Files
nearby/internal/platform/future.h
T
2023-01-06 02:53:57 -08:00

55 lines
1.8 KiB
C++

// Copyright 2020 Google LLC
//
// 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
//
// https://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 PLATFORM_PUBLIC_FUTURE_H_
#define PLATFORM_PUBLIC_FUTURE_H_
#include "internal/platform/settable_future.h"
namespace nearby {
template <typename T>
class Future final {
public:
virtual bool Set(T value) { return impl_->Set(std::move(value)); }
virtual bool SetException(Exception exception) {
return impl_->SetException(exception);
}
virtual ExceptionOr<T> Get() { return impl_->Get(); }
virtual ExceptionOr<T> Get(absl::Duration timeout) {
return impl_->Get(timeout);
}
void AddListener(Runnable runnable, api::Executor* executor) {
impl_->AddListener(std::move(runnable), executor);
}
bool IsSet() const { return impl_->IsSet(); }
private:
// Instance of future implementation is wrapped in shared_ptr<> to make
// it possible to pass Future by value and share the implementation.
// This allows for the following constructions:
// 1)
// Future<bool> future;
// RunOnXyzThread([future]() { future.Set(DoTheJobAndReport()); });
// if (future.Get().Ok()) { /*...*/ }
// 2)
// Future<bool> future = DoSomeAsyncWork(); // Returns future, but keeps copy.
// if (future.Get().Ok()) { /*...*/ }
std::shared_ptr<SettableFuture<T>> impl_{new SettableFuture<T>()};
};
} // namespace nearby
#endif // PLATFORM_PUBLIC_FUTURE_H_