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

libadblockplus-android/jni/JniWebRequest.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
@@ skipping 61 matching lines @@
       *JniLocalReference<jclass>(*env,
           env->GetObjectClass(GetCallbackObject())),
       "httpGET",
       "(Ljava/lang/String;Ljava/util/List;)" TYP("ServerResponse"));
 
   AdblockPlus::ServerResponse sResponse;
   sResponse.status = AdblockPlus::WebRequest::NS_ERROR_FAILURE;
 
   if (method)
   {
     JniLocalReference<jobject> arrayList(*env, NewJniArrayList(*env));

[anton, 2016/09/23 13:05:25]

Consider using LinkedList instead of ArrayList - for adding one-by-one use case
it's more efficient. Also since we know what list class we create, we can find
the method once during searching list class and skip using
"JniGetAddToListMethod" at all 

[diegocarloslima, 2016/11/04 11:34:19]

Yeah, LinkedList are better for insertion while ArraysList are better for
retrieving elements. If we do more insertions that retrieval operations for this
list, I do agree that it makes more sense, but the performance gain is not
really relevant if the list don't get really big.

     jmethodID addMethod = JniGetAddToListMethod(*env, *arrayList);

[anton, 2016/09/23 13:05:25]

Now searching for the method once

 
     for (AdblockPlus::HeaderList::const_iterator it = requestHeaders.begin(),
         end = requestHeaders.end(); it != end; it++)
     {
-      JniLocalReference<jobject> headerEntry(*env, NewHeaderEntry(*env, it->first, it->second));
+      JniLocalReference<jobject> headerEntry(*env, NewTuple(*env, it->first, it->second));
       JniAddObjectToList(*env, *arrayList, addMethod, *headerEntry);
     }
 
     JniLocalReference<jobject> response(*env,
         env->CallObjectMethod(GetCallbackObject(), method,
             *JniLocalReference<jstring>(*env, env->NewStringUTF(url.c_str())),
             *arrayList));
 
     if (!env->ExceptionCheck())
     {
@@ skipping 30 matching lines @@
         }
       }
     }
   }
 
   CheckAndLogJavaException(*env);
 
   return sResponse;
 }
 
-jobject JniWebRequest::NewHeaderEntry(JNIEnv* env, const std::string& a,
+jobject JniWebRequest::NewTuple(JNIEnv* env, const std::string& a,
     const std::string& b) const
 {
   jmethodID factory = env->GetMethodID(headerEntryClass->Get(), "<init>",
       "(Ljava/lang/String;Ljava/lang/String;)V");
 
   JniLocalReference<jstring> strA(env, env->NewStringUTF(a.c_str()));
   JniLocalReference<jstring> strB(env, env->NewStringUTF(b.c_str()));
 
   return env->NewObject(headerEntryClass->Get(), factory, *strA, *strB);
 }
 
 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_WebRequest_registerNatives(JNIEnv *env, jclass clazz)
 {
   env->RegisterNatives(clazz, methods, sizeof(methods) / sizeof(methods[0]));
 }