PaperMC/nms-patches/BlockPiston.patch

--- ../work/decompile-8eb82bde//net/minecraft/server/BlockPiston.java	2014-12-05 15:10:57.106252715 +0000
+++ src/main/java/net/minecraft/server/BlockPiston.java	2014-12-05 15:10:54.834252765 +0000
@@ -1,6 +1,16 @@
 package net.minecraft.server;
 
+import java.util.AbstractList;
+import java.util.Collection;
+import java.util.Iterator;
 import java.util.List;
+import java.util.ListIterator;
+
+// CraftBukkit start
+import org.bukkit.craftbukkit.block.CraftBlock;
+import org.bukkit.event.block.BlockPistonRetractEvent;
+import org.bukkit.event.block.BlockPistonExtendEvent;
+// CraftBukkit end
 
 public class BlockPiston extends Block {
 
@@ -52,10 +62,19 @@
         boolean flag = this.b(world, blockposition, enumdirection);
 
         if (flag && !((Boolean) iblockdata.get(BlockPiston.EXTENDED)).booleanValue()) {
-            if ((new PistonExtendsChecker(world, blockposition, enumdirection, true)).a()) {
+            if ((new PistonExtendsChecker(world, blockposition, enumdirection, true)).a()) { 
                 world.playBlockAction(blockposition, this, 0, enumdirection.a());
             }
         } else if (!flag && ((Boolean) iblockdata.get(BlockPiston.EXTENDED)).booleanValue()) {
+            // CraftBukkit start
+            org.bukkit.block.Block block = world.getWorld().getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ());
+            BlockPistonRetractEvent event = new BlockPistonRetractEvent(block, CraftBlock.notchToBlockFace(enumdirection));
+            world.getServer().getPluginManager().callEvent(event);
+
+            if (event.isCancelled()) {
+                return;
+            }
+            // CraftBukkit end
             world.setTypeAndData(blockposition, iblockdata.set(BlockPiston.EXTENDED, Boolean.valueOf(false)), 2);
             world.playBlockAction(blockposition, this, 1, enumdirection.a());
         }
@@ -286,10 +305,40 @@
         if (!pistonextendschecker.a()) {
             return false;
         } else {
+            final org.bukkit.block.Block bblock = world.getWorld().getBlockAt(blockposition.getX(), blockposition.getY(), blockposition.getZ());
+
+            final List moved = pistonextendschecker.getMovedBlocks();
+            final List broken = pistonextendschecker.getBrokenBlocks();
+
+            List<org.bukkit.block.Block> blocks = new AbstractList<org.bukkit.block.Block>() {
+
+                @Override
+                public int size() {
+                    return moved.size() + broken.size();
+                }
+
+                @Override
+                public org.bukkit.block.Block get(int index) {
+                    if (index >= size() || index < 0) {
+                        throw new ArrayIndexOutOfBoundsException(index);
+                    }
+                    BlockPosition pos = (BlockPosition) (index < moved.size() ? moved.get(index) : broken.get(index - moved.size()));
+                    return bblock.getWorld().getBlockAt(pos.getX(), pos.getY(), pos.getZ());
+                }
+            };
+
             int i = list.size() + list1.size();
             Block[] ablock = new Block[i];
             EnumDirection enumdirection1 = flag ? enumdirection : enumdirection.opposite();
 
+            BlockPistonExtendEvent event = new BlockPistonExtendEvent(bblock, blocks, CraftBlock.notchToBlockFace(enumdirection1));
+            world.getServer().getPluginManager().callEvent(event);
+
+            if (event.isCancelled()) {
+                return false;
+            }
+            // CraftBukkit end
+
             int j;
             BlockPosition blockposition1;