1 files changed, 402 insertions, 0 deletions
diff --git a/src/gvcore/cache.cpp b/src/gvcore/cache.cpp
new file mode 100644
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--- /dev/null
+++ b/src/gvcore/cache.cpp
@@ -0,0 +1,402 @@
+// vim: set tabstop=4 shiftwidth=4 noexpandtab
+/*
+Gwenview - A simple image viewer for KDE
+Copyright 2000-2004 Aurélien Gāteau
+ 
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License
+ as published by the Free Software Foundation; either version 2
+ of the License, or (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+*/
+
+#include "cache.h"
+
+// Qt
+
+// KDE
+#include <kconfig.h>
+#include <kdebug.h>
+#include <kdeversion.h>
+#include <ksharedptr.h>
+#include <kstaticdeleter.h>
+#include <kio/global.h>
+
+#include "cache.moc"
+
+namespace Gwenview {
+
+// Local
+
+#undef ENABLE_LOG
+#undef LOG
+//#define ENABLE_LOG
+#ifdef ENABLE_LOG
+#define LOG(x) kdDebug() << k_funcinfo << x << endl
+#else
+#define LOG(x) ;
+#endif
+
+//#define DEBUG_CACHE
+
+const char CONFIG_CACHE_MAXSIZE[]="maxSize";
+
+
+struct ImageData : public KShared {
+	ImageData( const KURL& url, const QDateTime& _timestamp )
+	: timestamp(_timestamp)
+	, age(0)
+	, fast_url( url.isLocalFile() && !KIO::probably_slow_mounted( url.path()))
+	, priority( false ) {
+	}
+
+	void addFile( const QByteArray& file );
+	void addImage( const ImageFrames& frames, const QCString& format );
+	void addThumbnail( const QPixmap& thumbnail, QSize imagesize );
+	long long cost() const;
+	int size() const;
+	QByteArray file;
+	ImageFrames frames;
+	QPixmap thumbnail;
+	QSize imagesize;
+	QCString format;
+	QDateTime timestamp;
+	mutable int age;
+	bool fast_url;
+	bool priority;
+	int fileSize() const;
+	int imageSize() const;
+	int thumbnailSize() const;
+	bool reduceSize();
+	bool isEmpty() const;
+
+	typedef KSharedPtr<ImageData> Ptr;
+};
+
+typedef QMap<KURL, ImageData::Ptr> ImageMap;
+
+struct Cache::Private {
+	ImageMap mImages;
+	int mMaxSize;
+	int mThumbnailSize;
+	QValueList< KURL > mPriorityURLs;
+
+
+	/**
+	 * This function tries to returns a valid ImageData for url and timestamp.
+	 * If it can't find one, it will create a new one and return it.
+	 */
+	ImageData::Ptr getOrCreateImageData(const KURL& url, const QDateTime& timestamp) {
+		if (mImages.contains(url)) {
+			ImageData::Ptr data = mImages[url];
+			if (data->timestamp == timestamp) return data;
+		}
+
+		ImageData::Ptr data = new ImageData(url, timestamp);
+		mImages[url] = data;
+		if (mPriorityURLs.contains(url)) data->priority = true;
+		return data;
+	}
+};
+
+
+Cache::Cache()
+{
+	d = new Private;
+	d->mMaxSize = DEFAULT_MAXSIZE;
+	// don't remember size for every thumbnail, but have one global and dump all if needed
+	d->mThumbnailSize = 0;
+}
+
+
+Cache::~Cache() {
+	d->mImages.clear();
+	delete d;
+}
+
+
+static Cache* sCache;
+static KStaticDeleter<Cache> sCacheDeleter;
+
+
+Cache* Cache::instance() {
+	if (!sCache) {
+		sCacheDeleter.setObject(sCache, new Cache());
+	}
+	return sCache;
+}
+
+// Priority URLs are used e.g. when prefetching for the slideshow - after an image is prefetched,
+// the loader tries to put the image in the cache. When the slideshow advances, the next loader
+// just gets the image from the cache. However, the prefetching may be useless if the image
+// actually doesn't stay long enough in the cache, e.g. because of being too big for the cache.
+// Marking an URL as a priority one will make sure it stays in the cache and that the cache
+// will be even enlarged as necessary if needed.
+void Cache::setPriorityURL( const KURL& url, bool set ) {
+	if( set ) {
+		d->mPriorityURLs.append( url );
+		if( d->mImages.contains( url )) {
+			d->mImages[ url ]->priority = true;
+		}
+	} else {
+		d->mPriorityURLs.remove( url );
+		if( d->mImages.contains( url )) {
+			d->mImages[ url ]->priority = false;
+		}
+		checkMaxSize();
+	}
+}
+
+
+void Cache::addFile( const KURL& url, const QByteArray& file, const QDateTime& timestamp ) {
+	LOG(url.prettyURL());
+	updateAge();
+	d->getOrCreateImageData(url, timestamp)->addFile(file);
+	checkMaxSize();
+}
+
+void Cache::addImage( const KURL& url, const ImageFrames& frames, const QCString& format, const QDateTime& timestamp ) {
+	LOG(url.prettyURL());
+	updateAge();
+	d->getOrCreateImageData(url, timestamp)->addImage(frames, format);
+	checkMaxSize();
+}
+
+void Cache::addThumbnail( const KURL& url, const QPixmap& thumbnail, QSize imagesize, const QDateTime& timestamp ) {
+// Thumbnails are many and often - things would age too quickly. Therefore
+// when adding thumbnails updateAge() is called from the outside only once for all of them.
+//	updateAge();
+	d->getOrCreateImageData(url, timestamp)->addThumbnail(thumbnail, imagesize);
+	checkMaxSize();
+}
+
+void Cache::invalidate( const KURL& url ) {
+	d->mImages.remove( url );
+}
+
+QDateTime Cache::timestamp( const KURL& url ) const {
+	LOG(url.prettyURL());
+	if( d->mImages.contains( url )) return d->mImages[ url ]->timestamp;
+	return QDateTime();
+}
+
+QByteArray Cache::file( const KURL& url ) const {
+	LOG(url.prettyURL());
+	if( d->mImages.contains( url )) {
+		const ImageData::Ptr data = d->mImages[ url ];
+		if( data->file.isNull()) return QByteArray();
+		data->age = 0;
+		return data->file;
+	}
+	return QByteArray();
+}
+
+void Cache::getFrames( const KURL& url, ImageFrames* frames, QCString* format ) const {
+	LOG(url.prettyURL());
+	Q_ASSERT(frames);
+	Q_ASSERT(format);
+	frames->clear();
+	*format = QCString();
+	if( d->mImages.contains( url )) {
+		const ImageData::Ptr data = d->mImages[ url ];
+		if( data->frames.isEmpty()) return;
+		*frames = data->frames;
+		*format = data->format;
+		data->age = 0;
+	}
+}
+
+QPixmap Cache::thumbnail( const KURL& url, QSize& imagesize ) const {
+	if( d->mImages.contains( url )) {
+		const ImageData::Ptr data = d->mImages[ url ];
+		if( data->thumbnail.isNull()) return QPixmap();
+		imagesize = data->imagesize;
+//		data.age = 0;
+		return data->thumbnail;
+	}
+	return QPixmap();
+}
+
+void Cache::updateAge() {
+	for( ImageMap::Iterator it = d->mImages.begin();
+		it != d->mImages.end();
+		++it ) {
+		(*it)->age++;
+	}
+}
+
+void Cache::checkThumbnailSize( int size ) {
+	if( size != d->mThumbnailSize ) {
+		// simply remove all thumbnails, should happen rarely
+		for( ImageMap::Iterator it = d->mImages.begin();
+			it != d->mImages.end();
+			) {
+			if( !(*it)->thumbnail.isNull()) {
+				ImageMap::Iterator it2 = it;
+				++it;
+				d->mImages.remove( it2 );
+			} else {
+				++it;
+			}
+		}
+		d->mThumbnailSize = size;
+	}
+}
+
+#ifdef DEBUG_CACHE
+static KURL _cache_url; // hack only for debugging for item to show also its key
+#endif
+
+void Cache::checkMaxSize() {
+	for(;;) {
+		int size = 0;
+		ImageMap::Iterator max;
+		long long max_cost = -1;
+#ifdef DEBUG_CACHE
+		int with_file = 0;
+		int with_thumb = 0;
+		int with_image = 0;
+#endif
+		for( ImageMap::Iterator it = d->mImages.begin();
+			it != d->mImages.end();
+			++it ) {
+			size += (*it)->size();
+#ifdef DEBUG_CACHE
+			if( !(*it).file.isNull()) ++with_file;
+			if( !(*it).thumbnail.isNull()) ++with_thumb;
+			if( !(*it).frames.isEmpty()) ++with_image;
+#endif
+			long long cost = (*it)->cost();
+			if( cost > max_cost && ! (*it)->priority ) {
+				max_cost = cost;
+				max = it;
+			}
+		}
+		if( size <= d->mMaxSize || max_cost == -1 ) {
+#if 0
+#ifdef DEBUG_CACHE
+			kdDebug() << "Cache: Statistics (" << d->mImages.size() << "/" << with_file << "/"
+				<< with_thumb << "/" << with_image << ")" << endl;
+#endif
+#endif
+			break;
+		}
+#ifdef DEBUG_CACHE
+		_cache_url = max.key();
+#endif
+
+		if( !(*max)->reduceSize() || (*max)->isEmpty()) d->mImages.remove( max );
+	}
+}
+
+void Cache::readConfig(KConfig* config,const QString& group) {
+	KConfigGroupSaver saver( config, group );
+	d->mMaxSize = config->readNumEntry( CONFIG_CACHE_MAXSIZE, d->mMaxSize );
+	checkMaxSize();
+}
+
+
+void ImageData::addFile( const QByteArray& f ) {
+	file = f;
+	file.detach(); // explicit sharing
+	age = 0;
+}
+
+void ImageData::addImage( const ImageFrames& fs, const QCString& f ) {
+	frames = fs;
+	format = f;
+	age = 0;
+}
+
+void ImageData::addThumbnail( const QPixmap& thumb, QSize imgsize ) {
+	thumbnail = thumb;
+	imagesize = imgsize;
+//	age = 0;
+}
+
+int ImageData::size() const {
+	return QMAX( fileSize() + imageSize() + thumbnailSize(), 100 ); // some minimal size per item
+}
+
+int ImageData::fileSize() const {
+	return !file.isNull() ? file.size() : 0;
+}
+
+int ImageData::thumbnailSize() const {
+	return !thumbnail.isNull() ? thumbnail.height() * thumbnail.width() * thumbnail.depth() / 8 : 0;
+}
+
+int ImageData::imageSize() const {
+	int ret = 0;
+	for( ImageFrames::ConstIterator it = frames.begin(); it != frames.end(); ++it ) {
+		ret += (*it).image.height() * (*it).image.width() * (*it).image.depth() / 8;
+	}
+	return ret;
+}
+
+bool ImageData::reduceSize() {
+	if( !file.isNull() && fast_url && !frames.isEmpty()) {
+		file = QByteArray();
+#ifdef DEBUG_CACHE
+		kdDebug() << "Cache: Dumping fast file: " << _cache_url.prettyURL() << ":" << cost() << endl;
+#endif
+		return true;
+	}
+	if( !thumbnail.isNull()) {
+#ifdef DEBUG_CACHE
+		kdDebug() << "Cache: Dumping thumbnail: " << _cache_url.prettyURL() << ":" << cost() << endl;
+#endif
+		thumbnail = QPixmap();
+		return true;
+	}
+	if( !file.isNull() && !frames.isEmpty()) {
+	// possibly slow file to fetch - dump the image data unless the image
+	// is JPEG (which needs raw data anyway) or the raw data much larger than the image
+		if( format == "JPEG" || fileSize() < imageSize() / 10 ) {
+			frames.clear();
+#ifdef DEBUG_CACHE
+			kdDebug() << "Cache: Dumping images: " << _cache_url.prettyURL() << ":" << cost() << endl;
+#endif
+		} else {
+			file = QByteArray();
+#ifdef DEBUG_CACHE
+			kdDebug() << "Cache: Dumping file: " << _cache_url.prettyURL() << ":" << cost() << endl;
+#endif
+		}
+		return true;
+	}
+#ifdef DEBUG_CACHE
+	kdDebug() << "Cache: Dumping completely: " << _cache_url.prettyURL() << ":" << cost() << endl;
+#endif
+	return false; // reducing here would mean clearing everything
+}
+
+bool ImageData::isEmpty() const {
+	return file.isNull() && frames.isEmpty() && thumbnail.isNull();
+}
+
+long long ImageData::cost() const {
+	long long s = size();
+	if( fast_url && !file.isNull()) {
+		s *= ( format == "JPEG" ? 10 : 100 ); // heavy penalty for storing local files
+	} else if( !thumbnail.isNull()) {
+		s *= 10 * 10; // thumbnails are small, and try to get rid of them soon
+	}
+	static const int mod[] = { 50, 30, 20, 16, 12, 10 };
+	if( age <= 5 ) {
+		return s * 10 / mod[ age ];
+	} else {
+		return s * ( age - 5 );
+	}
+}
+
+} // namespace