Issue 1848 - Clean up local reference handling

jni/JniLogSystem.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 18 matching lines @@
 static void JNICALL JniDtor(JNIEnv* env, jclass clazz, jlong ptr)
 {
   delete JniLongToTypePtr<JniLogSystemCallback>(ptr);
 }
 
 JniLogSystemCallback::JniLogSystemCallback(JNIEnv* env, jobject callbackObject)
   : JniCallbackBase(env, callbackObject), AdblockPlus::LogSystem(), logLevelClass(new JniGlobalReference<jclass>(env, env->FindClass(PKG("LogSystem$LogLevel"))))
 {
 }
 
-void JniLogSystemCallback::operator()(AdblockPlus::LogSystem::LogLevel logLevel, const std::string& message, const std::string& source)
+void JniLogSystemCallback::operator()(AdblockPlus::LogSystem::LogLevel logLevel,
+    const std::string& message, const std::string& source)
 {
   JNIEnvAcquire env(GetJavaVM());
 
-  jclass clazz = env->GetObjectClass(GetCallbackObject());
-  jmethodID method = env->GetMethodID(clazz, "logCallback", "(" TYP("LogSystem$LogLevel") "Ljava/lang/String;Ljava/lang/String;)V");
+  jmethodID method = env->GetMethodID(
+      *JniLocalReference<jclass>(*env,
+          env->GetObjectClass(GetCallbackObject())),
+      "logCallback",
+      "(" TYP("LogSystem$LogLevel") "Ljava/lang/String;Ljava/lang/String;)V");
 
   // TODO: Set log level from Java and handle it here (to reduce C++->Java calls)
 
   if (method)
   {
     const char* enumName = 0;
 
     switch (logLevel)
     {
     default:
@@ skipping 10 matching lines @@
       enumName = "WARN";
       break;
     case AdblockPlus::LogSystem::LOG_LEVEL_ERROR:
       enumName = "ERROR";
       break;
     }
 
     jclass enumClass = logLevelClass->Get();
     if (enumClass)
     {
-      jfieldID enumField = env->GetStaticFieldID(enumClass, enumName, TYP("LogSystem$LogLevel"));
-      jobject jLogLevel = env->GetStaticObjectField(enumClass, enumField);
+      jfieldID enumField = env->GetStaticFieldID(enumClass, enumName,
+          TYP("LogSystem$LogLevel"));
+      JniLocalReference<jobject> jLogLevel(*env,
+          env->GetStaticObjectField(enumClass, enumField));
 
-      jstring jMessage = env->NewStringUTF(message.c_str());
-      jstring jSource = env->NewStringUTF(source.c_str());
+      JniLocalReference<jstring> jMessage(*env,
+          env->NewStringUTF(message.c_str()));
+      JniLocalReference<jstring> jSource(*env,
+          env->NewStringUTF(source.c_str()));
 
-      env->CallVoidMethod(GetCallbackObject(), method, jLogLevel, jMessage, jSource);
+      env->CallVoidMethod(GetCallbackObject(), method, *jLogLevel, *jMessage,
+          *jSource);
     }
 
     CheckAndLogJavaException(*env);
   }
 }
 
 static JNINativeMethod methods[] =
 {
   { (char*)"ctor", (char*)"(Ljava/lang/Object;)J", (void*)JniCtor },
   { (char*)"dtor", (char*)"(J)V", (void*)JniDtor }
 };
 
 extern "C" JNIEXPORT void JNICALL Java_org_adblockplus_libadblockplus_LogSystem_registerNatives(JNIEnv *env, jclass clazz)
 {
   env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0]));
 }