// Copyright 2024 The NATS 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.

import NIOConcurrencyHelpers

internal class ConcurrentQueue<T> {
    private var elements: [T] = []
    private let lock = NIOLock()

    func enqueue(_ element: T) {
        lock.lock()
        defer { lock.unlock() }
        elements.append(element)
    }

    func dequeue() -> T? {
        lock.lock()
        defer { lock.unlock() }
        guard !elements.isEmpty else { return nil }
        return elements.removeFirst()
    }
}