/**
* Copyright (c) 2011-2015, SpaceToad and the BuildCraft Team
* http://www.mod-buildcraft.com
* <p/>
* BuildCraft is distributed under the terms of the Minecraft Mod Public
* License 1.0, or MMPL. Please check the contents of the license located in
* http://www.mod-buildcraft.com/MMPL-1.0.txt
*/
package buildcraft.core.lib.network;
import java.lang.ref.WeakReference;
import java.util.List;
import org.apache.logging.log4j.Level;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.MessageToMessageCodec;
import io.netty.util.AttributeKey;
import gnu.trove.map.hash.TByteObjectHashMap;
import gnu.trove.map.hash.TObjectByteHashMap;
import cpw.mods.fml.common.FMLLog;
import cpw.mods.fml.common.network.NetworkRegistry;
import cpw.mods.fml.common.network.internal.FMLProxyPacket;
import buildcraft.core.lib.network.command.PacketCommand;
/**
* Code based on FMLIndexedMessageToMessageCodec, but since some of its fields
* are private, I needed a custom version.
*/
@io.netty.channel.ChannelHandler.Sharable
public final class ChannelHandler extends MessageToMessageCodec<FMLProxyPacket, Packet> {
public static final AttributeKey<ThreadLocal<WeakReference<FMLProxyPacket>>> INBOUNDPACKETTRACKER = new AttributeKey<ThreadLocal<WeakReference<FMLProxyPacket>>>("bc:inboundpacket");
private TByteObjectHashMap<Class<? extends Packet>> discriminators = new TByteObjectHashMap<Class<? extends Packet>>();
private TObjectByteHashMap<Class<? extends Packet>> types = new TObjectByteHashMap<Class<? extends Packet>>();
private int maxDiscriminator;
public ChannelHandler() {
// Packets common to buildcraft.core.network
addDiscriminator(0, PacketTileUpdate.class);
addDiscriminator(1, PacketTileState.class);
addDiscriminator(2, PacketNBT.class);
addDiscriminator(3, PacketSlotChange.class);
addDiscriminator(4, PacketGuiReturn.class);
addDiscriminator(5, PacketGuiWidget.class);
addDiscriminator(6, PacketUpdate.class);
addDiscriminator(7, PacketCommand.class);
addDiscriminator(8, PacketEntityUpdate.class);
maxDiscriminator = 9;
}
public byte getDiscriminator(Class<? extends Packet> clazz) {
return types.get(clazz);
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
super.handlerAdded(ctx);
ctx.attr(INBOUNDPACKETTRACKER).set(new ThreadLocal<WeakReference<FMLProxyPacket>>());
}
public ChannelHandler addDiscriminator(int discriminator, Class<? extends Packet> type) {
discriminators.put((byte) discriminator, type);
types.put(type, (byte) discriminator);
return this;
}
@Override
protected void encode(ChannelHandlerContext ctx, Packet msg, List<Object> out) throws Exception {
ByteBuf buffer = Unpooled.buffer();
Class<? extends Packet> clazz = msg.getClass();
byte discriminator = types.get(clazz);
buffer.writeByte(discriminator);
msg.writeData(buffer);
FMLProxyPacket proxy = new FMLProxyPacket(buffer.copy(), ctx.channel().attr(NetworkRegistry.FML_CHANNEL).get());
WeakReference<FMLProxyPacket> ref = ctx.attr(INBOUNDPACKETTRACKER).get().get();
FMLProxyPacket old = ref == null ? null : ref.get();
if (old != null) {
proxy.setDispatcher(old.getDispatcher());
}
out.add(proxy);
}
@Override
protected void decode(ChannelHandlerContext ctx, FMLProxyPacket msg, List<Object> out) throws Exception {
testMessageValidity(msg);
ByteBuf payload = msg.payload();
byte discriminator = payload.readByte();
Class<? extends Packet> clazz = discriminators.get(discriminator);
if (clazz == null) {
throw new NullPointerException("Undefined message for discriminator " + discriminator + " in channel " + msg.channel());
}
Packet newMsg = clazz.newInstance();
ctx.attr(INBOUNDPACKETTRACKER).get().set(new WeakReference<FMLProxyPacket>(msg));
newMsg.readData(payload.slice());
out.add(newMsg);
}
/**
* Called to verify the message received. This can be used to hard disconnect in case of an unexpected packet,
* say due to a weird protocol mismatch. Use with caution.
* @param msg
*/
protected void testMessageValidity(FMLProxyPacket msg) {
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
FMLLog.log(Level.ERROR, cause, "BC ChannelHandler exception caught");
super.exceptionCaught(ctx, cause);
}
public void registerPacketType(Class<? extends Packet> packetType) {
addDiscriminator(maxDiscriminator++, packetType);
}
}