Correct a missing noEntryValue in Spigot.

Again.

ProtocolLib/src/main/java/com/comphenix/protocol/injector/netty/NettyProtocolInjector.java

@@ -35,7 +35,6 @@ import com.comphenix.protocol.injector.spigot.AbstractPacketInjector;
 import com.comphenix.protocol.injector.spigot.AbstractPlayerHandler;
 import com.comphenix.protocol.reflect.FuzzyReflection;
 import com.comphenix.protocol.reflect.VolatileField;
-import com.comphenix.protocol.reflect.accessors.FieldAccessor;
 import com.comphenix.protocol.utility.MinecraftReflection;
 import com.google.common.collect.Lists;
 

ProtocolLib/src/main/java/com/comphenix/protocol/injector/packet/LegacyPacketRegistry.java

@@ -20,6 +20,7 @@ import com.comphenix.protocol.reflect.fuzzy.FuzzyMethodContract;
 import com.comphenix.protocol.utility.MinecraftReflection;
 import com.comphenix.protocol.wrappers.TroveWrapper;
 
+import com.google.common.base.Function;
 import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
@@ -164,18 +165,16 @@ class LegacyPacketRegistry {
 				FuzzyFieldContract.newBuilder().typeMatches(mapLike).build());
 		Object troveMap = FieldUtils.readStaticField(packetsField, true);
 		
-		// Check for stupid no_entry_values
+		// Fix incorrect no entry values
-		try {
+		TroveWrapper.transformNoEntryValue(troveMap, new Function<Integer, Integer>() {
-			Field field = FieldUtils.getField(troveMap.getClass(), "no_entry_value", true);
+			public Integer apply(Integer value) {
-			Integer value = (Integer) FieldUtils.readField(field, troveMap, true);
+				if (value >= 0 && value < 256) {
-			
+					// Someone forgot to set the no entry value. Let's help them.
-			if (value >= 0 && value < 256) {
+					return -1;
-				// Someone forgot to set the no entry value. Let's help them.
+				}
-				FieldUtils.writeField(field, troveMap, -1);
+				return value;
 			}
-		} catch (IllegalArgumentException e) {
+		});
-			throw new CannotCorrectTroveMapException(e);
-		}
 		
 		// We'll assume this a Trove map
 		return TroveWrapper.getDecoratedMap(troveMap);
@@ -333,12 +332,4 @@ class LegacyPacketRegistry {
 			return packetCount;
 		}
 	}
-	
-	public static class CannotCorrectTroveMapException extends RuntimeException {
-		private static final long serialVersionUID = 1L;
-
-		private CannotCorrectTroveMapException(Throwable inner) {
-			super("Cannot correct trove map.", inner);
-		}
-	}
 }

ProtocolLib/src/main/java/com/comphenix/protocol/injector/packet/PacketRegistry.java

@@ -28,10 +28,10 @@ import com.comphenix.protocol.ProtocolLibrary;
 import com.comphenix.protocol.error.Report;
 import com.comphenix.protocol.error.ReportType;
 import com.comphenix.protocol.injector.netty.NettyProtocolRegistry;
-import com.comphenix.protocol.injector.packet.LegacyPacketRegistry.CannotCorrectTroveMapException;
 import com.comphenix.protocol.injector.packet.LegacyPacketRegistry.InsufficientPacketsException;
 import com.comphenix.protocol.reflect.FieldAccessException;
 import com.comphenix.protocol.utility.MinecraftReflection;
+import com.comphenix.protocol.wrappers.TroveWrapper.CannotFindTroveNoEntryValue;
 import com.google.common.base.Function;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
@@ -119,7 +119,7 @@ public class PacketRegistry {
 						PacketRegistry.class, Report.newBuilder(REPORT_INSUFFICIENT_SERVER_PACKETS).messageParam(e.getPacketCount())
 					);
 				}
-			} catch (CannotCorrectTroveMapException e) {
+			} catch (CannotFindTroveNoEntryValue e) {
 				ProtocolLibrary.getErrorReporter().reportWarning(PacketRegistry.class, 
 					Report.newBuilder(REPORT_CANNOT_CORRECT_TROVE_MAP).error(e.getCause()));
 			}

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/TroveWrapper.java

@@ -10,11 +10,13 @@ import java.util.Set;
 import javax.annotation.Nonnull;
 
 import com.comphenix.protocol.reflect.FieldAccessException;
+import com.comphenix.protocol.reflect.FieldUtils;
 import com.comphenix.protocol.reflect.accessors.FieldAccessor;
 import com.comphenix.protocol.reflect.accessors.ReadOnlyFieldAccessor;
 import com.comphenix.protocol.reflect.fuzzy.AbstractFuzzyMatcher;
 import com.comphenix.protocol.reflect.fuzzy.FuzzyMatchers;
 import com.comphenix.protocol.utility.ClassSource;
+import com.google.common.base.Function;
 
 /**
  * Wrap a GNU Trove Collection class with an equivalent Java Collection class.
@@ -38,9 +40,24 @@ public class TroveWrapper {
 	 * @return The read only accessor.
 	 */
 	public static ReadOnlyFieldAccessor wrapMapField(final FieldAccessor accessor) {
+		return wrapMapField(accessor, null);
+	}
+	
+	/**
+	 * Retrieve a read-only field accessor that automatically wraps the underlying Trove instance.
+	 * @param accessor - the accessor.
+	 * @param noEntryTransform - transform the no entry value, or NULL to ignore.
+	 * @return The read only accessor.
+	 */
+	public static ReadOnlyFieldAccessor wrapMapField(final FieldAccessor accessor, final Function<Integer, Integer> noEntryTransform) {
 		return new ReadOnlyFieldAccessor() {
 			public Object get(Object instance) {
-				return getDecoratedMap(accessor.get(instance));
+				Object troveMap = accessor.get(instance);
+				
+				// Apply transform as well
+				if (noEntryTransform != null)
+					TroveWrapper.transformNoEntryValue(troveMap, noEntryTransform);
+				return getDecoratedMap(troveMap);
 			}
 			public Field getField() {
 				return accessor.getField();
@@ -131,6 +148,28 @@ public class TroveWrapper {
 		return getClassSource(clazz) != null;
 	}
 	
+	/**
+	 * Transform the no entry value in the given map.
+	 * @param troveMap - the trove map.
+	 * @param transform - the transform.
+	 */
+	public static void transformNoEntryValue(Object troveMap, Function<Integer, Integer> transform) {
+		// Check for stupid no_entry_values
+		try {
+			Field field = FieldUtils.getField(troveMap.getClass(), "no_entry_value", true);
+			int current = (Integer) FieldUtils.readField(field, troveMap, true);
+			int transformed = transform.apply(current);
+			
+			if (current != transformed) {
+				FieldUtils.writeField(field, troveMap, transformed);
+			}
+		} catch (IllegalArgumentException e) {
+			throw new CannotFindTroveNoEntryValue(e);
+		} catch (IllegalAccessException e) {
+			throw new IllegalStateException("Cannot access reflection.", e);
+		}
+	}
+	
 	/**
 	 * Retrieve the correct class source from the given class.
 	 * @param clazz - the class source.
@@ -189,4 +228,12 @@ public class TroveWrapper {
 		
 		throw new IllegalArgumentException("Cannot find decorator for " + trove + " (" + trove.getClass() + ")");
 	}
+	
+	public static class CannotFindTroveNoEntryValue extends RuntimeException {
+		private static final long serialVersionUID = 1L;
+
+		private CannotFindTroveNoEntryValue(Throwable inner) {
+			super("Cannot correct trove map.", inner);
+		}
+	}
 }

ProtocolLib/src/main/java/com/comphenix/protocol/wrappers/WrappedDataWatcher.java

@@ -598,7 +598,16 @@ public class WrappedDataWatcher extends AbstractWrapper implements Iterable<Wrap
 			
 			if (TroveWrapper.isTroveClass(type)) {
 				// Create a wrapper accessor
-				final ReadOnlyFieldAccessor accessor = TroveWrapper.wrapMapField(Accessors.getFieldAccessor(lookup, true));
+				final ReadOnlyFieldAccessor accessor = TroveWrapper.wrapMapField(
+				  Accessors.getFieldAccessor(lookup, true), new Function<Integer, Integer>() {
+					@Override
+					public Integer apply(@Nullable Integer value) {
+						// Do not use zero for no entry value
+						if (value == 0)
+							return -1;
+						return value;
+					}
+				});
 				
 				if (Modifier.isStatic(lookup.getModifiers())) {
 					TYPE_MAP_ACCESSOR = accessor;