From f8a365cb2aec0ff53a6fea230a9fdde2b29aae6f Mon Sep 17 00:00:00 2001
From: Byteflux <byte@byteflux.net>
Date: Wed, 8 Aug 2018 16:33:21 -0600
Subject: [PATCH] Configurable speed for water flowing over lava


diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 2b5402b009..2c27be63ea 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -401,6 +401,12 @@ public class PaperWorldConfig {
         }
     }
 
+    public int waterOverLavaFlowSpeed;
+    private void waterOverLavaFlowSpeed() {
+        waterOverLavaFlowSpeed = getInt("water-over-lava-flow-speed", 5);
+        log("Water over lava flow speed: " + waterOverLavaFlowSpeed);
+    }
+
     public boolean armorStandTick = true;
     private void armorStandTick() {
         this.armorStandTick = this.getBoolean("armor-stands-tick", this.armorStandTick);
diff --git a/src/main/java/net/minecraft/server/BlockFluids.java b/src/main/java/net/minecraft/server/BlockFluids.java
index 44e00339f2..b4616f259e 100644
--- a/src/main/java/net/minecraft/server/BlockFluids.java
+++ b/src/main/java/net/minecraft/server/BlockFluids.java
@@ -70,11 +70,27 @@ public class BlockFluids extends Block implements IFluidSource {
     @Override
     public void onPlace(IBlockData iblockdata, World world, BlockPosition blockposition, IBlockData iblockdata1, boolean flag) {
         if (this.a(world, blockposition, iblockdata)) {
-            world.getFluidTickList().a(blockposition, iblockdata.p().getType(), this.a((IWorldReader) world));
+            world.getFluidTickList().a(blockposition, iblockdata.p().getType(), this.getFlowSpeed(world, blockposition)); // Paper
         }
 
     }
 
+    // Paper start - Get flow speed. Throttle if its water and flowing adjacent to lava
+    public int getFlowSpeed(World world, BlockPosition blockposition) {
+        if (this.material == Material.WATER) {
+            if (
+                world.getMaterialIfLoaded(blockposition.north(1)) == Material.LAVA ||
+                world.getMaterialIfLoaded(blockposition.south(1)) == Material.LAVA ||
+                world.getMaterialIfLoaded(blockposition.west(1)) == Material.LAVA ||
+                world.getMaterialIfLoaded(blockposition.east(1)) == Material.LAVA
+            ) {
+                return world.paperConfig.waterOverLavaFlowSpeed;
+            }
+        }
+        return this.a(world);
+    }
+    // Paper end
+
     @Override
     public IBlockData updateState(IBlockData iblockdata, EnumDirection enumdirection, IBlockData iblockdata1, GeneratorAccess generatoraccess, BlockPosition blockposition, BlockPosition blockposition1) {
         if (iblockdata.p().isSource() || iblockdata1.p().isSource()) {
@@ -87,7 +103,7 @@ public class BlockFluids extends Block implements IFluidSource {
     @Override
     public void doPhysics(IBlockData iblockdata, World world, BlockPosition blockposition, Block block, BlockPosition blockposition1, boolean flag) {
         if (this.a(world, blockposition, iblockdata)) {
-            world.getFluidTickList().a(blockposition, iblockdata.p().getType(), this.a((IWorldReader) world));
+            world.getFluidTickList().a(blockposition, iblockdata.p().getType(), this.getFlowSpeed(world, blockposition)); // Paper
         }
 
     }
-- 
2.21.0