1 files changed, 148 insertions, 0 deletions
diff --git a/src/main/java/net/fabricmc/loom/decompilers/cfr/LoomCFRDecompiler.java b/src/main/java/net/fabricmc/loom/decompilers/cfr/LoomCFRDecompiler.java
new file mode 100644
index 00000000..bbfb0be2
--- /dev/null
+++ b/src/main/java/net/fabricmc/loom/decompilers/cfr/LoomCFRDecompiler.java
@@ -0,0 +1,148 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2021 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.decompilers.cfr;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.io.Writer;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Collections;
+import java.util.Map;
+import java.util.jar.Attributes;
+import java.util.jar.JarOutputStream;
+import java.util.jar.Manifest;
+
+import org.benf.cfr.reader.Driver;
+import org.benf.cfr.reader.state.ClassFileSourceImpl;
+import org.benf.cfr.reader.state.DCCommonState;
+import org.benf.cfr.reader.util.AnalysisType;
+import org.benf.cfr.reader.util.getopt.Options;
+import org.benf.cfr.reader.util.getopt.OptionsImpl;
+import org.benf.cfr.reader.util.output.SinkDumperFactory;
+
+import net.fabricmc.loom.api.decompilers.DecompilationMetadata;
+import net.fabricmc.loom.api.decompilers.LoomDecompiler;
+import net.fabricmc.loom.decompilers.LineNumberRemapper;
+
+public class LoomCFRDecompiler implements LoomDecompiler {
+	private static final Map<String, String> DECOMPILE_OPTIONS = Map.of(
+			"renameillegalidents", "true",
+			"trackbytecodeloc", "true",
+			"comments", "false"
+	);
+
+	@Override
+	public String name() {
+		return "Cfr";
+	}
+
+	@Override
+	public void decompile(Path compiledJar, Path sourcesDestination, Path linemapDestination, DecompilationMetadata metaData) {
+		final String path = compiledJar.toAbsolutePath().toString();
+		final Options options = OptionsImpl.getFactory().create(DECOMPILE_OPTIONS);
+
+		ClassFileSourceImpl classFileSource = new ClassFileSourceImpl(options);
+
+		for (Path library : metaData.libraries()) {
+			classFileSource.addJarContent(library.toAbsolutePath().toString(), AnalysisType.JAR);
+		}
+
+		classFileSource.informAnalysisRelativePathDetail(null, null);
+
+		DCCommonState state = new DCCommonState(options, classFileSource);
+
+		if (metaData.javaDocs() != null) {
+			state = new DCCommonState(state, new CFRObfuscationMapping(metaData.javaDocs()));
+		}
+
+		final Manifest manifest = new Manifest();
+		manifest.getMainAttributes().put(Attributes.Name.MANIFEST_VERSION, "1.0");
+
+		Map<String, Map<Integer, Integer>> lineMap;
+
+		try (JarOutputStream outputStream = new JarOutputStream(Files.newOutputStream(sourcesDestination), manifest)) {
+			CFRSinkFactory cfrSinkFactory = new CFRSinkFactory(outputStream, metaData.logger());
+			SinkDumperFactory dumperFactory = new SinkDumperFactory(cfrSinkFactory, options);
+
+			Driver.doJar(state, path, AnalysisType.JAR, dumperFactory);
+
+			lineMap = cfrSinkFactory.getLineMap();
+		} catch (IOException e) {
+			throw new UncheckedIOException("Failed to decompile", e);
+		}
+
+		writeLineMap(linemapDestination, lineMap);
+	}
+
+	private void writeLineMap(Path output, Map<String, Map<Integer, Integer>> lineMap) {
+		try (Writer writer = Files.newBufferedWriter(output, StandardCharsets.UTF_8)) {
+			for (Map.Entry<String, Map<Integer, Integer>> classEntry : lineMap.entrySet()) {
+				final String name = classEntry.getKey().replace(".", "/");
+
+				final Map<Integer, Integer> mapping = classEntry.getValue();
+
+				int maxLine = 0;
+				int maxLineDest = 0;
+				StringBuilder builder = new StringBuilder();
+
+				for (Map.Entry<Integer, Integer> mappingEntry : mapping.entrySet()) {
+					final int src = mappingEntry.getKey();
+					final int dst = mappingEntry.getValue();
+
+					maxLine = Math.max(maxLine, src);
+					maxLineDest = Math.max(maxLineDest, dst);
+
+					builder.append("\t").append(src).append("\t").append(dst).append("\n");
+				}
+
+				writer.write("%s\t%d\t%d\n".formatted(name, maxLine, maxLineDest));
+				writer.write(builder.toString());
+				writer.write("\n");
+			}
+		} catch (IOException e) {
+			throw new UncheckedIOException("Failed to write line map", e);
+		}
+	}
+
+	// A test main class to make it quicker/easier to debug with minimal jars
+	public static void main(String[] args) throws IOException {
+		LoomCFRDecompiler decompiler = new LoomCFRDecompiler();
+
+		Path lineMap = Paths.get("linemap.txt");
+
+		decompiler.decompile(Paths.get("input.jar"),
+				Paths.get("output-sources.jar"),
+				lineMap,
+				new DecompilationMetadata(4, null, Collections.emptyList(), null)
+		);
+
+		LineNumberRemapper lineNumberRemapper = new LineNumberRemapper();
+		lineNumberRemapper.readMappings(lineMap.toFile());
+		lineNumberRemapper.process(null, Paths.get("input.jar"), Paths.get("output.jar"));
+	}
+}