Issue 4442 - Cache class and ctors references in JNI_Load/UnLoad

libadblockplus-android/jni/JniNotification.cpp

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <AdblockPlus.h>
 #include "Utils.h"
-#include "JniJsValue.h"
+#include "JniNotification.h"
+
+// precached in JNI_OnLoad and released in JNI_OnUnload
+JniGlobalReference<jclass>* notificationEnumClass;
+
+void JniNotification_OnLoad(JavaVM* vm, JNIEnv* env, void* reserved)
+{
+  notificationEnumClass = new JniGlobalReference<jclass>(env, env->FindClass(PKG("Notification$Type")));
+}
+
+void JniNotification_OnUnload(JavaVM* vm, JNIEnv* env, void* reserved)
+{
+  if (notificationEnumClass)
+  {
+    delete notificationEnumClass;
+    notificationEnumClass = NULL;
+  }
+}
 
 static AdblockPlus::Notification* GetNotificationPtr(jlong ptr)
 {
   return JniLongToTypePtr<AdblockPlus::NotificationPtr>(ptr)->get();
 }
 
 static jobject JNICALL JniGetType(JNIEnv* env, jclass clazz, jlong ptr)
 {
   AdblockPlus::NotificationType type;
   try
@@ skipping 13 matching lines @@
     enumName = "INFORMATION";
     break;
   case AdblockPlus::NotificationType::NOTIFICATION_TYPE_QUESTION:
     enumName = "QUESTION";
     break;
   default:
     enumName = "INVALID";
     break;
   }
 
-  JniLocalReference<jclass> enumClass(
-      env,
-      env->FindClass(PKG("Notification$Type")));
-
   jfieldID enumField = env->GetStaticFieldID(
-      *enumClass,
+      notificationEnumClass->Get(),
       enumName,
       TYP("Notification$Type"));
 
-  return env->GetStaticObjectField(*enumClass, enumField);
+  return env->GetStaticObjectField(notificationEnumClass->Get(), enumField);
 }
 
 static jstring JniGetTitle(JNIEnv* env, jclass clazz, jlong ptr)
 {
   try
   {
     return env->NewStringUTF(GetNotificationPtr(ptr)->GetTexts().title.c_str());
   }
   CATCH_THROW_AND_RETURN(env, 0)
 }
@@ skipping 23 matching lines @@
   { (char*) "getTitle", (char*) "(J)Ljava/lang/String;", (void*) JniGetTitle },
   { (char*) "getType", (char*) "(J)" TYP("Notification$Type"), (void*) JniGetType }
 };
 
 extern "C" JNIEXPORT void JNICALL Java_org_adblockplus_libadblockplus_Notification_registerNatives(
     JNIEnv *env, jclass clazz)
 {
   env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0]));
 }