Adds LiquidFlow exploit handling

“hand” merged from HCF. Adds option in conf.json that defaults to false
which if enabled will prevent liquid from flowing between into other
factions if it shouldn’t.

src/main/java/com/massivecraft/factions/Conf.java

@@ -102,6 +102,7 @@ public class Conf {
     public static boolean handleExploitEnderPearlClipping = true;
     public static boolean handleExploitInteractionSpam = true;
     public static boolean handleExploitTNTWaterlog = false;
+    public static boolean handleExploitLiquidFlow = false;
 
     public static boolean homesEnabled = true;
     public static boolean homesMustBeInClaimedTerritory = true;

src/main/java/com/massivecraft/factions/listeners/FactionsBlockListener.java

@@ -38,6 +38,30 @@ public class FactionsBlockListener implements Listener {
         }
     }
 
+    @EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
+    public void onBlockFromTo(BlockFromToEvent event) {
+        if (!Conf.handleExploitLiquidFlow) {
+            return;
+        }
+        if (event.getBlock().isLiquid()) {
+            if (event.getToBlock().isEmpty()) {
+                Faction from = Board.getInstance().getFactionAt(new FLocation(event.getBlock()));
+                Faction to = Board.getInstance().getFactionAt(new FLocation(event.getToBlock()));
+                if (from == to) {
+                    // not concerned with inter-faction events
+                    return;
+                }
+                // from faction != to faction
+                if (to.isNormal()) {
+                    if (from.isNormal() && from.getRelationTo(to).isAlly()) {
+                        return;
+                    }
+                    event.setCancelled(true);
+                }
+            }
+        }
+    }
+
     @EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
     public void onBlockBreak(BlockBreakEvent event) {
         if (!playerCanBuildDestroyBlock(event.getPlayer(), event.getBlock().getLocation(), "destroy", false)) {