Minor refactor on caches

app/src/main/java/eu/kanade/tachiyomi/data/cache/ChapterCache.java

@@ -44,12 +44,15 @@ public class ChapterCache {
     /** Interface to global information about an application environment. */
     private final Context context;
 
-    /** Google Json class used for parsing json files. */
+    /** Google Json class used for parsing JSON files. */
     private final Gson gson;
 
     /** Cache class used for cache management. */
     private DiskLruCache diskCache;
 
+    /** Page list collection used for deserializing from JSON. */
+    private final Type pageListCollection;
+
     /**
      * Constructor of ChapterCache.
      * @param context application environment interface.
@@ -69,28 +72,10 @@ public class ChapterCache {
                     PARAMETER_CACHE_SIZE
             );
         } catch (IOException e) {
-            // Do Nothing. TODO error handling.
+            // Do Nothing.
         }
-    }
-
-    /**
-     * Remove file from cache.
-     * @param file name of chapter file md5.0.
-     * @return false if file is journal or error else returns status of deletion.
-     */
-    public boolean removeFileFromCache(String file) {
-        // Make sure we don't delete the journal file (keeps track of cache).
-        if (file.equals("journal") || file.startsWith("journal."))
-            return false;
 
-        try {
-            // Take dot(.) substring to get filename without the .0 at the end.
-            String key = file.substring(0, file.lastIndexOf("."));
-            // Remove file from cache.
-            return diskCache.remove(key);
-        } catch (IOException e) {
-            return false;
-        }
+        pageListCollection = new TypeToken<List<Page>>() {}.getType();
     }
 
     /**
@@ -118,64 +103,57 @@ public class ChapterCache {
     }
 
     /**
-     * Get page objects from cache.
-     * @param chapterUrl the url of the chapter.
-     * @return list of chapter pages.
+     * Remove file from cache.
+     * @param file name of file "md5.0".
+     * @return status of deletion for the file.
      */
-    public Observable<List<Page>> getPageUrlsFromDiskCache(final String chapterUrl) {
-        return Observable.create(subscriber -> {
-            try {
-                // Get list of pages from chapterUrl.
-                List<Page> pages = getPageUrlsFromDiskCacheImpl(chapterUrl);
-                // Provides the Observer with a new item to observe.
-                subscriber.onNext(pages);
-                // Notify the Observer that finished sending push-based notifications.
-                subscriber.onCompleted();
-            } catch (Throwable e) {
-                subscriber.onError(e);
-            }
-        });
+    public boolean removeFileFromCache(String file) {
+        // Make sure we don't delete the journal file (keeps track of cache).
+        if (file.equals("journal") || file.startsWith("journal."))
+            return false;
+
+        try {
+            // Remove the extension from the file to get the key of the cache
+            String key = file.substring(0, file.lastIndexOf("."));
+            // Remove file from cache.
+            return diskCache.remove(key);
+        } catch (IOException e) {
+            return false;
+        }
     }
 
     /**
-     * Implementation of the getPageUrlsFromDiskCache() function
-     * @param chapterUrl the url of the chapter
-     * @return returns list of chapter pages
-     * @throws IOException does nothing atm
+     * Get page list from cache.
+     * @param chapterUrl the url of the chapter.
+     * @return an observable of the list of pages.
      */
-    private List<Page> getPageUrlsFromDiskCacheImpl(String chapterUrl) throws IOException /*TODO IOException never thrown*/ {
-        // Initialize snapshot (a snapshot of the values for an entry).
-        DiskLruCache.Snapshot snapshot = null;
-
-        // Initialize list of pages.
-        List<Page> pages = null;
-
-        try {
-            // Create md5 key and retrieve snapshot.
-            String key = DiskUtils.hashKeyForDisk(chapterUrl);
-            snapshot = diskCache.get(key);
+    public Observable<List<Page>> getPageListFromCache(final String chapterUrl) {
+        return Observable.fromCallable(() -> {
+            // Initialize snapshot (a snapshot of the values for an entry).
+            DiskLruCache.Snapshot snapshot = null;
 
+            try {
+                // Create md5 key and retrieve snapshot.
+                String key = DiskUtils.hashKeyForDisk(chapterUrl);
+                snapshot = diskCache.get(key);
 
-            // Convert JSON string to list of objects.
-            Type collectionType = new TypeToken<List<Page>>() {}.getType();
-            pages = gson.fromJson(snapshot.getString(0), collectionType);
+                // Convert JSON string to list of objects.
+                return gson.fromJson(snapshot.getString(0), pageListCollection);
 
-        } catch (IOException e) {
-            // Do Nothing. //TODO error handling?
-        } finally {
-            if (snapshot != null) {
-                snapshot.close();
+            } finally {
+                if (snapshot != null) {
+                    snapshot.close();
+                }
             }
-        }
-        return pages;
+        });
     }
 
     /**
-     * Add page urls to disk cache.
+     * Add page list to disk cache.
      * @param chapterUrl the url of the chapter.
-     * @param pages list of chapter pages.
+     * @param pages list of pages.
      */
-    public void putPageUrlsToDiskCache(final String chapterUrl, final List<Page> pages) {
+    public void putPageListToCache(final String chapterUrl, final List<Page> pages) {
         // Convert list of pages to json string.
         String cachedValue = gson.toJson(pages);
 
@@ -201,7 +179,7 @@ public class ChapterCache {
             diskCache.flush();
             editor.commit();
         } catch (Exception e) {
-            // Do Nothing. TODO error handling?
+            // Do Nothing.
         } finally {
             if (editor != null) {
                 editor.abortUnlessCommitted();
@@ -210,7 +188,7 @@ public class ChapterCache {
                 try {
                     outputStream.close();
                 } catch (IOException ignore) {
-                    // Do Nothing. TODO error handling?
+                    // Do Nothing.
                 }
             }
         }
@@ -225,9 +203,8 @@ public class ChapterCache {
         try {
             return diskCache.get(DiskUtils.hashKeyForDisk(imageUrl)) != null;
         } catch (IOException e) {
-            e.printStackTrace();
+            return false;
         }
-        return false;
     }
 
     /**
@@ -242,18 +219,17 @@ public class ChapterCache {
             File file = new File(diskCache.getDirectory(), imageName);
             return file.getCanonicalPath();
         } catch (IOException e) {
-            e.printStackTrace();
+            return null;
         }
-        return null;
     }
 
     /**
-     * Add image to cache
+     * Add image to cache.
      * @param imageUrl url of image.
      * @param response http response from page.
      * @throws IOException image error.
      */
-    public void putImageToDiskCache(final String imageUrl, final Response response) throws IOException {
+    public void putImageToCache(final String imageUrl, final Response response) throws IOException {
         // Initialize editor (edits the values for an entry).
         DiskLruCache.Editor editor = null;
 
@@ -276,6 +252,7 @@ public class ChapterCache {
             diskCache.flush();
             editor.commit();
         } catch (Exception e) {
+            response.body().close();
             throw new IOException("Unable to save image");
         } finally {
             if (editor != null) {
@@ -285,7 +262,6 @@ public class ChapterCache {
                 sink.close();
             }
         }
-
     }
 
 }

app/src/main/java/eu/kanade/tachiyomi/data/cache/CoverCache.java

@@ -1,6 +1,7 @@
 package eu.kanade.tachiyomi.data.cache;
 
 import android.content.Context;
+import android.support.annotation.Nullable;
 import android.text.TextUtils;
 import android.widget.ImageView;
 
@@ -22,9 +23,9 @@ import eu.kanade.tachiyomi.util.DiskUtils;
 
 /**
  * Class used to create cover cache
- * Makes use of Glide(which can avoid repeating requests) for saving the file.
- * It is not necessary to load the images to the cache.
- * Names of files are created with the md5 of the thumbnailURL
+ * It is used to store the covers of the library.
+ * Makes use of Glide (which can avoid repeating requests) to download covers.
+ * Names of files are created with the md5 of the thumbnail URL
  */
 public class CoverCache {
 
@@ -39,7 +40,7 @@ public class CoverCache {
     private final Context context;
 
     /**
-     * Cache class used for cache management.
+     * Cache directory used for cache management.
      */
     private final File cacheDir;
 
@@ -59,16 +60,16 @@ public class CoverCache {
     }
 
     /**
-     * Check if cache dir exist if not create directory.
+     * Create cache directory if it doesn't exist
      *
-     * @return true if cache dir does exist and is created.
+     * @return true if cache dir is created otherwise false.
      */
     private boolean createCacheDir() {
         return !cacheDir.exists() && cacheDir.mkdirs();
     }
 
     /**
-     * Download the cover with Glide (it can avoid repeating requests) and save the file.
+     * Download the cover with Glide and save the file in this cache.
      *
      * @param thumbnailUrl url of thumbnail.
      * @param headers      headers included in Glide request.
@@ -78,17 +79,15 @@ public class CoverCache {
     }
 
     /**
-     * Download the cover with Glide (it can avoid repeating requests) and save the file.
+     * Download the cover with Glide and save the file.
      *
      * @param thumbnailUrl url of thumbnail.
      * @param headers      headers included in Glide request.
      * @param imageView    imageView where picture should be displayed.
      */
-    private void save(String thumbnailUrl, LazyHeaders headers, ImageView imageView) {
-
+    private void save(String thumbnailUrl, LazyHeaders headers, @Nullable ImageView imageView) {
         // Check if url is empty.
         if (TextUtils.isEmpty(thumbnailUrl))
-            // Do not try and create the string. Instead... only try to realize the truth. There is no string.
             return;
 
         // Download the cover with Glide and save the file.
@@ -107,29 +106,27 @@ public class CoverCache {
                                 loadFromCache(imageView, resource);
                             }
                         } catch (IOException e) {
-                            e.printStackTrace();
+                            // Do nothing.
                         }
                     }
                 });
     }
 
-
     /**
-     * Copy the cover from Glide's cache to local cache.
+     * Copy the cover from Glide's cache to this cache.
      *
      * @param thumbnailUrl url of thumbnail.
      * @param source       the cover image.
-     * @throws IOException TODO not returned atm?
+     * @throws IOException exception returned
      */
     private void copyToLocalCache(String thumbnailUrl, File source) throws IOException {
-        // Create cache directory and check if directory exist
+        // Create cache directory if needed.
         createCacheDir();
 
-        // Create destination file.
+        // Get destination file.
         File dest = new File(cacheDir, DiskUtils.hashKeyForDisk(thumbnailUrl));
 
-
-        // Check if file already exists, if true delete it.
+        // Delete the current file if it exists.
         if (dest.exists())
             dest.delete();
 
@@ -196,26 +193,9 @@ public class CoverCache {
         }
     }
 
-    /**
-     * If the image is already in our cache, use it. If not, load it with glide.
-     * TODO not used atm.
-     *
-     * @param imageView    imageView where picture should be displayed.
-     * @param thumbnailUrl url of thumbnail.
-     * @param headers      headers included in Glide request.
-     */
-    public void loadFromCacheOrNetwork(ImageView imageView, String thumbnailUrl, LazyHeaders headers) {
-        // If localCover exist load it  from cache otherwise load it from network.
-        File localCover = getCoverFromCache(thumbnailUrl);
-        if (localCover.exists()) {
-            loadFromCache(imageView, localCover);
-        } else {
-            loadFromNetwork(imageView, thumbnailUrl, headers);
-        }
-    }
-
     /**
      * Helper method to load the cover from the cache directory into the specified image view.
+     * Glide stores the resized image in its cache to improve performance.
      *
      * @param imageView imageView where picture should be displayed.
      * @param file      file to load. Must exist!.
@@ -230,7 +210,8 @@ public class CoverCache {
 
     /**
      * Helper method to load the cover from network into the specified image view.
-     * It does NOT save the image in cache!
+     * The source image is stored in Glide's cache so that it can be easily copied to this cache
+     * if the manga is added to the library.
      *
      * @param imageView    imageView where picture should be displayed.
      * @param thumbnailUrl url of thumbnail.

app/src/main/java/eu/kanade/tachiyomi/data/source/base/Source.java

@@ -93,7 +93,7 @@ public abstract class Source extends BaseSource {
     }
 
     public Observable<List<Page>> getCachedPageListOrPullFromNetwork(final String chapterUrl) {
-        return chapterCache.getPageUrlsFromDiskCache(getChapterCacheKey(chapterUrl))
+        return chapterCache.getPageListFromCache(getChapterCacheKey(chapterUrl))
                 .onErrorResumeNext(throwable -> {
                     return pullPageListFromNetwork(chapterUrl);
                 })
@@ -168,7 +168,7 @@ public abstract class Source extends BaseSource {
         return getImageProgressResponse(page)
                 .flatMap(resp -> {
                     try {
-                        chapterCache.putImageToDiskCache(page.getImageUrl(), resp);
+                        chapterCache.putImageToCache(page.getImageUrl(), resp);
                     } catch (IOException e) {
                         return Observable.error(e);
                     }
@@ -182,7 +182,7 @@ public abstract class Source extends BaseSource {
 
     public void savePageList(String chapterUrl, List<Page> pages) {
         if (pages != null)
-            chapterCache.putPageUrlsToDiskCache(getChapterCacheKey(chapterUrl), pages);
+            chapterCache.putPageListToCache(getChapterCacheKey(chapterUrl), pages);
     }
 
     protected List<Page> convertToPages(List<String> pageUrls) {