package org.apache.maven.shared.runtime;

 /*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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.

  */

 import java.io.IOException;

 import java.net.MalformedURLException;

 import java.net.URL;

 import java.net.URLConnection;

 import java.util.Enumeration;

 import java.util.HashSet;

 import java.util.Set;

 import java.util.jar.JarEntry;

 import java.util.jar.JarInputStream;

 import org.codehaus.plexus.util.IOUtil;

 /**

  * Provides various methods of applying Maven runtime visitors.

  * 

  * @author <a href="mailto:markh@apache.org">Mark Hobson</a>

  * @version $Id: MavenRuntimeVisitorUtils.java 1341433 2012-05-22 12:13:18Z markh $

  * @see MavenRuntimeVisitor

  */

 final class MavenRuntimeVisitorUtils

 {

     // constants --------------------------------------------------------------

     /**

      * The path to Maven's metadata directory.

      */

     private static final String MAVEN_PATH = "META-INF/maven";

     /**

      * The path elements of a Maven project properties file, where {@code null} is a wildcard.

      */

     private static final String[] PROPERTIES_PATH_TOKENS =

         new String[] { "META-INF", "maven", null, null, "pom.properties" };

     /**

      * The path elements of a Maven project XML file, where {@code null} is a wildcard.

      */

     private static final String[] XML_PATH_TOKENS = new String[] { "META-INF", "maven", null, null, "pom.xml" };

     /**

      * The path element index of a Maven project properties/XML file that contains the project group id.

      */

     private static final int GROUP_ID_TOKEN_INDEX = 2;

     /**

      * The path element index of a Maven project properties/XML file that contains the project artifact id.

      */

     private static final int ARTIFACT_ID_TOKEN_INDEX = 3;

     // constructors -----------------------------------------------------------

     /**

      * {@code MavenRuntimeVisitorUtils} is not intended to be instantiated.

      */

     private MavenRuntimeVisitorUtils()

     {

         throw new AssertionError();

     }

     // public methods ---------------------------------------------------------

     /**

      * Invokes the specified visitor on all Maven projects found within the specified class loader.

      * 

      * @param classLoader

      *            the class loader to introspect

      * @param visitor

      *            the visitor to invoke

      * @throws MavenRuntimeException

      *             if an error occurs visiting the projects

      */

     public static void accept( ClassLoader classLoader, MavenRuntimeVisitor visitor )

         throws MavenRuntimeException

     {

         Enumeration<URL> urls;

         try

         {

             urls = classLoader.getResources( MAVEN_PATH );

         }

         catch ( IOException exception )

         {

             throw new MavenRuntimeException( "Cannot obtain Maven metadata from class loader: " + classLoader,

                                              exception );

         }

         Set<String> visitedProjectProperties = new HashSet<String>();

         Set<String> visitedProjectXML = new HashSet<String>();

         while ( urls.hasMoreElements() )

         {

             URL url = urls.nextElement();

             acceptURL( url, visitor, visitedProjectProperties, visitedProjectXML );

         }

     }

     /**

      * Invokes the specified visitor on the specified class's Maven project.

      * 

      * @param klass

      *            the class to introspect

      * @param visitor

      *            the visitor to invoke

      * @throws MavenRuntimeException

      *             if an error occurs visiting the projects

      */

     public static void accept( Class<?> klass, MavenRuntimeVisitor visitor )

         throws MavenRuntimeException

     {

         try

         {

             URL baseURL = ClassUtils.getBaseURL( klass );

             URL url = new URL( baseURL, MAVEN_PATH );

             acceptURL( url, visitor, new HashSet<String>(), new HashSet<String>() );

         }

         catch ( MalformedURLException exception )

         {

             throw new MavenRuntimeException( "Cannot obtain URL for class: " + klass.getName(), exception );

         }

     }

     /**

      * Invokes the specified visitor on the specified URL's Maven project.

      * 

      * @param url

      *            the URL to introspect

      * @param visitor

      *            the visitor to invoke

      * @throws MavenRuntimeException

      *             if an error occurs visiting the projects

      */

     public static void accept( URL url, MavenRuntimeVisitor visitor )

         throws MavenRuntimeException

     {

         try

         {

             if ( "jar".equals( url.getProtocol() ) )

             {

                 url = getJarFileURL( url );

             }

             URL baseURL = getJarEntryURL( url, "" );

             URL mavenURL = new URL( baseURL, MAVEN_PATH );

             acceptURL( mavenURL, visitor, new HashSet<String>(), new HashSet<String>() );

         }

         catch ( MalformedURLException exception )

         {

             throw new MavenRuntimeException( "Cannot obtain URL for Jar: " + url, exception );

         }

     }

     // private methods --------------------------------------------------------

     /**

      * Invokes the specified visitor on all Maven projects found within the specified Maven metadata URL.

      * 

      * @param url

      *            the URL of the Maven metadata directory to introspect

      * @param visitor

      *            the visitor to invoke

      * @param visitedProjectProperties

      *            the ids of projects' properties that have been visited

      * @param visitedProjectXML

      *            the ids of projects' XML that have been visited

      * @throws MavenRuntimeException

      *             if an error occurs visiting the projects

      */

     private static void acceptURL( URL url, MavenRuntimeVisitor visitor, Set<String> visitedProjectProperties,

                                    Set<String> visitedProjectXML ) throws MavenRuntimeException

     {

         if ( "jar".equals( url.getProtocol() ) )

         {

             URL jarURL;

             try

             {

                 jarURL = getJarFileURL( url );

             }

             catch ( MalformedURLException exception )

             {

                 throw new MavenRuntimeException( "Cannot obtain Jar file URL for URL: " + url, exception );

             }

             acceptJar( jarURL, visitor, visitedProjectProperties, visitedProjectXML );

         }

     }

     /**

      * Invokes the specified visitor on all Maven projects found within the specified Jar URL.

      * 

      * @param url

      *            the Jar URL to introspect

      * @param visitor

      *            the visitor to invoke

      * @param visitedProjectProperties

      *            the ids of projects' properties that have been visited

      * @param visitedProjectXML

      *            the ids of projects' XML that have been visited

      * @throws MavenRuntimeException

      *             if an error occurs visiting the projects

      */

     private static void acceptJar( URL url, MavenRuntimeVisitor visitor, Set<String> visitedProjectProperties,

                                    Set<String> visitedProjectXML ) throws MavenRuntimeException

     {

         JarInputStream in = null;

         try

         {

             URLConnection connection = url.openConnection();

             connection.setUseCaches( false );

             in = new JarInputStream( connection.getInputStream() );

             JarEntry entry;

             while ( ( entry = in.getNextJarEntry() ) != null )

             {

                 acceptJarEntry( url, entry, visitor, visitedProjectProperties, visitedProjectXML );

             }

         }

         catch ( IOException exception )

         {

             throw new MavenRuntimeException( "Cannot read jar", exception );

         }

         finally

         {

             IOUtil.close( in );

         }

     }

     /**

      * Invokes the specified visitor on the specified Jar entry if it corresponds to a Maven project XML or properties

      * file.

      * 

      * @param jarURL

      *            a URL to the Jar file for this entry

      * @param entry

      *            the Jar entry to introspect

      * @param visitor

      *            the visitor to invoke

      * @param visitedProjectProperties

      *            the ids of projects' properties that have been visited

      * @param visitedProjectXML

      *            the ids of projects' XML that have been visited

      * @throws MavenRuntimeException

      *             if an error occurs visiting the projects

      */

     private static void acceptJarEntry( URL jarURL, JarEntry entry, MavenRuntimeVisitor visitor,

                                         Set<String> visitedProjectProperties, Set<String> visitedProjectXML )

         throws MavenRuntimeException

     {

         String name = entry.getName();

         try

         {

             URL url = getJarEntryURL( jarURL, entry.getName() );

             if ( isProjectPropertiesPath( name ) )

             {

                 String projectId = getProjectId( name );

                 if ( !visitedProjectProperties.contains( projectId ) )

                 {

                     visitor.visitProjectProperties( url );

                     visitedProjectProperties.add( projectId );

                 }

             }

             else if ( isProjectXMLPath( name ) )

             {

                 String projectId = getProjectId( name );

                 if ( !visitedProjectXML.contains( projectId ) )

                 {

                     visitor.visitProjectXML( url );

                     visitedProjectXML.add( projectId );

                 }

             }

         }

         catch ( MalformedURLException exception )

         {

             throw new MavenRuntimeException( "Cannot read jar entry", exception );

         }

     }

     /**

      * Gets the underlying Jar file URL for the specified Jar entry URL.

      * 

      * @param url

      *            the Jar entry URL

      * @return the Jar file URL

      * @throws MalformedURLException

      *             if an error occurs deriving the Jar file URL

      */

     private static URL getJarFileURL( URL url ) throws MalformedURLException

     {

         if ( !"jar".equals( url.getProtocol() ) )

         {

             return url;

         }

         String path = url.getPath();

         int index = path.indexOf( "!/" );

         if ( index != -1 )

         {

             path = path.substring( 0, index );

         }

         return new URL( path );

     }

     private static URL getJarEntryURL( URL jarURL, String entryName ) throws MalformedURLException

     {

         return new URL( "jar:" + jarURL + "!/" + entryName );

     }

     /**

      * Gets a unique project identifier for the specified Maven project properties/XML file.

      * 

      * @param path

      *            the path to a Maven project properties/XML file

      * @return the unique project identifier

      */

     private static String getProjectId( String path )

     {

         String[] tokens = path.split( "/" );

         String groupId = tokens[GROUP_ID_TOKEN_INDEX];

         String artifactId = tokens[ARTIFACT_ID_TOKEN_INDEX];

         return groupId + ":" + artifactId;

     }

     /**

      * Gets whether the specified path represents a Maven project properties file.

      * 

      * @param path

      *            the path to examine

      * @return {@code true} if the specified path represents a Maven project properties file

      */

     private static boolean isProjectPropertiesPath( String path )

     {

         return matches( PROPERTIES_PATH_TOKENS, path.split( "/" ) );

     }

     /**

      * Gets whether the specified path represents a Maven project XML file.

      * 

      * @param path

      *            the path to examine

      * @return {@code true} if the specified path represents a Maven project XML file

      */

     private static boolean isProjectXMLPath( String path )

     {

         return matches( XML_PATH_TOKENS, path.split( "/" ) );

     }

     /**

      * Gets whether the specified string arrays are equal, with wildcard support.

      * 

      * @param matchTokens

      *            the string tokens to match, where {@code null} represents a wildcard

      * @param tokens

      *            the string tokens to test

      * @return {@code true} if the {@code tokens} array equals the {@code matchTokens}, treating any {@code null}

      *         {@code matchTokens} values as wildcards

      */

     private static boolean matches( String[] matchTokens, String[] tokens )

     {

         if ( tokens.length != matchTokens.length )

         {

             return false;

         }

         for ( int i = 0; i < tokens.length; i++ )

         {

             if ( matchTokens[i] != null && !tokens[i].equals( matchTokens[i] ) )

             {

                 return false;

             }

         }

         return true;

     }

 }