Detailed Description
The QNetworkDiskCache class provides a very basic disk cache.
QNetworkDiskCache stores each url in its own file inside of the cacheDirectory using QDataStream. Files with a text MimeType are compressed using qCompress. Each cache file starts with "cache_" and ends in ".cache". Data is written to disk only in insert() and updateMetaData().
Currently you can not share the same cache files with more then one disk cache.
QNetworkDiskCache by default limits the amount of space that the cache will use on the system to 50MB.
Note you have to set the cache directory before it will work.
Member Function Documentation
QNetworkDiskCache::QNetworkDiskCache ( QObject * parent = 0 )
Creates a new disk cache. The parent argument is passed to QAbstractNetworkCache's constructor.
QNetworkDiskCache::~QNetworkDiskCache ()
Destroys the cache object. This does not clear the disk cache.
QString QNetworkDiskCache::cacheDirectory () const
Returns the location where cached files will be stored.
See also setCacheDirectory().
qint64 QNetworkDiskCache::expire () [virtual protected]
Cleans the cache so that its size is under the maximum cache size. Returns the current size of the cache.
When the current size of the cache is greater than the maximumCacheSize() older cache files are removed until the total size is less then 90% of maximumCacheSize() starting with the oldest ones first using the file creation date to determine how old a cache file is.
Subclasses can reimplement this function to change the order that cache files are removed taking into account information in the application knows about that QNetworkDiskCache does not, for example the number of times a cache is accessed.
Note: cacheSize() calls expire if the current cache size is unknown.
See also maximumCacheSize() and fileMetaData().
QNetworkCacheMetaData QNetworkDiskCache::fileMetaData ( const QString & fileName ) const
Returns the QNetworkCacheMetaData for the cache file fileName.
If fileName is not a cache file QNetworkCacheMetaData will be invalid.
qint64 QNetworkDiskCache::maximumCacheSize () const
Returns the current maximum size for the disk cache.
See also setMaximumCacheSize().
void QNetworkDiskCache::setCacheDirectory ( const QString & cacheDir )
Sets the directory where cached files will be stored to cacheDir
QNetworkDiskCache will create this directory if it does not exists.
Prepared cache items will be stored in the new cache directory when they are inserted.
See also cacheDirectory() and QDesktopServices::CacheLocation.
void QNetworkDiskCache::setMaximumCacheSize ( qint64 size )
Sets the maximum size of the disk cache to be size.
If the new size is smaller then the current cache size then the cache will call expire().
See also maximumCacheSize().
