src/api.h

   1 // Copyright 2011 the V8 project authors. All rights reserved.
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   4 // met:
   5 //
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   7 //       notice, this list of conditions and the following disclaimer.
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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
 141 class RegisteredExtension {
 142  public:
 143   explicit RegisteredExtension(Extension* extension);
 144   static void Register(RegisteredExtension* that);
 145   Extension* extension() { return extension_; }
 146   RegisteredExtension* next() { return next_; }
 147   RegisteredExtension* next_auto() { return next_auto_; }
 148   static RegisteredExtension* first_extension() { return first_extension_; }
 149  private:
 150   Extension* extension_;
 151   RegisteredExtension* next_;
 152   RegisteredExtension* next_auto_;
 153   static RegisteredExtension* first_extension_;
 154 };
 155
 156
 157 class Utils {
 158  public:
 159   static bool ReportApiFailure(const char* location, const char* message);
 160
 161   static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
 162   static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
 163
 164   static inline Local<Context> ToLocal(
 165       v8::internal::Handle<v8::internal::Context> obj);
 166   static inline Local<Value> ToLocal(
 167       v8::internal::Handle<v8::internal::Object> obj);
 168   static inline Local<Function> ToLocal(
 169       v8::internal::Handle<v8::internal::JSFunction> obj);
 170   static inline Local<String> ToLocal(
 171       v8::internal::Handle<v8::internal::String> obj);
 172   static inline Local<RegExp> ToLocal(
 173       v8::internal::Handle<v8::internal::JSRegExp> obj);
 174   static inline Local<Object> ToLocal(
 175       v8::internal::Handle<v8::internal::JSObject> obj);
 176   static inline Local<Array> ToLocal(
 177       v8::internal::Handle<v8::internal::JSArray> obj);
 178   static inline Local<External> ToLocal(
 179       v8::internal::Handle<v8::internal::Foreign> obj);
 180   static inline Local<Message> MessageToLocal(
 181       v8::internal::Handle<v8::internal::Object> obj);
 182   static inline Local<StackTrace> StackTraceToLocal(
 183       v8::internal::Handle<v8::internal::JSArray> obj);
 184   static inline Local<StackFrame> StackFrameToLocal(
 185       v8::internal::Handle<v8::internal::JSObject> obj);
 186   static inline Local<Number> NumberToLocal(
 187       v8::internal::Handle<v8::internal::Object> obj);
 188   static inline Local<Integer> IntegerToLocal(
 189       v8::internal::Handle<v8::internal::Object> obj);
 190   static inline Local<Uint32> Uint32ToLocal(
 191       v8::internal::Handle<v8::internal::Object> obj);
 192   static inline Local<FunctionTemplate> ToLocal(
 193       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 194   static inline Local<ObjectTemplate> ToLocal(
 195       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 196   static inline Local<Signature> ToLocal(
 197       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 198   static inline Local<TypeSwitch> ToLocal(
 199       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 200
 201   static inline v8::internal::Handle<v8::internal::TemplateInfo>
 202       OpenHandle(const Template* that);
 203   static inline v8::internal::Handle<v8::internal::FunctionTemplateInfo>
 204       OpenHandle(const FunctionTemplate* that);
 205   static inline v8::internal::Handle<v8::internal::ObjectTemplateInfo>
 206       OpenHandle(const ObjectTemplate* that);
 207   static inline v8::internal::Handle<v8::internal::Object>
 208       OpenHandle(const Data* data);
 209   static inline v8::internal::Handle<v8::internal::JSRegExp>
 210       OpenHandle(const RegExp* data);
 211   static inline v8::internal::Handle<v8::internal::JSObject>
 212       OpenHandle(const v8::Object* data);
 213   static inline v8::internal::Handle<v8::internal::JSArray>
 214       OpenHandle(const v8::Array* data);
 215   static inline v8::internal::Handle<v8::internal::String>
 216       OpenHandle(const String* data);
 217   static inline v8::internal::Handle<v8::internal::Object>
 218       OpenHandle(const Script* data);
 219   static inline v8::internal::Handle<v8::internal::JSFunction>
 220       OpenHandle(const Function* data);
 221   static inline v8::internal::Handle<v8::internal::JSObject>
 222       OpenHandle(const Message* message);
 223   static inline v8::internal::Handle<v8::internal::JSArray>
 224       OpenHandle(const StackTrace* stack_trace);
 225   static inline v8::internal::Handle<v8::internal::JSObject>
 226       OpenHandle(const StackFrame* stack_frame);
 227   static inline v8::internal::Handle<v8::internal::Context>
 228       OpenHandle(const v8::Context* context);
 229   static inline v8::internal::Handle<v8::internal::SignatureInfo>
 230       OpenHandle(const v8::Signature* sig);
 231   static inline v8::internal::Handle<v8::internal::TypeSwitchInfo>
 232       OpenHandle(const v8::TypeSwitch* that);
 233   static inline v8::internal::Handle<v8::internal::Foreign>
 234       OpenHandle(const v8::External* that);
 235 };
 236
 237
 238 template <class T>
 239 static inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 240   return reinterpret_cast<T*>(obj.location());
 241 }
 242
 243
 244 template <class T>
 245 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 246     v8::HandleScope* scope) {
 247   v8::internal::Handle<T> handle;
 248   if (!is_null()) {
 249     handle = *this;
 250   }
 251   return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)));
 252 }
 253
 254
 255 // Implementations of ToLocal
 256
 257 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 258   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 259     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
 260     return Local<To>(reinterpret_cast<To*>(obj.location()));                \
 261   }
 262
 263 MAKE_TO_LOCAL(ToLocal, Context, Context)
 264 MAKE_TO_LOCAL(ToLocal, Object, Value)
 265 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 266 MAKE_TO_LOCAL(ToLocal, String, String)
 267 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 268 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 269 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 270 MAKE_TO_LOCAL(ToLocal, Foreign, External)
 271 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
 272 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
 273 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
 274 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 275 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 276 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 277 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 278 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 279 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 280 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 281
 282 #undef MAKE_TO_LOCAL
 283
 284
 285 // Implementations of OpenHandle
 286
 287 #define MAKE_OPEN_HANDLE(From, To) \
 288   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(\
 289     const v8::From* that) { \
 290     return v8::internal::Handle<v8::internal::To>( \
 291         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 292   }
 293
 294 MAKE_OPEN_HANDLE(Template, TemplateInfo)
 295 MAKE_OPEN_HANDLE(FunctionTemplate, FunctionTemplateInfo)
 296 MAKE_OPEN_HANDLE(ObjectTemplate, ObjectTemplateInfo)
 297 MAKE_OPEN_HANDLE(Signature, SignatureInfo)
 298 MAKE_OPEN_HANDLE(TypeSwitch, TypeSwitchInfo)
 299 MAKE_OPEN_HANDLE(Data, Object)
 300 MAKE_OPEN_HANDLE(RegExp, JSRegExp)
 301 MAKE_OPEN_HANDLE(Object, JSObject)
 302 MAKE_OPEN_HANDLE(Array, JSArray)
 303 MAKE_OPEN_HANDLE(String, String)
 304 MAKE_OPEN_HANDLE(Script, Object)
 305 MAKE_OPEN_HANDLE(Function, JSFunction)
 306 MAKE_OPEN_HANDLE(Message, JSObject)
 307 MAKE_OPEN_HANDLE(Context, Context)
 308 MAKE_OPEN_HANDLE(External, Foreign)
 309 MAKE_OPEN_HANDLE(StackTrace, JSArray)
 310 MAKE_OPEN_HANDLE(StackFrame, JSObject)
 311
 312 #undef MAKE_OPEN_HANDLE
 313
 314
 315 namespace internal {
 316
 317 // Tracks string usage to help make better decisions when
 318 // externalizing strings.
 319 //
 320 // Implementation note: internally this class only tracks fresh
 321 // strings and keeps a single use counter for them.
 322 class StringTracker {
 323  public:
 324   // Records that the given string's characters were copied to some
 325   // external buffer. If this happens often we should honor
 326   // externalization requests for the string.
 327   void RecordWrite(Handle<String> string) {
 328     Address address = reinterpret_cast<Address>(*string);
 329     Address top = isolate_->heap()->NewSpaceTop();
 330     if (IsFreshString(address, top)) {
 331       IncrementUseCount(top);
 332     }
 333   }
 334
 335   // Estimates freshness and use frequency of the given string based
 336   // on how close it is to the new space top and the recorded usage
 337   // history.
 338   inline bool IsFreshUnusedString(Handle<String> string) {
 339     Address address = reinterpret_cast<Address>(*string);
 340     Address top = isolate_->heap()->NewSpaceTop();
 341     return IsFreshString(address, top) && IsUseCountLow(top);
 342   }
 343
 344  private:
 345   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 346
 347   static inline bool IsFreshString(Address string, Address top) {
 348     return top - kFreshnessLimit <= string && string <= top;
 349   }
 350
 351   inline bool IsUseCountLow(Address top) {
 352     if (last_top_ != top) return true;
 353     return use_count_ < kUseLimit;
 354   }
 355
 356   inline void IncrementUseCount(Address top) {
 357     if (last_top_ != top) {
 358       use_count_ = 0;
 359       last_top_ = top;
 360     }
 361     ++use_count_;
 362   }
 363
 364   // Single use counter shared by all fresh strings.
 365   int use_count_;
 366
 367   // Last new space top when the use count above was valid.
 368   Address last_top_;
 369
 370   Isolate* isolate_;
 371
 372   // How close to the new space top a fresh string has to be.
 373   static const int kFreshnessLimit = 1024;
 374
 375   // The number of uses required to consider a string useful.
 376   static const int kUseLimit = 32;
 377
 378   friend class Isolate;
 379
 380   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 381 };
 382
 383
 384 // This class is here in order to be able to declare it a friend of
 385 // HandleScope.  Moving these methods to be members of HandleScope would be
 386 // neat in some ways, but it would expose internal implementation details in
 387 // our public header file, which is undesirable.
 388 //
 389 // An isolate has a single instance of this class to hold the current thread's
 390 // data. In multithreaded V8 programs this data is copied in and out of storage
 391 // so that the currently executing thread always has its own copy of this
 392 // data.
 393 class HandleScopeImplementer {
 394  public:
 395   explicit HandleScopeImplementer(Isolate* isolate)
 396       : isolate_(isolate),
 397         blocks_(0),
 398         entered_contexts_(0),
 399         saved_contexts_(0),
 400         spare_(NULL),
 401         call_depth_(0) { }
 402
 403   ~HandleScopeImplementer() {
 404     DeleteArray(spare_);
 405   }
 406
 407   // Threading support for handle data.
 408   static int ArchiveSpacePerThread();
 409   char* RestoreThread(char* from);
 410   char* ArchiveThread(char* to);
 411   void FreeThreadResources();
 412
 413   // Garbage collection support.
 414   void Iterate(v8::internal::ObjectVisitor* v);
 415   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 416
 417
 418   inline internal::Object** GetSpareOrNewBlock();
 419   inline void DeleteExtensions(internal::Object** prev_limit);
 420
 421   inline void IncrementCallDepth() {call_depth_++;}
 422   inline void DecrementCallDepth() {call_depth_--;}
 423   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 424
 425   inline void EnterContext(Handle<Object> context);
 426   inline bool LeaveLastContext();
 427
 428   // Returns the last entered context or an empty handle if no
 429   // contexts have been entered.
 430   inline Handle<Object> LastEnteredContext();
 431
 432   inline void SaveContext(Context* context);
 433   inline Context* RestoreContext();
 434   inline bool HasSavedContexts();
 435
 436   inline List<internal::Object**>* blocks() { return &blocks_; }
 437
 438  private:
 439   void ResetAfterArchive() {
 440     blocks_.Initialize(0);
 441     entered_contexts_.Initialize(0);
 442     saved_contexts_.Initialize(0);
 443     spare_ = NULL;
 444     call_depth_ = 0;
 445   }
 446
 447   void Free() {
 448     ASSERT(blocks_.length() == 0);
 449     ASSERT(entered_contexts_.length() == 0);
 450     ASSERT(saved_contexts_.length() == 0);
 451     blocks_.Free();
 452     entered_contexts_.Free();
 453     saved_contexts_.Free();
 454     if (spare_ != NULL) {
 455       DeleteArray(spare_);
 456       spare_ = NULL;
 457     }
 458     ASSERT(call_depth_ == 0);
 459   }
 460
 461   Isolate* isolate_;
 462   List<internal::Object**> blocks_;
 463   // Used as a stack to keep track of entered contexts.
 464   List<Handle<Object> > entered_contexts_;
 465   // Used as a stack to keep track of saved contexts.
 466   List<Context*> saved_contexts_;
 467   Object** spare_;
 468   int call_depth_;
 469   // This is only used for threading support.
 470   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
 471
 472   void IterateThis(ObjectVisitor* v);
 473   char* RestoreThreadHelper(char* from);
 474   char* ArchiveThreadHelper(char* to);
 475
 476   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 477 };
 478
 479
 480 static const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 481
 482
 483 void HandleScopeImplementer::SaveContext(Context* context) {
 484   saved_contexts_.Add(context);
 485 }
 486
 487
 488 Context* HandleScopeImplementer::RestoreContext() {
 489   return saved_contexts_.RemoveLast();
 490 }
 491
 492
 493 bool HandleScopeImplementer::HasSavedContexts() {
 494   return !saved_contexts_.is_empty();
 495 }
 496
 497
 498 void HandleScopeImplementer::EnterContext(Handle<Object> context) {
 499   entered_contexts_.Add(context);
 500 }
 501
 502
 503 bool HandleScopeImplementer::LeaveLastContext() {
 504   if (entered_contexts_.is_empty()) return false;
 505   entered_contexts_.RemoveLast();
 506   return true;
 507 }
 508
 509
 510 Handle<Object> HandleScopeImplementer::LastEnteredContext() {
 511   if (entered_contexts_.is_empty()) return Handle<Object>::null();
 512   return entered_contexts_.last();
 513 }
 514
 515
 516 // If there's a spare block, use it for growing the current scope.
 517 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 518   internal::Object** block = (spare_ != NULL) ?
 519       spare_ :
 520       NewArray<internal::Object*>(kHandleBlockSize);
 521   spare_ = NULL;
 522   return block;
 523 }
 524
 525
 526 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 527   while (!blocks_.is_empty()) {
 528     internal::Object** block_start = blocks_.last();
 529     internal::Object** block_limit = block_start + kHandleBlockSize;
 530 #ifdef DEBUG
 531     // NoHandleAllocation may make the prev_limit to point inside the block.
 532     if (block_start <= prev_limit && prev_limit <= block_limit) break;
 533 #else
 534     if (prev_limit == block_limit) break;
 535 #endif
 536
 537     blocks_.RemoveLast();
 538 #ifdef DEBUG
 539     v8::ImplementationUtilities::ZapHandleRange(block_start, block_limit);
 540 #endif
 541     if (spare_ != NULL) {
 542       DeleteArray(spare_);
 543     }
 544     spare_ = block_start;
 545   }
 546   ASSERT((blocks_.is_empty() && prev_limit == NULL) ||
 547          (!blocks_.is_empty() && prev_limit != NULL));
 548 }
 549
 550
 551 class Testing {
 552  public:
 553   static v8::Testing::StressType stress_type() { return stress_type_; }
 554   static void set_stress_type(v8::Testing::StressType stress_type) {
 555     stress_type_ = stress_type;
 556   }
 557
 558  private:
 559   static v8::Testing::StressType stress_type_;
 560 };
 561
 562 } }  // namespace v8::internal
 563
 564 #endif  // V8_API_H_