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105 lines
2.6 KiB
C++
105 lines
2.6 KiB
C++
// Copyright 2024 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef PLATFORM_PUBLIC_ARRAY_BLOCKING_QUEUE_H_
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#define PLATFORM_PUBLIC_ARRAY_BLOCKING_QUEUE_H_
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#include <cstddef>
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#include <optional>
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#include <queue>
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#include "internal/platform/condition_variable.h"
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#include "internal/platform/logging.h"
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#include "internal/platform/mutex.h"
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#include "internal/platform/mutex_lock.h"
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namespace nearby {
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/**
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* Payload from different services/clients will be put into an
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* ArrayBlockingQueue before sending to ensure each client has equal chance to
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* send its data. Since C++ doesn't provide ArrayBlockingQueue as Java, we
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* implement one here.
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*/
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template <typename T>
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class ArrayBlockingQueue {
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public:
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explicit ArrayBlockingQueue(size_t capacity) : capacity_(capacity) {}
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void Put(const T& value) {
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MutexLock lock(&queue_mutex_);
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if (queue_.size() >= capacity_) {
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has_space_.Wait();
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}
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queue_.push(value);
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LOG(INFO) << "ArrayBlockingQueue::Put()";
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has_data_.Notify();
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}
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T Take() {
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MutexLock lock(&queue_mutex_);
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if (queue_.empty()) {
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has_data_.Wait();
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}
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T front = queue_.front();
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queue_.pop();
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LOG(INFO) << "ArrayBlockingQueue::Take()";
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has_space_.Notify();
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return front;
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}
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bool TryPut(const T& value) {
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MutexLock lock(&queue_mutex_);
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if (queue_.size() < capacity_) {
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queue_.push(value);
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has_data_.Notify();
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return true;
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}
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return false;
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}
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// Returns std::nullopt if the queue is empty.
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std::optional<T> TryTake() {
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MutexLock lock(&queue_mutex_);
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if (!queue_.empty()) {
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T front = queue_.front();
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queue_.pop();
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has_space_.Notify();
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return front;
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}
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return std::nullopt;
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}
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size_t Size() const {
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MutexLock lock(&queue_mutex_);
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return queue_.size();
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}
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bool Empty() const {
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MutexLock lock(&queue_mutex_);
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return queue_.empty();
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}
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private:
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std::queue<T> queue_;
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mutable Mutex queue_mutex_;
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ConditionVariable has_data_{&queue_mutex_};
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ConditionVariable has_space_{&queue_mutex_};
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const size_t capacity_;
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};
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} // namespace nearby
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#endif // PLATFORM_PUBLIC_ARRAY_BLOCKING_QUEUE_H_
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