Transients.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_TRANSIENTS_H
#define SQUID_SRC_TRANSIENTS_H
 
#include "ipc/mem/Page.h"
#include "ipc/mem/PageStack.h"
#include "ipc/StoreMap.h"
#include "Store.h"
#include "store/Controlled.h"
#include "store/forward.h"
#include <vector>
 
typedef Ipc::StoreMap TransientsMap;
 
class Transients: public Store::Controlled, public Ipc::StoreMapCleaner
{
public:
    class EntryStatus
    {
    public:
        bool hasWriter = false; 
        bool waitingToBeFreed = false; 
    };
 
    Transients();
    ~Transients() override;
 
    StoreEntry *findCollapsed(const sfileno xitIndex);
 
    void monitorIo(StoreEntry*, const cache_key*, const Store::IoStatus);
 
    void completeWriting(const StoreEntry &e);
 
    void status(const StoreEntry &e, EntryStatus &entryStatus) const;
 
    int readers(const StoreEntry &e) const;
 
    void disconnect(StoreEntry &);
 
    /* Store API */
    StoreEntry *get(const cache_key *) override;
    void create() override {}
    void init() override;
    uint64_t maxSize() const override;
    uint64_t minSize() const override;
    uint64_t currentSize() const override;
    uint64_t currentCount() const override;
    int64_t maxObjectSize() const override;
    void getStats(StoreInfoStats &stats) const override;
    void stat(StoreEntry &e) const override;
    void reference(StoreEntry &e) override;
    bool dereference(StoreEntry &e) override;
    void evictCached(StoreEntry &) override;
    void evictIfFound(const cache_key *) override;
    void maintain() override;
 
    bool markedForDeletion(const cache_key *) const;
 
    bool isReader(const StoreEntry &) const;
    bool isWriter(const StoreEntry &) const;
    bool hasWriter(const StoreEntry &);
 
    static int64_t EntryLimit();
 
    static bool Enabled() { return EntryLimit(); }
 
protected:
    void addEntry(StoreEntry*, const cache_key *, const Store::IoStatus);
    void addWriterEntry(StoreEntry &, const cache_key *);
    void addReaderEntry(StoreEntry &, const cache_key *);
 
    // Ipc::StoreMapCleaner API
    void noteFreeMapSlice(const Ipc::StoreMapSliceId sliceId) override;
 
private:
    TransientsMap *map;
 
    typedef std::vector<StoreEntry*> Locals;
    Locals *locals;
};
 
// TODO: Why use Store as a base? We are not really a cache.
 
#endif /* SQUID_SRC_TRANSIENTS_H */