From bc6aa0160941037d2193cfb5386289723418492a 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 cc8fdedd5b..5bab0018da 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -467,6 +467,12 @@ 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 enum DuplicateUUIDMode {
         SAFE_REGEN, REGEN, DELETE, NOTHING, WARN
     }
diff --git a/src/main/java/net/minecraft/server/BlockFluids.java b/src/main/java/net/minecraft/server/BlockFluids.java
index 5346eaa348..ec77cbd57e 100644
--- a/src/main/java/net/minecraft/server/BlockFluids.java
+++ b/src/main/java/net/minecraft/server/BlockFluids.java
@@ -78,11 +78,27 @@ public class BlockFluids extends Block implements IFluidSource {
 
     public void onPlace(IBlockData iblockdata, World world, BlockPosition blockposition, IBlockData iblockdata1) {
         if (this.a(world, blockposition, iblockdata)) {
-            world.I().a(blockposition, iblockdata.s().c(), this.a((IWorldReader) world));
+            world.I().a(blockposition, iblockdata.s().c(), 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
+
     public IBlockData updateState(IBlockData iblockdata, EnumDirection enumdirection, IBlockData iblockdata1, GeneratorAccess generatoraccess, BlockPosition blockposition, BlockPosition blockposition1) {
         if (iblockdata.s().d() || iblockdata1.s().d()) {
             generatoraccess.I().a(blockposition, iblockdata.s().c(), this.a((IWorldReader) generatoraccess));
@@ -93,7 +109,7 @@ public class BlockFluids extends Block implements IFluidSource {
 
     public void doPhysics(IBlockData iblockdata, World world, BlockPosition blockposition, Block block, BlockPosition blockposition1) {
         if (this.a(world, blockposition, iblockdata)) {
-            world.I().a(blockposition, iblockdata.s().c(), this.a((IWorldReader) world));
+            world.I().a(blockposition, iblockdata.s().c(), this.getFlowSpeed(world, blockposition)); // Paper
         }
 
     }
-- 
2.19.0