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Diffstat (limited to 'LibOVRKernel/Src/Kernel/OVR_System.h')
| -rw-r--r-- | LibOVRKernel/Src/Kernel/OVR_System.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/LibOVRKernel/Src/Kernel/OVR_System.h b/LibOVRKernel/Src/Kernel/OVR_System.h new file mode 100644 index 0000000..d66fbe7 --- /dev/null +++ b/LibOVRKernel/Src/Kernel/OVR_System.h @@ -0,0 +1,174 @@ +/************************************************************************************ + +PublicHeader: OVR +Filename : OVR_System.h +Content : General kernel initialization/cleanup, including that + of the memory allocator. +Created : September 19, 2012 +Notes : + +Copyright : Copyright 2014 Oculus VR, LLC All Rights reserved. + +Licensed under the Oculus VR Rift SDK License Version 3.2 (the "License"); +you may not use the Oculus VR Rift SDK except in compliance with the License, +which is provided at the time of installation or download, or which +otherwise accompanies this software in either electronic or hard copy form. + +You may obtain a copy of the License at + +http://www.oculusvr.com/licenses/LICENSE-3.2 + +Unless required by applicable law or agreed to in writing, the Oculus VR SDK +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 OVR_System_h +#define OVR_System_h + +#include "OVR_Allocator.h" +#include "OVR_Log.h" +#include "OVR_Atomic.h" + +namespace OVR { + + +//----------------------------------------------------------------------------- +// SystemSingleton + +// Subsystems are implemented using the Singleton pattern. +// To avoid code duplication in all the places where Singletons are defined, +// The pattern is defined once here and used everywhere. + +class SystemSingletonInternal +{ + friend class System; + + // Allows for including this class in the shutdown list. + SystemSingletonInternal* NextShutdownSingleton; + + // No copying allowed + OVR_NON_COPYABLE(SystemSingletonInternal); + +public: + // Call this to register for a call to OnThreadDestroy and OnSystemDestroy before the + // Kernel is shut down. OnThreadDestroy is called before any remaining existing threads + // are exited. Registered callbacks are called in the reverse order they were registered. + // You would typically call this at the end of your SystemSingletonInternal subclass' constructor. + // The registered objects are not deleted on shutdown; they would have to do that themselves within + // OnSystemDestroy or via a compiler-generated static destruction. + void RegisterDestroyCallback(); + void PushDestroyCallbacks() { RegisterDestroyCallback(); } // For backward compatibility. + +protected: + SystemSingletonInternal() : + NextShutdownSingleton(nullptr) + { + } + + virtual ~SystemSingletonInternal(){} + + // Initializes the SystemSingletonInternal. + // You can register for an automatic call to this function by calling PushInitCallbacks. + // The registration of an automatic call to this is not required, but may be useful if + // you need to postpone your initialization until after Kernel is initialized. + // You cannot call PushInitCallbacks or PushDestroyCallbacks while within this function. + virtual void OnSystemInit() {} + + // Called just before waiting for threads to exit. + // Listeners are called in the opposite order they were registered. + // This function is useful for terminating threads at the right time before the rest of the system is shut down. + // Note: The singleton must not delete itself here, as OnSystemDestroy will subsequently be called for it. + virtual void OnThreadDestroy() {} + + // Shuts down the SystemSingletonInternal. + // You can register for an automatic call to this function by calling PushDestroyCallbacks. + // The registration of an automatic call to this is not required, but may be useful if + // you need to delay your shutdown until application exit time. + // You cannot call PushInitCallbacks or PushDestroyCallbacks while within this function. + // This function may delete this. + virtual void OnSystemDestroy() {} +}; + +// Singletons derive from this class +template<class T> +class SystemSingletonBase : public SystemSingletonInternal +{ + static AtomicPtr<T> SingletonInstance; + static T* SlowGetInstance(); + +protected: + ~SystemSingletonBase() + { + // Make sure the instance gets set to zero on dtor + if (SingletonInstance == this) + SingletonInstance = nullptr; + } + +public: + static OVR_FORCE_INLINE T* GetInstance() + { + // Fast version + // Note: The singleton instance is stored in an AtomicPtr<> to allow it to be accessed + // atomically from multiple threads without locks. + T* instance = SingletonInstance; + return instance ? instance : SlowGetInstance(); + } +}; + +// For reference, see N3337 14.5.1.3 (Static data members of class templates): +template<class T> OVR::AtomicPtr<T> OVR::SystemSingletonBase<T>::SingletonInstance; + +// Place this in the singleton class in the header file +#define OVR_DECLARE_SINGLETON(T) \ + friend class OVR::SystemSingletonBase<T>; \ +private: \ + T(); \ + virtual ~T(); \ + virtual void OnSystemDestroy(); + +// Place this in the singleton class source file +#define OVR_DEFINE_SINGLETON(T) \ + namespace OVR { \ + template<> T* SystemSingletonBase<T>::SlowGetInstance() \ + { \ + static OVR::Lock lock; \ + OVR::Lock::Locker locker(&lock); \ + if (!SingletonInstance) \ + SingletonInstance = new T; \ + return SingletonInstance; \ + } \ + } + + +// ***** System Core Initialization class + +// System initialization must take place before any other OVR_Kernel objects are used; +// this is done my calling System::Init(). Among other things, this is necessary to +// initialize the memory allocator. Similarly, System::Destroy must be +// called before program exist for proper cleanup. Both of these tasks can be achieved by +// simply creating System object first, allowing its constructor/destructor do the work. + +class System +{ +public: + // Returns 'true' if system was properly initialized. + static bool OVR_CDECL IsInitialized(); + + // Initializes System core. Users can override memory implementation by passing + // a different Allocator here. + static void OVR_CDECL Init(Log* log = Log::ConfigureDefaultLog(LogMask_Debug), + Allocator *palloc = DefaultAllocator::InitSystemSingleton()); + + // De-initializes System more, finalizing the threading system and destroying + // the global memory allocator. + static void OVR_CDECL Destroy(); +}; + + +} // namespace OVR + +#endif |