src/com/android/photos/data/PhotoProvider.java - LeafOS-Project/android_packages_apps_Gallery2 - Gitiles

 /*
  * Copyright (C) 2013 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.photos.data;

 import android.content.ContentResolver;
 import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.Context;
 import android.content.UriMatcher;
 import android.database.Cursor;
 import android.database.DatabaseUtils;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.database.sqlite.SQLiteQueryBuilder;
 import android.media.ExifInterface;
 import android.net.Uri;
 import android.os.CancellationSignal;
 import android.provider.BaseColumns;

 import java.util.List;

 /**
  * A provider that gives access to photo and video information for media stored
  * on the server. Only media that is or will be put on the server will be
  * accessed by this provider. Use Photos.CONTENT_URI to query all photos and
  * videos. Use Albums.CONTENT_URI to query all albums. Use Metadata.CONTENT_URI
  * to query metadata about a photo or video, based on the ID of the media. Use
  * ImageCache.THUMBNAIL_CONTENT_URI, ImageCache.PREVIEW_CONTENT_URI, or
  * ImageCache.ORIGINAL_CONTENT_URI to query the path of the thumbnail, preview,
  * or original-sized image respectfully. <br/>
  * To add or update metadata, use the update function rather than insert. All
  * values for the metadata must be in the ContentValues, even if they are also
  * in the selection. The selection and selectionArgs are not used when updating
  * metadata. If the metadata values are null, the row will be deleted.
  */
 public class PhotoProvider extends SQLiteContentProvider {
     @SuppressWarnings("unused")
     private static final String TAG = PhotoProvider.class.getSimpleName();

     protected static final String DB_NAME = "photo.db";
     public static final String AUTHORITY = PhotoProviderAuthority.AUTHORITY;
     static final Uri BASE_CONTENT_URI = new Uri.Builder().scheme("content").authority(AUTHORITY)
             .build();

     // Used to allow mocking out the change notification because
     // MockContextResolver disallows system-wide notification.
     public static interface ChangeNotification {
         void notifyChange(Uri uri, boolean syncToNetwork);
     }

     /**
      * Contains columns that can be accessed via Accounts.CONTENT_URI
      */
     public static interface Accounts extends BaseColumns {
         /**
          * Internal database table used for account information
          */
         public static final String TABLE = "accounts";
         /**
          * Content URI for account information
          */
         public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);
         /**
          * User name for this account.
          */
         public static final String ACCOUNT_NAME = "name";
     }

     /**
      * Contains columns that can be accessed via Photos.CONTENT_URI.
      */
     public static interface Photos extends BaseColumns {
         /** Internal database table used for basic photo information. */
         public static final String TABLE = "photo";
         /** Content URI for basic photo and video information. */
         public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);

         /** Long foreign key to Accounts._ID */
         public static final String ACCOUNT_ID = "account_id";
         /** Column name for the width of the original image. Integer value. */
         public static final String WIDTH = "width";
         /** Column name for the height of the original image. Integer value. */
         public static final String HEIGHT = "height";
         /**
          * Column name for the date that the original image was taken. Long
          * value indicating the milliseconds since epoch in the GMT time zone.
          */
         public static final String DATE_TAKEN = "date_taken";
         /**
          * Column name indicating the long value of the album id that this image
          * resides in. Will be NULL if it it has not been uploaded to the
          * server.
          */
         public static final String ALBUM_ID = "album_id";
         /** The column name for the mime-type String. */
         public static final String MIME_TYPE = "mime_type";
         /** The title of the photo. String value. */
         public static final String TITLE = "title";
         /** The date the photo entry was last updated. Long value. */
         public static final String DATE_MODIFIED = "date_modified";
         /**
          * The rotation of the photo in degrees, if rotation has not already
          * been applied. Integer value.
          */
         public static final String ROTATION = "rotation";
     }

     /**
      * Contains columns and Uri for accessing album information.
      */
     public static interface Albums extends BaseColumns {
         /** Internal database table used album information. */
         public static final String TABLE = "album";
         /** Content URI for album information. */
         public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);

         /** Long foreign key to Accounts._ID */
         public static final String ACCOUNT_ID = "account_id";
         /** Parent directory or null if this is in the root. */
         public static final String PARENT_ID = "parent_id";
         /**
          * Column name for the visibility level of the album. Can be any of the
          * VISIBILITY_* values.
          */
         public static final String VISIBILITY = "visibility";
         /** The user-specified location associated with the album. String value. */
         public static final String LOCATION_STRING = "location_string";
         /** The title of the album. String value. */
         public static final String TITLE = "title";
         /** A short summary of the contents of the album. String value. */
         public static final String SUMMARY = "summary";
         /** The date the album was created. Long value */
         public static final String DATE_PUBLISHED = "date_published";
         /** The date the album entry was last updated. Long value. */
         public static final String DATE_MODIFIED = "date_modified";

         // Privacy values for Albums.VISIBILITY
         public static final int VISIBILITY_PRIVATE = 1;
         public static final int VISIBILITY_SHARED = 2;
         public static final int VISIBILITY_PUBLIC = 3;
     }

     /**
      * Contains columns and Uri for accessing photo and video metadata
      */
     public static interface Metadata extends BaseColumns {
         /** Internal database table used metadata information. */
         public static final String TABLE = "metadata";
         /** Content URI for photo and video metadata. */
         public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);
         /** Foreign key to photo_id. Long value. */
         public static final String PHOTO_ID = "photo_id";
         /** Metadata key. String value */
         public static final String KEY = "key";
         /**
          * Metadata value. Type is based on key.
          */
         public static final String VALUE = "value";

         /** A short summary of the photo. String value. */
         public static final String KEY_SUMMARY = "summary";
         /** The date the photo was added. Long value. */
         public static final String KEY_PUBLISHED = "date_published";
         /** The date the photo was last updated. Long value. */
         public static final String KEY_DATE_UPDATED = "date_updated";
         /** The size of the photo is bytes. Integer value. */
         public static final String KEY_SIZE_IN_BTYES = "size";
         /** The latitude associated with the photo. Double value. */
         public static final String KEY_LATITUDE = "latitude";
         /** The longitude associated with the photo. Double value. */
         public static final String KEY_LONGITUDE = "longitude";

         /** The make of the camera used. String value. */
         public static final String KEY_EXIF_MAKE = ExifInterface.TAG_MAKE;
         /** The model of the camera used. String value. */
         public static final String KEY_EXIF_MODEL = ExifInterface.TAG_MODEL;;
         /** The exposure time used. Float value. */
         public static final String KEY_EXIF_EXPOSURE = ExifInterface.TAG_EXPOSURE_TIME;
         /** Whether the flash was used. Boolean value. */
         public static final String KEY_EXIF_FLASH = ExifInterface.TAG_FLASH;
         /** The focal length used. Float value. */
         public static final String KEY_EXIF_FOCAL_LENGTH = ExifInterface.TAG_FOCAL_LENGTH;
         /** The fstop value used. Float value. */
         public static final String KEY_EXIF_FSTOP = ExifInterface.TAG_APERTURE;
         /** The ISO equivalent value used. Integer value. */
         public static final String KEY_EXIF_ISO = ExifInterface.TAG_ISO;
     }

     /**
      * Contains columns and Uri for maintaining the image cache.
      */
     public static interface ImageCache extends BaseColumns {
         /** Internal database table used for the image cache */
         public static final String TABLE = "image_cache";

         /**
          * The image_type query parameter required for accessing a specific
          * image
          */
         public static final String IMAGE_TYPE_QUERY_PARAMETER = "image_type";

         // ImageCache.IMAGE_TYPE values
         public static final int IMAGE_TYPE_ALBUM_COVER = 1;
         public static final int IMAGE_TYPE_THUMBNAIL = 2;
         public static final int IMAGE_TYPE_PREVIEW = 3;
         public static final int IMAGE_TYPE_ORIGINAL = 4;

         /**
          * Content URI for retrieving image paths. The
          * IMAGE_TYPE_QUERY_PARAMETER must be used in queries.
          */
         public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);

         /**
          * Content URI for retrieving the album cover art. The album ID must be
          * appended to the URI.
          */
         public static final Uri ALBUM_COVER_CONTENT_URI = Uri.withAppendedPath(CONTENT_URI,
                 Albums.TABLE);

         /**
          * An _ID from Albums or Photos, depending on whether IMAGE_TYPE is
          * IMAGE_TYPE_ALBUM or not. Long value.
          */
         public static final String REMOTE_ID = "remote_id";
         /** One of IMAGE_TYPE_* values. */
         public static final String IMAGE_TYPE = "image_type";
         /** The String path to the image. */
         public static final String PATH = "path";
     };

     // SQL used within this class.
     protected static final String WHERE_ID = BaseColumns._ID + " = ?";
     protected static final String WHERE_METADATA_ID = Metadata.PHOTO_ID + " = ? AND "
             + Metadata.KEY + " = ?";

     protected static final String SELECT_ALBUM_ID = "SELECT " + Albums._ID + " FROM "
             + Albums.TABLE;
     protected static final String SELECT_PHOTO_ID = "SELECT " + Photos._ID + " FROM "
             + Photos.TABLE;
     protected static final String SELECT_PHOTO_COUNT = "SELECT COUNT(*) FROM " + Photos.TABLE;
     protected static final String DELETE_PHOTOS = "DELETE FROM " + Photos.TABLE;
     protected static final String DELETE_METADATA = "DELETE FROM " + Metadata.TABLE;
     protected static final String SELECT_METADATA_COUNT = "SELECT COUNT(*) FROM " + Metadata.TABLE;
     protected static final String WHERE = " WHERE ";
     protected static final String IN = " IN ";
     protected static final String NESTED_SELECT_START = "(";
     protected static final String NESTED_SELECT_END = ")";

     /**
      * For selecting the mime-type for an image.
      */
     private static final String[] PROJECTION_MIME_TYPE = {
         Photos.MIME_TYPE,
     };

     private static final String[] BASE_COLUMNS_ID = {
         BaseColumns._ID,
     };

     protected ChangeNotification mNotifier = null;
     protected static final UriMatcher sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

     protected static final int MATCH_PHOTO = 1;
     protected static final int MATCH_PHOTO_ID = 2;
     protected static final int MATCH_ALBUM = 3;
     protected static final int MATCH_ALBUM_ID = 4;
     protected static final int MATCH_METADATA = 5;
     protected static final int MATCH_METADATA_ID = 6;
     protected static final int MATCH_IMAGE = 7;
     protected static final int MATCH_ALBUM_COVER = 8;

     static {
         sUriMatcher.addURI(AUTHORITY, Photos.TABLE, MATCH_PHOTO);
         // match against Photos._ID
         sUriMatcher.addURI(AUTHORITY, Photos.TABLE + "/#", MATCH_PHOTO_ID);
         sUriMatcher.addURI(AUTHORITY, Albums.TABLE, MATCH_ALBUM);
         // match against Albums._ID
         sUriMatcher.addURI(AUTHORITY, Albums.TABLE + "/#", MATCH_ALBUM_ID);
         sUriMatcher.addURI(AUTHORITY, Metadata.TABLE, MATCH_METADATA);
         // match against metadata/<Metadata._ID>
         sUriMatcher.addURI(AUTHORITY, Metadata.TABLE + "/#", MATCH_METADATA_ID);
         // match against image_cache/<ImageCache.PHOTO_ID>
         sUriMatcher.addURI(AUTHORITY, ImageCache.TABLE + "/#", MATCH_IMAGE);
         // match against image_cache/album/<Albums._ID>
         sUriMatcher.addURI(AUTHORITY, ImageCache.TABLE + "/" + Albums.TABLE + "/#",
                 MATCH_ALBUM_COVER);
     }

     @Override
     public int deleteInTransaction(Uri uri, String selection, String[] selectionArgs,
             boolean callerIsSyncAdapter) {
         int match = matchUri(uri);
         selection = addIdToSelection(match, selection);
         selectionArgs = addIdToSelectionArgs(match, uri, selectionArgs);
         int deleted = 0;
         SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();
         deleted = deleteCascade(db, match, selection, selectionArgs, uri);
         return deleted;
     }

     @Override
     public String getType(Uri uri) {
         Cursor cursor = query(uri, PROJECTION_MIME_TYPE, null, null, null);
         String mimeType = null;
         if (cursor.moveToNext()) {
             mimeType = cursor.getString(0);
         }
         cursor.close();
         return mimeType;
     }

     @Override
     public Uri insertInTransaction(Uri uri, ContentValues values, boolean callerIsSyncAdapter) {
         int match = matchUri(uri);
         validateMatchTable(match);
         String table = getTableFromMatch(match, uri);
         SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();
         Uri insertedUri = null;
         long id = db.insert(table, null, values);
         if (id != -1) {
             // uri already matches the table.
             insertedUri = ContentUris.withAppendedId(uri, id);
             postNotifyUri(insertedUri);
         }
         return insertedUri;
     }

     @Override
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder) {
         return query(uri, projection, selection, selectionArgs, sortOrder, null);
     }

     @Override
     public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
             String sortOrder, CancellationSignal cancellationSignal) {
         int match = matchUri(uri);
         selection = addIdToSelection(match, selection);
         selectionArgs = addIdToSelectionArgs(match, uri, selectionArgs);
         String table = getTableFromMatch(match, uri);
         SQLiteDatabase db = getDatabaseHelper().getReadableDatabase();
         return db.query(false, table, projection, selection, selectionArgs, null, null, sortOrder,
                 null, cancellationSignal);
     }

     @Override
     public int updateInTransaction(Uri uri, ContentValues values, String selection,
             String[] selectionArgs, boolean callerIsSyncAdapter) {
         int match = matchUri(uri);
         int rowsUpdated = 0;
         SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();
         if (match == MATCH_METADATA) {
             rowsUpdated = modifyMetadata(db, values);
         } else {
             selection = addIdToSelection(match, selection);
             selectionArgs = addIdToSelectionArgs(match, uri, selectionArgs);
             String table = getTableFromMatch(match, uri);
             rowsUpdated = db.update(table, values, selection, selectionArgs);
         }
         postNotifyUri(uri);
         return rowsUpdated;
     }

     public void setMockNotification(ChangeNotification notification) {
         mNotifier = notification;
     }

     protected static String addIdToSelection(int match, String selection) {
         String where;
         switch (match) {
             case MATCH_PHOTO_ID:
             case MATCH_ALBUM_ID:
             case MATCH_METADATA_ID:
                 where = WHERE_ID;
                 break;
             default:
                 return selection;
         }
         return DatabaseUtils.concatenateWhere(selection, where);
     }

     protected static String[] addIdToSelectionArgs(int match, Uri uri, String[] selectionArgs) {
         String[] whereArgs;
         switch (match) {
             case MATCH_PHOTO_ID:
             case MATCH_ALBUM_ID:
             case MATCH_METADATA_ID:
                 whereArgs = new String[] {
                     uri.getPathSegments().get(1),
                 };
                 break;
             default:
                 return selectionArgs;
         }
         return DatabaseUtils.appendSelectionArgs(selectionArgs, whereArgs);
     }

     protected static String[] addMetadataKeysToSelectionArgs(String[] selectionArgs, Uri uri) {
         List<String> segments = uri.getPathSegments();
         String[] additionalArgs = {
                 segments.get(1),
                 segments.get(2),
         };

         return DatabaseUtils.appendSelectionArgs(selectionArgs, additionalArgs);
     }

     protected static String getTableFromMatch(int match, Uri uri) {
         String table;
         switch (match) {
             case MATCH_PHOTO:
             case MATCH_PHOTO_ID:
                 table = Photos.TABLE;
                 break;
             case MATCH_ALBUM:
             case MATCH_ALBUM_ID:
                 table = Albums.TABLE;
                 break;
             case MATCH_METADATA:
             case MATCH_METADATA_ID:
                 table = Metadata.TABLE;
                 break;
             default:
                 throw unknownUri(uri);
         }
         return table;
     }

     @Override
     public SQLiteOpenHelper getDatabaseHelper(Context context) {
         return new PhotoDatabase(context, DB_NAME);
     }

     private int modifyMetadata(SQLiteDatabase db, ContentValues values) {
         int rowCount;
         if (values.get(Metadata.VALUE) == null) {
             String[] selectionArgs = {
                     values.getAsString(Metadata.PHOTO_ID), values.getAsString(Metadata.KEY),
             };
             rowCount = db.delete(Metadata.TABLE, WHERE_METADATA_ID, selectionArgs);
         } else {
             long rowId = db.replace(Metadata.TABLE, null, values);
             rowCount = (rowId == -1) ? 0 : 1;
         }
         return rowCount;
     }

     private int matchUri(Uri uri) {
         int match = sUriMatcher.match(uri);
         if (match == UriMatcher.NO_MATCH) {
             throw unknownUri(uri);
         }
         if (match == MATCH_IMAGE || match == MATCH_ALBUM_COVER) {
             throw new IllegalArgumentException("Operation not allowed on image cache database");
         }
         return match;
     }

     @Override
     protected void notifyChange(ContentResolver resolver, Uri uri, boolean syncToNetwork) {
         if (mNotifier != null) {
             mNotifier.notifyChange(uri, syncToNetwork);
         } else {
             resolver.notifyChange(uri, null, syncToNetwork);
         }
     }

     protected static IllegalArgumentException unknownUri(Uri uri) {
         return new IllegalArgumentException("Unknown Uri format: " + uri);
     }

     protected static String nestWhere(String matchColumn, String table, String nestedWhere) {
         String query = SQLiteQueryBuilder.buildQueryString(false, table, BASE_COLUMNS_ID,
                 nestedWhere, null, null, null, null);
         return matchColumn + IN + NESTED_SELECT_START + query + NESTED_SELECT_END;
     }

     protected int deleteCascade(SQLiteDatabase db, int match, String selection,
             String[] selectionArgs, Uri uri) {
         switch (match) {
             case MATCH_PHOTO:
             case MATCH_PHOTO_ID: {
                 deleteCascadeMetadata(db, selection, selectionArgs);
                 break;
             }
             case MATCH_ALBUM:
             case MATCH_ALBUM_ID: {
                 deleteCascadePhotos(db, selection, selectionArgs);
                 break;
             }
         }
         String table = getTableFromMatch(match, uri);
         int deleted = db.delete(table, selection, selectionArgs);
         if (deleted > 0) {
             postNotifyUri(uri);
         }
         return deleted;
     }

     private void deleteCascadePhotos(SQLiteDatabase db, String albumSelect,
             String[] selectArgs) {
         String photoWhere = nestWhere(Photos.ALBUM_ID, Albums.TABLE, albumSelect);
         deleteCascadeMetadata(db, photoWhere, selectArgs);
         int deleted = db.delete(Photos.TABLE, photoWhere, selectArgs);
         if (deleted > 0) {
             postNotifyUri(Photos.CONTENT_URI);
         }
     }

     private void deleteCascadeMetadata(SQLiteDatabase db, String photosSelect,
             String[] selectArgs) {
         String metadataWhere = nestWhere(Metadata.PHOTO_ID, Photos.TABLE, photosSelect);
         int deleted = db.delete(Metadata.TABLE, metadataWhere, selectArgs);
         if (deleted > 0) {
             postNotifyUri(Metadata.CONTENT_URI);
         }
     }

     private static void validateMatchTable(int match) {
         switch (match) {
             case MATCH_PHOTO:
             case MATCH_ALBUM:
             case MATCH_METADATA:
                 break;
             default:
                 throw new IllegalArgumentException("Operation not allowed on an existing row.");
         }
     }
 }
	/*
	* Copyright (C) 2013 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.photos.data;

	import android.content.ContentResolver;
	import android.content.ContentUris;
	import android.content.ContentValues;
	import android.content.Context;
	import android.content.UriMatcher;
	import android.database.Cursor;
	import android.database.DatabaseUtils;
	import android.database.sqlite.SQLiteDatabase;
	import android.database.sqlite.SQLiteOpenHelper;
	import android.database.sqlite.SQLiteQueryBuilder;
	import android.media.ExifInterface;
	import android.net.Uri;
	import android.os.CancellationSignal;
	import android.provider.BaseColumns;

	import java.util.List;

	/**
	* A provider that gives access to photo and video information for media stored
	* on the server. Only media that is or will be put on the server will be
	* accessed by this provider. Use Photos.CONTENT_URI to query all photos and
	* videos. Use Albums.CONTENT_URI to query all albums. Use Metadata.CONTENT_URI
	* to query metadata about a photo or video, based on the ID of the media. Use
	* ImageCache.THUMBNAIL_CONTENT_URI, ImageCache.PREVIEW_CONTENT_URI, or
	* ImageCache.ORIGINAL_CONTENT_URI to query the path of the thumbnail, preview,
	* or original-sized image respectfully. <br/>
	* To add or update metadata, use the update function rather than insert. All
	* values for the metadata must be in the ContentValues, even if they are also
	* in the selection. The selection and selectionArgs are not used when updating
	* metadata. If the metadata values are null, the row will be deleted.
	*/
	public class PhotoProvider extends SQLiteContentProvider {
	@SuppressWarnings("unused")
	private static final String TAG = PhotoProvider.class.getSimpleName();

	protected static final String DB_NAME = "photo.db";
	public static final String AUTHORITY = PhotoProviderAuthority.AUTHORITY;
	static final Uri BASE_CONTENT_URI = new Uri.Builder().scheme("content").authority(AUTHORITY)
	.build();

	// Used to allow mocking out the change notification because
	// MockContextResolver disallows system-wide notification.
	public static interface ChangeNotification {
	void notifyChange(Uri uri, boolean syncToNetwork);
	}

	/**
	* Contains columns that can be accessed via Accounts.CONTENT_URI
	*/
	public static interface Accounts extends BaseColumns {
	/**
	* Internal database table used for account information
	*/
	public static final String TABLE = "accounts";
	/**
	* Content URI for account information
	*/
	public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);
	/**
	* User name for this account.
	*/
	public static final String ACCOUNT_NAME = "name";
	}

	/**
	* Contains columns that can be accessed via Photos.CONTENT_URI.
	*/
	public static interface Photos extends BaseColumns {
	/** Internal database table used for basic photo information. */
	public static final String TABLE = "photo";
	/** Content URI for basic photo and video information. */
	public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);

	/** Long foreign key to Accounts._ID */
	public static final String ACCOUNT_ID = "account_id";
	/** Column name for the width of the original image. Integer value. */
	public static final String WIDTH = "width";
	/** Column name for the height of the original image. Integer value. */
	public static final String HEIGHT = "height";
	/**
	* Column name for the date that the original image was taken. Long
	* value indicating the milliseconds since epoch in the GMT time zone.
	*/
	public static final String DATE_TAKEN = "date_taken";
	/**
	* Column name indicating the long value of the album id that this image
	* resides in. Will be NULL if it it has not been uploaded to the
	* server.
	*/
	public static final String ALBUM_ID = "album_id";
	/** The column name for the mime-type String. */
	public static final String MIME_TYPE = "mime_type";
	/** The title of the photo. String value. */
	public static final String TITLE = "title";
	/** The date the photo entry was last updated. Long value. */
	public static final String DATE_MODIFIED = "date_modified";
	/**
	* The rotation of the photo in degrees, if rotation has not already
	* been applied. Integer value.
	*/
	public static final String ROTATION = "rotation";
	}

	/**
	* Contains columns and Uri for accessing album information.
	*/
	public static interface Albums extends BaseColumns {
	/** Internal database table used album information. */
	public static final String TABLE = "album";
	/** Content URI for album information. */
	public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);

	/** Long foreign key to Accounts._ID */
	public static final String ACCOUNT_ID = "account_id";
	/** Parent directory or null if this is in the root. */
	public static final String PARENT_ID = "parent_id";
	/**
	* Column name for the visibility level of the album. Can be any of the
	* VISIBILITY_* values.
	*/
	public static final String VISIBILITY = "visibility";
	/** The user-specified location associated with the album. String value. */
	public static final String LOCATION_STRING = "location_string";
	/** The title of the album. String value. */
	public static final String TITLE = "title";
	/** A short summary of the contents of the album. String value. */
	public static final String SUMMARY = "summary";
	/** The date the album was created. Long value */
	public static final String DATE_PUBLISHED = "date_published";
	/** The date the album entry was last updated. Long value. */
	public static final String DATE_MODIFIED = "date_modified";

	// Privacy values for Albums.VISIBILITY
	public static final int VISIBILITY_PRIVATE = 1;
	public static final int VISIBILITY_SHARED = 2;
	public static final int VISIBILITY_PUBLIC = 3;
	}

	/**
	* Contains columns and Uri for accessing photo and video metadata
	*/
	public static interface Metadata extends BaseColumns {
	/** Internal database table used metadata information. */
	public static final String TABLE = "metadata";
	/** Content URI for photo and video metadata. */
	public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);
	/** Foreign key to photo_id. Long value. */
	public static final String PHOTO_ID = "photo_id";
	/** Metadata key. String value */
	public static final String KEY = "key";
	/**
	* Metadata value. Type is based on key.
	*/
	public static final String VALUE = "value";

	/** A short summary of the photo. String value. */
	public static final String KEY_SUMMARY = "summary";
	/** The date the photo was added. Long value. */
	public static final String KEY_PUBLISHED = "date_published";
	/** The date the photo was last updated. Long value. */
	public static final String KEY_DATE_UPDATED = "date_updated";
	/** The size of the photo is bytes. Integer value. */
	public static final String KEY_SIZE_IN_BTYES = "size";
	/** The latitude associated with the photo. Double value. */
	public static final String KEY_LATITUDE = "latitude";
	/** The longitude associated with the photo. Double value. */
	public static final String KEY_LONGITUDE = "longitude";

	/** The make of the camera used. String value. */
	public static final String KEY_EXIF_MAKE = ExifInterface.TAG_MAKE;
	/** The model of the camera used. String value. */
	public static final String KEY_EXIF_MODEL = ExifInterface.TAG_MODEL;;
	/** The exposure time used. Float value. */
	public static final String KEY_EXIF_EXPOSURE = ExifInterface.TAG_EXPOSURE_TIME;
	/** Whether the flash was used. Boolean value. */
	public static final String KEY_EXIF_FLASH = ExifInterface.TAG_FLASH;
	/** The focal length used. Float value. */
	public static final String KEY_EXIF_FOCAL_LENGTH = ExifInterface.TAG_FOCAL_LENGTH;
	/** The fstop value used. Float value. */
	public static final String KEY_EXIF_FSTOP = ExifInterface.TAG_APERTURE;
	/** The ISO equivalent value used. Integer value. */
	public static final String KEY_EXIF_ISO = ExifInterface.TAG_ISO;
	}

	/**
	* Contains columns and Uri for maintaining the image cache.
	*/
	public static interface ImageCache extends BaseColumns {
	/** Internal database table used for the image cache */
	public static final String TABLE = "image_cache";

	/**
	* The image_type query parameter required for accessing a specific
	* image
	*/
	public static final String IMAGE_TYPE_QUERY_PARAMETER = "image_type";

	// ImageCache.IMAGE_TYPE values
	public static final int IMAGE_TYPE_ALBUM_COVER = 1;
	public static final int IMAGE_TYPE_THUMBNAIL = 2;
	public static final int IMAGE_TYPE_PREVIEW = 3;
	public static final int IMAGE_TYPE_ORIGINAL = 4;

	/**
	* Content URI for retrieving image paths. The
	* IMAGE_TYPE_QUERY_PARAMETER must be used in queries.
	*/
	public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, TABLE);

	/**
	* Content URI for retrieving the album cover art. The album ID must be
	* appended to the URI.
	*/
	public static final Uri ALBUM_COVER_CONTENT_URI = Uri.withAppendedPath(CONTENT_URI,
	Albums.TABLE);

	/**
	* An _ID from Albums or Photos, depending on whether IMAGE_TYPE is
	* IMAGE_TYPE_ALBUM or not. Long value.
	*/
	public static final String REMOTE_ID = "remote_id";
	/** One of IMAGE_TYPE_* values. */
	public static final String IMAGE_TYPE = "image_type";
	/** The String path to the image. */
	public static final String PATH = "path";
	};

	// SQL used within this class.
	protected static final String WHERE_ID = BaseColumns._ID + " = ?";
	protected static final String WHERE_METADATA_ID = Metadata.PHOTO_ID + " = ? AND "
	+ Metadata.KEY + " = ?";

	protected static final String SELECT_ALBUM_ID = "SELECT " + Albums._ID + " FROM "
	+ Albums.TABLE;
	protected static final String SELECT_PHOTO_ID = "SELECT " + Photos._ID + " FROM "
	+ Photos.TABLE;
	protected static final String SELECT_PHOTO_COUNT = "SELECT COUNT(*) FROM " + Photos.TABLE;
	protected static final String DELETE_PHOTOS = "DELETE FROM " + Photos.TABLE;
	protected static final String DELETE_METADATA = "DELETE FROM " + Metadata.TABLE;
	protected static final String SELECT_METADATA_COUNT = "SELECT COUNT(*) FROM " + Metadata.TABLE;
	protected static final String WHERE = " WHERE ";
	protected static final String IN = " IN ";
	protected static final String NESTED_SELECT_START = "(";
	protected static final String NESTED_SELECT_END = ")";

	/**
	* For selecting the mime-type for an image.
	*/
	private static final String[] PROJECTION_MIME_TYPE = {
	Photos.MIME_TYPE,
	};

	private static final String[] BASE_COLUMNS_ID = {
	BaseColumns._ID,
	};

	protected ChangeNotification mNotifier = null;
	protected static final UriMatcher sUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);

	protected static final int MATCH_PHOTO = 1;
	protected static final int MATCH_PHOTO_ID = 2;
	protected static final int MATCH_ALBUM = 3;
	protected static final int MATCH_ALBUM_ID = 4;
	protected static final int MATCH_METADATA = 5;
	protected static final int MATCH_METADATA_ID = 6;
	protected static final int MATCH_IMAGE = 7;
	protected static final int MATCH_ALBUM_COVER = 8;

	static {
	sUriMatcher.addURI(AUTHORITY, Photos.TABLE, MATCH_PHOTO);
	// match against Photos._ID
	sUriMatcher.addURI(AUTHORITY, Photos.TABLE + "/#", MATCH_PHOTO_ID);
	sUriMatcher.addURI(AUTHORITY, Albums.TABLE, MATCH_ALBUM);
	// match against Albums._ID
	sUriMatcher.addURI(AUTHORITY, Albums.TABLE + "/#", MATCH_ALBUM_ID);
	sUriMatcher.addURI(AUTHORITY, Metadata.TABLE, MATCH_METADATA);
	// match against metadata/<Metadata._ID>
	sUriMatcher.addURI(AUTHORITY, Metadata.TABLE + "/#", MATCH_METADATA_ID);
	// match against image_cache/<ImageCache.PHOTO_ID>
	sUriMatcher.addURI(AUTHORITY, ImageCache.TABLE + "/#", MATCH_IMAGE);
	// match against image_cache/album/<Albums._ID>
	sUriMatcher.addURI(AUTHORITY, ImageCache.TABLE + "/" + Albums.TABLE + "/#",
	MATCH_ALBUM_COVER);
	}

	@Override
	public int deleteInTransaction(Uri uri, String selection, String[] selectionArgs,
	boolean callerIsSyncAdapter) {
	int match = matchUri(uri);
	selection = addIdToSelection(match, selection);
	selectionArgs = addIdToSelectionArgs(match, uri, selectionArgs);
	int deleted = 0;
	SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();
	deleted = deleteCascade(db, match, selection, selectionArgs, uri);
	return deleted;
	}

	@Override
	public String getType(Uri uri) {
	Cursor cursor = query(uri, PROJECTION_MIME_TYPE, null, null, null);
	String mimeType = null;
	if (cursor.moveToNext()) {
	mimeType = cursor.getString(0);
	}
	cursor.close();
	return mimeType;
	}

	@Override
	public Uri insertInTransaction(Uri uri, ContentValues values, boolean callerIsSyncAdapter) {
	int match = matchUri(uri);
	validateMatchTable(match);
	String table = getTableFromMatch(match, uri);
	SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();
	Uri insertedUri = null;
	long id = db.insert(table, null, values);
	if (id != -1) {
	// uri already matches the table.
	insertedUri = ContentUris.withAppendedId(uri, id);
	postNotifyUri(insertedUri);
	}
	return insertedUri;
	}

	@Override
	public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
	String sortOrder) {
	return query(uri, projection, selection, selectionArgs, sortOrder, null);
	}

	@Override
	public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
	String sortOrder, CancellationSignal cancellationSignal) {
	int match = matchUri(uri);
	selection = addIdToSelection(match, selection);
	selectionArgs = addIdToSelectionArgs(match, uri, selectionArgs);
	String table = getTableFromMatch(match, uri);
	SQLiteDatabase db = getDatabaseHelper().getReadableDatabase();
	return db.query(false, table, projection, selection, selectionArgs, null, null, sortOrder,
	null, cancellationSignal);
	}

	@Override
	public int updateInTransaction(Uri uri, ContentValues values, String selection,
	String[] selectionArgs, boolean callerIsSyncAdapter) {
	int match = matchUri(uri);
	int rowsUpdated = 0;
	SQLiteDatabase db = getDatabaseHelper().getWritableDatabase();
	if (match == MATCH_METADATA) {
	rowsUpdated = modifyMetadata(db, values);
	} else {
	selection = addIdToSelection(match, selection);
	selectionArgs = addIdToSelectionArgs(match, uri, selectionArgs);
	String table = getTableFromMatch(match, uri);
	rowsUpdated = db.update(table, values, selection, selectionArgs);
	}
	postNotifyUri(uri);
	return rowsUpdated;
	}

	public void setMockNotification(ChangeNotification notification) {
	mNotifier = notification;
	}

	protected static String addIdToSelection(int match, String selection) {
	String where;
	switch (match) {
	case MATCH_PHOTO_ID:
	case MATCH_ALBUM_ID:
	case MATCH_METADATA_ID:
	where = WHERE_ID;
	break;
	default:
	return selection;
	}
	return DatabaseUtils.concatenateWhere(selection, where);
	}

	protected static String[] addIdToSelectionArgs(int match, Uri uri, String[] selectionArgs) {
	String[] whereArgs;
	switch (match) {
	case MATCH_PHOTO_ID:
	case MATCH_ALBUM_ID:
	case MATCH_METADATA_ID:
	whereArgs = new String[] {
	uri.getPathSegments().get(1),
	};
	break;
	default:
	return selectionArgs;
	}
	return DatabaseUtils.appendSelectionArgs(selectionArgs, whereArgs);
	}

	protected static String[] addMetadataKeysToSelectionArgs(String[] selectionArgs, Uri uri) {
	List<String> segments = uri.getPathSegments();
	String[] additionalArgs = {
	segments.get(1),
	segments.get(2),
	};

	return DatabaseUtils.appendSelectionArgs(selectionArgs, additionalArgs);
	}

	protected static String getTableFromMatch(int match, Uri uri) {
	String table;
	switch (match) {
	case MATCH_PHOTO:
	case MATCH_PHOTO_ID:
	table = Photos.TABLE;
	break;
	case MATCH_ALBUM:
	case MATCH_ALBUM_ID:
	table = Albums.TABLE;
	break;
	case MATCH_METADATA:
	case MATCH_METADATA_ID:
	table = Metadata.TABLE;
	break;
	default:
	throw unknownUri(uri);
	}
	return table;
	}

	@Override
	public SQLiteOpenHelper getDatabaseHelper(Context context) {
	return new PhotoDatabase(context, DB_NAME);
	}

	private int modifyMetadata(SQLiteDatabase db, ContentValues values) {
	int rowCount;
	if (values.get(Metadata.VALUE) == null) {
	String[] selectionArgs = {
	values.getAsString(Metadata.PHOTO_ID), values.getAsString(Metadata.KEY),
	};
	rowCount = db.delete(Metadata.TABLE, WHERE_METADATA_ID, selectionArgs);
	} else {
	long rowId = db.replace(Metadata.TABLE, null, values);
	rowCount = (rowId == -1) ? 0 : 1;
	}
	return rowCount;
	}

	private int matchUri(Uri uri) {
	int match = sUriMatcher.match(uri);
	if (match == UriMatcher.NO_MATCH) {
	throw unknownUri(uri);
	}
	if (match == MATCH_IMAGE \|\| match == MATCH_ALBUM_COVER) {
	throw new IllegalArgumentException("Operation not allowed on image cache database");
	}
	return match;
	}

	@Override
	protected void notifyChange(ContentResolver resolver, Uri uri, boolean syncToNetwork) {
	if (mNotifier != null) {
	mNotifier.notifyChange(uri, syncToNetwork);
	} else {
	resolver.notifyChange(uri, null, syncToNetwork);
	}
	}

	protected static IllegalArgumentException unknownUri(Uri uri) {
	return new IllegalArgumentException("Unknown Uri format: " + uri);
	}

	protected static String nestWhere(String matchColumn, String table, String nestedWhere) {
	String query = SQLiteQueryBuilder.buildQueryString(false, table, BASE_COLUMNS_ID,
	nestedWhere, null, null, null, null);
	return matchColumn + IN + NESTED_SELECT_START + query + NESTED_SELECT_END;
	}

	protected int deleteCascade(SQLiteDatabase db, int match, String selection,
	String[] selectionArgs, Uri uri) {
	switch (match) {
	case MATCH_PHOTO:
	case MATCH_PHOTO_ID: {
	deleteCascadeMetadata(db, selection, selectionArgs);
	break;
	}
	case MATCH_ALBUM:
	case MATCH_ALBUM_ID: {
	deleteCascadePhotos(db, selection, selectionArgs);
	break;
	}
	}
	String table = getTableFromMatch(match, uri);
	int deleted = db.delete(table, selection, selectionArgs);
	if (deleted > 0) {
	postNotifyUri(uri);
	}
	return deleted;
	}

	private void deleteCascadePhotos(SQLiteDatabase db, String albumSelect,
	String[] selectArgs) {
	String photoWhere = nestWhere(Photos.ALBUM_ID, Albums.TABLE, albumSelect);
	deleteCascadeMetadata(db, photoWhere, selectArgs);
	int deleted = db.delete(Photos.TABLE, photoWhere, selectArgs);
	if (deleted > 0) {
	postNotifyUri(Photos.CONTENT_URI);
	}
	}

	private void deleteCascadeMetadata(SQLiteDatabase db, String photosSelect,
	String[] selectArgs) {
	String metadataWhere = nestWhere(Metadata.PHOTO_ID, Photos.TABLE, photosSelect);
	int deleted = db.delete(Metadata.TABLE, metadataWhere, selectArgs);
	if (deleted > 0) {
	postNotifyUri(Metadata.CONTENT_URI);
	}
	}

	private static void validateMatchTable(int match) {
	switch (match) {
	case MATCH_PHOTO:
	case MATCH_ALBUM:
	case MATCH_METADATA:
	break;
	default:
	throw new IllegalArgumentException("Operation not allowed on an existing row.");
	}
	}
	}