WriteBackCache.h++

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#ifndef __libquark_util_WriteBackCache_hxx
#define __libquark_util_WriteBackCache_hxx

#include <QHash>

namespace quark {
namespace util {

template<typename K, class T> class WriteBackCache
{
  public:

  virtual ~WriteBackCache();

  void insert(K key, T *value);

  T* lookup(K key);

  bool remove(K key);

  bool sync();

  bool flush();

  void setDirty(K key, bool dirty);

  bool isDirty(K key) const;

  protected:

  WriteBackCache(int maxCapacity);

  virtual void write(const T *value) = 0;

  private:

  struct Item
  {
    Item(K key, T *value)
      : key(key),
        value(value),
        dirty(false),
        next(NULL),
        prev(NULL)
    { }

    K key;
    T *value;
    bool dirty;
    struct Item *next;
    struct Item *prev;
  };

  void link(Item *item);
  void unlink(Item *item);
  bool iterate(bool doWrite, bool doDelete);

  int _maxCapacity;
  QHash<K, Item*> _map;
  Item *_head; // MRU
  Item *_tail;
};

#include <quark/WriteBackCacheImpl.h++>

} // namespace util
} // namespace quark

#endif // __libquark_util_WriteBackCache_hxx