Allow changing of lambda SAM types (alter method descriptor)

This is currently the 'slow' implementation and actually
slows down invokeinterface too - need to get the fast version
done...

springloaded/src/main/java/org/springsource/loaded/GlobalConfiguration.java

@@ -362,4 +362,16 @@ public class GlobalConfiguration {
 		}
 		debugplugins = debugPlugins;
 	}
+	
+	public final static boolean isJava18orHigher;
+	
+	static {
+		String version = System.getProperty("java.version");
+		if (version.startsWith("1.8")) {
+			isJava18orHigher = true;
+		}
+		else {
+			isJava18orHigher = false;
+		}
+	}
 }

springloaded/src/main/java/org/springsource/loaded/MethodInvokerRewriter.java

@@ -1236,8 +1236,15 @@ public class MethodInvokerRewriter {
 
 				mv.visitLdcInsn(name + desc); // [targetInstance paramArray targetInstance nameAndDescriptor]
 
-				// calling __execute(params array, this, name+desc)
-				mv.visitMethodInsn(INVOKEINTERFACE, owner, mDynamicDispatchName, mDynamicDispatchDescriptor);
+				if (GlobalConfiguration.isJava18orHigher) {
+					// if the target is a generated lambda callsite object then calling __execute isn't going to work as those
+					// types don't have the method in them!
+					mv.visitMethodInsn(INVOKESTATIC, tRegistryType, "iiIntercept", "(Ljava/lang/Object;[Ljava/lang/Object;Ljava/lang/Object;Ljava/lang/String;)Ljava/lang/Object;");
+				}
+				else {
+					// calling __execute(params array, this, name+desc)
+					mv.visitMethodInsn(INVOKEINTERFACE, owner, mDynamicDispatchName, mDynamicDispatchDescriptor);
+				}
 
 				insertAppropriateReturn(returnType);
 				Label gotolabel = new Label();

springloaded/src/main/java/org/springsource/loaded/TypeRegistry.java

@@ -1259,6 +1259,33 @@ public class TypeRegistry {
 		return null; // let it fail anyway
 	}
 
+	/**
+	 * See notes.md#001
+	 * 
+	 */
+	public static Object iiIntercept(Object instance, Object[] params, Object instance2, String nameAndDescriptor) {
+		Class<?> clazz= instance.getClass();
+		try {
+			if (clazz.getName().contains("$$Lambda")) {
+				// There will only be one method, the SAM method
+				Method[] ms = instance.getClass().getDeclaredMethods();
+				Method m = ms[0];
+				m.setAccessible(true);
+				Object o = m.invoke(instance, params);
+				return o;	
+			}
+			else {
+				// Do what you were going to do...
+				Method m = instance.getClass().getDeclaredMethod("__execute",Object[].class,Object.class,String.class);
+				m.setAccessible(true);
+				return m.invoke(instance, params, instance, nameAndDescriptor);
+			}
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+		return null;
+	}
+
 	@UsedByGeneratedCode
 	public static __DynamicallyDispatchable ispcheck(int ids, String nameAndDescriptor) {
 		if (GlobalConfiguration.isRuntimeLogging && log.isLoggable(Level.FINER)) {

springloaded/src/main/java/org/springsource/loaded/agent/SpringLoadedPreProcessor.java

@@ -41,6 +41,7 @@ import org.springsource.loaded.TypeRegistry;
 import org.springsource.loaded.Utils;
 import org.springsource.loaded.SystemClassReflectionRewriter.RewriteResult;
 import org.springsource.loaded.ri.ReflectiveInterceptor;
+import org.springsource.loaded.support.Java8;
 
 /**
  * The entry point for the agent - all classes that can be modified will be passed into preProcess(). They have to be dealt with in
@@ -148,6 +149,10 @@ public class SpringLoadedPreProcessor implements Constants {
 					//		return rr.bytes;
 					//	}
 				}
+				else if (slashedClassName.equals("java/lang/invoke/InnerClassLambdaMetafactory")) {
+					bytes = Java8.enhanceInnerClassLambdaMetaFactory(bytes);
+					return bytes;
+				}
 			}
 			return bytes;
 		}

springloaded/src/main/java/org/springsource/loaded/support/Java8.java

@@ -140,4 +140,15 @@ public class Java8 {
 		
 		return LambdaMetafactory.metafactory(caller, invokedName, invokedType, samMethodType, implMethod, instantiatedMethodType);
 	}
+
+	/**
+	 * The metafactory we are enhancing is responsible for generating the anonymous classes that will call the lambda methods in our type
+	 * 
+	 * @param bytes
+	 * @return
+	 */
+	public static byte[] enhanceInnerClassLambdaMetaFactory(byte[] bytes) {
+		// TODO Auto-generated method stub
+		return null;
+	}
 }