From 8dfb97fd87cb9de71423fbf2be7d9645b5bfff4c Mon Sep 17 00:00:00 2001
From: shedaniel <daniel@shedaniel.me>
Date: Wed, 30 Dec 2020 20:24:09 +0800
Subject: [PATCH] Add DeferredRegister

---
 .../registry/DeferredRegister.java            | 130 ++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 common/src/main/java/me/shedaniel/architectury/registry/DeferredRegister.java

diff --git a/common/src/main/java/me/shedaniel/architectury/registry/DeferredRegister.java b/common/src/main/java/me/shedaniel/architectury/registry/DeferredRegister.java
new file mode 100644
index 00000000..55d56b9f
--- /dev/null
+++ b/common/src/main/java/me/shedaniel/architectury/registry/DeferredRegister.java
@@ -0,0 +1,130 @@
+/*
+ * This file is part of architectury.
+ * Copyright (C) 2020 shedaniel
+ *
+ * This program 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; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program 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 program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+package me.shedaniel.architectury.registry;
+
+import com.google.common.base.Objects;
+import net.minecraft.resources.ResourceKey;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.util.LazyLoadedValue;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Supplier;
+
+public class DeferredRegister<T> {
+    private final Supplier<Registries> registriesSupplier;
+    private final ResourceKey<net.minecraft.core.Registry<T>> key;
+    private final List<Entry<T>> entries = new ArrayList<>();
+    private boolean registered = false;
+    
+    private DeferredRegister(Supplier<Registries> registriesSupplier, ResourceKey<net.minecraft.core.Registry<T>> key) {
+        this.registriesSupplier = registriesSupplier;
+        this.key = key;
+    }
+    
+    @NotNull
+    public static <T> DeferredRegister<T> create(Registries registries, ResourceKey<net.minecraft.core.Registry<T>> key) {
+        return new DeferredRegister<>(() -> registries, key);
+    }
+    
+    @NotNull
+    public static <T> DeferredRegister<T> create(Supplier<Registries> registries, ResourceKey<net.minecraft.core.Registry<T>> key) {
+        return new DeferredRegister<>(registries, key);
+    }
+    
+    @NotNull
+    public static <T> DeferredRegister<T> create(LazyLoadedValue<Registries> registries, ResourceKey<net.minecraft.core.Registry<T>> key) {
+        return create(registries::get, key);
+    }
+    
+    public RegistrySupplier<T> register(ResourceLocation id, Supplier<T> supplier) {
+        Entry<T> entry = new Entry<>(id, supplier);
+        this.entries.add(entry);
+        if (registered) {
+            Registry<T> registry = registriesSupplier.get().get(key);
+            entry.value = registry.registerSupplied(entry.id, entry.supplier);
+        }
+        return entry;
+    }
+    
+    public void register() {
+        if (registered) {
+            throw new IllegalStateException("Cannot register a deferred register twice!");
+        }
+        registered = true;
+        Registry<T> registry = registriesSupplier.get().get(key);
+        for (Entry<T> entry : entries) {
+            entry.value = registry.registerSupplied(entry.id, entry.supplier);
+        }
+    }
+    
+    private class Entry<T> implements RegistrySupplier<T> {
+        private final ResourceLocation id;
+        private final Supplier<T> supplier;
+        private RegistrySupplier<T> value;
+    
+        public Entry(ResourceLocation id, Supplier<T> supplier) {
+            this.id = id;
+            this.supplier = supplier;
+        }
+    
+        @Override
+        public @NotNull ResourceLocation getRegistryId() {
+            return key.location();
+        }
+    
+        @Override
+        public @NotNull ResourceLocation getId() {
+            return id;
+        }
+    
+        @Override
+        public boolean isPresent() {
+            return value != null && value.isPresent();
+        }
+    
+        @Override
+        public T get() {
+            if (isPresent()) {
+                return value.get();
+            }
+            throw new NullPointerException("Registry Object not present: " + this.id);
+        }
+    
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(getRegistryId(), getId());
+        }
+    
+        @Override
+        public boolean equals(Object obj) {
+            if (this == obj) return true;
+            if (!(obj instanceof RegistrySupplier)) return false;
+            RegistrySupplier<?> other = (RegistrySupplier<?>) obj;
+            return other.getRegistryId().equals(getRegistryId()) && other.getId().equals(getId());
+        }
+    
+        @Override
+        public String toString() {
+            return getRegistryId().toString() + "@" + id.toString();
+        }
+    }
+}