File indexing completed on 2025-01-05 03:59:34

 // SPDX-License-Identifier: LGPL-2.1-or-later
 //
 // SPDX-FileCopyrightText: 2007 Tobias Koenig <tokoe@kde.org>
 //
 
 
 // Own
 #include "DiscCache.h"
 
 // Qt
 #include <QtGlobal>
 #include <QFile>
 #include <QDirIterator>
 #include <QDataStream>
 
 #include "digikam_debug.h"
 
 using namespace Marble;
 
 static QString indexFileName( const QString &cacheDirectory )
 {
     return cacheDirectory + QLatin1String("/cache_index.idx");
 }
 
 DiscCache::DiscCache( const QString &cacheDirectory )
     : m_CacheDirectory( cacheDirectory ),
       m_CacheLimit( 300 * 1024 * 1024 ),
       m_CurrentCacheSize( 0 )
 {
     Q_ASSERT( !m_CacheDirectory.isEmpty() && "Passed empty cache directory!" );
 
     QFile file( indexFileName( m_CacheDirectory ) );
 
     if ( file.exists() ) {
         if ( file.open( QIODevice::ReadOnly ) ) {
             QDataStream s( &file );
             s.setVersion( 8 );
 
             s >> m_CacheLimit;
             s >> m_CurrentCacheSize;
             s >> m_Entries;
 
         } else {
             qCWarning(DIGIKAM_MARBLE_LOG) << QString::fromUtf8("Unable to open cache directory %s").arg(m_CacheDirectory);
         }
     }
 }
 
 DiscCache::~DiscCache()
 {
     QFile file( indexFileName( m_CacheDirectory ) );
 
     if ( file.open( QIODevice::WriteOnly ) ) {
         QDataStream s( &file );
         s.setVersion( 8 );
 
         s << m_CacheLimit;
         s << m_CurrentCacheSize;
         s << m_Entries;
     }
 
     file.close();
 }
 
 quint64 DiscCache::cacheLimit() const
 {
     return m_CacheLimit;
 }
 
 void DiscCache::clear()
 {
     QDirIterator it( m_CacheDirectory );
 
     // Remove all files from cache directory
     while ( it.hasNext() ) {
         it.next();
 
         if ( it.fileName() == indexFileName( m_CacheDirectory ) ) // skip index file
             continue;
 
         QFile::remove( it.fileName() );
     }
 
     // Delete entries
     m_Entries.clear();
 
     // Reset current cache size
     m_CurrentCacheSize = 0;
 }
 
 bool DiscCache::exists( const QString &key ) const
 {
     return m_Entries.contains( key );
 }
 
 bool DiscCache::find( const QString &key, QByteArray &data )
 {
     // Return error if we don't know this key
     if ( !m_Entries.contains( key ) )
         return false;
 
     // If we can open the file, load all data and update access timestamp
     QFile file( keyToFileName( key ) );
     if ( file.open( QIODevice::ReadOnly ) ) {
         data = file.readAll();
 
         m_Entries[ key ].first = QDateTime::currentDateTime();
         return true;
     }
 
     return false;
 }
 
 bool DiscCache::insert( const QString &key, const QByteArray &data )
 {
     // If we can't open/create a file for this entry signal an error
     QFile file( keyToFileName( key ) );
     if ( !file.open( QIODevice::WriteOnly ) )
         return false;
 
     // If we overwrite an existing entry, subtract the size first
     if ( m_Entries.contains( key ) )
         m_CurrentCacheSize -= m_Entries.value( key ).second;
 
     // Store the data on disc
     file.write( data );
 
     // Create/Overwrite with a new entry
     m_Entries.insert( key, QPair<QDateTime, quint64>(QDateTime::currentDateTime(), data.length()) );
 
     // Add the size of the new entry
     m_CurrentCacheSize += data.length();
 
     cleanup();
 
     return true;
 }
 
 void DiscCache::remove( const QString &key )
 {
     // Do nothing if we don't know the key
     if ( !m_Entries.contains( key ) )
         return;
 
     // If we can't remove the file we don't remove
     // the entry to prevent inconsistency
     if ( !QFile::remove( keyToFileName( key ) ) )
         return;
 
     // Subtract from current size
     m_CurrentCacheSize -= m_Entries.value( key ).second;
 
     // Finally remove entry
     m_Entries.remove( key );
 }
 
 void DiscCache::setCacheLimit( quint64 n )
 {
     m_CacheLimit = n;
 
     cleanup();
 }
 
 QString DiscCache::keyToFileName( const QString &key ) const
 {
     QString fileName( key );
     fileName.replace(QLatin1Char('/'), QLatin1Char('_'));
 
     return m_CacheDirectory + QLatin1Char('/') + fileName;
 }
 
 void DiscCache::cleanup()
 {
     // Calculate 5% of our current cache limit
     quint64 fivePercent = quint64( m_CacheLimit * 0.05 );
 
     while ( m_CurrentCacheSize > (m_CacheLimit - fivePercent) ) {
         QDateTime oldestDate( QDateTime::currentDateTime() );
         QString oldestKey;
 
         QMapIterator<QString, QPair<QDateTime, quint64> > it( m_Entries );
         while ( it.hasNext() ) {
             it.next();
 
             if ( it.value().first < oldestDate ) {
                 oldestDate = it.value().first;
                 oldestKey = it.key();
             }
         }
 
         if ( !oldestKey.isEmpty() ) {
             // We found the oldest key, so using remove() to
             // remove it from cache
             remove( oldestKey );
         }
     }
 }