v8/src/api-natives.cc

// Copyright 2015 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/api-natives.h"

#include "src/api.h"
#include "src/isolate.h"
#include "src/lookup.h"
#include "src/messages.h"

namespace v8 {
namespace internal {


namespace {

MaybeHandle<JSObject> InstantiateObject(Isolate* isolate,
                                        Handle<ObjectTemplateInfo> data);


MaybeHandle<JSFunction> InstantiateFunction(Isolate* isolate,
                                            Handle<FunctionTemplateInfo> data,
                                            Handle<Name> name = Handle<Name>());


MaybeHandle<Object> Instantiate(Isolate* isolate, Handle<Object> data,
                                Handle<Name> name = Handle<Name>()) {
  if (data->IsFunctionTemplateInfo()) {
    return InstantiateFunction(isolate,
                               Handle<FunctionTemplateInfo>::cast(data), name);
  } else if (data->IsObjectTemplateInfo()) {
    return InstantiateObject(isolate, Handle<ObjectTemplateInfo>::cast(data));
  } else {
    return data;
  }
}


MaybeHandle<Object> DefineAccessorProperty(
    Isolate* isolate, Handle<JSObject> object, Handle<Name> name,
    Handle<Object> getter, Handle<Object> setter, Smi* attributes) {
  DCHECK(PropertyDetails::AttributesField::is_valid(
      static_cast<PropertyAttributes>(attributes->value())));
  if (!getter->IsUndefined()) {
    ASSIGN_RETURN_ON_EXCEPTION(
        isolate, getter,
        InstantiateFunction(isolate,
                            Handle<FunctionTemplateInfo>::cast(getter)),
        Object);
  }
  if (!setter->IsUndefined()) {
    ASSIGN_RETURN_ON_EXCEPTION(
        isolate, setter,
        InstantiateFunction(isolate,
                            Handle<FunctionTemplateInfo>::cast(setter)),
        Object);
  }
  RETURN_ON_EXCEPTION(isolate,
                      JSObject::DefineAccessor(
                          object, name, getter, setter,
                          static_cast<PropertyAttributes>(attributes->value())),
                      Object);
  return object;
}


MaybeHandle<Object> DefineDataProperty(Isolate* isolate,
                                       Handle<JSObject> object,
                                       Handle<Name> key,
                                       Handle<Object> prop_data,
                                       Smi* unchecked_attributes) {
  DCHECK((unchecked_attributes->value() &
          ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
  // Compute attributes.
  PropertyAttributes attributes =
      static_cast<PropertyAttributes>(unchecked_attributes->value());

  Handle<Object> value;
  ASSIGN_RETURN_ON_EXCEPTION(isolate, value,
                             Instantiate(isolate, prop_data, key), Object);

#ifdef DEBUG
  bool duplicate;
  if (key->IsName()) {
    LookupIterator it(object, Handle<Name>::cast(key),
                      LookupIterator::OWN_SKIP_INTERCEPTOR);
    Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
    DCHECK(maybe.IsJust());
    duplicate = it.IsFound();
  } else {
    uint32_t index = 0;
    key->ToArrayIndex(&index);
    Maybe<bool> maybe = JSReceiver::HasOwnElement(object, index);
    if (!maybe.IsJust()) return MaybeHandle<Object>();
    duplicate = maybe.FromJust();
  }
  if (duplicate) {
    THROW_NEW_ERROR(
        isolate, NewTypeError(MessageTemplate::kDuplicateTemplateProperty, key),
        Object);
  }
#endif

  RETURN_ON_EXCEPTION(
      isolate, Runtime::DefineObjectProperty(object, key, value, attributes),
      Object);
  return object;
}


void DisableAccessChecks(Isolate* isolate, Handle<JSObject> object) {
  Handle<Map> old_map(object->map());
  // Copy map so it won't interfere constructor's initial map.
  Handle<Map> new_map = Map::Copy(old_map, "DisableAccessChecks");
  new_map->set_is_access_check_needed(false);
  JSObject::MigrateToMap(Handle<JSObject>::cast(object), new_map);
}


void EnableAccessChecks(Isolate* isolate, Handle<JSObject> object) {
  Handle<Map> old_map(object->map());
  // Copy map so it won't interfere constructor's initial map.
  Handle<Map> new_map = Map::Copy(old_map, "EnableAccessChecks");
  new_map->set_is_access_check_needed(true);
  JSObject::MigrateToMap(object, new_map);
}


class AccessCheckDisableScope {
 public:
  AccessCheckDisableScope(Isolate* isolate, Handle<JSObject> obj)
      : isolate_(isolate),
        disabled_(obj->map()->is_access_check_needed()),
        obj_(obj) {
    if (disabled_) {
      DisableAccessChecks(isolate_, obj_);
    }
  }
  ~AccessCheckDisableScope() {
    if (disabled_) {
      EnableAccessChecks(isolate_, obj_);
    }
  }

 private:
  Isolate* isolate_;
  const bool disabled_;
  Handle<JSObject> obj_;
};


MaybeHandle<JSObject> ConfigureInstance(Isolate* isolate, Handle<JSObject> obj,
                                        Handle<TemplateInfo> data) {
  auto property_list = handle(data->property_list(), isolate);
  if (property_list->IsUndefined()) return obj;
  // TODO(dcarney): just use a FixedArray here.
  NeanderArray properties(property_list);
  if (properties.length() == 0) return obj;
  HandleScope scope(isolate);
  // Disable access checks while instantiating the object.
  AccessCheckDisableScope access_check_scope(isolate, obj);
  for (int i = 0; i < properties.length();) {
    int length = Smi::cast(properties.get(i))->value();
    if (length == 3) {
      auto name = handle(Name::cast(properties.get(i + 1)), isolate);
      auto prop_data = handle(properties.get(i + 2), isolate);
      auto attributes = Smi::cast(properties.get(i + 3));
      RETURN_ON_EXCEPTION(isolate, DefineDataProperty(isolate, obj, name,
                                                      prop_data, attributes),
                          JSObject);
    } else {
      DCHECK(length == 4);
      auto name = handle(Name::cast(properties.get(i + 1)), isolate);
      auto getter = handle(properties.get(i + 2), isolate);
      auto setter = handle(properties.get(i + 3), isolate);
      auto attributes = Smi::cast(properties.get(i + 4));
      RETURN_ON_EXCEPTION(isolate,
                          DefineAccessorProperty(isolate, obj, name, getter,
                                                 setter, attributes),
                          JSObject);
    }
    i += length + 1;
  }
  return obj;
}


MaybeHandle<JSObject> InstantiateObject(Isolate* isolate,
                                        Handle<ObjectTemplateInfo> data) {
  // Enter a new scope.  Recursion could otherwise create a lot of handles.
  HandleScope scope(isolate);
  // Fast path.
  Handle<JSObject> result;
  auto info = Handle<ObjectTemplateInfo>::cast(data);
  auto constructor = handle(info->constructor(), isolate);
  Handle<JSFunction> cons;
  if (constructor->IsUndefined()) {
    cons = isolate->object_function();
  } else {
    auto cons_templ = Handle<FunctionTemplateInfo>::cast(constructor);
    ASSIGN_RETURN_ON_EXCEPTION(
        isolate, cons, InstantiateFunction(isolate, cons_templ), JSFunction);
  }
  auto object = isolate->factory()->NewJSObject(cons);
  ASSIGN_RETURN_ON_EXCEPTION(
      isolate, result, ConfigureInstance(isolate, object, info), JSFunction);
  // TODO(dcarney): is this necessary?
  JSObject::MigrateSlowToFast(result, 0, "ApiNatives::InstantiateObject");
  return scope.CloseAndEscape(result);
}


void CacheFunction(Isolate* isolate, Handle<Smi> serial_number,
                   Handle<JSFunction> function) {
  auto cache = isolate->function_cache();
  auto new_cache = ObjectHashTable::Put(cache, serial_number, function);
  isolate->native_context()->set_function_cache(*new_cache);
}


void UncacheFunction(Isolate* isolate, Handle<Smi> serial_number) {
  auto cache = isolate->function_cache();
  bool was_present = false;
  auto new_cache = ObjectHashTable::Remove(cache, serial_number, &was_present);
  DCHECK(was_present);
  isolate->native_context()->set_function_cache(*new_cache);
}


MaybeHandle<JSFunction> InstantiateFunction(Isolate* isolate,
                                            Handle<FunctionTemplateInfo> data,
                                            Handle<Name> name) {
  auto serial_number = handle(Smi::cast(data->serial_number()), isolate);
  // Probe cache.
  if (!data->do_not_cache()) {
    auto cache = isolate->function_cache();
    Object* element = cache->Lookup(serial_number);
    if (element->IsJSFunction()) {
      return handle(JSFunction::cast(element), isolate);
    }
  }
  // Enter a new scope.  Recursion could otherwise create a lot of handles.
  HandleScope scope(isolate);
  Handle<JSObject> prototype;
  if (!data->remove_prototype()) {
    auto prototype_templ = handle(data->prototype_template(), isolate);
    if (prototype_templ->IsUndefined()) {
      prototype = isolate->factory()->NewJSObject(isolate->object_function());
    } else {
      ASSIGN_RETURN_ON_EXCEPTION(
          isolate, prototype,
          InstantiateObject(isolate,
                            Handle<ObjectTemplateInfo>::cast(prototype_templ)),
          JSFunction);
    }
    auto parent = handle(data->parent_template(), isolate);
    if (!parent->IsUndefined()) {
      Handle<JSFunction> parent_instance;
      ASSIGN_RETURN_ON_EXCEPTION(
          isolate, parent_instance,
          InstantiateFunction(isolate,
                              Handle<FunctionTemplateInfo>::cast(parent)),
          JSFunction);
      // TODO(dcarney): decide what to do here.
      Handle<Object> parent_prototype;
      ASSIGN_RETURN_ON_EXCEPTION(
          isolate, parent_prototype,
          JSObject::GetProperty(parent_instance,
                                isolate->factory()->prototype_string()),
          JSFunction);
      RETURN_ON_EXCEPTION(
          isolate, JSObject::SetPrototype(prototype, parent_prototype, false),
          JSFunction);
    }
  }
  auto function = ApiNatives::CreateApiFunction(
      isolate, data, prototype, ApiNatives::JavaScriptObjectType);
  if (!name.is_null() && name->IsString()) {
    function->shared()->set_name(*name);
  }
  if (!data->do_not_cache()) {
    // Cache the function.
    CacheFunction(isolate, serial_number, function);
  }
  auto result = ConfigureInstance(isolate, function, data);
  if (result.is_null()) {
    // Uncache on error.
    if (!data->do_not_cache()) {
      UncacheFunction(isolate, serial_number);
    }
    return MaybeHandle<JSFunction>();
  }
  return scope.CloseAndEscape(function);
}


class InvokeScope {
 public:
  explicit InvokeScope(Isolate* isolate)
      : isolate_(isolate), save_context_(isolate) {}
  ~InvokeScope() {
    bool has_exception = isolate_->has_pending_exception();
    if (has_exception) {
      isolate_->ReportPendingMessages();
    } else {
      isolate_->clear_pending_message();
    }
  }

 private:
  Isolate* isolate_;
  SaveContext save_context_;
};


void AddPropertyToPropertyList(Isolate* isolate, Handle<TemplateInfo> templ,
                               int length, Handle<Object>* data) {
  auto list = handle(templ->property_list(), isolate);
  if (list->IsUndefined()) {
    list = NeanderArray(isolate).value();
    templ->set_property_list(*list);
  }
  NeanderArray array(list);
  array.add(isolate, isolate->factory()->NewNumberFromInt(length));
  for (int i = 0; i < length; i++) {
    Handle<Object> value =
        data[i].is_null()
            ? Handle<Object>::cast(isolate->factory()->undefined_value())
            : data[i];
    array.add(isolate, value);
  }
}

}  // namespace


MaybeHandle<JSFunction> ApiNatives::InstantiateFunction(
    Handle<FunctionTemplateInfo> data) {
  Isolate* isolate = data->GetIsolate();
  InvokeScope invoke_scope(isolate);
  return ::v8::internal::InstantiateFunction(isolate, data);
}


MaybeHandle<JSObject> ApiNatives::InstantiateObject(
    Handle<ObjectTemplateInfo> data) {
  Isolate* isolate = data->GetIsolate();
  InvokeScope invoke_scope(isolate);
  return ::v8::internal::InstantiateObject(isolate, data);
}


MaybeHandle<FunctionTemplateInfo> ApiNatives::ConfigureInstance(
    Isolate* isolate, Handle<FunctionTemplateInfo> desc,
    Handle<JSObject> instance) {
  // Configure the instance by adding the properties specified by the
  // instance template.
  if (desc->instance_template()->IsUndefined()) return desc;
  InvokeScope invoke_scope(isolate);
  Handle<ObjectTemplateInfo> instance_template(
      ObjectTemplateInfo::cast(desc->instance_template()), isolate);
  RETURN_ON_EXCEPTION(isolate, ::v8::internal::ConfigureInstance(
                                   isolate, instance, instance_template),
                      FunctionTemplateInfo);
  return desc;
}


void ApiNatives::AddDataProperty(Isolate* isolate, Handle<TemplateInfo> info,
                                 Handle<Name> name, Handle<Object> value,
                                 PropertyAttributes attributes) {
  const int kSize = 3;
  DCHECK(Smi::IsValid(static_cast<int>(attributes)));
  auto attribute_handle =
      handle(Smi::FromInt(static_cast<int>(attributes)), isolate);
  Handle<Object> data[kSize] = {name, value, attribute_handle};
  AddPropertyToPropertyList(isolate, info, kSize, data);
}


void ApiNatives::AddAccessorProperty(Isolate* isolate,
                                     Handle<TemplateInfo> info,
                                     Handle<Name> name,
                                     Handle<FunctionTemplateInfo> getter,
                                     Handle<FunctionTemplateInfo> setter,
                                     PropertyAttributes attributes) {
  const int kSize = 4;
  DCHECK(Smi::IsValid(static_cast<int>(attributes)));
  auto attribute_handle =
      handle(Smi::FromInt(static_cast<int>(attributes)), isolate);
  Handle<Object> data[kSize] = {name, getter, setter, attribute_handle};
  AddPropertyToPropertyList(isolate, info, kSize, data);
}


void ApiNatives::AddNativeDataProperty(Isolate* isolate,
                                       Handle<TemplateInfo> info,
                                       Handle<AccessorInfo> property) {
  auto list = handle(info->property_accessors(), isolate);
  if (list->IsUndefined()) {
    list = NeanderArray(isolate).value();
    info->set_property_accessors(*list);
  }
  NeanderArray array(list);
  array.add(isolate, property);
}


Handle<JSFunction> ApiNatives::CreateApiFunction(
    Isolate* isolate, Handle<FunctionTemplateInfo> obj,
    Handle<Object> prototype, ApiInstanceType instance_type) {
  Handle<Code> code = isolate->builtins()->HandleApiCall();
  Handle<Code> construct_stub = isolate->builtins()->JSConstructStubApi();

  obj->set_instantiated(true);
  Handle<JSFunction> result;
  if (obj->remove_prototype()) {
    result = isolate->factory()->NewFunctionWithoutPrototype(
        isolate->factory()->empty_string(), code);
  } else {
    int internal_field_count = 0;
    if (!obj->instance_template()->IsUndefined()) {
      Handle<ObjectTemplateInfo> instance_template = Handle<ObjectTemplateInfo>(
          ObjectTemplateInfo::cast(obj->instance_template()));
      internal_field_count =
          Smi::cast(instance_template->internal_field_count())->value();
    }

    // TODO(svenpanne) Kill ApiInstanceType and refactor things by generalizing
    // JSObject::GetHeaderSize.
    int instance_size = kPointerSize * internal_field_count;
    InstanceType type;
    switch (instance_type) {
      case JavaScriptObjectType:
        type = JS_OBJECT_TYPE;
        instance_size += JSObject::kHeaderSize;
        break;
      case GlobalObjectType:
        type = JS_GLOBAL_OBJECT_TYPE;
        instance_size += JSGlobalObject::kSize;
        break;
      case GlobalProxyType:
        type = JS_GLOBAL_PROXY_TYPE;
        instance_size += JSGlobalProxy::kSize;
        break;
      default:
        UNREACHABLE();
        type = JS_OBJECT_TYPE;  // Keep the compiler happy.
        break;
    }

    result = isolate->factory()->NewFunction(
        isolate->factory()->empty_string(), code, prototype, type,
        instance_size, obj->read_only_prototype(), true);
  }

  result->shared()->set_length(obj->length());
  Handle<Object> class_name(obj->class_name(), isolate);
  if (class_name->IsString()) {
    result->shared()->set_instance_class_name(*class_name);
    result->shared()->set_name(*class_name);
  }
  result->shared()->set_function_data(*obj);
  result->shared()->set_construct_stub(*construct_stub);
  result->shared()->DontAdaptArguments();

  if (obj->remove_prototype()) {
    DCHECK(result->shared()->IsApiFunction());
    DCHECK(!result->has_initial_map());
    DCHECK(!result->has_prototype());
    return result;
  }

#ifdef DEBUG
  LookupIterator it(handle(JSObject::cast(result->prototype())),
                    isolate->factory()->constructor_string(),
                    LookupIterator::OWN_SKIP_INTERCEPTOR);
  MaybeHandle<Object> maybe_prop = Object::GetProperty(&it);
  DCHECK(it.IsFound());
  DCHECK(maybe_prop.ToHandleChecked().is_identical_to(result));
#endif

  // Down from here is only valid for API functions that can be used as a
  // constructor (don't set the "remove prototype" flag).

  Handle<Map> map(result->initial_map());

  // Mark as undetectable if needed.
  if (obj->undetectable()) {
    map->set_is_undetectable();
  }

  // Mark as hidden for the __proto__ accessor if needed.
  if (obj->hidden_prototype()) {
    map->set_is_hidden_prototype();
  }

  // Mark as needs_access_check if needed.
  if (obj->needs_access_check()) {
    map->set_is_access_check_needed(true);
  }

  // Set interceptor information in the map.
  if (!obj->named_property_handler()->IsUndefined()) {
    map->set_has_named_interceptor();
  }
  if (!obj->indexed_property_handler()->IsUndefined()) {
    map->set_has_indexed_interceptor();
  }

  // Set instance call-as-function information in the map.
  if (!obj->instance_call_handler()->IsUndefined()) {
    map->set_has_instance_call_handler();
  }

  // Recursively copy parent instance templates' accessors,
  // 'data' may be modified.
  int max_number_of_additional_properties = 0;
  int max_number_of_static_properties = 0;
  FunctionTemplateInfo* info = *obj;
  while (true) {
    if (!info->instance_template()->IsUndefined()) {
      Object* props = ObjectTemplateInfo::cast(info->instance_template())
                          ->property_accessors();
      if (!props->IsUndefined()) {
        Handle<Object> props_handle(props, isolate);
        NeanderArray props_array(props_handle);
        max_number_of_additional_properties += props_array.length();
      }
    }
    if (!info->property_accessors()->IsUndefined()) {
      Object* props = info->property_accessors();
      if (!props->IsUndefined()) {
        Handle<Object> props_handle(props, isolate);
        NeanderArray props_array(props_handle);
        max_number_of_static_properties += props_array.length();
      }
    }
    Object* parent = info->parent_template();
    if (parent->IsUndefined()) break;
    info = FunctionTemplateInfo::cast(parent);
  }

  Map::EnsureDescriptorSlack(map, max_number_of_additional_properties);

  // Use a temporary FixedArray to acculumate static accessors
  int valid_descriptors = 0;
  Handle<FixedArray> array;
  if (max_number_of_static_properties > 0) {
    array = isolate->factory()->NewFixedArray(max_number_of_static_properties);
  }

  while (true) {
    // Install instance descriptors
    if (!obj->instance_template()->IsUndefined()) {
      Handle<ObjectTemplateInfo> instance = Handle<ObjectTemplateInfo>(
          ObjectTemplateInfo::cast(obj->instance_template()), isolate);
      Handle<Object> props =
          Handle<Object>(instance->property_accessors(), isolate);
      if (!props->IsUndefined()) {
        Map::AppendCallbackDescriptors(map, props);
      }
    }
    // Accumulate static accessors
    if (!obj->property_accessors()->IsUndefined()) {
      Handle<Object> props = Handle<Object>(obj->property_accessors(), isolate);
      valid_descriptors =
          AccessorInfo::AppendUnique(props, array, valid_descriptors);
    }
    // Climb parent chain
    Handle<Object> parent = Handle<Object>(obj->parent_template(), isolate);
    if (parent->IsUndefined()) break;
    obj = Handle<FunctionTemplateInfo>::cast(parent);
  }

  // Install accumulated static accessors
  for (int i = 0; i < valid_descriptors; i++) {
    Handle<AccessorInfo> accessor(AccessorInfo::cast(array->get(i)));
    JSObject::SetAccessor(result, accessor).Assert();
  }

  DCHECK(result->shared()->IsApiFunction());
  return result;
}

}  // namespace internal
}  // namespace v8