org.red5.io.FileKeyFrameMetaCache Maven / Gradle / Ivy

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package org.red5.io;

/*
 * RED5 Open Source Flash Server - http://code.google.com/p/red5/
 * 
 * Copyright (c) 2006-2010 by respective authors (see below). All rights reserved.
 * 
 * This library 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 2.1 of the License, or (at your option) any later 
 * version. 
 * 
 * This library 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 library; if not, write to the Free Software Foundation, Inc., 
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 
 */

import java.io.File;
//import java.io.FileOutputStream;
import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;

//import org.apache.xml.serialize.OutputFormat;
//import org.apache.xml.serialize.XMLSerializer;
import org.red5.io.flv.IKeyFrameDataAnalyzer.KeyFrameMeta;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

/**
 * File-based keyframe metadata cache.
 * 
 * @author The Red5 Project ([email protected])
 * @author Joachim Bauch ([email protected])
 */
//@SuppressWarnings("deprecation")
public class FileKeyFrameMetaCache implements IKeyFrameMetaCache {

    /**
     * Logger
     */
    private static Logger log = LoggerFactory.getLogger(FileKeyFrameMetaCache.class);

    /** {@inheritDoc} */
	public KeyFrameMeta loadKeyFrameMeta(File file) {
		String filename = file.getAbsolutePath() + ".meta";
		File metadataFile = new File(filename);
		if (!metadataFile.exists()) {
			// No such metadata
			return null;
		}
		
		Document dom;
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
		try {
			// Using factory get an instance of document builder
			DocumentBuilder db = dbf.newDocumentBuilder();
			
			// parse using builder to get DOM representation of the XML file
			dom = db.parse(filename);
			
			db.reset();
		} catch (ParserConfigurationException pce) {
			log.error("Could not parse XML file.", pce);
			return null;
		} catch (SAXException se) {
			log.error("Could not parse XML file.", se);
			return null;
		} catch (IOException ioe) {
			log.error("Could not parse XML file.", ioe);
			return null;
		}
		
		Element root = dom.getDocumentElement();
		// Check if .xml file is valid and for this .flv file
		if (!"FrameMetadata".equals(root.getNodeName())) {
			// Invalid XML
			return null;
		}
		String modified = root.getAttribute("modified");
		if (modified == null || !modified.equals(String.valueOf(file.lastModified()))) {
			// File has changed in the meantime
			return null;
		}
		if (!root.hasAttribute("duration")) {
			// Old file without duration informations
			return null;
		}
		if (!root.hasAttribute("audioOnly")) {
			// Old file without audio/video informations
			return null;
		}
		XPathFactory factory = XPathFactory.newInstance();
        XPath xpath = factory.newXPath();
        NodeList keyFrames;
        try {
            XPathExpression xexpr = xpath.compile("/FrameMetadata/KeyFrame");
            keyFrames = (NodeList) xexpr.evaluate(dom, XPathConstants.NODESET);
        } catch (XPathExpressionException err) {
        	log.error("could not compile xpath expression", err);
        	return null;
        }

        int length = keyFrames.getLength();
        if (keyFrames == null || length == 0) {
        	// File doesn't contain informations about keyframes
        	return null;
        }
        
        KeyFrameMeta result = new KeyFrameMeta();
        result.duration = Long.parseLong(root.getAttribute("duration"));
        result.positions = new long[length];
        result.timestamps = new int[length];
		for (int i=0; i