src/api.h

   1 // Copyright 2012 the V8 project authors. All rights reserved.
   2 // Redistribution and use in source and binary forms, with or without
   3 // modification, are permitted provided that the following conditions are
   4 // met:
   5 //
   6 //     * Redistributions of source code must retain the above copyright
   7 //       notice, this list of conditions and the following disclaimer.
   8 //     * Redistributions in binary form must reproduce the above
   9 //       copyright notice, this list of conditions and the following
  10 //       disclaimer in the documentation and/or other materials provided
  11 //       with the distribution.
  12 //     * Neither the name of Google Inc. nor the names of its
  13 //       contributors may be used to endorse or promote products derived
  14 //       from this software without specific prior written permission.
  15 //
  16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  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   V(DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
 182
 183
 184 class Utils {
 185  public:
 186   static bool ReportApiFailure(const char* location, const char* message);
 187
 188   static Local<FunctionTemplate> ToFunctionTemplate(NeanderObject obj);
 189   static Local<ObjectTemplate> ToObjectTemplate(NeanderObject obj);
 190
 191   static inline Local<Context> ToLocal(
 192       v8::internal::Handle<v8::internal::Context> obj);
 193   static inline Local<Value> ToLocal(
 194       v8::internal::Handle<v8::internal::Object> obj);
 195   static inline Local<Function> ToLocal(
 196       v8::internal::Handle<v8::internal::JSFunction> obj);
 197   static inline Local<String> ToLocal(
 198       v8::internal::Handle<v8::internal::String> obj);
 199   static inline Local<RegExp> ToLocal(
 200       v8::internal::Handle<v8::internal::JSRegExp> obj);
 201   static inline Local<Object> ToLocal(
 202       v8::internal::Handle<v8::internal::JSObject> obj);
 203   static inline Local<Array> ToLocal(
 204       v8::internal::Handle<v8::internal::JSArray> obj);
 205   static inline Local<Message> MessageToLocal(
 206       v8::internal::Handle<v8::internal::Object> obj);
 207   static inline Local<StackTrace> StackTraceToLocal(
 208       v8::internal::Handle<v8::internal::JSArray> obj);
 209   static inline Local<StackFrame> StackFrameToLocal(
 210       v8::internal::Handle<v8::internal::JSObject> obj);
 211   static inline Local<Number> NumberToLocal(
 212       v8::internal::Handle<v8::internal::Object> obj);
 213   static inline Local<Integer> IntegerToLocal(
 214       v8::internal::Handle<v8::internal::Object> obj);
 215   static inline Local<Uint32> Uint32ToLocal(
 216       v8::internal::Handle<v8::internal::Object> obj);
 217   static inline Local<FunctionTemplate> ToLocal(
 218       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 219   static inline Local<ObjectTemplate> ToLocal(
 220       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
 221   static inline Local<Signature> ToLocal(
 222       v8::internal::Handle<v8::internal::SignatureInfo> obj);
 223   static inline Local<AccessorSignature> AccessorSignatureToLocal(
 224       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
 225   static inline Local<TypeSwitch> ToLocal(
 226       v8::internal::Handle<v8::internal::TypeSwitchInfo> obj);
 227   static inline Local<External> ExternalToLocal(
 228       v8::internal::Handle<v8::internal::JSObject> obj);
 229   static inline Local<DeclaredAccessorDescriptor> ToLocal(
 230       v8::internal::Handle<v8::internal::DeclaredAccessorDescriptor> obj);
 231
 232 #define DECLARE_OPEN_HANDLE(From, To) \
 233   static inline v8::internal::Handle<v8::internal::To> \
 234       OpenHandle(const From* that, bool allow_empty_handle = false);
 235
 236 OPEN_HANDLE_LIST(DECLARE_OPEN_HANDLE)
 237
 238 #undef DECLARE_OPEN_HANDLE
 239 };
 240
 241
 242 template <class T>
 243 inline T* ToApi(v8::internal::Handle<v8::internal::Object> obj) {
 244   return reinterpret_cast<T*>(obj.location());
 245 }
 246
 247
 248 template <class T>
 249 v8::internal::Handle<T> v8::internal::Handle<T>::EscapeFrom(
 250     v8::HandleScope* scope) {
 251   v8::internal::Handle<T> handle;
 252   if (!is_null()) {
 253     handle = *this;
 254   }
 255   return Utils::OpenHandle(*scope->Close(Utils::ToLocal(handle)), true);
 256 }
 257
 258
 259 // Implementations of ToLocal
 260
 261 #define MAKE_TO_LOCAL(Name, From, To)                                       \
 262   Local<v8::To> Utils::Name(v8::internal::Handle<v8::internal::From> obj) { \
 263     ASSERT(obj.is_null() || !obj->IsTheHole());                             \
 264     return Local<To>(reinterpret_cast<To*>(obj.location()));                \
 265   }
 266
 267 MAKE_TO_LOCAL(ToLocal, Context, Context)
 268 MAKE_TO_LOCAL(ToLocal, Object, Value)
 269 MAKE_TO_LOCAL(ToLocal, JSFunction, Function)
 270 MAKE_TO_LOCAL(ToLocal, String, String)
 271 MAKE_TO_LOCAL(ToLocal, JSRegExp, RegExp)
 272 MAKE_TO_LOCAL(ToLocal, JSObject, Object)
 273 MAKE_TO_LOCAL(ToLocal, JSArray, Array)
 274 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
 275 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
 276 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
 277 MAKE_TO_LOCAL(AccessorSignatureToLocal, FunctionTemplateInfo, AccessorSignature)
 278 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
 279 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
 280 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
 281 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
 282 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
 283 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
 284 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
 285 MAKE_TO_LOCAL(ExternalToLocal, JSObject, External)
 286 MAKE_TO_LOCAL(ToLocal, DeclaredAccessorDescriptor, DeclaredAccessorDescriptor)
 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, bool allow_empty_handle) {                        \
 296     EXTRA_CHECK(allow_empty_handle || that != NULL);                        \
 297     return v8::internal::Handle<v8::internal::To>(                          \
 298         reinterpret_cast<v8::internal::To**>(const_cast<v8::From*>(that))); \
 299   }
 300
 301 OPEN_HANDLE_LIST(MAKE_OPEN_HANDLE)
 302
 303 #undef MAKE_OPEN_HANDLE
 304 #undef OPEN_HANDLE_LIST
 305
 306
 307 namespace internal {
 308
 309 // Tracks string usage to help make better decisions when
 310 // externalizing strings.
 311 //
 312 // Implementation note: internally this class only tracks fresh
 313 // strings and keeps a single use counter for them.
 314 class StringTracker {
 315  public:
 316   // Records that the given string's characters were copied to some
 317   // external buffer. If this happens often we should honor
 318   // externalization requests for the string.
 319   void RecordWrite(Handle<String> string) {
 320     Address address = reinterpret_cast<Address>(*string);
 321     Address top = isolate_->heap()->NewSpaceTop();
 322     if (IsFreshString(address, top)) {
 323       IncrementUseCount(top);
 324     }
 325   }
 326
 327   // Estimates freshness and use frequency of the given string based
 328   // on how close it is to the new space top and the recorded usage
 329   // history.
 330   inline bool IsFreshUnusedString(Handle<String> string) {
 331     Address address = reinterpret_cast<Address>(*string);
 332     Address top = isolate_->heap()->NewSpaceTop();
 333     return IsFreshString(address, top) && IsUseCountLow(top);
 334   }
 335
 336  private:
 337   StringTracker() : use_count_(0), last_top_(NULL), isolate_(NULL) { }
 338
 339   static inline bool IsFreshString(Address string, Address top) {
 340     return top - kFreshnessLimit <= string && string <= top;
 341   }
 342
 343   inline bool IsUseCountLow(Address top) {
 344     if (last_top_ != top) return true;
 345     return use_count_ < kUseLimit;
 346   }
 347
 348   inline void IncrementUseCount(Address top) {
 349     if (last_top_ != top) {
 350       use_count_ = 0;
 351       last_top_ = top;
 352     }
 353     ++use_count_;
 354   }
 355
 356   // Single use counter shared by all fresh strings.
 357   int use_count_;
 358
 359   // Last new space top when the use count above was valid.
 360   Address last_top_;
 361
 362   Isolate* isolate_;
 363
 364   // How close to the new space top a fresh string has to be.
 365   static const int kFreshnessLimit = 1024;
 366
 367   // The number of uses required to consider a string useful.
 368   static const int kUseLimit = 32;
 369
 370   friend class Isolate;
 371
 372   DISALLOW_COPY_AND_ASSIGN(StringTracker);
 373 };
 374
 375
 376 class DeferredHandles {
 377  public:
 378   ~DeferredHandles();
 379
 380  private:
 381   DeferredHandles(Object** first_block_limit, Isolate* isolate)
 382       : next_(NULL),
 383         previous_(NULL),
 384         first_block_limit_(first_block_limit),
 385         isolate_(isolate) {
 386     isolate->LinkDeferredHandles(this);
 387   }
 388
 389   void Iterate(ObjectVisitor* v);
 390
 391   List<Object**> blocks_;
 392   DeferredHandles* next_;
 393   DeferredHandles* previous_;
 394   Object** first_block_limit_;
 395   Isolate* isolate_;
 396
 397   friend class HandleScopeImplementer;
 398   friend class Isolate;
 399 };
 400
 401
 402 // This class is here in order to be able to declare it a friend of
 403 // HandleScope.  Moving these methods to be members of HandleScope would be
 404 // neat in some ways, but it would expose internal implementation details in
 405 // our public header file, which is undesirable.
 406 //
 407 // An isolate has a single instance of this class to hold the current thread's
 408 // data. In multithreaded V8 programs this data is copied in and out of storage
 409 // so that the currently executing thread always has its own copy of this
 410 // data.
 411 class HandleScopeImplementer {
 412  public:
 413   explicit HandleScopeImplementer(Isolate* isolate)
 414       : isolate_(isolate),
 415         blocks_(0),
 416         entered_contexts_(0),
 417         saved_contexts_(0),
 418         spare_(NULL),
 419         call_depth_(0),
 420         last_handle_before_deferred_block_(NULL) { }
 421
 422   ~HandleScopeImplementer() {
 423     DeleteArray(spare_);
 424   }
 425
 426   // Threading support for handle data.
 427   static int ArchiveSpacePerThread();
 428   char* RestoreThread(char* from);
 429   char* ArchiveThread(char* to);
 430   void FreeThreadResources();
 431
 432   // Garbage collection support.
 433   void Iterate(v8::internal::ObjectVisitor* v);
 434   static char* Iterate(v8::internal::ObjectVisitor* v, char* data);
 435
 436
 437   inline internal::Object** GetSpareOrNewBlock();
 438   inline void DeleteExtensions(internal::Object** prev_limit);
 439
 440   inline void IncrementCallDepth() {call_depth_++;}
 441   inline void DecrementCallDepth() {call_depth_--;}
 442   inline bool CallDepthIsZero() { return call_depth_ == 0; }
 443
 444   inline void EnterContext(Handle<Object> context);
 445   inline bool LeaveLastContext();
 446
 447   // Returns the last entered context or an empty handle if no
 448   // contexts have been entered.
 449   inline Handle<Object> LastEnteredContext();
 450
 451   inline void SaveContext(Context* context);
 452   inline Context* RestoreContext();
 453   inline bool HasSavedContexts();
 454
 455   inline List<internal::Object**>* blocks() { return &blocks_; }
 456   Isolate* isolate() const { return isolate_; }
 457
 458   void ReturnBlock(Object** block) {
 459     ASSERT(block != NULL);
 460     if (spare_ != NULL) DeleteArray(spare_);
 461     spare_ = block;
 462   }
 463
 464  private:
 465   void ResetAfterArchive() {
 466     blocks_.Initialize(0);
 467     entered_contexts_.Initialize(0);
 468     saved_contexts_.Initialize(0);
 469     spare_ = NULL;
 470     last_handle_before_deferred_block_ = NULL;
 471     call_depth_ = 0;
 472   }
 473
 474   void Free() {
 475     ASSERT(blocks_.length() == 0);
 476     ASSERT(entered_contexts_.length() == 0);
 477     ASSERT(saved_contexts_.length() == 0);
 478     blocks_.Free();
 479     entered_contexts_.Free();
 480     saved_contexts_.Free();
 481     if (spare_ != NULL) {
 482       DeleteArray(spare_);
 483       spare_ = NULL;
 484     }
 485     ASSERT(call_depth_ == 0);
 486   }
 487
 488   void BeginDeferredScope();
 489   DeferredHandles* Detach(Object** prev_limit);
 490
 491   Isolate* isolate_;
 492   List<internal::Object**> blocks_;
 493   // Used as a stack to keep track of entered contexts.
 494   List<Handle<Object> > entered_contexts_;
 495   // Used as a stack to keep track of saved contexts.
 496   List<Context*> saved_contexts_;
 497   Object** spare_;
 498   int call_depth_;
 499   Object** last_handle_before_deferred_block_;
 500   // This is only used for threading support.
 501   v8::ImplementationUtilities::HandleScopeData handle_scope_data_;
 502
 503   void IterateThis(ObjectVisitor* v);
 504   char* RestoreThreadHelper(char* from);
 505   char* ArchiveThreadHelper(char* to);
 506
 507   friend class DeferredHandles;
 508   friend class DeferredHandleScope;
 509
 510   DISALLOW_COPY_AND_ASSIGN(HandleScopeImplementer);
 511 };
 512
 513
 514 const int kHandleBlockSize = v8::internal::KB - 2;  // fit in one page
 515
 516
 517 void HandleScopeImplementer::SaveContext(Context* context) {
 518   saved_contexts_.Add(context);
 519 }
 520
 521
 522 Context* HandleScopeImplementer::RestoreContext() {
 523   return saved_contexts_.RemoveLast();
 524 }
 525
 526
 527 bool HandleScopeImplementer::HasSavedContexts() {
 528   return !saved_contexts_.is_empty();
 529 }
 530
 531
 532 void HandleScopeImplementer::EnterContext(Handle<Object> context) {
 533   entered_contexts_.Add(context);
 534 }
 535
 536
 537 bool HandleScopeImplementer::LeaveLastContext() {
 538   if (entered_contexts_.is_empty()) return false;
 539   entered_contexts_.RemoveLast();
 540   return true;
 541 }
 542
 543
 544 Handle<Object> HandleScopeImplementer::LastEnteredContext() {
 545   if (entered_contexts_.is_empty()) return Handle<Object>::null();
 546   return entered_contexts_.last();
 547 }
 548
 549
 550 // If there's a spare block, use it for growing the current scope.
 551 internal::Object** HandleScopeImplementer::GetSpareOrNewBlock() {
 552   internal::Object** block = (spare_ != NULL) ?
 553       spare_ :
 554       NewArray<internal::Object*>(kHandleBlockSize);
 555   spare_ = NULL;
 556   return block;
 557 }
 558
 559
 560 void HandleScopeImplementer::DeleteExtensions(internal::Object** prev_limit) {
 561   while (!blocks_.is_empty()) {
 562     internal::Object** block_start = blocks_.last();
 563     internal::Object** block_limit = block_start + kHandleBlockSize;
 564 #ifdef DEBUG
 565     // NoHandleAllocation may make the prev_limit to point inside the block.
 566     if (block_start <= prev_limit && prev_limit <= block_limit) break;
 567 #else
 568     if (prev_limit == block_limit) break;
 569 #endif
 570
 571     blocks_.RemoveLast();
 572 #ifdef DEBUG
 573     v8::ImplementationUtilities::ZapHandleRange(block_start, block_limit);
 574 #endif
 575     if (spare_ != NULL) {
 576       DeleteArray(spare_);
 577     }
 578     spare_ = block_start;
 579   }
 580   ASSERT((blocks_.is_empty() && prev_limit == NULL) ||
 581          (!blocks_.is_empty() && prev_limit != NULL));
 582 }
 583
 584
 585 class Testing {
 586  public:
 587   static v8::Testing::StressType stress_type() { return stress_type_; }
 588   static void set_stress_type(v8::Testing::StressType stress_type) {
 589     stress_type_ = stress_type;
 590   }
 591
 592  private:
 593   static v8::Testing::StressType stress_type_;
 594 };
 595
 596 } }  // namespace v8::internal
 597
 598 #endif  // V8_API_H_