Add conversion methods to WirePacket

modules/API/src/main/java/com/comphenix/protocol/injector/netty/WirePacket.java

@@ -16,30 +16,71 @@
  */
 package com.comphenix.protocol.injector.netty;
 
+import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import java.lang.reflect.Method;
+
+import com.comphenix.protocol.PacketType;
+import com.comphenix.protocol.events.PacketContainer;
+import com.comphenix.protocol.utility.MinecraftMethods;
+import com.comphenix.protocol.utility.MinecraftReflection;
+
 import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
 
 /**
+ * A packet represented only by its id and bytes.
  * @author dmulloy2
  */
-
 public class WirePacket {
 	private final int id;
 	private final byte[] bytes;
 
+	/**
+	 * Constructs a new WirePacket with a given type and contents
+	 * @param type Type of the packet
+	 * @param bytes Contents of the packet
+	 */
+	public WirePacket(PacketType type, byte[] bytes) {
+		this.id = checkNotNull(type, "type cannot be null").getCurrentId();
+		this.bytes = bytes;
+	}
+
+	/**
+	 * Constructs a new WirePacket with a given id and contents
+	 * @param id ID of the packet
+	 * @param bytes Contents of the packet
+	 */
 	public WirePacket(int id, byte[] bytes) {
 		this.id = id;
 		this.bytes = bytes;
 	}
 
+	/**
+	 * Gets this packet's ID
+	 * @return The ID
+	 */
 	public int getId() {
 		return id;
 	}
 
+	/**
+	 * Gets this packet's contents as a byte array
+	 * @return The contents
+	 */
 	public byte[] getBytes() {
 		return bytes;
 	}
 
+	/**
+	 * Writes the id of this packet to a given output
+	 * @param output Output to write to
+	 */
 	public void writeId(ByteBuf output) {
+		checkNotNull(output, "output cannot be null!");
+		// From PacketDataSerializer#d(int)
+
 		int i = id;
 		while ((i & -128) != 0) {
 			output.writeByte(i & 127 | 128);
@@ -49,7 +90,78 @@ public class WirePacket {
 		output.writeByte(i);
 	}
 
+	/**
+	 * Writes the contents of this packet to a given output
+	 * @param output Output to write to
+	 */
 	public void writeBytes(ByteBuf output) {
+		checkNotNull(output, "output cannot be null!");
 		output.writeBytes(bytes);
 	}
+
+	/**
+	 * Fully writes the ID and contents of this packet to a given output
+	 * @param output Output to write to
+	 */
+	public void writeFully(ByteBuf output) {
+		writeId(output);
+		writeBytes(output);
+	}
+
+	/**
+	 * Serializes this packet into a byte buffer
+	 * @return The buffer
+	 */
+	public ByteBuf serialize() {
+		ByteBuf buffer = Unpooled.buffer();
+		writeFully(buffer);
+		return buffer;
+	}
+
+	/**
+	 * Creates a WirePacket from an existing PacketContainer
+	 * @param packet Existing packet
+	 * @return The resulting WirePacket
+	 */
+	public static WirePacket fromPacket(PacketContainer packet) {
+		checkNotNull(packet, "packet cannot be null!");
+
+		int id = packet.getType().getCurrentId();
+
+		ByteBuf buffer = PacketContainer.createPacketBuffer();
+		Method write = MinecraftMethods.getPacketWriteByteBufMethod();
+
+		try {
+			write.invoke(packet.getHandle(), buffer);
+		} catch (ReflectiveOperationException ex) {
+			throw new RuntimeException("Failed to serialize packet contents.", ex);
+		}
+
+		return new WirePacket(id, buffer.array());
+	}
+
+	/**
+	 * Creates a WirePacket from an existing Minecraft packet
+	 * @param packet Existing Minecraft packet
+	 * @return The resulting WirePacket
+	 * @throws IllegalArgumentException If the packet is null or not a Minecraft packet
+	 */
+	public static WirePacket fromPacket(Object packet) {
+		checkNotNull(packet, "packet cannot be null!");
+		checkArgument(MinecraftReflection.isPacketClass(packet), "packet must be a Minecraft packet");
+
+		PacketType type = PacketType.fromClass(packet.getClass());
+		int id = type.getCurrentId();
+
+		ByteBuf buffer = PacketContainer.createPacketBuffer();
+		Method write = MinecraftMethods.getPacketWriteByteBufMethod();
+
+		try {
+			write.invoke(packet, buffer);
+		} catch (ReflectiveOperationException ex) {
+			throw new RuntimeException("Failed to serialize packet contents.", ex);
+		}
+
+		return new WirePacket(id, buffer.array());
+	}
 }