Cache source bundle generation in local Maven repository

tycho-core/src/main/java/org/eclipse/m2e/pde/target/shared/MavenBundleWrapper.java

@@ -397,4 +397,50 @@ public static void transferJarEntries(File source, Manifest manifest, File targe
     public static boolean isValidSourceManifest(Manifest manifest) {
         return manifest != null && manifest.getMainAttributes().getValue(ECLIPSE_SOURCE_BUNDLE_HEADER) != null;
     }
+
+    /**
+     * Creates or returns a cached Eclipse source bundle from a source JAR file. The resulting
+     * bundle will have proper Eclipse-SourceBundle manifest headers. The cached file is stored
+     * alongside the original source file with "-eclipse-source" suffix.
+     * 
+     * @param sourceFile
+     *            the original source JAR file (e.g., xyz-source.jar)
+     * @param manifest
+     *            the manifest to use (will be modified with source bundle metadata)
+     * @param symbolicName
+     *            the bundle symbolic name of the host bundle
+     * @param bundleVersion
+     *            the version of the host bundle
+     * @return the cached eclipse source bundle file
+     * @throws IOException
+     *             if reading/writing files fails
+     */
+    public static File getEclipseSourceBundle(File sourceFile, Manifest manifest, String symbolicName,
+            String bundleVersion) throws IOException {
+        // Create the cached file name: xyz-source.jar -> xyz-eclipse-source.jar
+        String sourceName = sourceFile.getName();
+        String eclipseSourceName;
+        if (sourceName.endsWith(".jar")) {
+            eclipseSourceName = sourceName.substring(0, sourceName.length() - 4) + "-eclipse-source.jar";
+        } else {
+            eclipseSourceName = sourceName + "-eclipse-source";
+        }
+        File eclipseSourceFile = new File(sourceFile.getParentFile(), eclipseSourceName);
+        Path eclipseSourcePath = eclipseSourceFile.toPath();
+        Path sourceFilePath = sourceFile.toPath();
+
+        // Check if cached file exists and is up-to-date
+        if (!isOutdated(eclipseSourcePath, sourceFilePath)) {
+            return eclipseSourceFile;
+        }
+
+        // Generate new eclipse source bundle
+        addSourceBundleMetadata(manifest, symbolicName, bundleVersion);
+        transferJarEntries(sourceFile, manifest, eclipseSourceFile);
+
+        // Set the last modified time to match source file for cache validation
+        Files.setLastModifiedTime(eclipseSourcePath, Files.getLastModifiedTime(sourceFilePath));
+
+        return eclipseSourceFile;
+    }
 }

tycho-core/src/main/java/org/eclipse/tycho/core/resolver/MavenTargetDefinitionContent.java

@@ -432,11 +432,9 @@ private static void stripRuntimeOSGiHeaders(Manifest manifest, String symbolicNa
     private IInstallableUnit generateSourceBundle(String symbolicName, String bundleVersion, Manifest manifest,
             File sourceFile, IArtifactFacade sourceArtifact, MavenLogger logger) throws IOException, BundleException {
         stripRuntimeOSGiHeaders(manifest, symbolicName, bundleVersion, logger);
-        File tempFile = File.createTempFile("tycho_wrapped_source", ".jar");
-        tempFile.deleteOnExit();
-        MavenBundleWrapper.addSourceBundleMetadata(manifest, symbolicName, bundleVersion);
-        MavenBundleWrapper.transferJarEntries(sourceFile, manifest, tempFile);
-        return publish(BundlesAction.createBundleDescription(tempFile), tempFile, sourceArtifact);
+        File eclipseSourceFile = MavenBundleWrapper.getEclipseSourceBundle(sourceFile, manifest, symbolicName,
+                bundleVersion);
+        return publish(BundlesAction.createBundleDescription(eclipseSourceFile), eclipseSourceFile, sourceArtifact);
 
     }
 

tycho-core/src/test/java/org/eclipse/m2e/pde/target/shared/MavenBundleWrapperTest.java

@@ -0,0 +1,169 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Christoph Läubrich and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * https://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.m2e.pde.target.shared;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.util.jar.Attributes;
+import java.util.jar.JarFile;
+import java.util.jar.JarOutputStream;
+import java.util.jar.Manifest;
+import java.util.zip.ZipEntry;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+/**
+ * Tests for {@link MavenBundleWrapper} functionality.
+ */
+public class MavenBundleWrapperTest {
+
+    @Rule
+    public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+    @Test
+    public void testGetEclipseSourceBundle_createsNewBundle() throws Exception {
+        // Create a source JAR file
+        File sourceFile = temporaryFolder.newFile("test-source.jar");
+        createSourceJar(sourceFile);
+
+        Manifest manifest = new Manifest();
+        File result = MavenBundleWrapper.getEclipseSourceBundle(sourceFile, manifest, "com.example.bundle", "1.0.0");
+
+        assertNotNull(result);
+        assertTrue("Eclipse source bundle should exist", result.exists());
+        assertEquals("test-source-eclipse-source.jar", result.getName());
+        assertEquals(sourceFile.getParentFile(), result.getParentFile());
+
+        // Verify manifest headers
+        try (JarFile jar = new JarFile(result)) {
+            Manifest resultManifest = jar.getManifest();
+            assertNotNull(resultManifest);
+            Attributes attrs = resultManifest.getMainAttributes();
+            assertEquals("com.example.bundle.source", attrs.getValue("Bundle-SymbolicName"));
+            assertEquals("1.0.0", attrs.getValue("Bundle-Version"));
+            assertTrue(attrs.getValue("Eclipse-SourceBundle").contains("com.example.bundle"));
+        }
+    }
+
+    @Test
+    public void testGetEclipseSourceBundle_returnsCache() throws Exception {
+        // Create a source JAR file
+        File sourceFile = temporaryFolder.newFile("cached-source.jar");
+        createSourceJar(sourceFile);
+
+        Manifest manifest1 = new Manifest();
+        File result1 = MavenBundleWrapper.getEclipseSourceBundle(sourceFile, manifest1, "com.example.bundle", "1.0.0");
+
+        // Remember modification time
+        long firstModTime = result1.lastModified();
+
+        // Wait a bit to ensure timestamp would be different if regenerated
+        Thread.sleep(100);
+
+        // Call again - should return cached version
+        Manifest manifest2 = new Manifest();
+        File result2 = MavenBundleWrapper.getEclipseSourceBundle(sourceFile, manifest2, "com.example.bundle", "1.0.0");
+
+        assertEquals(result1.getAbsolutePath(), result2.getAbsolutePath());
+        assertEquals("Cache should be reused, modification time should be unchanged", firstModTime,
+                result2.lastModified());
+    }
+
+    @Test
+    public void testGetEclipseSourceBundle_regeneratesWhenSourceChanged() throws Exception {
+        // Create a source JAR file
+        File sourceFile = temporaryFolder.newFile("changing-source.jar");
+        createSourceJar(sourceFile);
+
+        Manifest manifest1 = new Manifest();
+        File result1 = MavenBundleWrapper.getEclipseSourceBundle(sourceFile, manifest1, "com.example.bundle", "1.0.0");
+        long firstSize = result1.length();
+
+        // Modify the source file
+        Thread.sleep(100); // Ensure different timestamp
+        createSourceJar(sourceFile, "additional content");
+
+        // Update source file timestamp to be newer
+        sourceFile.setLastModified(System.currentTimeMillis());
+
+        Manifest manifest2 = new Manifest();
+        File result2 = MavenBundleWrapper.getEclipseSourceBundle(sourceFile, manifest2, "com.example.bundle", "1.0.0");
+
+        assertEquals(result1.getAbsolutePath(), result2.getAbsolutePath());
+        // The file should be regenerated (different size due to different content)
+        assertTrue("Regenerated bundle should have different size", result2.length() != firstSize);
+    }
+
+    @Test
+    public void testIsOutdated_returnsTrueForMissingCache() throws Exception {
+        File sourceFile = temporaryFolder.newFile("source.jar");
+        File cacheFile = new File(temporaryFolder.getRoot(), "cache.jar");
+
+        assertTrue("Missing cache file should be outdated",
+                MavenBundleWrapper.isOutdated(cacheFile.toPath(), sourceFile.toPath()));
+    }
+
+    @Test
+    public void testIsOutdated_returnsFalseForUpToDateCache() throws Exception {
+        File sourceFile = temporaryFolder.newFile("source.jar");
+        File cacheFile = temporaryFolder.newFile("cache.jar");
+
+        // Set cache to be same timestamp as source
+        cacheFile.setLastModified(sourceFile.lastModified());
+
+        assertFalse("Cache with same timestamp should not be outdated",
+                MavenBundleWrapper.isOutdated(cacheFile.toPath(), sourceFile.toPath()));
+    }
+
+    @Test
+    public void testIsOutdated_returnsTrueWhenSourceNewer() throws Exception {
+        File sourceFile = temporaryFolder.newFile("source.jar");
+        File cacheFile = temporaryFolder.newFile("cache.jar");
+
+        // Set source to be newer than cache
+        Thread.sleep(100);
+        sourceFile.setLastModified(System.currentTimeMillis());
+        cacheFile.setLastModified(sourceFile.lastModified() - 1000);
+
+        assertTrue("Cache should be outdated when source is newer",
+                MavenBundleWrapper.isOutdated(cacheFile.toPath(), sourceFile.toPath()));
+    }
+
+    private void createSourceJar(File file) throws IOException {
+        createSourceJar(file, null);
+    }
+
+    private void createSourceJar(File file, String additionalContent) throws IOException {
+        Manifest manifest = new Manifest();
+        manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+        try (JarOutputStream jos = new JarOutputStream(new FileOutputStream(file), manifest)) {
+            // Add a dummy source file
+            jos.putNextEntry(new ZipEntry("com/example/Test.java"));
+            String content = "package com.example;\npublic class Test {}";
+            if (additionalContent != null) {
+                content += "\n// " + additionalContent;
+            }
+            jos.write(content.getBytes());
+            jos.closeEntry();
+        }
+    }
+}