Make state_definition_construct degrade gracefully if map is used like a hashmap

Related: #452

Author: embeddedt

common/src/main/java/org/embeddedt/modernfix/blockstate/FakeStateMap.java

@@ -1,5 +1,6 @@
 package org.embeddedt.modernfix.blockstate;
 
+import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
 import net.minecraft.world.level.block.state.properties.Property;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -14,6 +15,7 @@
  */
 public class FakeStateMap<S> implements Map<Map<Property<?>, Comparable<?>>, S> {
     private final Map<Property<?>, Comparable<?>>[] keys;
+    private Map<Map<Property<?>, Comparable<?>>, S> fastLookup;
     private final Object[] values;
     private int usedSlots;
     public FakeStateMap(int numStates) {
@@ -34,22 +36,39 @@ public boolean isEmpty() {
 
     @Override
     public boolean containsKey(Object o) {
-        throw new UnsupportedOperationException();
+        return getFastLookup().containsKey(o);
     }
 
     @Override
     public boolean containsValue(Object o) {
-        throw new UnsupportedOperationException();
+        return getFastLookup().containsValue(o);
+    }
+
+    @SuppressWarnings("unchecked")
+    private Map<Map<Property<?>, Comparable<?>>, S> getFastLookup() {
+        if(fastLookup == null) {
+            var map = new Object2ObjectOpenHashMap<Map<Property<?>, Comparable<?>>, S>(usedSlots);
+            Map<Property<?>, Comparable<?>>[] keys = this.keys;
+            Object[] values = this.values;
+            for(int i = 0; i < usedSlots; i++) {
+                map.put(keys[i], (S)values[i]);
+            }
+            fastLookup = map;
+        }
+        return fastLookup;
     }
 
     @Override
     public S get(Object o) {
-        throw new UnsupportedOperationException();
+        return getFastLookup().get(o);
     }
 
     @Nullable
     @Override
     public S put(Map<Property<?>, Comparable<?>> propertyComparableMap, S s) {
+        if(fastLookup != null) {
+            throw new IllegalStateException("Cannot populate map after fast lookup is built");
+        }
         keys[usedSlots] = propertyComparableMap;
         values[usedSlots] = s;
         usedSlots++;
@@ -70,7 +89,7 @@ public void putAll(@NotNull Map<? extends Map<Property<?>, Comparable<?>>, ? ext
 
     @Override
     public void clear() {
-        for(int i = 0; i < this.keys.length; i++) {
+        for(int i = 0; i < usedSlots; i++) {
             this.keys[i] = null;
             this.values[i] = null;
         }

common/src/main/java/org/embeddedt/modernfix/common/mixin/perf/state_definition_construct/StateDefinitionMixin.java

@@ -6,23 +6,25 @@
 import net.minecraft.world.level.block.state.properties.Property;
 import org.embeddedt.modernfix.annotation.RequiresMod;
 import org.embeddedt.modernfix.blockstate.FakeStateMap;
-import org.embeddedt.modernfix.blockstate.FerriteCorePostProcess;
-import org.embeddedt.modernfix.platform.ModernFixPlatformHooks;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
-import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.ModifyVariable;
-import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
 
 import java.util.Map;
 
+// This optimization requires FerriteCore to be worthwhile, otherwise the FakeStateMap degrades to hash internally
 @Mixin(StateDefinition.class)
 @RequiresMod("ferritecore")
 public class StateDefinitionMixin<O, S extends StateHolder<O, S>> {
     @Shadow @Final private ImmutableSortedMap<String, Property<?>> propertiesByName;
 
+    /**
+     * @author embeddedt
+     * @reason write states into a custom array map for fast iteration by FerriteCore, no need to waste time hashing
+     * and growing
+     */
     @ModifyVariable(method = "<init>", at = @At(value = "STORE", ordinal = 0), ordinal = 1, index = 8)
     private Map<Map<Property<?>, Comparable<?>>, S> useArrayMap(Map<Map<Property<?>, Comparable<?>>, S> in) {
         int numStates = 1;
@@ -31,11 +33,4 @@ private Map<Map<Property<?>, Comparable<?>>, S> useArrayMap(Map<Map<Property<?>,
         }
         return new FakeStateMap<>(numStates);
     }
-
-    @Inject(method = "<init>", at = @At("TAIL"))
-    private void postProcess(CallbackInfo ci) {
-        // keep in dev only until upstream FC releases
-        if(ModernFixPlatformHooks.INSTANCE.isDevEnv())
-            FerriteCorePostProcess.postProcess((StateDefinition<O, S>)(Object)this);
-    }
 }