CacheDigest.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.
 */
 
/* DEBUG: section 70    Cache Digest */
 
#ifndef SQUID_SRC_CACHEDIGEST_H
#define SQUID_SRC_CACHEDIGEST_H
 
#include "mem/forward.h"
#include "store_key_md5.h"
 
class CacheDigestGuessStats;
class StoreEntry;
 
class CacheDigest
{
    MEMPROXY_CLASS(CacheDigest);
public:
    CacheDigest(uint64_t capacity, uint8_t bpe);
    ~CacheDigest();
 
    // NP: only used by broken unit-test
    CacheDigest *clone() const;
 
    void clear();
 
    void updateCapacity(uint64_t newCapacity);
 
    void add(const cache_key * key);
    void remove(const cache_key * key);
 
    bool contains(const cache_key * key) const;
 
    double usedMaskPercent() const;
 
    static uint32_t CalcMaskSize(uint64_t cap, uint8_t bpe);
 
private:
    void init(uint64_t newCapacity);
 
public:
    /* public, read-only */
    uint64_t count;          /* number of digested entries */
    uint64_t del_count;      /* number of deletions performed so far */
    uint64_t capacity;       /* expected maximum for .count, not a hard limit */
    char *mask;              /* bit mask */
    uint32_t mask_size;      /* mask size in bytes */
    int8_t bits_per_entry;   /* number of bits allocated for each entry from capacity */
};
 
void cacheDigestGuessStatsUpdate(CacheDigestGuessStats * stats, int real_hit, int guess_hit);
void cacheDigestGuessStatsReport(const CacheDigestGuessStats * stats, StoreEntry * sentry, const SBuf &label);
void cacheDigestReport(CacheDigest * cd, const SBuf &label, StoreEntry * e);
 
#endif /* SQUID_SRC_CACHEDIGEST_H */