src/cobalt/script/javascriptcore/union_type_conversion_impl.h.pump

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$$ Maximum number of different member types in a union.
$var MAX_MEMBERS = 4
/*
 * Copyright 2015 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.
 */

#ifndef COBALT_SCRIPT_JAVASCRIPTCORE_UNION_TYPE_CONVERSION_IMPL_H_
#define COBALT_SCRIPT_JAVASCRIPTCORE_UNION_TYPE_CONVERSION_IMPL_H_

#include "cobalt/script/javascriptcore/jsc_global_object.h"
#include "cobalt/script/union_type.h"

// Conversion to/from JSC::JSValue for IDL union types.

namespace cobalt {
namespace script {
namespace javascriptcore {

$range NUM_MEMBERS 2..MAX_MEMBERS
$for NUM_MEMBERS [[

$range TYPE 1..NUM_MEMBERS

template <$for TYPE , [[typename T$(TYPE)]]>
JSC::JSValue ToJSValue(JSCGlobalObject* global_object,
                       const script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>& in_union) {
$for TYPE [[

  if (in_union.template IsType<T$(TYPE)>()) {
    return ToJSValue(global_object, in_union.template AsType<T$(TYPE)>());
  }
]]

  NOTREACHED();
  return JSC::jsUndefined();
}

template <$for TYPE , [[typename T$(TYPE)]]>
void FromJSValue(JSC::ExecState* exec_state, JSC::JSValue jsvalue,
                 int conversion_flags, ExceptionState* exception_state,
                 script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>* out_union) {
  DCHECK_EQ(0, conversion_flags);
  // JS -> IDL type conversion procedure described here:
  // http://heycam.github.io/webidl/#es-union

  // 1. If the union type includes a nullable type and V is null or undefined,
  // then return the IDL value null.
  if (jsvalue.isNull() || jsvalue.isUndefined()) {
    // If the type was nullable or undefined, we should have caught that as a
    // part of the base::optional<T> conversion.
    NOTREACHED();
    return;
  }
  // Typedef for readability.

$for TYPE [[
  typedef ::cobalt::script::internal::UnionTypeTraits<T$(TYPE)> UnionTypeTraitsT$(TYPE);

]]

  // Forward declare all potential types

$for TYPE [[
  T$(TYPE) t$(TYPE);

]]

  // 3.1 If types includes an interface type that V implements, then return the
  //     IDL value that is a reference to the object V.
  // 3.2 If types includes object, then return the IDL value that is a reference
  //     to the object V.
  //
  // The specification doesn't dictate what should happen if V implements more
  // than one of the interfaces. For example, if V implements interface B and
  // interface B inherits from interface A, what happens if both A and B are
  // union members? Blink doesn't seem to do anything special for this case.
  // Just choose the first interface in the flattened members that matches.
  if (jsvalue.isObject()) {
    JSCGlobalObject* global_object =
        JSC::jsCast<JSCGlobalObject*>(exec_state->lexicalGlobalObject());
    const WrapperFactory* wrapper_factory = global_object->wrapper_factory();
    JSC::JSCell* js_cell = jsvalue.asCell();


$for TYPE [[
    if (UnionTypeTraitsT$(TYPE)::is_interface_type &&
        js_cell->inherits(
            wrapper_factory->GetClassInfo(
                UnionTypeTraitsT$(TYPE)::GetTypeID()))) {
      FromJSValue(exec_state, jsvalue, conversion_flags, exception_state, &t$(TYPE));
      *out_union = script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>(t$(TYPE));
      return;
    }

]]
  }

  // TODO: Support Date, RegExp, DOMException, Error, ArrayBuffer, DataView,
  //       TypedArrayName, callback functions, dictionary, array type.
  //       And sequences if necessary.

  // 14. If V is a Boolean value, then:
  //   1. If types includes a boolean, then return the result of converting V
  //      to boolean.
  if (jsvalue.isBoolean()) {
$for TYPE [[

    if (UnionTypeTraitsT$(TYPE)::is_boolean_type) {
      FromJSValue(exec_state, jsvalue, conversion_flags, exception_state, &t$(TYPE));
      *out_union = script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>(t$(TYPE));
      return;
    }

]]
  }

  // 15. If V is a Number value, then:
  //   1. If types includes a numeric type, then return the result of converting
  //      V to that numeric type.
  if (jsvalue.isNumber()) {
$for TYPE [[

    if (UnionTypeTraitsT$(TYPE)::is_numeric_type) {
      FromJSValue(exec_state, jsvalue, conversion_flags, exception_state, &t$(TYPE));
      *out_union = script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>(t$(TYPE));
      return;
    }

]]
  }

  // 16. If types includes a string type, then return the result of converting V
  // to that type.
  if (jsvalue.isString()) {
$for TYPE [[

    if (UnionTypeTraitsT$(TYPE)::is_string_type) {
      FromJSValue(exec_state, jsvalue, conversion_flags, exception_state, &t$(TYPE));
      *out_union = script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>(t$(TYPE));
      return;
    }

]]
  }

  // 17. If types includes a numeric type, then return the result of converting
  // V to that numeric type.
$for TYPE [[

  if (UnionTypeTraitsT$(TYPE)::is_numeric_type) {
    FromJSValue(exec_state, jsvalue, conversion_flags, exception_state, &t$(TYPE));
    *out_union = script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>(t$(TYPE));
    return;
  }
]]


  // 18. If types includes a boolean, then return the result of converting V to
  // boolean.
$for TYPE [[

  if (UnionTypeTraitsT$(TYPE)::is_boolean_type) {
    FromJSValue(exec_state, jsvalue, conversion_flags, exception_state, &t$(TYPE));
    *out_union = script::UnionType$(NUM_MEMBERS)<$for TYPE , [[T$(TYPE)]]>(t$(TYPE));
    return;
  }
]]


  // 19. Throw a TypeError.
  exception_state->SetSimpleException(kNotUnionType);
}

]]  $$ for NUM_MEMBERS

}  // namespace javascriptcore
}  // namespace script
}  // namespace cobalt

#endif  // COBALT_SCRIPT_JAVASCRIPTCORE_UNION_TYPE_CONVERSION_IMPL_H_