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