Upstream Paper

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

@@ -0,0 +1,98 @@
+package net.minecraft.server;
+
+import co.aikar.timings.Timing;
+import com.destroystokyo.paper.PaperConfig;
+import it.unimi.dsi.fastutil.objects.ObjectCollection;
+
+import java.util.ArrayDeque;
+
+class PaperLightingQueue {
+    private static final long MAX_TIME = (long) (1000000 * (50 + PaperConfig.maxTickMsLostLightQueue));
+
+    static void processQueue(long curTime) {
+        final long startTime = System.nanoTime();
+        final long maxTickTime = MAX_TIME - (startTime - curTime);
+
+        if (maxTickTime <= 0) {
+            return;
+        }
+
+        START:
+        for (World world : MinecraftServer.getServer().getWorlds()) {
+            if (!world.paperConfig.queueLightUpdates) {
+                continue;
+            }
+
+            ObjectCollection<Chunk> loadedChunks = ((WorldServer) world).getChunkProvider().chunks.values();
+            for (Chunk chunk : loadedChunks.toArray(new Chunk[0])) {
+                if (chunk.lightingQueue.processQueue(startTime, maxTickTime)) {
+                    break START;
+                }
+            }
+        }
+    }
+
+    static class LightingQueue extends ArrayDeque<Runnable> {
+        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;
+            }
+            if (isOutOfTime(maxTickTime, startTime)) {
+                return true;
+            }
+            try (Timing ignored = chunk.world.timings.lightingQueueTimer.startTiming()) {
+                Runnable lightUpdate;
+                while ((lightUpdate = this.poll()) != null) {
+                    lightUpdate.run();
+                    if (isOutOfTime(maxTickTime, startTime)) {
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+
+        /**
+         * Flushes lighting updates to unload the chunk
+         */
+        void processUnload() {
+            if (!chunk.world.paperConfig.queueLightUpdates) {
+                return;
+            }
+            processQueue(0, 0); // No timeout
+
+            final int radius = 1;
+            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 = chunk.world.getChunkIfLoaded(x, z);
+                    if (neighbor != null) {
+                        neighbor.lightingQueue.processQueue(0, 0); // No timeout
+                    }
+                }
+            }
+        }
+    }
+
+    private static boolean isOutOfTime(long maxTickTime, long startTime) {
+        return startTime > 0 && System.nanoTime() - startTime > maxTickTime;
+    }
+}