handle random values from various random sources

PaperMC · Jul 26, 2023 · 3807699 · 3807699
1 parent 3252e8d
commit 3807699
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diff --git a/src/main/java/io/papermc/codebook/lvt/LvtAssignmentSuggester.java b/src/main/java/io/papermc/codebook/lvt/LvtAssignmentSuggester.java
@@ -22,6 +22,9 @@
 
 package io.papermc.codebook.lvt;
 
+import java.util.Set;
+import java.util.function.Function;
+import java.util.function.Predicate;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.objectweb.asm.Type;
 import org.objectweb.asm.tree.MethodInsnNode;
@@ -36,6 +39,11 @@ private LvtAssignmentSuggester() {}
             return suggested;
         }
 
+        suggested = suggestNameForRandomSource(methodName, insn);
+        if (suggested != null) {
+            return suggested;
+        }
+
         suggested = suggestNameFromGetter(methodName);
         if (suggested != null) {
             return suggested;
@@ -80,6 +88,49 @@ public static String suggestNameFromRecord(final String methodName) {
         return methodName;
     }
 
+    private static @Nullable String suggestNameForRandomSource(final String methodName, final MethodInsnNode insn) {
+        if (!"net/minecraft/util/RandomSource".equals(insn.owner) || insn.desc == null) {
+            return null;
+        }
+
+        if (!methodName.startsWith("next") || "next".equals(methodName)) {
+            return null;
+        }
+
+        final Function<Set<String>, Predicate<String>> equalsAny = strings -> s -> strings.stream().anyMatch(Predicate.isEqual(s));
+        final @Nullable Predicate<String> expectedNextWord = switch (Type.getReturnType(insn.desc).getDescriptor()) {
+            case "B" -> equalsAny.apply(Set.of("Byte"));
+            case "C" -> equalsAny.apply(Set.of("Char", "Character"));
+            case "D" -> equalsAny.apply(Set.of("Double"));
+            case "F" -> equalsAny.apply(Set.of("Float"));
+            case "I" -> equalsAny.apply(Set.of("Int", "Integer"));
+            case "L" -> equalsAny.apply(Set.of("Long"));
+            case "S" -> equalsAny.apply(Set.of("Short"));
+            case "Z" -> equalsAny.apply(Set.of("Bool", "Boolean"));
+            default -> null;
+        };
+        if (expectedNextWord == null) {
+            return null;
+        }
+
+        final StringBuilder nextWord = new StringBuilder();
+        for (int i = "next".length(); i < methodName.length(); i++) {
+            final char ch = methodName.charAt(i);
+            if (nextWord.isEmpty()) {
+                nextWord.append(ch);
+            } else if (!Character.isUpperCase(ch)) {
+                nextWord.append(ch);
+            } else {
+                break;
+            }
+        }
+
+        if (expectedNextWord.test(nextWord.toString())) {
+            return "random" + nextWord;
+        }
+        return null;
+    }
+
     private static @Nullable String suggestNameFromGetter(final String methodName) {
         if (!methodName.startsWith("get") || methodName.equals("get")) {
             // If the method isn't `get<Thing>` - or if the method is just `get`

diff --git a/src/test/resources/io/papermc/codebook/lvt/LvtAssignmentSuggesterTest.csv b/src/test/resources/io/papermc/codebook/lvt/LvtAssignmentSuggesterTest.csv
@@ -45,3 +45,11 @@ getOrCreate,io/paper/Paper,()Ljava/lang/String;,
 gettingBetter,io/paper/Paper,()Ljava/lang/String;,
 as,io/paper/paper,()Ljava/lang/String;,
 ass,io/paper/paper,()Ljava/lang/String;,
+# random methods,,,
+nextInt,net/minecraft/util/RandomSource,()I,randomInt
+nextInteger,net/minecraft/util/RandomSource,()I,randomInteger
+nextInt,net/minecraft/util/RandomSource,()L,
+nextInt,io/paper/Paper,()I,
+nextIntBetween,net/minecraft/util/RandomSource,(II)I,randomInt
+nextIntBetween,net/minecraft/util/RandomSource,(II)L,
+nextBoolean,net/minecraft/util/RandomSource,()Z,randomBoolean