Allow basedir in MavenExecutionContext and project-specific MavenImpl

This allows to read and set project-specific properties that can be
passed to the Maven request and used for
further executions.

Covers parts of eclipse-m2e#666 and
progress towards eclipse-m2e#546

org.eclipse.m2e.core.tests/resources/projects/dotMvn/child/pom.xml

@@ -0,0 +1,6 @@
+<project>
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>org.eclipse.m2e.tests.projects</groupId>
+	<artifactId>simplePomOK</artifactId>
+	<version>1</version>
+</project>

org.eclipse.m2e.core.tests/src/org/eclipse/m2e/core/MavenBugsTest.java

@@ -26,11 +26,13 @@
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.FileLocator;
 import org.eclipse.core.runtime.NullProgressMonitor;
+import org.eclipse.m2e.core.internal.MavenPluginActivator;
 import org.eclipse.m2e.core.project.IMavenProjectFacade;
 import org.eclipse.m2e.core.project.MavenProjectInfo;
 import org.eclipse.m2e.core.project.ProjectImportConfiguration;
 import org.eclipse.m2e.tests.common.AbstractMavenProjectTestCase;
 import org.junit.After;
+import org.junit.Assert;
 import org.junit.Test;
 
 
@@ -78,5 +80,29 @@ public void testMNG6530() throws Exception {
     } finally {
       FileUtils.deleteDirectory(tempDirectory);
     }
+  }
+
+	@Test
+	public void testMultiModuleProjectDirectoryChild() throws Exception {
+		IProject project = createExisting("simple", "resources/projects/dotMvn/", false);
+		waitForJobsToComplete(monitor);
+		IMavenProjectFacade facade = MavenPluginActivator.getDefault().getMavenProjectManagerImpl().create(project.getFile("child/pom.xml"),
+			true, monitor);
+		Assert.assertNotNull(facade);
+		File[] multiModuleDirectory = new File[] { null }; 
+		facade.getMaven().execute((context, monitor) -> multiModuleDirectory[0] = context.getExecutionRequest().getMultiModuleProjectDirectory(), null);
+		assertEquals(project.getLocation().toFile(), multiModuleDirectory[0]);
+  }
+
+	@Test
+	public void testMultiModuleProjectDirectorySimple() throws Exception {
+		IProject project = createExisting("hierarchyWithDotMVN", "resources/projects/simplePomOK", true);
+		waitForJobsToComplete(monitor);
+		IMavenProjectFacade facade = MavenPluginActivator.getDefault().getMavenProjectManagerImpl().create(project,
+			monitor);
+		Assert.assertNotNull(facade);
+		File[] multiModuleDirectory = new File[] { null }; 
+		facade.getMaven().execute((context, monitor) -> multiModuleDirectory[0] = context.getExecutionRequest().getMultiModuleProjectDirectory(), null);
+		assertEquals(project.getLocation().toFile(), multiModuleDirectory[0]);
   }
 }

org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/embedder/MavenExecutionContext.java

@@ -15,6 +15,7 @@
 
 import static org.eclipse.m2e.core.internal.M2EUtils.copyProperties;
 
+import java.io.File;
 import java.util.ArrayDeque;
 import java.util.Collections;
 import java.util.Deque;
@@ -66,13 +67,17 @@ public class MavenExecutionContext implements IMavenExecutionContext {
   // TODO maybe delegate to parent context
   private Map<String, Object> context;
 
-  public MavenExecutionContext(MavenImpl maven) {
+  private final File basedir;
+
+  public MavenExecutionContext(MavenImpl maven, File basedir) {
     this.maven = maven;
+    this.basedir = basedir == null ? null : (basedir.isDirectory() ? basedir : basedir.getParentFile());
   }
 
   MavenExecutionContext(MavenImpl maven, MavenExecutionRequest request) {
     this.maven = maven;
     this.request = request;
+    this.basedir = request.getBaseDirectory() != null ? new File(request.getBaseDirectory()) : null;
   }
 
   @Override
@@ -99,6 +104,7 @@ protected MavenExecutionRequest newExecutionRequest() throws CoreException {
     if(request == null) {
       request = maven.createExecutionRequest();
     }
+    request.setMultiModuleProjectDirectory(MavenImpl.computeMultiModuleProjectDirectory(basedir));
 
     return request;
   }

org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/embedder/MavenImpl.java

@@ -174,7 +174,7 @@
 
 
 @Component(service = {IMaven.class, IMavenConfigurationChangeListener.class})
-public class MavenImpl implements IMaven, IMavenConfigurationChangeListener {
+public class MavenImpl implements IMaven, IMavenConfigurationChangeListener, Cloneable {
   private static final Logger log = LoggerFactory.getLogger(MavenImpl.class);
 
   /**
@@ -204,6 +204,8 @@ public class MavenImpl implements IMaven, IMavenConfigurationChangeListener {
   /** Last modified timestamp of cached user settings */
   private long settingsTimestamp;
 
+  private File basedir;
+
   MavenExecutionRequest createExecutionRequest() throws CoreException {
     MavenExecutionRequest request = new DefaultMavenExecutionRequest();
 
@@ -242,6 +244,10 @@ MavenExecutionRequest createExecutionRequest() throws CoreException {
     request.setGlobalChecksumPolicy(mavenConfiguration.getGlobalChecksumPolicy());
     // the right way to disable snapshot update
     // request.setUpdateSnapshots(false);
+    if(basedir != null) {
+      request.setBaseDirectory(basedir);
+      request.setMultiModuleProjectDirectory(computeMultiModuleProjectDirectory(basedir));
+    }
     return request;
   }
 
@@ -665,7 +671,7 @@ public Artifact resolve(String groupId, String artifactId, String version, Strin
   private IMavenExecutionContext context() {
     MavenExecutionContext context = MavenExecutionContext.getThreadContext();
     if(context == null) {
-      context = new MavenExecutionContext(this);
+      context = createExecutionContext();
     }
     return context;
   }
@@ -1250,7 +1256,7 @@ public void execute(MavenProject project, MojoExecution execution, IProgressMoni
 
   @Override
   public MavenExecutionContext createExecutionContext() {
-    return new MavenExecutionContext(this);
+    return new MavenExecutionContext(this, basedir);
   }
 
   @Override
@@ -1308,4 +1314,17 @@ public static File computeMultiModuleProjectDirectory(File file) {
     return basedir;
   }
 
+  public MavenImpl cloneForBasedir(File basedir) {
+    try {
+      MavenImpl res = (MavenImpl) clone();
+      res.basedir = basedir;
+      // TODO: more customization may be needed, more fields cleared, maybe in the end no
+      // need to start from a clone at all...
+      // TODO? What about getExecutionContext() that's tied to the thread and not to this?
+      return res;
+    } catch(CloneNotSupportedException ex) {
+      // unexpected, let's just crash
+      throw new RuntimeException(ex);
+    }
+  }
 }

org.eclipse.m2e.core/src/org/eclipse/m2e/core/internal/project/registry/MavenProjectFacade.java

@@ -41,6 +41,7 @@
 import org.eclipse.m2e.core.embedder.ArtifactRef;
 import org.eclipse.m2e.core.embedder.ArtifactRepositoryRef;
 import org.eclipse.m2e.core.embedder.IMaven;
+import org.eclipse.m2e.core.internal.embedder.MavenImpl;
 import org.eclipse.m2e.core.lifecyclemapping.model.IPluginExecutionMetadata;
 import org.eclipse.m2e.core.project.IMavenProjectFacade;
 import org.eclipse.m2e.core.project.MavenProjectUtils;
@@ -108,6 +109,8 @@ public class MavenProjectFacade implements IMavenProjectFacade, Serializable {
 
   private transient Map<String, Object> sessionProperties;
 
+  private IMaven maven;
+
   public MavenProjectFacade(ProjectRegistryManager manager, IFile pom, MavenProject mavenProject,
       ResolverConfiguration resolverConfiguration) {
     this.manager = manager;
@@ -532,7 +535,10 @@ public List<MojoExecution> getExecutionPlan(String lifecycle, IProgressMonitor m
 
   @Override
   public IMaven getMaven() {
-    // TODO: if project has Maven customization (such as a .mvn, MAVEN_OPTS...)
-    return MavenPlugin.getMaven();
+    if(maven == null) {
+      File basedir = pomFile != null ? (pomFile.isDirectory() ? pomFile : pomFile.getParentFile()) : null;
+      maven = ((MavenImpl) MavenPlugin.getMaven()).cloneForBasedir(basedir);
+    }
+    return maven;
   }
 }