Чат и список игроков

- Протокол: Chat (что сказал сервер), ChatSend (что сказал клиент) и PlayerList
  (весь список игроков с их режимами).
- Сервер: сообщения уходят всем, а имя отправителя ставит сервер, поэтому подделать
  его нельзя. Список игроков уходит всем целиком, когда он меняется. Команды
  сервера: /help и /players.
- Клиент: перевод наших пакетов в игровые (SPacketChat и SPacketPlayerListItem),
  уходящий чат перехватывается патчем, список игроков обновляется по разнице
  (ушедших убираем, пришедших добавляем).
- Тесты: два игрока, один пишет - второй слышит с правильным именем; список
  игроков приходит обоим и меняется, когда кто-то выходит.

Попутно: run-server.ps1 теперь знает про rsx-plugin-api, иначе сервер не
запускался (нет класса Hitboxes в classpath).

Тесты: протокол 34, сервер 87. Форк собирается чисто.

rsx-protocol/src/main/java/net/rustnotmc/protocol/Packets.java

@@ -161,6 +161,15 @@ public final class Packets {
     /** The client hits something. */
     public static final int ATTACK = 0x2D;
 
+    /** What somebody said. */
+    public static final int CHAT = 0x2E;
+
+    /** The client says something. */
+    public static final int CHAT_SEND = 0x2F;
+
+    /** Who is in the world. */
+    public static final int PLAYER_LIST = 0x30;
+
     /**
      * One slot of the inventory and what is in it now.
      *
@@ -1604,6 +1613,100 @@ public final class Packets {
         }
     }
 
+    /**
+     * What somebody said.
+     *
+     * The name of the sender is here, because the server is the one who
+     * decides who said what: a client cannot claim to be somebody else.
+     */
+    public static final class Chat implements Packet {
+
+        /** The name of the sender, or empty when the server speaks. */
+        public final String from;
+
+        public final String text;
+
+        public Chat(String from, String text) {
+            this.from = from == null ? "" : from;
+            this.text = text == null ? "" : text;
+        }
+
+        public Buf write() {
+            Buf buf = new Buf(64 + this.text.length());
+            buf.writeString(this.from);
+            buf.writeString(this.text);
+            return buf;
+        }
+
+        public static Chat read(Buf in) {
+            return new Chat(in.readString(MAX_TEXT), in.readString(MAX_TEXT));
+        }
+    }
+
+    /** The client says something. */
+    public static final class ChatSend implements Packet {
+
+        public final String text;
+
+        public ChatSend(String text) {
+            this.text = text == null ? "" : text;
+        }
+
+        public Buf write() {
+            Buf buf = new Buf(64 + this.text.length());
+            buf.writeString(this.text);
+            return buf;
+        }
+
+        public static ChatSend read(Buf in) {
+            return new ChatSend(in.readString(MAX_TEXT));
+        }
+    }
+
+    /**
+     * Who is in the world.
+     *
+     * The whole list, every time it changes: the list of a server with a
+     * handful of players is small, and a full list cannot get out of step
+     * with itself the way a difference can.
+     */
+    public static final class PlayerList implements Packet {
+
+        public final String[] names;
+
+        /** The game mode of each player, in the same order. */
+        public final int[] gameModes;
+
+        public PlayerList(String[] names, int[] gameModes) {
+            this.names = names;
+            this.gameModes = gameModes;
+        }
+
+        public Buf write() {
+            Buf buf = new Buf(32 + this.names.length * 24);
+            buf.writeVarInt(this.names.length);
+            for (int i = 0; i < this.names.length; i++) {
+                buf.writeString(this.names[i]);
+                buf.writeVarInt(i < this.gameModes.length ? this.gameModes[i] : 0);
+            }
+            return buf;
+        }
+
+        public static PlayerList read(Buf in) {
+            int count = in.readVarInt();
+            if (count < 0 || count > 4096) {
+                throw new ProtocolException("that many players is not real");
+            }
+            String[] names = new String[count];
+            int[] gameModes = new int[count];
+            for (int i = 0; i < count; i++) {
+                names[i] = in.readString(MAX_TEXT);
+                gameModes[i] = in.readVarInt();
+            }
+            return new PlayerList(names, gameModes);
+        }
+    }
+
     /**
      * Every packet id this build knows, and what it decodes into.
      *
@@ -1648,6 +1751,9 @@ public final class Packets {
         map.put(Integer.valueOf(HITBOX_INSTANCES), "HitboxInstances");
         map.put(Integer.valueOf(HITBOXES_RELOAD), "HitboxesReload");
         map.put(Integer.valueOf(ATTACK), "Attack");
+        map.put(Integer.valueOf(CHAT), "Chat");
+        map.put(Integer.valueOf(CHAT_SEND), "ChatSend");
+        map.put(Integer.valueOf(PLAYER_LIST), "PlayerList");
         map.put(Integer.valueOf(DISCONNECT), "Disconnect");
         return map;
     }

rsx-protocol/src/test/java/net/rustnotmc/protocol/ItemTest.java

@@ -326,6 +326,23 @@ public final class ItemTest {
         near("the place of the hit survives", 2.5, attackBack.y);
         eq("the hand survives", Integer.valueOf(Packets.Attack.HAND_MAIN),
                 Integer.valueOf(attackBack.hand));
+
+        Packets.Chat chat = new Packets.Chat("Player", "hello there");
+        Packets.Chat chatBack = Packets.Chat.read(new Buf(chat.write().toByteArray()));
+        eq("the sender survives", "Player", chatBack.from);
+        eq("the line survives", "hello there", chatBack.text);
+
+        Packets.ChatSend send = new Packets.ChatSend("hi");
+        Packets.ChatSend sendBack = Packets.ChatSend.read(new Buf(send.write().toByteArray()));
+        eq("the sent line survives", "hi", sendBack.text);
+
+        Packets.PlayerList list = new Packets.PlayerList(
+                new String[]{"One", "Two"}, new int[]{0, 1});
+        Packets.PlayerList listBack =
+                Packets.PlayerList.read(new Buf(list.write().toByteArray()));
+        eq("two names", Integer.valueOf(2), Integer.valueOf(listBack.names.length));
+        eq("the first name", "One", listBack.names[0]);
+        eq("the second mode", Integer.valueOf(1), Integer.valueOf(listBack.gameModes[1]));
     }
 
     private static void near(Object what, double expected, double actual) {

rsx-protocol/src/test/java/net/rustnotmc/protocol/ProtocolTest.java

@@ -552,7 +552,7 @@ public final class ProtocolTest {
                 Packets.CONTAINER_OPEN, Packets.CONTAINER_TAKE,
                 Packets.LEARN_BLUEPRINT,
                 Packets.HITBOXES, Packets.HITBOX_INSTANCES, Packets.HITBOXES_RELOAD,
-                Packets.ATTACK,
+                Packets.ATTACK, Packets.CHAT, Packets.CHAT_SEND, Packets.PLAYER_LIST,
                 Packets.DISCONNECT,
         };
         for (int i = 0; i < ids.length; i++) {