objects.cc.svn-base

Google浏览器V8内核代码

      Map::cast(new_map)->
        set_instance_descriptors(DescriptorArray::cast(new_descriptors));
      Map::cast(new_map)->
        set_unused_property_fields(map()->unused_property_fields()-1);
      set_map(Map::cast(new_map));
      properties()->set(index, value);
    } else {
      ASSERT(map()->unused_property_fields() == 0);
      static const int kFastNofProperties = 20;
      if (properties()->length() > kFastNofProperties) {
        Object* obj = NormalizeProperties();
        if (obj->IsFailure()) return obj;
        return SetProperty(name, value, NONE);
      }

      static const int kExtraFields = 5;
      // Make room for the more properties.
      Object* values =
          properties()->CopySize(properties()->length() + kExtraFields);
      if (values->IsFailure()) return values;
      FixedArray::cast(values)->set(index, value);

      // Allocate a new map for the object.
      Object* new_map = map()->Copy();
      if (new_map->IsFailure()) return new_map;

      Map::cast(new_map)->
        set_instance_descriptors(DescriptorArray::cast(new_descriptors));
      Map::cast(new_map)->
        set_unused_property_fields(kExtraFields - 1);
      set_map(Map::cast(new_map));
      set_properties(FixedArray::cast(values));
    }
  }
  return value;
}


// Add property in slow mode
Object* JSObject::AddSlowProperty(String* name,
                                  Object* value,
                                  PropertyAttributes attributes) {
  PropertyDetails details = PropertyDetails(attributes, NORMAL);
  Object* result = property_dictionary()->AddStringEntry(name, value, details);
  if (result->IsFailure()) return result;
  if (property_dictionary() != result) {
     set_properties(Dictionary::cast(result));
  }
  return value;
}


Object* JSObject::AddProperty(String* name,
                              Object* value,
                              PropertyAttributes attributes) {
  if (HasFastProperties()) {
    // Ensure the descriptor array does not get too big.
    if (map()->instance_descriptors()->number_of_descriptors() <
        DescriptorArray::kMaxNumberOfDescriptors) {
      if (value->IsJSFunction()) {
        return AddConstantFunctionProperty(name,
                                           JSFunction::cast(value),
                                           attributes);
      } else {
        return AddFastProperty(name, value, attributes);
      }
    } else {
      // Normalize the object to prevent very large instance descriptors.
      // This eliminates unwanted N^2 allocation and lookup behavior.
      Object* obj = NormalizeProperties();
      if (obj->IsFailure()) return obj;
    }
  }
  return AddSlowProperty(name, value, attributes);
}


Object* JSObject::SetPropertyPostInterceptor(String* name,
                                             Object* value,
                                             PropertyAttributes attributes) {
  // Check local property, ignore interceptor.
  LookupResult result;
  LocalLookupRealNamedProperty(name, &result);
  if (result.IsValid()) return SetProperty(&result, name, value, attributes);
  // Add real property.
  return AddProperty(name, value, attributes);
}


Object* JSObject::SetPropertyWithInterceptor(String* name,
                                             Object* value,
                                             PropertyAttributes attributes) {
  HandleScope scope;
  Handle<JSObject> this_handle(this);
  Handle<String> name_handle(name);
  Handle<Object> value_handle(value);
  Handle<InterceptorInfo> interceptor(GetNamedInterceptor());
  if (!interceptor->setter()->IsUndefined()) {
    Handle<Object> data_handle(interceptor->data());
    LOG(ApiNamedPropertyAccess("interceptor-named-set", this, name));
    v8::AccessorInfo info(v8::Utils::ToLocal(this_handle),
                          v8::Utils::ToLocal(data_handle),
                          v8::Utils::ToLocal(this_handle));
    v8::NamedPropertySetter setter =
        v8::ToCData<v8::NamedPropertySetter>(interceptor->setter());
    v8::Handle<v8::Value> result;
    {
      // Leaving JavaScript.
      VMState state(OTHER);
      Handle<Object> value_unhole(value->IsTheHole() ?
                                  Heap::undefined_value() :
                                  value);
      result = setter(v8::Utils::ToLocal(name_handle),
                      v8::Utils::ToLocal(value_unhole),
                      info);
    }
    RETURN_IF_SCHEDULED_EXCEPTION();
    if (!result.IsEmpty()) return *value_handle;
  }
  Object* raw_result = this_handle->SetPropertyPostInterceptor(*name_handle,
                                                               *value_handle,
                                                               attributes);
  RETURN_IF_SCHEDULED_EXCEPTION();
  return raw_result;
}


Object* JSObject::SetProperty(String* name,
                              Object* value,
                              PropertyAttributes attributes) {
  LookupResult result;
  LocalLookup(name, &result);
  return SetProperty(&result, name, value, attributes);
}


Object* JSObject::SetPropertyWithCallback(Object* structure,
                                          String* name,
                                          Object* value,
                                          JSObject* holder) {
  HandleScope scope;

  // We should never get here to initialize a const with the hole
  // value since a const declaration would conflict with the setter.
  ASSERT(!value->IsTheHole());
  Handle<Object> value_handle(value);

  // To accommodate both the old and the new api we switch on the
  // data structure used to store the callbacks.  Eventually proxy
  // callbacks should be phased out.
  if (structure->IsProxy()) {
    AccessorDescriptor* callback =
        reinterpret_cast<AccessorDescriptor*>(Proxy::cast(structure)->proxy());
    Object* obj = (callback->setter)(this,  value, callback->data);
    RETURN_IF_SCHEDULED_EXCEPTION();
    if (obj->IsFailure()) return obj;
    return *value_handle;
  }

  if (structure->IsAccessorInfo()) {
    // api style callbacks
    AccessorInfo* data = AccessorInfo::cast(structure);
    Object* call_obj = data->setter();
    v8::AccessorSetter call_fun = v8::ToCData<v8::AccessorSetter>(call_obj);
    if (call_fun == NULL) return value;
    Handle<JSObject> self(this);
    Handle<JSObject> holder_handle(JSObject::cast(holder));
    Handle<String> key(name);
    Handle<Object> fun_data(data->data());
    LOG(ApiNamedPropertyAccess("store", this, name));
    v8::AccessorInfo info(v8::Utils::ToLocal(self),
                          v8::Utils::ToLocal(fun_data),
                          v8::Utils::ToLocal(holder_handle));
    {
      // Leaving JavaScript.
      VMState state(OTHER);
      call_fun(v8::Utils::ToLocal(key),
               v8::Utils::ToLocal(value_handle),
               info);
    }
    RETURN_IF_SCHEDULED_EXCEPTION();
    return *value_handle;
  }

  if (structure->IsFixedArray()) {
    Object* setter = FixedArray::cast(structure)->get(kSetterIndex);
    if (setter->IsJSFunction()) {
      Handle<JSFunction> fun(JSFunction::cast(setter));
      Handle<JSObject> self(this);
      bool has_pending_exception;
      Object** argv[] = { value_handle.location() };
      Execution::Call(fun, self, 1, argv, &has_pending_exception);
      // Check for pending exception and return the result.
      if (has_pending_exception) return Failure::Exception();
    } else {
      Handle<String> key(name);
      Handle<Object> holder_handle(holder);
      Handle<Object> args[2] = { key, holder_handle };
      return Top::Throw(*Factory::NewTypeError("no_setter_in_callback",
                                               HandleVector(args, 2)));
    }
    return *value_handle;
  }

  UNREACHABLE();
  return 0;
}


void JSObject::LookupCallbackSetterInPrototypes(String* name,
                                                LookupResult* result) {
  for (Object* pt = GetPrototype();
       pt != Heap::null_value();
       pt = pt->GetPrototype()) {
    JSObject::cast(pt)->LocalLookupRealNamedProperty(name, result);
    if (result->IsValid()) {
      if (!result->IsTransitionType() && result->IsReadOnly()) {
        result->NotFound();
        return;
      }
      if (result->type() == CALLBACKS) {
        return;
      }
    }
  }
  result->NotFound();
}


void JSObject::LookupInDescriptor(String* name, LookupResult* result) {
  DescriptorArray* descriptors = map()->instance_descriptors();
  int number = descriptors->Search(name);
  if (number != DescriptorArray::kNotFound) {
    result->DescriptorResult(this, descriptors->GetDetails(number), number);
  } else {
    result->NotFound();
  }
}


void JSObject::LocalLookupRealNamedProperty(String* name,
                                            LookupResult* result) {
  if (HasFastProperties()) {
    LookupInDescriptor(name, result);
    if (result->IsValid()) {
      ASSERT(result->holder() == this && result->type() != NORMAL);
      // Disallow caching for uninitialized constants. These can only
      // occur as fields.
      if (result->IsReadOnly() && result->type() == FIELD &&
          properties()->get(result->GetFieldIndex())->IsTheHole()) {
        result->DisallowCaching();
      }
      return;
    }
  } else {
    int entry = property_dictionary()->FindStringEntry(name);
    if (entry != DescriptorArray::kNotFound) {
      // Make sure to disallow caching for uninitialized constants
      // found in the dictionary-mode objects.
      if (property_dictionary()->ValueAt(entry)->IsTheHole()) {
        result->DisallowCaching();
      }
      result->DictionaryResult(this, entry);
      return;
    }
    // Slow case object skipped during lookup. Do not use inline caching.
    result->DisallowCaching();
  }
  result->NotFound();
}


void JSObject::LookupRealNamedProperty(String* name, LookupResult* result) {
  LocalLookupRealNamedProperty(name, result);
  if (result->IsProperty()) return;

  LookupRealNamedPropertyInPrototypes(name, result);
}


void JSObject::LookupRealNamedPropertyInPrototypes(String* name,
                                                   LookupResult* result) {
  for (Object* pt = GetPrototype();
       pt != Heap::null_value();
       pt = JSObject::cast(pt)->GetPrototype()) {
    JSObject::cast(pt)->LocalLookupRealNamedProperty(name, result);
    if (result->IsValid()) {
      switch (result->type()) {
        case NORMAL:
        case FIELD:
        case CONSTANT_FUNCTION:
        case CALLBACKS:
          return;
        default: break;
      }
    }
  }
  result->NotFound();
}


// We only need to deal with CALLBACKS and INTERCEPTORS
Object* JSObject::SetPropertyWithFailedAccessCheck(LookupResult* result,
                                                   String* name,
                                                   Object* value) {
  if (!result->IsProperty()) {
    LookupCallbackSetterInPrototypes(name, result);
  }

  if (result->IsProperty()) {
    if (!result->IsReadOnly()) {
      switch (result->type()) {
        case CALLBACKS: {
          Object* obj = result->GetCallbackObject();
          if (obj->IsAccessorInfo()) {
            AccessorInfo* info = AccessorInfo::cast(obj);
            if (info->all_can_write()) {
              return SetPropertyWithCallback(result->GetCallbackObject(),
                                             name,
                                             value,
                                             result->holder());
            }
          }
          break;
        }
        case INTERCEPTOR: {
          // Try lookup real named properties. Note that only property can be
          // set is callbacks marked as ALL_CAN_WRITE on the prototype chain.
          LookupResult r;
          LookupRealNamedProperty(name, &r);
          if (r.IsProperty()) {
            return SetPropertyWithFailedAccessCheck(&r, name, value);
          }
          break;
        }
        default: {
          break;
        }
      }
    }
  }

  Top::ReportFailedAccessCheck(this, v8::ACCESS_SET);
  return value;
}


Object* JSObject::SetProperty(LookupResult* result,
                              String* name,
                              Object* value,
                              PropertyAttributes attributes) {
  // Make sure that the top context does not change when doing callbacks or
  // interceptor calls.
  AssertNoContextChange ncc;

  // Check access rights if needed.
  if (IsAccessCheckNeeded()
    && !Top::MayNamedAccess(this, name, v8::ACCESS_SET)) {
    return SetPropertyWithFailedAccessCheck(result, name, value);
  }
  if (result->IsNotFound() || !result->IsProperty()) {
    // We could not find a local property so let's check whether there is an
    // accessor that wants to handle the property.
    LookupResult accessor_result;
    LookupCallbackSetterInPrototypes(name, &accessor_result);
    if (accessor_result.IsValid()) {
      return SetPropertyWithCallback(accessor_result.GetCallbackObject(),
                                     name,
                                     value,
                                     accessor_result.holder());
    }
  }
  if (result->IsNotFound()) {
    return AddProperty(name, value, attributes);
  }
  if (!result->IsLoaded()) {
    return SetLazyProperty(result, name, value, attributes);
  }
  if (result->IsReadOnly() && result->IsProperty()) return value;
  // This is a real property that is not read-only, or it is a
  // transition or null descriptor and there are no setters in the prototypes.