Add method to send fake sign updates to players. Adds BUKKIT-2300

src/main/java/net/minecraft/server/PlayerConnection.java

@@ -1583,12 +1583,7 @@ public class PlayerConnection implements PacketPlayInListener {
                 this.server.getPluginManager().callEvent(event);
 
                 if (!event.isCancelled()) {
-                    for (int l = 0; l < 4; ++l) {
+                    tileentitysign1.lines = org.bukkit.craftbukkit.block.CraftSign.sanitizeLines(event.getLines());
-                        tileentitysign1.lines[l] = event.getLine(l);
-                        if(tileentitysign1.lines[l] == null) {
-                            tileentitysign1.lines[l] = "";
-                        }
-                    }
                     tileentitysign1.isEditable = false;
                 }
                 // System.arraycopy(packetplayinupdatesign.f(), 0, tileentitysign1.lines, 0, 4);

src/main/java/net/minecraft/server/TileEntitySign.java

@@ -30,17 +30,7 @@ public class TileEntitySign extends TileEntity {
     }
 
     public Packet getUpdatePacket() {
-        String[] astring = new String[4];
+        String[] astring = sanitizeLines(this.lines); // CraftBukkit - call sign line sanitizer to limit line length
-
-        // CraftBukkit start - Limit sign text to 15 chars per line
-        for (int i = 0; i < 4; ++i) {
-            astring[i] = this.lines[i];
-
-            if (this.lines[i].length() > 15) {
-                astring[i] = this.lines[i].substring(0, 15);
-            }
-        }
-        // CraftBukkit end
 
         return new PacketPlayOutUpdateSign(this.x, this.y, this.z, astring);
     }
@@ -56,4 +46,18 @@ public class TileEntitySign extends TileEntity {
     public EntityHuman b() {
         return this.k;
     }
+
+    // CraftBukkit start - central method to limit sign text to 15 chars per line
+    public static String[] sanitizeLines(String[] lines) {
+        String[] astring = new String[4];
+        for (int i = 0; i < 4; ++i) {
+            astring[i] = lines[i];
+
+            if (lines[i].length() > 15) {
+                astring[i] = lines[i].substring(0, 15);
+            }
+        }
+        return astring;
+    }
+    // CraftBukkit end
 }

src/main/java/org/bukkit/craftbukkit/block/CraftSign.java

@@ -35,16 +35,24 @@ public class CraftSign extends CraftBlockState implements Sign {
         boolean result = super.update(force, applyPhysics);
 
         if (result) {
-            for(int i = 0; i < 4; i++) {
+            sign.lines = sanitizeLines(lines);
-                if(lines[i] != null) {
-                    sign.lines[i] = lines[i];
-                } else {
-                    sign.lines[i] = "";
-                }
-            }
             sign.update();
         }
 
         return result;
     }
+
+    public static String[] sanitizeLines(String[] lines) {
+        String[] astring = new String[4];
+
+        for (int i = 0; i < 4; i++) {
+            if (i < lines.length && lines[i] != null) {
+                astring[i] = lines[i];
+            } else {
+                astring[i] = "";
+            }
+        }
+
+        return TileEntitySign.sanitizeLines(astring);
+    }
 }

src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java

@@ -31,6 +31,7 @@ import org.bukkit.configuration.serialization.DelegateDeserialization;
 import org.bukkit.conversations.Conversation;
 import org.bukkit.conversations.ConversationAbandonedEvent;
 import org.bukkit.conversations.ManuallyAbandonedConversationCanceller;
+import org.bukkit.craftbukkit.block.CraftSign;
 import org.bukkit.craftbukkit.conversations.ConversationTracker;
 import org.bukkit.craftbukkit.CraftEffect;
 import org.bukkit.craftbukkit.CraftOfflinePlayer;
@@ -368,6 +369,27 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         getHandle().playerConnection.sendPacket(packet);
     }
 
+    @Override
+    public void sendSignChange(Location loc, String[] lines) {
+        if (getHandle().playerConnection == null) {
+            return;
+        }
+
+        if (lines == null) {
+            lines = new String[4];
+        }
+
+        Validate.notNull(loc, "Location can not be null");
+        if (lines.length < 4) {
+            throw new IllegalArgumentException("Must have at least 4 lines");
+        }
+
+        // Limit to 15 chars per line and set null lines to blank
+        String[] astring = CraftSign.sanitizeLines(lines);
+
+        getHandle().playerConnection.sendPacket(new PacketPlayOutUpdateSign(loc.getBlockX(), loc.getBlockY(), loc.getBlockZ(), astring));
+    }
+
     @Override
     public boolean sendChunkChange(Location loc, int sx, int sy, int sz, byte[] data) {
         if (getHandle().playerConnection == null) return false;