Feature: Subpack loading

api/src/main/java/org/geysermc/geyser/api/pack/ResourcePack.java

@@ -26,12 +26,15 @@
 package org.geysermc.geyser.api.pack;
 
 import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
  * Represents a resource pack sent to Bedrock clients
  * <p>
  * This representation of a resource pack only contains what
  * Geyser requires to send it to the client.
+ * <p>
+ * Optionally, a content key and/or a subpack name to load can be provided.
  */
 public interface ResourcePack {
 
@@ -59,6 +62,25 @@ public interface ResourcePack {
     @NonNull
     String contentKey();
 
+    /**
+     * Sets the content key of the resource pack. Lack of a content key can be represented by an empty string.
+     */
+    void contentKey(@NonNull String contentKey);
+
+    /**
+     * The subpack to tell Bedrock clients to load. Lack of a subpack to load is represented by an empty string.
+     *
+     * @return the subpack name, or an empty string if not set.
+     */
+    @NonNull
+    String subpackName();
+
+    /**
+     * Sets the subpack name that clients should load.
+     * It must match one of the subpacks that can be found in the manifest.
+     */
+    void subpackName(@Nullable String subpackName);
+
     /**
      * Creates a resource pack with the given {@link PackCodec}.
      *

api/src/main/java/org/geysermc/geyser/api/pack/ResourcePackManifest.java

@@ -66,6 +66,14 @@ public interface ResourcePackManifest {
     @NonNull
     Collection<? extends Dependency> dependencies();
 
+    /**
+     * Gets the subpacks of the resource pack.
+     *
+     * @return the subpacks
+     */
+    @NonNull
+    Collection<? extends Subpack> subpacks();
+
     /**
      * Represents the header of a resource pack.
      */
@@ -172,6 +180,36 @@ public interface ResourcePackManifest {
         Version version();
     }
 
+    /**
+     * Represents a subpack of a resource pack
+     */
+    interface Subpack {
+
+        /**
+         * Gets the folder name of the subpack.
+         *
+         * @return the folder name
+         */
+        String folderName();
+
+        /**
+         * Gets the name of the subpack.
+         * It can be sent to the Bedrock client alongside the pack
+         * to load a particular subpack within a resource pack.
+         *
+         * @return the subpack name
+         */
+        String name();
+
+        /**
+         * Gets the memory tier of the subpack.
+         *
+         * @return the memory tier
+         */
+
+        Float memoryTier();
+    }
+
     /**
      * Represents a version of a resource pack.
      */

core/src/main/java/org/geysermc/geyser/network/UpstreamPacketHandler.java

@@ -205,11 +205,10 @@ public class UpstreamPacketHandler extends LoggingPacketHandler {
 
         ResourcePacksInfoPacket resourcePacksInfo = new ResourcePacksInfoPacket();
         for (ResourcePack pack : this.resourcePackLoadEvent.resourcePacks()) {
-            PackCodec codec = pack.codec();
             ResourcePackManifest.Header header = pack.manifest().header();
             resourcePacksInfo.getResourcePackInfos().add(new ResourcePacksInfoPacket.Entry(
-                    header.uuid().toString(), header.version().toString(), codec.size(), pack.contentKey(),
-                    "", header.uuid().toString(), false, false));
+                    header.uuid().toString(), header.version().toString(), pack.codec().size(), pack.contentKey(),
+                    pack.subpackName(), header.uuid().toString(), false, false));
         }
         resourcePacksInfo.setForcedToAccept(GeyserImpl.getInstance().getConfig().isForceResourcePacks());
         session.sendUpstreamPacket(resourcePacksInfo);

core/src/main/java/org/geysermc/geyser/pack/GeyserResourcePack.java

@@ -25,14 +25,62 @@
 
 package org.geysermc.geyser.pack;
 
+import lombok.RequiredArgsConstructor;
+import org.checkerframework.checker.nullness.qual.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import org.geysermc.geyser.api.pack.PackCodec;
 import org.geysermc.geyser.api.pack.ResourcePack;
 import org.geysermc.geyser.api.pack.ResourcePackManifest;
 
-public record GeyserResourcePack(PackCodec codec, ResourcePackManifest manifest, String contentKey) implements ResourcePack {
+@RequiredArgsConstructor
+public class GeyserResourcePack implements ResourcePack {
 
     /**
      * The size of each chunk to use when sending the resource packs to clients in bytes
      */
     public static final int CHUNK_SIZE = 102400;
+
+    private final PackCodec codec;
+    private final ResourcePackManifest manifest;
+    private String contentKey;
+    private String subpackName;
+
+    public GeyserResourcePack(PackCodec codec, ResourcePackManifest manifest, String contentKey) {
+        this(codec, manifest);
+        this.contentKey = contentKey;
+    }
+
+    @Override
+    public @NonNull PackCodec codec() {
+        return this.codec;
+    }
+
+    @Override
+    public @NonNull ResourcePackManifest manifest() {
+        return this.manifest;
+    }
+
+    @Override
+    public @NonNull String contentKey() {
+        return this.contentKey == null ? "" : this.contentKey;
+    }
+
+    @Override
+    public void contentKey(@Nullable String contentKey) {
+        this.contentKey = contentKey;
+    }
+
+    @Override
+    public @NonNull String subpackName() {
+        return this.subpackName == null ? "" : this.subpackName;
+    }
+
+    @Override
+    public void subpackName(@Nullable String subpackName) {
+        if (manifest.subpacks().stream().anyMatch(subpack -> subpack.name().equals(subpackName))) {
+            this.subpackName = subpackName;
+        } else {
+            throw new IllegalArgumentException("A subpack with the name '" + subpackName + "' does not exist!");
+        }
+    }
 }

core/src/main/java/org/geysermc/geyser/pack/GeyserResourcePackManifest.java

@@ -37,7 +37,13 @@ import java.io.IOException;
 import java.util.Collection;
 import java.util.UUID;
 
-public record GeyserResourcePackManifest(@JsonProperty("format_version") int formatVersion, Header header, Collection<Module> modules, Collection<Dependency> dependencies) implements ResourcePackManifest {
+public record GeyserResourcePackManifest(
+    @JsonProperty("format_version") int formatVersion,
+    Header header,
+    Collection<Module> modules,
+    Collection<Dependency> dependencies,
+    Collection<Subpack> subpacks
+) implements ResourcePackManifest {
 
     public record Header(UUID uuid, Version version, String name, String description, @JsonProperty("min_engine_version") Version minimumSupportedMinecraftVersion) implements ResourcePackManifest.Header { }
 
@@ -45,6 +51,8 @@ public record GeyserResourcePackManifest(@JsonProperty("format_version") int for
 
     public record Dependency(UUID uuid, Version version) implements ResourcePackManifest.Dependency { }
 
+    public record Subpack(@JsonProperty("folder_name") String folderName, String name, @JsonProperty("memory_tier") Float memoryTier) implements ResourcePackManifest.Subpack { }
+
     @JsonDeserialize(using = Version.VersionDeserializer.class)
     public record Version(int major, int minor, int patch) implements ResourcePackManifest.Version {