1 /* 2 * Copyright (C) 2010 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 #ifndef SCOPEDLOCALREF_H_ 18 #define SCOPEDLOCALREF_H_ 19 20 #include <conscrypt/macros.h> 21 #include <jni.h> 22 23 #include <stddef.h> 24 25 // A smart pointer that deletes a JNI local reference when it goes out of scope. 26 template <typename T> 27 class ScopedLocalRef { 28 public: ScopedLocalRef(JNIEnv * env,T localRef)29 ScopedLocalRef(JNIEnv* env, T localRef) : mEnv(env), mLocalRef(localRef) {} 30 ~ScopedLocalRef()31 ~ScopedLocalRef() { 32 reset(); 33 } 34 35 void reset(T ptr = nullptr) { 36 if (ptr != mLocalRef) { 37 if (mLocalRef != nullptr) { 38 mEnv->DeleteLocalRef(mLocalRef); 39 } 40 mLocalRef = ptr; 41 } 42 } 43 44 CONSCRYPT_WARN_UNUSED release()45 T release() { 46 T localRef = mLocalRef; 47 mLocalRef = nullptr; 48 return localRef; 49 } 50 get()51 T get() const { 52 return mLocalRef; 53 } 54 55 private: 56 JNIEnv* mEnv; 57 T mLocalRef; 58 59 // Disallow copy and assignment. 60 ScopedLocalRef(const ScopedLocalRef&); 61 void operator=(const ScopedLocalRef&); 62 }; 63 64 #endif // SCOPEDLOCALREF_H_ 65