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 #define OPEN_HANDLE_LIST(V)                    \
 163   V(Template, TemplateInfo)                    \
 164   V(FunctionTemplate, FunctionTemplateInfo)    \
 165   V(ObjectTemplate, ObjectTemplateInfo)        \
 166   V(Signature, SignatureInfo)                  \
 167   V(AccessorSignature, FunctionTemplateInfo)   \
 168   V(TypeSwitch, TypeSwitchInfo)                \
 169   V(Data, Object)                              \
 170   V(RegExp, JSRegExp)                          \
 171   V(Object, JSObject)                          \
 172   V(Array, JSArray)                            \
 173   V(String, String)                            \
 174   V(Script, Object)                            \
 175   V(Function, JSFunction)                      \
 176   V(Message, JSObject)                         \
 177   V(Context, Context)                          \
 178   V(External, Foreign)                         \
 179   V(StackTrace, JSArray)                       \
 180   V(StackFrame, JSObject)
 181
 182
 183 class Utils {
 184  public:
 185   static bool ReportApiFailure(const char* location, const char* message);
 186
 187   static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
 188   static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
 189
 190   static inline Local<Context> ToLocal(
 191       v8::internal::Handle<v8::internal::Context> obj);
 192   static inline Local<Value> ToLocal(
 193       v8::internal::Handle<v8::internal::Object> obj);
 194   static inline Local<Function> ToLocal(
 195       v8::internal::Handle<v8::internal::JSFunction> obj);
 196   static inline Local<String> ToLocal(
 197       v8::internal::Handle<v8::internal::String> obj);
 198   static inline Local<RegExp> ToLocal(
 199       v8::internal::Handle<v8::internal::JSRegExp> obj);
 200   static inline Local<Object> ToLocal(
 201       v8::internal::Handle<v8::internal::JSObject> obj);
 202   static inline Local<Array> ToLocal(
 203       v8::internal::Handle<v8::internal::JSArray> obj);
 204   static inline Local<Message> MessageToLocal(
 205       v8::internal::Handle<v8::internal::Object> obj);
 206   static inline Local<StackTrace> StackTraceToLocal(
 207       v8::internal::Handle<v8::internal::JSArray> obj);
 208   static inline Local<StackFrame> StackFrameToLocal(
 209       v8::internal::Handle<v8::internal::JSObject> obj);
 210   static inline Local<Number> NumberToLocal(
 211       v8::internal::Handle<v8::internal::Object> obj);
 212   static inline Local<Integer> IntegerToLocal(
 213       v8::internal::Handle<v8::internal::Object> obj);
 214   static inline Local<Uint32> Uint32ToLocal(
 215       v8::internal::Handle<v8::internal::Object> obj);
 216   static inline Local<FunctionTemplate> ToLocal(
 217       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 218   static inline Local<ObjectTemplate> ToLocal(
 219       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 220   static inline Local<Signature> ToLocal(
 221       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 222   static inline Local<AccessorSignature> AccessorSignatureToLocal(
 223       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 224   static inline Local<TypeSwitch> ToLocal(
 225       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 226   static inline Local<External> ExternalToLocal(
 227       v8::internal::Handle<v8::internal::JSObject> obj);
 228
 229 #define DECLARE_OPEN_HANDLE(From, To) \
 230   static inline v8::internal::Handle<v8::internal::To> \
 231       OpenHandle(const From* that, bool allow_empty_handle = false);
 232
 233 OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 234
 235 #undef DECLARE_OPEN_HANDLE
 236 };
 237
 238
 239 template <class T>
 240 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 241   return reinterpret_cast<T*>(obj.location());
 242 }
 243
 244
 245 template <class T>
 246 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 247     v8::HandleScope* scope) {
 248   v8::internal::Handle<T> handle;
 249   if (!is_null()) {
 250     handle = *this;
 251   }
 252   return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)), true);
 253 }
 254
 255
 256 // Implementations of ToLocal
 257
 258 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 259   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 260     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
 261     return Local<To>(reinterpret_cast<To*>(obj.location()));                \
 262   }
 263
 264 MAKE_TO_LOCAL(ToLocal, Context, Context)
 265 MAKE_TO_LOCAL(ToLocal, Object, Value)
 266 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 267 MAKE_TO_LOCAL(ToLocal, String, String)
 268 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 269 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 270 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 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(AccessorSignatureToLocal, FunctionTemplateInfo, AccessorSignature)
 275 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 276 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 277 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 278 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 279 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 280 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 281 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 282 MAKE_TO_LOCAL(ExternalToLocal, JSObject, External)
 283
 284 #undef MAKE_TO_LOCAL
 285
 286
 287 // Implementations of OpenHandle
 288
 289 #define MAKE_OPEN_HANDLE(From, To)                                          \
 290   v8::internal::Handle<v8::internal::To> Utils::OpenHandle(                 \
 291     const v8::From* that, bool allow_empty_handle) {                        \
 292     EXTRA_CHECK(allow_empty_handle || that != NULL);                        \
 293     return v8::internal::Handle<v8::internal::To>(                          \
 294         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 295   }
 296
 297 OPEN_HANDLE_LIST(MAKE_OPEN_HANDLE)
 298
 299 #undef MAKE_OPEN_HANDLE
 300 #undef OPEN_HANDLE_LIST
 301
 302
 303 namespace internal {
 304
 305 // Tracks string usage to help make better decisions when
 306 // externalizing strings.
 307 //
 308 // Implementation note: internally this class only tracks fresh
 309 // strings and keeps a single use counter for them.
 310 class StringTracker {
 311  public:
 312   // Records that the given string's characters were copied to some
 313   // external buffer. If this happens often we should honor
 314   // externalization requests for the string.
 315   void RecordWrite(Handle<String> string) {
 316     Address address = reinterpret_cast<Address>(*string);
 317     Address top = isolate_->heap()->NewSpaceTop();
 318     if (IsFreshString(address, top)) {
 319       IncrementUseCount(top);
 320     }
 321   }
 322
 323   // Estimates freshness and use frequency of the given string based
 324   // on how close it is to the new space top and the recorded usage
 325   // history.
 326   inline bool IsFreshUnusedString(Handle<String> string) {
 327     Address address = reinterpret_cast<Address>(*string);
 328     Address top = isolate_->heap()->NewSpaceTop();
 329     return IsFreshString(address, top) && IsUseCountLow(top);
 330   }
 331
 332  private:
 333   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 334
 335   static inline bool IsFreshString(Address string, Address top) {
 336     return top - kFreshnessLimit <= string && string <= top;
 337   }
 338
 339   inline bool IsUseCountLow(Address top) {
 340     if (last_top_ != top) return true;
 341     return use_count_ < kUseLimit;
 342   }
 343
 344   inline void IncrementUseCount(Address top) {
 345     if (last_top_ != top) {
 346       use_count_ = 0;
 347       last_top_ = top;
 348     }
 349     ++use_count_;
 350   }
 351
 352   // Single use counter shared by all fresh strings.
 353   int use_count_;
 354
 355   // Last new space top when the use count above was valid.
 356   Address last_top_;
 357
 358   Isolate* isolate_;
 359
 360   // How close to the new space top a fresh string has to be.
 361   static const int kFreshnessLimit = 1024;
 362
 363   // The number of uses required to consider a string useful.
 364   static const int kUseLimit = 32;
 365
 366   friend class Isolate;
 367
 368   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 369 };
 370
 371
 372 class DeferredHandles {
 373  public:
 374   ~DeferredHandles();
 375
 376  private:
 377   DeferredHandles(Object** first_block_limit, Isolate* isolate)
 378       : next_(NULL),
 379         previous_(NULL),
 380         first_block_limit_(first_block_limit),
 381         isolate_(isolate) {
 382     isolate->LinkDeferredHandles(this);
 383   }
 384
 385   void Iterate(ObjectVisitor* v);
 386
 387   List<Object**> blocks_;
 388   DeferredHandles* next_;
 389   DeferredHandles* previous_;
 390   Object** first_block_limit_;
 391   Isolate* isolate_;
 392
 393   friend class HandleScopeImplementer;
 394   friend class Isolate;
 395 };
 396
 397
 398 // This class is here in order to be able to declare it a friend of
 399 // HandleScope.  Moving these methods to be members of HandleScope would be
 400 // neat in some ways, but it would expose internal implementation details in
 401 // our public header file, which is undesirable.
 402 //
 403 // An isolate has a single instance of this class to hold the current thread's
 404 // data. In multithreaded V8 programs this data is copied in and out of storage
 405 // so that the currently executing thread always has its own copy of this
 406 // data.
 407 class HandleScopeImplementer {
 408  public:
 409   explicit HandleScopeImplementer(Isolate* isolate)
 410       : isolate_(isolate),
 411         blocks_(0),
 412         entered_contexts_(0),
 413         saved_contexts_(0),
 414         spare_(NULL),
 415         call_depth_(0),
 416         last_handle_before_deferred_block_(NULL) { }
 417
 418   ~HandleScopeImplementer() {
 419     DeleteArray(spare_);
 420   }
 421
 422   // Threading support for handle data.
 423   static int ArchiveSpacePerThread();
 424   char* RestoreThread(char* from);
 425   char* ArchiveThread(char* to);
 426   void FreeThreadResources();
 427
 428   // Garbage collection support.
 429   void Iterate(v8::internal::ObjectVisitor* v);
 430   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 431
 432
 433   inline internal::Object** GetSpareOrNewBlock();
 434   inline void DeleteExtensions(internal::Object** prev_limit);
 435
 436   inline void IncrementCallDepth() {call_depth_++;}
 437   inline void DecrementCallDepth() {call_depth_--;}
 438   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 439
 440   inline void EnterContext(Handle<Object> context);
 441   inline bool LeaveLastContext();
 442
 443   // Returns the last entered context or an empty handle if no
 444   // contexts have been entered.
 445   inline Handle<Object> LastEnteredContext();
 446
 447   inline void SaveContext(Context* context);
 448   inline Context* RestoreContext();
 449   inline bool HasSavedContexts();
 450
 451   inline List<internal::Object**>* blocks() { return &blocks_; }
 452   Isolate* isolate() const { return isolate_; }
 453
 454   void ReturnBlock(Object** block) {
 455     ASSERT(block != NULL);
 456     if (spare_ != NULL) DeleteArray(spare_);
 457     spare_ = block;
 458   }
 459
 460  private:
 461   void ResetAfterArchive() {
 462     blocks_.Initialize(0);
 463     entered_contexts_.Initialize(0);
 464     saved_contexts_.Initialize(0);
 465     spare_ = NULL;
 466     last_handle_before_deferred_block_ = NULL;
 467     call_depth_ = 0;
 468   }
 469
 470   void Free() {
 471     ASSERT(blocks_.length() == 0);
 472     ASSERT(entered_contexts_.length() == 0);
 473     ASSERT(saved_contexts_.length() == 0);
 474     blocks_.Free();
 475     entered_contexts_.Free();
 476     saved_contexts_.Free();
 477     if (spare_ != NULL) {
 478       DeleteArray(spare_);
 479       spare_ = NULL;
 480     }
 481     ASSERT(call_depth_ == 0);
 482   }
 483
 484   void BeginDeferredScope();
 485   DeferredHandles* Detach(Object** prev_limit);
 486
 487   Isolate* isolate_;
 488   List<internal::Object**> blocks_;
 489   // Used as a stack to keep track of entered contexts.
 490   List<Handle<Object> > entered_contexts_;
 491   // Used as a stack to keep track of saved contexts.
 492   List<Context*> saved_contexts_;
 493   Object** spare_;
 494   int call_depth_;
 495   Object** last_handle_before_deferred_block_;
 496   // This is only used for threading support.
 497   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
 498
 499   void IterateThis(ObjectVisitor* v);
 500   char* RestoreThreadHelper(char* from);
 501   char* ArchiveThreadHelper(char* to);
 502
 503   friend class DeferredHandles;
 504   friend class DeferredHandleScope;
 505
 506   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 507 };
 508
 509
 510 const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 511
 512
 513 void HandleScopeImplementer::SaveContext(Context* context) {
 514   saved_contexts_.Add(context);
 515 }
 516
 517
 518 Context* HandleScopeImplementer::RestoreContext() {
 519   return saved_contexts_.RemoveLast();
 520 }
 521
 522
 523 bool HandleScopeImplementer::HasSavedContexts() {
 524   return !saved_contexts_.is_empty();
 525 }
 526
 527
 528 void HandleScopeImplementer::EnterContext(Handle<Object> context) {
 529   entered_contexts_.Add(context);
 530 }
 531
 532
 533 bool HandleScopeImplementer::LeaveLastContext() {
 534   if (entered_contexts_.is_empty()) return false;
 535   entered_contexts_.RemoveLast();
 536   return true;
 537 }
 538
 539
 540 Handle<Object> HandleScopeImplementer::LastEnteredContext() {
 541   if (entered_contexts_.is_empty()) return Handle<Object>::null();
 542   return entered_contexts_.last();
 543 }
 544
 545
 546 // If there's a spare block, use it for growing the current scope.
 547 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 548   internal::Object** block = (spare_ != NULL) ?
 549       spare_ :
 550       NewArray<internal::Object*>(kHandleBlockSize);
 551   spare_ = NULL;
 552   return block;
 553 }
 554
 555
 556 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 557   while (!blocks_.is_empty()) {
 558     internal::Object** block_start = blocks_.last();
 559     internal::Object** block_limit = block_start + kHandleBlockSize;
 560 #ifdef DEBUG
 561     // NoHandleAllocation may make the prev_limit to point inside the block.
 562     if (block_start <= prev_limit && prev_limit <= block_limit) break;
 563 #else
 564     if (prev_limit == block_limit) break;
 565 #endif
 566
 567     blocks_.RemoveLast();
 568 #ifdef DEBUG
 569     v8::ImplementationUtilities::ZapHandleRange(block_start, block_limit);
 570 #endif
 571     if (spare_ != NULL) {
 572       DeleteArray(spare_);
 573     }
 574     spare_ = block_start;
 575   }
 576   ASSERT((blocks_.is_empty() && prev_limit == NULL) ||
 577          (!blocks_.is_empty() && prev_limit != NULL));
 578 }
 579
 580
 581 class Testing {
 582  public:
 583   static v8::Testing::StressType stress_type() { return stress_type_; }
 584   static void set_stress_type(v8::Testing::StressType stress_type) {
 585     stress_type_ = stress_type;
 586   }
 587
 588  private:
 589   static v8::Testing::StressType stress_type_;
 590 };
 591
 592 } }  // namespace v8::internal
 593
 594 #endif  // V8_API_H_