Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2007 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 ANDROID_UTILS_SINGLETON_H |
| 18 | #define ANDROID_UTILS_SINGLETON_H |
| 19 | |
| 20 | #include <stdint.h> |
Mathias Agopian | 22dbf39 | 2017-02-28 15:06:51 -0800 | [diff] [blame] | 21 | |
| 22 | // some vendor code assumes they have atoi() after including this file. |
| 23 | #include <stdlib.h> |
| 24 | |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 25 | #include <sys/types.h> |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 26 | #include <utils/Mutex.h> |
Romain Guy | 5cd3247 | 2011-10-12 13:48:51 -0700 | [diff] [blame] | 27 | #include <cutils/compiler.h> |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 28 | |
| 29 | namespace android { |
| 30 | // --------------------------------------------------------------------------- |
| 31 | |
Colin Cross | b014509 | 2017-02-23 14:48:51 -0800 | [diff] [blame] | 32 | // Singleton<TYPE> may be used in multiple libraries, only one of which should |
| 33 | // define the static member variables using ANDROID_SINGLETON_STATIC_INSTANCE. |
| 34 | // Turn off -Wundefined-var-template so other users don't get: |
| 35 | // instantiation of variable 'android::Singleton<TYPE>::sLock' required here, |
| 36 | // but no definition is available |
| 37 | #if defined(__clang__) |
| 38 | #pragma clang diagnostic push |
| 39 | #pragma clang diagnostic ignored "-Wundefined-var-template" |
| 40 | #endif |
| 41 | |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 42 | template <typename TYPE> |
Romain Guy | 5cd3247 | 2011-10-12 13:48:51 -0700 | [diff] [blame] | 43 | class ANDROID_API Singleton |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 44 | { |
| 45 | public: |
| 46 | static TYPE& getInstance() { |
| 47 | Mutex::Autolock _l(sLock); |
| 48 | TYPE* instance = sInstance; |
| 49 | if (instance == 0) { |
| 50 | instance = new TYPE(); |
| 51 | sInstance = instance; |
| 52 | } |
| 53 | return *instance; |
| 54 | } |
Romain Guy | 4e30623 | 2010-09-08 18:04:33 -0700 | [diff] [blame] | 55 | |
| 56 | static bool hasInstance() { |
| 57 | Mutex::Autolock _l(sLock); |
| 58 | return sInstance != 0; |
| 59 | } |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 60 | |
| 61 | protected: |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 62 | ~Singleton() { } |
| 63 | Singleton() { } |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 64 | |
| 65 | private: |
| 66 | Singleton(const Singleton&); |
| 67 | Singleton& operator = (const Singleton&); |
| 68 | static Mutex sLock; |
| 69 | static TYPE* sInstance; |
| 70 | }; |
| 71 | |
Colin Cross | b014509 | 2017-02-23 14:48:51 -0800 | [diff] [blame] | 72 | #if defined(__clang__) |
| 73 | #pragma clang diagnostic pop |
| 74 | #endif |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 75 | |
Mathias Agopian | d8c95cc | 2009-04-17 14:15:18 -0700 | [diff] [blame] | 76 | /* |
| 77 | * use ANDROID_SINGLETON_STATIC_INSTANCE(TYPE) in your implementation file |
| 78 | * (eg: <TYPE>.cpp) to create the static instance of Singleton<>'s attributes, |
| 79 | * and avoid to have a copy of them in each compilation units Singleton<TYPE> |
| 80 | * is used. |
Mathias Agopian | 24ed905 | 2010-05-28 15:13:30 -0700 | [diff] [blame] | 81 | * NOTE: we use a version of Mutex ctor that takes a parameter, because |
| 82 | * for some unknown reason using the default ctor doesn't emit the variable! |
Mathias Agopian | d8c95cc | 2009-04-17 14:15:18 -0700 | [diff] [blame] | 83 | */ |
| 84 | |
Mathias Agopian | 24ed905 | 2010-05-28 15:13:30 -0700 | [diff] [blame] | 85 | #define ANDROID_SINGLETON_STATIC_INSTANCE(TYPE) \ |
Chih-Hung Hsieh | c777f21 | 2014-12-10 13:55:21 -0800 | [diff] [blame] | 86 | template<> ::android::Mutex \ |
| 87 | (::android::Singleton< TYPE >::sLock)(::android::Mutex::PRIVATE); \ |
| 88 | template<> TYPE* ::android::Singleton< TYPE >::sInstance(0); \ |
| 89 | template class ::android::Singleton< TYPE >; |
Mathias Agopian | d8c95cc | 2009-04-17 14:15:18 -0700 | [diff] [blame] | 90 | |
| 91 | |
Mathias Agopian | 6b35f97 | 2009-04-10 14:24:30 -0700 | [diff] [blame] | 92 | // --------------------------------------------------------------------------- |
| 93 | }; // namespace android |
| 94 | |
| 95 | #endif // ANDROID_UTILS_SINGLETON_H |
| 96 | |