Basic protocol

src/main/java/me/mrletsplay/shareclientcore/connection/ConnectionException.java

@@ -0,0 +1,25 @@
+package me.mrletsplay.shareclientcore.connection;
+
+public class ConnectionException extends Exception {
+
+	private static final long serialVersionUID = -6133726852202889620L;
+
+	public ConnectionException() {
+		super();
+	}
+
+	public ConnectionException(String message, Throwable cause) {
+		super(message, cause);
+	}
+
+	public ConnectionException(String message) {
+		super(message);
+	}
+
+	public ConnectionException(Throwable cause) {
+		super(cause);
+	}
+
+
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/DummyConnection.java

@@ -1,31 +1,31 @@
 package me.mrletsplay.shareclientcore.connection;
 
-import java.io.IOException;
+import me.mrletsplay.shareclientcore.connection.message.Message;
 
 public class DummyConnection implements RemoteConnection {
 
 	@Override
-	public void connect() throws IOException, InterruptedException {
+	public void connect(String sessionID) throws ConnectionException {
 
 	}
 
 	@Override
-	public int retrieveSiteID() {
+	public int getSiteID() {
 		return 0;
 	}
 
 	@Override
-	public void send(Change... changes) {
+	public void send(Message message) {
 
 	}
 
 	@Override
-	public void addListener(RemoteListener listener) {
+	public void addListener(MessageListener listener) {
 
 	}
 
 	@Override
-	public void removeListener(RemoteListener listener) {
+	public void removeListener(MessageListener listener) {
 
 	}
 

src/main/java/me/mrletsplay/shareclientcore/connection/MessageListener.java

@@ -0,0 +1,12 @@
+package me.mrletsplay.shareclientcore.connection;
+
+import me.mrletsplay.shareclientcore.connection.message.Message;
+
+/**
+ * A message listener that can receive remote messages
+ */
+public interface MessageListener {
+
+	public void onMessage(Message message);
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/RemoteConnection.java

@@ -1,20 +1,22 @@
 package me.mrletsplay.shareclientcore.connection;
 
-import java.io.IOException;
+import me.mrletsplay.shareclientcore.connection.message.Message;
 
 /**
  * Represents a connection to a remote user or server
  */
 public interface RemoteConnection {
 
-	public void connect() throws IOException, InterruptedException;
+	public static final int PROTOCOL_VERSION = 1;
 
-	public int retrieveSiteID();
+	public void connect(String sessionID) throws ConnectionException;
 
-	public void send(Change... changes);
+	public int getSiteID();
 
-	public void addListener(RemoteListener listener);
+	public void send(Message message) throws ConnectionException;
 
-	public void removeListener(RemoteListener listener);
+	public void addListener(MessageListener listener);
+
+	public void removeListener(MessageListener listener);
 
 }

src/main/java/me/mrletsplay/shareclientcore/connection/RemoteListener.java

@@ -1,10 +0,0 @@
-package me.mrletsplay.shareclientcore.connection;
-
-/**
- * Represents something that can receive remote changes
- */
-public interface RemoteListener {
-
-	public void onRemoteChange(Change... changes);
-
-}

src/main/java/me/mrletsplay/shareclientcore/connection/SerializableObject.java

@@ -0,0 +1,10 @@
+package me.mrletsplay.shareclientcore.connection;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public interface SerializableObject {
+
+	public void serialize(DataOutputStream out) throws IOException;
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/WebSocketConnection.java

@@ -1,109 +1,86 @@
 package me.mrletsplay.shareclientcore.connection;
 
-import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
-import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.util.HashSet;
 import java.util.Map;
-import java.util.Random;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
 
 import org.java_websocket.client.WebSocketClient;
 import org.java_websocket.handshake.ServerHandshake;
 
-import me.mrletsplay.shareclientcore.document.Char;
-import me.mrletsplay.shareclientcore.document.Identifier;
+import me.mrletsplay.shareclientcore.connection.message.ClientHelloMessage;
+import me.mrletsplay.shareclientcore.connection.message.Message;
+import me.mrletsplay.shareclientcore.connection.message.ServerHelloMessage;
 
 public class WebSocketConnection implements RemoteConnection {
 
 	private WSClient client;
-	private Set<RemoteListener> listeners;
+	private String username;
+	private Set<MessageListener> listeners;
+	private int siteID;
 
-	public WebSocketConnection(URI uri, Map<String, String> httpHeaders) {
+	private Object wait = new Object();
+	private boolean helloReceived;
+	private ConnectionException connectException;
+
+	public WebSocketConnection(URI uri, String username, Map<String, String> httpHeaders) {
 		this.client = new WSClient(uri, httpHeaders);
+		this.username = username;
 		this.listeners = new HashSet<>();
 	}
 
-	public WebSocketConnection(URI uri) {
-		this(uri, null);
+	public WebSocketConnection(URI uri, String username) {
+		this(uri, username, null);
 	}
 
 	@Override
-	public void connect() throws IOException, InterruptedException {
-		if(!client.connectBlocking()) throw new IOException("Failed to connect to WebSocket server");
-	}
-
-	@Override
-	public int retrieveSiteID() {
-		// TODO: implement
-		return new Random().nextInt();
-	}
-
-	@Override
-	public void send(Change... changes) {
-		for(Change c : changes) {
-			client.send(serialize(c));
+	public void connect(String sessionID) throws ConnectionException {
+		try {
+			if(!client.connectBlocking(30, TimeUnit.SECONDS)) throw new IOException("Failed to connect to WebSocket server");
+			send(new ClientHelloMessage(username, sessionID));
+			wait.wait(30_000L);
+			if(!helloReceived) throw new ConnectionException("Server did not send hello");
+			if(connectException != null) throw connectException;
+		} catch (InterruptedException | IOException e) {
+			throw new ConnectionException("Failed to establish connection", e);
 		}
 	}
 
 	@Override
-	public void addListener(RemoteListener listener) {
+	public int getSiteID() {
+		return siteID;
+	}
+
+	@Override
+	public void send(Message message) throws ConnectionException {
+		ByteArrayOutputStream bOut = new ByteArrayOutputStream();
+		DataOutputStream dOut = new DataOutputStream(bOut);
+
+		try {
+			dOut.writeUTF(message.getType().name());
+			message.serialize(dOut);
+		} catch (IOException e) {
+			throw new ConnectionException("Failed to serialize message", e);
+		}
+
+		client.send(bOut.toByteArray());
+	}
+
+	@Override
+	public void addListener(MessageListener listener) {
 		listeners.add(listener);
 	}
 
 	@Override
-	public void removeListener(RemoteListener listener) {
+	public void removeListener(MessageListener listener) {
 		listeners.remove(listener);
 	}
 
-	private byte[] serialize(Change change) {
-		try {
-			ByteArrayOutputStream bOut = new ByteArrayOutputStream();
-			DataOutputStream dOut = new DataOutputStream(bOut);
-			dOut.writeInt(change.document());
-			dOut.writeUTF(change.type().name());
-
-			Char ch = change.character();
-			dOut.writeInt(ch.position().length);
-			for(int i = 0; i < ch.position().length; i++) {
-				Identifier id = ch.position()[i];
-				dOut.writeInt(id.digit());
-				dOut.writeInt(id.site());
-			}
-
-			dOut.writeInt(ch.lamport());
-			dOut.writeChar(ch.value());
-			return bOut.toByteArray();
-		}catch(IOException e) {
-			throw new RuntimeException("Something went very wrong", e);
-		}
-	}
-
-	private Change deserialize(byte[] bytes) {
-		try {
-			DataInputStream dIn = new DataInputStream(new ByteArrayInputStream(bytes));
-			int document = dIn.readInt();
-			ChangeType type = ChangeType.valueOf(dIn.readUTF());
-
-			Identifier[] pos = new Identifier[dIn.readInt()];
-			for(int i = 0; i < pos.length; i++) {
-				pos[i] = new Identifier(dIn.readInt(), dIn.readInt());
-			}
-
-			int lamport = dIn.readInt();
-			char value = dIn.readChar();
-			return new Change(document, type, new Char(pos, lamport, value));
-		}catch(IllegalArgumentException e) {
-			throw new IllegalArgumentException("Failed to deserialize change", e);
-		}catch(IOException e) {
-			throw new RuntimeException("Something went very wrong", e);
-		}
-	}
-
 	private class WSClient extends WebSocketClient {
 
 		public WSClient(URI serverUri) {
@@ -116,7 +93,7 @@ public class WebSocketConnection implements RemoteConnection {
 
 		@Override
 		public void onOpen(ServerHandshake handshakedata) {
-			// TODO: request site id
+
 		}
 
 		@Override
@@ -126,9 +103,28 @@ public class WebSocketConnection implements RemoteConnection {
 
 		@Override
 		public void onMessage(ByteBuffer bytes) {
-			byte[] bytesArray = new byte[bytes.remaining()];
-			bytes.get(bytesArray);
-			listeners.forEach(l -> l.onRemoteChange(deserialize(bytesArray)));
+			Message m;
+			try {
+				m = Message.deserialize(bytes);
+			}catch(IOException e) {
+				e.printStackTrace(); // TODO: custom logging (e.g. via error callback)
+				return;
+			}
+
+			if(m instanceof ServerHelloMessage hello) {
+				helloReceived = true;
+				siteID = hello.siteID();
+
+				if(hello.protocolVersion() != PROTOCOL_VERSION) {
+					connectException = new ConnectionException(String.format("Protocol version mismatch: (Server has %s, Client has %s)", hello.protocolVersion(), PROTOCOL_VERSION));
+					close();
+				}
+
+				wait.notifyAll();
+				return;
+			}
+
+			listeners.forEach(l -> l.onMessage(m));
 		}
 
 		@Override

src/main/java/me/mrletsplay/shareclientcore/connection/message/BasicMessage.java

@@ -0,0 +1,16 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public record BasicMessage(MessageType type) implements Message {
+
+	@Override
+	public MessageType getType() {
+		return type;
+	}
+
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {}
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/ChangeMessage.java

@@ -0,0 +1,33 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+import me.mrletsplay.shareclientcore.connection.Change;
+import me.mrletsplay.shareclientcore.connection.ChangeType;
+import me.mrletsplay.shareclientcore.document.Char;
+
+public record ChangeMessage(Change change) implements Message {
+
+	@Override
+	public MessageType getType() {
+		return MessageType.CHANGE;
+	}
+
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {
+		out.writeInt(change.document());
+		out.writeUTF(change.type().name());
+		change.character().serialize(out);
+	}
+
+	public static ChangeMessage deserialize(DataInputStream in) throws IOException {
+		try {
+			return new ChangeMessage(new Change(in.readInt(), ChangeType.valueOf(in.readUTF()), Char.deserialize(in)));
+		}catch(IllegalArgumentException e) {
+			throw new IOException("Invalid change type", e);
+		}
+	}
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/ClientHelloMessage.java

@@ -0,0 +1,24 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public record ClientHelloMessage(String username, String sessionID) implements Message {
+
+	@Override
+	public MessageType getType() {
+		return MessageType.CLIENT_HELLO;
+	}
+
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {
+		out.writeUTF(username);
+		out.writeUTF(sessionID);
+	}
+
+	public static ClientHelloMessage deserialize(DataInputStream in) throws IOException {
+		return new ClientHelloMessage(in.readUTF(), in.readUTF());
+	}
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/Message.java

@@ -0,0 +1,38 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.ByteArrayInputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+import me.mrletsplay.shareclientcore.connection.SerializableObject;
+
+public interface Message extends SerializableObject {
+
+	public MessageType getType();
+
+	public static Message deserialize(ByteBuffer buffer) throws IOException {
+		byte[] bytesArray = new byte[buffer.remaining()];
+		buffer.get(bytesArray);
+
+		try {
+			DataInputStream dIn = new DataInputStream(new ByteArrayInputStream(bytesArray));
+			MessageType type = MessageType.valueOf(dIn.readUTF());
+
+			Message m;
+			switch(type) {
+				case CLIENT_HELLO -> m = ClientHelloMessage.deserialize(dIn);
+				case SERVER_HELLO -> m = ServerHelloMessage.deserialize(dIn);
+				case PEER_JOIN -> m = PeerJoinMessage.deserialize(dIn);
+				case PEER_LEAVE -> m = PeerLeaveMessage.deserialize(dIn);
+				case CHANGE -> m = ChangeMessage.deserialize(dIn);
+				default -> m = new BasicMessage(type);
+			}
+
+			return m;
+		}catch(IllegalArgumentException e) {
+			throw new IOException("Invalid message type", e);
+		}
+	}
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/MessageType.java

@@ -0,0 +1,61 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+public enum MessageType {
+
+	/**
+	 * Client hello containing user information
+	 */
+	CLIENT_HELLO,
+
+	/**
+	 * Server hello containing protocol information
+	 */
+	SERVER_HELLO,
+
+	/**
+	 * Peer has joined
+	 */
+	PEER_JOIN,
+
+	/**
+	 * Peer has left
+	 */
+	PEER_LEAVE,
+
+	/**
+	 * Full synchronization message, containing the full contents of a file
+	 */
+	FULL_SYNC,
+
+	/**
+	 * Request for the synchronization of a particular file or all shared files
+	 */
+	REQUEST_FULL_SYNC,
+
+	/**
+	 * A single change made by one peer
+	 */
+	CHANGE,
+
+	/**
+	 * Request for the checksum of a file
+	 */
+	REQUEST_CHECKSUM,
+
+	/**
+	 * Checksum of a file
+	 */
+	CHECKSUM,
+
+	/**
+	 * Creation of a file
+	 */
+	CREATE_FILE,
+
+	/**
+	 * Deletion of a file
+	 */
+	DELETE_FILE,
+	;
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/PeerJoinMessage.java

@@ -0,0 +1,24 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public record PeerJoinMessage(String peerName, int peerSiteID) implements Message {
+
+	@Override
+	public MessageType getType() {
+		return MessageType.PEER_JOIN;
+	}
+
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {
+		out.writeUTF(peerName);
+		out.writeInt(peerSiteID);
+	}
+
+	public static PeerJoinMessage deserialize(DataInputStream in) throws IOException {
+		return new PeerJoinMessage(in.readUTF(), in.readInt());
+	}
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/PeerLeaveMessage.java

@@ -0,0 +1,23 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public record PeerLeaveMessage(int peerSiteID) implements Message {
+
+	@Override
+	public MessageType getType() {
+		return MessageType.PEER_LEAVE;
+	}
+
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {
+		out.writeInt(peerSiteID);
+	}
+
+	public static PeerLeaveMessage deserialize(DataInputStream in) throws IOException {
+		return new PeerLeaveMessage(in.readInt());
+	}
+
+}

src/main/java/me/mrletsplay/shareclientcore/connection/message/ServerHelloMessage.java

@@ -0,0 +1,24 @@
+package me.mrletsplay.shareclientcore.connection.message;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public record ServerHelloMessage(int protocolVersion, int siteID) implements Message {
+
+	@Override
+	public MessageType getType() {
+		return MessageType.SERVER_HELLO;
+	}
+
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {
+		out.writeInt(protocolVersion);
+		out.writeInt(siteID);
+	}
+
+	public static ServerHelloMessage deserialize(DataInputStream in) throws IOException {
+		return new ServerHelloMessage(in.readInt(), in.readInt());
+	}
+
+}

src/main/java/me/mrletsplay/shareclientcore/document/Char.java

@@ -1,9 +1,14 @@
 package me.mrletsplay.shareclientcore.document;
 
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.Objects;
 
-public record Char(Identifier[] position, int lamport, char value) {
+import me.mrletsplay.shareclientcore.connection.SerializableObject;
+
+public record Char(Identifier[] position, int lamport, char value) implements SerializableObject {
 
 	public static final Char START_OF_DOCUMENT = new Char(new Identifier[] { new Identifier(1, 0) }, 0, '^');
 	public static final Char END_OF_DOCUMENT = new Char(new Identifier[] { new Identifier(Util.BASE - 1, 0) }, 0, '$');
@@ -28,4 +33,28 @@ public record Char(Identifier[] position, int lamport, char value) {
 		return lamport == other.lamport && Arrays.equals(position, other.position) && value == other.value;
 	}
 
+	@Override
+	public void serialize(DataOutputStream out) throws IOException {
+		out.writeInt(position.length);
+		for(int i = 0; i < position.length; i++) {
+			Identifier id = position[i];
+			out.writeInt(id.digit());
+			out.writeInt(id.site());
+		}
+
+		out.writeInt(lamport);
+		out.writeChar(value);
+	}
+
+	public static Char deserialize(DataInputStream in) throws IOException {
+		Identifier[] pos = new Identifier[in.readInt()];
+		for(int i = 0; i < pos.length; i++) {
+			pos[i] = new Identifier(in.readInt(), in.readInt());
+		}
+
+		int lamport = in.readInt();
+		char value = in.readChar();
+		return new Char(pos, lamport, value);
+	}
+
 }

src/main/java/me/mrletsplay/shareclientcore/document/SharedDocument.java

@@ -6,10 +6,13 @@ import java.util.Set;
 
 import me.mrletsplay.shareclientcore.connection.Change;
 import me.mrletsplay.shareclientcore.connection.ChangeType;
+import me.mrletsplay.shareclientcore.connection.ConnectionException;
+import me.mrletsplay.shareclientcore.connection.MessageListener;
 import me.mrletsplay.shareclientcore.connection.RemoteConnection;
-import me.mrletsplay.shareclientcore.connection.RemoteListener;
+import me.mrletsplay.shareclientcore.connection.message.ChangeMessage;
+import me.mrletsplay.shareclientcore.connection.message.Message;
 
-public class SharedDocument implements RemoteListener {
+public class SharedDocument implements MessageListener {
 
 	private RemoteConnection connection;
 	private CharBag charBag;
@@ -27,7 +30,7 @@ public class SharedDocument implements RemoteListener {
 		charBag.add(Char.END_OF_DOCUMENT);
 
 		this.document = 0; // TODO: implement
-		this.site = connection.retrieveSiteID();
+		this.site = connection.getSiteID();
 		this.listeners = new HashSet<>();
 	}
 
@@ -53,7 +56,13 @@ public class SharedDocument implements RemoteListener {
 			charBefore = ch;
 		}
 
-		connection.send(changes);
+		for(Change c : changes) {
+			try {
+				connection.send(new ChangeMessage(c));
+			} catch (ConnectionException e) {
+				e.printStackTrace(); // TODO: throw error
+			}
+		}
 	}
 
 	/**
@@ -73,7 +82,14 @@ public class SharedDocument implements RemoteListener {
 			charBag.remove(toRemove);
 		}
 
-		connection.send(changes);
+
+		for(Change c : changes) {
+			try {
+				connection.send(new ChangeMessage(c));
+			} catch (ConnectionException e) {
+				e.printStackTrace(); // TODO: throw error
+			}
+		}
 	}
 
 	/**
@@ -120,8 +136,9 @@ public class SharedDocument implements RemoteListener {
 	}
 
 	@Override
-	public void onRemoteChange(Change... changes) {
-		for(Change c : changes) {
+	public void onMessage(Message message) {
+		if(message instanceof ChangeMessage change) {
+			Change c = change.change();
 			System.out.println("Change: " + c + " | " + Arrays.toString(c.character().position()));
 			switch(c.type()) {
 				case ADD -> remoteInsert(c.character());