Digikam::LoadingCache Class Reference

Inheritance diagram for Digikam::LoadingCache:

Classes
class	CacheLock

Signals
void	fileChanged (const QString &filePath)
	This signal is emitted when the cache is notified that a file was changed.

Public Member Functions
void	addLoadingProcess (LoadingProcess *const process)
	Add a loading process to the list.
quint64	getCacheSize () const
	Get the cache size in bytes.
bool	hasThumbnailPixmap (const QString &cacheKey) const
bool	isCacheable (const DImg &img) const
void	notifyFileChanged (const QString &filePath, bool notify=true)
	Remove all entries from cache that were loaded from filePath.
void	notifyNewLoadingProcess (LoadingProcess *const process, const LoadingDescription &description)
	Notify all currently registered loading processes.
bool	putImage (const QString &cacheKey, const DImg &img, const QString &filePath) const
	Put image into for given string into the cache.
void	putThumbnail (const QString &cacheKey, const QImage &thumb, const QString &filePath)
	Puts a thumbnail into the thumbnail cache.
void	putThumbnail (const QString &cacheKey, const QPixmap &thumb, const QString &filePath)
void	removeImage (const QString &cacheKey)
	Remove entries for the given cacheKey from the cache.
void	removeImages ()
	Remove all entries from the cache.
void	removeLoadingProcess (LoadingProcess *const process)
	Remove loading process for given cache key.
void	removeThumbnail (const QString &cacheKey)
	Remove the thumbnail for the given file path from the thumbnail cache.
void	removeThumbnails ()
	Remove all thumbnails.
const QPixmap *	retrieveBufferedTPixmap (const QString &cacheKey) const
DImg *	retrieveImage (const QString &cacheKey) const
	Retrieves an image for the given string from the cache, or 0 if no image is found.
LoadingProcess *	retrieveLoadingProcess (const QString &cacheKey) const
	Find the loading process for given cacheKey, or 0 if not found.
const QImage *	retrieveThumbnail (const QString &cacheKey) const
	The LoadingCache support both the caching of QImage and QPixmap objects.
const QPixmap *	retrieveThumbnailPixmap (const QString &cacheKey) const
void	setCacheSize (int megabytes)
	Sets the cache size in megabytes.
void	setFileWatch (LoadingCacheFileWatch *const watch)
	Sets a LoadingCacheFileWatch to watch the files contained in this cache.
void	setThumbnailCacheSize (int numberOfQImages, int numberOfQPixmaps)
	Sets the size of the thumbnail cache.

Static Public Member Functions
static LoadingCache *	cache ()
static void	cleanUp ()

Friends
class	CacheLock
class	LoadingCacheFileWatch

Member Function Documentation

addLoadingProcess()

void Digikam::LoadingCache::addLoadingProcess

(

LoadingProcess *const

process

)

Only one loading process for the same cache key is registered at a time.

fileChanged

void Digikam::LoadingCache::fileChanged ( const QString & filePath )

signal

There is no information in this signal if the file was ever contained in the cache. The signal may be emitted under CacheLock. Strongly consider a queued connection.

isCacheable()

bool Digikam::LoadingCache::isCacheable

(

const DImg &

img

)

const

Returns

whether the given DImg fits in the cache.

notifyFileChanged()

void Digikam::LoadingCache::notifyFileChanged	(	const QString &	filePath,
		bool	notify = true )

Emits relevant signals if notify = true.

putImage()

bool Digikam::LoadingCache::putImage	(	const QString &	cacheKey,
		const DImg &	img,
		const QString &	filePath ) const

Returns

true if image has been put in the cache, false otherwise. Ownership of the DImg instance is passed to the cache. When it cannot be put in the cache it is deleted. The third parameter specifies a file path that will be watched. If this file changes, the object will be removed from the cache.

retrieveThumbnail()

const QImage * Digikam::LoadingCache::retrieveThumbnail

(

const QString &

cacheKey

)

const

QPixmaps can only be accessed from the main thread, so the tasks cannot access this cache.

Retrieves a thumbnail for the given filePath from the thumbnail cache, or a 0 if the thumbnail is not found.

setCacheSize()

void Digikam::LoadingCache::setCacheSize

(

int

megabytes

)

The thumbnail cache is not affected and setThumbnailCacheSize takes the maximum number.

setFileWatch()

void Digikam::LoadingCache::setFileWatch

(

LoadingCacheFileWatch *const

watch

)

Ownership of this object is transferred to the cache.

setThumbnailCacheSize()

void Digikam::LoadingCache::setThumbnailCacheSize	(	int	numberOfQImages,
		int	numberOfQPixmaps )

Parameters

numberOfQImages	The maximum number of thumbnails of max possible size in QImage format that will be cached. If the size of the images is smaller, a larger number will be cached.
numberOfQPixmaps	The maximum number of thumbnails of max possible size in QPixmap format that will be cached. If the size of the images is smaller, a larger number will be cached.

Note

: The main cache is unaffected by this method, and setCacheSize takes megabytes as parameter.

: A good caching strategy will be to set one of the numbers to 0. Default values: (0, 100)