CancellationToken.h

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/*--------------------------------------------------------------------------------------+
|
|   Supplied under applicable software license agreement.
|
|   Copyright (c) 2018 Bentley Systems, Incorporated. All rights reserved.
|
+---------------------------------------------------------------------------------------*/
#pragma once


#include <functional>
#include <atomic>
#if !defined (BENTLEY_CONFIG_NO_THREAD_SUPPORT)
#   include <thread>
#endif
#include <Bentley/Tasks/Tasks.h>
#include <Bentley/bvector.h>

BEGIN_BENTLEY_TASKS_NAMESPACE

/*--------------------------------------------------------------------------------------+
* @bsiclass                                                     Bentley Systems
+---------------+---------------+---------------+---------------+---------------+------*/
struct ICancellationListener
    {
    virtual ~ICancellationListener() {};
    virtual void OnCanceled() = 0;
    };

/*--------------------------------------------------------------------------------------+
* @bsiclass                                                     Bentley Systems
+---------------+---------------+---------------+---------------+---------------+------*/
struct SimpleCancellationListener : ICancellationListener
    {
    private:
        std::function<void ()> m_onCanceled;

    public:
        BENTLEYDLL_EXPORT SimpleCancellationListener(std::function<void ()> onCanceled);
        BENTLEYDLL_EXPORT virtual ~SimpleCancellationListener();
        BENTLEYDLL_EXPORT virtual void OnCanceled() override;
    };

/*--------------------------------------------------------------------------------------+
* @bsiclass                                                     Bentley Systems
+---------------+---------------+---------------+---------------+---------------+------*/
typedef std::shared_ptr<struct ICancellationToken> ICancellationTokenPtr;
struct ICancellationToken
    {
    virtual ~ICancellationToken() {};
    virtual bool IsCanceled() = 0;
    virtual void Register(std::weak_ptr<ICancellationListener> listener) = 0;
    };

/*--------------------------------------------------------------------------------------+
* @bsiclass                                                     Bentley Systems
+---------------+---------------+---------------+---------------+---------------+------*/
typedef std::shared_ptr<struct SimpleCancellationToken> SimpleCancellationTokenPtr;
struct EXPORT_VTABLE_ATTRIBUTE SimpleCancellationToken : ICancellationToken
    {
    private:
        BeAtomic<bool> m_canceled;
        bvector<std::weak_ptr<ICancellationListener>> m_listeners;

    private:
        void OnCancelled() const;

    public:
        explicit SimpleCancellationToken(bool canceled) : m_canceled(canceled) {};
        virtual ~SimpleCancellationToken() {};

        BENTLEYDLL_EXPORT static SimpleCancellationTokenPtr Create(bool canceled = false);

        BENTLEYDLL_EXPORT virtual bool IsCanceled() override;
        BENTLEYDLL_EXPORT virtual void SetCanceled();
        BENTLEYDLL_EXPORT virtual void Register(std::weak_ptr<ICancellationListener> listener) override;
    };

/*--------------------------------------------------------------------------------------+
* @bsiclass                                                     Bentley Systems
+---------------+---------------+---------------+---------------+---------------+------*/
typedef std::shared_ptr<struct MergeCancellationToken> MergeCancellationTokenPtr;
struct MergeCancellationToken : ICancellationToken
    {
    private:
        bvector <ICancellationTokenPtr> m_tokens;

    public:
        MergeCancellationToken(const bvector<ICancellationTokenPtr>& tokens);
        virtual ~MergeCancellationToken();

        BENTLEYDLL_EXPORT static MergeCancellationTokenPtr Create(const bvector<ICancellationTokenPtr>& tokens);
        BENTLEYDLL_EXPORT static MergeCancellationTokenPtr Create (ICancellationTokenPtr ct1, ICancellationTokenPtr ct2);
        
        BENTLEYDLL_EXPORT virtual bool IsCanceled() override;
        BENTLEYDLL_EXPORT virtual void Register(std::weak_ptr<ICancellationListener> listener) override;
    };

END_BENTLEY_TASKS_NAMESPACE