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 "ExceptionCheckingJniEnv.hpp"
  26 
  27 namespace {
  28 
  29 template<class T = void*>
  30 class JNIVerifier {
  31  public:
  32   JNIVerifier(ExceptionCheckingJniEnv *env, const char* base_msg)
  33       : _env(env), _base_msg(base_msg), _return_error(NULL) {
  34   }
  35 
  36   ~JNIVerifier() {
  37     JNIEnv* jni_env = _env->GetJNIEnv();
  38     if (jni_env->ExceptionCheck()) {
  39       _env->HandleError(_base_msg);
  40       return;
  41     }
  42 
  43     if (_return_error != NULL) {
  44       ProcessReturnError();
  45     }
  46   }
  47 
  48   void ProcessReturnError() {
  49     int len = snprintf(NULL, 0, "%s : %s", _base_msg, _return_error) + 1;
  50 
  51     if (len <= 0) {
  52       _env->HandleError(_return_error);
  53       return;
  54     }
  55 
  56     char* full_message = (char*) malloc(len);
  57     if (full_message == NULL) {
  58       _env->HandleError(_return_error);
  59       return;
  60     }
  61 
  62     snprintf(full_message, len, "%s : %s", _base_msg, _return_error);
  63 
  64     _env->HandleError(full_message);
  65     free(full_message);
  66   }
  67 
  68   T ResultNotNull(T ptr) {
  69     if (ptr == NULL) {
  70       _return_error = "Return is NULL";
  71     }
  72     return ptr;
  73   }
  74 
  75  private:
  76   ExceptionCheckingJniEnv* _env;
  77   const char* _base_msg;
  78   const char* _return_error;
  79 };
  80 
  81 }
  82 
  83 jclass ExceptionCheckingJniEnv::GetObjectClass(jobject obj) {
  84   JNIVerifier<jclass> marker(this, "GetObjectClass");
  85   return marker.ResultNotNull(_jni_env->GetObjectClass(obj));
  86 }
  87 
  88 jfieldID ExceptionCheckingJniEnv::GetFieldID(jclass klass, const char *name, const char* type) {
  89   JNIVerifier<jfieldID> marker(this, "GetObjectClass");
  90   return marker.ResultNotNull(_jni_env->GetFieldID(klass, name, type));
  91 }
  92 
  93 jobject ExceptionCheckingJniEnv::GetObjectField(jobject obj, jfieldID field) {
  94   JNIVerifier<jobject> marker(this, "GetObjectField");
  95   return marker.ResultNotNull(_jni_env->GetObjectField(obj, field));
  96 }
  97 
  98 void ExceptionCheckingJniEnv::SetObjectField(jobject obj, jfieldID field, jobject value) {
  99   JNIVerifier<> marker(this, "SetObjectField");
 100   _jni_env->SetObjectField(obj, field, value);
 101 }
 102 
 103 jobject ExceptionCheckingJniEnv::NewGlobalRef(jobject obj) {
 104   JNIVerifier<jobject> marker(this, "GetObjectField");
 105   return marker.ResultNotNull(_jni_env->NewGlobalRef(obj));
 106 }
 107 
 108 void ExceptionCheckingJniEnv::DeleteGlobalRef(jobject obj) {
 109   JNIVerifier<> marker(this, "DeleteGlobalRef");
 110   _jni_env->DeleteGlobalRef(obj);
 111 }