Compile the generated sources into the expected target directory

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/JavacCompiler.java

@@ -134,6 +134,7 @@ public void finished(TaskEvent e) {
 		for (Entry<IContainer, List<ICompilationUnit>> outputSourceSet : outputSourceMapping.entrySet()) {
 			// Configure Javac to generate the class files in a mapped temporary location
 			var outputDir = JavacClassFile.getMappedTempOutput(outputSourceSet.getKey()).toFile();
+			javacListener.setOutputDir(outputSourceSet.getKey());
 			JavacUtils.configureJavacContext(javacContext, this.compilerConfig, javaProject, outputDir, true);
 			JavaCompiler javac = new JavaCompiler(javacContext) {
 				boolean isInGeneration = false;
@@ -197,6 +198,7 @@ public int errorCount() {
 				// TODO fail
 				ILog.get().error("compilation failed", e);
 			}
+
 			for (int i = 0; i < sourceUnits.length; i++) {
 				ICompilationUnit in = sourceUnits[i];
 				CompilationResult result = new CompilationResult(in, i, sourceUnits.length, Integer.MAX_VALUE);

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/JavacTaskListener.java

@@ -13,6 +13,11 @@
 
 package org.eclipse.jdt.internal.javac;
 
+import java.io.File;
+import java.io.IOException;
+import java.net.URI;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -26,10 +31,16 @@
 import javax.tools.JavaFileObject;
 
 import org.eclipse.core.resources.IContainer;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.resources.IFolder;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.ILog;
+import org.eclipse.core.runtime.IPath;
 import org.eclipse.jdt.internal.compiler.ClassFile;
 import org.eclipse.jdt.internal.compiler.IProblemFactory;
 import org.eclipse.jdt.internal.compiler.env.ICompilationUnit;
+import org.eclipse.jdt.internal.compiler.util.SuffixConstants;
 
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.CompilationUnitTree;
@@ -48,13 +59,15 @@
 import com.sun.tools.javac.code.Type.UnknownType;
 import com.sun.tools.javac.tree.JCTree.JCClassDecl;
 import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
-import com.sun.tools.javac.tree.JCTree.JCModuleDecl;
 import com.sun.tools.javac.tree.JCTree.JCIdent;
+import com.sun.tools.javac.tree.JCTree.JCModuleDecl;
 
 public class JavacTaskListener implements TaskListener {
 	private Map<ICompilationUnit, IContainer> sourceOutputMapping = new HashMap<>();
 	private Map<ICompilationUnit, JavacCompilationResult> results = new HashMap<>();
 	private UnusedProblemFactory problemFactory;
+	private JavacConfig config;
+	private IContainer outputDir;
 	private final Map<JavaFileObject, ICompilationUnit> fileObjectToCUMap;
 	private static final Set<String> PRIMITIVE_TYPES = new HashSet<String>(Arrays.asList(
 		"byte",
@@ -71,6 +84,7 @@ public class JavacTaskListener implements TaskListener {
 
 	public JavacTaskListener(JavacConfig config, Map<IContainer, List<ICompilationUnit>> outputSourceMapping,
 			IProblemFactory problemFactory, Map<JavaFileObject, ICompilationUnit> fileObjectToCUMap) {
+		this.config = config;
 		this.problemFactory = new UnusedProblemFactory(problemFactory, config.compilerOptions());
 		this.fileObjectToCUMap = fileObjectToCUMap;
 		for (Entry<IContainer, List<ICompilationUnit>> entry : outputSourceMapping.entrySet()) {
@@ -81,7 +95,18 @@ public JavacTaskListener(JavacConfig config, Map<IContainer, List<ICompilationUn
 
 	@Override
 	public void finished(TaskEvent e) {
-		if (e.getKind() == TaskEvent.Kind.ANALYZE) {
+		if (e.getKind() == TaskEvent.Kind.GENERATE) {
+			final JavaFileObject file = e.getSourceFile();
+			final ICompilationUnit cu = this.fileObjectToCUMap.get(file);
+			if (cu == null && e.getTypeElement() instanceof ClassSymbol clazz && isGeneratedSource(file)) {
+				try {
+					// Write the class files for the generated sources.
+					writeClassFile(clazz);
+				} catch (CoreException e1) {
+					// TODO
+				}
+			}
+		} else if (e.getKind() == TaskEvent.Kind.ANALYZE) {
 			final JavaFileObject file = e.getSourceFile();
 			final ICompilationUnit cu = this.fileObjectToCUMap.get(file);
 			if (cu == null) {
@@ -251,6 +276,73 @@ private void recordTypeHierarchy(ClassSymbol classSymbol) {
 		}
 	}
 
+	private boolean isGeneratedSource(JavaFileObject file) {
+		List<IContainer> generatedSourcePaths = this.config.originalConfig().generatedSourcePaths();
+		if (generatedSourcePaths == null || generatedSourcePaths.isEmpty()) {
+			return false;
+		}
+
+		URI uri = file.toUri();
+		if (uri != null && uri.getPath() != null) {
+			File ioFile = new File(uri.getPath());
+			Path fileIOPath = ioFile.toPath();
+			return generatedSourcePaths.stream().anyMatch(container -> {
+				IPath location = container.getRawLocation();
+				if (location != null) {
+					Path locationIOPath = location.toPath();
+					return fileIOPath.startsWith(locationIOPath);
+				}
+				return false;
+			});
+		}
+		return false;
+	}
+
+	private void writeClassFile(ClassSymbol clazz) throws CoreException {
+		if (this.outputDir == null) {
+			return;
+		}
+
+		String qualifiedName = clazz.flatName().toString().replace('.', '/');
+		IPath filePath = new org.eclipse.core.runtime.Path(qualifiedName);
+		IContainer fileFolder = this.outputDir;
+		if (filePath.segmentCount() > 1) {
+			fileFolder = createFolder(filePath.removeLastSegments(1), this.outputDir);
+			filePath = new org.eclipse.core.runtime.Path(filePath.lastSegment());
+		}
+
+		IFile classFile = fileFolder.getFile(filePath.addFileExtension(SuffixConstants.EXTENSION_class));
+		File tmpJavacClassFile = JavacClassFile.computeMappedTempClassFile(this.outputDir, qualifiedName);
+		if (tmpJavacClassFile == null || !tmpJavacClassFile.exists()) {
+			return;
+		}
+
+		try {
+			byte[] bytes = Files.readAllBytes(tmpJavacClassFile.toPath());
+			classFile.write(bytes, true, true, false, null);
+			tmpJavacClassFile.delete();
+		} catch (IOException e) {
+			// ignore
+		}
+	}
+
+	private IContainer createFolder(IPath packagePath, IContainer outputFolder) throws CoreException {
+		if (packagePath.isEmpty()) {
+			return outputFolder;
+		}
+
+		IFolder folder = outputFolder.getFolder(packagePath);
+		if (!folder.exists()) {
+			createFolder(packagePath.removeLastSegments(1), outputFolder);
+			folder.create(IResource.FORCE | IResource.DERIVED, true, null);
+		}
+		return folder;
+	}
+
+	public void setOutputDir(IContainer outputDir) {
+		this.outputDir = outputDir;
+	}
+
 	public Map<ICompilationUnit, JavacCompilationResult> getResults() {
 		return this.results;
 	}