tsharedmemorykvs.h

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#pragma once
#include <QByteArray>
#include <QStringList>
#include <TGlobal>
#include <TKvsDatabase>
#include <TfNamespace>
 
struct hash_header_t;
class TSharedMemoryKvsDriver;
 
 
class T_CORE_EXPORT TSharedMemoryKvs {
public:
    class Bucket {
    public:
        QByteArray key;
        QByteArray value;
        qint64 expires {0};  // msecs since epoch
 
        bool isExpired() const
        {
            return expires <= Tf::getMSecsSinceEpoch();
        }
 
        void clear()
        {
            key.resize(0);
            value.resize(0);
            expires = 0;
        }
 
        friend QDataStream &operator<<(QDataStream &ds, const Bucket &bucket)
        {
            ds << bucket.key << bucket.value << bucket.expires;
            return ds;
        }
 
        friend QDataStream &operator>>(QDataStream &ds, Bucket &bucket)
        {
            ds >> bucket.key >> bucket.value >> bucket.expires;
            return ds;
        }
    };
 
    class T_CORE_EXPORT WriteLockingIterator {
    public:
        ~WriteLockingIterator();
        const QByteArray &key() const;
        const QByteArray &value() const;
        bool isExpired() const;
        const QByteArray &operator*() const;
        WriteLockingIterator &operator++();
        bool operator==(const WriteLockingIterator &other) const { return _hash == other._hash && _it == other._it; }
        bool operator!=(const WriteLockingIterator &other) const { return _hash != other._hash || _it != other._it; }
        void remove();
    private:
        WriteLockingIterator(TSharedMemoryKvs *hash, uint it);
        void search();
 
        TSharedMemoryKvs *_hash {nullptr};
        uint _it {0};
        bool _locked {false};
        Bucket _tmpbk;
        friend class TSharedMemoryKvs;
    };
 
    TSharedMemoryKvs();
    ~TSharedMemoryKvs();
 
    QByteArray get(const QByteArray &key);
    bool set(const QByteArray &key, const QByteArray &value, int seconds);
    bool remove(const QByteArray &key);
    uint count() const;
    uint tableSize() const;
    void clear();
    void gc();
    float loadFactor() const;
    void rehash();
    bool lockForRead();
    bool lockForWrite();
    bool unlock();
 
    WriteLockingIterator begin();
    WriteLockingIterator end();
 
    static bool initialize(const QString &name, const QString &options);  // only first time in system
    void cleanup();
 
protected:
    uint find(const QByteArray &key, Bucket &bucket) const;
    bool find(uint index, Bucket &bucket) const;
    int searchIndex(int first);
    uint index(const QByteArray &key) const;
    uint next(uint index) const;
    void remove(uint index);
 
 
private:
    TSharedMemoryKvs(Tf::KvsEngine engine);
    TSharedMemoryKvsDriver *driver();
    const TSharedMemoryKvsDriver *driver() const;
 
    TKvsDatabase _database;
    hash_header_t *_h {nullptr};
 
    friend class TCacheSharedMemoryStore;
    T_DISABLE_COPY(TSharedMemoryKvs)
    T_DISABLE_MOVE(TSharedMemoryKvs)
};