1 files changed, 202 insertions, 0 deletions
diff --git a/src/com/android/gallery3d/widget/LocalPhotoSource.java b/src/com/android/gallery3d/widget/LocalPhotoSource.java
new file mode 100644
index 000000000..de16a7129
--- /dev/null
+++ b/src/com/android/gallery3d/widget/LocalPhotoSource.java
@@ -0,0 +1,202 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * 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.android.gallery3d.widget;
+
+import com.android.gallery3d.app.GalleryApp;
+import com.android.gallery3d.common.Utils;
+import com.android.gallery3d.data.ContentListener;
+import com.android.gallery3d.data.DataManager;
+import com.android.gallery3d.data.MediaItem;
+import com.android.gallery3d.data.Path;
+import com.android.gallery3d.util.GalleryUtils;
+
+import android.content.ContentResolver;
+import android.content.Context;
+import android.database.ContentObserver;
+import android.database.Cursor;
+import android.graphics.Bitmap;
+import android.net.Uri;
+import android.os.Environment;
+import android.os.Handler;
+import android.provider.MediaStore.Images.Media;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Random;
+
+public class LocalPhotoSource implements WidgetSource {
+
+    private static final String TAG = "LocalPhotoSource";
+
+    private static final int MAX_PHOTO_COUNT = 128;
+
+    /* Static fields used to query for the correct set of images */
+    private static final Uri CONTENT_URI = Media.EXTERNAL_CONTENT_URI;
+    private static final String DATE_TAKEN = Media.DATE_TAKEN;
+    private static final String[] PROJECTION = {Media._ID};
+    private static final String[] COUNT_PROJECTION = {"count(*)"};
+    /* We don't want to include the download directory */
+    private static final String SELECTION =
+            String.format("%s != %s", Media.BUCKET_ID, getDownloadBucketId());
+    private static final String ORDER = String.format("%s DESC", DATE_TAKEN);
+
+    private Context mContext;
+    private ArrayList<Long> mPhotos = new ArrayList<Long>();
+    private ContentListener mContentListener;
+    private ContentObserver mContentObserver;
+    private boolean mContentDirty = true;
+    private DataManager mDataManager;
+    private static final Path LOCAL_IMAGE_ROOT = Path.fromString("/local/image/item");
+
+    public LocalPhotoSource(Context context) {
+        mContext = context;
+        mDataManager = ((GalleryApp) context.getApplicationContext()).getDataManager();
+        mContentObserver = new ContentObserver(new Handler()) {
+            @Override
+            public void onChange(boolean selfChange) {
+                mContentDirty = true;
+                if (mContentListener != null) mContentListener.onContentDirty();
+            }
+        };
+        mContext.getContentResolver()
+                .registerContentObserver(CONTENT_URI, true, mContentObserver);
+    }
+
+    public void close() {
+        mContext.getContentResolver().unregisterContentObserver(mContentObserver);
+    }
+
+    @Override
+    public Uri getContentUri(int index) {
+        if (index < mPhotos.size()) {
+            return CONTENT_URI.buildUpon()
+                    .appendPath(String.valueOf(mPhotos.get(index)))
+                    .build();
+        }
+        return null;
+    }
+
+    @Override
+    public Bitmap getImage(int index) {
+        if (index >= mPhotos.size()) return null;
+        long id = mPhotos.get(index);
+        MediaItem image = (MediaItem)
+                mDataManager.getMediaObject(LOCAL_IMAGE_ROOT.getChild(id));
+        if (image == null) return null;
+
+        return WidgetUtils.createWidgetBitmap(image);
+    }
+
+    private int[] getExponentialIndice(int total, int count) {
+        Random random = new Random();
+        if (count > total) count = total;
+        HashSet<Integer> selected = new HashSet<Integer>(count);
+        while (selected.size() < count) {
+            int row = (int)(-Math.log(random.nextDouble()) * total / 2);
+            if (row < total) selected.add(row);
+        }
+        int values[] = new int[count];
+        int index = 0;
+        for (int value : selected) {
+            values[index++] = value;
+        }
+        return values;
+    }
+
+    private int getPhotoCount(ContentResolver resolver) {
+        Cursor cursor = resolver.query(
+                CONTENT_URI, COUNT_PROJECTION, SELECTION, null, null);
+        if (cursor == null) return 0;
+        try {
+            Utils.assertTrue(cursor.moveToNext());
+            return cursor.getInt(0);
+        } finally {
+            cursor.close();
+        }
+    }
+
+    private boolean isContentSound(int totalCount) {
+        if (mPhotos.size() < Math.min(totalCount, MAX_PHOTO_COUNT)) return false;
+        if (mPhotos.size() == 0) return true; // totalCount is also 0
+
+        StringBuilder builder = new StringBuilder();
+        for (Long imageId : mPhotos) {
+            if (builder.length() > 0) builder.append(",");
+            builder.append(imageId);
+        }
+        Cursor cursor = mContext.getContentResolver().query(
+                CONTENT_URI, COUNT_PROJECTION,
+                String.format("%s in (%s)", Media._ID, builder.toString()),
+                null, null);
+        if (cursor == null) return false;
+        try {
+            Utils.assertTrue(cursor.moveToNext());
+            return cursor.getInt(0) == mPhotos.size();
+        } finally {
+            cursor.close();
+        }
+    }
+
+    public void reload() {
+        if (!mContentDirty) return;
+        mContentDirty = false;
+
+        ContentResolver resolver = mContext.getContentResolver();
+        int photoCount = getPhotoCount(resolver);
+        if (isContentSound(photoCount)) return;
+
+        int choosedIds[] = getExponentialIndice(photoCount, MAX_PHOTO_COUNT);
+        Arrays.sort(choosedIds);
+
+        mPhotos.clear();
+        Cursor cursor = mContext.getContentResolver().query(
+                CONTENT_URI, PROJECTION, SELECTION, null, ORDER);
+        if (cursor == null) return;
+        try {
+            for (int index : choosedIds) {
+                if (cursor.moveToPosition(index)) {
+                    mPhotos.add(cursor.getLong(0));
+                }
+            }
+        } finally {
+            cursor.close();
+        }
+    }
+
+    @Override
+    public int size() {
+        reload();
+        return mPhotos.size();
+    }
+
+    /**
+     * Builds the bucket ID for the public external storage Downloads directory
+     * @return the bucket ID
+     */
+    private static int getDownloadBucketId() {
+        String downloadsPath = Environment
+                .getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS)
+                .getAbsolutePath();
+        return GalleryUtils.getBucketId(downloadsPath);
+    }
+
+    @Override
+    public void setContentListener(ContentListener listener) {
+        mContentListener = listener;
+    }
+}