Class Tweaker support

build.gradle

@@ -40,6 +40,7 @@ repositories {
 		url = 'https://maven.fabricmc.net/'
 	}
 	mavenCentral()
+	mavenLocal()
 }
 
 configurations {
@@ -81,6 +82,7 @@ dependencies {
 	// tinyfile management
 	implementation ('net.fabricmc:tiny-remapper:0.8.5')
 	implementation 'net.fabricmc:access-widener:2.1.0'
+	implementation 'net.fabricmc:class-tweaker:0.0.0'
 	implementation 'net.fabricmc:mapping-io:0.2.1'
 
 	implementation ('net.fabricmc:lorenz-tiny:4.0.2') {
@@ -113,6 +115,7 @@ dependencies {
 	}
 	testImplementation 'net.fabricmc:fabric-installer:0.9.0'
 	testImplementation 'org.mockito:mockito-core:4.8.0'
+	testImplementation 'com.google.jimfs:jimfs:1.2'
 
 	compileOnly 'org.jetbrains:annotations:23.0.0'
 	testCompileOnly 'org.jetbrains:annotations:23.0.0'

src/main/java/net/fabricmc/loom/configuration/classtweaker/ClassTweakerEntry.java

@@ -0,0 +1,75 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 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.configuration.classtweaker;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.jetbrains.annotations.VisibleForTesting;
+
+import net.fabricmc.classtweaker.api.ClassTweaker;
+import net.fabricmc.classtweaker.api.visitor.ClassTweakerVisitor;
+import net.fabricmc.loom.util.fmj.FabricModJson;
+import net.fabricmc.loom.util.fmj.ModEnvironment;
+
+public record ClassTweakerEntry(FabricModJson modJson, String path, ModEnvironment environment, boolean local) {
+	public static List<ClassTweakerEntry> readAll(FabricModJson modJson, boolean local) {
+		var entries = new ArrayList<ClassTweakerEntry>();
+
+		for (Map.Entry<String, ModEnvironment> entry : modJson.getClassTweakers().entrySet()) {
+			entries.add(new ClassTweakerEntry(modJson, entry.getKey(), entry.getValue(), local));
+		}
+
+		return Collections.unmodifiableList(entries);
+	}
+
+	@VisibleForTesting
+	public int maxSupportedVersion() {
+		if (modJson.getMetadataVersion() >= 2) {
+			// FMJ 2.0 is required for class tweaker support. Otherwise limited to access wideners.
+			return ClassTweaker.CT_V1;
+		}
+
+		return ClassTweaker.AW_V2;
+	}
+
+	public void read(ClassTweakerFactory factory, ClassTweakerVisitor classTweakerVisitor) throws IOException {
+		final byte[] data = readRaw();
+		final int ctVersion = factory.readVersion(data);
+
+		if (ctVersion > maxSupportedVersion()) {
+			throw new UnsupportedOperationException("Class tweaker '%s' with version '%d' from mod '%s' is not supported with by this metadata version '%d'.".formatted(path, ctVersion, modJson.getId(), modJson().getMetadataVersion()));
+		}
+
+		factory.read(classTweakerVisitor, data, modJson.getId());
+	}
+
+	private byte[] readRaw() throws IOException {
+		return modJson.getSource().read(path);
+	}
+}

src/main/java/net/fabricmc/loom/configuration/classtweaker/ClassTweakerFactory.java

@@ -0,0 +1,44 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 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.configuration.classtweaker;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.List;
+
+import net.fabricmc.classtweaker.api.ClassTweaker;
+import net.fabricmc.classtweaker.api.visitor.ClassTweakerVisitor;
+
+public interface ClassTweakerFactory {
+	ClassTweakerFactory DEFAULT = new ClassTweakerFactoryImpl();
+
+	int readVersion(byte[] data);
+
+	void read(ClassTweakerVisitor visitor, byte[] data, String modId);
+
+	ClassTweaker readEntries(List<ClassTweakerEntry> entries) throws IOException;
+
+	void transformJar(Path jar, ClassTweaker classTweaker) throws IOException;
+}

src/main/java/net/fabricmc/loom/configuration/classtweaker/ClassTweakerFactoryImpl.java

@@ -0,0 +1,73 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 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.configuration.classtweaker;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Objects;
+
+import net.fabricmc.classtweaker.api.ClassTweaker;
+import net.fabricmc.classtweaker.api.ClassTweakerReader;
+import net.fabricmc.classtweaker.api.visitor.ClassTweakerVisitor;
+
+final class ClassTweakerFactoryImpl implements ClassTweakerFactory {
+	@Override
+	public int readVersion(byte[] data) {
+		Objects.requireNonNull(data);
+		return ClassTweakerReader.readVersion(data);
+	}
+
+	@Override
+	public void read(ClassTweakerVisitor visitor, byte[] data, String modId) {
+		Objects.requireNonNull(visitor);
+		Objects.requireNonNull(data);
+		Objects.requireNonNull(modId);
+
+		ClassTweakerReader.create(visitor).read(data, modId);
+	}
+
+	@Override
+	public ClassTweaker readEntries(List<ClassTweakerEntry> entries) throws IOException {
+		final ClassTweaker classTweaker = ClassTweaker.newInstance();
+
+		for (ClassTweakerEntry entry : entries) {
+			ClassTweakerVisitor visitor = classTweaker;
+
+			if (!entry.local()) {
+				visitor = ClassTweakerVisitor.transitiveOnly(visitor);
+			}
+
+			entry.read(this, visitor);
+		}
+
+		return classTweaker;
+	}
+
+	@Override
+	public void transformJar(Path jar, ClassTweaker classTweaker) throws IOException {
+		new ClassTweakerJarTransformer(classTweaker).transform(jar);
+	}
+}

src/main/java/net/fabricmc/loom/configuration/classtweaker/ClassTweakerJarProcessor.java

@@ -0,0 +1,103 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 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.configuration.classtweaker;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.jetbrains.annotations.Nullable;
+
+import net.fabricmc.classtweaker.api.ClassTweaker;
+import net.fabricmc.loom.api.processor.MinecraftJarProcessor;
+import net.fabricmc.loom.api.processor.ProcessorContext;
+import net.fabricmc.loom.api.processor.SpecContext;
+import net.fabricmc.loom.util.fmj.FabricModJson;
+import net.fabricmc.loom.util.fmj.ModEnvironment;
+
+public abstract class ClassTweakerJarProcessor implements MinecraftJarProcessor<ClassTweakerJarProcessor.Spec> {
+	private final ClassTweakerFactory classTweakerFactory;
+
+	public ClassTweakerJarProcessor(ClassTweakerFactory classTweakerFactory) {
+		this.classTweakerFactory = classTweakerFactory;
+	}
+
+	@Override
+	public @Nullable ClassTweakerJarProcessor.Spec buildSpec(SpecContext context) {
+		var classTweakers = new ArrayList<ClassTweakerEntry>();
+
+		for (FabricModJson localMod : context.localMods()) {
+			classTweakers.addAll(ClassTweakerEntry.readAll(localMod, true));
+		}
+
+		for (FabricModJson dependentMod : context.modDependencies()) {
+			// TODO check and cache if it has any transitive CTs
+			classTweakers.addAll(ClassTweakerEntry.readAll(dependentMod, false));
+		}
+
+		if (classTweakers.isEmpty()) {
+			return null;
+		}
+
+		return new Spec(Collections.unmodifiableList(classTweakers));
+	}
+
+	public record Spec(List<ClassTweakerEntry> classTweakers) implements MinecraftJarProcessor.Spec {
+		List<ClassTweakerEntry> getSupportedClassTweakers(ProcessorContext context) {
+			return classTweakers.stream()
+					.filter(entry -> isSupported(entry.environment(), context))
+					.toList();
+		}
+
+		private static boolean isSupported(ModEnvironment modEnvironment, ProcessorContext context) {
+			if (context.isMerged()) {
+				// All envs are supported wth a merged jar
+				return true;
+			}
+
+			if (context.includesClient() && modEnvironment.isClient()) {
+				return true;
+			}
+
+			if (context.includesServer() && modEnvironment.isServer()) {
+				return true;
+			}
+
+			// Universal supports all jars
+			return modEnvironment == ModEnvironment.UNIVERSAL;
+		}
+	}
+
+	@Override
+	public void processJar(Path jar, Spec spec, ProcessorContext context) throws IOException {
+		assert !spec.classTweakers.isEmpty();
+
+		final List<ClassTweakerEntry> classTweakers = spec.getSupportedClassTweakers(context);
+		final ClassTweaker classTweaker = classTweakerFactory.readEntries(classTweakers);
+		classTweakerFactory.transformJar(jar, classTweaker);
+	}
+}