1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.camera.data;
18
19import android.content.ContentResolver;
20import android.database.Cursor;
21import android.net.Uri;
22import android.provider.MediaStore;
23
24import com.android.camera.Storage;
25import com.android.camera.debug.Log;
26
27import java.util.ArrayList;
28import java.util.List;
29
30/**
31 * A set of queries for loading data from a content resolver.
32 */
33public class FilmstripContentQueries {
34    private static final Log.Tag TAG = new Log.Tag("LocalDataQuery");
35    private static final String CAMERA_PATH = Storage.DIRECTORY + "%";
36    private static final String SELECT_BY_PATH = MediaStore.MediaColumns.DATA + " LIKE ?";
37
38    public interface CursorToFilmstripItemFactory<I extends FilmstripItem> {
39
40        /**
41         * Convert a cursor at a given location to a Local Data object.
42         *
43         * @param cursor the current cursor state.
44         * @return a LocalData object that represents the current cursor state.
45         */
46        public I get(Cursor cursor);
47    }
48
49    /**
50     * Query the camera storage directory and convert it to local data
51     * objects.
52     *
53     * @param contentResolver to resolve content with.
54     * @param contentUri to resolve an item at
55     * @param projection the columns to extract
56     * @param minimumId the lower bound of results
57     * @param orderBy the order by clause
58     * @param factory an object that can turn a given cursor into a LocalData object.
59     * @return A list of LocalData objects that satisfy the query.
60     */
61    public static <I extends FilmstripItem> List<I> forCameraPath(ContentResolver contentResolver,
62          Uri contentUri, String[] projection, long minimumId, String orderBy,
63          CursorToFilmstripItemFactory<I> factory) {
64        String selection = SELECT_BY_PATH + " AND " + MediaStore.MediaColumns._ID + " > ?";
65        String[] selectionArgs = new String[] { CAMERA_PATH, Long.toString(minimumId) };
66
67        Cursor cursor = contentResolver.query(contentUri, projection,
68              selection, selectionArgs, orderBy);
69        List<I> result = new ArrayList<>();
70        if (cursor != null) {
71            while (cursor.moveToNext()) {
72                I item = factory.get(cursor);
73                if (item != null) {
74                    result.add(item);
75                } else {
76                    final int dataIndex = cursor.getColumnIndexOrThrow(MediaStore.MediaColumns.DATA);
77                    Log.e(TAG, "Error loading data:" + cursor.getString(dataIndex));
78                }
79            }
80
81            cursor.close();
82        }
83        return result;
84    }
85}