- clean working copy for leaving SVN

2022-06-28 19:04:46 +02:00
parent 62a2d47cb3
commit 762b8f0e7d
1966 changed files with 699872 additions and 126 deletions
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+/*
+  ==============================================================================
+
+   This file is part of the JUCE library.
+   Copyright (c) 2013 - Raw Material Software Ltd.
+
+   Permission is granted to use this software under the terms of either:
+   a) the GPL v2 (or any later version)
+   b) the Affero GPL v3
+
+   Details of these licenses can be found at: www.gnu.org/licenses
+
+   JUCE 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.
+
+   ------------------------------------------------------------------------------
+
+   To release a closed-source product which uses JUCE, commercial licenses are
+   available: visit www.juce.com for more information.
+
+  ==============================================================================
+*/
+
+#ifndef JUCE_AUDIOTHUMBNAILCACHE_H_INCLUDED
+#define JUCE_AUDIOTHUMBNAILCACHE_H_INCLUDED
+
+
+//==============================================================================
+/**
+    An instance of this class is used to manage multiple AudioThumbnail objects.
+
+    The cache runs a single background thread that is shared by all the thumbnails
+    that need it, and it maintains a set of low-res previews in memory, to avoid
+    having to re-scan audio files too often.
+
+    @see AudioThumbnail
+*/
+class JUCE_API  AudioThumbnailCache
+{
+public:
+    //==============================================================================
+    /** Creates a cache object.
+
+        The maxNumThumbsToStore parameter lets you specify how many previews should
+        be kept in memory at once.
+    */
+    explicit AudioThumbnailCache (int maxNumThumbsToStore);
+
+    /** Destructor. */
+    virtual ~AudioThumbnailCache();
+
+    //==============================================================================
+    /** Clears out any stored thumbnails. */
+    void clear();
+
+    /** Reloads the specified thumb if this cache contains the appropriate stored
+        data.
+
+        This is called automatically by the AudioThumbnail class, so you shouldn't
+        normally need to call it directly.
+    */
+    bool loadThumb (AudioThumbnailBase& thumb, int64 hashCode);
+
+    /** Stores the cachable data from the specified thumb in this cache.
+
+        This is called automatically by the AudioThumbnail class, so you shouldn't
+        normally need to call it directly.
+    */
+    void storeThumb (const AudioThumbnailBase& thumb, int64 hashCode);
+
+    /** Tells the cache to forget about the thumb with the given hashcode. */
+    void removeThumb (int64 hashCode);
+
+    //==============================================================================
+    /** Attempts to re-load a saved cache of thumbnails from a stream.
+        The cache data must have been written by the writeToStream() method.
+        This will replace all currently-loaded thumbnails with the new data.
+    */
+    bool readFromStream (InputStream& source);
+
+    /** Writes all currently-loaded cache data to a stream.
+        The resulting data can be re-loaded with readFromStream().
+    */
+    void writeToStream (OutputStream& stream);
+
+    /** Returns the thread that client thumbnails can use. */
+    TimeSliceThread& getTimeSliceThread() noexcept      { return thread; }
+
+protected:
+    /** This can be overridden to provide a custom callback for saving thumbnails
+        once they have finished being loaded.
+    */
+    virtual void saveNewlyFinishedThumbnail (const AudioThumbnailBase&, int64 hashCode);
+
+    /** This can be overridden to provide a custom callback for loading thumbnails
+        from pre-saved files to save the cache the trouble of having to create them.
+    */
+    virtual bool loadNewThumb (AudioThumbnailBase&, int64 hashCode);
+
+private:
+    //==============================================================================
+    TimeSliceThread thread;
+
+    class ThumbnailCacheEntry;
+    friend struct ContainerDeletePolicy<ThumbnailCacheEntry>;
+    OwnedArray<ThumbnailCacheEntry> thumbs;
+    CriticalSection lock;
+    int maxNumThumbsToStore;
+
+    ThumbnailCacheEntry* findThumbFor (int64 hash) const;
+    int findOldestThumb() const;
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AudioThumbnailCache)
+};
+
+
+#endif   // JUCE_AUDIOTHUMBNAILCACHE_H_INCLUDED