/*
* Copyright Onix Solutions Limited [OnixS]. All rights reserved.
*
* This software owned by Onix Solutions Limited [OnixS] and is protected by copyright law
* and international copyright treaties.
*
* Access to and use of the software is governed by the terms of the applicable OnixS Software
* Services Agreement (the Agreement) and Customer end user license agreements granting
* a non-assignable, non-transferable and non-exclusive license to use the software
* for it's own data processing purposes under the terms defined in the Agreement.
*
* Except as otherwise granted within the terms of the Agreement, copying or reproduction of any part
* of this source code or associated reference material to any other location for further reproduction
* or redistribution, and any amendments to this copyright notice, are expressly prohibited.
*
* Any reproduction or redistribution for sale or hiring of the Software not in accordance with
* the terms of the Agreement is a violation of copyright law.
*/

#pragma once

#include <OnixS/FIXEngine/ABI.h>
#include <OnixS/FIXEngine/Threading/Definitions.h>

namespace OnixS {
namespace Threading {

struct ThreadSafeQueueResult
{
    enum Enum
    {
        /// No data during the timeout.
        Timeout,

        /// We get data immediately or after waiting during the timeout.
        Data,

        // We don't get data but was signaled to stop wait.
        Signaled
    };
};

/// The thread-safe queue to send data from some thread(s) to another single thread.
/// The thread-safe queue owns enqueued elements and deallocates element's memory on the destruction.
class ONIXS_FIXENGINE_API ThreadSafeQueue
{
public:

    /// Initializes the instance.
    ThreadSafeQueue();

    /// Cleans up enqueued elements and internal resources.
    ~ThreadSafeQueue();

    /// Adds an item to the queue.
    /// Takes the ownership of the item from the smart pointer.
    ///
    /// @throw The DomainException if the smart pointer is null.
    ///
    /// @param enqueueItem The smart pointer to the allocated item to enqueue.
    void enqueue(ItemBaseUniquePtr & enqueueItem);

    /// Tries to get an item from the queue during the timeout.
    /// Gives the ownership of the item to the smart pointer.
    /// Returns the `ThreadSafeQueueResult` value which reflects the result status ('Timeout', 'Data', 'Signaled').
    ///
    /// @param dequeueItem The smart pointer to store the dequeued item.
    /// @param waitInMs The waiting timeout.
    ThreadSafeQueueResult::Enum dequeue(ItemBaseUniquePtr & dequeueItem, const int waitInMs = InfiniteTimeout);

    /// Removes all elements from the queue.
    void clear();

    /// Returns 'true' if the queue is empty, otherwise 'false'.
    bool empty() const;

    /// Wakes up the queue if it was in the waiting mode.
    /// The `dequeue` method will return the 'Signaled' status if it was in the waiting mode.
    void signal();

private:

    /// Implementation details.
    struct Impl;
    Impl * impl_;

    /// The copying and assignment are prohibited.
    ThreadSafeQueue(const ThreadSafeQueue &);
    ThreadSafeQueue & operator = (const ThreadSafeQueue &);
};

}
}