Add Java-based core mods

Mods must ship a separate Jar-file (for example via jar-in-jar) and mark it as FMLModType: LIBRARY to make it load above the GAME layer. They then must provide an implementation of ICoreMod via the Java ServiceLoader to contribute their transformers.
neoforged · Apr 5, 2024 · 6a410b4 · 6a410b4
1 parent df388c3
commit 6a410b4
Show file tree

Hide file tree

Showing 5 changed files with 79 additions and 19 deletions.
diff --git a/loader/src/main/java/net/neoforged/fml/loading/FMLLoader.java b/loader/src/main/java/net/neoforged/fml/loading/FMLLoader.java
@@ -23,7 +23,6 @@
 import net.neoforged.accesstransformer.api.AccessTransformerEngine;
 import net.neoforged.accesstransformer.ml.AccessTransformerService;
 import net.neoforged.api.distmarker.Dist;
-import net.neoforged.coremod.CoreModScriptingEngine;
 import net.neoforged.fml.common.asm.RuntimeDistCleaner;
 import net.neoforged.fml.loading.mixin.DeferredMixinConfigRegistration;
 import net.neoforged.fml.loading.moddiscovery.BackgroundScanHandler;
@@ -38,7 +37,6 @@ public class FMLLoader {
     private static final Logger LOGGER = LogUtils.getLogger();
     private static AccessTransformerEngine accessTransformer;
     private static ModDiscoverer modDiscoverer;
-    private static CoreModScriptingEngine coreModEngine;
     private static LanguageLoadingProvider languageLoadingProvider;
     private static Dist dist;
     private static LoadingModList loadingModList;
@@ -89,9 +87,6 @@ static void onInitialLoad(IEnvironment environment, Set<String> otherServices) t
         });
         LOGGER.debug(LogMarkers.CORE, "Found Runtime Dist Cleaner");
 
-        coreModEngine = new CoreModScriptingEngine();
-        LOGGER.debug(LogMarkers.CORE, "FML found CoreMods version : {}", coreModEngine.getClass().getPackage().getImplementationVersion());
-
         LOGGER.debug(LogMarkers.CORE, "Found ForgeSPI package implementation version {}", Environment.class.getPackage().getImplementationVersion());
         LOGGER.debug(LogMarkers.CORE, "Found ForgeSPI package specification {}", Environment.class.getPackage().getSpecificationVersion());
         if (Integer.parseInt(Environment.class.getPackage().getSpecificationVersion()) < 2) {
@@ -156,10 +151,6 @@ public static List<ITransformationService.Resource> completeScan(IModuleLayerMan
         return List.of(modValidator.getModResources());
     }
 
-    static CoreModScriptingEngine getCoreModEngine() {
-        return coreModEngine;
-    }
-
     public static LanguageLoadingProvider getLanguageLoadingProvider() {
         return languageLoadingProvider;
     }

diff --git a/loader/src/main/java/net/neoforged/fml/loading/FMLServiceProvider.java b/loader/src/main/java/net/neoforged/fml/loading/FMLServiceProvider.java
@@ -8,22 +8,28 @@
 import static net.neoforged.fml.loading.LogMarkers.CORE;
 
 import com.mojang.logging.LogUtils;
+import cpw.mods.modlauncher.Launcher;
 import cpw.mods.modlauncher.api.IEnvironment;
 import cpw.mods.modlauncher.api.IModuleLayerManager;
 import cpw.mods.modlauncher.api.ITransformationService;
 import cpw.mods.modlauncher.api.ITransformer;
 import cpw.mods.modlauncher.api.IncompatibleEnvironmentException;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.ServiceLoader;
 import java.util.Set;
 import java.util.function.BiFunction;
 import joptsimple.ArgumentAcceptingOptionSpec;
 import joptsimple.OptionSpecBuilder;
+import net.neoforged.coremod.CoreModScriptingEngine;
 import net.neoforged.fml.loading.moddiscovery.ModFile;
 import net.neoforged.neoforgespi.Environment;
+import net.neoforged.neoforgespi.coremod.ICoreMod;
 import org.slf4j.Logger;
 
 public class FMLServiceProvider implements ITransformationService {
@@ -129,6 +135,63 @@ public void argumentValues(OptionResult option) {
     @Override
     public List<? extends ITransformer<?>> transformers() {
         LOGGER.debug(CORE, "Loading coremod transformers");
-        return FMLLoader.getCoreModEngine().initializeCoreMods();
+
+        var result = new ArrayList<ITransformer<?>>();
+        addCoreModScripts(result);
+
+        // Find all Java core mods
+        var pluginLayer = Launcher.INSTANCE.findLayerManager()
+                .flatMap(m -> m.getLayer(IModuleLayerManager.Layer.PLUGIN))
+                .orElseThrow();
+        for (var coreMod : ServiceLoader.load(pluginLayer, ICoreMod.class)) {
+            for (var transformer : coreMod.getTransformers()) {
+                if (transformer == null) {
+                    throw new IllegalStateException("Core mod " + coreMod + " is trying to add null transformer");
+                }
+                LOGGER.debug(CORE, "Adding {} transformer from core-mod {}", transformer.targets(), coreMod);
+                result.add(transformer);
+            }
+        }
+
+        return result;
+    }
+
+    /**
+     * Enumerate script-based coremods.
+     */
+    private void addCoreModScripts(List<ITransformer<?>> transformers) {
+        var modFiles = LoadingModList.get().getModFiles();
+
+        var modsThatNeedCoreModScripting = new HashSet<>();
+        for (var modFile : modFiles) {
+            if (!modFile.getFile().getCoreMods().isEmpty()) {
+                modsThatNeedCoreModScripting.add(modFile.getFile().getFileName());
+            }
+        }
+
+        if (modsThatNeedCoreModScripting.isEmpty()) {
+            // Don't even bother starting the scripting engine if no mod contains scripting core mods
+            LOGGER.debug(LogMarkers.CORE, "Not loading coremod script-engine since no mod requested it");
+            return;
+        }
+
+        LOGGER.info(LogMarkers.CORE, "Loading coremod script-engine for {}", modsThatNeedCoreModScripting);
+
+        CoreModScriptingEngine engine;
+        try {
+            engine = new CoreModScriptingEngine();
+        } catch (NoClassDefFoundError e) {
+            // Fail for all mods that require a coremod scripting engine to be present
+            throw new IllegalStateException("Could not find the coremod script-engine, but the following mods require it: " + modsThatNeedCoreModScripting, e);
+        }
+
+        LOGGER.debug(LogMarkers.CORE, "Loading coremod scripts");
+        for (var modFile : modFiles) {
+            for (var coreMod : modFile.getFile().getCoreMods()) {
+                engine.loadCoreMod(coreMod);
+            }
+        }
+
+        transformers.addAll(engine.initializeCoreMods());
     }
 }
diff --git a/loader/src/main/java/net/neoforged/fml/loading/LoadingModList.java b/loader/src/main/java/net/neoforged/fml/loading/LoadingModList.java
@@ -66,14 +66,6 @@ public static LoadingModList get() {
         return INSTANCE;
     }
 
-    public void addCoreMods() {
-        modFiles.stream()
-                .map(ModFileInfo::getFile)
-                .map(ModFile::getCoreMods)
-                .flatMap(List::stream)
-                .forEach(FMLLoader.getCoreModEngine()::loadCoreMod);
-    }
-
     public void addMixinConfigs() {
         modFiles.stream()
                 .map(ModFileInfo::getFile)

diff --git a/loader/src/main/java/net/neoforged/fml/loading/moddiscovery/ModValidator.java b/loader/src/main/java/net/neoforged/fml/loading/moddiscovery/ModValidator.java
@@ -101,7 +101,6 @@ public BackgroundScanHandler stage2Validation() {
         allErrors.addAll(this.discoveryErrorData);
 
         loadingModList = ModSorter.sort(candidateMods, allErrors);
-        loadingModList.addCoreMods();
         loadingModList.addAccessTransformers();
         loadingModList.addMixinConfigs();
         loadingModList.setBrokenFiles(brokenFiles);

diff --git a/spi/src/main/java/net/neoforged/neoforgespi/coremod/ICoreMod.java b/spi/src/main/java/net/neoforged/neoforgespi/coremod/ICoreMod.java
@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) NeoForged and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.neoforged.neoforgespi.coremod;
+
+import cpw.mods.modlauncher.api.ITransformer;
+
+/**
+ * Provide using the Java {@link java.util.ServiceLoader} mechanism.
+ */
+public interface ICoreMod {
+    Iterable<? extends ITransformer<?>> getTransformers();
+}