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diff --git a/digikam/libs/threadimageio/loadingcache.h b/digikam/libs/threadimageio/loadingcache.h
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+/* ============================================================
+ *
+ * This file is a part of digiKam project
+ * http://www.digikam.org
+ *
+ * Date        : 2006-01-11
+ * Description : shared image loading and caching
+ *
+ * Copyright (C) 2005-2007 by Marcel Wiesweg <marcel.wiesweg@gmx.de>
+ *
+ * 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, 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.
+ *
+ * ============================================================ */
+
+#ifndef LOADING_CACHE_H
+#define LOADING_CACHE_H
+
+#include <qptrlist.h>
+#include <qcache.h>
+#include <qdict.h>
+#include <qmutex.h>
+
+#include "dimg.h"
+#include "loadsavethread.h"
+
+namespace Digikam
+{
+
+class LoadingProcessListener
+{
+public:
+
+    virtual bool querySendNotifyEvent() = 0;
+    virtual QObject *eventReceiver() = 0;
+    virtual LoadSaveThread::AccessMode accessMode() = 0;
+
+};
+
+class LoadingProcess
+{
+public:
+
+    virtual bool completed() = 0;
+    virtual QString filePath() = 0;
+    virtual QString cacheKey() = 0;
+    virtual void addListener(LoadingProcessListener *listener) = 0;
+    virtual void removeListener(LoadingProcessListener *listener) = 0;
+    virtual void notifyNewLoadingProcess(LoadingProcess *process, LoadingDescription description) = 0;
+
+};
+
+class LoadingCachePriv;
+
+class LoadingCache : public QObject
+{
+
+    Q_OBJECT
+
+public:
+
+    static LoadingCache *cache();
+    static void cleanUp();
+    ~LoadingCache();
+
+    // all functions shall only be called when a CacheLock is held
+    class CacheLock
+    {
+    public:
+        CacheLock(LoadingCache *cache);
+        ~CacheLock();
+        void wakeAll();
+        void timedWait();
+    private:
+        LoadingCache *m_cache;
+    };
+
+    // Retrieves an image for the given string from the cache,
+    // or 0 if no image is found.
+    DImg *retrieveImage(const QString &cacheKey);
+    // Returns whether the given DImg fits in the cache.
+    bool isCacheable(const DImg *img);
+    // Put image into for given string into the cache.
+    // 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.
+    bool putImage(const QString &cacheKey, DImg *img, const QString &filePath);
+    void removeImage(const QString &cacheKey);
+    void removeImages();
+
+    // Find the loading process for given cacheKey, or 0 if not found
+    LoadingProcess *retrieveLoadingProcess(const QString &cacheKey);
+    // Add a loading process to the list. Only one loading process
+    // for the same cache key is registered at a time.
+    void addLoadingProcess(LoadingProcess *process);
+    // Remove loading process for given cache key
+    void removeLoadingProcess(LoadingProcess *process);
+    // Notify all currently registered loading processes
+    void notifyNewLoadingProcess(LoadingProcess *process, LoadingDescription description);
+
+    void setCacheSize(int megabytes);
+
+protected:
+
+    virtual void customEvent (QCustomEvent *event);
+
+private slots:
+
+    void slotFileDirty(const QString &path);
+
+private:
+
+    static LoadingCache *m_instance;
+
+    LoadingCache();
+
+    friend class CacheLock;
+    LoadingCachePriv *d;
+
+};
+
+}   // namespace Digikam
+
+#endif