/*

  * This file is part of dependency-check-core.

  *

  * Licensed under the Apache License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  *

  * Copyright (c) 2014 Jeremy Long. All Rights Reserved.

  */

 package org.owasp.dependencycheck.data.nuget;

 import java.io.InputStream;

 import javax.xml.parsers.DocumentBuilderFactory;

 import javax.xml.xpath.XPath;

 import javax.xml.xpath.XPathConstants;

 import javax.xml.xpath.XPathFactory;

 import org.w3c.dom.Document;

 import org.w3c.dom.Node;

 /**

  * Parse a Nuspec file using XPath.

  *

  * @author willstranathan

  */

 public class XPathNuspecParser implements NuspecParser {

     /**

      * Gets the string value of a node or null if it's not present

      *

      * @param n the node to test

      * @return the string content of the node, or null if the node itself is null

      */

     private String getOrNull(Node n) {

         if (n != null) {

             return n.getTextContent();

         } else {

             return null;

         }

     }

     /**

      * Parse an input stream and return the resulting {@link NugetPackage}.

      *

      * @param stream the input stream to parse

      * @return the populated bean

      * @throws NuspecParseException when an exception occurs

      */

     @Override

     public NugetPackage parse(InputStream stream) throws NuspecParseException {

         try {

             final Document d = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(stream);

             final XPath xpath = XPathFactory.newInstance().newXPath();

             final NugetPackage nuspec = new NugetPackage();

             if (xpath.evaluate("/package/metadata/id", d, XPathConstants.NODE) == null

                     || xpath.evaluate("/package/metadata/version", d, XPathConstants.NODE) == null

                     || xpath.evaluate("/package/metadata/authors", d, XPathConstants.NODE) == null

                     || xpath.evaluate("/package/metadata/description", d, XPathConstants.NODE) == null) {

                 throw new NuspecParseException("Invalid Nuspec format");

             }

             nuspec.setId(xpath.evaluate("/package/metadata/id", d));

             nuspec.setVersion(xpath.evaluate("/package/metadata/version", d));

             nuspec.setAuthors(xpath.evaluate("/package/metadata/authors", d));

             nuspec.setOwners(getOrNull((Node) xpath.evaluate("/package/metadata/owners",  d, XPathConstants.NODE)));

             nuspec.setLicenseUrl(getOrNull((Node) xpath.evaluate("/package/metadata/licenseUrl",  d, XPathConstants.NODE)));

             nuspec.setTitle(getOrNull((Node) xpath.evaluate("/package/metadata/title",  d, XPathConstants.NODE)));

             return nuspec;

         } catch (Exception e) {

             throw new NuspecParseException("Unable to parse nuspec", e);

         }

     }

 }