Implement reflective method invocation.

Change-Id: Ib3af9d7e00bf226398610b5ac6efbfe3eb2d15e8
diff --git a/src/java_lang_reflect_Method.cc b/src/java_lang_reflect_Method.cc
index 188614f..6ddb436 100644
--- a/src/java_lang_reflect_Method.cc
+++ b/src/java_lang_reflect_Method.cc
@@ -17,6 +17,7 @@
 #include "jni_internal.h"
 #include "class_linker.h"
 #include "object.h"
+#include "reflection.h"
 
 #include "JniConstants.h" // Last to avoid problems with LOG redefinition.
 
@@ -24,7 +25,6 @@
 
 namespace {
 
-
 // We move the DECLARED_SYNCHRONIZED flag into the SYNCHRONIZED
 // position, because the callers of this function are trying to convey
 // the "traditional" meaning of the flags to their callers.
@@ -40,9 +40,73 @@
   return FixupMethodFlags(Decode<Object*>(env, jmethod)->AsMethod()->GetAccessFlags());
 }
 
+jobject Method_invokeNative(JNIEnv* env, jobject javaMethod, jobject javaReceiver, jobject javaArgs, jclass javaDeclaringClass, jobject javaParams, jclass, jint, jboolean) {
+  Thread* self = Thread::Current();
+  ScopedThreadStateChange tsc(self, Thread::kRunnable);
+
+  jmethodID mid = env->FromReflectedMethod(javaMethod);
+  Method* m = reinterpret_cast<Method*>(mid);
+  Object* receiver = NULL;
+  if (!m->IsStatic()) {
+    // Check that the receiver is non-null and an instance of the field's declaring class.
+    receiver = Decode<Object*>(env, javaReceiver);
+    Class* declaringClass = Decode<Class*>(env, javaDeclaringClass);
+    if (!VerifyObjectInClass(env, receiver, declaringClass)) {
+      return NULL;
+    }
+
+    // Find the actual implementation of the virtual method.
+    m = receiver->GetClass()->FindVirtualMethodForVirtualOrInterface(m);
+  }
+
+  // Get our arrays of arguments and their types, and check they're the same size.
+  ObjectArray<Object>* objects = Decode<ObjectArray<Object>*>(env, javaArgs);
+  ObjectArray<Class>* classes = Decode<ObjectArray<Class>*>(env, javaParams);
+  int32_t arg_count = (objects != NULL) ? objects->GetLength() : 0;
+  if (arg_count != classes->GetLength()) {
+    self->ThrowNewException("Ljava/lang/IllegalArgumentException;",
+        "wrong number of arguments; expected %d, got %d",
+        classes->GetLength(), arg_count);
+    return NULL;
+  }
+
+  // Translate javaArgs to a jvalue[].
+  UniquePtr<jvalue[]> args(new jvalue[arg_count]);
+  JValue* decoded_args = reinterpret_cast<JValue*>(args.get());
+  for (int32_t i = 0; i < arg_count; ++i) {
+    Object* arg = objects->Get(i);
+    Class* dst_class = classes->Get(i);
+    if (dst_class->IsPrimitive()) {
+      if (!UnboxPrimitive(env, arg, dst_class, decoded_args[i])) {
+        return NULL;
+      }
+    } else {
+      args[i].l = AddLocalReference<jobject>(env, arg);
+    }
+  }
+
+  // Invoke the method.
+  JValue value = InvokeWithJValues(env, javaReceiver, mid, args.get());
+
+  // Wrap any exception with "Ljava/lang/reflect/InvocationTargetException;" and return early.
+  if (self->IsExceptionPending()) {
+    jthrowable th = env->ExceptionOccurred();
+    env->ExceptionClear();
+    jclass exception_class = env->FindClass("java/lang/reflect/InvocationTargetException");
+    jmethodID mid = env->GetMethodID(exception_class, "<init>", "(Ljava/lang/Throwable;)V");
+    jobject exception_instance = env->NewObject(exception_class, mid, th);
+    env->Throw(reinterpret_cast<jthrowable>(exception_instance));
+    return NULL;
+  }
+
+  // Box if necessary and return.
+  BoxPrimitive(env, m->GetReturnType(), value);
+  return AddLocalReference<jobject>(env, value.l);
+}
+
 static JNINativeMethod gMethods[] = {
   NATIVE_METHOD(Method, getMethodModifiers, "(Ljava/lang/Class;Ljava/lang/reflect/AccessibleObject;I)I"),
-  //NATIVE_METHOD(Method, invokeNative, "(Ljava/lang/Object;[Ljava/lang/Object;Ljava/lang/Class;[Ljava/lang/Class;Ljava/lang/Class;IZ)Ljava/lang/Object;"),
+  NATIVE_METHOD(Method, invokeNative, "(Ljava/lang/Object;[Ljava/lang/Object;Ljava/lang/Class;[Ljava/lang/Class;Ljava/lang/Class;IZ)Ljava/lang/Object;"),
 };
 
 }  // namespace