Improve link feature to provide links for all decompilers

src/main/java/com/heliosdecompiler/transformerapi/StandardTransformers.java

@@ -92,7 +92,7 @@ public static Decompiler<?> valueOf(String engineName) {
          *
          * Gets the default decompiler (currently Vineflower)
          * @since 4.2.1
-         * @return the default decompiler (currently Vineflower)
+         * @return the default decompiler
          */
         public static Decompiler<?> getDefault() {
             return valueOf("");

src/main/java/com/heliosdecompiler/transformerapi/common/AbstractResultSaver.java

@@ -16,13 +16,15 @@
 
 package com.heliosdecompiler.transformerapi.common;
 
+import org.jetbrains.java.decompiler.main.extern.IResultSaver;
+
 import java.util.HashMap;
 import java.util.Map;
 import java.util.jar.Manifest;
 
 import jd.core.DecompilationResult;
 
-public abstract class AbstractResultSaver {
+public abstract class AbstractResultSaver implements IResultSaver {
 
     private static final String UNEXPECTED = "Unexpected";
 
@@ -57,6 +59,7 @@ public void saveFolder(String path) {
     public void copyFile(String source, String path, String entryName) {
     }
 
+    @Override
     public void saveClassFile(String path, String qualifiedName, String entryName, String content, int[] mapping) {
         if (mapping != null) {
             lineNumbers = true;

src/main/java/com/heliosdecompiler/transformerapi/common/FileLoader.java

@@ -34,13 +34,15 @@ public class FileLoader implements Loader {
 
     protected static final Pattern CLASS_SUFFIX_PATTERN = Pattern.compile("\\.class$");
 
+    private final Path rootDirectory;
+
     private final HashMap<String, byte[]> map = new HashMap<>();
 
     public FileLoader(String rootLocation, String pkg, String className) throws IOException {
         Objects.requireNonNull(rootLocation, "rootLocation");
         Objects.requireNonNull(className, "className");
 
-        Path rootDirectory = Paths.get(rootLocation);
+        this.rootDirectory = Paths.get(rootLocation);
         Validate.isTrue(Files.isDirectory(rootDirectory), "Not a directory: " + rootDirectory);
 
         String topLevelTypeName = stripClassSuffix(className);
@@ -95,11 +97,27 @@ protected String makeEntryName(String entryName) {
 
     @Override
     public byte[] load(String internalName) throws IOException {
-        return map.get(stripClassSuffix(internalName));
+        String key = stripClassSuffix(internalName);
+        byte[] data = map.get(key);
+        if (data != null) {
+            return data;
+        }
+        Path classFile = classFilePath(key);
+        if (!Files.isRegularFile(classFile)) {
+            return data;
+        }
+        data = Files.readAllBytes(classFile);
+        map.put(key, data);
+        return data;
     }
 
     @Override
     public boolean canLoad(String internalName) {
-        return map.containsKey(stripClassSuffix(internalName));
+        String key = stripClassSuffix(internalName);
+        return map.containsKey(key) || Files.isRegularFile(classFilePath(key));
+    }
+
+    protected Path classFilePath(String internalName) {
+        return rootDirectory.resolve(internalName + ".class");
     }
-}
+}

src/main/java/com/heliosdecompiler/transformerapi/common/Loader.java

@@ -117,7 +117,7 @@ public byte[] load(String internalName) throws IOException {
                 }
             }
         }
-        return null;
+        return classContents;
     }
 
     private static ZipFile openZipFile(String classpathEntry) throws IOException {

src/main/java/com/heliosdecompiler/transformerapi/common/ResultLinkSupport.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright 2026 Nicolas Baumann (@nbauma109)
+ *
+ * Licensed under the Apache License, Version 2.0.
+ */
+
+package com.heliosdecompiler.transformerapi.common;
+
+import java.util.Map;
+
+import jd.core.DecompilationResult;
+import jd.core.links.DeclarationData;
+import jd.core.links.HyperlinkReferenceData;
+import jd.core.links.ReferenceData;
+
+/**
+ * Shared helpers for writing declarations and hyperlinks into a {@link DecompilationResult}.
+ *
+ * @since 4.2.3
+ */
+public final class ResultLinkSupport {
+
+    /**
+     * Normalized symbol target used before writing JD-style link entries.
+     */
+    public record LinkTarget(String typeName, String name, String descriptor) {
+    }
+
+    private ResultLinkSupport() {
+    }
+
+    /**
+     * Register a declaration using the key format expected by JD-style consumers.
+     */
+    public static void addDeclaration(DecompilationResult result, int start, int length, LinkTarget target) {
+        DeclarationData data = new DeclarationData(start, length, target.typeName(), target.name(), target.descriptor());
+        result.addDeclaration(declarationKey(target), data);
+        if (target.name() == null) {
+            result.addTypeDeclaration(start, data);
+        }
+    }
+
+    /**
+     * Register a hyperlink backed by a cached reference object.
+     */
+    public static void addReference(DecompilationResult result, Map<String, ReferenceData> cache, int start, int length, LinkTarget target, String scopeInternalName) {
+        ReferenceData reference = reference(result, cache, target, scopeInternalName);
+        result.addHyperLink(start, new HyperlinkReferenceData(start, length, reference));
+    }
+
+    /**
+     * Resolve or create a reference so repeated mentions reuse the same instance.
+     */
+    public static ReferenceData reference(DecompilationResult result, Map<String, ReferenceData> cache, LinkTarget target, String scopeInternalName) {
+        // A stable cache key keeps the result model compact when the same target is referenced many times.
+        String key = declarationKey(target) + '-' + scopeInternalName;
+        return cache.computeIfAbsent(key, ignored -> {
+            ReferenceData reference = new ReferenceData(target.typeName(), target.name(), target.descriptor(), scopeInternalName);
+            reference.setEnabled(true);
+            result.addReference(reference);
+            return reference;
+        });
+    }
+
+    /**
+     * Build the declaration lookup key used by {@link DecompilationResult#getDeclarations()}.
+     */
+    public static String declarationKey(LinkTarget target) {
+        if (target.name() == null) {
+            return target.typeName();
+        }
+        return target.typeName() + '-' + target.name() + '-' + target.descriptor();
+    }
+
+    /**
+     * Measure the identifier length at a source offset.
+     */
+    public static int identifierLength(String code, int start) {
+        int end = start;
+        while (end < code.length() && Character.isJavaIdentifierPart(code.charAt(end))) {
+            end++;
+        }
+        return end - start;
+    }
+}

src/main/java/com/heliosdecompiler/transformerapi/decompilers/Decompiler.java

@@ -84,6 +84,9 @@ default ClassStruct readClassAndInnerClasses(Map<String, byte[]> importantData,
                     }
                 }
             }
+            if (classNode.superName != null && !"java/lang/Object".equals(classNode.superName) && loader.canLoad(classNode.superName)) {
+                importantData.putAll(readClassAndInnerClasses(importantData, loader, classNode.superName).importantData);
+            }
         }
         return new ClassStruct(fullClassName, importantData);
     }
@@ -114,15 +117,17 @@ public IOutputSink createOutputSink(IResultSaver saver) {
             return new IOutputSink() {
                 @Override
                 public void close() throws IOException {
+                    // not used
                 }
 
                 @Override
                 public void begin() {
+                    // not used
                 }
 
                 @Override
                 public void acceptOther(String path) {
-                 // not used
+                    // not used
                 }
 
                 @Override

src/main/java/com/heliosdecompiler/transformerapi/decompilers/cfr/CFRDataSource.java

@@ -40,6 +40,7 @@ public CFRDataSource(Loader loader, byte[] data, String name, Options options) {
 
     @Override
     public void informAnalysisRelativePathDetail(String usePath, String classFilePath) {
+        // not used
     }
 
     @Override

src/main/java/com/heliosdecompiler/transformerapi/decompilers/cfr/CFRDecompiler.java

@@ -1,4 +1,5 @@
 /*
+ * Copyright 2026 Nicolas Baumann (@nbauma109)
  * Copyright 2017 Sam Sun <github-contact@samczsun.com>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -21,6 +22,7 @@
 import org.benf.cfr.reader.util.CfrVersionInfo;
 import org.benf.cfr.reader.util.getopt.OptionsImpl;
 
+import com.heliosdecompiler.transformerapi.common.BytecodeSourceLinker;
 import com.heliosdecompiler.transformerapi.common.Loader;
 import com.heliosdecompiler.transformerapi.decompilers.Decompiler;
 
@@ -30,6 +32,9 @@
 import java.util.Scanner;
 import jd.core.DecompilationResult;
 
+/**
+ * Provides a gateway to the CFR decompiler.
+ */
 public class CFRDecompiler extends Decompiler.AbstractDecompiler implements Decompiler<CFRSettings> {
 
     public CFRDecompiler(String name) {
@@ -39,6 +44,7 @@ public CFRDecompiler(String name) {
     @Override
     public DecompilationResult decompile(Loader loader, String internalName, CFRSettings settings) throws IOException {
         StopWatch stopWatch = StopWatch.createStarted();
+        ClassStruct classStruct = readClassAndInnerClasses(loader, internalName);
         CFROutputStreamFactory sink = new CFROutputStreamFactory();
         String entryPath = internalName + ".class";
         OptionsImpl options = new OptionsImpl(settings.getSettings());
@@ -55,6 +61,8 @@ public DecompilationResult decompile(Loader loader, String internalName, CFRSett
         }
         DecompilationResult decompilationResult = new DecompilationResult();
         decompilationResult.setDecompiledOutput(resultCode);
+        // CFR emits text only, so link metadata is reconstructed from the source after decompilation.
+        BytecodeSourceLinker.link(decompilationResult, resultCode, classStruct.fullClassName(), classStruct.importantData());
         time = stopWatch.getTime();
         return decompilationResult;
     }

src/main/java/com/heliosdecompiler/transformerapi/decompilers/fernflower/FernflowerDecompiler.java

@@ -1,4 +1,5 @@
 /*
+ * Copyright 2026 Nicolas Baumann (@nbauma109)
  * Copyright 2017 Sam Sun <github-contact@samczsun.com>
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -23,6 +24,7 @@
 import org.jetbrains.java.decompiler.main.extern.IBytecodeProvider;
 import org.jetbrains.java.decompiler.struct.StructContext;
 
+import com.heliosdecompiler.transformerapi.common.BytecodeSourceLinker;
 import com.heliosdecompiler.transformerapi.common.Loader;
 import com.heliosdecompiler.transformerapi.decompilers.Decompiler;
 
@@ -33,7 +35,7 @@
 import jd.core.DecompilationResult;
 
 /**
- * Provides a gateway to the Fernflower decompiler
+ * Provides a gateway to the Fernflower decompiler.
  */
 public class FernflowerDecompiler extends Decompiler.AbstractDecompiler implements Decompiler<FernflowerSettings> {
 
@@ -63,7 +65,10 @@ public DecompilationResult decompile(Loader loader, String internalName, Fernflo
                 baseDecompiler.clearContext();
             }
             String key = classStruct.fullClassName();
-            decompilationResult.setDecompiledOutput(saver.getResults().get(key));
+            String source = saver.getResults().get(key);
+            decompilationResult.setDecompiledOutput(source);
+            // Fernflower does not expose token callbacks, so links are synthesized from source and bytecode.
+            BytecodeSourceLinker.link(decompilationResult, source, key, classStruct.importantData());
         }
         time = stopWatch.getTime();
         return decompilationResult;