Sketch a reflection based provider for IEntityAccessLastPositionAndLook.

Directly following:
* Boat fly check based on VehicleUpdateEvent and fetching last pos.
* Implement a native access based provider for
EntityAccessLastPositionAndLook, after testing the reflection based one.

Likely following:
* Implement the same fly checks based on PlayerMoveEvent for horses and
pigs too, for the case server-side fly checking is disabled.
* Configurability for individual types of enbtities, at least a flag for
activation.
* Not sure if a fall-back to VehicleMoveEvent should be kept, setup
shouldn't be all too complicated.

NCPCommons/src/main/java/fr/neatmonster/nocheatplus/utilities/Validate.java

@@ -0,0 +1,26 @@
+package fr.neatmonster.nocheatplus.utilities;
+
+/**
+ * Simple parameter/thing validation.
+ * 
+ * @author asofold
+ *
+ */
+public class Validate {
+
+    /**
+     * Throw a NullPointerException if any given object is null.
+     * 
+     * @param objects
+     * @throws NullPointerException
+     *             If any object is null.
+     */
+    public static void validateNotNull(final Object...objects) {
+        for (int i = 0; i < objects.length; i++) {
+            if (objects[i] == null) {
+                throw new NullPointerException("Object at index " + i + " is null.");
+            }
+        }
+    }
+
+}

NCPCompatBukkit/src/main/java/fr/neatmonster/nocheatplus/compat/cbreflect/reflect/ReflectBlockSix.java

@@ -14,7 +14,14 @@ import fr.neatmonster.nocheatplus.logging.Streams;
 import fr.neatmonster.nocheatplus.utilities.ReflectionUtil;
 import fr.neatmonster.nocheatplus.utilities.StringUtil;
 
-public class ReflectBlock {
+/**
+ * Classic Block with 6 consecutive getter methods for the shape and
+ * updateShape.
+ * 
+ * @author asofold
+ *
+ */
+public class ReflectBlockSix {
     
     /** Obfuscated nms names, allowing to find the order in the source code under certain circumstances. */
     private static final List<String> possibleNames = new ArrayList<String>();
@@ -41,7 +48,7 @@ public class ReflectBlock {
     public final Method nmsGetMinZ;
     public final Method nmsGetMaxZ;
 
-    public ReflectBlock(ReflectBase base, ReflectBlockPosition blockPosition) throws ClassNotFoundException {
+    public ReflectBlockSix(ReflectBase base, ReflectBlockPosition blockPosition) throws ClassNotFoundException {
         final Class<?> clazz = Class.forName(base.nmsPackageName + ".Block");
         // byID (static)
         nmsGetById = ReflectionUtil.getMethod(clazz, "getById", int.class);

NCPCompatBukkit/src/main/java/fr/neatmonster/nocheatplus/compat/cbreflect/reflect/ReflectEntityDamage.java

@@ -3,6 +3,8 @@ package fr.neatmonster.nocheatplus.compat.cbreflect.reflect;
 import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 
+import org.bukkit.entity.Entity;
+
 import fr.neatmonster.nocheatplus.utilities.ReflectionUtil;
 
 /**
@@ -10,29 +12,25 @@ import fr.neatmonster.nocheatplus.utilities.ReflectionUtil;
  * @author asofold
  *
  */
-public class ReflectEntity {
+public class ReflectEntityDamage extends ReflectGetHandleBase<Entity> {
 
     public final Field nmsDead;
 
-    public final Method obcGetHandle;
-    
     public final Method nmsDamageEntity;
-    
+
     public final boolean nmsDamageEntityInt;
 
-    public ReflectEntity(ReflectBase base, ReflectDamageSource damageSource) throws ClassNotFoundException {
+    public ReflectEntityDamage(ReflectBase base, ReflectDamageSource damageSource) throws ClassNotFoundException {
         this(base, damageSource, Class.forName(base.obcPackageName + ".entity.CraftEntity"), Class.forName(base.nmsPackageName + ".Entity"));
-
     }
 
-    public ReflectEntity(ReflectBase base, ReflectDamageSource damageSource, Class<?> obcClass, Class<?> nmsClass) throws ClassNotFoundException {
-        // getHandle
-        obcGetHandle = ReflectionUtil.getMethodNoArgs(obcClass, "getHandle");
-        // TODO: Consider throw in case of getHandle missing.
-        
+    public ReflectEntityDamage(ReflectBase base, ReflectDamageSource damageSource, Class<?> obcClass, Class<?> nmsClass) throws ClassNotFoundException {
+        // base
+        super(base, obcClass, nmsClass);
+
         // dead
         nmsDead = ReflectionUtil.getField(nmsClass, "dead", boolean.class);
-        
+
         // damageEntity(...)
         nmsDamageEntity = ReflectionUtil.getMethod(nmsClass, "damageEntity", 
                 new Class<?>[]{damageSource.nmsClass, float.class}, new Class<?>[]{damageSource.nmsClass, int.class});
@@ -43,4 +41,9 @@ public class ReflectEntity {
         }
     }
 
+    @Override
+    protected void fail() {
+        // Unused.
+    }
+
 }

NCPCompatBukkit/src/main/java/fr/neatmonster/nocheatplus/compat/cbreflect/reflect/ReflectEntityLastPositionAndLook.java

@@ -0,0 +1,68 @@
+package fr.neatmonster.nocheatplus.compat.cbreflect.reflect;
+
+import java.lang.reflect.Field;
+
+import org.bukkit.entity.Entity;
+
+import fr.neatmonster.nocheatplus.NCPAPIProvider;
+import fr.neatmonster.nocheatplus.components.location.IEntityAccessLastPositionAndLook;
+import fr.neatmonster.nocheatplus.components.location.ISetPositionWithLook;
+import fr.neatmonster.nocheatplus.logging.Streams;
+import fr.neatmonster.nocheatplus.utilities.ReflectionUtil;
+import fr.neatmonster.nocheatplus.utilities.Validate;
+
+/**
+ * Access last position and look. This must be able to work independently of
+ * MCAccess. Should be registered as generic instance for
+ * IEntityAccessLastPositionAndLook.
+ * 
+ * @author asofold
+ *
+ */
+public class ReflectEntityLastPositionAndLook extends ReflectGetHandleBase<Entity> implements IEntityAccessLastPositionAndLook {
+
+    public final Field lastX, lastY, lastZ, lastYaw, lastPitch;
+
+    public ReflectEntityLastPositionAndLook() throws ClassNotFoundException {
+        this(new ReflectBase());
+    }
+
+    public ReflectEntityLastPositionAndLook(ReflectBase base) throws ClassNotFoundException {
+        this(base, Class.forName(base.obcPackageName + ".entity.CraftEntity"), Class.forName(base.nmsPackageName + ".Entity"));
+    }
+
+    public ReflectEntityLastPositionAndLook(ReflectBase base, Class<?> obcClass, Class<?> nmsClass) throws ClassNotFoundException, NoSuchFieldError {
+        super(base, obcClass, nmsClass);
+        lastX = ReflectionUtil.getField(nmsClass, "lastX", double.class);
+        lastY = ReflectionUtil.getField(nmsClass, "lastY", double.class);
+        lastZ = ReflectionUtil.getField(nmsClass, "lastZ", double.class);
+        lastYaw = ReflectionUtil.getField(nmsClass, "lastYaw", float.class);
+        lastPitch = ReflectionUtil.getField(nmsClass, "lastPitch", float.class);
+        Validate.validateNotNull(lastX, lastY, lastZ, lastYaw, lastPitch);
+    }
+
+    @Override
+    public void setPositionAndLook(final Entity entity, final ISetPositionWithLook location) {
+        try {
+            performSet(entity, location);
+        }
+        catch (Throwable t) {
+            NCPAPIProvider.getNoCheatPlusAPI().getLogManager().warning(Streams.STATUS, "Could not retrieve last location for Entity: " + entity.getClass().getName());
+        }
+    }
+
+    private void performSet(final Entity entity, final ISetPositionWithLook location) throws IllegalArgumentException, IllegalAccessException {
+        final Object nmsObject = getHandle(entity);
+        location.setX(lastX.getDouble(nmsObject));
+        location.setY(lastY.getDouble(nmsObject));
+        location.setZ(lastZ.getDouble(nmsObject));
+        location.setYaw(lastYaw.getFloat(nmsObject));
+        location.setPitch(lastPitch.getFloat(nmsObject));
+    }
+
+    @Override
+    protected void fail() {
+        throw new RuntimeException("Not available."); // To be caught internally.
+    }
+
+}

NCPCompatBukkit/src/main/java/fr/neatmonster/nocheatplus/compat/cbreflect/reflect/ReflectGetHandleBase.java

@@ -0,0 +1,45 @@
+package fr.neatmonster.nocheatplus.compat.cbreflect.reflect;
+
+import java.lang.reflect.Method;
+
+import fr.neatmonster.nocheatplus.utilities.ReflectionUtil;
+
+/**
+ * Base for reflection on entities
+ * 
+ * @author asofold
+ *
+ * @param <BO>
+ *            Bukkit object type for getHandle.
+ */
+public abstract class ReflectGetHandleBase <BO> {
+
+    public final Method obcGetHandle;
+
+    public ReflectGetHandleBase(ReflectBase base, Class<?> obcClass, Class<?> nmsClass) throws ClassNotFoundException {
+        // getHandle
+        obcGetHandle = ReflectionUtil.getMethodNoArgs(obcClass, "getHandle");
+        // TODO: Consider throw in case of getHandle missing.
+    }
+
+    /**
+     * Invoke getHandle on the bukkit object.
+     * 
+     * @param bukkitObject
+     * @return
+     */
+    public Object getHandle(BO bukkitObject) {
+        // TODO: CraftPlayer check (isAssignableFrom)?
+        if (this.obcGetHandle == null) {
+            fail();
+        }
+        final Object handle = ReflectionUtil.invokeMethodNoArgs(this.obcGetHandle, bukkitObject);
+        if (handle == null) {
+            fail();
+        }
+        return handle;
+    }
+
+    protected abstract void fail();
+
+}

NCPCompatBukkit/src/main/java/fr/neatmonster/nocheatplus/compat/cbreflect/reflect/ReflectHelper.java

@@ -49,12 +49,12 @@ public class ReflectHelper {
     protected final ReflectBase reflectBase;
 
     protected final ReflectBlockPosition reflectBlockPosition;
-    protected final ReflectBlock reflectBlock;
+    protected final ReflectBlockSix reflectBlock;
     protected final ReflectMaterial reflectMaterial;
     protected final ReflectWorld reflectWorld;
 
     protected final ReflectDamageSource reflectDamageSource;
-    protected final ReflectEntity reflectEntity;
+    protected final ReflectEntityDamage reflectEntity;
     protected final ReflectPlayer reflectPlayer;
 
     protected final ReflectGenericAttributes reflectGenericAttributes;
@@ -72,12 +72,12 @@ public class ReflectHelper {
             }
             catch (ClassNotFoundException ex) {}
             this.reflectBlockPosition = reflectBlockPosition;
-            this.reflectBlock = new ReflectBlock(this.reflectBase, this.reflectBlockPosition);
+            this.reflectBlock = new ReflectBlockSix(this.reflectBase, this.reflectBlockPosition);
             this.reflectMaterial = new ReflectMaterial(this.reflectBase);
             this.reflectWorld = new ReflectWorld(this.reflectBase);
 
             this.reflectDamageSource = new ReflectDamageSource(this.reflectBase);
-            this.reflectEntity = new ReflectEntity(this.reflectBase, this.reflectDamageSource);
+            this.reflectEntity = new ReflectEntityDamage(this.reflectBase, this.reflectDamageSource);
             this.reflectPlayer = new ReflectPlayer(this.reflectBase, this.reflectDamageSource);
             ReflectGenericAttributes reflectGenericAttributes = null;
             ReflectAttributeInstance reflectAttributeInstance = null;

NCPCompatBukkit/src/main/java/fr/neatmonster/nocheatplus/compat/cbreflect/reflect/ReflectLivingEntity.java

@@ -4,7 +4,7 @@ import java.lang.reflect.Method;
 
 import fr.neatmonster.nocheatplus.utilities.ReflectionUtil;
 
-public class ReflectLivingEntity extends ReflectEntity {
+public class ReflectLivingEntity extends ReflectEntityDamage {
 
     public final Method nmsGetHealth;
 

NCPCore/src/main/java/fr/neatmonster/nocheatplus/components/location/IEntityAccessLastPositionAndLook.java

@@ -17,6 +17,6 @@ public interface IEntityAccessLastPositionAndLook {
      *            This instance gets updated by last coordinates and looking
      *            direction.
      */
-    public void setPositionAndLook(Entity entity, ISetLocationWithLook location);
+    public void setPositionAndLook(Entity entity, ISetPositionWithLook location);
 
 }

NCPPlugin/src/main/java/fr/neatmonster/nocheatplus/compat/EntityAccessFactory.java

@@ -1,6 +1,7 @@
 package fr.neatmonster.nocheatplus.compat;
 
 import fr.neatmonster.nocheatplus.NCPAPIProvider;
+import fr.neatmonster.nocheatplus.compat.cbreflect.reflect.ReflectEntityLastPositionAndLook;
 import fr.neatmonster.nocheatplus.components.location.IEntityAccessLastPositionAndLook;
 import fr.neatmonster.nocheatplus.logging.Streams;
 
@@ -28,11 +29,33 @@ public class EntityAccessFactory {
     }
 
     private void setupLastPositionWithLook() {
-        final String[] names = new String[] {
-
-        };
         IEntityAccessLastPositionAndLook res = null;
-        // TODO:
+//        // Reference by class name (native access).
+//        final String[] names = new String[] {
+//                // TODO: Spigot 1.9: fr.neatmonster.nocheatplus.compat.spigotcb1_9_R1.EntityAccessLastPositionAndLook
+//        };
+//        for (final String name : names) {
+//            try {
+//                res = (IEntityAccessLastPositionAndLook) Class.forName(name).newInstance();
+//                if (res != null) {
+//                    break;
+//                }
+//            }
+//            catch (Throwable t) {
+//                // Skip.
+//            }
+//        }
+        // Reflection based.
+        if (res == null) {
+            try {
+                res = new ReflectEntityLastPositionAndLook();
+            }
+            catch (Throwable t) {
+                // Ignore.
+                NCPAPIProvider.getNoCheatPlusAPI().getLogManager().debug(Streams.TRACE_FILE, t);
+            }
+        }
+        // Register / log.
         register(IEntityAccessLastPositionAndLook.class, res);
     }