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 *   Licensed to the Apache Software Foundation (ASF) under one or more
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#ifndef INCLUDED_FRAMEWORK_INC_THREADHELP_IRWLOCK_H
#define INCLUDED_FRAMEWORK_INC_THREADHELP_IRWLOCK_H

namespace framework{

/*-************************************************************************************************************//**
    @descr          A guard (specialy a write guard) support different internal working states.
                    His lock can set for reading or writing/reading! Or he was unlocked by user ...
*//*-*************************************************************************************************************/
enum ELockMode
{
    E_NOLOCK    ,
    E_READLOCK  ,
    E_WRITELOCK
};

/*-************************************************************************************************************//**
    @descr          We implement two guards for using an rw-lock. But if you wish to implement
                    different rw-locks to you will have problems by using with same guard implementation!
                    Thats why we define this "pure virtual base class" ...
                    All rw-locks must support this base interface for working and all guard must use this one too!
*//*-*************************************************************************************************************/
class IRWLock
{
    //-------------------------------------------------------------------------------------------------------------
    //  public methods
    //-------------------------------------------------------------------------------------------------------------
    public:

        /*-****************************************************************************************************//**
            @descr      These functions must be supported by a derived class!
                            acquireReadAccess()     -try to register thread as reader
                            releaseReadAccess()     -unregister thread as reader
                            acquireWriteAccess()    -try to register thread as writer
                            releaseWriteAccess()    -unregister thread as writer
                            downgradeWriteAccess()  -make writer to reader
        *//*-*****************************************************************************************************/
        virtual void acquireReadAccess    () =0;
        virtual void releaseReadAccess    () =0;
        virtual void acquireWriteAccess   () =0;
        virtual void releaseWriteAccess   () =0;
        virtual void downgradeWriteAccess () =0;

    protected:
        ~IRWLock() {}
};      //  class IRWLock

}       //  namespace framework

#endif // INCLUDED_FRAMEWORK_INC_THREADHELP_IRWLOCK_H

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