chromium/third_party/grpc/src/src/core/lib/promise/if.h

// Copyright 2021 gRPC authors.
//
// 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 GRPC_SRC_CORE_LIB_PROMISE_IF_H
#define GRPC_SRC_CORE_LIB_PROMISE_IF_H

#include <grpc/support/port_platform.h>

#include <type_traits>

#include "absl/status/statusor.h"
#include "absl/types/variant.h"

#include "src/core/lib/gprpp/construct_destruct.h"
#include "src/core/lib/promise/detail/promise_factory.h"
#include "src/core/lib/promise/detail/promise_like.h"
#include "src/core/lib/promise/poll.h"

namespace grpc_core {

namespace promise_detail {

template <typename CallPoll, typename T, typename F>
typename CallPoll::PollResult ChooseIf(CallPoll call_poll, bool result,
                                       T* if_true, F* if_false) { … }

template <typename CallPoll, typename T, typename F>
typename CallPoll::PollResult ChooseIf(CallPoll call_poll,
                                       absl::StatusOr<bool> result, T* if_true,
                                       F* if_false) { … }

template <typename C, typename T, typename F>
class If { … };

If<bool, T, F>;

}  // namespace promise_detail

// If promise combinator.
// Takes 3 promise factories, and evaluates the first.
// If it returns failure, returns failure for the entire combinator.
// If it returns true, evaluates the second promise.
// If it returns false, evaluates the third promise.
template <typename C, typename T, typename F>
promise_detail::If<C, T, F> If(C condition, T if_true, F if_false) { … }

}  // namespace grpc_core

#endif  // GRPC_SRC_CORE_LIB_PROMISE_IF_H