Fixes chunk unloading - close #17

sources/src/main/java/io/akarin/server/mixin/core/MixinWorld.java

@@ -0,0 +1,34 @@
+package io.akarin.server.mixin.core;
+
+import java.util.List;
+
+import javax.annotation.Nullable;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import net.minecraft.server.AxisAlignedBB;
+import net.minecraft.server.Entity;
+import net.minecraft.server.World;
+
+/**
+ * Fixes MC-103516(https://bugs.mojang.com/browse/MC-103516)
+ */
+@Mixin(value = World.class, remap = false)
+public abstract class MixinWorld {
+    @Shadow public abstract List<Entity> getEntities(@Nullable Entity entity, AxisAlignedBB box);
+    
+    /**
+     * Returns true if there are no solid, live entities in the specified AxisAlignedBB, excluding the given entity
+     */
+    public boolean a(AxisAlignedBB box, @Nullable Entity target) { // PAIL: checkNoEntityCollision
+        List<Entity> list = this.getEntities(null, box);
+        
+        for (Entity each : list) {
+            if (!each.dead && each.i && each != target && (target == null || !each.x(target))) { // PAIL: preventEntitySpawning - isRidingSameEntity
+                return false;
+            }
+        }
+        return true;
+    }
+}

sources/src/main/java/io/akarin/server/mixin/cps/MixinChunkProviderServer.java

@@ -10,7 +10,9 @@ import org.spongepowered.asm.mixin.Shadow;
 import org.spongepowered.asm.mixin.injection.At;
 import org.spongepowered.asm.mixin.injection.Redirect;
 
+import it.unimi.dsi.fastutil.longs.Long2ObjectMap.Entry;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
+import it.unimi.dsi.fastutil.objects.ObjectIterator;
 import net.minecraft.server.Chunk;
 import net.minecraft.server.ChunkProviderServer;
 import net.minecraft.server.IChunkLoader;
@@ -21,13 +23,10 @@ public abstract class MixinChunkProviderServer {
     @Shadow @Final public WorldServer world;
     @Shadow public Long2ObjectOpenHashMap<Chunk> chunks;
     
-    public int pendingUnloadChunks; // For keeping unload target-size feature
-    
     public void unload(Chunk chunk) {
         if (this.world.worldProvider.c(chunk.locX, chunk.locZ)) {
             // Akarin - avoid using the queue and simply check the unloaded flag during unloads
             // this.unloadQueue.add(Long.valueOf(ChunkCoordIntPair.a(chunk.locX, chunk.locZ)));
-            pendingUnloadChunks++;
             chunk.setShouldUnload(true);
         }
     }
@@ -42,46 +41,41 @@ public abstract class MixinChunkProviderServer {
             long now = System.currentTimeMillis();
             long unloadAfter = world.paperConfig.delayChunkUnloadsBy;
             SlackActivityAccountant activityAccountant = world.getMinecraftServer().slackActivityAccountant;
-            Iterator<Chunk> it = chunks.values().iterator();
+            activityAccountant.startActivity(0.5);
+            ObjectIterator<Entry<Chunk>> it = chunks.long2ObjectEntrySet().fastIterator();
+            int remainingChunks = chunks.size();
+            int targetSize = Math.min(remainingChunks - 100,  (int) (remainingChunks * UNLOAD_QUEUE_RESIZE_FACTOR)); // Paper - Make more aggressive
             
             while (it.hasNext()) {
-                activityAccountant.startActivity(0.5);
+                Entry<Chunk> entry = it.next();
+                Chunk chunk = entry.getValue();
+                if (chunk == null) continue;
                 
-                Chunk chunk = it.next();
-                if (unloadAfter > 0) {
-                    if (chunk.scheduledForUnload != null && now - chunk.scheduledForUnload > unloadAfter) {
-                        chunk.scheduledForUnload = null;
-                        unload(chunk);
+                if (chunk.isUnloading()) {
+                    if (chunk.scheduledForUnload != null) {
+                        if (now - chunk.scheduledForUnload > unloadAfter) {
+                            chunk.scheduledForUnload = null;
+                        } else continue;
                     }
+                    
+                    if (!unloadChunk(chunk, true)) { // Event cancelled
+                        // If a plugin cancelled it, we shouldn't trying unload it for a while
+                        chunk.setShouldUnload(false);
+                        continue;
+                    }
+                    
+                    it.remove(); // Life is strange
+                    if (--remainingChunks <= targetSize || activityAccountant.activityTimeIsExhausted()) break; // more slack since the target size not work as intended
                 }
-                int targetSize = Math.min(pendingUnloadChunks - 100,  (int) (pendingUnloadChunks * UNLOAD_QUEUE_RESIZE_FACTOR)); // Paper - Make more aggressive
-                
-                if (chunk != null && chunk.isUnloading()) {
-                    // If a plugin cancelled it, we shouldn't trying unload it for a while
-                    chunk.setShouldUnload(false); // Paper
-                    
-                    if (!unloadChunk(chunk, true)) continue; // Event cancelled
-                    it.remove();
-                    
-                    if (--pendingUnloadChunks <= targetSize && activityAccountant.activityTimeIsExhausted()) break;
-                }
-                activityAccountant.endActivity();
             }
+            activityAccountant.endActivity();
             this.chunkLoader.b(); // PAIL: chunkTick
         }
         return false;
     }
     
-    @Redirect(method = "unloadChunk", at = @At(
-            value = "INVOKE",
-            target = "it/unimi/dsi/fastutil/longs/Long2ObjectOpenHashMap.remove(J)Ljava/lang/Object;"
-    ))
-    private Object remove(Long2ObjectOpenHashMap<Chunk> chunks, long chunkHash) {
-        return null;
-    }
-    
     @Overwrite
     public String getName() {
-        return "ServerChunkCache: " + chunks.size(); // Akarin - remove unload queue
+        return "ServerChunkCache: " + chunks.size();
     }
 }

sources/src/main/java/io/akarin/server/mixin/lighting/MixinChunk.java

@@ -245,7 +245,7 @@ public abstract class MixinChunk implements IMixinChunk {
             return;
         }
         
-        if (Akari.isPrimaryThread()) {
+        if (Akari.isPrimaryThread(false)) {
             try {
                 lightExecutorService.execute(() -> {
                     this.checkLightAsync(neighborChunks);

sources/src/main/java/io/akarin/server/mixin/lighting/MixinWorld.java

@@ -34,7 +34,7 @@ import net.minecraft.server.IChunkProvider;
 import net.minecraft.server.MinecraftServer;
 import net.minecraft.server.World;
 
-@Mixin(value = World.class, remap = false)
+@Mixin(value = World.class, remap = false, priority = 1001)
 public abstract class MixinWorld {
     @Shadow protected IChunkProvider chunkProvider;
     @Shadow int[] J; // PAIL: lightUpdateBlockList

sources/src/main/java/net/minecraft/server/Chunk.java

@@ -71,7 +71,7 @@ public class Chunk {
             return removed;
         }
     }
-    final PaperLightingQueue.LightingQueue lightingQueue = new PaperLightingQueue.LightingQueue(this);
+    public final PaperLightingQueue.LightingQueue lightingQueue = new PaperLightingQueue.LightingQueue(this); // Akarin - public
     // Paper end
     private volatile boolean done; // Akarin - volatile
     private volatile boolean lit; // Akarin - volatile

sources/src/main/java/net/minecraft/server/PaperLightingQueue.java

@@ -0,0 +1,98 @@
+package net.minecraft.server;
+
+import co.aikar.timings.Timing;
+import it.unimi.dsi.fastutil.objects.ObjectCollection;
+
+import java.util.ArrayDeque;
+
+/**
+ * <b>Akarin Changes Note</b><br>
+ * <br>
+ * 1) Expose private members<br>
+ * @author cakoyo
+ */
+class PaperLightingQueue {
+    private static final long MAX_TIME = (long) (1000000000 / 20 * .95);
+    private static int updatesThisTick;
+
+
+    static void processQueue(long curTime) {
+        updatesThisTick = 0;
+
+        final long startTime = System.nanoTime();
+        final long maxTickTime = MAX_TIME - (startTime - curTime);
+
+        START:
+        for (World world : MinecraftServer.getServer().worlds) {
+            if (!world.paperConfig.queueLightUpdates) {
+                continue;
+            }
+
+            ObjectCollection<Chunk> loadedChunks = ((WorldServer) world).getChunkProviderServer().chunks.values();
+            for (Chunk chunk : loadedChunks.toArray(new Chunk[loadedChunks.size()])) {
+                if (chunk.lightingQueue.processQueue(startTime, maxTickTime)) {
+                    break START;
+                }
+            }
+        }
+    }
+
+    public static class LightingQueue extends ArrayDeque<Runnable> { // Akarin - public
+        final private Chunk chunk;
+
+        LightingQueue(Chunk chunk) {
+            super();
+            this.chunk = chunk;
+        }
+
+        /**
+         * Processes the lighting queue for this chunk
+         *
+         * @param startTime If start Time is 0, we will not limit execution time
+         * @param maxTickTime Maximum time to spend processing lighting updates
+         * @return true to abort processing furthur lighting updates
+         */
+        private boolean processQueue(long startTime, long maxTickTime) {
+            if (this.isEmpty()) {
+                return false;
+            }
+            try (Timing ignored = chunk.world.timings.lightingQueueTimer.startTiming()) {
+                Runnable lightUpdate;
+                while ((lightUpdate = this.poll()) != null) {
+                    lightUpdate.run();
+                    if (startTime > 0 && ++PaperLightingQueue.updatesThisTick % 10 == 0 && PaperLightingQueue.updatesThisTick > 10) {
+                        if (System.nanoTime() - startTime > maxTickTime) {
+                            return true;
+                        }
+                    }
+                }
+            }
+
+            return false;
+        }
+
+        /**
+         * Flushes lighting updates to unload the chunk
+         */
+        public void processUnload() { // Akarin - public
+            if (!chunk.world.paperConfig.queueLightUpdates) {
+                return;
+            }
+            processQueue(0, 0); // No timeout
+
+            final int radius = 1; // TODO: bitflip, why should this ever be 2?
+            for (int x = chunk.locX - radius; x <= chunk.locX + radius; ++x) {
+                for (int z = chunk.locZ - radius; z <= chunk.locZ + radius; ++z) {
+                    if (x == chunk.locX && z == chunk.locZ) {
+                        continue;
+                    }
+
+                    Chunk neighbor = MCUtil.getLoadedChunkWithoutMarkingActive(chunk.world, x, z);
+                    if (neighbor != null) {
+                        neighbor.lightingQueue.processQueue(0, 0); // No timeout
+                    }
+                }
+            }
+        }
+    }
+}

sources/src/main/resources/mixins.akarin.core.json

@@ -13,6 +13,7 @@
         "bootstrap.MetricsBootstrap",
         "bootstrap.MixinRestartCommand",
         
+        "core.MixinWorld",
         "core.MixinMCUtil",
         "core.MixinPlayerList",
         "core.MixinCommandBan",