Merge branch 'plugin-messages'

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

@@ -1,6 +1,7 @@
 package com.velocitypowered.api.proxy;
 
 import com.velocitypowered.api.command.CommandSource;
+import com.velocitypowered.api.proxy.messages.ChannelMessageSource;
 import com.velocitypowered.api.server.ServerInfo;
 import com.velocitypowered.api.util.MessagePosition;
 import net.kyori.text.Component;
@@ -12,7 +13,7 @@ import java.util.UUID;
 /**
  * Represents a player who is connected to the proxy.
  */
-public interface Player extends CommandSource, InboundConnection {
+public interface Player extends CommandSource, InboundConnection, ChannelMessageSource {
     /**
      * Returns the player's current username.
      * @return the username

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

@@ -4,6 +4,7 @@ import com.velocitypowered.api.command.CommandSource;
 import com.velocitypowered.api.command.CommandManager;
 import com.velocitypowered.api.event.EventManager;
 import com.velocitypowered.api.plugin.PluginManager;
+import com.velocitypowered.api.proxy.messages.ChannelRegistrar;
 import com.velocitypowered.api.scheduler.Scheduler;
 import com.velocitypowered.api.server.ServerInfo;
 
@@ -101,4 +102,10 @@ public interface ProxyServer {
      * @return the scheduler instance
      */
     Scheduler getScheduler();
+
+    /**
+     * Gets the {@link ChannelRegistrar} instance.
+     * @return the channel registrar
+     */
+    ChannelRegistrar getChannelRegistrar();
 }

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

@@ -1,11 +1,12 @@
 package com.velocitypowered.api.proxy;
 
+import com.velocitypowered.api.proxy.messages.ChannelMessageSource;
 import com.velocitypowered.api.server.ServerInfo;
 
 /**
  * Represents a connection to a backend server from the proxy for a client.
  */
-public interface ServerConnection {
+public interface ServerConnection extends ChannelMessageSource {
     ServerInfo getServerInfo();
 
     Player getPlayer();

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelIdentifier.java

@@ -0,0 +1,8 @@
+package com.velocitypowered.api.proxy.messages;
+
+/**
+ * Represents a kind of channel identifier.
+ */
+public interface ChannelIdentifier {
+    String getId();
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelMessageSource.java

@@ -0,0 +1,4 @@
+package com.velocitypowered.api.proxy.messages;
+
+public interface ChannelMessageSource {
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelRegistrar.java

@@ -0,0 +1,11 @@
+package com.velocitypowered.api.proxy.messages;
+
+/**
+ * Represents an interface to register and unregister {@link MessageHandler} instances for handling plugin messages from
+ * the client or the server.
+ */
+public interface ChannelRegistrar {
+    void register(MessageHandler handler, ChannelIdentifier... identifiers);
+
+    void unregister(ChannelIdentifier... identifiers);
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/ChannelSide.java

@@ -0,0 +1,6 @@
+package com.velocitypowered.api.proxy.messages;
+
+public enum ChannelSide {
+    FROM_SERVER,
+    FROM_CLIENT
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/LegacyChannelIdentifier.java

@@ -0,0 +1,48 @@
+package com.velocitypowered.api.proxy.messages;
+
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+
+import java.util.Objects;
+
+/**
+ * Reperesents a legacy channel identifier (for Minecraft 1.12 and below). For modern 1.13 plugin messages, please see
+ * {@link MinecraftChannelIdentifier}. This class is immutable and safe for multi-threaded use.
+ */
+public final class LegacyChannelIdentifier implements ChannelIdentifier {
+    private final String name;
+
+    public LegacyChannelIdentifier(String name) {
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(name), "provided name is empty");
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return "LegacyChannelIdentifier{" +
+                "name='" + name + '\'' +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        LegacyChannelIdentifier that = (LegacyChannelIdentifier) o;
+        return Objects.equals(name, that.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(name);
+    }
+
+    @Override
+    public String getId() {
+        return name;
+    }
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/MessageHandler.java

@@ -0,0 +1,10 @@
+package com.velocitypowered.api.proxy.messages;
+
+public interface MessageHandler {
+    ForwardStatus handle(ChannelMessageSource source, ChannelSide side, byte[] data);
+
+    enum ForwardStatus {
+        FORWARD,
+        HANDLED
+    }
+}

api/src/main/java/com/velocitypowered/api/proxy/messages/MinecraftChannelIdentifier.java

@@ -0,0 +1,69 @@
+package com.velocitypowered.api.proxy.messages;
+
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+
+import java.util.Objects;
+import java.util.regex.Pattern;
+
+/**
+ * Represents a Minecraft 1.13+ channel identifier. This class is immutable and safe for multi-threaded use.
+ */
+public final class MinecraftChannelIdentifier implements ChannelIdentifier {
+    private static final Pattern VALID_IDENTIFIER_REGEX = Pattern.compile("[a-z0-9\\-_]+");
+
+    private final String namespace;
+    private final String name;
+
+    private MinecraftChannelIdentifier(String namespace, String name) {
+        this.namespace = namespace;
+        this.name = name;
+    }
+
+    public static MinecraftChannelIdentifier forDefaultNamespace(String name) {
+        return new MinecraftChannelIdentifier("minecraft", name);
+    }
+
+    public static MinecraftChannelIdentifier create(String namespace, String name) {
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(namespace), "namespace is null or empty");
+        Preconditions.checkArgument(!Strings.isNullOrEmpty(name), "namespace is null or empty");
+        Preconditions.checkArgument(VALID_IDENTIFIER_REGEX.matcher(namespace).matches(), "namespace is not valid");
+        Preconditions.checkArgument(VALID_IDENTIFIER_REGEX.matcher(name).matches(), "name is not valid");
+        return new MinecraftChannelIdentifier(namespace, name);
+    }
+
+    public String getNamespace() {
+        return namespace;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public String toString() {
+        return "MinecraftChannelIdentifier{" +
+                "namespace='" + namespace + '\'' +
+                ", name='" + name + '\'' +
+                '}';
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        MinecraftChannelIdentifier that = (MinecraftChannelIdentifier) o;
+        return Objects.equals(namespace, that.namespace) &&
+                Objects.equals(name, that.name);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(namespace, name);
+    }
+
+    @Override
+    public String getId() {
+        return namespace + ":" + name;
+    }
+}