#831 Cleanup, finalization

- Handle AsyncPlayerPreLoginEvent in main PlayerListener class: Spigot emits it in offline mode, whereas offline CraftBukkit doesn't
- Remove listener for sync PlayerPreLoginEvent; not fired by offline CraftBukkit either
- Add warning when offline CraftBukkit is detected and single session setting is enabled

src/main/java/fr/xephi/authme/AuthMe.java

@@ -20,14 +20,12 @@ import fr.xephi.authme.hooks.BungeeCordMessage;
 import fr.xephi.authme.hooks.PluginHooks;
 import fr.xephi.authme.initialization.DataFolder;
 import fr.xephi.authme.initialization.MetricsStarter;
-import fr.xephi.authme.listener.AsyncSingleSessionListener;
 import fr.xephi.authme.listener.BlockListener;
 import fr.xephi.authme.listener.EntityListener;
 import fr.xephi.authme.listener.PlayerListener;
 import fr.xephi.authme.listener.PlayerListener16;
 import fr.xephi.authme.listener.PlayerListener18;
 import fr.xephi.authme.listener.ServerListener;
-import fr.xephi.authme.listener.SyncSingleSessionListener;
 import fr.xephi.authme.output.ConsoleFilter;
 import fr.xephi.authme.output.Log4JFilter;
 import fr.xephi.authme.output.MessageKey;
@@ -52,11 +50,10 @@ import fr.xephi.authme.util.BukkitService;
 import fr.xephi.authme.util.FileUtils;
 import fr.xephi.authme.util.GeoLiteAPI;
 import fr.xephi.authme.util.MigrationService;
+import fr.xephi.authme.util.ServerUtils;
 import fr.xephi.authme.util.StringUtils;
 import fr.xephi.authme.util.Utils;
 import fr.xephi.authme.util.ValidationService;
-import fr.xephi.authme.util.ServerUtils;
-
 import org.apache.logging.log4j.LogManager;
 import org.bukkit.Bukkit;
 import org.bukkit.Location;
@@ -310,6 +307,13 @@ public class AuthMe extends JavaPlugin {
             && settings.getProperty(PluginSettings.SESSIONS_ENABLED)) {
             ConsoleLogger.warning("WARNING!!! You set session timeout to 0, this may cause security issues!");
         }
+
+        // Single session not possible on CraftBukkit
+        if (settings.getProperty(RestrictionSettings.FORCE_SINGLE_SESSION)
+            && !Bukkit.getOnlineMode() && !ServerUtils.isSpigot()) {
+            ConsoleLogger.warning("WARNING: You have force single session enabled but are not running on Spigot. "
+                + "This feature is not supported on CraftBukkit in offline mode");
+        }
     }
 
     /**
@@ -338,13 +342,6 @@ public class AuthMe extends JavaPlugin {
             pluginManager.registerEvents(injector.getSingleton(PlayerListener18.class), this);
         } catch (ClassNotFoundException ignore) {
         }
-
-        // Choose the right SingleSessionListener
-        if(Bukkit.getOnlineMode() || ServerUtils.isSpigot()) {
-            pluginManager.registerEvents(injector.getSingleton(AsyncSingleSessionListener.class), this);
-        } else {
-            pluginManager.registerEvents(injector.getSingleton(SyncSingleSessionListener.class), this);
-        }
     }
 
     private void reloadSupportHook() {

src/main/java/fr/xephi/authme/listener/AsyncSingleSessionListener.java

@@ -1,39 +0,0 @@
-package fr.xephi.authme.listener;
-
-import javax.inject.Inject;
-
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.EventPriority;
-import org.bukkit.event.Listener;
-import org.bukkit.event.player.AsyncPlayerPreLoginEvent;
-
-import fr.xephi.authme.output.Messages;
-
-/*
- *  This listener is registered only if the server is in online-mode or the implementation is Spigot.
- *  The reason is that only Spigot fires the Async version of the event on an offline-mode server!
- */
-public class AsyncSingleSessionListener implements Listener {
-
-    @Inject
-    private Messages m;
-    @Inject
-    private OnJoinVerifier onJoinVerifier;
-
-    @EventHandler(priority = EventPriority.LOWEST)
-    public void onSyncPreLogin(AsyncPlayerPreLoginEvent event) {
-        if(event.getLoginResult() != AsyncPlayerPreLoginEvent.Result.ALLOWED) {
-            return;
-        }
-
-        final String name = event.getName();
-
-        try {
-            onJoinVerifier.checkSingleSession(name);
-        } catch (FailedVerificationException e) {
-            event.setKickMessage(m.retrieveSingle(e.getReason(), e.getArgs()));
-            event.setLoginResult(AsyncPlayerPreLoginEvent.Result.KICK_OTHER);
-            return;
-        }
-    }
-}

src/main/java/fr/xephi/authme/listener/PlayerListener.java

@@ -195,6 +195,26 @@ public class PlayerListener implements Listener {
         }
     }
 
+    // Note: AsyncPlayerPreLoginEvent is not fired by all servers in offline mode
+    // e.g. CraftBukkit does not. So we need to run crucial things in onPlayerLogin
+    // We have no performance improvements if we do the same thing on two different events
+    // The single session feature only works with the AsyncPlayerPreLoginEvent, i.e. it does not work
+    // with CraftBukkit, cf. issue #831
+    @EventHandler(priority = EventPriority.LOWEST)
+    public void onAsyncPreLogin(AsyncPlayerPreLoginEvent event) {
+        if (!AsyncPlayerPreLoginEvent.Result.ALLOWED.equals(event.getLoginResult())) {
+            return;
+        }
+
+        final String name = event.getName();
+        try {
+            onJoinVerifier.checkSingleSession(name);
+        } catch (FailedVerificationException e) {
+            event.setKickMessage(m.retrieveSingle(e.getReason(), e.getArgs()));
+            event.setLoginResult(AsyncPlayerPreLoginEvent.Result.KICK_OTHER);
+        }
+    }
+
     @EventHandler(priority = EventPriority.LOW)
     public void onPlayerJoin(PlayerJoinEvent event) {
         final Player player = event.getPlayer();
@@ -214,17 +234,15 @@ public class PlayerListener implements Listener {
         }
 
         final String name = player.getName();
-        final String lowerName = name.toLowerCase();
-
         try {
             // Fast stuff
-            // onJoinVerifier.checkSingleSession(lowerName);
             onJoinVerifier.checkIsValidName(name);
             
             // Get the auth later as this may cause the single session check to fail
             // Slow stuff
             final PlayerAuth auth = dataSource.getAuth(player.getName());
             final boolean isAuthAvailable = (auth != null);
+            final String lowerName = name.toLowerCase();
             onJoinVerifier.checkAntibot(lowerName, isAuthAvailable);
             onJoinVerifier.checkKickNonRegistered(isAuthAvailable);
             onJoinVerifier.checkNameCasing(player, auth);

src/main/java/fr/xephi/authme/listener/SyncSingleSessionListener.java

@@ -1,41 +0,0 @@
-package fr.xephi.authme.listener;
-
-import javax.inject.Inject;
-
-import org.bukkit.event.EventHandler;
-import org.bukkit.event.EventPriority;
-import org.bukkit.event.Listener;
-import org.bukkit.event.player.PlayerPreLoginEvent;
-
-import fr.xephi.authme.output.Messages;
-
-/*
- *  This listener is registered only if the server is in offline-mode and the implementation is not Spigot.
- *  The reason is that only Spigot fires the Async version of this event on an offline-mode server!
- */
-public class SyncSingleSessionListener implements Listener {
-
-    @Inject
-    private Messages m;
-    @Inject
-    private OnJoinVerifier onJoinVerifier;
-
-    // Note: the PlayerPreLoginEvent causes the login thread to synchronize with the main thread
-    @SuppressWarnings("deprecation")
-    @EventHandler(priority = EventPriority.LOWEST)
-    public void onSyncPreLogin(PlayerPreLoginEvent event) {
-        if(event.getResult() != PlayerPreLoginEvent.Result.ALLOWED) {
-            return;
-        }
-
-        final String name = event.getName();
-
-        try {
-            onJoinVerifier.checkSingleSession(name);
-        } catch (FailedVerificationException e) {
-            event.setKickMessage(m.retrieveSingle(e.getReason(), e.getArgs()));
-            event.setResult(PlayerPreLoginEvent.Result.KICK_OTHER);
-            return;
-        }
-    }
-}

src/main/java/fr/xephi/authme/util/ServerUtils.java

@@ -1,6 +1,9 @@
 package fr.xephi.authme.util;
 
-public class ServerUtils {
+public final class ServerUtils {
+
+    private ServerUtils() {
+    }
 
     /**
      * Check if the server implementation is based on Spigot

src/test/java/fr/xephi/authme/listener/BlockListenerTest.java

@@ -9,9 +9,6 @@ import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.runners.MockitoJUnitRunner;
 
-import fr.xephi.authme.listener.BlockListener;
-import fr.xephi.authme.listener.ListenerService;
-
 import static org.mockito.BDDMockito.given;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -21,7 +18,7 @@ import static org.mockito.Mockito.verifyNoMoreInteractions;
  * Test for {@link BlockListener}.
  */
 @RunWith(MockitoJUnitRunner.class)
-public class AuthMeBlockListenerTest {
+public class BlockListenerTest {
 
     @InjectMocks
     private BlockListener listener;

src/test/java/fr/xephi/authme/listener/ListenerConsistencyTest.java

@@ -1,14 +1,6 @@
 package fr.xephi.authme.listener;
 
 import com.google.common.collect.Sets;
-
-import fr.xephi.authme.listener.BlockListener;
-import fr.xephi.authme.listener.EntityListener;
-import fr.xephi.authme.listener.PlayerListener;
-import fr.xephi.authme.listener.PlayerListener16;
-import fr.xephi.authme.listener.PlayerListener18;
-import fr.xephi.authme.listener.ServerListener;
-
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.junit.Test;
@@ -36,7 +28,7 @@ public final class ListenerConsistencyTest {
         "PlayerListener#onPlayerJoin", "PlayerListener#onPlayerLogin",
         "PlayerListener#onPlayerQuit", "ServerListener#onPluginDisable",
         "ServerListener#onServerPing", "ServerListener#onPluginEnable",
-        "PlayerListener#onJoinMessage", "PlayerListener#onLoginSingleSession");
+        "PlayerListener#onJoinMessage", "PlayerListener#onAsyncPreLogin");
 
     @Test
     public void shouldSetIgnoreCancelledToTrue() {

src/test/java/fr/xephi/authme/listener/ListenerServiceTest.java

@@ -6,7 +6,6 @@ import ch.jalu.injector.testing.InjectDelayed;
 import fr.xephi.authme.cache.auth.PlayerCache;
 import fr.xephi.authme.datasource.DataSource;
 import fr.xephi.authme.hooks.PluginHooks;
-import fr.xephi.authme.listener.ListenerService;
 import fr.xephi.authme.settings.Settings;
 import fr.xephi.authme.settings.properties.RegistrationSettings;
 import fr.xephi.authme.util.ValidationService;

src/test/java/fr/xephi/authme/listener/OnJoinVerifierTest.java

@@ -4,8 +4,6 @@ import fr.xephi.authme.AntiBot;
 import fr.xephi.authme.TestHelper;
 import fr.xephi.authme.cache.auth.PlayerAuth;
 import fr.xephi.authme.datasource.DataSource;
-import fr.xephi.authme.listener.FailedVerificationException;
-import fr.xephi.authme.listener.OnJoinVerifier;
 import fr.xephi.authme.output.MessageKey;
 import fr.xephi.authme.output.Messages;
 import fr.xephi.authme.permission.PermissionsManager;

src/test/java/fr/xephi/authme/util/ServerUtilsTest.java

@@ -0,0 +1,19 @@
+package fr.xephi.authme.util;
+
+import org.junit.Test;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+/**
+ * Test for {@link ServerUtils}.
+ */
+public class ServerUtilsTest {
+
+    @Test
+    public void shouldReturnTrueForSpigotImplementation() {
+        // Spigot is a provided dependency of the project, so the ClassLoader knows about it
+        assertThat(ServerUtils.isSpigot(), equalTo(true));
+    }
+
+}