Handle fluent getters for primitive return types (#9)

Co-authored-by: MiniDigger | Martin <admin@benndorf.dev>

Author: Machine-Maker

codebook-lvt/src/main/java/io/papermc/codebook/lvt/LvtTypeSuggester.java

@@ -104,7 +104,8 @@ private String suggestNameFromClassType(final ClassType type) throws IOException
         // TODO Try to determine name from signature, rather than just descriptor
         final @Nullable ClassData typeClass = this.context.getContextProvider().findClass(type);
         if (typeClass != null) {
-            if (typeClass.doesExtendOrImplement(this.listClass) && !typeClass.name().startsWith("net/minecraft/nbt/")) { // exclude nbt lists
+            if (typeClass.doesExtendOrImplement(this.listClass)
+                    && !typeClass.name().startsWith("net/minecraft/nbt/")) { // exclude nbt lists
                 return "list";
             } else if (typeClass.doesExtendOrImplement(this.setClass)) {
                 return "set";

codebook-lvt/src/main/java/io/papermc/codebook/lvt/RootLvtSuggester.java

@@ -33,6 +33,7 @@
 import dev.denwav.hypo.model.data.MethodData;
 import dev.denwav.hypo.model.data.MethodDescriptor;
 import dev.denwav.hypo.model.data.types.JvmType;
+import io.papermc.codebook.lvt.suggestion.FluentGetterSuggester;
 import io.papermc.codebook.lvt.suggestion.GenericSuggester;
 import io.papermc.codebook.lvt.suggestion.LvtSuggester;
 import io.papermc.codebook.lvt.suggestion.MathSuggester;
@@ -76,6 +77,7 @@ public final class RootLvtSuggester extends AbstractModule implements LvtSuggest
             SingleVerbSuggester.class,
             VerbPrefixBooleanSuggester.class,
             SingleVerbBooleanSuggester.class,
+            FluentGetterSuggester.class,
             RecordComponentSuggester.class,
             GenericSuggester.class);
 

codebook-lvt/src/main/java/io/papermc/codebook/lvt/suggestion/FluentGetterSuggester.java

@@ -0,0 +1,97 @@
+/*
+ * codebook is a remapper utility for the PaperMC project.
+ *
+ * Copyright (c) 2023 Kyle Wood (DenWav)
+ *                    Contributors
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 3 only, no later versions.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
+ * USA
+ */
+
+package io.papermc.codebook.lvt.suggestion;
+
+import dev.denwav.hypo.model.data.types.PrimitiveType;
+import io.papermc.codebook.lvt.suggestion.context.ContainerContext;
+import io.papermc.codebook.lvt.suggestion.context.method.MethodCallContext;
+import io.papermc.codebook.lvt.suggestion.context.method.MethodInsnContext;
+import java.io.IOException;
+import java.util.Set;
+import java.util.function.IntPredicate;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.AbstractInsnNode;
+import org.objectweb.asm.tree.InsnList;
+
+public class FluentGetterSuggester implements LvtSuggester {
+
+    private static final Set<String> ignored = Set.of(
+            "byteValue",
+            "shortValue",
+            "intValue",
+            "longValue",
+            "floatValue",
+            "doubleValue",
+            "booleanValue",
+            "charValue",
+            "get");
+
+    // 3 instructions, load "this" local var, getfield, return - TODO maybe if there is a CAST,
+    private static final IntPredicate[] OPCODES_IN_ORDER = new IntPredicate[] {
+        i -> i == Opcodes.ALOAD, i -> i == Opcodes.GETFIELD, i -> i >= Opcodes.IRETURN && i <= Opcodes.RETURN
+    };
+
+    @Override
+    public @Nullable String suggestFromMethod(
+            final MethodCallContext call, final MethodInsnContext insn, final ContainerContext container)
+            throws IOException {
+        // I think it's best to only work with primitive types here, as other types should already have names
+        // and this dramatically cuts down on the number of methods analyzed because we aren't filtering by
+        // method name
+        if (!(call.data().returnType() instanceof PrimitiveType)
+                || !call.data().params().isEmpty()) {
+            return null;
+        }
+        int opcodeIndex = 0;
+        final InsnList instructions = call.node().instructions;
+        if (instructions.size() == 0) {
+            return null;
+        }
+        for (final AbstractInsnNode methodInsn : instructions) {
+            if (methodInsn.getOpcode() == -1) {
+                continue;
+            }
+            if (opcodeIndex == OPCODES_IN_ORDER.length) {
+                break; // matched the correct order
+            }
+            if (OPCODES_IN_ORDER[opcodeIndex].test(methodInsn.getOpcode())) {
+                opcodeIndex++;
+            } else {
+                return null;
+            }
+        }
+        if (call.data().isStatic()) { // limit static matches
+            if ("java/lang/System".equals(insn.node().owner) && "currentTimeMillis".equals(insn.node().name)) {
+                return "currentTimeMillis";
+            }
+        } else {
+            final String name = call.data().name();
+            if (ignored.contains(name)) {
+                return null;
+            }
+            return name;
+        }
+        return null;
+    }
+}

src/test/java/io/papermc/codebook/lvt/LvtAssignmentSuggesterTest.java

@@ -56,7 +56,9 @@
 import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
 import org.objectweb.asm.Opcodes;
+import org.objectweb.asm.tree.InsnList;
 import org.objectweb.asm.tree.MethodInsnNode;
+import org.objectweb.asm.tree.MethodNode;
 
 @ExtendWith(MockitoExtension.class)
 @MockitoSettings(strictness = Strictness.LENIENT)
@@ -125,6 +127,10 @@ void testSuggester(
         when(method.param(anyInt())).thenCallRealMethod();
         when(method.returnType()).thenCallRealMethod();
 
+        final MethodNode node = new MethodNode(Opcodes.ASM9, methodName, methodDescriptor, null, null);
+        node.instructions = new InsnList();
+        when(method.getNode()).thenReturn(node);
+
         if (methodOwner.equals(HypoModelUtil.normalizedClassName(RANDOM_SOURCE_TYPE.asInternalName()))) {
             when(owner.doesExtendOrImplement(this.randomSourceClass)).thenReturn(true);
         } else {