/*
 * Copyright 2019-present Facebook, Inc.
 *
 * 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.
 */

#include <folly/experimental/coro/Materialize.h>

namespace folly {
namespace coro {

template <typename Reference, typename Value>
AsyncGenerator<Reference, Value> dematerialize(
    AsyncGenerator<CallbackRecord<Reference>, CallbackRecord<Value>> source) {
  while (auto item = co_await source.next()) {
    if (item->hasValue()) {
      // Value
      co_yield std::move(*item).value();
    } else if (item->hasNone()) {
      // None
      co_return;
    } else if (item->hasError()) {
      // Exception
      std::move(*item).error().throw_exception();
    } else {
      DCHECK(false);
      std::terminate();
    }
  }
}

} // namespace coro
} // namespace folly
