/*
* Copyright (c) 2008 Wayne Meissner
*
* This file is part of gstreamer-java.
*
* This code is free software: you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License version 3 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 3 for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with this work. If not, see <http://www.gnu.org/licenses/>.
*/
package org.gstreamer;
import java.io.File;
import org.gstreamer.lowlevel.GstNative;
import org.gstreamer.lowlevel.GstObjectAPI;
import com.sun.jna.Native;
import com.sun.jna.Pointer;
/**
* Loads and saves pipelines in an XML file
*/
public class GstXML {
private static interface LibC extends com.sun.jna.Library {
LibC INSTANCE = (LibC) Native.loadLibrary("c", LibC.class);
Pointer fopen(String path, String mode);
int fclose(Pointer fp);
}
private static interface GstXMLAPI extends GstObjectAPI {
GstObject gst_xml_new();
int gst_xml_write_file(Element element, Pointer out);
boolean gst_xml_parse_file(GstObject xml, String fname, String root);
Element gst_xml_get_element(GstObject xml, String name);
}
private static final GstXMLAPI gst = GstNative.load(GstXMLAPI.class);
private final File file;
/**
* Creates a new Gstreamer XML reader/writer
*
* @param file the file to load from/save to
*/
public GstXML(java.io.File file) {
this.file = file;
}
/**
* Loads a new {@link Element} from the XML file
*
* @param elementName the name of the element to load
*
* @return a new <tt>Element</tt>
*/
public Element loadElement(String elementName) {
GstObject xml = gst.gst_xml_new();
if (!gst.gst_xml_parse_file(xml, file.getAbsolutePath(), null)) {
throw new GstException("Could not parse " + file);
}
Element element = gst.gst_xml_get_element(xml, elementName);
if (element == null) {
throw new GstException("Could not load " + elementName);
}
return element;
}
/**
* Saves an existing pipeline to a XML file.
*
* @param element the element to save
*/
public void saveElement(Element element) {
Pointer fp = LibC.INSTANCE.fopen(file.getAbsolutePath(), "w");
if (fp == null) {
throw new GstException("Could not open " + file
+ " [errno=" + Native.getLastError() + "]");
}
gst.gst_xml_write_file(element, fp);
LibC.INSTANCE.fclose(fp);
}
}