Add a way to look up which sources specify a certain target

parser/src/main/java/net/neoforged/accesstransformer/parser/Target.java

@@ -3,11 +3,26 @@
 public sealed interface Target {
     String className();
 
+    /**
+     * Checks whether this target matches the given target description.
+     *
+     * @param className The FQN of the class containing the target
+     * @param type The type of the target
+     * @param targetName The name of the target (ignored for {@link TargetType#CLASS} and wildcard targets)
+     * @return whether this target matches the given target description
+     */
+    boolean matches(final String className, final TargetType type, final String targetName);
+
     record ClassTarget(String className) implements Target {
         @Override
         public String toString() {
             return className() + " CLASS";
         }
+
+        @Override
+        public boolean matches(final String className, final TargetType type, final String targetName) {
+            return type == TargetType.CLASS && this.className.equals(className);
+        }
     }
 
     record InnerClassTarget(String className, String innerName) implements Target {
@@ -16,33 +31,58 @@ public String toString() {
             int idx = innerName().lastIndexOf('$');
             return className() + " INNERCLASS " + innerName().substring(idx + 1);
         }
+
+        @Override
+        public boolean matches(final String className, final TargetType type, final String targetName) {
+            return type == TargetType.CLASS && this.innerName.equals(className);
+        }
     }
 
     record FieldTarget(String className, String fieldName) implements Target {
         @Override
         public String toString() {
             return className() + " FIELD " + fieldName();
         }
+
+        @Override
+        public boolean matches(final String className, final TargetType type, final String targetName) {
+            return type == TargetType.FIELD && this.className.equals(className) && this.fieldName.equals(targetName);
+        }
     }
 
     record MethodTarget(String className, String methodName, String methodDescriptor) implements Target {
         @Override
         public String toString() {
             return className() + " METHOD " + methodName() + methodDescriptor();
         }
+
+        @Override
+        public boolean matches(final String className, final TargetType type, final String targetName) {
+            return type == TargetType.METHOD && this.className.equals(className) && targetName.equals(this.methodName + this.methodDescriptor);
+        }
     }
 
     record WildcardMethodTarget(String className) implements Target {
         @Override
         public String toString() {
             return className() + " METHODWILDCARD";
         }
+
+        @Override
+        public boolean matches(final String className, final TargetType type, final String targetName) {
+            return type == TargetType.METHOD && this.className.equals(className);
+        }
     }
 
     record WildcardFieldTarget(String className) implements Target {
         @Override
         public String toString() {
             return className() + " FIELDWILDCARD";
         }
+
+        @Override
+        public boolean matches(final String className, final TargetType type, final String targetName) {
+            return type == TargetType.FIELD && this.className.equals(className);
+        }
     }
 }

src/main/java/net/neoforged/accesstransformer/TargetType.java → parser/src/main/java/net/neoforged/accesstransformer/parser/TargetType.java

@@ -1,4 +1,4 @@
-package net.neoforged.accesstransformer;
+package net.neoforged.accesstransformer.parser;
 
 public enum TargetType {
     FIELD, METHOD, CLASS;

src/main/java/net/neoforged/accesstransformer/AccessTransformer.java

@@ -1,9 +1,9 @@
 package net.neoforged.accesstransformer;
 
 import net.neoforged.accesstransformer.parser.Target;
+import net.neoforged.accesstransformer.parser.TargetType;
 import net.neoforged.accesstransformer.parser.Transformation;
 import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.Type;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.Marker;

src/main/java/net/neoforged/accesstransformer/AccessTransformerEngineImpl.java

@@ -1,6 +1,7 @@
 package net.neoforged.accesstransformer;
 
 import net.neoforged.accesstransformer.api.AccessTransformerEngine;
+import net.neoforged.accesstransformer.parser.TargetType;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
 import org.objectweb.asm.tree.ClassNode;
@@ -82,4 +83,9 @@ public Set<Type> getTargets() {
     public boolean containsClassTarget(Type type) {
         return masterList.containsClassTarget(type);
     }
+
+    @Override
+    public Set<String> getSourcesForTarget(final String className, final TargetType type, final String targetName) {
+        return masterList.getSourcesForTarget(className, type, targetName);
+    }
 }

src/main/java/net/neoforged/accesstransformer/AccessTransformerList.java

@@ -2,6 +2,7 @@
 
 import net.neoforged.accesstransformer.parser.AccessTransformerFiles;
 import net.neoforged.accesstransformer.parser.Target;
+import net.neoforged.accesstransformer.parser.TargetType;
 import net.neoforged.accesstransformer.parser.Transformation;
 import org.objectweb.asm.Type;
 
@@ -10,6 +11,7 @@
 import java.net.URISyntaxException;
 import java.nio.file.Path;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -57,4 +59,19 @@ public Map<TargetType, Map<String, AccessTransformer<?>>> getTransformersForTarg
                         Collectors.toMap((Function<AccessTransformer<?>, String>) AccessTransformer::targetName, Function.<AccessTransformer<?>>identity())
                 ));
     }
+
+    public Set<String> getSourcesForTarget(final String className, final TargetType type, final String targetName) {
+        return atFiles.getAccessTransformers()
+                .entrySet()
+                .stream()
+                .filter(e -> e.getKey().matches(className, type, targetName))
+                .map(Map.Entry::getValue)
+                .map(Transformation::origins)
+                .map(HashSet::new)
+                .reduce((s1, s2) -> {
+                    s1.addAll(s2);
+                    return s1;
+                })
+                .orElse(null);
+    }
 }

src/main/java/net/neoforged/accesstransformer/FieldAccessTransformer.java

@@ -1,6 +1,7 @@
 package net.neoforged.accesstransformer;
 
 import net.neoforged.accesstransformer.parser.Target;
+import net.neoforged.accesstransformer.parser.TargetType;
 import net.neoforged.accesstransformer.parser.Transformation;
 import org.objectweb.asm.tree.FieldNode;
 

src/main/java/net/neoforged/accesstransformer/MethodAccessTransformer.java

@@ -1,6 +1,7 @@
 package net.neoforged.accesstransformer;
 
 import net.neoforged.accesstransformer.parser.Target;
+import net.neoforged.accesstransformer.parser.TargetType;
 import net.neoforged.accesstransformer.parser.Transformation;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.tree.MethodNode;

src/main/java/net/neoforged/accesstransformer/WildcardAccessTransformer.java

@@ -1,6 +1,7 @@
 package net.neoforged.accesstransformer;
 
 import net.neoforged.accesstransformer.parser.Target;
+import net.neoforged.accesstransformer.parser.TargetType;
 import net.neoforged.accesstransformer.parser.Transformation;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.tree.ClassNode;

src/main/java/net/neoforged/accesstransformer/api/AccessTransformerEngine.java

@@ -1,6 +1,7 @@
 package net.neoforged.accesstransformer.api;
 
 import net.neoforged.accesstransformer.AccessTransformerEngineImpl;
+import net.neoforged.accesstransformer.parser.TargetType;
 import org.objectweb.asm.Type;
 import org.objectweb.asm.tree.ClassNode;
 
@@ -51,6 +52,18 @@ public interface AccessTransformerEngine {
      */
     boolean containsClassTarget(Type type);
 
+    /**
+     * Looks up AT file sources of entries matching the given target
+     *
+     * @param className the class containing the target
+     * @param type the type of the target
+     * @param targetName the target's name (null for class targets, full descriptor for method targets, name for field targets)
+     * @return The list of sources specifying the given target or null if none apply
+     */
+    default Set<String> getSourcesForTarget(final String className, final TargetType type, final String targetName) {
+        return null;
+    }
+
     /**
      * Attempts to transform the given {@code classNode}, and apply ATs, if any.
      * @param classNode the class to transform

src/test/java/net/neoforged/accesstransformer/test/AccessTransformerPresenceTest.java

@@ -0,0 +1,36 @@
+package net.neoforged.accesstransformer.test;
+
+import net.neoforged.accesstransformer.AccessTransformerList;
+import net.neoforged.accesstransformer.parser.TargetType;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.URISyntaxException;
+import java.nio.file.Path;
+import java.util.Set;
+
+public class AccessTransformerPresenceTest {
+    @Test
+    public void testSourceLookup() throws IOException, URISyntaxException {
+        final AccessTransformerList atLoader = new AccessTransformerList();
+
+        Path filePath = Path.of(getClass().getClassLoader().getResource("forge_at.cfg").toURI());
+        atLoader.loadFromPath(filePath);
+
+        String sourcePrefix = filePath.toString();
+
+        // Class
+        Assertions.assertEquals(Set.of(sourcePrefix + ":99"), atLoader.getSourcesForTarget("net.minecraft.item.crafting.RecipeTippedArrow", TargetType.CLASS, null));
+        // Inner class
+        Assertions.assertEquals(Set.of(sourcePrefix + ":76"), atLoader.getSourcesForTarget("net.minecraft.world.gen.structure.StructureStrongholdPieces$Stronghold", TargetType.CLASS, null));
+        // Method
+        Assertions.assertEquals(Set.of(sourcePrefix + ":6"), atLoader.getSourcesForTarget("net.minecraft.block.Block", TargetType.METHOD, "func_149752_b(F)Lnet/minecraft/block/Block;"));
+        // Field
+        Assertions.assertEquals(Set.of(sourcePrefix + ":22"), atLoader.getSourcesForTarget("net.minecraft.entity.EntityTrackerEntry", TargetType.FIELD, "field_73134_o"));
+        // Method wildcard
+        Assertions.assertEquals(Set.of(sourcePrefix + ":29"), atLoader.getSourcesForTarget("net.minecraft.world.biome.Biome", TargetType.METHOD, "this_is_ignored(F)Ldoes/not/Matter;"));
+        // Field wildcard
+        Assertions.assertEquals(Set.of(sourcePrefix + ":51"), atLoader.getSourcesForTarget("net.minecraft.world.biome.BiomeDecorator", TargetType.FIELD, "this_is_ignored"));
+    }
+}