src/api.h

   1 // Copyright 2011 the V8 project authors. All rights reserved.
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   5 //
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   7 //       notice, this list of conditions and the following disclaimer.
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  14 //       from this software without specific prior written permission.
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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>(v8::internal::Foreign::cast(obj)->address()));
 119 }
 120
 121
 122 template <typename T>
 123 static inline v8::internal::Handle<v8::internal::Object> FromCData(T obj) {
 124   STATIC_ASSERT(sizeof(T) == sizeof(v8::internal::Address));
 125   return FACTORY->NewForeign(
 126       reinterpret_cast<v8::internal::Address>(reinterpret_cast<intptr_t>(obj)));
 127 }
 128
 129
 130 class ApiFunction {
 131  public:
 132   explicit ApiFunction(v8::internal::Address addr) : addr_(addr) { }
 133   v8::internal::Address address() { return addr_; }
 134  private:
 135   v8::internal::Address addr_;
 136 };
 137
 138
 139 enum ExtensionTraversalState {
 140   UNVISITED, VISITED, INSTALLED
 141 };
 142
 143
 144 class RegisteredExtension {
 145  public:
 146   explicit RegisteredExtension(Extension* extension);
 147   static void Register(RegisteredExtension* that);
 148   Extension* extension() { return extension_; }
 149   RegisteredExtension* next() { return next_; }
 150   RegisteredExtension* next_auto() { return next_auto_; }
 151   ExtensionTraversalState state() { return state_; }
 152   void set_state(ExtensionTraversalState value) { state_ = value; }
 153   static RegisteredExtension* first_extension() { return first_extension_; }
 154  private:
 155   Extension* extension_;
 156   RegisteredExtension* next_;
 157   RegisteredExtension* next_auto_;
 158   ExtensionTraversalState state_;
 159   static RegisteredExtension* first_extension_;
 160 };
 161
 162
 163 class Utils {
 164  public:
 165   static bool ReportApiFailure(const char* location, const char* message);
 166
 167   static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
 168   static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
 169
 170   static inline Local<Context> ToLocal(
 171       v8::internal::Handle<v8::internal::Context> obj);
 172   static inline Local<Value> ToLocal(
 173       v8::internal::Handle<v8::internal::Object> obj);
 174   static inline Local<Function> ToLocal(
 175       v8::internal::Handle<v8::internal::JSFunction> obj);
 176   static inline Local<String> ToLocal(
 177       v8::internal::Handle<v8::internal::String> obj);
 178   static inline Local<RegExp> ToLocal(
 179       v8::internal::Handle<v8::internal::JSRegExp> obj);
 180   static inline Local<Object> ToLocal(
 181       v8::internal::Handle<v8::internal::JSObject> obj);
 182   static inline Local<Array> ToLocal(
 183       v8::internal::Handle<v8::internal::JSArray> obj);
 184   static inline Local<External> ToLocal(
 185       v8::internal::Handle<v8::internal::Foreign> obj);
 186   static inline Local<Message> MessageToLocal(
 187       v8::internal::Handle<v8::internal::Object> obj);
 188   static inline Local<StackTrace> StackTraceToLocal(
 189       v8::internal::Handle<v8::internal::JSArray> obj);
 190   static inline Local<StackFrame> StackFrameToLocal(
 191       v8::internal::Handle<v8::internal::JSObject> obj);
 192   static inline Local<Number> NumberToLocal(
 193       v8::internal::Handle<v8::internal::Object> obj);
 194   static inline Local<Integer> IntegerToLocal(
 195       v8::internal::Handle<v8::internal::Object> obj);
 196   static inline Local<Uint32> Uint32ToLocal(
 197       v8::internal::Handle<v8::internal::Object> obj);
 198   static inline Local<FunctionTemplate> ToLocal(
 199       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 200   static inline Local<ObjectTemplate> ToLocal(
 201       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 202   static inline Local<Signature> ToLocal(
 203       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 204   static inline Local<TypeSwitch> ToLocal(
 205       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 206
 207   static inline v8::internal::Handle<v8::internal::TemplateInfo>
 208       OpenHandle(const Template* that);
 209   static inline v8::internal::Handle<v8::internal::FunctionTemplateInfo>
 210       OpenHandle(const FunctionTemplate* that);
 211   static inline v8::internal::Handle<v8::internal::ObjectTemplateInfo>
 212       OpenHandle(const ObjectTemplate* that);
 213   static inline v8::internal::Handle<v8::internal::Object>
 214       OpenHandle(const Data* data);
 215   static inline v8::internal::Handle<v8::internal::JSRegExp>
 216       OpenHandle(const RegExp* data);
 217   static inline v8::internal::Handle<v8::internal::JSObject>
 218       OpenHandle(const v8::Object* data);
 219   static inline v8::internal::Handle<v8::internal::JSArray>
 220       OpenHandle(const v8::Array* data);
 221   static inline v8::internal::Handle<v8::internal::String>
 222       OpenHandle(const String* data);
 223   static inline v8::internal::Handle<v8::internal::Object>
 224       OpenHandle(const Script* data);
 225   static inline v8::internal::Handle<v8::internal::JSFunction>
 226       OpenHandle(const Function* data);
 227   static inline v8::internal::Handle<v8::internal::JSObject>
 228       OpenHandle(const Message* message);
 229   static inline v8::internal::Handle<v8::internal::JSArray>
 230       OpenHandle(const StackTrace* stack_trace);
 231   static inline v8::internal::Handle<v8::internal::JSObject>
 232       OpenHandle(const StackFrame* stack_frame);
 233   static inline v8::internal::Handle<v8::internal::Context>
 234       OpenHandle(const v8::Context* context);
 235   static inline v8::internal::Handle<v8::internal::SignatureInfo>
 236       OpenHandle(const v8::Signature* sig);
 237   static inline v8::internal::Handle<v8::internal::TypeSwitchInfo>
 238       OpenHandle(const v8::TypeSwitch* that);
 239   static inline v8::internal::Handle<v8::internal::Foreign>
 240       OpenHandle(const v8::External* that);
 241 };
 242
 243
 244 template <class T>
 245 static inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 246   return reinterpret_cast<T*>(obj.location());
 247 }
 248
 249
 250 template <class T>
 251 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 252     v8::HandleScope* scope) {
 253   v8::internal::Handle<T> handle;
 254   if (!is_null()) {
 255     handle = *this;
 256   }
 257   return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)));
 258 }
 259
 260
 261 // Implementations of ToLocal
 262
 263 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 264   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 265     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
 266     return Local<To>(reinterpret_cast<To*>(obj.location()));                \
 267   }
 268
 269 MAKE_TO_LOCAL(ToLocal, Context, Context)
 270 MAKE_TO_LOCAL(ToLocal, Object, Value)
 271 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 272 MAKE_TO_LOCAL(ToLocal, String, String)
 273 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 274 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 275 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 276 MAKE_TO_LOCAL(ToLocal, Foreign, External)
 277 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
 278 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
 279 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
 280 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 281 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 282 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 283 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 284 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 285 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 286 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 287
 288 #undef MAKE_TO_LOCAL
 289
 290
 291 // Implementations of OpenHandle
 292
 293 #define MAKE_OPEN_HANDLE(From, To) \
 294   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(\
 295     const v8::From* that) { \
 296     return v8::internal::Handle<v8::internal::To>( \
 297         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 298   }
 299
 300 MAKE_OPEN_HANDLE(Template, TemplateInfo)
 301 MAKE_OPEN_HANDLE(FunctionTemplate, FunctionTemplateInfo)
 302 MAKE_OPEN_HANDLE(ObjectTemplate, ObjectTemplateInfo)
 303 MAKE_OPEN_HANDLE(Signature, SignatureInfo)
 304 MAKE_OPEN_HANDLE(TypeSwitch, TypeSwitchInfo)
 305 MAKE_OPEN_HANDLE(Data, Object)
 306 MAKE_OPEN_HANDLE(RegExp, JSRegExp)
 307 MAKE_OPEN_HANDLE(Object, JSObject)
 308 MAKE_OPEN_HANDLE(Array, JSArray)
 309 MAKE_OPEN_HANDLE(String, String)
 310 MAKE_OPEN_HANDLE(Script, Object)
 311 MAKE_OPEN_HANDLE(Function, JSFunction)
 312 MAKE_OPEN_HANDLE(Message, JSObject)
 313 MAKE_OPEN_HANDLE(Context, Context)
 314 MAKE_OPEN_HANDLE(External, Foreign)
 315 MAKE_OPEN_HANDLE(StackTrace, JSArray)
 316 MAKE_OPEN_HANDLE(StackFrame, JSObject)
 317
 318 #undef MAKE_OPEN_HANDLE
 319
 320
 321 namespace internal {
 322
 323 // Tracks string usage to help make better decisions when
 324 // externalizing strings.
 325 //
 326 // Implementation note: internally this class only tracks fresh
 327 // strings and keeps a single use counter for them.
 328 class StringTracker {
 329  public:
 330   // Records that the given string's characters were copied to some
 331   // external buffer. If this happens often we should honor
 332   // externalization requests for the string.
 333   void RecordWrite(Handle<String> string) {
 334     Address address = reinterpret_cast<Address>(*string);
 335     Address top = isolate_->heap()->NewSpaceTop();
 336     if (IsFreshString(address, top)) {
 337       IncrementUseCount(top);
 338     }
 339   }
 340
 341   // Estimates freshness and use frequency of the given string based
 342   // on how close it is to the new space top and the recorded usage
 343   // history.
 344   inline bool IsFreshUnusedString(Handle<String> string) {
 345     Address address = reinterpret_cast<Address>(*string);
 346     Address top = isolate_->heap()->NewSpaceTop();
 347     return IsFreshString(address, top) && IsUseCountLow(top);
 348   }
 349
 350  private:
 351   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 352
 353   static inline bool IsFreshString(Address string, Address top) {
 354     return top - kFreshnessLimit <= string && string <= top;
 355   }
 356
 357   inline bool IsUseCountLow(Address top) {
 358     if (last_top_ != top) return true;
 359     return use_count_ < kUseLimit;
 360   }
 361
 362   inline void IncrementUseCount(Address top) {
 363     if (last_top_ != top) {
 364       use_count_ = 0;
 365       last_top_ = top;
 366     }
 367     ++use_count_;
 368   }
 369
 370   // Single use counter shared by all fresh strings.
 371   int use_count_;
 372
 373   // Last new space top when the use count above was valid.
 374   Address last_top_;
 375
 376   Isolate* isolate_;
 377
 378   // How close to the new space top a fresh string has to be.
 379   static const int kFreshnessLimit = 1024;
 380
 381   // The number of uses required to consider a string useful.
 382   static const int kUseLimit = 32;
 383
 384   friend class Isolate;
 385
 386   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 387 };
 388
 389
 390 // This class is here in order to be able to declare it a friend of
 391 // HandleScope.  Moving these methods to be members of HandleScope would be
 392 // neat in some ways, but it would expose internal implementation details in
 393 // our public header file, which is undesirable.
 394 //
 395 // An isolate has a single instance of this class to hold the current thread's
 396 // data. In multithreaded V8 programs this data is copied in and out of storage
 397 // so that the currently executing thread always has its own copy of this
 398 // data.
 399 class HandleScopeImplementer {
 400  public:
 401
 402   explicit HandleScopeImplementer(Isolate* isolate)
 403       : isolate_(isolate),
 404         blocks_(0),
 405         entered_contexts_(0),
 406         saved_contexts_(0),
 407         spare_(NULL),
 408         ignore_out_of_memory_(false),
 409         call_depth_(0) { }
 410
 411   // Threading support for handle data.
 412   static int ArchiveSpacePerThread();
 413   char* RestoreThread(char* from);
 414   char* ArchiveThread(char* to);
 415   void FreeThreadResources();
 416
 417   // Garbage collection support.
 418   void Iterate(v8::internal::ObjectVisitor* v);
 419   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 420
 421
 422   inline internal::Object** GetSpareOrNewBlock();
 423   inline void DeleteExtensions(internal::Object** prev_limit);
 424
 425   inline void IncrementCallDepth() {call_depth_++;}
 426   inline void DecrementCallDepth() {call_depth_--;}
 427   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 428
 429   inline void EnterContext(Handle<Object> context);
 430   inline bool LeaveLastContext();
 431
 432   // Returns the last entered context or an empty handle if no
 433   // contexts have been entered.
 434   inline Handle<Object> LastEnteredContext();
 435
 436   inline void SaveContext(Context* context);
 437   inline Context* RestoreContext();
 438   inline bool HasSavedContexts();
 439
 440   inline List<internal::Object**>* blocks() { return &blocks_; }
 441   inline bool ignore_out_of_memory() { return ignore_out_of_memory_; }
 442   inline void set_ignore_out_of_memory(bool value) {
 443     ignore_out_of_memory_ = value;
 444   }
 445
 446  private:
 447   void ResetAfterArchive() {
 448     blocks_.Initialize(0);
 449     entered_contexts_.Initialize(0);
 450     saved_contexts_.Initialize(0);
 451     spare_ = NULL;
 452     ignore_out_of_memory_ = false;
 453     call_depth_ = 0;
 454   }
 455
 456   void Free() {
 457     ASSERT(blocks_.length() == 0);
 458     ASSERT(entered_contexts_.length() == 0);
 459     ASSERT(saved_contexts_.length() == 0);
 460     blocks_.Free();
 461     entered_contexts_.Free();
 462     saved_contexts_.Free();
 463     if (spare_ != NULL) {
 464       DeleteArray(spare_);
 465       spare_ = NULL;
 466     }
 467     ASSERT(call_depth_ == 0);
 468   }
 469
 470   Isolate* isolate_;
 471   List<internal::Object**> blocks_;
 472   // Used as a stack to keep track of entered contexts.
 473   List<Handle<Object> > entered_contexts_;
 474   // Used as a stack to keep track of saved contexts.
 475   List<Context*> saved_contexts_;
 476   Object** spare_;
 477   bool ignore_out_of_memory_;
 478   int call_depth_;
 479   // This is only used for threading support.
 480   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
 481
 482   void IterateThis(ObjectVisitor* v);
 483   char* RestoreThreadHelper(char* from);
 484   char* ArchiveThreadHelper(char* to);
 485
 486   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 487 };
 488
 489
 490 static const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 491
 492
 493 void HandleScopeImplementer::SaveContext(Context* context) {
 494   saved_contexts_.Add(context);
 495 }
 496
 497
 498 Context* HandleScopeImplementer::RestoreContext() {
 499   return saved_contexts_.RemoveLast();
 500 }
 501
 502
 503 bool HandleScopeImplementer::HasSavedContexts() {
 504   return !saved_contexts_.is_empty();
 505 }
 506
 507
 508 void HandleScopeImplementer::EnterContext(Handle<Object> context) {
 509   entered_contexts_.Add(context);
 510 }
 511
 512
 513 bool HandleScopeImplementer::LeaveLastContext() {
 514   if (entered_contexts_.is_empty()) return false;
 515   entered_contexts_.RemoveLast();
 516   return true;
 517 }
 518
 519
 520 Handle<Object> HandleScopeImplementer::LastEnteredContext() {
 521   if (entered_contexts_.is_empty()) return Handle<Object>::null();
 522   return entered_contexts_.last();
 523 }
 524
 525
 526 // If there's a spare block, use it for growing the current scope.
 527 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 528   internal::Object** block = (spare_ != NULL) ?
 529       spare_ :
 530       NewArray<internal::Object*>(kHandleBlockSize);
 531   spare_ = NULL;
 532   return block;
 533 }
 534
 535
 536 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 537   while (!blocks_.is_empty()) {
 538     internal::Object** block_start = blocks_.last();
 539     internal::Object** block_limit = block_start + kHandleBlockSize;
 540 #ifdef DEBUG
 541     // NoHandleAllocation may make the prev_limit to point inside the block.
 542     if (block_start <= prev_limit && prev_limit <= block_limit) break;
 543 #else
 544     if (prev_limit == block_limit) break;
 545 #endif
 546
 547     blocks_.RemoveLast();
 548 #ifdef DEBUG
 549     v8::ImplementationUtilities::ZapHandleRange(block_start, block_limit);
 550 #endif
 551     if (spare_ != NULL) {
 552       DeleteArray(spare_);
 553     }
 554     spare_ = block_start;
 555   }
 556   ASSERT((blocks_.is_empty() && prev_limit == NULL) ||
 557          (!blocks_.is_empty() && prev_limit != NULL));
 558 }
 559
 560
 561 class Testing {
 562  public:
 563   static v8::Testing::StressType stress_type() { return stress_type_; }
 564   static void set_stress_type(v8::Testing::StressType stress_type) {
 565     stress_type_ = stress_type;
 566   }
 567
 568  private:
 569   static v8::Testing::StressType stress_type_;
 570 };
 571
 572 } }  // namespace v8::internal
 573
 574 #endif  // V8_API_H_