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      1 /*
      2  * Copyright 2016, The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *     http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <jni.h>
     18 
     19 namespace android {
     20 
     21 /* JNI Helpers for wifi_hal to WifiNative bridge implementation */
     22 
     23 class JNIHelper;
     24 
     25 template<typename T>
     26 class JNIObject {
     27 protected:
     28     JNIHelper &mHelper;
     29     T mObj;
     30 public:
     31     JNIObject(JNIHelper &helper, T obj);
     32     JNIObject(const JNIObject<T>& rhs);
     33     virtual ~JNIObject();
     34     JNIHelper& getHelper() const {
     35         return mHelper;
     36     }
     37     T get() const {
     38         return mObj;
     39     }
     40     operator T() const {
     41         return mObj;
     42     }
     43     bool isNull() const {
     44         return mObj == NULL;
     45     }
     46     void release();
     47     T detach() {
     48         T tObj = mObj;
     49         mObj = NULL;
     50         return tObj;
     51     }
     52     T clone();
     53     JNIObject<T>& operator = (const JNIObject<T>& rhs) {
     54         release();
     55         mHelper = rhs.mHelper;
     56         mObj = rhs.mObj;
     57         return *this;
     58     }
     59     void print() {
     60         ALOGD("holding %p", mObj);
     61     }
     62 
     63 private:
     64     template<typename T2>
     65     JNIObject(const JNIObject<T2>& rhs);  // NOLINT(implicit)
     66 };
     67 
     68 class JNIHelper {
     69     JavaVM *mVM;
     70     JNIEnv *mEnv;
     71 
     72 public :
     73     explicit JNIHelper(JavaVM *vm);
     74     explicit JNIHelper(JNIEnv *env);
     75     ~JNIHelper();
     76 
     77     /* helpers to deal with static members */
     78     JNIObject<jbyteArray> newByteArray(int num);
     79     void setByteArrayRegion(jbyteArray array, int from, int to, const jbyte *bytes);
     80 
     81 private:
     82     /* Jni wrappers */
     83     friend class JNIObject<jbyteArray>;
     84     jobject newLocalRef(jobject obj);
     85     void deleteLocalRef(jobject obj);
     86 };
     87 
     88 template<typename T>
     89 JNIObject<T>::JNIObject(JNIHelper &helper, T obj)
     90       : mHelper(helper), mObj(obj)
     91 { }
     92 
     93 template<typename T>
     94 JNIObject<T>::JNIObject(const JNIObject<T>& rhs)
     95       : mHelper(rhs.mHelper), mObj(NULL)
     96 {
     97       mObj = (T)mHelper.newLocalRef(rhs.mObj);
     98 }
     99 
    100 template<typename T>
    101 JNIObject<T>::~JNIObject() {
    102       release();
    103 }
    104 
    105 template<typename T>
    106 void JNIObject<T>::release()
    107 {
    108       if (mObj != NULL) {
    109           mHelper.deleteLocalRef(mObj);
    110           mObj = NULL;
    111       }
    112 }
    113 
    114 template<typename T>
    115 T JNIObject<T>::clone()
    116 {
    117       return mHelper.newLocalRef(mObj);
    118 }
    119 }
    120 
    121 #define THROW(env, message)      (env).throwException(message, __LINE__)
    122