   int call_depth_;
 476   // This is only used for threading support.
 477   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
 478
 479   void IterateThis(ObjectVisitor* v);
 480   char* RestoreThreadHelper(char* from);
 481   char* ArchiveThreadHelper(char* to);
 482
 483   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 484 };
 485
 486
 487 static const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 488
 489
 490 void HandleScopeImplementer::SaveContext(Context* context) {
 491   saved_contexts_.Add(context);
 492 }
 493
 494
 495 Context* HandleScopeImplementer::RestoreContext() {
 496   return saved_contexts_.RemoveLast();
 497 }
 498
 499
 500 bool HandleScopeImplementer::HasSavedContexts() {
 501   return !saved_contexts_.is_empty();
 502 }
 503
 504
 505 void HandleScopeImplementer::EnterContext(Handle<Object> context) {
 506   entered_contexts_.Add(context);
 507 }
 508
 509
 510 bool HandleScopeImplementer::LeaveLastContext() {
 511   if (entered_contexts_.is_empty()) return false;
 512   entered_contexts_.RemoveLast();
 513   return true;
 514 }
 515
 516
 517 Handle<Object> HandleScopeImplementer::LastEnteredContext() {
 518   if (entered_contexts_.is_empty()) return Handle<Object>::null();
 519   return entered_contexts_.last();
 520 }
 521
 522
 523 // If there's a spare block, use it for growing the current scope.
 524 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 525   internal::Object** block = (spare_ != NULL) ?
 526       spare_ :
 527       NewArray<internal::Object*>(kHandleBlockSize);
 528   spare_ = NULL;
 529   return block;
 530 }
 531
 532
 533 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 534   while (!blocks_.is_empty()) {
 535     internal::Object** block_start = blocks_.last();
 536     internal::Object** block_limit = block_start + kHandleBlockSize;
 537 #ifdef DEBUG
 538     // NoHandleAllocation may make the prev_limit to point inside the block.
 539     if (block_start <= prev_limit && prev_limit <= block_limit) break;
 540 #else
 541     if (prev_limit == block_limit) break;
 542 #endif
 543
 544     blocks_.RemoveLast();
 545 #ifdef DEBUG
 546     v8::ImplementationUtilities::ZapHandleRange(block_start, block_limit);
 547 #endif
 548     if (spare_ != NULL) {
 549       DeleteArray(spare_);
 550     }
 551     spare_ = block_start;
 552   }
 553   ASSERT((blocks_.is_empty() && prev_limit == NULL) ||
 554          (!blocks_.is_empty() && prev_limit != NULL));
 555 }
 556
 557
 558 class Testing {
 559  public:
 560   static v8::Testing::StressType stress_type() { return stress_type_; }
 561   static void set_stress_type(v8::Testing::StressType stress_type) {
 562     stress_type_ = stress_type;
 563   }
 564
 565  private:
 566   static v8::Testing::StressType stress_type_;
 567 };
 568
 569 } }  // namespace v8::internal
 570
 571 #endif  // V8_API_H_