feat: improve API ergonomics, arbitrary class file sources

README.md

@@ -10,7 +10,12 @@ const { decompile } = require("./cfr.js"); // get it from the dist/ directory or
 
 const data = fs.readFileSync("./your/package/HelloWorld.class"); // read a class file
 console.log(decompile(data, {
-    classes: [] /* no additional classes for analysis */,
+    source: (name) => {
+        /* provide any additional classes for analysis here */
+
+        console.log(name); /* internal name, e.g. java/lang/Object */
+        return null; /* class not available */
+    },
     options: {
         /* see https://github.com/leibnitz27/cfr/blob/master/src/org/benf/cfr/reader/util/getopt/OptionsImpl.java#L274 */
         "hidelangimports": "false", /* testing option - don't hide java.lang imports */

docs/index.html

@@ -81,7 +81,7 @@
                     console.log(`Decompiling ${name}...`);
 
                     document.getElementById("file-content").textContent = // stripHeader(
-                        decompile(new Int8Array(evt.target.result), { classes: [], options: {} });
+                        decompile(new Int8Array(evt.target.result));
                     // );
 
                     console.log(`Decompiled ${name} in ${Date.now() - start}ms.`);

src/main/java/dev/cephx/cfr/DecompilerOptions.java

@@ -2,22 +2,28 @@
 
 import org.teavm.jso.JSBody;
 import org.teavm.jso.JSByRef;
+import org.teavm.jso.JSFunctor;
 import org.teavm.jso.JSObject;
-import org.teavm.jso.JSProperty;
 
 public interface DecompilerOptions extends JSObject {
-    @JSProperty
-    @JSByRef
-    byte[][] getClasses();
-
-    @JSBody(script = "return Object.entries(this.options).map(e => { return { name: e[0], value: e[1] }; });")
+    @JSBody(script = "return this.options ? Object.entries(this.options) : [];")
     Option[] getOptions();
 
+    // can't use the logical OR, it breaks the TeaVM minifier
+    @JSBody(script = "return this.source ? this.source : (() => { return null; });")
+    Source getSource();
+
     interface Option extends JSObject {
-        @JSProperty
+        @JSBody(script = "return this[0];")
         String getName();
 
-        @JSProperty
+        @JSBody(script = "return this[1];")
         String getValue();
     }
+
+    @JSFunctor
+    interface Source extends JSObject {
+        @JSByRef
+        byte[] get(String name);
+    }
 }

src/main/java/dev/cephx/cfr/Main.java

@@ -2,26 +2,32 @@
 
 import dev.cephx.cfr.source.ByteArrayClassSource;
 import dev.cephx.cfr.source.CompositeClassSource;
-import dev.cephx.cfr.source.OutputSinkFactoryImpl;
+import dev.cephx.cfr.sink.OutputSinkFactoryImpl;
+import dev.cephx.cfr.source.SimpleClassSource;
 import dev.cephx.cfr.source.VMClassSource;
 import org.benf.cfr.reader.api.CfrDriver;
 import org.teavm.jso.JSByRef;
 import org.teavm.jso.JSExport;
+import org.teavm.jso.core.JSObjects;
 
 import java.util.Arrays;
+import java.util.List;
 import java.util.stream.Collectors;
 
 public class Main {
     @JSExport
     public static String decompile(@JSByRef byte[] b, DecompilerOptions options) throws Throwable {
-        final OutputSinkFactoryImpl sinkFactory = new OutputSinkFactoryImpl();
+        if (options == null || JSObjects.isUndefined(options)) {
+            options = JSObjects.create();
+        }
 
+        final var sinkFactory = new OutputSinkFactoryImpl();
         final var source = new ByteArrayClassSource(b);
         new CfrDriver.Builder()
                 .withClassFileSource(
                         new CompositeClassSource(
                                 source,
-                                new ByteArrayClassSource(options.getClasses()),
+                                new SimpleClassSource(options.getSource()::get),
                                 VMClassSource.INSTANCE
                         )
                 )
@@ -34,7 +40,7 @@ public static String decompile(@JSByRef byte[] b, DecompilerOptions options) thr
                                 ))
                 )
                 .build()
-                .analyse(source.names());
+                .analyse(List.of(source.name()));
 
         return sinkFactory.outputOrThrow();
     }

src/main/java/dev/cephx/cfr/source/OutputSinkFactoryImpl.java → src/main/java/dev/cephx/cfr/sink/OutputSinkFactoryImpl.java

@@ -1,4 +1,4 @@
-package dev.cephx.cfr.source;
+package dev.cephx.cfr.sink;
 
 import org.benf.cfr.reader.api.OutputSinkFactory;
 

src/main/java/dev/cephx/cfr/source/ByteArrayClassSource.java

@@ -3,19 +3,12 @@
 import org.benf.cfr.reader.api.ClassFileSource;
 import org.benf.cfr.reader.bytecode.analysis.parse.utils.Pair;
 
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
-import java.util.Map;
-import java.util.stream.Collectors;
-
-public record ByteArrayClassSource(Map<String, byte[]> classes) implements ClassFileSource {
-    public ByteArrayClassSource(byte[]... classes) {
-        this(
-                Arrays.stream(classes)
-                        .map(b -> Map.entry(ClassFileUtil.getClassName(b), b))
-                        .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))
-        );
+
+public record ByteArrayClassSource(String name, byte[] data) implements ClassFileSource {
+    public ByteArrayClassSource(byte[] data) {
+        this(ClassFileUtil.getClassName(data), data);
     }
 
     @Override
@@ -41,11 +34,6 @@ public Pair<byte[], String> getClassFileContent(String path) {
             name = path.substring(0, extIndex);
         }
 
-        final byte[] data = classes.get(name);
-        return data != null ? new Pair<>(data, path) : null;
-    }
-
-    public List<String> names() {
-        return List.copyOf(classes.keySet());
+        return this.name.equals(name) ? new Pair<>(this.data, path) : null;
     }
 }

src/main/java/dev/cephx/cfr/source/SimpleClassSource.java

@@ -0,0 +1,37 @@
+package dev.cephx.cfr.source;
+
+import org.benf.cfr.reader.api.ClassFileSource;
+import org.benf.cfr.reader.bytecode.analysis.parse.utils.Pair;
+
+import java.util.Collection;
+import java.util.List;
+import java.util.function.Function;
+
+public record SimpleClassSource(Function<String, byte[]> source) implements ClassFileSource {
+    @Override
+    public void informAnalysisRelativePathDetail(String usePath, String classFilePath) {
+    }
+
+    @Override
+    public Collection<String> addJar(String jarPath) {
+        return List.of();
+    }
+
+    @Override
+    public String getPossiblyRenamedPath(String path) {
+        return path;
+    }
+
+    @Override
+    public Pair<byte[], String> getClassFileContent(String path) {
+        String name = path;
+
+        final int extIndex = path.indexOf(".class");
+        if (extIndex != -1) {
+            name = path.substring(0, extIndex);
+        }
+
+        final byte[] b = this.source.apply(name);
+        return b != null ? new Pair<>(b, path) : null;
+    }
+}