org.xwiki.xar.internal.XarUtils.java Source code

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Here is the source code for org.xwiki.xar.internal.XarUtils.java

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/*
 * See the NOTICE file distributed with this work for additional
 * information regarding copyright ownership.
 *
 * This 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 software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.xwiki.xar.internal;

import java.io.InputStream;
import java.util.Locale;

import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;

import org.apache.commons.lang3.LocaleUtils;
import org.xwiki.model.EntityType;
import org.xwiki.model.internal.reference.DefaultSymbolScheme;
import org.xwiki.model.internal.reference.RelativeStringEntityReferenceResolver;
import org.xwiki.model.reference.EntityReference;
import org.xwiki.model.reference.LocalDocumentReference;
import org.xwiki.xar.XarException;
import org.xwiki.xar.internal.model.XarDocumentModel;
import org.xwiki.xml.stax.StAXUtils;

/**
 * @version $Id: 5a22efe6a9ae616a997e928913f3a162de599ce1 $
 * @since 5.4M1
 */
public final class XarUtils {
    public static final RelativeStringEntityReferenceResolver RESOLVER = new RelativeStringEntityReferenceResolver(
            new DefaultSymbolScheme());

    private static final XMLInputFactory XML_INPUT_FACTORY = XMLInputFactory.newInstance();

    private XarUtils() {
        // Utility class
    }

    /**
     * Extract {@link LocalDocumentReference} from a XAR document XML stream.
     * 
     * @param documentStream the stream to parse
     * @return the reference extracted from the stream
     * @throws XarException when failing to parse the document stream
     * @since 5.4M1
     */
    public static LocalDocumentReference getReference(InputStream documentStream) throws XarException {
        XMLStreamReader xmlReader;
        try {
            xmlReader = XML_INPUT_FACTORY.createXMLStreamReader(documentStream);
        } catch (XMLStreamException e) {
            throw new XarException("Failed to create a XML read", e);
        }

        EntityReference reference = null;
        Locale locale = null;

        String legacySpace = null;
        String legacyPage = null;

        try {
            // <xwikidoc>

            xmlReader.nextTag();

            xmlReader.require(XMLStreamReader.START_ELEMENT, null, XarDocumentModel.ELEMENT_DOCUMENT);

            // Reference
            String referenceString = xmlReader.getAttributeValue(null,
                    XarDocumentModel.ATTRIBUTE_DOCUMENT_REFERENCE);
            if (referenceString != null) {
                reference = RESOLVER.resolve(referenceString, EntityType.DOCUMENT);
            }

            // Locale
            String localeString = xmlReader.getAttributeValue(null, XarDocumentModel.ATTRIBUTE_DOCUMENT_LOCALE);
            if (localeString != null) {
                if (localeString.isEmpty()) {
                    locale = Locale.ROOT;
                } else {
                    locale = LocaleUtils.toLocale(localeString);
                }
            }

            // Legacy fallback
            if (reference == null || locale == null) {
                for (xmlReader.nextTag(); xmlReader.isStartElement(); xmlReader.nextTag()) {
                    String elementName = xmlReader.getLocalName();

                    if (XarDocumentModel.ELEMENT_NAME.equals(elementName)) {
                        if (reference == null) {
                            legacyPage = xmlReader.getElementText();

                            if (legacySpace != null && locale != null) {
                                break;
                            }
                        } else if (locale != null) {
                            break;
                        }
                    } else if (XarDocumentModel.ELEMENT_SPACE.equals(elementName)) {
                        if (reference == null) {
                            legacySpace = xmlReader.getElementText();

                            if (legacyPage != null && locale != null) {
                                break;
                            }
                        } else if (locale != null) {
                            break;
                        }
                    } else if (XarDocumentModel.ELEMENT_LOCALE.equals(elementName)) {
                        if (locale == null) {
                            String value = xmlReader.getElementText();
                            if (value.length() == 0) {
                                locale = Locale.ROOT;
                            } else {
                                locale = LocaleUtils.toLocale(value);
                            }
                        }

                        if (reference != null || (legacySpace != null && legacyPage != null)) {
                            break;
                        }
                    } else {
                        StAXUtils.skipElement(xmlReader);
                    }
                }
            }
        } catch (XMLStreamException e) {
            throw new XarException("Failed to parse document", e);
        } finally {
            try {
                xmlReader.close();
            } catch (XMLStreamException e) {
                throw new XarException("Failed to close XML reader", e);
            }
        }

        if (reference == null) {
            if (legacySpace == null) {
                throw new XarException("Missing space element");
            }
            if (legacyPage == null) {
                throw new XarException("Missing page element");
            }

            reference = new LocalDocumentReference(legacySpace, legacyPage);
        }

        if (locale == null) {
            throw new XarException("Missing locale element");
        }

        return new LocalDocumentReference(reference, locale);
    }
}