Title API (#95)

api/src/main/java/com/velocitypowered/api/proxy/Player.java

@@ -6,6 +6,7 @@ import com.velocitypowered.api.proxy.messages.ChannelMessageSource;
 import com.velocitypowered.api.proxy.player.PlayerSettings;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.api.util.MessagePosition;
+import com.velocitypowered.api.util.title.Title;
 import net.kyori.text.Component;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
@@ -83,6 +84,12 @@ public interface Player extends CommandSource, InboundConnection, ChannelMessage
      */
     void disconnect(Component reason);
 
+    /**
+     * Sends the specified title to the client.
+     * @param title the title to send
+     */
+    void sendTitle(Title title);
+
     /**
      * Sends chat input onto the players current server as if they typed it
      * into the client chat box.

api/src/main/java/com/velocitypowered/api/util/title/TextTitle.java

@@ -0,0 +1,236 @@
+package com.velocitypowered.api.util.title;
+
+import com.google.common.base.Preconditions;
+import net.kyori.text.Component;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+import java.util.Objects;
+import java.util.Optional;
+
+/**
+ * Represents a "full" title, including all components. This class is immutable.
+ */
+public class TextTitle implements Title {
+    private final Component title;
+    private final Component subtitle;
+    private final int stay;
+    private final int fadeIn;
+    private final int fadeOut;
+    private final boolean resetBeforeSend;
+
+    private TextTitle(Builder builder) {
+        this.title = builder.title;
+        this.subtitle = builder.subtitle;
+        this.stay = builder.stay;
+        this.fadeIn = builder.fadeIn;
+        this.fadeOut = builder.fadeOut;
+        this.resetBeforeSend = builder.resetBeforeSend;
+    }
+
+    /**
+     * Returns the main title this title has, if any.
+     * @return the main title of this title
+     */
+    public Optional<Component> getTitle() {
+        return Optional.ofNullable(title);
+    }
+
+    /**
+     * Returns the subtitle this title has, if any.
+     * @return the subtitle
+     */
+    public Optional<Component> getSubtitle() {
+        return Optional.ofNullable(subtitle);
+    }
+
+    /**
+     * Returns the number of ticks this title will stay up.
+     * @return how long the title will stay, in ticks
+     */
+    public int getStay() {
+        return stay;
+    }
+
+    /**
+     * Returns the number of ticks over which this title will fade in.
+     * @return how long the title will fade in, in ticks
+     */
+    public int getFadeIn() {
+        return fadeIn;
+    }
+
+    /**
+     * Returns the number of ticks over which this title will fade out.
+     * @return how long the title will fade out, in ticks
+     */
+    public int getFadeOut() {
+        return fadeOut;
+    }
+
+    /**
+     * Returns whether or not a reset packet will be sent before this title is sent. By default, unless explicitly
+     * disabled, this is enabled by default.
+     * @return whether or not a reset packet will be sent before this title is sent
+     */
+    public boolean isResetBeforeSend() {
+        return resetBeforeSend;
+    }
+
+    /**
+     * Determines whether or not this title has times set on it. If none are set, it will update the previous title
+     * set on the client.
+     * @return whether or not this title has times set on it
+     */
+    public boolean areTimesSet() {
+        return stay != 0 || fadeIn != 0 || fadeOut != 0;
+    }
+
+    /**
+     * Creates a new builder from the contents of this title so that it may be changed.
+     * @return a builder instance with the contents of this title
+     */
+    public Builder toBuilder() {
+        return new Builder(this);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        TextTitle textTitle = (TextTitle) o;
+        return stay == textTitle.stay &&
+                fadeIn == textTitle.fadeIn &&
+                fadeOut == textTitle.fadeOut &&
+                resetBeforeSend == textTitle.resetBeforeSend &&
+                Objects.equals(title, textTitle.title) &&
+                Objects.equals(subtitle, textTitle.subtitle);
+    }
+
+    @Override
+    public String toString() {
+        return "TextTitle{" +
+                "title=" + title +
+                ", subtitle=" + subtitle +
+                ", stay=" + stay +
+                ", fadeIn=" + fadeIn +
+                ", fadeOut=" + fadeOut +
+                ", resetBeforeSend=" + resetBeforeSend +
+                '}';
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(title, subtitle, stay, fadeIn, fadeOut, resetBeforeSend);
+    }
+
+    /**
+     * Creates a new builder for constructing titles.
+     * @return a builder for constructing titles
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static class Builder {
+        private @Nullable Component title;
+        private @Nullable Component subtitle;
+        private int stay;
+        private int fadeIn;
+        private int fadeOut;
+        private boolean resetBeforeSend = true;
+
+        private Builder() {}
+
+        private Builder(TextTitle copy) {
+            this.title = copy.title;
+            this.subtitle = copy.subtitle;
+            this.stay = copy.stay;
+            this.fadeIn = copy.fadeIn;
+            this.fadeOut = copy.fadeOut;
+            this.resetBeforeSend = copy.resetBeforeSend;
+        }
+
+        public Builder title(Component title) {
+            this.title = Preconditions.checkNotNull(title, "title");
+            return this;
+        }
+
+        public Builder clearTitle() {
+            this.title = null;
+            return this;
+        }
+
+        public Builder subtitle(Component subtitle) {
+            this.subtitle = Preconditions.checkNotNull(subtitle, "subtitle");
+            return this;
+        }
+
+        public Builder clearSubtitle() {
+            this.subtitle = null;
+            return this;
+        }
+
+        public Builder stay(int ticks) {
+            Preconditions.checkArgument(ticks >= 0, "ticks value %s is negative", ticks);
+            this.stay = ticks;
+            return this;
+        }
+
+        public Builder fadeIn(int ticks) {
+            Preconditions.checkArgument(ticks >= 0, "ticks value %s is negative", ticks);
+            this.fadeIn = ticks;
+            return this;
+        }
+
+        public Builder fadeOut(int ticks) {
+            Preconditions.checkArgument(ticks >= 0, "ticks value %s is negative", ticks);
+            this.fadeOut = ticks;
+            return this;
+        }
+
+        public Builder resetBeforeSend(boolean b) {
+            this.resetBeforeSend = b;
+            return this;
+        }
+
+        public Component getTitle() {
+            return title;
+        }
+
+        public Component getSubtitle() {
+            return subtitle;
+        }
+
+        public int getStay() {
+            return stay;
+        }
+
+        public int getFadeIn() {
+            return fadeIn;
+        }
+
+        public int getFadeOut() {
+            return fadeOut;
+        }
+
+        public boolean isResetBeforeSend() {
+            return resetBeforeSend;
+        }
+
+        public TextTitle build() {
+            return new TextTitle(this);
+        }
+
+        @Override
+        public String toString() {
+            return "Builder{" +
+                    "title=" + title +
+                    ", subtitle=" + subtitle +
+                    ", stay=" + stay +
+                    ", fadeIn=" + fadeIn +
+                    ", fadeOut=" + fadeOut +
+                    ", resetBeforeSend=" + resetBeforeSend +
+                    '}';
+        }
+    }
+}

api/src/main/java/com/velocitypowered/api/util/title/Title.java

@@ -0,0 +1,7 @@
+package com.velocitypowered.api.util.title;
+
+/**
+ * Represents a title that can be sent to a Minecraft client.
+ */
+public interface Title {
+}

api/src/main/java/com/velocitypowered/api/util/title/Titles.java

@@ -0,0 +1,50 @@
+package com.velocitypowered.api.util.title;
+
+/**
+ * Provides special-purpose titles.
+ */
+public class Titles {
+    private Titles() {
+        throw new AssertionError();
+    }
+
+    private static final Title RESET = new Title() {
+        @Override
+        public String toString() {
+            return "reset title";
+        }
+    };
+
+    private static final Title HIDE = new Title() {
+        @Override
+        public String toString() {
+            return "hide title";
+        }
+    };
+
+    /**
+     * Returns a title that, when sent to the client, will cause all title data to be reset and any existing title to be
+     * hidden.
+     * @return the reset title
+     */
+    public static Title reset() {
+        return RESET;
+    }
+
+    /**
+     * Returns a title that, when sent to the client, will cause any existing title to be hidden. The title may be
+     * restored by a {@link TextTitle} with no title or subtitle (only a time).
+     * @return the hide title
+     */
+    public static Title hide() {
+        return HIDE;
+    }
+
+    /**
+     * Returns a builder for {@link TextTitle}s.
+     * @return a builder for text titles
+     */
+    public static TextTitle.Builder text() {
+        return TextTitle.builder();
+    }
+}

api/src/main/java/com/velocitypowered/api/util/title/package-info.java

@@ -0,0 +1,4 @@
+/**
+ * Provides data structures for creating and manipulating titles.
+ */
+package com.velocitypowered.api.util.title;

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ClientPlaySessionHandler.java

@@ -219,6 +219,9 @@ public class ClientPlaySessionHandler implements MinecraftSessionHandler {
             player.getConnectedServer().getMinecraftConnection().delayedWrite(pm);
         }
 
+        // Clear any title from the previous server.
+        player.getConnection().delayedWrite(TitlePacket.resetForProtocolVersion(player.getProtocolVersion()));
+
         // Flush everything
         player.getConnection().flush();
         player.getConnectedServer().getMinecraftConnection().flush();

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -15,6 +15,9 @@ import com.velocitypowered.api.proxy.player.PlayerSettings;
 import com.velocitypowered.api.proxy.server.RegisteredServer;
 import com.velocitypowered.api.util.GameProfile;
 import com.velocitypowered.api.util.MessagePosition;
+import com.velocitypowered.api.util.title.TextTitle;
+import com.velocitypowered.api.util.title.Title;
+import com.velocitypowered.api.util.title.Titles;
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
 import com.velocitypowered.proxy.connection.MinecraftConnectionAssociation;
@@ -22,6 +25,7 @@ import com.velocitypowered.proxy.connection.VelocityConstants;
 import com.velocitypowered.proxy.connection.backend.VelocityServerConnection;
 import com.velocitypowered.proxy.connection.util.ConnectionMessages;
 import com.velocitypowered.proxy.connection.util.ConnectionRequestResults;
+import com.velocitypowered.proxy.protocol.ProtocolConstants;
 import com.velocitypowered.proxy.protocol.packet.*;
 import com.velocitypowered.proxy.server.VelocityRegisteredServer;
 import com.velocitypowered.proxy.util.ThrowableUtils;
@@ -139,11 +143,20 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         byte pos = (byte) position.ordinal();
         String json;
         if (position == MessagePosition.ACTION_BAR) {
-            // Due to issues with action bar packets, we'll need to convert the text message into a legacy message
-            // and then inject the legacy text into a component... yuck!
-            JsonObject object = new JsonObject();
-            object.addProperty("text", ComponentSerializers.LEGACY.serialize(component));
-            json = VelocityServer.GSON.toJson(object);
+            if (getProtocolVersion() >= ProtocolConstants.MINECRAFT_1_11) {
+                // We can use the title packet instead.
+                TitlePacket pkt = new TitlePacket();
+                pkt.setAction(TitlePacket.SET_ACTION_BAR);
+                pkt.setComponent(ComponentSerializers.JSON.serialize(component));
+                connection.write(pkt);
+                return;
+            } else {
+                // Due to issues with action bar packets, we'll need to convert the text message into a legacy message
+                // and then inject the legacy text into a component... yuck!
+                JsonObject object = new JsonObject();
+                object.addProperty("text", ComponentSerializers.LEGACY.serialize(component));
+                json = VelocityServer.GSON.toJson(object);
+            }
         } else {
             json = ComponentSerializers.JSON.serialize(component);
         }
@@ -176,6 +189,48 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
         connection.closeWith(Disconnect.create(reason));
     }
 
+    @Override
+    public void sendTitle(Title title) {
+        Preconditions.checkNotNull(title, "title");
+
+        if (title.equals(Titles.reset())) {
+            connection.write(TitlePacket.resetForProtocolVersion(connection.getProtocolVersion()));
+        } else if (title.equals(Titles.hide())) {
+            connection.write(TitlePacket.hideForProtocolVersion(connection.getProtocolVersion()));
+        } else if (title instanceof TextTitle) {
+            TextTitle tt = (TextTitle) title;
+
+            if (tt.isResetBeforeSend()) {
+                connection.delayedWrite(TitlePacket.resetForProtocolVersion(connection.getProtocolVersion()));
+            }
+
+            if (tt.getTitle().isPresent()) {
+                TitlePacket titlePkt = new TitlePacket();
+                titlePkt.setAction(TitlePacket.SET_TITLE);
+                titlePkt.setComponent(ComponentSerializers.JSON.serialize(tt.getTitle().get()));
+                connection.delayedWrite(titlePkt);
+            }
+            if (tt.getSubtitle().isPresent()) {
+                TitlePacket titlePkt = new TitlePacket();
+                titlePkt.setAction(TitlePacket.SET_SUBTITLE);
+                titlePkt.setComponent(ComponentSerializers.JSON.serialize(tt.getSubtitle().get()));
+                connection.delayedWrite(titlePkt);
+            }
+
+            if (tt.areTimesSet()) {
+                TitlePacket timesPkt = TitlePacket.timesForProtocolVersion(connection.getProtocolVersion());
+                timesPkt.setFadeIn(tt.getFadeIn());
+                timesPkt.setStay(tt.getStay());
+                timesPkt.setFadeOut(tt.getFadeOut());
+                connection.delayedWrite(timesPkt);
+            }
+            connection.flush();
+        } else {
+            throw new IllegalArgumentException("Unknown title class " + title.getClass().getName());
+        }
+
+    }
+
     public VelocityServerConnection getConnectedServer() {
         return connectedServer;
     }

proxy/src/main/java/com/velocitypowered/proxy/protocol/StateRegistry.java

@@ -136,6 +136,12 @@ public enum StateRegistry {
                     map(0x44, MINECRAFT_1_12, true),
                     map(0x45, MINECRAFT_1_12_1, true),
                     map(0x48, MINECRAFT_1_13, true));
+            CLIENTBOUND.register(TitlePacket.class, TitlePacket::new,
+                    map(0x45, MINECRAFT_1_8, true),
+                    map(0x45, MINECRAFT_1_9, true),
+                    map(0x47, MINECRAFT_1_12, true),
+                    map(0x48, MINECRAFT_1_12_1, true),
+                    map(0x4B, MINECRAFT_1_13, true));
         }
     },
     LOGIN {

proxy/src/main/java/com/velocitypowered/proxy/protocol/packet/TitlePacket.java

@@ -0,0 +1,137 @@
+package com.velocitypowered.proxy.protocol.packet;
+
+import com.google.common.base.Preconditions;
+import com.velocitypowered.proxy.protocol.MinecraftPacket;
+import com.velocitypowered.proxy.protocol.ProtocolConstants;
+import com.velocitypowered.proxy.protocol.ProtocolUtils;
+import io.netty.buffer.ByteBuf;
+
+public class TitlePacket implements MinecraftPacket {
+    public static final int SET_TITLE = 0;
+    public static final int SET_SUBTITLE = 1;
+    public static final int SET_ACTION_BAR = 2;
+    public static final int SET_TIMES = 3;
+    public static final int SET_TIMES_OLD = 2;
+    public static final int HIDE = 4;
+    public static final int HIDE_OLD = 3;
+    public static final int RESET = 5;
+    public static final int RESET_OLD = 4;
+
+    private int action;
+    private String component;
+    private int fadeIn;
+    private int stay;
+    private int fadeOut;
+
+    @Override
+    public void decode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        throw new UnsupportedOperationException(); // encode only
+    }
+
+    @Override
+    public void encode(ByteBuf buf, ProtocolConstants.Direction direction, int protocolVersion) {
+        ProtocolUtils.writeVarInt(buf, action);
+        if (protocolVersion >= ProtocolConstants.MINECRAFT_1_11) {
+            // 1.11+ shifted the action enum by 1 to handle the action bar
+            switch (action) {
+                case SET_TITLE:
+                case SET_SUBTITLE:
+                case SET_ACTION_BAR:
+                    ProtocolUtils.writeString(buf, component);
+                    break;
+                case SET_TIMES:
+                    buf.writeInt(fadeIn);
+                    buf.writeInt(stay);
+                    buf.writeInt(fadeOut);
+                    break;
+                case HIDE:
+                case RESET:
+                    break;
+            }
+        } else {
+            switch (action) {
+                case SET_TITLE:
+                case SET_SUBTITLE:
+                    ProtocolUtils.writeString(buf, component);
+                    break;
+                case SET_TIMES_OLD:
+                    buf.writeInt(fadeIn);
+                    buf.writeInt(stay);
+                    buf.writeInt(fadeOut);
+                    break;
+                case HIDE_OLD:
+                case RESET_OLD:
+                    break;
+            }
+        }
+    }
+
+    public int getAction() {
+        return action;
+    }
+
+    public void setAction(int action) {
+        this.action = action;
+    }
+
+    public String getComponent() {
+        return component;
+    }
+
+    public void setComponent(String component) {
+        this.component = component;
+    }
+
+    public int getFadeIn() {
+        return fadeIn;
+    }
+
+    public void setFadeIn(int fadeIn) {
+        this.fadeIn = fadeIn;
+    }
+
+    public int getStay() {
+        return stay;
+    }
+
+    public void setStay(int stay) {
+        this.stay = stay;
+    }
+
+    public int getFadeOut() {
+        return fadeOut;
+    }
+
+    public void setFadeOut(int fadeOut) {
+        this.fadeOut = fadeOut;
+    }
+
+    public static TitlePacket hideForProtocolVersion(int protocolVersion) {
+        TitlePacket packet = new TitlePacket();
+        packet.setAction(protocolVersion >= ProtocolConstants.MINECRAFT_1_11 ? TitlePacket.HIDE : TitlePacket.HIDE_OLD);
+        return packet;
+    }
+
+    public static TitlePacket resetForProtocolVersion(int protocolVersion) {
+        TitlePacket packet = new TitlePacket();
+        packet.setAction(protocolVersion >= ProtocolConstants.MINECRAFT_1_11 ? TitlePacket.RESET : TitlePacket.RESET_OLD);
+        return packet;
+    }
+
+    public static TitlePacket timesForProtocolVersion(int protocolVersion) {
+        TitlePacket packet = new TitlePacket();
+        packet.setAction(protocolVersion >= ProtocolConstants.MINECRAFT_1_11 ? TitlePacket.SET_TIMES : TitlePacket.SET_TIMES_OLD);
+        return packet;
+    }
+
+    @Override
+    public String toString() {
+        return "TitlePacket{" +
+                "action=" + action +
+                ", component='" + component + '\'' +
+                ", fadeIn=" + fadeIn +
+                ", stay=" + stay +
+                ", fadeOut=" + fadeOut +
+                '}';
+    }
+}