blob: 04f78b22d4431d27a40411c62d2d0b00a99ab734 [file] [log] [blame]
// Copyright 2012 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_PROPERTY_H_
#define V8_PROPERTY_H_
#include "allocation.h"
namespace v8 {
namespace internal {
// Abstraction for elements in instance-descriptor arrays.
//
// Each descriptor has a key, property attributes, property type,
// property index (in the actual instance-descriptor array) and
// optionally a piece of data.
//
class Descriptor BASE_EMBEDDED {
public:
static int IndexFromValue(Object* value) {
return Smi::cast(value)->value();
}
MUST_USE_RESULT MaybeObject* KeyToSymbol() {
if (!StringShape(key_).IsSymbol()) {
MaybeObject* maybe_result = HEAP->LookupSymbol(key_);
if (!maybe_result->To(&key_)) return maybe_result;
}
return key_;
}
String* GetKey() { return key_; }
Object* GetValue() { return value_; }
PropertyDetails GetDetails() { return details_; }
#ifdef OBJECT_PRINT
void Print(FILE* out);
#endif
void SetEnumerationIndex(int index) {
ASSERT(PropertyDetails::IsValidIndex(index));
details_ = PropertyDetails(details_.attributes(), details_.type(), index);
}
bool ContainsTransition();
private:
String* key_;
Object* value_;
PropertyDetails details_;
protected:
Descriptor() : details_(Smi::FromInt(0)) {}
void Init(String* key, Object* value, PropertyDetails details) {
key_ = key;
value_ = value;
details_ = details;
}
Descriptor(String* key, Object* value, PropertyDetails details)
: key_(key),
value_(value),
details_(details) { }
Descriptor(String* key,
Object* value,
PropertyAttributes attributes,
PropertyType type,
int index = 0)
: key_(key),
value_(value),
details_(attributes, type, index) { }
friend class DescriptorArray;
};
// A pointer from a map to the new map that is created by adding
// a named property. These are key to the speed and functioning of V8.
// The two maps should always have the same prototype, since
// MapSpace::CreateBackPointers depends on this.
class MapTransitionDescriptor: public Descriptor {
public:
MapTransitionDescriptor(String* key, Map* map, PropertyAttributes attributes)
: Descriptor(key, map, attributes, MAP_TRANSITION) { }
};
class ElementsTransitionDescriptor: public Descriptor {
public:
ElementsTransitionDescriptor(String* key,
Object* map_or_array)
: Descriptor(key, map_or_array, PropertyDetails(NONE,
ELEMENTS_TRANSITION)) { }
};
// Marks a field name in a map so that adding the field is guaranteed
// to create a FIELD descriptor in the new map. Used after adding
// a constant function the first time, creating a CONSTANT_FUNCTION
// descriptor in the new map. This avoids creating multiple maps with
// the same CONSTANT_FUNCTION field.
class ConstTransitionDescriptor: public Descriptor {
public:
explicit ConstTransitionDescriptor(String* key, Map* map)
: Descriptor(key, map, NONE, CONSTANT_TRANSITION) { }
};
class FieldDescriptor: public Descriptor {
public:
FieldDescriptor(String* key,
int field_index,
PropertyAttributes attributes,
int index = 0)
: Descriptor(key, Smi::FromInt(field_index), attributes, FIELD, index) {}
};
class ConstantFunctionDescriptor: public Descriptor {
public:
ConstantFunctionDescriptor(String* key,
JSFunction* function,
PropertyAttributes attributes,
int index = 0)
: Descriptor(key, function, attributes, CONSTANT_FUNCTION, index) {}
};
class CallbacksDescriptor: public Descriptor {
public:
CallbacksDescriptor(String* key,
Object* foreign,
PropertyAttributes attributes,
int index = 0)
: Descriptor(key, foreign, attributes, CALLBACKS, index) {}
};
template <class T>
bool IsPropertyDescriptor(T* desc) {
switch (desc->type()) {
case NORMAL:
case FIELD:
case CONSTANT_FUNCTION:
case HANDLER:
case INTERCEPTOR:
return true;
case CALLBACKS: {
Object* callback_object = desc->GetCallbackObject();
// Non-JavaScript (i.e. native) accessors are always a property, otherwise
// either the getter or the setter must be an accessor. Put another way:
// If we only see map transitions and holes in a pair, this is not a
// property.
return (!callback_object->IsAccessorPair() ||
AccessorPair::cast(callback_object)->ContainsAccessor());
}
case MAP_TRANSITION:
case ELEMENTS_TRANSITION:
case CONSTANT_TRANSITION:
case NULL_DESCRIPTOR:
return false;
}
UNREACHABLE(); // keep the compiler happy
return false;
}
class LookupResult BASE_EMBEDDED {
public:
explicit LookupResult(Isolate* isolate)
: isolate_(isolate),
next_(isolate->top_lookup_result()),
lookup_type_(NOT_FOUND),
holder_(NULL),
cacheable_(true),
details_(NONE, NORMAL) {
isolate->SetTopLookupResult(this);
}
~LookupResult() {
ASSERT(isolate_->top_lookup_result() == this);
isolate_->SetTopLookupResult(next_);
}
void DescriptorResult(JSObject* holder, PropertyDetails details, int number) {
lookup_type_ = DESCRIPTOR_TYPE;
holder_ = holder;
details_ = details;
number_ = number;
}
void DescriptorResult(JSObject* holder, Smi* details, int number) {
lookup_type_ = DESCRIPTOR_TYPE;
holder_ = holder;
details_ = PropertyDetails(details);
number_ = number;
}
void ConstantResult(JSObject* holder) {
lookup_type_ = CONSTANT_TYPE;
holder_ = holder;
details_ =
PropertyDetails(static_cast<PropertyAttributes>(DONT_ENUM |
DONT_DELETE),
CALLBACKS);
number_ = -1;
}
void DictionaryResult(JSObject* holder, int entry) {
lookup_type_ = DICTIONARY_TYPE;
holder_ = holder;
details_ = holder->property_dictionary()->DetailsAt(entry);
number_ = entry;
}
void HandlerResult(JSProxy* proxy) {
lookup_type_ = HANDLER_TYPE;
holder_ = proxy;
details_ = PropertyDetails(NONE, HANDLER);
cacheable_ = false;
}
void InterceptorResult(JSObject* holder) {
lookup_type_ = INTERCEPTOR_TYPE;
holder_ = holder;
details_ = PropertyDetails(NONE, INTERCEPTOR);
}
void NotFound() {
lookup_type_ = NOT_FOUND;
holder_ = NULL;
}
JSObject* holder() {
ASSERT(IsFound());
return JSObject::cast(holder_);
}
JSProxy* proxy() {
ASSERT(IsFound());
return JSProxy::cast(holder_);
}
PropertyType type() {
ASSERT(IsFound());
return details_.type();
}
PropertyAttributes GetAttributes() {
ASSERT(IsFound());
return details_.attributes();
}
PropertyDetails GetPropertyDetails() {
return details_;
}
bool IsReadOnly() { return details_.IsReadOnly(); }
bool IsDontDelete() { return details_.IsDontDelete(); }
bool IsDontEnum() { return details_.IsDontEnum(); }
bool IsDeleted() { return details_.IsDeleted(); }
bool IsFound() { return lookup_type_ != NOT_FOUND; }
bool IsHandler() { return lookup_type_ == HANDLER_TYPE; }
// Is the result is a property excluding transitions and the null descriptor?
bool IsProperty() {
return IsFound() && IsPropertyDescriptor(this);
}
bool IsCacheable() { return cacheable_; }
void DisallowCaching() { cacheable_ = false; }
Object* GetLazyValue() {
switch (type()) {
case FIELD:
return holder()->FastPropertyAt(GetFieldIndex());
case NORMAL: {
Object* value;
value = holder()->property_dictionary()->ValueAt(GetDictionaryEntry());
if (holder()->IsGlobalObject()) {
value = JSGlobalPropertyCell::cast(value)->value();
}
return value;
}
case CONSTANT_FUNCTION:
return GetConstantFunction();
default:
return Smi::FromInt(0);
}
}
Map* GetTransitionMap() {
ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
ASSERT(type() == MAP_TRANSITION ||
type() == ELEMENTS_TRANSITION ||
type() == CONSTANT_TRANSITION);
return Map::cast(GetValue());
}
Map* GetTransitionMapFromMap(Map* map) {
ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
ASSERT(type() == MAP_TRANSITION);
return Map::cast(map->instance_descriptors()->GetValue(number_));
}
int GetFieldIndex() {
ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
ASSERT(type() == FIELD);
return Descriptor::IndexFromValue(GetValue());
}
int GetLocalFieldIndexFromMap(Map* map) {
ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
ASSERT(type() == FIELD);
return Descriptor::IndexFromValue(
map->instance_descriptors()->GetValue(number_)) -
map->inobject_properties();
}
int GetDictionaryEntry() {
ASSERT(lookup_type_ == DICTIONARY_TYPE);
return number_;
}
JSFunction* GetConstantFunction() {
ASSERT(type() == CONSTANT_FUNCTION);
return JSFunction::cast(GetValue());
}
JSFunction* GetConstantFunctionFromMap(Map* map) {
ASSERT(lookup_type_ == DESCRIPTOR_TYPE);
ASSERT(type() == CONSTANT_FUNCTION);
return JSFunction::cast(map->instance_descriptors()->GetValue(number_));
}
Object* GetCallbackObject() {
if (lookup_type_ == CONSTANT_TYPE) {
// For now we only have the __proto__ as constant type.
return HEAP->prototype_accessors();
}
return GetValue();
}
#ifdef OBJECT_PRINT
void Print(FILE* out);
#endif
Object* GetValue() {
if (lookup_type_ == DESCRIPTOR_TYPE) {
DescriptorArray* descriptors = holder()->map()->instance_descriptors();
return descriptors->GetValue(number_);
}
// In the dictionary case, the data is held in the value field.
ASSERT(lookup_type_ == DICTIONARY_TYPE);
return holder()->GetNormalizedProperty(this);
}
void Iterate(ObjectVisitor* visitor);
private:
Isolate* isolate_;
LookupResult* next_;
// Where did we find the result;
enum {
NOT_FOUND,
DESCRIPTOR_TYPE,
DICTIONARY_TYPE,
HANDLER_TYPE,
INTERCEPTOR_TYPE,
CONSTANT_TYPE
} lookup_type_;
JSReceiver* holder_;
int number_;
bool cacheable_;
PropertyDetails details_;
};
} } // namespace v8::internal
#endif // V8_PROPERTY_H_