Future.h

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/*
* 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/ICE/BOE/ABI.h>
 
#include <exception>
 
namespace OnixS { namespace System { class FutureSharedState; }}
 
ONIXS_ICEBOE_NAMESPACE_BEGIN
namespace Threading {

struct FutureStatus
{
    enum Enum
    {
        ready,
        timeout,
        deferred
    };
};
 
namespace Implementation {
 
class FutureHelper;

class FutureBase
{
public:
    bool valid() const noexcept {
        return state_ != nullptr;
    }

    ONIXS_ICEBOE_EXPORTED bool is_ready() const;

    ONIXS_ICEBOE_EXPORTED bool has_value() const;

    ONIXS_ICEBOE_EXPORTED bool has_exception() const;

    ONIXS_ICEBOE_EXPORTED std::exception_ptr get_exception_ptr() const;
 
    enum { InfiniteTimeout = -1 };

    ONIXS_ICEBOE_EXPORTED FutureStatus::Enum wait(int timeoutInMs) const;
 
protected:
    FutureBase()
        : state_() {}
 
    ONIXS_ICEBOE_EXPORTED FutureBase(const FutureBase & other) noexcept;
 
    ONIXS_ICEBOE_EXPORTED FutureBase & operator=(const FutureBase & other) noexcept;
 
    ONIXS_ICEBOE_EXPORTED FutureBase(FutureBase && other) noexcept;
 
    ONIXS_ICEBOE_EXPORTED FutureBase & operator=(FutureBase && other) noexcept;
 
    struct moving_init_t {};

    ONIXS_ICEBOE_EXPORTED FutureBase(const System::FutureSharedState * state) noexcept;

    ONIXS_ICEBOE_EXPORTED FutureBase(const System::FutureSharedState * state, moving_init_t) noexcept;

    ONIXS_ICEBOE_EXPORTED ~FutureBase() noexcept;
 
    ONIXS_ICEBOE_EXPORTED void swap(FutureBase & other) noexcept;
 
    ONIXS_ICEBOE_EXPORTED const void * getValuePtr() const;
 
    ONIXS_ICEBOE_EXPORTED void getVoid() const;
 
private:
    const System::FutureSharedState * state_;
 
    friend class FutureHelper;
};
 
template<typename T>
struct FutureGetReturn {
    typedef const T & Type;
};
 
template<>
struct FutureGetReturn<void> {
    typedef void Type;
};
 
}

template <typename T>
class SharedFuture : public Implementation::FutureBase
{
public:
    SharedFuture() noexcept
        : FutureBase() {}

    SharedFuture(const SharedFuture<T> & other) noexcept
        : FutureBase(other) {}

    SharedFuture<T> & operator=(const SharedFuture<T> & other) noexcept {
        FutureBase::operator=(other);
        return *this;
    }
 
    SharedFuture(SharedFuture<T> && other) noexcept
        : FutureBase(std::move(other)) {}
 
    FutureBase & operator=(SharedFuture<T> && other) noexcept {
        FutureBase::operator=(std::move(other));
        return *this;
    }

    typename Implementation::FutureGetReturn<T>::Type get() const {
        return *reinterpret_cast<const T *>(getValuePtr());
    }

    void swap(SharedFuture<T> & other) noexcept {
        FutureBase::swap(other);
    }
 
private:
    SharedFuture(const System::FutureSharedState * state)
        : FutureBase(state) {}

    SharedFuture(const System::FutureSharedState * state, moving_init_t t) noexcept
        : FutureBase(state, t) {}
 
    friend class Implementation::FutureHelper;
};
 
template<>
inline void SharedFuture<void>::get() const {
    getVoid();
}
 
}
ONIXS_ICEBOE_NAMESPACE_END