SwapMetaView.h

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/*
 * Copyright (C) 1996-2025 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#ifndef SQUID_SRC_STORE_SWAPMETAVIEW_H
#define SQUID_SRC_STORE_SWAPMETAVIEW_H
 
#include "base/TextException.h"
#include "store/SwapMeta.h"
 
#include <iosfwd>
 
namespace Store {
 
class SwapMetaView
{
public:
    void checkExpectedLength(size_t) const;
 
public:
    const void *rawValue = nullptr;
 
    size_t rawLength = 0;
 
    RawSwapMetaType rawType = RawSwapMetaTypeBottom;
 
    SwapMetaType type = STORE_META_VOID;
 
private:
    /*
     * SwapMetaView objects should always be accessed through SwapMetaIterator
     * or SwapMetaUnpacker for read-only access to the current view of metadata.
     */
    friend class SwapMetaIterator;
 
    SwapMetaView() = default;
    SwapMetaView(const SwapMetaView &) = default;
    SwapMetaView(SwapMetaView &&) = default;
    SwapMetaView &operator =(const SwapMetaView &) = default;
    SwapMetaView &operator =(SwapMetaView &&) = default;
 
    explicit SwapMetaView(const void *begin, const void * const end);
};
 
template <typename Item>
void
SwapMetaExtract(Item &item, const char * &input, const void *end)
{
    if (input + sizeof(item) > end)
        throw TextException("truncated swap meta part", Here());
    memcpy(&item, input, sizeof(item));
    input += sizeof(item);
}
 
std::ostream &operator <<(std::ostream &, const SwapMetaView &);
 
} // namespace Store
 
#endif /* SQUID_SRC_STORE_SWAPMETAVIEW_H */