Add overwriting screen handler factory (#2373)

This adds `FabricScreenHandlerFactory` (interface-injected to `NamedScreenHandlerFactory`).

This also fixes a crash when passing `SimpleNamedScreenHandlerFactory` that wraps a `ExtendedScreenHandlerFactory`. The mixin now un-wraps the factory.

fabric-screen-handler-api-v1/src/main/java/net/fabricmc/fabric/api/screenhandler/v1/FabricScreenHandlerFactory.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.api.screenhandler.v1;
+
+/**
+ * An extension to {@link net.minecraft.screen.NamedScreenHandlerFactory}.
+ * Unlike {@link ExtendedScreenHandlerFactory}, this can be used by any screen
+ * handlers, and is implemented via interface injection.
+ */
+public interface FabricScreenHandlerFactory {
+	/**
+	 * {@return whether the server should send {@link
+	 * net.minecraft.network.packet.s2c.play.CloseScreenS2CPacket} when opening the screen}
+	 *
+	 * <p>In vanilla, opening a new screen will always send the close screen packet.
+	 * This, among other things, causes the mouse cursor to move to the center of the screen,
+	 * which might not be expected in some cases. If this returns {@code false}, the packet
+	 * is not sent to the client, stopping the behavior.
+	 */
+	default boolean shouldCloseCurrentScreen() {
+		return true;
+	}
+}

fabric-screen-handler-api-v1/src/main/java/net/fabricmc/fabric/api/screenhandler/v1/package-info.java

@@ -38,6 +38,16 @@
  * Screen handlers can be opened using
  * {@link net.minecraft.entity.player.PlayerEntity#openHandledScreen(net.minecraft.screen.NamedScreenHandlerFactory)}.
  * Note that calling it on the logical client does nothing. To open an extended screen handler, the factory passed in
- * should be an {@link net.fabricmc.fabric.api.screenhandler.v1.ExtendedScreenHandlerFactory}.
+ * should be an {@link net.fabricmc.fabric.api.screenhandler.v1.ExtendedScreenHandlerFactory}, or a
+ * {@link net.minecraft.screen.SimpleNamedScreenHandlerFactory} that wraps such factory.
+ *
+ * <h2>Overwriting screen handlers</h2>
+ * You might have noticed that calling {@link net.minecraft.entity.player.PlayerEntity#openHandledScreen(net.minecraft.screen.NamedScreenHandlerFactory) openHandledScreen} while on another screen will move
+ * the cursor to the center of the screen. This is because the current screen gets closed before
+ * opening the screen, resetting the cursor position. Since this behavior can be problematic,
+ * this API provides a way to disable this. By overriding {@link
+ * net.fabricmc.fabric.api.screenhandler.v1.FabricScreenHandlerFactory#shouldCloseCurrentScreen()}
+ * on the screen handler factory to return {@code false} and passing that to the {@code
+ * openHandledScreen} method, it will stop closing the screen and instead "overwrites" it.
  */
 package net.fabricmc.fabric.api.screenhandler.v1;

fabric-screen-handler-api-v1/src/main/java/net/fabricmc/fabric/mixin/screenhandler/NamedScreenHandlerFactoryMixin.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.mixin.screenhandler;
+
+import org.spongepowered.asm.mixin.Mixin;
+
+import net.minecraft.screen.NamedScreenHandlerFactory;
+
+import net.fabricmc.fabric.api.screenhandler.v1.FabricScreenHandlerFactory;
+
+@Mixin(NamedScreenHandlerFactory.class)
+public interface NamedScreenHandlerFactoryMixin extends FabricScreenHandlerFactory {
+}

fabric-screen-handler-api-v1/src/main/java/net/fabricmc/fabric/mixin/screenhandler/ServerPlayerEntityMixin.java

@@ -30,8 +30,9 @@ import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
 import net.minecraft.network.Packet;
 import net.minecraft.screen.NamedScreenHandlerFactory;
 import net.minecraft.screen.ScreenHandler;
-import net.minecraft.server.network.ServerPlayerEntity;
+import net.minecraft.screen.SimpleNamedScreenHandlerFactory;
 import net.minecraft.server.network.ServerPlayNetworkHandler;
+import net.minecraft.server.network.ServerPlayerEntity;
 import net.minecraft.util.Identifier;
 import net.minecraft.util.registry.Registry;
 
@@ -40,16 +41,32 @@ import net.fabricmc.fabric.api.screenhandler.v1.ExtendedScreenHandlerType;
 import net.fabricmc.fabric.impl.screenhandler.Networking;
 
 @Mixin(ServerPlayerEntity.class)
-public class ServerPlayerEntityMixin {
+public abstract class ServerPlayerEntityMixin {
 	@Shadow
 	private int screenHandlerSyncId;
 
+	@Shadow
+	public abstract void closeHandledScreen();
+
+	@Shadow
+	public abstract void closeScreenHandler();
+
 	@Unique
 	private final ThreadLocal<ScreenHandler> fabric_openedScreenHandler = new ThreadLocal<>();
 
+	@Redirect(method = "openHandledScreen(Lnet/minecraft/screen/NamedScreenHandlerFactory;)Ljava/util/OptionalInt;", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/network/ServerPlayerEntity;closeHandledScreen()V"))
+	private void fabric_closeHandledScreenIfAllowed(ServerPlayerEntity player, NamedScreenHandlerFactory factory) {
+		if (factory.shouldCloseCurrentScreen()) {
+			this.closeHandledScreen();
+		} else {
+			// Called by closeHandledScreen in vanilla
+			this.closeScreenHandler();
+		}
+	}
+
 	@Inject(method = "openHandledScreen(Lnet/minecraft/screen/NamedScreenHandlerFactory;)Ljava/util/OptionalInt;", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/network/ServerPlayNetworkHandler;sendPacket(Lnet/minecraft/network/Packet;)V"), locals = LocalCapture.CAPTURE_FAILHARD)
 	private void fabric_storeOpenedScreenHandler(NamedScreenHandlerFactory factory, CallbackInfoReturnable<OptionalInt> info, ScreenHandler handler) {
-		if (factory instanceof ExtendedScreenHandlerFactory) {
+		if (factory instanceof ExtendedScreenHandlerFactory || (factory instanceof SimpleNamedScreenHandlerFactory simpleFactory && simpleFactory.baseFactory instanceof ExtendedScreenHandlerFactory)) {
 			fabric_openedScreenHandler.set(handler);
 		} else if (handler.getType() instanceof ExtendedScreenHandlerType<?>) {
 			Identifier id = Registry.SCREEN_HANDLER.getId(handler.getType());
@@ -59,6 +76,10 @@ public class ServerPlayerEntityMixin {
 
 	@Redirect(method = "openHandledScreen(Lnet/minecraft/screen/NamedScreenHandlerFactory;)Ljava/util/OptionalInt;", at = @At(value = "INVOKE", target = "Lnet/minecraft/server/network/ServerPlayNetworkHandler;sendPacket(Lnet/minecraft/network/Packet;)V"))
 	private void fabric_replaceVanillaScreenPacket(ServerPlayNetworkHandler networkHandler, Packet<?> packet, NamedScreenHandlerFactory factory) {
+		if (factory instanceof SimpleNamedScreenHandlerFactory simpleFactory && simpleFactory.baseFactory instanceof ExtendedScreenHandlerFactory extendedFactory) {
+			factory = extendedFactory;
+		}
+
 		if (factory instanceof ExtendedScreenHandlerFactory) {
 			ScreenHandler handler = fabric_openedScreenHandler.get();
 

fabric-screen-handler-api-v1/src/main/resources/fabric-screen-handler-api-v1.accesswidener

@@ -6,3 +6,5 @@ extendable	method	net/minecraft/screen/ScreenHandlerType <init> (Lnet/minecraft/
 accessible	class	net/minecraft/client/gui/screen/ingame/HandledScreens$Provider
 accessible	method	net/minecraft/client/gui/screen/ingame/HandledScreens register (Lnet/minecraft/screen/ScreenHandlerType;Lnet/minecraft/client/gui/screen/ingame/HandledScreens$Provider;)V
 accessible	method	net/minecraft/client/gui/screen/ingame/HandledScreens getProvider (Lnet/minecraft/screen/ScreenHandlerType;)Lnet/minecraft/client/gui/screen/ingame/HandledScreens$Provider;
+
+accessible	field	net/minecraft/screen/SimpleNamedScreenHandlerFactory baseFactory Lnet/minecraft/screen/ScreenHandlerFactory;

fabric-screen-handler-api-v1/src/main/resources/fabric-screen-handler-api-v1.mixins.json

@@ -3,6 +3,7 @@
   "package": "net.fabricmc.fabric.mixin.screenhandler",
   "compatibilityLevel": "JAVA_16",
   "mixins": [
+    "NamedScreenHandlerFactoryMixin",
     "ServerPlayerEntityMixin"
   ],
   "client": [

fabric-screen-handler-api-v1/src/main/resources/fabric.mod.json

@@ -29,6 +29,9 @@
   ],
   "accessWidener": "fabric-screen-handler-api-v1.accesswidener",
   "custom": {
-    "fabric-api:module-lifecycle": "stable"
+    "fabric-api:module-lifecycle": "stable",
+    "loom:injected_interfaces": {
+      "net/minecraft/class_3908": ["net/fabricmc/fabric/api/screenhandler/v1/FabricScreenHandlerFactory"]
+    }
   }
 }