future.h

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/*
 * Copyright 2019 GridGain Systems, Inc. and Contributors.
 *
 * Licensed under the GridGain Community Edition License (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.gridgain.com/products/software/community-edition/gridgain-community-edition-license
 *
 * 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.
 */
 
#ifndef _IGNITE_FUTURE
#define _IGNITE_FUTURE
 
#include <ignite/common/shared_state.h>
 
namespace ignite
{
    namespace common
    {
        // Forward declaration
        template<typename T>
        class Promise;
    }
    template<typename T>
    class Future
    {
        friend class common::Promise<T>;
 
    public:
        typedef T ValueType;
 
        Future(const Future<ValueType>& src) :
            state(src.state)
        {
            // No-op.
        }
 
        Future& operator=(const Future<ValueType>& other)
        {
            state = other.state;
 
            return *this;
        }
 
        void Wait() const
        {
            const common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->Wait();
        }
 
        bool WaitFor(int32_t msTimeout) const
        {
            const common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->WaitFor(msTimeout);
        }
 
        const ValueType& GetValue() const
        {
            const common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->GetValue();
        }
 
        void Cancel()
        {
            common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->Cancel();
        }
 
        bool IsReady()
        {
            common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->IsSet();
        }
 
    private:
        Future(common::concurrent::SharedPointer< common::SharedState<ValueType> > state0) :
            state(state0)
        {
            // No-op.
        }
 
        common::concurrent::SharedPointer< common::SharedState<ValueType> > state;
    };
 
    template<>
    class Future<void>
    {
        friend class common::Promise<void>;
 
    public:
        typedef void ValueType;
 
        Future(const Future<ValueType>& src) :
            state(src.state)
        {
            // No-op.
        }
 
        Future& operator=(const Future<ValueType>& other)
        {
            state = other.state;
 
            return *this;
        }
 
        void Wait() const
        {
            const common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->Wait();
        }
 
        bool WaitFor(int32_t msTimeout) const
        {
            const common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->WaitFor(msTimeout);
        }
 
        void GetValue() const
        {
            const common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->GetValue();
        }
 
        void Cancel()
        {
            common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->Cancel();
        }
 
        bool IsReady()
        {
            common::SharedState<ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->IsSet();
        }
 
    private:
        Future(common::concurrent::SharedPointer< common::SharedState<ValueType> > state0) :
            state(state0)
        {
            // No-op.
        }
 
        common::concurrent::SharedPointer< common::SharedState<ValueType> > state;
    };
 
    template<typename T>
    class Future< common::concurrent::SharedPointer<T> >
    {
        friend class common::Promise< common::concurrent::SharedPointer<T> >;
 
    public:
        typedef T ValueType;
 
        typedef common::concurrent::SharedPointer<ValueType> SP_ValueType;
 
        Future(const Future<SP_ValueType>& src) :
            state(src.state)
        {
            // No-op.
        }
 
        Future& operator=(const Future<SP_ValueType>& other)
        {
            if (this != &other)
                state = other.state;
 
            return *this;
        }
 
        void Wait() const
        {
            const common::SharedState<SP_ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->Wait();
        }
 
        bool WaitFor(int32_t msTimeout) const
        {
            const common::SharedState<SP_ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->WaitFor(msTimeout);
        }
 
        SP_ValueType GetValue() const
        {
            const common::SharedState<SP_ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->GetValue();
        }
 
        void Cancel()
        {
            common::SharedState<SP_ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            state0->Cancel();
        }
 
        bool IsReady()
        {
            common::SharedState<SP_ValueType>* state0 = state.Get();
 
            assert(state0 != 0);
 
            return state0->IsSet();
        }
 
    private:
        Future(common::concurrent::SharedPointer< common::SharedState<SP_ValueType> > state0) :
            state(state0)
        {
            // No-op.
        }
 
        common::concurrent::SharedPointer< common::SharedState<SP_ValueType> > state;
    };
}
 
#endif //_IGNITE_FUTURE