Fix patch "Faster redstone torch rapid clock removal" (#2014)

Tux pointed out the patch still has O(n^2) time complexity since
the sublist class in arraylist does not override clear() from
AbstractList, which uses a forward moving iterator to clear
the list.

Resolved by using a peek and poll from ArrayDeque.

This patch also removes the useless WeakHashMap which holds
the list (it mapped world->list) and replaces it with a
field on World.

Spigot-Server-Patches/Add-Heightmap-API.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Add Heightmap API
 
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 235440c651..cae59ed377 100644
+index a1e660767..4caf5d9af 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
@@ -20,7 +20,7 @@ index 235440c651..cae59ed377 100644
  
          if (i >= -30000000 && j >= -30000000 && i < 30000000 && j < 30000000) {
 diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-index ed646bc9db..d2c3ea0dc3 100644
+index b9786909b..cd3814cdd 100644
 --- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 +++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 @@ -0,0 +0,0 @@ public class CraftWorld implements World {

Spigot-Server-Patches/Add-sun-related-API.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Add sun related API
 
 
 diff --git a/src/main/java/net/minecraft/server/EntityInsentient.java b/src/main/java/net/minecraft/server/EntityInsentient.java
-index f1621a9e9d..a8318c88af 100644
+index f1621a9e9..a8318c88a 100644
 --- a/src/main/java/net/minecraft/server/EntityInsentient.java
 +++ b/src/main/java/net/minecraft/server/EntityInsentient.java
 @@ -0,0 +0,0 @@ public abstract class EntityInsentient extends EntityLiving {
@@ -17,7 +17,7 @@ index f1621a9e9d..a8318c88af 100644
          if (this.world.J() && !this.world.isClientSide) {
              float f = this.aE();
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 39d5a8f5e5..2278c7c4ab 100644
+index acd1b856e..8bbcbbf89 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
@@ -29,7 +29,7 @@ index 39d5a8f5e5..2278c7c4ab 100644
          return this.d < 4;
      }
 diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
-index 28c5fd988d..ed646bc9db 100644
+index 583fc6f75..b9786909b 100644
 --- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 +++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
 @@ -0,0 +0,0 @@ public class CraftWorld implements World {
@@ -47,7 +47,7 @@ index 28c5fd988d..ed646bc9db 100644
      public boolean createExplosion(double x, double y, double z, float power) {
          return createExplosion(x, y, z, power, false, true);
 diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftMob.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftMob.java
-index 53c2d154ed..56c233872b 100644
+index 53c2d154e..56c233872 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftMob.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftMob.java
 @@ -0,0 +0,0 @@ public abstract class CraftMob extends CraftLivingEntity implements Mob {

Spigot-Server-Patches/Avoid-Chunk-Lookups-for-Entity-TileEntity-Current-Ch.patch

@@ -10,7 +10,7 @@ to the object directly on the Entity/TileEntity object we can directly grab.
 Use that local value instead to reduce lookups in many hot places.
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index edd8e7810f..5349a3a8bc 100644
+index c388a8261..463353bc7 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
@@ -45,7 +45,7 @@ index edd8e7810f..5349a3a8bc 100644
  
                          chunk.setTileEntity(tileentity1.getPosition(), tileentity1);
 diff --git a/src/main/java/net/minecraft/server/WorldServer.java b/src/main/java/net/minecraft/server/WorldServer.java
-index 38d673d8fe..902aa562cc 100644
+index 0e559133f..1c92cf58a 100644
 --- a/src/main/java/net/minecraft/server/WorldServer.java
 +++ b/src/main/java/net/minecraft/server/WorldServer.java
 @@ -0,0 +0,0 @@ public class WorldServer extends World {

Spigot-Server-Patches/BlockDestroyEvent.patch

@@ -11,7 +11,7 @@ floating in the air.
 This can replace many uses of BlockPhysicsEvent
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 4531adc268..a7333de99a 100644
+index 34d7b9314..ab56086e1 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Faster-redstone-torch-rapid-clock-removal.patch

@@ -6,29 +6,67 @@ Subject: [PATCH] Faster redstone torch rapid clock removal
 Only resize the the redstone torch list once, since resizing arrays / lists is costly
 
 diff --git a/src/main/java/net/minecraft/server/BlockRedstoneTorch.java b/src/main/java/net/minecraft/server/BlockRedstoneTorch.java
-index a99f979ef..a79484e3e 100644
+index a99f979ef..919ba8a14 100644
 --- a/src/main/java/net/minecraft/server/BlockRedstoneTorch.java
 +++ b/src/main/java/net/minecraft/server/BlockRedstoneTorch.java
+@@ -0,0 +0,0 @@ import org.bukkit.event.block.BlockRedstoneEvent; // CraftBukkit
+ public class BlockRedstoneTorch extends BlockTorch {
+ 
+     public static final BlockStateBoolean LIT = BlockProperties.r;
+-    private static final Map<IBlockAccess, List<BlockRedstoneTorch.RedstoneUpdateInfo>> b = new WeakHashMap();
++    // Paper - Move the mapped list to World
+ 
+     protected BlockRedstoneTorch(Block.Info block_info) {
+         super(block_info);
 @@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
+     }
+ 
      public static void a(IBlockData iblockdata, World world, BlockPosition blockposition, Random random, boolean flag) {
-         List list = (List) BlockRedstoneTorch.b.get(world);
+-        List list = (List) BlockRedstoneTorch.b.get(world);
++        // Paper start
++        java.util.ArrayDeque<BlockRedstoneTorch.RedstoneUpdateInfo> redstoneUpdateInfos = world.redstoneUpdateInfos;
  
 -        while (list != null && !list.isEmpty() && world.getTime() - ((BlockRedstoneTorch.RedstoneUpdateInfo) list.get(0)).b > 60L) {
 -            list.remove(0);
-+        // Paper start
++        if (redstoneUpdateInfos != null) {
-+        if (list != null) {
++            BlockRedstoneTorch.RedstoneUpdateInfo curr;
-+            int index = 0;
++            while ((curr = redstoneUpdateInfos.peek()) != null && world.getTime() - curr.getTime() > 60L) {
-+            while (index < list.size() && world.getTime() - ((BlockRedstoneTorch.RedstoneUpdateInfo) list.get(index)).getTime() > 60L) {
++                redstoneUpdateInfos.poll();
-+                index++;
-+            }
-+            if (index > 0) {
-+                list.subList(0, index).clear();
 +            }
          }
 +        // Paper end
  
          // CraftBukkit start
          org.bukkit.plugin.PluginManager manager = world.getServer().getPluginManager();
+@@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
+     }
+ 
+     private static boolean a(World world, BlockPosition blockposition, boolean flag) {
+-        List<BlockRedstoneTorch.RedstoneUpdateInfo> list = (List) BlockRedstoneTorch.b.computeIfAbsent(world, (iblockaccess) -> {
+-            return Lists.newArrayList();
+-        });
++        // Paper start
++        java.util.ArrayDeque<BlockRedstoneTorch.RedstoneUpdateInfo> list = world.redstoneUpdateInfos;
++        if (list == null) {
++            list = world.redstoneUpdateInfos = new java.util.ArrayDeque<>();
++        }
++
+ 
+         if (flag) {
+             list.add(new BlockRedstoneTorch.RedstoneUpdateInfo(blockposition.immutableCopy(), world.getTime()));
+@@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
+ 
+         int i = 0;
+ 
+-        for (int j = 0; j < list.size(); ++j) {
+-            BlockRedstoneTorch.RedstoneUpdateInfo blockredstonetorch_redstoneupdateinfo = (BlockRedstoneTorch.RedstoneUpdateInfo) list.get(j);
+-
++        for (java.util.Iterator<BlockRedstoneTorch.RedstoneUpdateInfo> iterator = list.iterator(); iterator.hasNext();) {
++            BlockRedstoneTorch.RedstoneUpdateInfo blockredstonetorch_redstoneupdateinfo = iterator.next();
++            // Paper end
+             if (blockredstonetorch_redstoneupdateinfo.a.equals(blockposition)) {
+                 ++i;
+                 if (i >= 8) {
 @@ -0,0 +0,0 @@ public class BlockRedstoneTorch extends BlockTorch {
      public static class RedstoneUpdateInfo {
  
@@ -38,4 +76,16 @@ index a99f979ef..a79484e3e 100644
  
          public RedstoneUpdateInfo(BlockPosition blockposition, long i) {
              this.a = blockposition;
+diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
+index de09ed97e..3305e110c 100644
+--- a/src/main/java/net/minecraft/server/World.java
++++ b/src/main/java/net/minecraft/server/World.java
+@@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose
+     private org.spigotmc.TickLimiter tileLimiter;
+     private int tileTickPosition;
+     public final Map<Explosion.CacheKey, Float> explosionDensityCache = new HashMap<>(); // Paper - Optimize explosions
++    public java.util.ArrayDeque<BlockRedstoneTorch.RedstoneUpdateInfo> redstoneUpdateInfos; // Paper - Move from Map in BlockRedstoneTorch to here
+ 
+     public CraftWorld getWorld() {
+         return this.world;
 --

Spigot-Server-Patches/Fix-MC-117075-TE-Unload-Lag-Spike.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Fix MC-117075: TE Unload Lag Spike
 
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 9b9e969f52..ea8a6e557a 100644
+index 8ac081bef..f9413dd68 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Optimize-Captured-TileEntity-Lookup.patch

@@ -10,7 +10,7 @@ Optimize to check if the captured list even has values in it, and also to
 just do a get call since the value can never be null.
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index a7333de99a..235440c651 100644
+index ab56086e1..a1e660767 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Optimize-World.isLoaded-BlockPosition-Z.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Optimize World.isLoaded(BlockPosition)Z
 Reduce method invocations for World.isLoaded(BlockPosition)Z
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 5637c3872..1286703bf 100644
+index 3305e110c..8ac081bef 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Optimize-redstone-algorithm.patch

@@ -19,7 +19,7 @@ Aside from making the obvious class/function renames and obfhelpers I didn't nee
 Just added Bukkit's event system and took a few liberties with dead code and comment misspellings.
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index ad793ffa38..ef882b897f 100644
+index ad793ffa3..ef882b897 100644
 --- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 @@ -0,0 +0,0 @@ public class PaperWorldConfig {
@@ -39,7 +39,7 @@ index ad793ffa38..ef882b897f 100644
  }
 diff --git a/src/main/java/com/destroystokyo/paper/util/RedstoneWireTurbo.java b/src/main/java/com/destroystokyo/paper/util/RedstoneWireTurbo.java
 new file mode 100644
-index 0000000000..cf5661f1c5
+index 000000000..cf5661f1c
 --- /dev/null
 +++ b/src/main/java/com/destroystokyo/paper/util/RedstoneWireTurbo.java
 @@ -0,0 +0,0 @@
@@ -956,7 +956,7 @@ index 0000000000..cf5661f1c5
 +    }
 +}
 diff --git a/src/main/java/net/minecraft/server/BlockRedstoneWire.java b/src/main/java/net/minecraft/server/BlockRedstoneWire.java
-index da903f74b6..aa35e0d061 100644
+index da903f74b..aa35e0d06 100644
 --- a/src/main/java/net/minecraft/server/BlockRedstoneWire.java
 +++ b/src/main/java/net/minecraft/server/BlockRedstoneWire.java
 @@ -0,0 +0,0 @@
@@ -1124,7 +1124,7 @@ index da903f74b6..aa35e0d061 100644
                  c(iblockdata, world, blockposition);
                  world.a(blockposition, false);
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 2278c7c4ab..4531adc268 100644
+index 8bbcbbf89..34d7b9314 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Option-to-prevent-armor-stands-from-doing-entity-loo.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Option to prevent armor stands from doing entity lookups
 
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index 83e54cb904..f06bb3ae19 100644
+index 83e54cb90..f06bb3ae1 100644
 --- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 @@ -0,0 +0,0 @@ public class PaperWorldConfig {
@@ -21,7 +21,7 @@ index 83e54cb904..f06bb3ae19 100644
      private void maxEntityCollision() {
          maxCollisionsPerEntity = getInt( "max-entity-collisions", this.spigotConfig.getInt("max-entity-collisions", 8) );
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index a7e24ed725..5544c4dbf3 100644
+index 8c59ec41c..33f0d1cd8 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Prevent-Mob-AI-Rules-from-Loading-Chunks.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Prevent Mob AI Rules from Loading Chunks
 
 
 diff --git a/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java b/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java
-index ce9318c575..541d97344e 100644
+index ce9318c57..541d97344 100644
 --- a/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java
 +++ b/src/main/java/net/minecraft/server/PathfinderGoalRemoveBlock.java
 @@ -0,0 +0,0 @@ public class PathfinderGoalRemoveBlock extends PathfinderGoalGotoTarget {
@@ -53,7 +53,7 @@ index ce9318c575..541d97344e 100644
          return block == this.g && iworldreader.getType(blockposition.up()).isAir() && iworldreader.getType(blockposition.up(2)).isAir();
      }
 diff --git a/src/main/java/net/minecraft/server/RandomPositionGenerator.java b/src/main/java/net/minecraft/server/RandomPositionGenerator.java
-index 8340d6d25b..78eb1b39cf 100644
+index 8340d6d25..78eb1b39c 100644
 --- a/src/main/java/net/minecraft/server/RandomPositionGenerator.java
 +++ b/src/main/java/net/minecraft/server/RandomPositionGenerator.java
 @@ -0,0 +0,0 @@ public class RandomPositionGenerator {
@@ -74,7 +74,7 @@ index 8340d6d25b..78eb1b39cf 100644
      }
  }
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 5544c4dbf3..39d5a8f5e5 100644
+index 33f0d1cd8..acd1b856e 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/Send-attack-SoundEffects-only-to-players-who-can-see.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Send attack SoundEffects only to players who can see the
 
 
 diff --git a/src/main/java/net/minecraft/server/EntityHuman.java b/src/main/java/net/minecraft/server/EntityHuman.java
-index 0f8100a05e..a30d88af81 100644
+index 0f8100a05..a30d88af8 100644
 --- a/src/main/java/net/minecraft/server/EntityHuman.java
 +++ b/src/main/java/net/minecraft/server/EntityHuman.java
 @@ -0,0 +0,0 @@ public abstract class EntityHuman extends EntityLiving {
@@ -72,7 +72,7 @@ index 0f8100a05e..a30d88af81 100644
                              entity.extinguish();
                          }
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index ea8a6e557a..b3a4b2ea97 100644
+index f9413dd68..8328b0125 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose

Spigot-Server-Patches/use-CB-BlockState-implementations-for-captured-block.patch

@@ -18,7 +18,7 @@ the blockstate that will be valid for restoration, as opposed to dropping
 information on restoration when the event is cancelled.
 
 diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
-index 0389ecadff..dd74f38038 100644
+index 8328b0125..c388a8261 100644
 --- a/src/main/java/net/minecraft/server/World.java
 +++ b/src/main/java/net/minecraft/server/World.java
 @@ -0,0 +0,0 @@ public abstract class World implements IIBlockAccess, GeneratorAccess, AutoClose