Add GalleryProvider

app/src/main/java/com/hippo/ehviewer/gallery/DirGalleryProvider.java

@@ -0,0 +1,145 @@
+/*
+ * Copyright 2016 Hippo Seven
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hippo.ehviewer.gallery;
+
+import android.os.Process;
+import android.util.Log;
+
+import com.hippo.image.Image;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FilenameFilter;
+import java.io.InputStream;
+import java.util.Stack;
+
+public class DirGalleryProvider extends GalleryProvider {
+
+    private static final String TAG = DirGalleryProvider.class.getSimpleName();
+
+    private File mDir;
+    private String[] mFiles;
+
+    private final Stack<Integer> mRequests = new Stack<>();
+
+    private boolean mRun = true;
+
+    public DirGalleryProvider(File dir) {
+        mDir = dir;
+        mFiles = mDir.list(new ImageFilter());
+    }
+
+    @Override
+    public void start() {
+        mRun = true;
+        new Decoder().start();
+    }
+
+    @Override
+    public void stop() {
+        mRun = false;
+        synchronized (mRequests) {
+            mRequests.notify();
+        }
+    }
+
+    @Override
+    public int size() {
+        return mFiles != null ? mFiles.length : 0;
+    }
+
+    @Override
+    @Result
+    public int request(int index) {
+        if (index < 0 || index >= size()) {
+            return RESULT_ERROR;
+        } else {
+            synchronized (mRequests) {
+                mRequests.add(index);
+                mRequests.notify();
+            }
+            return RESULT_WAIT;
+        }
+    }
+
+    private static final String[] ENDS = {
+            ".jpg", // Joint Photographic Experts Group
+            ".jpeg",
+            ".png", // Portable Network Graphics
+            ".gif", // Graphics Interchange Format
+    };
+
+    private static class ImageFilter implements FilenameFilter {
+
+        private static boolean endsWith(String str, String[] ends) {
+            if (str == null) {
+                return false;
+            }
+
+            for (int i = 0, n = ends.length; i < n; i++) {
+                if (str.endsWith(ends[i])) {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        @Override
+        public boolean accept(File dir, String filename) {
+            return endsWith(filename.toLowerCase(), ENDS);
+        }
+    }
+
+    private class Decoder extends Thread {
+
+        @Override
+        public void run() {
+            Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
+
+            while (mRun) {
+                int index;
+                synchronized (mRequests) {
+                    if (mRequests.isEmpty()) {
+                        try {
+                            mRequests.wait();
+                        } catch (InterruptedException e) {
+                            // Ignore
+                        }
+                        continue;
+                    }
+                    index = mRequests.pop();
+                }
+
+                try {
+                    InputStream is = new FileInputStream(new File(mDir, mFiles[index]));
+                    Image image = Image.decode(is, false);
+                    if (image != null) {
+                        notifyPageSucceed(index, image);
+                    } else {
+                        notifyPageFailed(index, new Exception("Decode error"));
+                    }
+                } catch (FileNotFoundException e) {
+                    notifyPageFailed(index, e);
+                }
+            }
+
+            Log.i(TAG, "ImageDecoder end");
+        }
+    }
+}