Add empty-handle checks to API functions (#ifdef ENABLE_EXTRA_CHECKS)
[platform/upstream/v8.git] / 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<External> ToLocal(
205       v8::internal::Handle<v8::internal::Foreign> obj);
206   static inline Local<Message> MessageToLocal(
207       v8::internal::Handle<v8::internal::Object> obj);
208   static inline Local<StackTrace> StackTraceToLocal(
209       v8::internal::Handle<v8::internal::JSArray> obj);
210   static inline Local<StackFrame> StackFrameToLocal(
211       v8::internal::Handle<v8::internal::JSObject> obj);
212   static inline Local<Number> NumberToLocal(
213       v8::internal::Handle<v8::internal::Object> obj);
214   static inline Local<Integer> IntegerToLocal(
215       v8::internal::Handle<v8::internal::Object> obj);
216   static inline Local<Uint32> Uint32ToLocal(
217       v8::internal::Handle<v8::internal::Object> obj);
218   static inline Local<FunctionTemplate> ToLocal(
219       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
220   static inline Local<ObjectTemplate> ToLocal(
221       v8::internal::Handle<v8::internal::ObjectTemplateInfo> obj);
222   static inline Local<Signature> ToLocal(
223       v8::internal::Handle<v8::internal::SignatureInfo> obj);
224   static inline Local<AccessorSignature> AccessorSignatureToLocal(
225       v8::internal::Handle<v8::internal::FunctionTemplateInfo> obj);
226   static inline Local<TypeSwitch> ToLocal(
227       v8::internal::Handle<v8::internal::TypeSwitchInfo> 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, Foreign, External)
272 MAKE_TO_LOCAL(ToLocal, FunctionTemplateInfo, FunctionTemplate)
273 MAKE_TO_LOCAL(ToLocal, ObjectTemplateInfo, ObjectTemplate)
274 MAKE_TO_LOCAL(ToLocal, SignatureInfo, Signature)
275 MAKE_TO_LOCAL(AccessorSignatureToLocal, FunctionTemplateInfo, AccessorSignature)
276 MAKE_TO_LOCAL(ToLocal, TypeSwitchInfo, TypeSwitch)
277 MAKE_TO_LOCAL(MessageToLocal, Object, Message)
278 MAKE_TO_LOCAL(StackTraceToLocal, JSArray, StackTrace)
279 MAKE_TO_LOCAL(StackFrameToLocal, JSObject, StackFrame)
280 MAKE_TO_LOCAL(NumberToLocal, Object, Number)
281 MAKE_TO_LOCAL(IntegerToLocal, Object, Integer)
282 MAKE_TO_LOCAL(Uint32ToLocal, Object, Uint32)
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_