Waterfall/BungeeCord-Patches/0067-Proof-methods-in-Plugin-PluginManager-against-concur.patch

From 076e7a2e1a2f118de921b5843e3baa4a75cadbbc Mon Sep 17 00:00:00 2001
From: A248 <theanandbeh@gmail.com>
Date: Mon, 21 Aug 2023 13:38:03 -0500
Subject: [PATCH] Proof methods in Plugin, PluginManager against concurrent
 access


diff --git a/api/src/main/java/net/md_5/bungee/api/plugin/Plugin.java b/api/src/main/java/net/md_5/bungee/api/plugin/Plugin.java
index 3d1e9a3a..b4d2dd51 100644
--- a/api/src/main/java/net/md_5/bungee/api/plugin/Plugin.java
+++ b/api/src/main/java/net/md_5/bungee/api/plugin/Plugin.java
@@ -113,17 +113,29 @@ public class Plugin
     }
 
     //
-    private ExecutorService service;
+    private volatile ExecutorService service; // Waterfall - mark volatile
 
     @Deprecated
     public ExecutorService getExecutorService()
     {
+        // Waterfall start - synchronize
+        ExecutorService service = this.service;
         if ( service == null )
         {
-            String name = ( getDescription() == null ) ? "unknown" : getDescription().getName();
-            service = Executors.newCachedThreadPool( new ThreadFactoryBuilder().setNameFormat( name + " Pool Thread #%1$d" )
-                    .setThreadFactory( new GroupedThreadFactory( this, name ) ).build() );
+            synchronized ( this )
+            {
+                service = this.service;
+                if ( service == null )
+                {
+                    String name = ( getDescription() == null ) ? "unknown" : getDescription().getName();
+                    service = Executors
+                            .newCachedThreadPool( new ThreadFactoryBuilder().setNameFormat( name + " Pool Thread #%1$d" )
+                                    .setThreadFactory( new GroupedThreadFactory( this, name ) ).build() );
+                    this.service = service;
+                }
+            }
         }
+        // Waterfall end
         return service;
     }
     //
diff --git a/api/src/main/java/net/md_5/bungee/api/plugin/PluginManager.java b/api/src/main/java/net/md_5/bungee/api/plugin/PluginManager.java
index 1ba5b249..f858e281 100644
--- a/api/src/main/java/net/md_5/bungee/api/plugin/PluginManager.java
+++ b/api/src/main/java/net/md_5/bungee/api/plugin/PluginManager.java
@@ -60,7 +60,7 @@ public final class PluginManager
     private final Map<String, Plugin> plugins = new LinkedHashMap<>();
     private final MutableGraph<String> dependencyGraph = GraphBuilder.directed().build();
     private final LibraryLoader libraryLoader;
-    private final Map<String, Command> commandMap = new HashMap<>();
+    private final Map<String, Command> commandMap = new java.util.concurrent.ConcurrentHashMap<>(); // Waterfall - thread safe
     private Map<String, PluginDescription> toLoad = new HashMap<>();
     private final Multimap<Plugin, Command> commandsByPlugin = ArrayListMultimap.create();
     private final Multimap<Plugin, Listener> listenersByPlugin = ArrayListMultimap.create();
@@ -99,12 +99,14 @@ public final class PluginManager
      */
     public void registerCommand(Plugin plugin, Command command)
     {
+        synchronized ( commandsByPlugin ) { // Waterfall - synchronize mutation
         commandMap.put( command.getName().toLowerCase( Locale.ROOT ), command );
         for ( String alias : command.getAliases() )
         {
             commandMap.put( alias.toLowerCase( Locale.ROOT ), command );
         }
         commandsByPlugin.put( plugin, command );
+        } // Waterfall
     }
 
     /**
@@ -114,8 +116,12 @@ public final class PluginManager
      */
     public void unregisterCommand(Command command)
     {
-        while ( commandMap.values().remove( command ) );
-        commandsByPlugin.values().remove( command );
+        // Waterfall start - synchronize mutation
+        synchronized ( commandsByPlugin ) {
+            while ( commandMap.values().remove( command ) );
+            commandsByPlugin.values().remove( command );
+        }
+        // Waterfall end
     }
 
     /**
@@ -125,12 +131,14 @@ public final class PluginManager
      */
     public void unregisterCommands(Plugin plugin)
     {
+        synchronized ( commandsByPlugin ) { // Waterfall - synchronize mutation
         for ( Iterator<Command> it = commandsByPlugin.get( plugin ).iterator(); it.hasNext(); )
         {
             Command command = it.next();
             while ( commandMap.values().remove( command ) );
             it.remove();
         }
+        } // Waterfall
     }
 
     private Command getCommandIfEnabled(String commandName, CommandSender sender)
@@ -278,7 +286,7 @@ public final class PluginManager
      */
     public Collection<Plugin> getPlugins()
     {
-        return plugins.values();
+        synchronized ( plugins ) { return new java.util.ArrayList<>( plugins.values() ); } // Waterfall - synchronize
     }
 
     /**
@@ -289,7 +297,7 @@ public final class PluginManager
      */
     public Plugin getPlugin(String name)
     {
-        return plugins.get( name );
+        synchronized ( plugins ) { return plugins.get( name ); } // Waterfall - synchronize
     }
 
     public void loadPlugins()
@@ -395,7 +403,7 @@ public final class PluginManager
                 Class<?> main = loader.loadClass( plugin.getMain() );
                 Plugin clazz = (Plugin) main.getDeclaredConstructor().newInstance();
 
-                plugins.put( plugin.getName(), clazz );
+                synchronized ( plugins ) { plugins.put( plugin.getName(), clazz ); } // Waterfall - synchronize
                 clazz.onLoad();
                 ProxyServer.getInstance().getLogger().log( Level.INFO, "Loaded plugin {0} version {1} by {2}", new Object[]
                 {
@@ -501,8 +509,13 @@ public final class PluginManager
             Preconditions.checkArgument( !method.isAnnotationPresent( Subscribe.class ),
                     "Listener %s has registered using deprecated subscribe annotation! Please update to @EventHandler.", listener );
         }
-        eventBus.register( listener );
-        listenersByPlugin.put( plugin, listener );
+        // Waterfall start - synchronize mutation
+        synchronized ( listenersByPlugin )
+        {
+            eventBus.register( listener );
+            listenersByPlugin.put( plugin, listener );
+        }
+        // Waterfall end
     }
 
     /**
@@ -512,8 +525,13 @@ public final class PluginManager
      */
     public void unregisterListener(Listener listener)
     {
-        eventBus.unregister( listener );
-        listenersByPlugin.values().remove( listener );
+        // Waterfall start - synchronize mutation
+        synchronized ( listenersByPlugin )
+        {
+            eventBus.unregister( listener );
+            listenersByPlugin.values().remove( listener );
+        }
+        // Waterfall end
     }
 
     /**
@@ -523,11 +541,13 @@ public final class PluginManager
      */
     public void unregisterListeners(Plugin plugin)
     {
+        synchronized ( listenersByPlugin ) { // Waterfall - synchronize mutation
         for ( Iterator<Listener> it = listenersByPlugin.get( plugin ).iterator(); it.hasNext(); )
         {
             eventBus.unregister( it.next() );
             it.remove();
         }
+        } // Waterfall
     }
 
     /**
-- 
2.30.2