SPIGOT-1714: Draft API for player list header / footer

By: md_5 <git@md-5.net>

paper-server/nms-patches/PacketPlayOutPlayerListHeaderFooter.patch

@@ -0,0 +1,13 @@
+--- a/net/minecraft/server/PacketPlayOutPlayerListHeaderFooter.java
++++ b/net/minecraft/server/PacketPlayOutPlayerListHeaderFooter.java
+@@ -4,8 +4,8 @@
+ 
+ public class PacketPlayOutPlayerListHeaderFooter implements Packet<PacketListenerPlayOut> {
+ 
+-    private IChatBaseComponent a;
+-    private IChatBaseComponent b;
++    public IChatBaseComponent a; // PAIL
++    public IChatBaseComponent b; // PAIL
+ 
+     public PacketPlayOutPlayerListHeaderFooter() {}
+ 

paper-server/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -31,6 +31,7 @@ import net.minecraft.server.AttributeMapServer;
 import net.minecraft.server.AttributeModifiable;
 import net.minecraft.server.AttributeRanged;
 import net.minecraft.server.BlockPosition;
+import net.minecraft.server.ChatComponentText;
 import net.minecraft.server.Container;
 import net.minecraft.server.Entity;
 import net.minecraft.server.EntityHuman;
@@ -52,6 +53,7 @@ import net.minecraft.server.PacketPlayOutCustomSoundEffect;
 import net.minecraft.server.PacketPlayOutMap;
 import net.minecraft.server.PacketPlayOutNamedSoundEffect;
 import net.minecraft.server.PacketPlayOutPlayerInfo;
+import net.minecraft.server.PacketPlayOutPlayerListHeaderFooter;
 import net.minecraft.server.PacketPlayOutSpawnPosition;
 import net.minecraft.server.PacketPlayOutStopSound;
 import net.minecraft.server.PacketPlayOutTitle;
@@ -228,6 +230,47 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         }
     }
 
+    private IChatBaseComponent playerListHeader;
+    private IChatBaseComponent playerListFooter;
+
+    @Override
+    public String getPlayerListHeader() {
+        return (playerListHeader == null) ? null : CraftChatMessage.fromComponent(playerListHeader);
+    }
+
+    @Override
+    public String getPlayerListFooter() {
+        return (playerListFooter == null) ? null : CraftChatMessage.fromComponent(playerListFooter);
+    }
+
+    @Override
+    public void setPlayerListHeader(String header) {
+        this.playerListHeader = CraftChatMessage.fromStringOrNull(header);
+        updatePlayerListHeaderFooter();
+    }
+
+    @Override
+    public void setPlayerListFooter(String footer) {
+        this.playerListFooter = CraftChatMessage.fromStringOrNull(footer);
+        updatePlayerListHeaderFooter();
+    }
+
+    @Override
+    public void setPlayerListHeaderFooter(String header, String footer) {
+        this.playerListHeader = CraftChatMessage.fromStringOrNull(header);
+        this.playerListFooter = CraftChatMessage.fromStringOrNull(footer);
+        updatePlayerListHeaderFooter();
+    }
+
+    private void updatePlayerListHeaderFooter() {
+        if (getHandle().playerConnection == null) return;
+
+        PacketPlayOutPlayerListHeaderFooter packet = new PacketPlayOutPlayerListHeaderFooter();
+        packet.a = (this.playerListHeader == null) ? new ChatComponentText("") : this.playerListHeader;
+        packet.b = (this.playerListFooter == null) ? new ChatComponentText("") : this.playerListFooter;
+        getHandle().playerConnection.sendPacket(packet);
+    }
+
     @Override
     public boolean equals(Object obj) {
         if (!(obj instanceof OfflinePlayer)) {