Merge pull request #6181 from hackbar/database-downgrade

Android: Handle a database downgrade.

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/model/GameDatabase.java

@@ -78,6 +78,7 @@ public final class GameDatabase extends SQLiteOpenHelper
 			+ KEY_DB_ID + TYPE_PRIMARY + SEPARATOR
 			+ KEY_FOLDER_PATH + TYPE_STRING + CONSTRAINT_UNIQUE + ")";
 
+	private static final String SQL_DELETE_FOLDERS = "DROP TABLE IF EXISTS " + TABLE_NAME_FOLDERS;
 	private static final String SQL_DELETE_GAMES = "DROP TABLE IF EXISTS " + TABLE_NAME_GAMES;
 
 	public GameDatabase(Context context)
@@ -91,23 +92,29 @@ public void onCreate(SQLiteDatabase database)
 	{
 		Log.debug("[GameDatabase] GameDatabase - Creating database...");
 
-		Log.verbose("[GameDatabase] Executing SQL: " + SQL_CREATE_GAMES);
-		database.execSQL(SQL_CREATE_GAMES);
+		execSqlAndLog(database, SQL_CREATE_GAMES);
+		execSqlAndLog(database, SQL_CREATE_FOLDERS);
+	}
+
+	@Override
+	public void onDowngrade(SQLiteDatabase database, int oldVersion, int newVersion)
+	{
+		Log.verbose("[GameDatabase] Downgrades not supporting, clearing databases..");
+		execSqlAndLog(database, SQL_DELETE_FOLDERS);
+		execSqlAndLog(database, SQL_CREATE_FOLDERS);
 
-		Log.verbose("[GameDatabase] Executing SQL: " + SQL_CREATE_FOLDERS);
-		database.execSQL(SQL_CREATE_FOLDERS);
+		execSqlAndLog(database, SQL_DELETE_GAMES);
+		execSqlAndLog(database, SQL_CREATE_GAMES);
 	}
 
 	@Override
 	public void onUpgrade(SQLiteDatabase database, int oldVersion, int newVersion)
 	{
 		Log.info("[GameDatabase] Upgrading database from schema version " + oldVersion + " to " + newVersion);
 
-		Log.verbose("[GameDatabase] Executing SQL: " + SQL_DELETE_GAMES);
-		database.execSQL(SQL_DELETE_GAMES);
-
-		Log.verbose("[GameDatabase] Executing SQL: " + SQL_CREATE_GAMES);
-		database.execSQL(SQL_CREATE_GAMES);
+		// Delete all the games
+		execSqlAndLog(database, SQL_DELETE_GAMES);
+		execSqlAndLog(database, SQL_CREATE_GAMES);
 
 		Log.verbose("[GameDatabase] Re-scanning library with new schema.");
 		scanLibrary(database);
@@ -283,4 +290,10 @@ public void call(Subscriber<? super Cursor> subscriber)
 			}
 		});
 	}
+
+	private void execSqlAndLog(SQLiteDatabase database, String sql)
+	{
+		Log.verbose("[GameDatabase] Executing SQL: " + sql);
+		database.execSQL(sql);
+	}
 }