Added ImageDiskCache

1 files changed, 346 insertions, 0 deletions

diff --git a/src/de/danoeh/antennapod/asynctask/ImageDiskCache.java b/src/de/danoeh/antennapod/asynctask/ImageDiskCache.java
new file mode 100644
index 000000000..938f5d968
--- /dev/null
+++ b/src/de/danoeh/antennapod/asynctask/ImageDiskCache.java
@@ -0,0 +1,346 @@
+package de.danoeh.antennapod.asynctask;
+
+import android.util.Log;
+import android.util.Pair;
+import android.widget.ImageView;
+import de.danoeh.antennapod.AppConfig;
+import de.danoeh.antennapod.PodcastApp;
+import org.apache.commons.io.IOUtils;
+
+import java.io.*;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Provides local cache for storing downloaded image. An image disk cache downloads images and stores them as long
+ * as the cache is not full. Once the cache is full, the image disk cache will delete older images.
+ */
+public class ImageDiskCache {
+    private static final String TAG = "ImageDiskCache";
+
+    private static HashMap<String, ImageDiskCache> cacheSingletons = new HashMap<String, ImageDiskCache>();
+
+    /**
+     * Return a default instance of an ImageDiskCache. This cache will store data in the external cache folder.
+     */
+    public static synchronized ImageDiskCache getDefaultInstance() {
+        final String DEFAULT_PATH = "imagecache";
+        final long DEFAULT_MAX_CACHE_SIZE = 10 * 1024 * 1024;
+
+        File cacheDir = PodcastApp.getInstance().getExternalCacheDir();
+        if (cacheDir == null) {
+            return null;
+        }
+        return getInstance(new File(cacheDir, DEFAULT_PATH).getAbsolutePath(), DEFAULT_MAX_CACHE_SIZE);
+    }
+
+    /**
+     * Return an instance of an ImageDiskCache that stores images in the specified folder.
+     */
+    public static synchronized ImageDiskCache getInstance(String path, long maxCacheSize) {
+        if (path == null) {
+            throw new NullPointerException();
+        }
+        ImageDiskCache cache = cacheSingletons.get(path);
+        if (cache == null) {
+            cache = new ImageDiskCache(path, maxCacheSize);
+            cacheSingletons.put(new File(path).getAbsolutePath(), cache);
+        }
+        return cache;
+    }
+
+    /**
+     * Filename - cache object mapping
+     */
+    private static final int KEY_IMAGE_DISK_CACHE = 2;
+    private static final String CACHE_FILE_NAME = "cachefile";
+    private ExecutorService executor;
+    private ConcurrentHashMap<String, DiskCacheObject> diskCache;
+    private final long maxCacheSize;
+    private int cacheSize;
+    private final File cacheFolder;
+
+    private ImageDiskCache(String path, long maxCacheSize) {
+        this.maxCacheSize = maxCacheSize;
+        this.cacheFolder = new File(path);
+        if (!cacheFolder.exists() && !cacheFolder.mkdir()) {
+            throw new IllegalArgumentException("Image disk cache could not create cache folder in: " + path);
+        }
+
+        executor = Executors.newFixedThreadPool(Runtime.getRuntime()
+                .availableProcessors());
+    }
+
+    private synchronized void initCacheFolder() {
+        if (diskCache != null) {
+            File cacheFile = new File(cacheFolder, CACHE_FILE_NAME);
+            if (cacheFile.exists()) {
+                try {
+                    InputStream in = new FileInputStream(cacheFile);
+                    BufferedInputStream buffer = new BufferedInputStream(in);
+                    ObjectInputStream objectInput = new ObjectInputStream(buffer);
+                    diskCache = (ConcurrentHashMap<String, DiskCacheObject>) objectInput.readObject();
+                    // calculate cache size
+                    for (DiskCacheObject dco : diskCache.values()) {
+                        cacheSize += dco.size;
+                    }
+                    deleteInvalidFiles();
+                } catch (IOException e) {
+                    e.printStackTrace();
+                    diskCache = new ConcurrentHashMap<String, DiskCacheObject>();
+                } catch (ClassCastException e) {
+                    e.printStackTrace();
+                    diskCache = new ConcurrentHashMap<String, DiskCacheObject>();
+                } catch (ClassNotFoundException e) {
+                    e.printStackTrace();
+                    diskCache = new ConcurrentHashMap<String, DiskCacheObject>();
+                }
+            } else {
+                diskCache = new ConcurrentHashMap<String, DiskCacheObject>();
+            }
+        }
+    }
+
+    private List<File> getCacheFileList() {
+        Collection<DiskCacheObject> values = diskCache.values();
+        List<File> files = new ArrayList<File>();
+        for (DiskCacheObject dco : values) {
+            files.add(dco.getFile());
+        }
+        files.add(new File(cacheFolder, CACHE_FILE_NAME));
+        return files;
+    }
+
+    private Pair<String, DiskCacheObject> getOldestCacheObject() {
+        Collection<String> keys = diskCache.keySet();
+        DiskCacheObject oldest = null;
+        String oldestKey = null;
+
+        for (String key : keys) {
+
+            if (oldestKey == null) {
+                oldestKey = key;
+                oldest = diskCache.get(key);
+            } else {
+                DiskCacheObject dco = diskCache.get(key);
+                if (oldest.timestamp > dco.timestamp) {
+                    oldestKey = key;
+                    oldest = diskCache.get(key);
+                }
+            }
+        }
+        return new Pair<String, DiskCacheObject>(oldestKey, oldest);
+    }
+
+    private synchronized void deleteCacheObject(String key, DiskCacheObject value) {
+        Log.i(TAG, "Deleting cached object: " + key);
+        diskCache.remove(key);
+        boolean result = value.getFile().delete();
+        if (!result) {
+            Log.w(TAG, "Could not delete file " + value.fileUrl);
+        }
+        cacheSize -= value.size;
+    }
+
+    private synchronized void deleteInvalidFiles() {
+        // delete files that are not stored inside the cache
+        File[] files = cacheFolder.listFiles();
+        List<File> cacheFiles = getCacheFileList();
+        for (File file : files) {
+            if (!cacheFiles.contains(file)) {
+                Log.i(TAG, "Deleting unused file: " + file.getAbsolutePath());
+                boolean result = file.delete();
+                if (!result) {
+                    Log.w(TAG, "Could not delete file: " + file.getAbsolutePath());
+                }
+            }
+        }
+    }
+
+    private synchronized void cleanup() {
+        if (cacheSize > maxCacheSize) {
+            while (cacheSize > maxCacheSize) {
+                Pair<String, DiskCacheObject> oldest = getOldestCacheObject();
+                deleteCacheObject(oldest.first, oldest.second);
+            }
+        }
+    }
+
+    /**
+     * Loads a new image from the disk cache. If the image that the url points to has already been downloaded, the image will
+     * be loaded from the disk. Otherwise, the image will be downloaded first.
+     * The image will be stored in the thumbnail cache.
+     */
+    public synchronized void loadThumbnailBitmap(final String url, final ImageView target) {
+        final ImageLoader il = ImageLoader.getInstance();
+        if (diskCache != null) {
+            DiskCacheObject dco = getFromCacheIfAvailable(url);
+            if (dco != null) {
+                il.loadThumbnailBitmap(dco.loadImage(), target);
+                return;
+            }
+        }
+        target.setTag(KEY_IMAGE_DISK_CACHE, url);
+        executor.submit(new ImageDownloader(url) {
+            @Override
+            protected void onImageLoaded(DiskCacheObject diskCacheObject) {
+                if (target.getTag(KEY_IMAGE_DISK_CACHE) == url) {
+                    il.loadThumbnailBitmap(diskCacheObject.loadImage(), target);
+                }
+            }
+        });
+
+    }
+
+    /**
+     * Loads a new image from the disk cache. If the image that the url points to has already been downloaded, the image will
+     * be loaded from the disk. Otherwise, the image will be downloaded first.
+     * The image will be stored in the cover cache.
+     */
+    public synchronized void loadCoverBitmap(final String url, final ImageView target) {
+        final ImageLoader il = ImageLoader.getInstance();
+        if (diskCache != null) {
+            DiskCacheObject dco = getFromCacheIfAvailable(url);
+            if (dco != null) {
+                il.loadThumbnailBitmap(dco.loadImage(), target);
+                return;
+            }
+        }
+        target.setTag(KEY_IMAGE_DISK_CACHE, url);
+        executor.submit(new ImageDownloader(url) {
+            @Override
+            protected void onImageLoaded(DiskCacheObject diskCacheObject) {
+                if (target.getTag(KEY_IMAGE_DISK_CACHE) == url) {
+                    il.loadCoverBitmap(diskCacheObject.loadImage(), target);
+                }
+            }
+        });
+    }
+
+    private synchronized void addToDiskCache(String url, DiskCacheObject obj) {
+        if (diskCache == null) {
+            initCacheFolder();
+        }
+        if (AppConfig.DEBUG) Log.d(TAG, "Adding new image to disk cache: " + url);
+        diskCache.put(url, obj);
+        cacheSize += obj.size;
+        if (cacheSize > maxCacheSize) {
+            cleanup();
+        }
+    }
+
+    private synchronized DiskCacheObject getFromCacheIfAvailable(String key) {
+        if (diskCache == null) {
+            initCacheFolder();
+        }
+        DiskCacheObject dco = diskCache.get(key);
+        if (dco != null) {
+            dco.timestamp = System.currentTimeMillis();
+        }
+        return dco;
+    }
+
+    private abstract class ImageDownloader implements Runnable {
+        private String downloadUrl;
+
+        public ImageDownloader(String downloadUrl) {
+            this.downloadUrl = downloadUrl;
+        }
+
+        protected abstract void onImageLoaded(DiskCacheObject diskCacheObject);
+
+        public void run() {
+            DiskCacheObject tmp = getFromCacheIfAvailable(downloadUrl);
+            if (tmp != null) {
+                onImageLoaded(tmp);
+                return;
+            }
+
+            InputStream input = null;
+            OutputStream output = null;
+            try {
+                URL url = new URL(downloadUrl);
+                input = url.openStream();
+
+                File newFile = new File(cacheFolder, Integer.toString(downloadUrl.hashCode()));
+                output = new FileOutputStream(newFile);
+                long size = IOUtils.copy(input, output);
+
+                final DiskCacheObject dco = new DiskCacheObject(newFile.getAbsolutePath(), size);
+                addToDiskCache(downloadUrl, dco);
+                onImageLoaded(dco);
+            } catch (MalformedURLException e) {
+                e.printStackTrace();
+            } catch (IOException e) {
+                e.printStackTrace();
+            } finally {
+                IOUtils.closeQuietly(input);
+                IOUtils.closeQuietly(output);
+            }
+        }
+    }
+
+    private static class DiskCacheObject {
+        private final String fileUrl;
+
+        /**
+         * Last usage of this image cache object.
+         */
+        private long timestamp;
+        private final long size;
+
+        public DiskCacheObject(String fileUrl, long size) {
+            if (fileUrl == null) {
+                throw new NullPointerException();
+            }
+            this.fileUrl = fileUrl;
+            this.timestamp = System.currentTimeMillis();
+            this.size = size;
+        }
+
+        public File getFile() {
+            return new File(fileUrl);
+        }
+
+        public ImageLoader.ImageWorkerTaskResource loadImage() {
+            return new ImageLoader.ImageWorkerTaskResource() {
+                FileInputStream in = null;
+
+                @Override
+                public InputStream openImageInputStream() {
+                    try {
+                        return new FileInputStream(getFile());
+                    } catch (FileNotFoundException e) {
+                        e.printStackTrace();
+                    }
+                    return null;
+                }
+
+                @Override
+                public InputStream reopenImageInputStream(InputStream input) {
+                    if (in != null) {
+                        try {
+                            in.close();
+                            return openImageInputStream();
+                        } catch (IOException e) {
+                            e.printStackTrace();
+                        }
+                    }
+                    return null;
+                }
+
+                @Override
+                public String getImageLoaderCacheKey() {
+                    return fileUrl;
+                }
+            };
+        }
+    }
+}