MapFileTileSource.java

/*
 * Copyright 2013 Hannes Janetzek
 * Copyright 2013 mapsforge.org
 *
 * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
 *
 * This program is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with
 * this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.oscim.tiling.source.mapfile;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;

import org.oscim.tiling.ITileDataSource;
import org.oscim.tiling.TileSource;
import org.oscim.tiling.source.mapfile.header.MapFileHeader;
import org.oscim.tiling.source.mapfile.header.MapFileInfo;
import org.oscim.utils.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MapFileTileSource extends TileSource {
	static final Logger log = LoggerFactory.getLogger(MapFileTileSource.class);

	/**
	 * Amount of cache blocks that the index cache should store.
	 */
	private static final int INDEX_CACHE_SIZE = 64;
	private static final String READ_ONLY_MODE = "r";

	MapFileHeader fileHeader;
	MapFileInfo fileInfo;
	IndexCache databaseIndexCache;
	boolean experimental;
	File mapFile;
	RandomAccessFile mInputFile;

	public MapFileTileSource() {
		super(0, 17);
	}

	public boolean setMapFile(String filename) {
		setOption("file", filename);

		File file = new File(filename);

		if (!file.exists()) {
			return false;
		} else if (!file.isFile()) {
			return false;
		} else if (!file.canRead()) {
			return false;
		}

		return true;
	}

	@Override
	public OpenResult open() {
		if (!options.containsKey("file"))
			return new OpenResult("no map file set");

		try {
			// make sure to close any previously opened file first
			//close();

			File file = new File(options.get("file"));

			// check if the file exists and is readable
			if (!file.exists()) {
				return new OpenResult("file does not exist: " + file);
			} else if (!file.isFile()) {
				return new OpenResult("not a file: " + file);
			} else if (!file.canRead()) {
				return new OpenResult("cannot read file: " + file);
			}

			// open the file in read only mode
			mInputFile = new RandomAccessFile(file, READ_ONLY_MODE);
			long mFileSize = mInputFile.length();
			ReadBuffer mReadBuffer = new ReadBuffer(mInputFile);

			fileHeader = new MapFileHeader();
			OpenResult openResult = fileHeader.readHeader(mReadBuffer, mFileSize);

			if (!openResult.isSuccess()) {
				close();
				return openResult;
			}
			fileInfo = fileHeader.getMapFileInfo();
			mapFile = file;
			databaseIndexCache = new IndexCache(mInputFile, INDEX_CACHE_SIZE);

			experimental = fileInfo.fileVersion == 4;

			log.debug("File version: " + fileInfo.fileVersion);
			return OpenResult.SUCCESS;
		} catch (IOException e) {
			log.error(e.getMessage());
			// make sure that the file is closed
			close();
			return new OpenResult(e.getMessage());
		}
	}

	@Override
	public ITileDataSource getDataSource() {
		try {
			return new MapDatabase(this);
		} catch (IOException e) {
			log.debug(e.getMessage());
		}
		return null;
	}

	@Override
	public void close() {
		IOUtils.closeQuietly(mInputFile);
		mInputFile = null;
		fileHeader = null;
		fileInfo = null;
		mapFile = null;

		if (databaseIndexCache != null) {
			databaseIndexCache.destroy();
			databaseIndexCache = null;
		}
	}

	public MapInfo getMapInfo() {
		return fileInfo;
	}

}