diff options
-rw-r--r-- | indra/llcommon/llsingleton.h | 95 |
1 files changed, 45 insertions, 50 deletions
diff --git a/indra/llcommon/llsingleton.h b/indra/llcommon/llsingleton.h index 829c7e4192..7558bf4fae 100644 --- a/indra/llcommon/llsingleton.h +++ b/indra/llcommon/llsingleton.h @@ -61,6 +61,7 @@ class LLSingleton : private boost::noncopyable private: typedef enum e_init_state { + UNINITIALIZED, CONSTRUCTING, INITIALIZING, INITIALIZED, @@ -68,30 +69,23 @@ private: } EInitState; // stores pointer to singleton instance - // and tracks initialization state of singleton - struct SingletonInstanceData + struct SingletonLifetimeManager { - EInitState mInitState; - DERIVED_TYPE* mSingletonInstance; - - SingletonInstanceData() - : mSingletonInstance(NULL), - mInitState(CONSTRUCTING) + SingletonLifetimeManager() { construct(); } - void construct() + static void construct() { - sReentrantConstructorGuard = true; - mSingletonInstance = new DERIVED_TYPE(); - mInitState = INITIALIZING; - sReentrantConstructorGuard = false; + sData.mInitState = CONSTRUCTING; + sData.mInstance = new DERIVED_TYPE(); + sData.mInitState = INITIALIZING; } - ~SingletonInstanceData() + ~SingletonLifetimeManager() { - if (mInitState != DELETED) + if (sData.mInitState != DELETED) { deleteSingleton(); } @@ -101,9 +95,8 @@ private: public: virtual ~LLSingleton() { - SingletonInstanceData& data = getSingletonData(); - data.mSingletonInstance = NULL; - data.mInitState = DELETED; + sData.mInstance = NULL; + sData.mInitState = DELETED; } /** @@ -128,41 +121,45 @@ public: */ static void deleteSingleton() { - delete getSingletonData().mSingletonInstance; - getSingletonData().mSingletonInstance = NULL; - getSingletonData().mInitState = DELETED; + delete sData.mInstance; + sData.mInstance = NULL; + sData.mInitState = DELETED; } static DERIVED_TYPE* getInstance() { - SingletonInstanceData& data = getSingletonData(); + static SingletonLifetimeManager sLifeTimeMgr; - if (data.mInitState == CONSTRUCTING) + switch (sData.mInitState) { + case UNINITIALIZED: + // should never be uninitialized at this point + llassert(false); + break; + case CONSTRUCTING: llerrs << "Tried to access singleton " << typeid(DERIVED_TYPE).name() << " from singleton constructor!" << llendl; - } - - if (data.mInitState == DELETED) - { - llwarns << "Trying to access deleted singleton " << typeid(DERIVED_TYPE).name() << " creating new instance" << llendl; - data.construct(); - } - - if (data.mInitState == INITIALIZING) - { + break; + case INITIALIZING: // go ahead and flag ourselves as initialized so we can be reentrant during initialization - data.mInitState = INITIALIZED; - data.mSingletonInstance->initSingleton(); + sData.mInitState = INITIALIZED; + sData.mInstance->initSingleton(); + return sData.mInstance; + break; + case INITIALIZED: + return sData.mInstance; + case DELETED: + llwarns << "Trying to access deleted singleton " << typeid(DERIVED_TYPE).name() << " creating new instance" << llendl; + SingletonLifetimeManager::construct(); + return sData.mInstance; } - - return data.mSingletonInstance; + + return NULL; } static DERIVED_TYPE* getIfExists() { - SingletonInstanceData& data = getSingletonData(); - return data.mSingletonInstance; + return sData.mInstance; } // Reference version of getInstance() @@ -176,31 +173,29 @@ public: // Use this to avoid accessing singletons before the can safely be constructed static bool instanceExists() { - return !sReentrantConstructorGuard && getSingletonData().mInitState == INITIALIZED; + return sData.mInitState == INITIALIZED; } // Has this singleton already been deleted? // Use this to avoid accessing singletons from a static object's destructor static bool destroyed() { - return getSingletonData().mInitState == DELETED; + return sData.mInitState == DELETED; } private: - static SingletonInstanceData& getSingletonData() - { - // this is static to cache the lookup results - static SingletonInstanceData sData; - return sData; - } - virtual void initSingleton() {} - static bool sReentrantConstructorGuard; + struct SingletonData + { + EInitState mInitState; + DERIVED_TYPE* mInstance; + }; + static SingletonData sData; }; template<typename T> -bool LLSingleton<T>::sReentrantConstructorGuard = false; +typename LLSingleton<T>::SingletonData LLSingleton<T>::sData; #endif |