WeakRecordSB.h

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/*  Copyright (C) 2003-2021 Free Electron Organization
    Any use of this software requires a license.  If a valid license
    was not distributed with this file, visit freeelectron.org. */

/** @file */

#ifndef __data_WeakRecordSB_h__
#define __data_WeakRecordSB_h__

namespace fe
{

/** @brief Non-persistent reference to an instance of a Layout

    @ingroup data
*/
class FE_DL_EXPORT WeakRecordSB
{
    friend class RecordArraySB;
    public:
                    WeakRecordSB(I32 ignored=0);
//                  WeakRecordSB(void *datablock);
                    WeakRecordSB(const RecordSB &other);
                    WeakRecordSB(const WeakRecordSB &other);
virtual             ~WeakRecordSB(void);

                    operator RecordSB(void);

        WeakRecordSB    &operator=(const WeakRecordSB &other);

        bool        operator==(const WeakRecordSB &other) const;
        bool        operator!=(const WeakRecordSB &other) const;

                    /** @brief Return true if the record points to the
                        original valid state block

                        A record without the ":SN" field can never
                        be confirmed as valid.
                        You may be able access it if you are sure it
                        still exists by other means. */
        bool        isValid(void) const;
                    /** Set the state block. */
        void        set(void *datablock);
                    /** Return the state block. */
        FE_UWORD        idr(void) const;
                    /** Return the Layout. */
        const sp<LayoutSB>  &layout(void) const;


                    /** @brief throw if the record doesn't have
                        a serial number */
        void        demandSerialNumber(void) const;

        template <class T>
        T           &accessAttribute(FE_UWORD aLocator) const;

        void        *rawAttribute(FE_UWORD aLocator) const;

    private:
        void        *data(void) const;
                    /** Return a raw pointer to the Layout.
                        Mainly intended for Accessor for speed. */
        LayoutSB    *rawLayout(void) const;

    private:

        void        cacheSerialNumber(void);
        I32         readSerialNumber(void) const;

        sp<LayoutSB>    m_spLayout;
        void*           m_pStateBlock;
        I32             m_serialNumber;
        U32             m_serialOffset;
};

class WeakRecordSBInfo : public BaseType::Info
{
    public:
virtual String  print(void *instance);
virtual IWORD   output(std::ostream &ostrm, void *instance, t_serialMode mode);
virtual void    input(std::istream &istrm, void *instance, t_serialMode mode);
virtual IWORD   iosize(void);
virtual bool    getConstruct(void);
virtual void    construct(void *instance);
virtual void    destruct(void *instance);
};

inline WeakRecordSB::WeakRecordSB(I32):
    m_pStateBlock(NULL),
    m_serialNumber(-1)
{
}

inline WeakRecordSB::WeakRecordSB(const RecordSB& other)
{
    if(other.isValid())
    {
        m_spLayout = other.layout();
        m_pStateBlock = other.data();

        cacheSerialNumber();
    }
    else
    {
        m_pStateBlock=NULL;
        m_serialNumber= -1;
    }
}

inline WeakRecordSB::WeakRecordSB(const WeakRecordSB &other)
{
    if(other.isValid())
    {
        m_spLayout = other.m_spLayout;
        m_pStateBlock = other.m_pStateBlock;
        m_serialOffset = other.m_serialOffset;
        m_serialNumber = other.m_serialNumber;
    }
    else
    {
        m_pStateBlock=NULL;
        m_serialNumber= -1;
    }
}

/*
inline WeakRecordSB::WeakRecordSB(void *datablock)
{
    m_pStateBlock = datablock;
    m_spLayout = FE_SB_TO_HDR(m_pStateBlock)->m_pStore->getLayout();
}
*/

inline WeakRecordSB::~WeakRecordSB(void)
{
}

inline WeakRecordSB::operator RecordSB(void)
{
    RecordSB record;
    if(isValid())
    {
        record.set(m_pStateBlock);
    }
    return record;
}

inline I32 WeakRecordSB::readSerialNumber(void) const
{
    return (m_serialOffset==LayoutSB::offsetNone)?
        -1: *((I32 *)((char *)(m_pStateBlock) + m_serialOffset));
}

inline LayoutSB *WeakRecordSB::rawLayout(void) const
{
    return m_spLayout.raw();
}

inline WeakRecordSB &WeakRecordSB::operator=(const WeakRecordSB &other)
{
    if(this != &other)
    {
        m_spLayout = other.m_spLayout;
        m_pStateBlock = other.m_pStateBlock;
        m_serialOffset = other.m_serialOffset;
        m_serialNumber = other.m_serialNumber;
    }
    return *this;
}

inline bool WeakRecordSB::operator==(const WeakRecordSB &other) const
{
    return (m_pStateBlock == other.m_pStateBlock);
}

inline bool WeakRecordSB::operator!=(const WeakRecordSB &other) const
{
    return (m_pStateBlock != other.m_pStateBlock);
}

inline bool WeakRecordSB::isValid(void) const
{
    if(m_pStateBlock)
    {
        if(m_serialNumber<0 || m_serialNumber==readSerialNumber())
        {
            return TRUE;
        }

        const_cast<WeakRecordSB*>(this)->m_pStateBlock=NULL;
        const_cast<WeakRecordSB*>(this)->m_serialNumber= -1;
    }

    return FALSE;
}

inline void WeakRecordSB::set(void *datablock)
{
    m_pStateBlock = datablock;
    m_spLayout = FE_SB_TO_HDR(m_pStateBlock)->m_pStore->getLayout();

    // ???? Why were we making this record?
#ifdef FE_MAKE_RECORD_FOR_WEAKRECORD
    RecordSB record;
    record.set(datablock);
#endif
    cacheSerialNumber();

    //* reset if there is no serial number
#if TRUE
    if(isValid() && m_serialNumber<0)
    {
        feLog("WeakRecordSB::set layout \"%s\""
                " doesn't support \":SN\" attribute -> refusing assignment\n",
                m_spLayout->name().c_str());
        m_spLayout=NULL;
        m_pStateBlock=NULL;
    }
#endif
}

template <class T>
inline T &WeakRecordSB::accessAttribute(FE_UWORD aLocator) const
{
#if FE_CODEGEN<=FE_DEBUG
    return *((T *)((char *)(data()) + layout()->offsetTable()[aLocator]));
#else
    return *((T *)((char *)(data()) + rawLayout()->offsetTable()[aLocator]));
#endif
}

inline void *WeakRecordSB::rawAttribute(FE_UWORD aLocator) const
{
#if FE_CODEGEN<=FE_DEBUG
    return (void *)((char *)(data()) + layout()->offsetTable()[aLocator]);
#else
    return (void *)((char *)(data()) + rawLayout()->offsetTable()[aLocator]);
#endif
}

inline void *WeakRecordSB::data(void) const
{
    return m_pStateBlock;
}

inline FE_UWORD WeakRecordSB::idr(void) const
{
    return reinterpret_cast<FE_UWORD>(m_pStateBlock);
}

inline const sp<LayoutSB> &WeakRecordSB::layout(void) const
{
    return m_spLayout;
}

inline void WeakRecordSB::cacheSerialNumber(void)
{
    U32 index = m_spLayout->serialIndex();
    m_serialOffset = m_spLayout->offsetTable()[index];
    m_serialNumber = readSerialNumber();

#if FE_CODEGEN <= FE_DEBUG
    demandSerialNumber();
#endif
}


} /* namespace */

#endif /* __data_WeakRecordSB_h__ */