New JNI bindings

jni/Utils.cpp

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 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 21 matching lines @@
   const char *s = pEnv->GetStringUTFChars(str, &iscopy);
   jsize len = pEnv->GetStringUTFLength(str);
 
   const std::string value(s, len);
 
   pEnv->ReleaseStringUTFChars(str, s);
 
   return value;
 }
 
-std::string JniJava2StdString(JNIEnv* env, jstring str)
+std::string JniJavaToStdString(JNIEnv* env, jstring str)
 {
   if (!str)
   {
     return std::string();
   }
 
   const char* cStr = env->GetStringUTFChars(str, 0);
   std::string ret(cStr);
   env->ReleaseStringUTFChars(str, cStr);
 
@@ skipping 19 matching lines @@
   env->ThrowNew(clazz, message.c_str());
 }
 
 void JniThrowException(JNIEnv* env, const std::exception& e)
 {
   JniThrowException(env, e.what());
 }
 
 void JniThrowException(JNIEnv* env)
 {
-  JniThrowException(env, "Unknown exception from libAdblockPlus");
+  JniThrowException(env, "Unknown exception from libadblockplus");
 }
+
+JNIEnvAcquire::JNIEnvAcquire(JavaVM* javaVM)
+  : javaVM(javaVM), jniEnv(0), attachmentStatus(0)
+{
+  attachmentStatus = javaVM->GetEnv((void **)&jniEnv, ABP_JNI_VERSION);
+  if (attachmentStatus == JNI_EDETACHED)
+  {
+    if (javaVM->AttachCurrentThread(&jniEnv, 0))
+    {
+      // This one is FATAL, we can't recover from this (because without a JVM we're dead), so
+      // throwing a runtime_exception in a ctor can be tolerated here IMHO
+      throw std::runtime_error("Failed to get JNI environment");
+    }
+  }
+}
+
+JNIEnvAcquire::~JNIEnvAcquire()
+{
+  if (attachmentStatus == JNI_EDETACHED)
+  {
+    javaVM->DetachCurrentThread();
+  }
+}