FileDataCache.h

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//     ____   ______ __
//    / __ \ / ____// /
//   / /_/ // /    / /
//  / ____// /___ / /___   PixInsight Class Library
// /_/     \____//_____/   PCL 2.6.5
// ----------------------------------------------------------------------------
// pcl/FileDataCache.h - Released 2024-01-13T15:47:58Z
// ----------------------------------------------------------------------------
// This file is part of the PixInsight Class Library (PCL).
// PCL is a multiplatform C++ framework for development of PixInsight modules.
//
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// modification, is permitted provided that the following conditions are met:
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// ----------------------------------------------------------------------------
 
#ifndef __PCL_FileDataCache_h
#define __PCL_FileDataCache_h
 
 
#include <pcl/File.h>
#include <pcl/Matrix.h>
#include <pcl/MultiVector.h>
#include <pcl/Mutex.h>
#include <pcl/ReferenceSortedArray.h>
#include <pcl/StringList.h>
#include <pcl/TimePoint.h>
 
namespace pcl
{
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS FileDataCacheItem
{
public:
 
   String    path;     
   IsoString key;      
   TimePoint time;     
   TimePoint lastUsed; 
 
   virtual ~FileDataCacheItem()
   {
   }
 
   void Assign( const FileDataCacheItem& item )
   {
      path     = item.path;
      key      = item.key;
      time     = item.time;
      lastUsed = item.lastUsed;
   }
 
   bool operator ==( const FileDataCacheItem& item ) const
   {
      return path == item.path;
   }
 
   bool operator <( const FileDataCacheItem& item ) const
   {
      if ( path != item.path )
         return path < item.path;
      return key < item.key;
   }
 
   bool ModifiedSince( FileTime t ) const
   {
      t.milliseconds = 0;
      return time < TimePoint( t );
   }
 
   double DaysSinceLastUsed() const
   {
      return TimePoint::Now() - lastUsed;
   }
 
protected:
 
   virtual void AssignData( const FileDataCacheItem& item )
   {
   }
 
   virtual IsoStringList SerializedData() const
   {
      return IsoStringList();
   }
 
   virtual bool DeserializeData( const IsoStringList& tokens )
   {
      return true;
   }
 
   virtual bool ValidateData() const
   {
      return true;
   }
 
   static IsoStringList SerializedVector( const DVector& vector );
 
   static bool DeserializeVector( DVector& vector, IsoStringList::const_iterator& start, const IsoStringList& tokens );
 
   static IsoStringList SerializedMatrix( const DMatrix& matrix );
 
   static bool DeserializeMatrix( DMatrix& matrix, IsoStringList::const_iterator& start, const IsoStringList& tokens );
 
   static IsoStringList SerializedMultiVector( const DMultiVector& multivector );
 
   static bool DeserializeMultiVector( DMultiVector& multivector, IsoStringList::const_iterator& start, const IsoStringList& tokens );
 
   static IsoStringList SerializedMatrices( const Array<DMatrix>& matrices );
 
   static bool DeserializeMatrices( Array<DMatrix>& matrices, IsoStringList::const_iterator& start, const IsoStringList& tokens );
 
   FileDataCacheItem( const FileDataCacheItem& ) = default;
 
   FileDataCacheItem( const String& p = String(), const IsoString& k = IsoString() )
      : path( p )
      , key( k )
   {
   }
 
   friend class FileDataCache;
};
 
// ----------------------------------------------------------------------------
 
class PCL_CLASS FileDataCache
{
public:
 
   FileDataCache( const IsoString& identifier, int maxItemDuration = 30 );
 
   virtual ~FileDataCache()
   {
      Clear();
   }
 
   virtual String CacheName() const
   {
      return "File Cache";
   }
 
   virtual int Version() const
   {
      return 1;
   }
 
   virtual int MinSupportedVersion() const
   {
      return 1;
   }
 
   int MaxItemDuration() const
   {
      return m_maxItemDuration;
   }
 
   virtual void SetMaxItemDuration( int days )
   {
      m_maxItemDuration = Range( days, 0, 120 );
   }
 
   bool ItemsNeverExpire() const
   {
      return m_maxItemDuration <= 0;
   }
 
   IsoString TokenSeparator() const
   {
      return m_separator;
   }
 
   void SetTokenSeparator( const IsoString& separator )
   {
      m_separator = separator.IsEmpty() ? IsoString( '\n' ) : separator;
   }
 
   bool IsCompressionEnabled() const
   {
      return m_compressionEnabled;
   }
 
   void EnableCompression( bool enable = true )
   {
      m_compressionEnabled = enable;
   }
 
   void DisableCompression( bool disable = true )
   {
      EnableCompression( !disable );
   }
 
   size_type NumberOfItems() const;
 
   bool IsEmpty() const;
 
   fsize_type FileSize() const;
 
   const FileDataCacheItem* Find( const String& path, const IsoString& key = IsoString() ) const;
 
   void Clear();
 
   void Add( const FileDataCacheItem& item );
 
   bool Get( FileDataCacheItem& item, const String& path, const IsoString& key = IsoString() );
 
   int ModifiedCount() const
   {
      return m_modifiedCount;
   }
 
   bool IsModified() const
   {
      return m_modifiedCount > 0;
   }
 
   virtual void Load();
 
   virtual void Save() const;
 
   virtual void Purge() const;
 
protected:
 
   virtual FileDataCacheItem* NewItem() const = 0;
 
private:
 
   using cache_index = ReferenceSortedArray<FileDataCacheItem>;
 
   mutable Mutex       m_mutex;
           cache_index m_cache;
           IsoString   m_identifier;
           String      m_filePath;
           IsoString   m_separator = '\n';
           int         m_maxItemDuration = 30; // in days
           bool        m_compressionEnabled = true;
   mutable int         m_modifiedCount = 0;
};
 
// ----------------------------------------------------------------------------
 
} // pcl
 
#endif   // __PCL_FileDataCache_h
 
// ----------------------------------------------------------------------------
// EOF pcl/FileDataCache.h - Released 2024-01-13T15:47:58Z