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 SCOPED_LOCAL_REF_H_included 18 #define SCOPED_LOCAL_REF_H_included 19 20 #include "jni.h" 21 22 #include <stddef.h> 23 #include "JNIHelp.h" // for DISALLOW_COPY_AND_ASSIGN. 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 } 31 ~ScopedLocalRef()32 ~ScopedLocalRef() { 33 reset(); 34 } 35 36 void reset(T ptr = NULL) { 37 if (ptr != mLocalRef) { 38 if (mLocalRef != NULL) { 39 mEnv->DeleteLocalRef(mLocalRef); 40 } 41 mLocalRef = ptr; 42 } 43 } 44 release()45 T release() __attribute__((warn_unused_result)) { 46 T localRef = mLocalRef; 47 mLocalRef = NULL; 48 return localRef; 49 } 50 get()51 T get() const { 52 return mLocalRef; 53 } 54 55 private: 56 JNIEnv* const mEnv; 57 T mLocalRef; 58 59 DISALLOW_COPY_AND_ASSIGN(ScopedLocalRef); 60 }; 61 62 #endif // SCOPED_LOCAL_REF_H_included 63