Rewrite the packet metadata API based on the NMS packet

Meta, if created, will persist between creation and listening.

modules/API/src/main/java/com/comphenix/protocol/events/PacketContainer.java

@@ -17,37 +17,15 @@
 
 package com.comphenix.protocol.events;
 
-import java.io.DataInput;
+import java.io.*;
-import java.io.DataInputStream;
-import java.io.DataOutput;
-import java.io.DataOutputStream;
-import java.io.IOException;
-import java.io.ObjectInputStream;
-import java.io.ObjectOutputStream;
-import java.io.Serializable;
 import java.lang.reflect.Array;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.util.Collection;
+import java.util.*;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.UUID;
 import java.util.concurrent.ConcurrentMap;
-
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
-import org.bukkit.Material;
-import org.bukkit.Sound;
-import org.bukkit.World;
-import org.bukkit.WorldType;
-import org.bukkit.entity.Entity;
-import org.bukkit.inventory.ItemStack;
-import org.bukkit.potion.PotionEffectType;
-import org.bukkit.util.Vector;
-
 import com.comphenix.protocol.PacketType;
 import com.comphenix.protocol.PacketType.Protocol;
 import com.comphenix.protocol.injector.StructureCache;
@@ -55,41 +33,15 @@ import com.comphenix.protocol.reflect.EquivalentConverter;
 import com.comphenix.protocol.reflect.FuzzyReflection;
 import com.comphenix.protocol.reflect.ObjectWriter;
 import com.comphenix.protocol.reflect.StructureModifier;
-import com.comphenix.protocol.reflect.cloning.AggregateCloner;
+import com.comphenix.protocol.reflect.cloning.*;
 import com.comphenix.protocol.reflect.cloning.AggregateCloner.BuilderParameters;
-import com.comphenix.protocol.reflect.cloning.BukkitCloner;
-import com.comphenix.protocol.reflect.cloning.Cloner;
-import com.comphenix.protocol.reflect.cloning.CollectionCloner;
-import com.comphenix.protocol.reflect.cloning.FieldCloner;
-import com.comphenix.protocol.reflect.cloning.ImmutableDetector;
-import com.comphenix.protocol.reflect.cloning.OptionalCloner;
-import com.comphenix.protocol.reflect.cloning.SerializableCloner;
 import com.comphenix.protocol.reflect.fuzzy.FuzzyMethodContract;
 import com.comphenix.protocol.reflect.instances.DefaultInstances;
 import com.comphenix.protocol.utility.MinecraftMethods;
 import com.comphenix.protocol.utility.MinecraftReflection;
 import com.comphenix.protocol.utility.StreamSerializer;
 import com.comphenix.protocol.wrappers.*;
-import com.comphenix.protocol.wrappers.EnumWrappers.ChatType;
+import com.comphenix.protocol.wrappers.EnumWrappers.*;
-import com.comphenix.protocol.wrappers.EnumWrappers.ChatVisibility;
-import com.comphenix.protocol.wrappers.EnumWrappers.ClientCommand;
-import com.comphenix.protocol.wrappers.EnumWrappers.CombatEventType;
-import com.comphenix.protocol.wrappers.EnumWrappers.Difficulty;
-import com.comphenix.protocol.wrappers.EnumWrappers.Direction;
-import com.comphenix.protocol.wrappers.EnumWrappers.EntityUseAction;
-import com.comphenix.protocol.wrappers.EnumWrappers.EnumConverter;
-import com.comphenix.protocol.wrappers.EnumWrappers.Hand;
-import com.comphenix.protocol.wrappers.EnumWrappers.ItemSlot;
-import com.comphenix.protocol.wrappers.EnumWrappers.NativeGameMode;
-import com.comphenix.protocol.wrappers.EnumWrappers.Particle;
-import com.comphenix.protocol.wrappers.EnumWrappers.PlayerAction;
-import com.comphenix.protocol.wrappers.EnumWrappers.PlayerDigType;
-import com.comphenix.protocol.wrappers.EnumWrappers.PlayerInfoAction;
-import com.comphenix.protocol.wrappers.EnumWrappers.ResourcePackStatus;
-import com.comphenix.protocol.wrappers.EnumWrappers.ScoreboardAction;
-import com.comphenix.protocol.wrappers.EnumWrappers.SoundCategory;
-import com.comphenix.protocol.wrappers.EnumWrappers.TitleAction;
-import com.comphenix.protocol.wrappers.EnumWrappers.WorldBorderAction;
 import com.comphenix.protocol.wrappers.nbt.NbtBase;
 import com.comphenix.protocol.wrappers.nbt.NbtCompound;
 import com.comphenix.protocol.wrappers.nbt.NbtFactory;
@@ -101,6 +53,15 @@ import com.google.common.collect.Sets;
 import io.netty.buffer.ByteBuf;
 import io.netty.buffer.UnpooledByteBufAllocator;
 
+import org.bukkit.Material;
+import org.bukkit.Sound;
+import org.bukkit.World;
+import org.bukkit.WorldType;
+import org.bukkit.entity.Entity;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.potion.PotionEffectType;
+import org.bukkit.util.Vector;
+
 /**
  * Represents a Minecraft packet indirectly.
  * 
@@ -1201,21 +1162,52 @@ public class PacketContainer implements Serializable {
 	}
 
 	// ---- Metadata
-	// This map will only be initialized if it is actually used
+
-	private Map<String, Object> metadata;
+	/**
+	 * Gets the metadata value for a given key if it exists. Packet metadata expires after a minute, which is far longer
+	 * than a packet will ever be held in processing.
+	 *
+	 * @param key Metadata key
+	 * @param <T> Metadata type
+	 * @return The metadata value, or an empty optional
+	 */
+	public <T> Optional<T> getMeta(String key) {
+		return PacketMetadata.get(handle, key);
+	}
+
+	/**
+	 * Sets the metadata value at a given key. Packet metadata expires after a minute, which is far longer than a packet
+	 * will ever be held in processing.
+	 *
+	 * @param key Metadata key
+	 * @param value Metadata value
+	 * @param <T> Metadata type
+	 */
+	public <T> void setMeta(String key, T value) {
+		PacketMetadata.set(handle, key, value);
+	}
+
+	/**
+	 * Removes the metadata for a given key if it exists.
+	 * @param key Key to remove meta for
+	 */
+	public void removeMeta(String key) {
+		PacketMetadata.remove(handle, key);
+	}
+
+	// ---- Old Metadata API
+	// Scheduled for removal in 4.5
 
 	/**
 	 * Gets the metadata value for a given key.
 	 * 
 	 * @param key Metadata key
 	 * @return Metadata value, or null if nonexistent.
+	 * @deprecated Replaced with {@link #getMeta(String)}
 	 */
+	@Deprecated
 	public Object getMetadata(String key) {
-		if (metadata != null) {
+		return getMeta(key).orElse(null);
-			return metadata.get(key);
-		}
-
-		return null;
 	}
 
 	/**
@@ -1225,13 +1217,11 @@ public class PacketContainer implements Serializable {
 	 * 
 	 * @param key Metadata key
 	 * @param value Metadata value
+	 * @deprecated Replaced by {@link #setMeta(String, Object)}
 	 */
+	@Deprecated
 	public void addMetadata(String key, Object value) {
-		if (metadata == null) {
+		setMeta(key, value);
-			metadata = new HashMap<>();
-		}
-
-		metadata.put(key, value);
 	}
 
 	/**
@@ -1241,18 +1231,11 @@ public class PacketContainer implements Serializable {
 	 * 
 	 * @param key Metadata key
 	 * @return The previous value, or null if nonexistant.
+	 * @deprecated Replaced by {@link #removeMeta(String)}. This one was pretty much just for naming consistency.
 	 */
+	@Deprecated
 	public Object removeMetadata(String key) {
-		if (metadata != null) {
+		return PacketMetadata.remove(handle, key).orElseGet(null);
-			Object value = metadata.remove(key);
-			if (metadata.isEmpty()) {
-				metadata = null;
-			}
-
-			return value;
-		}
-
-		return null;
 	}
 
 	/**
@@ -1260,9 +1243,11 @@ public class PacketContainer implements Serializable {
 	 * 
 	 * @param key Metadata key
 	 * @return True if this packet has metadata for the key, false if not.
+	 * @deprecated Replaced with {@code getMeta(key).isPresent()}
 	 */
+	@Deprecated
 	public boolean hasMetadata(String key) {
-		return metadata != null && metadata.containsKey(key);
+		return getMeta(key).isPresent();
 	}
 
 	/**

modules/API/src/main/java/com/comphenix/protocol/events/PacketMetadata.java

@@ -0,0 +1,143 @@
+/**
+ *  ProtocolLib - Bukkit server library that allows access to the Minecraft protocol.
+ *  Copyright (C) 2017 dmulloy2
+ *
+ *  This program is free software; you can redistribute it and/or modify it under the terms of the
+ *  GNU General Public License as published by the Free Software Foundation; either version 2 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along with this program;
+ *  if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ *  02111-1307 USA
+ */
+package com.comphenix.protocol.events;
+
+import java.util.*;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+
+import org.apache.commons.lang3.Validate;
+
+/**
+ * Stores and retrieves metadata for applicable packet objects.
+ * @author dmulloy2
+ */
+class PacketMetadata {
+
+	private static class MetaObject<T> {
+		private final String key;
+		private final T value;
+
+		private MetaObject(String key, T value) {
+			this.key = key;
+			this.value = value;
+		}
+
+		@Override
+		public int hashCode() {
+			return Objects.hash(key, value);
+		}
+
+		@Override
+		public boolean equals(Object o) {
+			if (o == this) return true;
+
+			if (o instanceof MetaObject) {
+				MetaObject that = (MetaObject) o;
+				return that.key.equals(this.key) &&
+			           that.value.equals(this.value);
+			}
+
+			return false;
+		}
+
+		@Override
+		public String toString() {
+			return "MetaObject[" + key + "=" + value + "]";
+		}
+	}
+
+	// Packet meta cache
+	private static Cache<Object, List<MetaObject>> META_CACHE;
+
+	public static <T> Optional<T> get(Object packet, String key) {
+		Validate.notNull(key, "Null keys are not permitted!");
+
+		if (META_CACHE == null) {
+			return Optional.empty();
+		}
+
+		List<MetaObject> meta = META_CACHE.getIfPresent(packet);
+		if (meta == null) {
+			return Optional.empty();
+		}
+
+		for (MetaObject object : meta) {
+			if (object.key.equals(key)) {
+				return Optional.of((T) object.value);
+			}
+		}
+
+		return Optional.empty();
+	}
+
+	private static void createCache() {
+		META_CACHE = CacheBuilder
+				.newBuilder()
+				.expireAfterWrite(1, TimeUnit.MINUTES)
+				.build();
+	}
+
+	public static <T> void set(Object packet, String key, T value) {
+		Validate.notNull(key, "Null keys are not permitted!");
+
+		if (META_CACHE == null) {
+			createCache();
+		}
+
+		List<MetaObject> packetMeta;
+
+		try {
+			packetMeta = META_CACHE.get(packet, ArrayList::new);
+		} catch (ExecutionException ex) {
+			// Not possible, but let's humor the array list constructor having an issue
+			packetMeta = new ArrayList<>();
+		}
+
+		packetMeta.removeIf(meta -> meta.key.equals(key));
+		packetMeta.add(new MetaObject<>(key, value));
+		META_CACHE.put(packet, packetMeta);
+	}
+
+	public static <T> Optional<T> remove(Object packet, String key) {
+		Validate.notNull(key, "Null keys are not permitted!");
+
+		if (META_CACHE == null) {
+			return Optional.empty();
+		}
+
+		List<MetaObject> packetMeta = META_CACHE.getIfPresent(packet);
+		if (packetMeta == null) {
+			return Optional.empty();
+		}
+
+		Optional<T> value = Optional.empty();
+		Iterator<MetaObject> iter = packetMeta.iterator();
+		while (iter.hasNext()) {
+			MetaObject meta = iter.next();
+			if (meta.key.equals(key)) {
+				value = Optional.of((T) meta.value);
+				iter.remove();
+			}
+		}
+
+		return value;
+	}
+}