Add overlap handling to GamePatch.process. Helps with #376

minecraft/src/main/java/org/quiltmc/loader/impl/game/minecraft/patch/BrandingPatch.java

@@ -15,33 +15,31 @@
  * limitations under the License.
  */
 
-import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.tree.AbstractInsnNode;
 import org.objectweb.asm.tree.ClassNode;
 import org.objectweb.asm.tree.MethodInsnNode;
 import org.objectweb.asm.tree.MethodNode;
 import org.quiltmc.loader.impl.entrypoint.GamePatch;
+import org.quiltmc.loader.impl.entrypoint.GamePatchContext;
 import org.quiltmc.loader.impl.launch.common.QuiltLauncher;
 import org.quiltmc.loader.impl.util.log.Log;
 import org.quiltmc.loader.impl.util.log.LogCategory;
 
 import java.util.ListIterator;
-import java.util.function.Consumer;
-import java.util.function.Function;
 
 public final class BrandingPatch extends GamePatch {
 	@Override
-	public void process(QuiltLauncher launcher, Function<String, ClassReader> classSource, Consumer<ClassNode> classEmitter) {
+	public void process(QuiltLauncher launcher, GamePatchContext context) {
 		for (String brandClassName : new String[] {
 				"net.minecraft.client.ClientBrandRetriever",
 				"net.minecraft.server.MinecraftServer"
 		}) {
-			ClassNode brandClass = readClass(classSource.apply(brandClassName));
+			ClassNode brandClass = context.getClassNode(brandClassName);
 
 			if (brandClass != null) {
 				if (applyBrandingPatch(brandClass)) {
-					classEmitter.accept(brandClass);
+					context.addPatchedClass(brandClass);
 				}
 			}
 		}

minecraft/src/main/java/org/quiltmc/loader/impl/game/minecraft/patch/EntrypointPatch.java

@@ -39,7 +39,7 @@
 import org.objectweb.asm.tree.MethodNode;
 import org.objectweb.asm.tree.VarInsnNode;
 import org.quiltmc.loader.impl.entrypoint.GamePatch;
-
+import org.quiltmc.loader.impl.entrypoint.GamePatchContext;
 import org.quiltmc.loader.impl.fabric.util.version.VersionPredicateParser;
 import org.quiltmc.loader.impl.game.minecraft.MinecraftGameProvider;
 import org.quiltmc.loader.impl.launch.common.QuiltLauncher;
@@ -65,7 +65,7 @@ private void finishEntrypoint(EnvType type, ListIterator<AbstractInsnNode> it) {
 	}
 
 	@Override
-	public void process(QuiltLauncher launcher, Function<String, ClassReader> classSource, Consumer<ClassNode> classEmitter) {
+	public void process(QuiltLauncher launcher, GamePatchContext context) {
 		EnvType type = launcher.getEnvironmentType();
 		String entrypoint = launcher.getEntrypoint();
 		Version gameVersion = getGameVersion();
@@ -77,7 +77,8 @@ public void process(QuiltLauncher launcher, Function<String, ClassReader> classS
 		String gameEntrypoint = null;
 		boolean serverHasFile = true;
 		boolean isApplet = entrypoint.contains("Applet");
-		ClassNode mainClass = readClass(classSource.apply(entrypoint));
+		ClassNode mainClass = context.getClassNode(entrypoint);
+		Function<String, ClassReader> classSource = context::getClassSourceReader;
 
 		if (mainClass == null) {
 			throw new RuntimeException("Could not load main class " + entrypoint + "!");
@@ -192,7 +193,7 @@ public void process(QuiltLauncher launcher, Function<String, ClassReader> classS
 		if (gameEntrypoint.equals(entrypoint) || is20w22aServerOrHigher) {
 			gameClass = mainClass;
 		} else {
-			gameClass = readClass(classSource.apply(gameEntrypoint));
+			gameClass = context.getClassNode(gameEntrypoint);
 			if (gameClass == null) throw new RuntimeException("Could not load game class " + gameEntrypoint + "!");
 		}
 
@@ -520,9 +521,9 @@ public void process(QuiltLauncher launcher, Function<String, ClassReader> classS
 		}
 
 		if (gameClass != mainClass) {
-			classEmitter.accept(gameClass);
+			context.addPatchedClass(gameClass);
 		} else {
-			classEmitter.accept(mainClass);
+			context.addPatchedClass(mainClass);
 		}
 
 		if (isApplet) {

src/main/java/org/quiltmc/loader/impl/entrypoint/GamePatch.java

@@ -128,6 +128,12 @@ protected boolean isPublicInstance(int access) {
 		return ((access & 0x0F) == (Opcodes.ACC_PUBLIC | 0 /* non-static */));
 	}
 
-	public abstract void process(QuiltLauncher launcher, Function<String, ClassReader> classSource, Consumer<ClassNode> classEmitter);
+	public void process(QuiltLauncher launcher, Function<String, ClassReader> classSource, Consumer<ClassNode> classEmitter) {
+		throw new AbstractMethodError(getClass() + " must override one of the 'process' methods!");
+	}
+
+	public void process(QuiltLauncher launcher, GamePatchContext context) {
+		process(launcher, context::getClassSourceReader, context::addPatchedClass);
+	}
 }
 

src/main/java/org/quiltmc/loader/impl/entrypoint/GamePatchContext.java

@@ -0,0 +1,20 @@
+package org.quiltmc.loader.impl.entrypoint;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.tree.ClassNode;
+import org.quiltmc.loader.impl.util.QuiltLoaderInternal;
+import org.quiltmc.loader.impl.util.QuiltLoaderInternalType;
+
+@ApiStatus.NonExtendable
+@QuiltLoaderInternal(QuiltLoaderInternalType.LEGACY_EXPOSED)
+public interface GamePatchContext {
+
+	/** @return A {@link ClassReader} which reads the original class file. */
+	ClassReader getClassSourceReader(String className);
+
+	/** @return A {@link ClassNode}, which may have already been modified by another {@link GamePatch}. */
+	ClassNode getClassNode(String className);
+
+	void addPatchedClass(ClassNode patchedClass);
+}

src/main/java/org/quiltmc/loader/impl/entrypoint/GameTransformer.java

@@ -95,8 +95,45 @@ public void locateEntrypoints(QuiltLauncher launcher, List<Path> gameJars) {
 				}
 			};
 
+			Map<String, ClassNode> tempClassNodes = new HashMap<>();
+			Map<String, ClassNode> addedClassNodes = new HashMap<>();
+
+			GamePatchContext context = new GamePatchContext() {
+
+				@Override
+				public ClassReader getClassSourceReader(String className) {
+					return classSource.apply(className);
+				}
+
+				@Override
+				public ClassNode getClassNode(String className) {
+					ClassNode node = tempClassNodes.get(className);
+					if (node == null) {
+						node = GamePatch.readClass(getClassSourceReader(className));
+						tempClassNodes.put(className, node);
+					}
+					return node;
+				}
+
+				@Override
+				public void addPatchedClass(ClassNode node) {
+					String key = node.name.replace('/', '.');
+					if (tempClassNodes.get(key) == node) {
+						addedClassNodes.put(key, node);
+					} else if (addedClassNodes.containsKey(key)) {
+						throw new RuntimeException("Duplicate addPatchedClasses call: " + key);
+					} else {
+						GameTransformer.this.addPatchedClass(node);
+					}
+				}
+			};
+
 			for (GamePatch patch : patches) {
-				patch.process(launcher, classSource, this::addPatchedClass);
+				patch.process(launcher, context);
+			}
+
+			for (ClassNode node : addedClassNodes.values()) {
+				addPatchedClass(node);
 			}
 		} catch (IOException e) {
 			throw ExceptionUtil.wrap(e);