pw_async2/future.cc

// Copyright 2026 The Pigweed 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
//
//     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.

#include "pw_async2/future.h"

#include <iterator>

#include "pw_assert/check.h"

namespace pw::async2 {

FutureCore::FutureCore(FutureCore&& other) noexcept
    : waker_(std::move(other.waker_)), state_(std::move(other.state_)) {
  if (!other.unlisted()) {
    this->replace(other);
  }
}

FutureCore& FutureCore::operator=(FutureCore&& other) noexcept {
  if (this == &other) {
    return *this;
  }

  Unlist();

  state_ = std::move(other.state_);
  waker_ = std::move(other.waker_);

  this->replace(other);
  return *this;
}

size_t BaseFutureList::size() const {
  return static_cast<size_t>(std::distance(list_.begin(), list_.end()));
}

void BaseFutureList::PushRequireEmpty(FutureCore& future) {
  PW_CHECK(list_.empty());
  Push(future);
}

bool BaseFutureList::PushIfEmpty(FutureCore& future) {
  if (list_.empty()) {
    Push(future);
    return true;
  }
  return false;
}

void BaseFutureList::ResolveAll() {
  while (!list_.empty()) {
    list_.front().WakeAndMarkReady();
    list_.pop_front();
  }
}

}  // namespace pw::async2