Provide a Tycho Workspace Reader

pom.xml

@@ -58,7 +58,7 @@
 		</developer>
 	</developers>
 	<prerequisites>
-		<maven>3.6.3</maven>
+		<maven>3.8.6</maven>
 	</prerequisites>
 
 	<groupId>org.eclipse.tycho</groupId>
@@ -84,7 +84,7 @@
 		<jxpathVersion>1.3</jxpathVersion>
 		<pluginToolsVersion>3.6.4</pluginToolsVersion>
 		<jgit-version>6.1.0.202203080745-r</jgit-version>
-		<maven-version>3.8.5</maven-version>
+		<maven-version>3.8.6</maven-version>
 		<!-- NOTE: when updating surefire version, double-check Import-Package statements generated by bnd-maven-plugin and possibly adapt instructions in various bnd.bnd files -->
 		<!-- Stick to 3.0.0-M5 because of https://github.com/eclipse/tycho/issues/879 / https://issues.apache.org/jira/projects/SUREFIRE/issues/SUREFIRE-2072 -->
 		<surefire-version>3.0.0-M5</surefire-version>

tycho-core/src/main/java/org/eclipse/tycho/core/maven/TychoWorkspaceReader.java

@@ -0,0 +1,163 @@
+/*******************************************************************************
+ * Copyright (c) 2022 Christoph Läubrich and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *    Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tycho.core.maven;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Optional;
+
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.model.Model;
+import org.apache.maven.model.io.ModelWriter;
+import org.apache.maven.plugin.LegacySupport;
+import org.apache.maven.project.MavenProject;
+import org.apache.maven.repository.internal.MavenWorkspaceReader;
+import org.codehaus.plexus.component.annotations.Component;
+import org.codehaus.plexus.component.annotations.Requirement;
+import org.codehaus.plexus.logging.Logger;
+import org.eclipse.aether.RepositorySystemSession;
+import org.eclipse.aether.artifact.Artifact;
+import org.eclipse.aether.repository.LocalRepository;
+import org.eclipse.aether.repository.WorkspaceReader;
+import org.eclipse.aether.repository.WorkspaceRepository;
+import org.eclipse.sisu.equinox.EquinoxServiceFactory;
+import org.eclipse.tycho.ArtifactDescriptor;
+import org.eclipse.tycho.ArtifactKey;
+import org.eclipse.tycho.MavenDependencyDescriptor;
+import org.eclipse.tycho.ReactorProject;
+import org.eclipse.tycho.TychoConstants;
+import org.eclipse.tycho.artifacts.DependencyArtifacts;
+import org.eclipse.tycho.core.osgitools.DefaultReactorProject;
+import org.eclipse.tycho.core.utils.TychoProjectUtils;
+import org.eclipse.tycho.p2.resolver.facade.P2ResolverFactory;
+
+@Component(role = WorkspaceReader.class, hint = "TychoWorkspaceReader")
+public class TychoWorkspaceReader implements WorkspaceReader, MavenWorkspaceReader {
+
+    private WorkspaceRepository repository;
+
+    @Requirement
+    private LegacySupport legacySupport;
+
+    @Requirement
+    private EquinoxServiceFactory equinox;
+
+    @Requirement
+    private Logger logger;
+
+    @Requirement
+    private ModelWriter modelWriter;
+
+    public TychoWorkspaceReader() {
+        repository = new WorkspaceRepository("tycho", null);
+    }
+
+    @Override
+    public WorkspaceRepository getRepository() {
+        return repository;
+    }
+
+    @Override
+    public File findArtifact(Artifact artifact) {
+        if ("pom".equals(artifact.getExtension())) {
+            if (artifact.getGroupId().startsWith(TychoConstants.P2_GROUPID_PREFIX)) {
+                //TODO Maven should actually call the findModel instead see: https://issues.apache.org/jira/browse/MNG-7496
+                logger.debug("Find the pom for " + artifact);
+                File pomFile = getFileForArtifact(artifact);
+                if (pomFile.isFile()) {
+                    return pomFile;
+                }
+                Model findModel = findModel(artifact);
+                if (findModel != null) {
+                    try {
+                        pomFile.getParentFile().mkdirs();
+                        modelWriter.write(pomFile, new HashMap<String, Object>(), findModel);
+                        return pomFile;
+                    } catch (IOException e) {
+                        logger.debug("Can't write model!", e);
+                    }
+                }
+            }
+            return null;
+        }
+        if (artifact.getGroupId().startsWith(TychoConstants.P2_GROUPID_PREFIX)) {
+            File cachedFile = getFileForArtifact(artifact);
+            if (cachedFile.isFile()) {
+                return cachedFile;
+            }
+        }
+
+        MavenSession session = legacySupport.getSession();
+        if (session != null) {
+            MavenProject currentProject = session.getCurrentProject();
+            ReactorProject reactorProject = DefaultReactorProject.adapt(currentProject);
+
+            Optional<DependencyArtifacts> dependencyMetadata = TychoProjectUtils
+                    .getOptionalDependencyArtifacts(reactorProject);
+            if (dependencyMetadata.isPresent()) {
+                P2ResolverFactory factory = this.equinox.getService(P2ResolverFactory.class);
+                logger.debug("Attempt to resolve " + artifact + " for project " + currentProject + " ...");
+                for (ArtifactDescriptor descriptor : dependencyMetadata.get().getArtifacts()) {
+                    MavenDependencyDescriptor dependencyDescriptor = factory.resolveDependencyDescriptor(descriptor);
+                    if (dependencyDescriptor != null) {
+                        if (dependencyDescriptor.getGroupId().equals(artifact.getGroupId())
+                                && dependencyDescriptor.getArtifactId().equals(artifact.getArtifactId())) {
+                            ArtifactKey artifactKey = descriptor.getKey();
+                            if (dependencyDescriptor.getVersion().equals(artifact.getVersion())
+                                    || artifactKey.getVersion().equals(artifact.getVersion())) {
+                                //we have a match!
+                                return descriptor.getLocation(true);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        return null;
+    }
+
+    protected File getFileForArtifact(Artifact artifact) {
+        RepositorySystemSession repositorySession = legacySupport.getRepositorySession();
+        LocalRepository localRepository = repositorySession.getLocalRepository();
+        File basedir = localRepository.getBasedir();
+        File cachedFile = new File(basedir, "p2/osgi/bundle/" + artifact.getArtifactId() + "/" + artifact.getVersion()
+                + "/" + artifact.getArtifactId() + "-" + artifact.getVersion() + "." + artifact.getExtension());
+        return cachedFile;
+    }
+
+    @Override
+    public List<String> findVersions(Artifact artifact) {
+        return Collections.emptyList();
+    }
+
+    @Override
+    public Model findModel(Artifact artifact) {
+        if (artifact.getGroupId().startsWith(TychoConstants.P2_GROUPID_PREFIX)) {
+            logger.debug("Find the model for: " + artifact);
+            Model model = new Model();
+            model.setModelVersion("4.0.0");
+            model.setArtifactId(artifact.getArtifactId());
+            model.setGroupId(artifact.getGroupId());
+            model.setVersion(artifact.getVersion());
+            model.setPackaging(artifact.getProperty("packaging", null));
+            if (model.getPackaging() == null) {
+                model.setPackaging(
+                        artifact.getGroupId().substring(TychoConstants.P2_GROUPID_PREFIX.length()).replace('.', '-'));
+            }
+            return model;
+        }
+        return null;
+    }
+
+}

tycho-core/src/main/java/org/eclipse/tycho/core/utils/TychoProjectUtils.java

@@ -12,6 +12,7 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 import org.eclipse.tycho.ReactorProject;
 import org.eclipse.tycho.TychoConstants;
@@ -42,6 +43,12 @@ public static DependencyArtifacts getDependencyArtifacts(ReactorProject project)
         return resolvedDependencies;
     }
 
+    public static Optional<DependencyArtifacts> getOptionalDependencyArtifacts(ReactorProject project) {
+        DependencyArtifacts resolvedDependencies = (DependencyArtifacts) project
+                .getContextValue(TychoConstants.CTX_DEPENDENCY_ARTIFACTS);
+        return Optional.ofNullable(resolvedDependencies);
+    }
+
     /**
      * Returns the {@link TargetPlatformConfiguration} instance associated with the given project.
      * 

tycho-extras/tycho-p2-extras-plugin/src/test/java/org/eclipse/tycho/plugins/p2/extras/MirrorMojoTest.java

@@ -15,14 +15,18 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.FileVisitResult;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.SimpleFileVisitor;
+import java.nio.file.attribute.BasicFileAttributes;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 
-import org.apache.commons.io.FileUtils;
 import org.apache.maven.artifact.repository.ArtifactRepository;
 import org.apache.maven.execution.MavenSession;
 import org.apache.maven.plugin.LegacySupport;
@@ -47,12 +51,38 @@ protected void setUp() throws Exception {
         MavenProject project = projects.get(0);
         initLegacySupport(projects, project);
         mirrorDestinationDir = new File(project.getFile().getParent(), "target/repository").getCanonicalFile();
-        FileUtils.deleteDirectory(mirrorDestinationDir);
+        if (mirrorDestinationDir.exists()) {
+            deleteFolder(mirrorDestinationDir.toPath());
+        }
         mirrorMojo = lookupMojo("mirror", project.getFile());
         setVariableValueToObject(mirrorMojo, "destination", mirrorDestinationDir);
         setVariableValueToObject(mirrorMojo, "project", project);
     }
 
+    private static void deleteFolder(final Path path) throws IOException {
+        Files.walkFileTree(path, new SimpleFileVisitor<Path>() {
+            @Override
+            public FileVisitResult visitFile(final Path file, final BasicFileAttributes attrs) throws IOException {
+                Files.delete(file);
+                return FileVisitResult.CONTINUE;
+            }
+
+            @Override
+            public FileVisitResult visitFileFailed(final Path file, final IOException e) {
+                return FileVisitResult.TERMINATE;
+            }
+
+            @Override
+            public FileVisitResult postVisitDirectory(final Path dir, final IOException e) throws IOException {
+                if (e != null) {
+                    return FileVisitResult.TERMINATE;
+                }
+                Files.delete(dir);
+                return FileVisitResult.CONTINUE;
+            }
+        });
+    }
+
     @Override
     protected void tearDown() throws Exception {
         // this is needed because the DefaultEquinoxEmbedder plexus component