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1   package org.apache.maven.plugin.internal;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.io.BufferedInputStream;
23  import java.io.ByteArrayOutputStream;
24  import java.io.File;
25  import java.io.FileInputStream;
26  import java.io.IOException;
27  import java.io.InputStream;
28  import java.io.PrintStream;
29  import java.io.Reader;
30  import java.util.ArrayList;
31  import java.util.Collection;
32  import java.util.Collections;
33  import java.util.HashMap;
34  import java.util.Iterator;
35  import java.util.List;
36  import java.util.Map;
37  import java.util.jar.JarFile;
38  import java.util.zip.ZipEntry;
39  
40  import org.apache.maven.RepositoryUtils;
41  import org.apache.maven.artifact.Artifact;
42  import org.apache.maven.classrealm.ClassRealmManager;
43  import org.apache.maven.execution.MavenSession;
44  import org.apache.maven.execution.scope.internal.MojoExecutionScopeModule;
45  import org.apache.maven.model.Plugin;
46  import org.apache.maven.monitor.logging.DefaultLog;
47  import org.apache.maven.plugin.ContextEnabled;
48  import org.apache.maven.plugin.DebugConfigurationListener;
49  import org.apache.maven.plugin.ExtensionRealmCache;
50  import org.apache.maven.plugin.InvalidPluginDescriptorException;
51  import org.apache.maven.plugin.MavenPluginManager;
52  import org.apache.maven.plugin.MavenPluginValidator;
53  import org.apache.maven.plugin.Mojo;
54  import org.apache.maven.plugin.MojoExecution;
55  import org.apache.maven.plugin.MojoNotFoundException;
56  import org.apache.maven.plugin.PluginArtifactsCache;
57  import org.apache.maven.plugin.PluginConfigurationException;
58  import org.apache.maven.plugin.PluginContainerException;
59  import org.apache.maven.plugin.PluginDescriptorCache;
60  import org.apache.maven.plugin.PluginDescriptorParsingException;
61  import org.apache.maven.plugin.PluginIncompatibleException;
62  import org.apache.maven.plugin.PluginManagerException;
63  import org.apache.maven.plugin.PluginParameterException;
64  import org.apache.maven.plugin.PluginParameterExpressionEvaluator;
65  import org.apache.maven.plugin.PluginRealmCache;
66  import org.apache.maven.plugin.PluginResolutionException;
67  import org.apache.maven.plugin.descriptor.MojoDescriptor;
68  import org.apache.maven.plugin.descriptor.Parameter;
69  import org.apache.maven.plugin.descriptor.PluginDescriptor;
70  import org.apache.maven.plugin.descriptor.PluginDescriptorBuilder;
71  import org.apache.maven.plugin.version.DefaultPluginVersionRequest;
72  import org.apache.maven.plugin.version.PluginVersionRequest;
73  import org.apache.maven.plugin.version.PluginVersionResolutionException;
74  import org.apache.maven.plugin.version.PluginVersionResolver;
75  import org.apache.maven.project.ExtensionDescriptor;
76  import org.apache.maven.project.ExtensionDescriptorBuilder;
77  import org.apache.maven.project.MavenProject;
78  import org.apache.maven.rtinfo.RuntimeInformation;
79  import org.apache.maven.session.scope.internal.SessionScopeModule;
80  import org.codehaus.plexus.DefaultPlexusContainer;
81  import org.codehaus.plexus.PlexusContainer;
82  import org.codehaus.plexus.classworlds.realm.ClassRealm;
83  import org.codehaus.plexus.component.annotations.Component;
84  import org.codehaus.plexus.component.annotations.Requirement;
85  import org.codehaus.plexus.component.composition.CycleDetectedInComponentGraphException;
86  import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
87  import org.codehaus.plexus.component.configurator.ComponentConfigurator;
88  import org.codehaus.plexus.component.configurator.ConfigurationListener;
89  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
90  import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
91  import org.codehaus.plexus.component.repository.ComponentDescriptor;
92  import org.codehaus.plexus.component.repository.exception.ComponentLifecycleException;
93  import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
94  import org.codehaus.plexus.configuration.PlexusConfiguration;
95  import org.codehaus.plexus.configuration.PlexusConfigurationException;
96  import org.codehaus.plexus.configuration.xml.XmlPlexusConfiguration;
97  import org.codehaus.plexus.logging.Logger;
98  import org.codehaus.plexus.logging.LoggerManager;
99  import org.codehaus.plexus.util.IOUtil;
100 import org.codehaus.plexus.util.ReaderFactory;
101 import org.codehaus.plexus.util.StringUtils;
102 import org.codehaus.plexus.util.xml.Xpp3Dom;
103 import org.eclipse.aether.RepositorySystemSession;
104 import org.eclipse.aether.graph.DependencyFilter;
105 import org.eclipse.aether.graph.DependencyNode;
106 import org.eclipse.aether.repository.RemoteRepository;
107 import org.eclipse.aether.util.filter.AndDependencyFilter;
108 import org.eclipse.aether.util.graph.visitor.PreorderNodeListGenerator;
109 
110 /**
111  * Provides basic services to manage Maven plugins and their mojos. This component is kept general in its design such
112  * that the plugins/mojos can be used in arbitrary contexts. In particular, the mojos can be used for ordinary build
113  * plugins as well as special purpose plugins like reports.
114  *
115  * @since 3.0
116  * @author Benjamin Bentmann
117  */
118 @Component( role = MavenPluginManager.class )
119 public class DefaultMavenPluginManager
120     implements MavenPluginManager
121 {
122 
123     /**
124      * PluginId=>ExtensionRealmCache.CacheRecord map MavenProject context value key. The map is used to ensure the same
125      * class realm is used to load build extensions and load mojos for extensions=true plugins.
126      * 
127      * @noreference this is part of internal implementation and may be changed or removed without notice
128      * @since 3.3.0
129      */
130     public static final String KEY_EXTENSIONS_REALMS = DefaultMavenPluginManager.class.getName() + "/extensionsRealms";
131 
132     @Requirement
133     private Logger logger;
134 
135     @Requirement
136     private LoggerManager loggerManager;
137 
138     @Requirement
139     private PlexusContainer container;
140 
141     @Requirement
142     private ClassRealmManager classRealmManager;
143 
144     @Requirement
145     private PluginDescriptorCache pluginDescriptorCache;
146 
147     @Requirement
148     private PluginRealmCache pluginRealmCache;
149 
150     @Requirement
151     private PluginDependenciesResolver pluginDependenciesResolver;
152 
153     @Requirement
154     private RuntimeInformation runtimeInformation;
155 
156     @Requirement
157     private ExtensionRealmCache extensionRealmCache;
158 
159     @Requirement
160     private PluginVersionResolver pluginVersionResolver;
161 
162     @Requirement
163     private PluginArtifactsCache pluginArtifactsCache;
164 
165     private ExtensionDescriptorBuilder extensionDescriptorBuilder = new ExtensionDescriptorBuilder();
166 
167     private PluginDescriptorBuilder builder = new PluginDescriptorBuilder();
168 
169     public synchronized PluginDescriptor getPluginDescriptor( Plugin plugin, List<RemoteRepository> repositories,
170                                                               RepositorySystemSession session )
171         throws PluginResolutionException, PluginDescriptorParsingException, InvalidPluginDescriptorException
172     {
173         PluginDescriptorCache.Key cacheKey = pluginDescriptorCache.createKey( plugin, repositories, session );
174 
175         PluginDescriptor pluginDescriptor = pluginDescriptorCache.get( cacheKey );
176 
177         if ( pluginDescriptor == null )
178         {
179             org.eclipse.aether.artifact.Artifact artifact =
180                 pluginDependenciesResolver.resolve( plugin, repositories, session );
181 
182             Artifact pluginArtifact = RepositoryUtils.toArtifact( artifact );
183 
184             pluginDescriptor = extractPluginDescriptor( pluginArtifact, plugin );
185 
186             pluginDescriptor.setRequiredMavenVersion( artifact.getProperty( "requiredMavenVersion", null ) );
187 
188             pluginDescriptorCache.put( cacheKey, pluginDescriptor );
189         }
190 
191         pluginDescriptor.setPlugin( plugin );
192 
193         return pluginDescriptor;
194     }
195 
196     private PluginDescriptor extractPluginDescriptor( Artifact pluginArtifact, Plugin plugin )
197         throws PluginDescriptorParsingException, InvalidPluginDescriptorException
198     {
199         PluginDescriptor pluginDescriptor = null;
200 
201         File pluginFile = pluginArtifact.getFile();
202 
203         try
204         {
205             if ( pluginFile.isFile() )
206             {
207                 JarFile pluginJar = new JarFile( pluginFile, false );
208                 try
209                 {
210                     ZipEntry pluginDescriptorEntry = pluginJar.getEntry( getPluginDescriptorLocation() );
211 
212                     if ( pluginDescriptorEntry != null )
213                     {
214                         InputStream is = pluginJar.getInputStream( pluginDescriptorEntry );
215 
216                         pluginDescriptor = parsePluginDescriptor( is, plugin, pluginFile.getAbsolutePath() );
217                     }
218                 }
219                 finally
220                 {
221                     pluginJar.close();
222                 }
223             }
224             else
225             {
226                 File pluginXml = new File( pluginFile, getPluginDescriptorLocation() );
227 
228                 if ( pluginXml.isFile() )
229                 {
230                     InputStream is = new BufferedInputStream( new FileInputStream( pluginXml ) );
231                     try
232                     {
233                         pluginDescriptor = parsePluginDescriptor( is, plugin, pluginXml.getAbsolutePath() );
234                     }
235                     finally
236                     {
237                         IOUtil.close( is );
238                     }
239                 }
240             }
241 
242             if ( pluginDescriptor == null )
243             {
244                 throw new IOException( "No plugin descriptor found at " + getPluginDescriptorLocation() );
245             }
246         }
247         catch ( IOException e )
248         {
249             throw new PluginDescriptorParsingException( plugin, pluginFile.getAbsolutePath(), e );
250         }
251 
252         MavenPluginValidator validator = new MavenPluginValidator( pluginArtifact );
253 
254         validator.validate( pluginDescriptor );
255 
256         if ( validator.hasErrors() )
257         {
258             throw new InvalidPluginDescriptorException( "Invalid plugin descriptor for " + plugin.getId() + " ("
259                 + pluginFile + ")", validator.getErrors() );
260         }
261 
262         pluginDescriptor.setPluginArtifact( pluginArtifact );
263 
264         return pluginDescriptor;
265     }
266 
267     private String getPluginDescriptorLocation()
268     {
269         return "META-INF/maven/plugin.xml";
270     }
271 
272     private PluginDescriptor parsePluginDescriptor( InputStream is, Plugin plugin, String descriptorLocation )
273         throws PluginDescriptorParsingException
274     {
275         try
276         {
277             Reader reader = ReaderFactory.newXmlReader( is );
278 
279             PluginDescriptor pluginDescriptor = builder.build( reader, descriptorLocation );
280 
281             return pluginDescriptor;
282         }
283         catch ( IOException e )
284         {
285             throw new PluginDescriptorParsingException( plugin, descriptorLocation, e );
286         }
287         catch ( PlexusConfigurationException e )
288         {
289             throw new PluginDescriptorParsingException( plugin, descriptorLocation, e );
290         }
291     }
292 
293     public MojoDescriptor getMojoDescriptor( Plugin plugin, String goal, List<RemoteRepository> repositories,
294                                              RepositorySystemSession session )
295         throws MojoNotFoundException, PluginResolutionException, PluginDescriptorParsingException,
296         InvalidPluginDescriptorException
297     {
298         PluginDescriptor pluginDescriptor = getPluginDescriptor( plugin, repositories, session );
299 
300         MojoDescriptor mojoDescriptor = pluginDescriptor.getMojo( goal );
301 
302         if ( mojoDescriptor == null )
303         {
304             throw new MojoNotFoundException( goal, pluginDescriptor );
305         }
306 
307         return mojoDescriptor;
308     }
309 
310     public void checkRequiredMavenVersion( PluginDescriptor pluginDescriptor )
311         throws PluginIncompatibleException
312     {
313         String requiredMavenVersion = pluginDescriptor.getRequiredMavenVersion();
314         if ( StringUtils.isNotBlank( requiredMavenVersion ) )
315         {
316             try
317             {
318                 if ( !runtimeInformation.isMavenVersion( requiredMavenVersion ) )
319                 {
320                     throw new PluginIncompatibleException( pluginDescriptor.getPlugin(), "The plugin "
321                         + pluginDescriptor.getId() + " requires Maven version " + requiredMavenVersion );
322                 }
323             }
324             catch ( RuntimeException e )
325             {
326                 logger.warn( "Could not verify plugin's Maven prerequisite: " + e.getMessage() );
327             }
328         }
329     }
330 
331     public synchronized void setupPluginRealm( PluginDescriptor pluginDescriptor, MavenSession session,
332                                                ClassLoader parent, List<String> imports, DependencyFilter filter )
333         throws PluginResolutionException, PluginContainerException
334     {
335         Plugin plugin = pluginDescriptor.getPlugin();
336 
337         MavenProject project = session.getCurrentProject();
338 
339         Map<String, ClassLoader> foreignImports = calcImports( project, parent, imports );
340 
341         PluginRealmCache.Key cacheKey =
342             pluginRealmCache.createKey( plugin, parent, foreignImports, filter, project.getRemotePluginRepositories(),
343                                         session.getRepositorySession() );
344 
345         PluginRealmCache.CacheRecord cacheRecord = pluginRealmCache.get( cacheKey );
346 
347         if ( cacheRecord != null )
348         {
349             pluginDescriptor.setClassRealm( cacheRecord.realm );
350             pluginDescriptor.setArtifacts( new ArrayList<Artifact>( cacheRecord.artifacts ) );
351             for ( ComponentDescriptor<?> componentDescriptor : pluginDescriptor.getComponents() )
352             {
353                 componentDescriptor.setRealm( cacheRecord.realm );
354             }
355         }
356         else
357         {
358             createPluginRealm( pluginDescriptor, session, parent, foreignImports, filter );
359 
360             cacheRecord =
361                 pluginRealmCache.put( cacheKey, pluginDescriptor.getClassRealm(), pluginDescriptor.getArtifacts() );
362         }
363 
364         pluginRealmCache.register( project, cacheKey, cacheRecord );
365     }
366 
367     private void createPluginRealm( PluginDescriptor pluginDescriptor, MavenSession session, ClassLoader parent,
368                                     Map<String, ClassLoader> foreignImports, DependencyFilter filter )
369         throws PluginResolutionException, PluginContainerException
370     {
371         Plugin plugin = pluginDescriptor.getPlugin();
372 
373         if ( plugin == null )
374         {
375             throw new IllegalArgumentException( "incomplete plugin descriptor, plugin missing" );
376         }
377 
378         Artifact pluginArtifact = pluginDescriptor.getPluginArtifact();
379 
380         if ( pluginArtifact == null )
381         {
382             throw new IllegalArgumentException( "incomplete plugin descriptor, plugin artifact missing" );
383         }
384 
385         MavenProject project = session.getCurrentProject();
386 
387         final ClassRealm pluginRealm;
388         final List<Artifact> pluginArtifacts;
389 
390         RepositorySystemSession repositorySession = session.getRepositorySession();
391         if ( plugin.isExtensions() )
392         {
393             ExtensionRealmCache.CacheRecord extensionRecord;
394             try
395             {
396                 extensionRecord = setupExtensionsRealm( project, plugin, repositorySession );
397             }
398             catch ( PluginManagerException e )
399             {
400                 // extensions realm is expected to be fully setup at this point
401                 // any exception means a problem in maven code, not a user error
402                 throw new IllegalStateException( e );
403             }
404 
405             pluginRealm = extensionRecord.realm;
406             pluginArtifacts = extensionRecord.artifacts;
407 
408             for ( ComponentDescriptor<?> componentDescriptor : pluginDescriptor.getComponents() )
409             {
410                 componentDescriptor.setRealm( pluginRealm );
411             }
412         }
413         else
414         {
415             DependencyFilter dependencyFilter = project.getExtensionDependencyFilter();
416             dependencyFilter = AndDependencyFilter.newInstance( dependencyFilter, filter );
417 
418             DependencyNode root =
419                 pluginDependenciesResolver.resolve( plugin, RepositoryUtils.toArtifact( pluginArtifact ),
420                                                     dependencyFilter, project.getRemotePluginRepositories(),
421                                                     repositorySession );
422 
423             PreorderNodeListGenerator nlg = new PreorderNodeListGenerator();
424             root.accept( nlg );
425 
426             pluginArtifacts = toMavenArtifacts( root, nlg );
427 
428             pluginRealm =
429                 classRealmManager.createPluginRealm( plugin, parent, null, foreignImports,
430                                                      toAetherArtifacts( pluginArtifacts ) );
431 
432             discoverPluginComponents( pluginRealm, plugin, pluginDescriptor );
433         }
434 
435         pluginDescriptor.setClassRealm( pluginRealm );
436         pluginDescriptor.setArtifacts( pluginArtifacts );
437     }
438 
439     private void discoverPluginComponents( final ClassRealm pluginRealm, Plugin plugin,
440                                            PluginDescriptor pluginDescriptor )
441         throws PluginContainerException
442     {
443         try
444         {
445             if ( pluginDescriptor != null )
446             {
447                 for ( ComponentDescriptor<?> componentDescriptor : pluginDescriptor.getComponents() )
448                 {
449                     componentDescriptor.setRealm( pluginRealm );
450                     container.addComponentDescriptor( componentDescriptor );
451                 }
452             }
453 
454             ( (DefaultPlexusContainer) container ).discoverComponents( pluginRealm,
455                                                                        new SessionScopeModule( container ),
456                                                                        new MojoExecutionScopeModule( container ) );
457         }
458         catch ( ComponentLookupException e )
459         {
460             throw new PluginContainerException( plugin, pluginRealm, "Error in component graph of plugin "
461                 + plugin.getId() + ": " + e.getMessage(), e );
462         }
463         catch ( CycleDetectedInComponentGraphException e )
464         {
465             throw new PluginContainerException( plugin, pluginRealm, "Error in component graph of plugin "
466                 + plugin.getId() + ": " + e.getMessage(), e );
467         }
468     }
469 
470     private List<org.eclipse.aether.artifact.Artifact> toAetherArtifacts( final List<Artifact> pluginArtifacts )
471     {
472         return new ArrayList<org.eclipse.aether.artifact.Artifact>( RepositoryUtils.toArtifacts( pluginArtifacts ) );
473     }
474 
475     private List<Artifact> toMavenArtifacts( DependencyNode root, PreorderNodeListGenerator nlg )
476     {
477         List<Artifact> artifacts = new ArrayList<Artifact>( nlg.getNodes().size() );
478         RepositoryUtils.toArtifacts( artifacts, Collections.singleton( root ), Collections.<String>emptyList(), null );
479         for ( Iterator<Artifact> it = artifacts.iterator(); it.hasNext(); )
480         {
481             Artifact artifact = it.next();
482             if ( artifact.getFile() == null )
483             {
484                 it.remove();
485             }
486         }
487         return artifacts;
488     }
489 
490     private Map<String, ClassLoader> calcImports( MavenProject project, ClassLoader parent, List<String> imports )
491     {
492         Map<String, ClassLoader> foreignImports = new HashMap<String, ClassLoader>();
493 
494         ClassLoader projectRealm = project.getClassRealm();
495         if ( projectRealm != null )
496         {
497             foreignImports.put( "", projectRealm );
498         }
499         else
500         {
501             foreignImports.put( "", classRealmManager.getMavenApiRealm() );
502         }
503 
504         if ( parent != null && imports != null )
505         {
506             for ( String parentImport : imports )
507             {
508                 foreignImports.put( parentImport, parent );
509             }
510         }
511 
512         return foreignImports;
513     }
514 
515     public <T> T getConfiguredMojo( Class<T> mojoInterface, MavenSession session, MojoExecution mojoExecution )
516         throws PluginConfigurationException, PluginContainerException
517     {
518         MojoDescriptor mojoDescriptor = mojoExecution.getMojoDescriptor();
519 
520         PluginDescriptor pluginDescriptor = mojoDescriptor.getPluginDescriptor();
521 
522         ClassRealm pluginRealm = pluginDescriptor.getClassRealm();
523 
524         if ( logger.isDebugEnabled() )
525         {
526             logger.debug( "Configuring mojo " + mojoDescriptor.getId() + " from plugin realm " + pluginRealm );
527         }
528 
529         // We are forcing the use of the plugin realm for all lookups that might occur during
530         // the lifecycle that is part of the lookup. Here we are specifically trying to keep
531         // lookups that occur in contextualize calls in line with the right realm.
532         ClassRealm oldLookupRealm = container.setLookupRealm( pluginRealm );
533 
534         ClassLoader oldClassLoader = Thread.currentThread().getContextClassLoader();
535         Thread.currentThread().setContextClassLoader( pluginRealm );
536 
537         try
538         {
539             T mojo;
540 
541             try
542             {
543                 mojo = container.lookup( mojoInterface, mojoDescriptor.getRoleHint() );
544             }
545             catch ( ComponentLookupException e )
546             {
547                 Throwable cause = e.getCause();
548                 while ( cause != null && !( cause instanceof LinkageError )
549                     && !( cause instanceof ClassNotFoundException ) )
550                 {
551                     cause = cause.getCause();
552                 }
553 
554                 if ( ( cause instanceof NoClassDefFoundError ) || ( cause instanceof ClassNotFoundException ) )
555                 {
556                     ByteArrayOutputStream os = new ByteArrayOutputStream( 1024 );
557                     PrintStream ps = new PrintStream( os );
558                     ps.println( "Unable to load the mojo '" + mojoDescriptor.getGoal() + "' in the plugin '"
559                         + pluginDescriptor.getId() + "'. A required class is missing: " + cause.getMessage() );
560                     pluginRealm.display( ps );
561 
562                     throw new PluginContainerException( mojoDescriptor, pluginRealm, os.toString(), cause );
563                 }
564                 else if ( cause instanceof LinkageError )
565                 {
566                     ByteArrayOutputStream os = new ByteArrayOutputStream( 1024 );
567                     PrintStream ps = new PrintStream( os );
568                     ps.println( "Unable to load the mojo '" + mojoDescriptor.getGoal() + "' in the plugin '"
569                         + pluginDescriptor.getId() + "' due to an API incompatibility: " + e.getClass().getName()
570                         + ": " + cause.getMessage() );
571                     pluginRealm.display( ps );
572 
573                     throw new PluginContainerException( mojoDescriptor, pluginRealm, os.toString(), cause );
574                 }
575 
576                 throw new PluginContainerException( mojoDescriptor, pluginRealm, "Unable to load the mojo '"
577                     + mojoDescriptor.getGoal() + "' (or one of its required components) from the plugin '"
578                     + pluginDescriptor.getId() + "'", e );
579             }
580 
581             if ( mojo instanceof ContextEnabled )
582             {
583                 MavenProject project = session.getCurrentProject();
584 
585                 Map<String, Object> pluginContext = session.getPluginContext( pluginDescriptor, project );
586 
587                 if ( pluginContext != null )
588                 {
589                     pluginContext.put( "project", project );
590 
591                     pluginContext.put( "pluginDescriptor", pluginDescriptor );
592 
593                     ( (ContextEnabled) mojo ).setPluginContext( pluginContext );
594                 }
595             }
596 
597             if ( mojo instanceof Mojo )
598             {
599                 Logger mojoLogger = loggerManager.getLoggerForComponent( mojoDescriptor.getImplementation() );
600                 ( (Mojo) mojo ).setLog( new DefaultLog( mojoLogger ) );
601             }
602 
603             Xpp3Dom dom = mojoExecution.getConfiguration();
604 
605             PlexusConfiguration pomConfiguration;
606 
607             if ( dom == null )
608             {
609                 pomConfiguration = new XmlPlexusConfiguration( "configuration" );
610             }
611             else
612             {
613                 pomConfiguration = new XmlPlexusConfiguration( dom );
614             }
615 
616             ExpressionEvaluator expressionEvaluator = new PluginParameterExpressionEvaluator( session, mojoExecution );
617 
618             populatePluginFields( mojo, mojoDescriptor, pluginRealm, pomConfiguration, expressionEvaluator );
619 
620             return mojo;
621         }
622         finally
623         {
624             Thread.currentThread().setContextClassLoader( oldClassLoader );
625             container.setLookupRealm( oldLookupRealm );
626         }
627     }
628 
629     private void populatePluginFields( Object mojo, MojoDescriptor mojoDescriptor, ClassRealm pluginRealm,
630                                        PlexusConfiguration configuration, ExpressionEvaluator expressionEvaluator )
631         throws PluginConfigurationException
632     {
633         ComponentConfigurator configurator = null;
634 
635         String configuratorId = mojoDescriptor.getComponentConfigurator();
636 
637         if ( StringUtils.isEmpty( configuratorId ) )
638         {
639             configuratorId = "basic";
640         }
641 
642         try
643         {
644             // TODO: could the configuration be passed to lookup and the configurator known to plexus via the descriptor
645             // so that this method could entirely be handled by a plexus lookup?
646             configurator = container.lookup( ComponentConfigurator.class, configuratorId );
647 
648             ConfigurationListener listener = new DebugConfigurationListener( logger );
649 
650             ValidatingConfigurationListener validator =
651                 new ValidatingConfigurationListener( mojo, mojoDescriptor, listener );
652 
653             logger.debug( "Configuring mojo '" + mojoDescriptor.getId() + "' with " + configuratorId
654                 + " configurator -->" );
655 
656             configurator.configureComponent( mojo, configuration, expressionEvaluator, pluginRealm, validator );
657 
658             logger.debug( "-- end configuration --" );
659 
660             Collection<Parameter> missingParameters = validator.getMissingParameters();
661             if ( !missingParameters.isEmpty() )
662             {
663                 if ( "basic".equals( configuratorId ) )
664                 {
665                     throw new PluginParameterException( mojoDescriptor, new ArrayList<Parameter>( missingParameters ) );
666                 }
667                 else
668                 {
669                     /*
670                      * NOTE: Other configurators like the map-oriented one don't call into the listener, so do it the
671                      * hard way.
672                      */
673                     validateParameters( mojoDescriptor, configuration, expressionEvaluator );
674                 }
675             }
676         }
677         catch ( ComponentConfigurationException e )
678         {
679             String message = "Unable to parse configuration of mojo " + mojoDescriptor.getId();
680             if ( e.getFailedConfiguration() != null )
681             {
682                 message += " for parameter " + e.getFailedConfiguration().getName();
683             }
684             message += ": " + e.getMessage();
685 
686             throw new PluginConfigurationException( mojoDescriptor.getPluginDescriptor(), message, e );
687         }
688         catch ( ComponentLookupException e )
689         {
690             throw new PluginConfigurationException( mojoDescriptor.getPluginDescriptor(),
691                                                     "Unable to retrieve component configurator " + configuratorId
692                                                         + " for configuration of mojo " + mojoDescriptor.getId(), e );
693         }
694         catch ( NoClassDefFoundError e )
695         {
696             ByteArrayOutputStream os = new ByteArrayOutputStream( 1024 );
697             PrintStream ps = new PrintStream( os );
698             ps.println( "A required class was missing during configuration of mojo " + mojoDescriptor.getId() + ": "
699                 + e.getMessage() );
700             pluginRealm.display( ps );
701 
702             throw new PluginConfigurationException( mojoDescriptor.getPluginDescriptor(), os.toString(), e );
703         }
704         catch ( LinkageError e )
705         {
706             ByteArrayOutputStream os = new ByteArrayOutputStream( 1024 );
707             PrintStream ps = new PrintStream( os );
708             ps.println( "An API incompatibility was encountered during configuration of mojo " + mojoDescriptor.getId()
709                 + ": " + e.getClass().getName() + ": " + e.getMessage() );
710             pluginRealm.display( ps );
711 
712             throw new PluginConfigurationException( mojoDescriptor.getPluginDescriptor(), os.toString(), e );
713         }
714         finally
715         {
716             if ( configurator != null )
717             {
718                 try
719                 {
720                     container.release( configurator );
721                 }
722                 catch ( ComponentLifecycleException e )
723                 {
724                     logger.debug( "Failed to release mojo configurator - ignoring." );
725                 }
726             }
727         }
728     }
729 
730     private void validateParameters( MojoDescriptor mojoDescriptor, PlexusConfiguration configuration,
731                                      ExpressionEvaluator expressionEvaluator )
732         throws ComponentConfigurationException, PluginParameterException
733     {
734         if ( mojoDescriptor.getParameters() == null )
735         {
736             return;
737         }
738 
739         List<Parameter> invalidParameters = new ArrayList<Parameter>();
740 
741         for ( Parameter parameter : mojoDescriptor.getParameters() )
742         {
743             if ( !parameter.isRequired() )
744             {
745                 continue;
746             }
747 
748             Object value = null;
749 
750             PlexusConfiguration config = configuration.getChild( parameter.getName(), false );
751             if ( config != null )
752             {
753                 String expression = config.getValue( null );
754 
755                 try
756                 {
757                     value = expressionEvaluator.evaluate( expression );
758 
759                     if ( value == null )
760                     {
761                         value = config.getAttribute( "default-value", null );
762                     }
763                 }
764                 catch ( ExpressionEvaluationException e )
765                 {
766                     String msg =
767                         "Error evaluating the expression '" + expression + "' for configuration value '"
768                             + configuration.getName() + "'";
769                     throw new ComponentConfigurationException( configuration, msg, e );
770                 }
771             }
772 
773             if ( value == null && ( config == null || config.getChildCount() <= 0 ) )
774             {
775                 invalidParameters.add( parameter );
776             }
777         }
778 
779         if ( !invalidParameters.isEmpty() )
780         {
781             throw new PluginParameterException( mojoDescriptor, invalidParameters );
782         }
783     }
784 
785     public void releaseMojo( Object mojo, MojoExecution mojoExecution )
786     {
787         if ( mojo != null )
788         {
789             try
790             {
791                 container.release( mojo );
792             }
793             catch ( ComponentLifecycleException e )
794             {
795                 String goalExecId = mojoExecution.getGoal();
796 
797                 if ( mojoExecution.getExecutionId() != null )
798                 {
799                     goalExecId += " {execution: " + mojoExecution.getExecutionId() + "}";
800                 }
801 
802                 logger.debug( "Error releasing mojo for " + goalExecId, e );
803             }
804         }
805     }
806 
807     public ExtensionRealmCache.CacheRecord setupExtensionsRealm( MavenProject project, Plugin plugin,
808                                                                  RepositorySystemSession session )
809         throws PluginManagerException
810     {
811         @SuppressWarnings( "unchecked" )
812         Map<String, ExtensionRealmCache.CacheRecord> pluginRealms =
813             (Map<String, ExtensionRealmCache.CacheRecord>) project.getContextValue( KEY_EXTENSIONS_REALMS );
814         if ( pluginRealms == null )
815         {
816             pluginRealms = new HashMap<String, ExtensionRealmCache.CacheRecord>();
817             project.setContextValue( KEY_EXTENSIONS_REALMS, pluginRealms );
818         }
819 
820         final String pluginKey = plugin.getId();
821 
822         ExtensionRealmCache.CacheRecord extensionRecord = pluginRealms.get( pluginKey );
823         if ( extensionRecord != null )
824         {
825             return extensionRecord;
826         }
827 
828         final List<RemoteRepository> repositories = project.getRemotePluginRepositories();
829 
830         // resolve plugin version as necessary
831         if ( plugin.getVersion() == null )
832         {
833             PluginVersionRequest versionRequest = new DefaultPluginVersionRequest( plugin, session, repositories );
834             try
835             {
836                 plugin.setVersion( pluginVersionResolver.resolve( versionRequest ).getVersion() );
837             }
838             catch ( PluginVersionResolutionException e )
839             {
840                 throw new PluginManagerException( plugin, e.getMessage(), e );
841             }
842         }
843 
844         // resolve plugin artifacts
845         List<Artifact> artifacts;
846         PluginArtifactsCache.Key cacheKey = pluginArtifactsCache.createKey( plugin, null, repositories, session );
847         PluginArtifactsCache.CacheRecord recordArtifacts;
848         try
849         {
850             recordArtifacts = pluginArtifactsCache.get( cacheKey );
851         }
852         catch ( PluginResolutionException e )
853         {
854             throw new PluginManagerException( plugin, e.getMessage(), e );
855         }
856         if ( recordArtifacts != null )
857         {
858             artifacts = recordArtifacts.artifacts;
859         }
860         else
861         {
862             try
863             {
864                 artifacts = resolveExtensionArtifacts( plugin, repositories, session );
865                 recordArtifacts = pluginArtifactsCache.put( cacheKey, artifacts );
866             }
867             catch ( PluginResolutionException e )
868             {
869                 pluginArtifactsCache.put( cacheKey, e );
870                 pluginArtifactsCache.register( project, cacheKey, recordArtifacts );
871                 throw new PluginManagerException( plugin, e.getMessage(), e );
872             }
873         }
874         pluginArtifactsCache.register( project, cacheKey, recordArtifacts );
875 
876         // create and cache extensions realms
877         final ExtensionRealmCache.Key extensionKey = extensionRealmCache.createKey( artifacts );
878         extensionRecord = extensionRealmCache.get( extensionKey );
879         if ( extensionRecord == null )
880         {
881             ClassRealm extensionRealm = classRealmManager.createExtensionRealm( plugin,
882                                                                                 toAetherArtifacts( artifacts ) );
883 
884             // TODO figure out how to use the same PluginDescriptor when running mojos
885 
886             PluginDescriptor pluginDescriptor = null;
887             if ( plugin.isExtensions() && !artifacts.isEmpty() )
888             {
889                 // ignore plugin descriptor parsing errors at this point
890                 // these errors will reported during calculation of project build execution plan
891                 try
892                 {
893                     pluginDescriptor = extractPluginDescriptor( artifacts.get( 0 ), plugin );
894                 }
895                 catch ( PluginDescriptorParsingException e )
896                 {
897                     // ignore, see above
898                 }
899                 catch ( InvalidPluginDescriptorException e )
900                 {
901                     // ignore, see above
902                 }
903             }
904 
905             discoverPluginComponents( extensionRealm, plugin, pluginDescriptor );
906 
907             ExtensionDescriptor extensionDescriptor = null;
908             Artifact extensionArtifact = artifacts.get( 0 );
909             try
910             {
911                 extensionDescriptor = extensionDescriptorBuilder.build( extensionArtifact.getFile() );
912             }
913             catch ( IOException e )
914             {
915                 String message = "Invalid extension descriptor for " + plugin.getId() + ": " + e.getMessage();
916                 if ( logger.isDebugEnabled() )
917                 {
918                     logger.error( message, e );
919                 }
920                 else
921                 {
922                     logger.error( message );
923                 }
924             }
925             extensionRecord = extensionRealmCache.put( extensionKey, extensionRealm, extensionDescriptor, artifacts );
926         }
927         extensionRealmCache.register( project, extensionKey, extensionRecord );
928         pluginRealms.put( pluginKey, extensionRecord );
929 
930         return extensionRecord;
931     }
932 
933     private List<Artifact> resolveExtensionArtifacts( Plugin extensionPlugin, List<RemoteRepository> repositories,
934                                                       RepositorySystemSession session )
935         throws PluginResolutionException
936     {
937         DependencyNode root = pluginDependenciesResolver.resolve( extensionPlugin, null, null, repositories, session );
938         PreorderNodeListGenerator nlg = new PreorderNodeListGenerator();
939         root.accept( nlg );
940         return toMavenArtifacts( root, nlg );
941     }
942 
943 }