objects.h.svn-base

Google浏览器V8内核代码

  // Useful when the map pointer field is used for other purposes.
  // GC internal.
  inline int SizeFromMap(Map* map);

  // Support for the marking heap objects during the marking phase of GC.
  // True if the object is marked live.
  inline bool IsMarked();

  // Mutate this object's map pointer to indicate that the object is live.
  inline void SetMark();

  // Mutate this object's map pointer to remove the indication that the
  // object is live (ie, partially restore the map pointer).
  inline void ClearMark();

  // True if this object is marked as overflowed.  Overflowed objects have
  // been reached and marked during marking of the heap, but their children
  // have not necessarily been marked and they have not been pushed on the
  // marking stack.
  inline bool IsOverflowed();

  // Mutate this object's map pointer to indicate that the object is
  // overflowed.
  inline void SetOverflow();

  // Mutate this object's map pointer to remove the indication that the
  // object is overflowed (ie, partially restore the map pointer).
  inline void ClearOverflow();

  static inline Object* GetHeapObjectField(HeapObject* obj, int index);

  // Casting.
  static inline HeapObject* cast(Object* obj);

  // Dispatched behavior.
  void HeapObjectShortPrint(StringStream* accumulator);
#ifdef DEBUG
  void HeapObjectPrint();
  void HeapObjectVerify();
  inline void VerifyObjectField(int offset);

  void PrintHeader(const char* id);

  // Verify a pointer is a valid HeapObject pointer that points to object
  // areas in the heap.
  static void VerifyHeapPointer(Object* p);
#endif

  // Layout description.
  // First field in a heap object is map.
  static const int kMapOffset = Object::kHeaderSize;
  static const int kHeaderSize = kMapOffset + kPointerSize;

 protected:
  // helpers for calling an ObjectVisitor to iterate over pointers in the
  // half-open range [start, end) specified as integer offsets
  inline void IteratePointers(ObjectVisitor* v, int start, int end);
  // as above, for the single element at "offset"
  inline void IteratePointer(ObjectVisitor* v, int offset);

  // Computes the object size from the map.
  // Should only be used from SizeFromMap.
  int SlowSizeFromMap(Map* map);

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(HeapObject);
};


// The HeapNumber class describes heap allocated numbers that cannot be
// represented in a Smi (small integer)
class HeapNumber: public HeapObject {
 public:
  // [value]: number value.
  inline double value();
  inline void set_value(double value);

  // Casting.
  static inline HeapNumber* cast(Object* obj);

  // Dispatched behavior.
  Object* HeapNumberToBoolean();
  void HeapNumberPrint();
  void HeapNumberPrint(StringStream* accumulator);
#ifdef DEBUG
  void HeapNumberVerify();
#endif

  // Layout description.
  static const int kValueOffset = HeapObject::kHeaderSize;
  static const int kSize = kValueOffset + kDoubleSize;

 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(HeapNumber);
};


// The JSObject describes real heap allocated JavaScript objects with
// properties.
// Note that the map of JSObject changes during execution to enable inline
// caching.
class JSObject: public HeapObject {
 public:
  // [properties]: Backing storage for properties.
  // properties is a FixedArray in the fast case, and a Dictionary in the
  // slow case.
  DECL_ACCESSORS(properties, FixedArray)  // Get and set fast properties.
  inline void initialize_properties();
  inline bool HasFastProperties();
  inline Dictionary* property_dictionary();  // Gets slow properties.

  // [elements]: The elements (properties with names that are integers).
  // elements is a FixedArray in the fast case, and a Dictionary in the slow
  // case.
  DECL_ACCESSORS(elements, HeapObject)  // Get and set fast elements.
  inline void initialize_elements();
  inline bool HasFastElements();
  inline Dictionary* element_dictionary();  // Gets slow elements.

  Object* SetProperty(String* key,
                      Object* value,
                      PropertyAttributes attributes);
  Object* SetProperty(LookupResult* result,
                      String* key,
                      Object* value,
                      PropertyAttributes attributes);
  Object* SetPropertyWithFailedAccessCheck(LookupResult* result,
                                           String* name,
                                           Object* value);
  Object* SetPropertyWithCallback(Object* structure,
                                  String* name,
                                  Object* value,
                                  JSObject* holder);
  Object* SetPropertyWithInterceptor(String* name,
                                     Object* value,
                                     PropertyAttributes attributes);
  Object* SetPropertyPostInterceptor(String* name,
                                     Object* value,
                                     PropertyAttributes attributes);
  Object* IgnoreAttributesAndSetLocalProperty(String* key,
                                              Object* value);

  // Sets a property that currently has lazy loading.
  Object* SetLazyProperty(LookupResult* result,
                          String* name,
                          Object* value,
                          PropertyAttributes attributes);

  // Returns the class name ([[Class]] property in the specification).
  String* class_name();

  // Retrieve interceptors.
  InterceptorInfo* GetNamedInterceptor();
  InterceptorInfo* GetIndexedInterceptor();

  inline PropertyAttributes GetPropertyAttribute(String* name);
  PropertyAttributes GetPropertyAttributeWithReceiver(JSObject* receiver,
                                                      String* name);
  PropertyAttributes GetLocalPropertyAttribute(String* name);

  Object* DefineAccessor(String* name, bool is_getter, JSFunction* fun,
                         PropertyAttributes attributes);
  Object* LookupAccessor(String* name, bool is_getter);

  // Used from Object::GetProperty().
  Object* GetPropertyWithFailedAccessCheck(Object* receiver,
                                           LookupResult* result,
                                           String* name);
  Object* GetPropertyWithInterceptor(JSObject* receiver,
                                     String* name,
                                     PropertyAttributes* attributes);
  Object* GetPropertyPostInterceptor(JSObject* receiver,
                                     String* name,
                                     PropertyAttributes* attributes);
  Object* GetLazyProperty(Object* receiver,
                          LookupResult* result,
                          String* name,
                          PropertyAttributes* attributes);

  bool HasProperty(String* name) {
    return GetPropertyAttribute(name) != ABSENT;
  }

  bool HasLocalProperty(String* name) {
    return GetLocalPropertyAttribute(name) != ABSENT;
  }

  Object* DeleteProperty(String* name);
  Object* DeleteElement(uint32_t index);
  Object* DeleteLazyProperty(LookupResult* result, String* name);

  // Tests for the fast common case for property enumeration.
  bool IsSimpleEnum();

  // Do we want to keep the elements in fast case when increasing the
  // capacity?
  bool ShouldConvertToSlowElements(int new_capacity);
  // Returns true if the backing storage for the slow-case elements of
  // this object takes up nearly as much space as a fast-case backing
  // storage would.  In that case the JSObject should have fast
  // elements.
  bool ShouldConvertToFastElements();

  // Return the object's prototype (might be Heap::null_value()).
  inline Object* GetPrototype();

  // Tells whether the index'th element is present.
  inline bool HasElement(uint32_t index);
  bool HasElementWithReceiver(JSObject* receiver, uint32_t index);
  bool HasLocalElement(uint32_t index);

  bool HasElementWithInterceptor(JSObject* receiver, uint32_t index);
  bool HasElementPostInterceptor(JSObject* receiver, uint32_t index);

  Object* SetFastElement(uint32_t index, Object* value);

  // Set the index'th array element.
  // A Failure object is returned if GC is needed.
  Object* SetElement(uint32_t index, Object* value);

  // Returns the index'th element.
  // The undefined object if index is out of bounds.
  Object* GetElementWithReceiver(JSObject* receiver, uint32_t index);

  void SetFastElements(FixedArray* elements);
  Object* SetSlowElements(Object* length);

  // Lookup interceptors are used for handling properties controlled by host
  // objects.
  inline bool HasNamedInterceptor();
  inline bool HasIndexedInterceptor();

  // Support functions for v8 api (needed for correct interceptor behavior).
  bool HasRealNamedProperty(String* key);
  bool HasRealElementProperty(uint32_t index);
  bool HasRealNamedCallbackProperty(String* key);

  // Initializes the array to a certain length
  Object* SetElementsLength(Object* length);

  // Get the header size for a JSObject.  Used to compute the index of
  // internal fields as well as the number of internal fields.
  inline int GetHeaderSize();

  inline int GetInternalFieldCount();
  inline Object* GetInternalField(int index);
  inline void SetInternalField(int index, Object* value);

  // Returns a deep copy of the JavaScript object.
  // Properties and elements are copied too.
  // Returns failure if allocation failed.
  Object* Copy(PretenureFlag pretenure = NOT_TENURED);

  // Lookup a property.  If found, the result is valid and has
  // detailed information.
  void LocalLookup(String* name, LookupResult* result);
  void Lookup(String* name, LookupResult* result);

  // The following lookup functions skip interceptors.
  void LocalLookupRealNamedProperty(String* name, LookupResult* result);
  void LookupRealNamedProperty(String* name, LookupResult* result);
  void LookupRealNamedPropertyInPrototypes(String* name, LookupResult* result);
  void LookupCallbackSetterInPrototypes(String* name, LookupResult* result);

  // Returns the number of properties on this object filtering out properties
  // with the specified attributes (ignoring interceptors).
  int NumberOfLocalProperties(PropertyAttributes filter);
  // Returns the number of enumerable properties (ignoring interceptors).
  int NumberOfEnumProperties();
  // Fill in details for properties into storage.
  void GetLocalPropertyNames(FixedArray* storage);

  // Returns the number of properties on this object filtering out properties
  // with the specified attributes (ignoring interceptors).
  int NumberOfLocalElements(PropertyAttributes filter);
  // Returns the number of enumerable elements (ignoring interceptors).
  int NumberOfEnumElements();
  // Returns the number of elements on this object filtering out elements
  // with the specified attributes (ignoring interceptors).
  int GetLocalElementKeys(FixedArray* storage, PropertyAttributes filter);
  // Count and fill in the enumerable elements into storage.
  // (storage->length() == NumberOfEnumElements()).
  // If storage is NULL, will count the elements without adding
  // them to any storage.
  // Returns the number of enumerable elements.
  int GetEnumElementKeys(FixedArray* storage);

  // Add a property to a fast-case object using a map transition to
  // new_map.
  Object* AddFastPropertyUsingMap(Map* new_map,
                                  String* name,
                                  Object* value);

  // Add a constant function property to a fast-case object.
  // This leaves a CONSTANT_TRANSITION in the old map, and
  // if it is called on a second object with this map, a
  // normal property is added instead, with a map transition.
  // This avoids the creation of many maps with the same constant
  // function, all orphaned.
  Object* AddConstantFunctionProperty(String* name,
                                      JSFunction* function,
                                      PropertyAttributes attributes);

  // Replace a constant function property on a fast-case object.
  Object* ReplaceConstantFunctionProperty(String* name,
                                          Object* value);

  // Add a property to a fast-case object.
  Object* AddFastProperty(String* name,
                          Object* value,
                          PropertyAttributes attributes);

  // Add a property to a slow-case object.
  Object* AddSlowProperty(String* name,
                          Object* value,
                          PropertyAttributes attributes);

  // Add a property to an object.
  Object* AddProperty(String* name,
                      Object* value,
                      PropertyAttributes attributes);

  // Convert the object to use the canonical dictionary
  // representation.
  Object* NormalizeProperties();
  Object* NormalizeElements();

  // Transform slow named properties to fast variants.
  // Returns failure if allocation failed.
  Object* TransformToFastProperties(int unused_property_fields);

  // initializes the body after properties slot, properties slot is
  // initialized by set_properties