Handle some Exceptions caused eg. by missing network during shutdown

lib/src/main/java/xyz/gianlu/librespot/core/Session.java

@@ -388,7 +388,7 @@ private void authenticate(@NotNull Authentication.LoginCredentials credentials)
      *                   {@code true} for {@link Session#reconnect()}.
      */
     private void authenticatePartial(@NotNull Authentication.LoginCredentials credentials, boolean removeLock) throws IOException, GeneralSecurityException, SpotifyAuthenticationException {
-        if (cipherPair == null) throw new IllegalStateException("Connection not established!");
+        if (conn == null || cipherPair == null) throw new IllegalStateException("Connection not established!");
 
         Authentication.ClientResponseEncrypted clientResponseEncrypted = Authentication.ClientResponseEncrypted.newBuilder()
                 .setLoginCredentials(credentials)
@@ -409,7 +409,6 @@ private void authenticatePartial(@NotNull Authentication.LoginCredentials creden
 
             receiver = new Receiver();
 
-
             byte[] bytes0x0f = new byte[20];
             random().nextBytes(bytes0x0f);
             sendUnchecked(Packet.Type.Unknown_0x0f, bytes0x0f);
@@ -452,6 +451,8 @@ private void authenticatePartial(@NotNull Authentication.LoginCredentials creden
     public void close() throws IOException {
         LOGGER.info("Closing session. {deviceId: {}}", inner.deviceId);
 
+        if (scheduledReconnect != null) scheduledReconnect.cancel(true);
+
         closing = true;
 
         scheduler.shutdownNow();
@@ -513,6 +514,9 @@ public void close() throws IOException {
     }
 
     private void sendUnchecked(Packet.Type cmd, byte[] payload) throws IOException {
+        if (conn == null)
+            throw new IOException("Cannot write to missing connection.");
+
         cipherPair.sendEncoded(conn.out, cmd.val, payload);
     }
 
@@ -692,6 +696,9 @@ public Configuration configuration() {
     }
 
     private void reconnect() {
+        if (closing)
+            return;
+
         synchronized (reconnectionListeners) {
             reconnectionListeners.forEach(ReconnectionListener::onConnectionDropped);
         }
@@ -716,6 +723,9 @@ private void reconnect() {
                 reconnectionListeners.forEach(ReconnectionListener::onConnectionEstablished);
             }
         } catch (IOException | GeneralSecurityException | SpotifyAuthenticationException ex) {
+            if (closing)
+                return;
+
             conn = null;
             LOGGER.error("Failed reconnecting, retrying in 10 seconds...", ex);
 
@@ -1310,7 +1320,7 @@ public void run() {
                         continue;
                     }
                 } catch (IOException | GeneralSecurityException ex) {
-                    if (running) {
+                    if (running && !closing) {
                         LOGGER.error("Failed reading packet!", ex);
                         reconnect();
                     }

player/src/main/java/xyz/gianlu/librespot/player/state/DeviceStateHandler.java

@@ -44,6 +44,7 @@
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.util.*;
+import java.util.concurrent.RejectedExecutionException;
 
 /**
  * @author Gianlu
@@ -65,6 +66,7 @@ public final class DeviceStateHandler implements Closeable, DealerClient.Message
     private final Connect.PutStateRequest.Builder putState;
     private final AsyncWorker<Connect.PutStateRequest> putStateWorker;
     private volatile String connectionId = null;
+    private volatile boolean closing = false;
 
     public DeviceStateHandler(@NotNull Session session, @NotNull PlayerConfiguration conf) {
         this.session = session;
@@ -226,7 +228,11 @@ public synchronized void updateState(@NotNull Connect.PutStateReason reason, int
                 .setClientSideTimestamp(TimeProvider.currentTimeMillis())
                 .getDeviceBuilder().setDeviceInfo(deviceInfo).setPlayerState(state);
 
-        putStateWorker.submit(putState.build());
+        try {
+            putStateWorker.submit(putState.build());
+        } catch (RejectedExecutionException ex) {
+            if (!closing) LOGGER.error("Failed to submit update state task.", ex);
+        }
     }
 
     public synchronized int getVolume() {
@@ -244,6 +250,8 @@ public void setVolume(int val) {
 
     @Override
     public void close() {
+        closing = true;
+
         session.dealer().removeMessageListener(this);
         session.dealer().removeRequestListener(this);