src/cobalt/bindings/javascriptcore/templates/interface-object.template

{#
 # Copyright 2016 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #}

{% macro create_interface_object(interface_object_class_name, interface_object_name) -%}
// Class that defines a JS Object representing this interface's Interface Object
// https://www.w3.org/TR/WebIDL/#interface-object
class {{binding_class}}::{{interface_object_class_name}} : public ConstructorBase {
 public:
  // Get the Interface Object. Will create a new Interface Object if necessary,
  // otherwise it will return the cached one.
  static JSC::JSObject* GetInstance(JSC::ExecState* exec);
  DECLARE_CLASSINFO();

  // Needed when JSC::OverridesGetOwnPropertySlot StructureFlag is set
  // Must be public so that it can be accessible from getStaticValueSlot<>.
  static bool getOwnPropertySlot(JSC::JSCell* cell, JSC::ExecState* exec,
                                 JSC::PropertyName property_name,
                                 JSC::PropertySlot& slot) {
    {{interface_object_class_name}}* this_object = JSC::jsCast<{{interface_object_class_name}}*>(cell);
    ASSERT_GC_OBJECT_INHERITS(this_object, &s_info);

    // Same process as JSC::getStaticPropertySlot<>, which is defined in Lookup.h
    // Since JSFunction::getOwnPropertySlot is protected, we can't call it from
    // the helper function.
    const JSC::HashEntry* entry =
        GetPropertyTable(exec)->entry(exec, property_name);

    if (!entry) // not found, forward to parent
      return Base::getOwnPropertySlot(this_object, exec, property_name, slot);

    if (entry->attributes() & JSC::Function)
        return setUpStaticFunctionSlot(exec, entry, this_object, property_name, slot);

    slot.setCacheableCustom(this_object, entry->propertyGetter());
    return true;
  }

  // static override. Needed to support setting a property.
  static void put(JSC::JSCell* cell, JSC::ExecState* exec_state,
                  JSC::PropertyName property_name, JSC::JSValue value,
                  JSC::PutPropertySlot& slot) {
    {{interface_object_class_name}}* this_object = JSC::jsCast<{{interface_object_class_name}}*>(cell);
    ASSERT_GC_OBJECT_INHERITS(this_object, &s_info);
    bool found_property = JSC::lookupPut<{{interface_object_class_name}}>(
        exec_state, property_name, value, GetPropertyTable(exec_state),
        this_object, slot.isStrictMode());
    DLOG_IF(INFO, !found_property) << "Did not find property named " <<
        WTF::String(property_name.publicName()).utf8().data() <<
        " to set on interface object for {{binding_class}}";
    if (!found_property) {
      BaseClass::put(cell, exec_state, property_name, value, slot);
    }
  }

  // static override. This prevents this object from being called as a normal
  // function, throwing a TypeError if the user attempts to do so.
  static JSC::CallType getCallData(JSC::JSCell*, JSC::CallData&) {
    return JSC::CallTypeNone;
  }

{% if not constructor %}
  // static override. This prevents this object from being called as a
  // constructor, throwing a TypeError if the user attempts to do so.
  //
  // This method is defined when no constructors are defined on the IDL.
  static JSC::ConstructType getConstructData(JSC::JSCell*, JSC::ConstructData&) {
    return JSC::ConstructTypeNone;
  }
{% endif %}

 private:
  typedef ConstructorBase BaseClass;

  static const unsigned StructureFlags =
      JSC::ImplementsHasInstance |
      JSC::OverridesGetOwnPropertySlot |
      BaseClass::StructureFlags;

  {{interface_object_class_name}}(JSC::ExecState* exec_state, JSC::JSGlobalObject* global_object, JSC::Structure* structure)
      : BaseClass(exec_state, global_object, structure) { }
  void finishCreation(JSC::ExecState* exec_state,
                      JSC::NativeExecutable* native_executable, int length,
                      const String& name);

  static const JSC::HashTable* GetPropertyTable(JSC::ExecState* exec_state);

  static const JSC::HashTableValue property_table_values[];
  static const JSC::HashTable property_table_prototype;
};

const JSC::HashTableValue {{binding_class}}::{{interface_object_class_name}}::property_table_values[] = {
    // static functions will also go here.
{% for attribute in static_attributes %}
{% if attribute.conditional %}
#if defined({{attribute.conditional}})
{% endif %}
    { "{{attribute.idl_name}}",
        JSC::DontDelete {{'| JSC::ReadOnly' if attribute.is_read_only}},
        reinterpret_cast<intptr_t>(getJS{{attribute.idl_name}}),
        {% if attribute.is_read_only %}
        0,
        {% else %}
        reinterpret_cast<intptr_t>(setJS{{attribute.idl_name}}),
        {% endif %}
        JSC::NoIntrinsic
    },
{% if attribute.conditional %}
#endif  // defined({{attribute.conditional}})
{% endif %}
{% endfor %}
{% for operation in static_operations %}
{% if operation.conditional %}
#if defined({{operation.conditional}})
{% endif %}
    { "{{operation.idl_name}}",
        JSC::DontDelete | JSC::Function,
        reinterpret_cast<intptr_t>(staticFunctionJS{{operation.idl_name}}),
        static_cast<intptr_t>({{operation.length}}),
        JSC::NoIntrinsic
    },
{% if operation.conditional %}
#endif  // defined({{operation.conditional}})
{% endif %}
{% endfor %}
{% for constant in constants %}
    { "{{constant.idl_name}}",
        JSC::DontDelete | JSC::ReadOnly,
        reinterpret_cast<intptr_t>(getJS{{constant.idl_name}}),
        0,
        JSC::NoIntrinsic
    },
{% endfor %}
    { 0, 0, 0, 0, static_cast<JSC::Intrinsic>(0) }
};  // {{binding_class}}::{{interface_object_class_name}}::property_table_values

// static
const JSC::HashTable
{{binding_class}}::{{interface_object_class_name}}::property_table_prototype = {
{% set num_properties = constants|length + static_attributes|length + static_operations|length %}
    // Sizes will be calculated based on the number of static functions as well.
    {{ calculate_jsc_lookup_size(num_properties) }},  // compactSize
    {{ calculate_jsc_lookup_size_mask(num_properties) }},  // compactSizeMask
    property_table_values,
    NULL  // table allocated at runtime
};  // {{binding_class}}::{{interface_object_class_name}}::property_table_prototype

// static
const JSC::HashTable*
{{binding_class}}::{{interface_object_class_name}}::GetPropertyTable(
    JSC::ExecState* exec_state) {
  return ThreadLocalHashTable::GetInstance()->GetHashTable(
      {{binding_class}}::{{interface_object_class_name}}::s_classinfo(),
      property_table_prototype);
}

const JSC::ClassInfo {{binding_class}}::{{interface_object_class_name}}::s_info = {
    "{{interface_name}}Constructor",  // className
    BaseClass::s_classinfo(),  // parentClass
    NULL,  // static hash-table of properties (not used)
    GetPropertyTable,  // function pointer to get hash-table of properties
    CREATE_METHOD_TABLE({{binding_class}}::{{interface_object_class_name}})
};  // {{binding_class}}::{{interface_object_class_name}}::s_info

void {{binding_class}}::{{interface_object_class_name}}::finishCreation(
    JSC::ExecState* exec_state, JSC::NativeExecutable* native_executable,
    int length, const String& name) {
  BaseClass::finishCreation(exec_state, native_executable, length, name);
  ASSERT(inherits(&s_info));
  // Add a 'prototype' property whose value is the prototype object.
  putDirect(exec_state->globalData(),
            exec_state->propertyNames().prototype,
            {{binding_class}}::GetPrototype(exec_state->lexicalGlobalObject()),
            JSC::DontDelete | JSC::ReadOnly | JSC::DontEnum);
  DCHECK(hasOwnProperty(exec_state, JSC::Identifier(exec_state, "prototype")));
}

// static
JSC::JSObject* {{binding_class}}::{{interface_object_class_name}}::GetInstance(
    JSC::ExecState* exec_state) {
  JSCGlobalObject* global_object =
      static_cast<JSCGlobalObject*>(exec_state->lexicalGlobalObject());
  ASSERT_GC_OBJECT_INHERITS(global_object, JSCGlobalObject::s_classinfo());

  // Try to get the cached interface object, and create a new one if needed.
  JSC::JSObject* interface_object = global_object->object_cache()->GetCachedConstructor(&s_info);
  if (interface_object == NULL) {
    JSC::JSGlobalData& global_data = global_object->globalData();
    JSC::JSObject* parent_prototype = global_object->functionPrototype();
    JSC::TypeInfo type_info(JSC::ObjectType, StructureFlags);
    JSC::Structure* structure = JSC::Structure::create(
        global_data,
        global_object,
        JSC::JSValue(parent_prototype),
        type_info,
        &s_info);

{% if constructor %}
    const int kNumArguments = {{constructor.length}};
    JSC::NativeExecutable* executable = global_data.getHostFunction(NULL, &constructorJS{{impl_class}});
{% else %}
    const int kNumArguments = 0;
    // NativeExecutable must be non-null even if this is not actually callable.
    JSC::NativeExecutable* executable = global_data.getHostFunction(NULL, NULL);
{% endif %}

    // Create the new interface object.
    {{interface_object_class_name}}* new_interface_object =
        new (NotNull, JSC::allocateCell<{{interface_object_class_name}}>(global_data.heap))
        {{interface_object_class_name}}(exec_state, global_object, structure);
    new_interface_object->finishCreation(exec_state, executable, kNumArguments, "{{interface_object_name}}");
    // Add the interface object to the cache.
    global_object->object_cache()->CacheConstructor(&s_info, new_interface_object);
    interface_object = new_interface_object;
  }
  DCHECK_EQ(global_object->object_cache()->GetCachedConstructor(&s_info), interface_object);
  return interface_object;
}

// End of {{binding_class}}::{{interface_object_class_name}} class
{% endmacro %}