1 files changed, 157 insertions, 0 deletions
diff --git a/src/main/java/de/bwlehrpool/bwlp_guac/AvailableClient.java b/src/main/java/de/bwlehrpool/bwlp_guac/AvailableClient.java
new file mode 100644
index 0000000..7c4ca80
--- /dev/null
+++ b/src/main/java/de/bwlehrpool/bwlp_guac/AvailableClient.java
@@ -0,0 +1,157 @@
+package de.bwlehrpool.bwlp_guac;
+
+import java.io.IOException;
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.apache.guacamole.protocol.GuacamoleConfiguration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import de.bwlehrpool.bwlp_guac.JsonClient.State;
+
+public class AvailableClient {
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(AvailableClient.class);
+
+	private static final AtomicLong CON_ID = new AtomicLong();
+
+	private final String clientip;
+
+	private String password;
+
+	private State state;
+
+	private String inUseBy;
+
+	private WrappedConnection connection;
+
+	private long deadline;
+
+	private long lastConnectionCheck;
+
+	private boolean connectionOk;
+
+	private final Object connCheckLock = new Object();
+
+	public AvailableClient(JsonClient source) {
+		this.clientip = source.clientip;
+		update(source);
+	}
+
+	/**
+	 * Update this client's state, resetting "in use" if appropriate. Ie, the
+	 * password changed, which would mean the remote VNC server was restarted, so it
+	 * can't possibly be in use by the old user anymore.
+	 */
+	public synchronized void update(JsonClient source) {
+		if (this.password == null || !this.password.equals(source.password)) {
+			if (source.state != State.OCCUPIED) {
+				if (this.inUseBy != null) {
+					LOGGER.info("Client " + this + "is available again");
+					this.inUseBy = null;
+					this.connection = null;
+				}
+			}
+			this.lastConnectionCheck = 0;
+			this.password = source.password;
+		}
+		this.state = source.state;
+		this.deadline = 0;
+	}
+
+	/**
+	 * Try to reserve this client for the given user.
+	 */
+	public synchronized boolean claim(String user) {
+		if (this.inUseBy != null || this.password == null || this.state != State.IDLE || user == null)
+			return false;
+		this.inUseBy = user;
+		this.connection = new WrappedConnection(this.clientip + "/" + CON_ID.incrementAndGet(), this);
+		this.state = State.OCCUPIED;
+		return true;
+	}
+
+	public synchronized boolean isInUseBy(String user) {
+		return (this.inUseBy != null && this.inUseBy.equals(user));
+	}
+
+	public synchronized WrappedConnection getConnection(String expectedOwner) {
+		if (isInUseBy(expectedOwner))
+			return this.connection;
+		return null;
+	}
+
+	public synchronized void releaseConnection(String expectedOwner) {
+		if (isInUseBy(expectedOwner)) {
+			LOGGER.info("Prematurely releasing client " + this);
+			this.inUseBy = null;
+			this.connection = null;
+		}
+	}
+
+	/**
+	 * If this connection is not returned by the sat server anymore, we keep it
+	 * around for another 5 minutes just in case.
+	 */
+	public boolean isTimeout(long NOW) {
+		if (deadline == 0) {
+			deadline = NOW + 300000;
+			return false;
+		}
+		return deadline < NOW;
+	}
+
+	@Override
+	public String toString() {
+		return clientip + "/" + state + "/" + inUseBy;
+	}
+
+	public GuacamoleConfiguration toGuacConfig() {
+		GuacamoleConfiguration cfg = new GuacamoleConfiguration();
+		cfg.setProtocol("vnc");
+		cfg.setParameter("hostname", this.clientip);
+		cfg.setParameter("port", Integer.toString(5900)); // TODO
+		cfg.setParameter("password", password);
+		return cfg;
+	}
+
+	/**
+	 * Check if the given VNC credentials actually work, so we avoid assigning a
+	 * bogus entry to a user.
+	 */
+	public boolean checkConnection(int retries) {
+		long now = System.currentTimeMillis();
+		synchronized (connCheckLock) {
+			if (now < this.lastConnectionCheck) {
+				this.lastConnectionCheck = 0;
+			}
+			if (now - this.lastConnectionCheck < 5000)
+				return this.connectionOk;
+			for (;;) {
+				try (VncConnection vnc = new VncConnection(this.clientip, 5900)) {
+					LOGGER.debug("VNC Version for " + this.clientip + " is " + vnc.handshake());
+					if (vnc.tryLogin(this.password)) {
+						this.lastConnectionCheck = now;
+						return this.connectionOk = true;
+					}
+				} catch (IOException e) {
+					LOGGER.info("Connection error VNC @ " + this, e);
+					if (retries-- > 0) {
+						try {
+							Thread.sleep(1000);
+						} catch (InterruptedException e1) {
+							Thread.currentThread().interrupt();
+							break;
+						}
+						continue;
+					}
+				}
+				break;
+			}
+			this.lastConnectionCheck = now;
+			this.password = null; // Render invalid, so ConnectionManager::getForUser() doesn't turn into an infinite loop
+			return this.connectionOk = false;
+		}
+	}
+
+}