| /* |
| * Copyright (C) 2007 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef ANDROID_UTILS_SINGLETON_H |
| #define ANDROID_UTILS_SINGLETON_H |
| |
| #include <stdint.h> |
| #include <sys/types.h> |
| #include <utils/Mutex.h> |
| #include <utils/threads.h> |
| #include <cutils/compiler.h> |
| |
| namespace android { |
| // --------------------------------------------------------------------------- |
| |
| template <typename TYPE> |
| class ANDROID_API Singleton |
| { |
| public: |
| static TYPE& getInstance() { |
| Mutex::Autolock _l(sLock); |
| TYPE* instance = sInstance; |
| if (instance == 0) { |
| instance = new TYPE(); |
| sInstance = instance; |
| } |
| return *instance; |
| } |
| |
| static bool hasInstance() { |
| Mutex::Autolock _l(sLock); |
| return sInstance != 0; |
| } |
| |
| protected: |
| ~Singleton() { } |
| Singleton() { } |
| |
| private: |
| Singleton(const Singleton&); |
| Singleton& operator = (const Singleton&); |
| static Mutex sLock; |
| static TYPE* sInstance; |
| }; |
| |
| template <typename TYPE> |
| Mutex Singleton<TYPE>::sLock; |
| |
| template <typename TYPE> |
| TYPE* Singleton<TYPE>::sInstance; |
| |
| /* |
| * use ANDROID_SINGLETON_STATIC_INSTANCE(TYPE) in your implementation file |
| * (eg: <TYPE>.cpp) to create the static instance of Singleton<>'s attributes, |
| * and avoid to have a copy of them in each compilation units Singleton<TYPE> |
| * is used. |
| * NOTE: we use a version of Mutex ctor that takes a parameter, because |
| * for some unknown reason using the default ctor doesn't emit the variable! |
| */ |
| |
| #define ANDROID_SINGLETON_STATIC_INSTANCE(TYPE) \ |
| template<> ::android::Mutex \ |
| (::android::Singleton< TYPE >::sLock)(::android::Mutex::PRIVATE); \ |
| template<> TYPE* ::android::Singleton< TYPE >::sInstance(0); \ |
| template class ::android::Singleton< TYPE >; |
| |
| |
| // --------------------------------------------------------------------------- |
| }; // namespace android |
| |
| #endif // ANDROID_UTILS_SINGLETON_H |
| |