From 8b5a89bf12f67a76b610e908c4536d5a53646c7c Mon Sep 17 00:00:00 2001
From: Virizion <9b717b9d4e5f09e89fa3@gmail.com>
Date: Mon, 7 Jan 2019 01:40:48 -0500
Subject: [PATCH] #2576: Allow plugins to register multiple intents for async
 events

---
 .../net/md_5/bungee/api/event/AsyncEvent.java | 29 ++++++++++++-------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/api/src/main/java/net/md_5/bungee/api/event/AsyncEvent.java b/api/src/main/java/net/md_5/bungee/api/event/AsyncEvent.java
index 050da403..63f34307 100644
--- a/api/src/main/java/net/md_5/bungee/api/event/AsyncEvent.java
+++ b/api/src/main/java/net/md_5/bungee/api/event/AsyncEvent.java
@@ -1,8 +1,7 @@
 package net.md_5.bungee.api.event;
 
 import com.google.common.base.Preconditions;
-import java.util.Collections;
-import java.util.Set;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -25,7 +24,7 @@ public class AsyncEvent<T> extends Event
 {
 
     private final Callback<T> done;
-    private final Set<Plugin> intents = Collections.newSetFromMap( new ConcurrentHashMap<Plugin, Boolean>() );
+    private final Map<Plugin, AtomicInteger> intents = new ConcurrentHashMap<Plugin, AtomicInteger>();
     private final AtomicBoolean fired = new AtomicBoolean();
     private final AtomicInteger latch = new AtomicInteger();
 
@@ -43,30 +42,40 @@ public class AsyncEvent<T> extends Event
     /**
      * Register an intent that this plugin will continue to perform work on a
      * background task, and wishes to let the event proceed once the registered
-     * background task has completed.
+     * background task has completed. Multiple intents can be registered by a
+     * plugin, but the plugin must complete the same amount of intents for the
+     * event to proceed.
      *
      * @param plugin the plugin registering this intent
      */
     public void registerIntent(Plugin plugin)
     {
         Preconditions.checkState( !fired.get(), "Event %s has already been fired", this );
-        Preconditions.checkState( !intents.contains( plugin ), "Plugin %s already registered intent for event %s", plugin, this );
 
-        intents.add( plugin );
+        AtomicInteger intentCount = intents.get( plugin );
+        if ( intentCount == null )
+        {
+            intents.put( plugin, new AtomicInteger( 1 ) );
+        } else
+        {
+            intentCount.incrementAndGet();
+        }
         latch.incrementAndGet();
     }
 
     /**
-     * Notifies this event that this plugin has done all its required processing
-     * and wishes to let the event proceed.
+     * Notifies this event that this plugin has completed an intent and wishes
+     * to let the event proceed once all intents have been completed.
      *
      * @param plugin a plugin which has an intent registered for this event
      */
     @SuppressWarnings("unchecked")
     public void completeIntent(Plugin plugin)
     {
-        Preconditions.checkState( intents.contains( plugin ), "Plugin %s has not registered intent for event %s", plugin, this );
-        intents.remove( plugin );
+        AtomicInteger intentCount = intents.get( plugin );
+        Preconditions.checkState( intentCount != null && intentCount.get() > 0, "Plugin %s has not registered intents for event %s", plugin, this );
+
+        intentCount.decrementAndGet();
         if ( fired.get() )
         {
             if ( latch.decrementAndGet() == 0 )