1 /*
   2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2018, Google and/or its affiliates. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  */
  24 
  25 #include <string>
  26 
  27 #include "ExceptionCheckingJniEnv.hpp"
  28 
  29 namespace {
  30 
  31 template<class T = void*>
  32 class JNIVerifier {
  33  public:
  34   JNIVerifier(ExceptionCheckingJniEnv *env, const std::string& base_msg)
  35       : _env(env), _base_msg(base_msg) {
  36   }
  37 
  38   ~JNIVerifier() {
  39     JNIEnv* jni_env = _env->GetJNIEnv();
  40     if (jni_env->ExceptionCheck()) {
  41       _env->HandleError(_base_msg.c_str());
  42     } else {
  43       if (!_return_error.empty()) {
  44         const std::string msg = _base_msg + ":" + _return_error;
  45         _env->HandleError(msg.c_str());
  46       }
  47     }
  48   }
  49 
  50   T ResultNotNull(T ptr) {
  51     if (ptr == NULL) {
  52       _return_error = "Return is NULL";
  53     }
  54     return ptr;
  55   }
  56 
  57  private:
  58   ExceptionCheckingJniEnv* _env;
  59   std::string _base_msg;
  60   std::string _return_error;
  61 };
  62 
  63 }
  64 
  65 jclass ExceptionCheckingJniEnv::GetObjectClass(jobject obj) {
  66   JNIVerifier<jclass> marker(this, "GetObjectClass");
  67   return marker.ResultNotNull(_jni_env->GetObjectClass(obj));
  68 }
  69 
  70 jfieldID ExceptionCheckingJniEnv::GetFieldID(jclass klass, const char *name, const char* type) {
  71   JNIVerifier<jfieldID> marker(this, "GetObjectClass");
  72   return marker.ResultNotNull(_jni_env->GetFieldID(klass, name, type));
  73 }
  74 
  75 jobject ExceptionCheckingJniEnv::GetObjectField(jobject obj, jfieldID field) {
  76   JNIVerifier<jobject> marker(this, "GetObjectField");
  77   return marker.ResultNotNull(_jni_env->GetObjectField(obj, field));
  78 }
  79 
  80 void ExceptionCheckingJniEnv::SetObjectField(jobject obj, jfieldID field, jobject value) {
  81   JNIVerifier<> marker(this, "SetObjectField");
  82   _jni_env->SetObjectField(obj, field, value);
  83 }
  84 
  85 jobject ExceptionCheckingJniEnv::NewGlobalRef(jobject obj) {
  86   JNIVerifier<jobject> marker(this, "GetObjectField");
  87   return marker.ResultNotNull(_jni_env->NewGlobalRef(obj));
  88 }
  89 
  90 void ExceptionCheckingJniEnv::DeleteGlobalRef(jobject obj) {
  91   JNIVerifier<> marker(this, "DeleteGlobalRef");
  92   _jni_env->DeleteGlobalRef(obj);
  93 }