/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2018, Google and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "ExceptionCheckingJniEnv.hpp"

namespace {

template<class T = void*>

class JNIVerifier {

 public:

  JNIVerifier(ExceptionCheckingJniEnv *env, const char* base_msg)

      : _env(env), _base_msg(base_msg), _return_error(NULL) {

  }

  ~JNIVerifier() {

    JNIEnv* jni_env = _env->GetJNIEnv();

    if (jni_env->ExceptionCheck()) {

      _env->HandleError(_base_msg);

      return;

    }

    if (_return_error != NULL) {

      ProcessReturnError();

    }

  }

  void ProcessReturnError() {

    int len = snprintf(NULL, 0, "%s : %s", _base_msg, _return_error) + 1;

    if (len <= 0) {

      _env->HandleError(_return_error);

      return;

    }

    char* full_message = (char*) malloc(len);

    if (full_message == NULL) {

      _env->HandleError(_return_error);

      return;

    }

    snprintf(full_message, len, "%s : %s", _base_msg, _return_error);

    _env->HandleError(full_message);

    free(full_message);

  }

  T ResultNotNull(T ptr) {

    if (ptr == NULL) {

      _return_error = "Return is NULL";

    }

    return ptr;

  }

 private:

  ExceptionCheckingJniEnv* _env;

  const char* const _base_msg;

  const char* _return_error;

};

}

jclass ExceptionCheckingJniEnv::GetObjectClass(jobject obj) {

  JNIVerifier<jclass> marker(this, "GetObjectClass");

  return marker.ResultNotNull(_jni_env->GetObjectClass(obj));

}

jfieldID ExceptionCheckingJniEnv::GetFieldID(jclass klass, const char *name, const char* type) {

  JNIVerifier<jfieldID> marker(this, "GetObjectClass");

  return marker.ResultNotNull(_jni_env->GetFieldID(klass, name, type));

}

jobject ExceptionCheckingJniEnv::GetObjectField(jobject obj, jfieldID field) {

  JNIVerifier<jobject> marker(this, "GetObjectField");

  return marker.ResultNotNull(_jni_env->GetObjectField(obj, field));

}

void ExceptionCheckingJniEnv::SetObjectField(jobject obj, jfieldID field, jobject value) {

  JNIVerifier<> marker(this, "SetObjectField");

  _jni_env->SetObjectField(obj, field, value);

}

jobject ExceptionCheckingJniEnv::NewGlobalRef(jobject obj) {

  JNIVerifier<jobject> marker(this, "GetObjectField");

  return marker.ResultNotNull(_jni_env->NewGlobalRef(obj));

}

void ExceptionCheckingJniEnv::DeleteGlobalRef(jobject obj) {

  JNIVerifier<> marker(this, "DeleteGlobalRef");

  _jni_env->DeleteGlobalRef(obj);

}