Cleanup resource mount reloading

- Subscribe to the "on add reload listener" event, otherwise we don't
   get reloads beyond the first one! This means we no longer need to
   cast the resource manager to a reloadable one.
 - Change the mount cache so it's keyed on path, rather than "path ✕
   manager".
 - Update the reload listener just to use the mount cache, rather than
   having its own separate list. I really don't understand what I was
   thinking before.

src/main/java/dan200/computercraft/ComputerCraftAPIImpl.java

@@ -28,6 +28,7 @@ import dan200.computercraft.shared.peripheral.modem.wireless.WirelessNetwork;
 import dan200.computercraft.shared.util.IDAssigner;
 import dan200.computercraft.shared.wired.WiredNode;
 import net.minecraft.resources.IReloadableResourceManager;
+import net.minecraft.resources.IResourceManager;
 import net.minecraft.tileentity.TileEntity;
 import net.minecraft.util.Direction;
 import net.minecraft.util.ResourceLocation;
@@ -101,7 +102,7 @@ public final class ComputerCraftAPIImpl implements IComputerCraftAPI
     @Override
     public IMount createResourceMount( @Nonnull String domain, @Nonnull String subPath )
     {
-        IReloadableResourceManager manager = (IReloadableResourceManager) ServerLifecycleHooks.getCurrentServer().getDataPackRegistries().getResourceManager();
+        IResourceManager manager = ServerLifecycleHooks.getCurrentServer().getDataPackRegistries().getResourceManager();
         ResourceMount mount = ResourceMount.get( domain, subPath, manager );
         return mount.exists( "" ) ? mount : null;
     }

src/main/java/dan200/computercraft/core/filesystem/ResourceMount.java

@@ -7,19 +7,17 @@ package dan200.computercraft.core.filesystem;
 
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
-import com.google.common.collect.MapMaker;
 import com.google.common.io.ByteStreams;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.api.filesystem.IMount;
 import dan200.computercraft.core.apis.handles.ArrayByteChannel;
 import dan200.computercraft.shared.util.IoUtil;
-import net.minecraft.resources.IReloadableResourceManager;
+import net.minecraft.client.resources.ReloadListener;
+import net.minecraft.profiler.IProfiler;
 import net.minecraft.resources.IResource;
 import net.minecraft.resources.IResourceManager;
 import net.minecraft.util.ResourceLocation;
 import net.minecraft.util.ResourceLocationException;
-import net.minecraftforge.resource.IResourceType;
-import net.minecraftforge.resource.ISelectiveResourceReloadListener;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -28,9 +26,10 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
-import java.util.*;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 import java.util.concurrent.TimeUnit;
-import java.util.function.Predicate;
 
 public final class ResourceMount implements IMount
 {
@@ -58,50 +57,37 @@ public final class ResourceMount implements IMount
         .<FileEntry, byte[]>weigher( ( k, v ) -> v.length )
         .build();
 
-    private static final MapMaker CACHE_TEMPLATE = new MapMaker().weakValues().concurrencyLevel( 1 );
-
     /**
      * Maintain a cache of currently loaded resource mounts. This cache is invalidated when currentManager changes.
      */
-    private static final Map<IReloadableResourceManager, Map<ResourceLocation, ResourceMount>> MOUNT_CACHE = new WeakHashMap<>( 2 );
+    private static final Map<ResourceLocation, ResourceMount> MOUNT_CACHE = new HashMap<>( 2 );
 
     private final String namespace;
     private final String subPath;
-    private final IReloadableResourceManager manager;
+    private IResourceManager manager;
 
     @Nullable
     private FileEntry root;
 
-    public static ResourceMount get( String namespace, String subPath, IReloadableResourceManager manager )
+    public static ResourceMount get( String namespace, String subPath, IResourceManager manager )
     {
-        Map<ResourceLocation, ResourceMount> cache;
-
+        ResourceLocation path = new ResourceLocation( namespace, subPath );
         synchronized( MOUNT_CACHE )
         {
-            cache = MOUNT_CACHE.get( manager );
-            if( cache == null ) MOUNT_CACHE.put( manager, cache = CACHE_TEMPLATE.makeMap() );
-        }
-
-        ResourceLocation path = new ResourceLocation( namespace, subPath );
-        synchronized( cache )
-        {
-            ResourceMount mount = cache.get( path );
-            if( mount == null ) cache.put( path, mount = new ResourceMount( namespace, subPath, manager ) );
+            ResourceMount mount = MOUNT_CACHE.get( path );
+            if( mount == null ) MOUNT_CACHE.put( path, mount = new ResourceMount( namespace, subPath, manager ) );
             return mount;
         }
     }
 
-    private ResourceMount( String namespace, String subPath, IReloadableResourceManager manager )
+    private ResourceMount( String namespace, String subPath, IResourceManager manager )
     {
         this.namespace = namespace;
         this.subPath = subPath;
-        this.manager = manager;
-
-        Listener.INSTANCE.add( manager, this );
-        if( root == null ) load();
+        load( manager );
     }
 
-    private void load()
+    private void load( IResourceManager manager )
     {
         boolean hasAny = false;
         String existingNamespace = null;
@@ -118,6 +104,7 @@ public final class ResourceMount implements IMount
             hasAny = true;
         }
 
+        this.manager = manager;
         root = hasAny ? newRoot : null;
 
         if( !hasAny )
@@ -293,35 +280,30 @@ public final class ResourceMount implements IMount
     }
 
     /**
-     * A {@link ISelectiveResourceReloadListener} which reloads any associated mounts.
-     *
-     * While people should really be keeping a permanent reference to this, some people construct it every
-     * method call, so let's make this as small as possible.
+     * A {@link ReloadListener} which reloads any associated mounts and correctly updates the resource manager they
+     * point to.
      */
-    static class Listener implements ISelectiveResourceReloadListener
+    public static final ReloadListener<Void> RELOAD_LISTENER = new ReloadListener<Void>()
     {
-        private static final Listener INSTANCE = new Listener();
-
-        private final Set<ResourceMount> mounts = Collections.newSetFromMap( new WeakHashMap<>() );
-        private final Set<IReloadableResourceManager> managers = Collections.newSetFromMap( new WeakHashMap<>() );
-
+        @Nonnull
         @Override
-        public void onResourceManagerReload( @Nonnull IResourceManager manager )
+        protected Void prepare( @Nonnull IResourceManager manager, @Nonnull IProfiler profiler )
         {
-            // FIXME: Remove this. We need this patch in order to prevent trying to load ReloadRequirements.
-            onResourceManagerReload( manager, x -> true );
+            profiler.push( "Reloading ComputerCraft mounts" );
+            try
+            {
+                for( ResourceMount mount : MOUNT_CACHE.values() ) mount.load( manager );
+            }
+            finally
+            {
+                profiler.pop();
+            }
+            return null;
         }
 
         @Override
-        public synchronized void onResourceManagerReload( @Nonnull IResourceManager manager, @Nonnull Predicate<IResourceType> predicate )
+        protected void apply( @Nonnull Void result, @Nonnull IResourceManager manager, @Nonnull IProfiler profiler )
         {
-            for( ResourceMount mount : mounts ) mount.load();
-        }
-
-        synchronized void add( IReloadableResourceManager manager, ResourceMount mount )
-        {
-            if( managers.add( manager ) ) manager.registerReloadListener( this );
-            mounts.add( mount );
-        }
         }
+    };
 }

src/main/java/dan200/computercraft/shared/CommonHooks.java

@@ -8,6 +8,7 @@ package dan200.computercraft.shared;
 import dan200.computercraft.ComputerCraft;
 import dan200.computercraft.core.apis.http.NetworkUtils;
 import dan200.computercraft.core.computer.MainThread;
+import dan200.computercraft.core.filesystem.ResourceMount;
 import dan200.computercraft.core.tracking.ComputerMBean;
 import dan200.computercraft.core.tracking.Tracking;
 import dan200.computercraft.shared.command.CommandComputerCraft;
@@ -23,6 +24,7 @@ import net.minecraft.loot.TableLootEntry;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.dedicated.DedicatedServer;
 import net.minecraft.util.ResourceLocation;
+import net.minecraftforge.event.AddReloadListenerEvent;
 import net.minecraftforge.event.LootTableLoadEvent;
 import net.minecraftforge.event.RegisterCommandsEvent;
 import net.minecraftforge.event.TickEvent;
@@ -138,4 +140,10 @@ public final class CommonHooks
             .name( "computercraft_treasure" )
             .build() );
     }
+
+    @SubscribeEvent
+    public static void onAddReloadListeners( AddReloadListenerEvent event )
+    {
+        event.addListener( ResourceMount.RELOAD_LISTENER );
+    }
 }