Allow adding additional jar processors (#247)

* processors

* cleanup

* oops

* make changes

* blargh

src/main/java/net/fabricmc/loom/LoomGradleExtension.java

@@ -47,6 +47,7 @@ import org.gradle.api.file.ConfigurableFileCollection;
 import org.gradle.api.plugins.BasePluginConvention;
 
 import net.fabricmc.loom.api.decompilers.LoomDecompiler;
+import net.fabricmc.loom.processors.JarProcessor;
 import net.fabricmc.loom.processors.JarProcessorManager;
 import net.fabricmc.loom.providers.MappingsProvider;
 import net.fabricmc.loom.providers.MinecraftMappedProvider;
@@ -67,6 +68,7 @@ public class LoomGradleExtension {
 	private final ConfigurableFileCollection unmappedMods;
 
 	final List<LoomDecompiler> decompilers = new ArrayList<>();
+	private final List<JarProcessor> jarProcessors = new ArrayList<>();
 
 	// Not to be set in the build.gradle
 	private final Project project;
@@ -84,6 +86,17 @@ public class LoomGradleExtension {
 		decompilers.add(decompiler);
 	}
 
+	/**
+	 * Add a transformation over the mapped mc jar.
+	 * Adding any jar processor will cause mapped mc jars to be stored per-project so that
+	 * different transformation can be applied in different projects.
+	 * This means remapping will need to be done individually per-project, which is slower when developing
+	 * more than one project using the same minecraft version.
+	 */
+	public void addJarProcessor(JarProcessor processor) {
+		jarProcessors.add(processor);
+	}
+
 	public MappingSet getOrCreateSrcMappingCache(int id, Supplier<MappingSet> factory) {
 		return srcMappingCache[id] != null ? srcMappingCache[id] : (srcMappingCache[id] = factory.get());
 	}
@@ -338,6 +351,10 @@ public class LoomGradleExtension {
 		this.jarProcessorManager = jarProcessorManager;
 	}
 
+	public List<JarProcessor> getJarProcessors() {
+		return jarProcessors;
+	}
+
 	public String getRefmapName() {
 		if (refmapName == null || refmapName.isEmpty()) {
 			String defaultRefmapName = project.getConvention().getPlugin(BasePluginConvention.class).getArchivesBaseName() + "-refmap.json";

src/main/java/net/fabricmc/loom/processors/JarProcessor.java

@@ -26,12 +26,16 @@ package net.fabricmc.loom.processors;
 
 import java.io.File;
 
-import org.gradle.api.Project;
-
 public interface JarProcessor {
-	void setup(Project project);
+	void setup();
 
+	/**
+	 * Currently this is a destructive process that replaces the existing jar.
+	 */
 	void process(File file);
 
+	/**
+	 * Return true to make all jar processors run again, return false to use the existing results of jar processing.
+	 */
 	boolean isInvalid(File file);
 }

src/main/java/net/fabricmc/loom/processors/JarProcessorManager.java

@@ -25,37 +25,17 @@
 package net.fabricmc.loom.processors;
 
 import java.io.File;
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
-import org.gradle.api.Project;
-
-import net.fabricmc.loom.util.accesswidener.AccessWidenerJarProcessor;
-import net.fabricmc.loom.LoomGradleExtension;
-
 public class JarProcessorManager {
-	private final Project project;
-	private final LoomGradleExtension extension;
-
 	private final List<JarProcessor> jarProcessors;
 
-	public JarProcessorManager(Project project) {
-		this.project = project;
-		this.extension = project.getExtensions().getByType(LoomGradleExtension.class);
-		jarProcessors = setupProcessors();
+	public JarProcessorManager(List<JarProcessor> jarProcessors) {
+		this.jarProcessors = jarProcessors;
 	}
 
-	//TODO possibly expand via an API?
-	private List<JarProcessor> setupProcessors() {
-		List<JarProcessor> jarProcessors = new ArrayList<>();
-
-		if (extension.accessWidener != null) {
-			jarProcessors.add(new AccessWidenerJarProcessor());
-		}
-
-		jarProcessors.forEach(jarProcessor -> jarProcessor.setup(project));
-		return Collections.unmodifiableList(jarProcessors);
+	public void setupProcessors() {
+		jarProcessors.forEach(JarProcessor::setup);
 	}
 
 	public boolean active() {

src/main/java/net/fabricmc/loom/providers/MappingsProvider.java

@@ -44,18 +44,20 @@ import org.zeroturnaround.zip.FileSource;
 import org.zeroturnaround.zip.ZipEntrySource;
 import org.zeroturnaround.zip.ZipUtil;
 
+import net.fabricmc.loom.LoomGradleExtension;
+import net.fabricmc.loom.processors.JarProcessorManager;
+import net.fabricmc.loom.processors.MinecraftProcessedProvider;
 import net.fabricmc.loom.util.Constants;
+import net.fabricmc.loom.util.DeletingFileVisitor;
 import net.fabricmc.loom.util.DependencyProvider;
 import net.fabricmc.loom.util.DownloadUtil;
+import net.fabricmc.loom.util.accesswidener.AccessWidenerJarProcessor;
 import net.fabricmc.mapping.reader.v2.TinyV2Factory;
 import net.fabricmc.mapping.tree.TinyTree;
 import net.fabricmc.stitch.Command;
 import net.fabricmc.stitch.commands.CommandProposeFieldNames;
 import net.fabricmc.stitch.commands.tinyv2.CommandMergeTinyV2;
 import net.fabricmc.stitch.commands.tinyv2.CommandReorderTinyV2;
-import net.fabricmc.loom.processors.JarProcessorManager;
-import net.fabricmc.loom.processors.MinecraftProcessedProvider;
-import net.fabricmc.loom.util.DeletingFileVisitor;
 
 public class MappingsProvider extends DependencyProvider {
 	public MinecraftMappedProvider mappedProvider;
@@ -140,8 +142,15 @@ public class MappingsProvider extends DependencyProvider {
 
 		addDependency(tinyMappingsJar, Constants.MAPPINGS_FINAL);
 
-		JarProcessorManager processorManager = new JarProcessorManager(getProject());
-		getExtension().setJarProcessorManager(processorManager);
+		LoomGradleExtension extension = getExtension();
+
+		if (extension.accessWidener != null) {
+			extension.addJarProcessor(new AccessWidenerJarProcessor(getProject()));
+		}
+
+		JarProcessorManager processorManager = new JarProcessorManager(extension.getJarProcessors());
+		extension.setJarProcessorManager(processorManager);
+		processorManager.setupProcessors();
 
 		if (processorManager.active()) {
 			mappedProvider = new MinecraftProcessedProvider(getProject(), processorManager);

src/main/java/net/fabricmc/loom/util/accesswidener/AccessWidenerJarProcessor.java

@@ -50,20 +50,23 @@ import org.zeroturnaround.zip.transform.ByteArrayZipEntryTransformer;
 import org.zeroturnaround.zip.transform.ZipEntryTransformer;
 import org.zeroturnaround.zip.transform.ZipEntryTransformerEntry;
 
-import net.fabricmc.mappings.EntryTriple;
 import net.fabricmc.loom.LoomGradleExtension;
-import net.fabricmc.loom.util.Checksum;
 import net.fabricmc.loom.processors.JarProcessor;
+import net.fabricmc.loom.util.Checksum;
+import net.fabricmc.mappings.EntryTriple;
 import net.fabricmc.tinyremapper.TinyRemapper;
 
 public class AccessWidenerJarProcessor implements JarProcessor {
 	private AccessWidener accessWidener = new AccessWidener();
-	private Project project;
+	private final Project project;
 	private byte[] inputHash;
 
-	@Override
-	public void setup(Project project) {
+	public AccessWidenerJarProcessor(Project project) {
 		this.project = project;
+	}
+
+	@Override
+	public void setup() {
 		LoomGradleExtension loomGradleExtension = project.getExtensions().getByType(LoomGradleExtension.class);
 
 		if (!loomGradleExtension.accessWidener.exists()) {