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Diffstat (limited to 'ovr_sdk_win_23.0.0/LibOVRKernel/Src/Kernel/OVR_System.h')
| -rw-r--r-- | ovr_sdk_win_23.0.0/LibOVRKernel/Src/Kernel/OVR_System.h | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/ovr_sdk_win_23.0.0/LibOVRKernel/Src/Kernel/OVR_System.h b/ovr_sdk_win_23.0.0/LibOVRKernel/Src/Kernel/OVR_System.h new file mode 100644 index 0000000..4ed3484 --- /dev/null +++ b/ovr_sdk_win_23.0.0/LibOVRKernel/Src/Kernel/OVR_System.h @@ -0,0 +1,181 @@ +/************************************************************************************ + +PublicHeader: OVR +Filename : OVR_System.h +Content : General kernel initialization/cleanup, including that + of the memory allocator. +Created : September 19, 2012 +Notes : + +Copyright : Copyright (c) Facebook Technologies, LLC and its affiliates. All rights reserved. + +Licensed under the Oculus Master SDK License Version 1.0 (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 + +https://developer.oculus.com/licenses/oculusmastersdk-1.0 + +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_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 std::atomic<T*> SingletonInstance; + static T* SlowGetInstance(); + + struct ZeroInitializer { + ZeroInitializer() { + SingletonInstance = nullptr; + } + }; + ZeroInitializer zeroInitializer; + + protected: + ~SystemSingletonBase() { + // Make sure the instance gets set to zero on dtor + if (SingletonInstance.load() == this) + SingletonInstance = nullptr; + } + + public: + static OVR_FORCE_INLINE T* GetInstance() { + // Fast version + // Note: The singleton instance is stored in an std::atomic<> 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> +std::atomic<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() override; + +// 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.load()) \ + 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(); + + // Halt all system threads (call before Destroy). + static void OVR_CDECL Stop(); + + // De-initializes System more, finalizing the threading system and destroying + // the global memory allocator. + static void OVR_CDECL Destroy(); + + // Dump any leaked allocations + static void OVR_CDECL CheckForAllocatorLeaks(); +}; + +} // namespace OVR + +#endif |