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Diffstat (limited to 'LibOVR/Src/Kernel/OVR_Threads.h')
| -rw-r--r-- | LibOVR/Src/Kernel/OVR_Threads.h | 407 |
1 files changed, 407 insertions, 0 deletions
diff --git a/LibOVR/Src/Kernel/OVR_Threads.h b/LibOVR/Src/Kernel/OVR_Threads.h new file mode 100644 index 0000000..307f107 --- /dev/null +++ b/LibOVR/Src/Kernel/OVR_Threads.h @@ -0,0 +1,407 @@ +/************************************************************************************ + +PublicHeader: None +Filename : OVR_Threads.h +Content : Contains thread-related (safe) functionality +Created : September 19, 2012 +Notes : + +Copyright : Copyright 2014 Oculus VR, Inc. All Rights reserved. + +Licensed under the Oculus VR Rift SDK License Version 3.1 (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-3.1 + +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_Threads_h +#define OVR_Threads_h + +#include "OVR_Types.h" +#include "OVR_Atomic.h" +#include "OVR_RefCount.h" +#include "OVR_Array.h" + +// Defines the infinite wait delay timeout +#define OVR_WAIT_INFINITE 0xFFFFFFFF + +// To be defined in the project configuration options +#ifdef OVR_ENABLE_THREADS + + +namespace OVR { + +//----------------------------------------------------------------------------------- +// ****** Declared classes + +// Declared with thread support only +class Mutex; +class WaitCondition; +class Event; +// Implementation forward declarations +class MutexImpl; +class WaitConditionImpl; + + + +//----------------------------------------------------------------------------------- +// ***** Mutex + +// Mutex class represents a system Mutex synchronization object that provides access +// serialization between different threads, allowing one thread mutually exclusive access +// to a resource. Mutex is more heavy-weight then Lock, but supports WaitCondition. + +class Mutex +{ + friend class WaitConditionImpl; + friend class MutexImpl; + + MutexImpl *pImpl; + +public: + // Constructor/destructor + Mutex(bool recursive = 1); + ~Mutex(); + + // Locking functions + void DoLock(); + bool TryLock(); + void Unlock(); + + // Returns 1 if the mutes is currently locked by another thread + // Returns 0 if the mutex is not locked by another thread, and can therefore be acquired. + bool IsLockedByAnotherThread(); + + // Locker class; Used for automatic locking of a mutex withing scope + class Locker + { + public: + Mutex *pMutex; + Locker(Mutex *pmutex) + { pMutex = pmutex; pMutex->DoLock(); } + ~Locker() + { pMutex->Unlock(); } + }; +}; + + +//----------------------------------------------------------------------------------- +// ***** WaitCondition + +/* + WaitCondition is a synchronization primitive that can be used to implement what is known as a monitor. + Dependent threads wait on a wait condition by calling Wait(), and get woken up by other threads that + call Notify() or NotifyAll(). + + The unique feature of this class is that it provides an atomic way of first releasing a Mutex, and then + starting a wait on a wait condition. If both the mutex and the wait condition are associated with the same + resource, this ensures that any condition checked for while the mutex was locked does not change before + the wait on the condition is actually initiated. +*/ + +class WaitCondition +{ + friend class WaitConditionImpl; + // Internal implementation structure + WaitConditionImpl *pImpl; + +public: + // Constructor/destructor + WaitCondition(); + ~WaitCondition(); + + // Release mutex and wait for condition. The mutex is re-aquired after the wait. + // Delay is specified in milliseconds (1/1000 of a second). + bool Wait(Mutex *pmutex, unsigned delay = OVR_WAIT_INFINITE); + + // Notify a condition, releasing at one object waiting + void Notify(); + // Notify a condition, releasing all objects waiting + void NotifyAll(); +}; + + +//----------------------------------------------------------------------------------- +// ***** Event + +// Event is a wait-able synchronization object similar to Windows event. +// Event can be waited on until it's signaled by another thread calling +// either SetEvent or PulseEvent. + +class Event +{ + // Event state, its mutex and the wait condition + volatile bool State; + volatile bool Temporary; + mutable Mutex StateMutex; + WaitCondition StateWaitCondition; + + void updateState(bool newState, bool newTemp, bool mustNotify); + +public: + Event(bool setInitially = 0) : State(setInitially), Temporary(false) { } + ~Event() { } + + // Wait on an event condition until it is set + // Delay is specified in milliseconds (1/1000 of a second). + bool Wait(unsigned delay = OVR_WAIT_INFINITE); + + // Set an event, releasing objects waiting on it + void SetEvent() + { updateState(true, false, true); } + + // Reset an event, un-signaling it + void ResetEvent() + { updateState(false, false, false); } + + // Set and then reset an event once a waiter is released. + // If threads are already waiting, they will be notified and released + // If threads are not waiting, the event is set until the first thread comes in + void PulseEvent() + { updateState(true, true, true); } +}; + + +//----------------------------------------------------------------------------------- +// ***** Thread class + +// ThreadId uniquely identifies a thread; returned by GetCurrentThreadId() and +// Thread::GetThreadId. +typedef void* ThreadId; + + +// *** Thread flags + +// Indicates that the thread is has been started, i.e. Start method has been called, and threads +// OnExit() method has not yet been called/returned. +#define OVR_THREAD_STARTED 0x01 +// This flag is set once the thread has ran, and finished. +#define OVR_THREAD_FINISHED 0x02 +// This flag is set temporarily if this thread was started suspended. It is used internally. +#define OVR_THREAD_START_SUSPENDED 0x08 +// This flag is used to ask a thread to exit. Message driven threads will usually check this flag +// and finish once it is set. +#define OVR_THREAD_EXIT 0x10 + + +class Thread : public RefCountBase<Thread> +{ // NOTE: Waitable must be the first base since it implements RefCountImpl. + +public: + + // *** Callback functions, can be used instead of overriding Run + + // Run function prototypes. + // Thread function and user handle passed to it, executed by the default + // Thread::Run implementation if not null. + typedef int (*ThreadFn)(Thread *pthread, void* h); + + // Thread ThreadFunction1 is executed if not 0, otherwise ThreadFunction2 is tried + ThreadFn ThreadFunction; + // User handle passes to a thread + void* UserHandle; + + // Thread state to start a thread with + enum ThreadState + { + NotRunning = 0, + Running = 1, + Suspended = 2 + }; + + // Thread priority + enum ThreadPriority + { + CriticalPriority, + HighestPriority, + AboveNormalPriority, + NormalPriority, + BelowNormalPriority, + LowestPriority, + IdlePriority, + }; + + // Thread constructor parameters + struct CreateParams + { + CreateParams(ThreadFn func = 0, void* hand = 0, UPInt ssize = 128 * 1024, + int proc = -1, ThreadState state = NotRunning, ThreadPriority prior = NormalPriority) + : threadFunction(func), userHandle(hand), stackSize(ssize), + processor(proc), initialState(state), priority(prior) {} + ThreadFn threadFunction; // Thread function + void* userHandle; // User handle passes to a thread + UPInt stackSize; // Thread stack size + int processor; // Thread hardware processor + ThreadState initialState; // + ThreadPriority priority; // Thread priority + }; + + // *** Constructors + + // A default constructor always creates a thread in NotRunning state, because + // the derived class has not yet been initialized. The derived class can call Start explicitly. + // "processor" parameter specifies which hardware processor this thread will be run on. + // -1 means OS decides this. Implemented only on Win32 + Thread(UPInt stackSize = 128 * 1024, int processor = -1); + // Constructors that initialize the thread with a pointer to function. + // An option to start a thread is available, but it should not be used if classes are derived from Thread. + // "processor" parameter specifies which hardware processor this thread will be run on. + // -1 means OS decides this. Implemented only on Win32 + Thread(ThreadFn threadFunction, void* userHandle = 0, UPInt stackSize = 128 * 1024, + int processor = -1, ThreadState initialState = NotRunning); + // Constructors that initialize the thread with a create parameters structure. + explicit Thread(const CreateParams& params); + + // Destructor. + virtual ~Thread(); + + // Waits for all Threads to finish; should be called only from the root + // application thread. Once this function returns, we know that all other + // thread's references to Thread object have been released. + static void OVR_CDECL FinishAllThreads(); + + + // *** Overridable Run function for thread processing + + // - returning from this method will end the execution of the thread + // - return value is usually 0 for success + virtual int Run(); + // Called after return/exit function + virtual void OnExit(); + + + // *** Thread management + + // Starts the thread if its not already running + // - internally sets up the threading and calls Run() + // - initial state can either be Running or Suspended, NotRunning will just fail and do nothing + // - returns the exit code + virtual bool Start(ThreadState initialState = Running); + + // Quits with an exit code + virtual void Exit(int exitCode=0); + + // Suspend the thread until resumed + // Returns 1 for success, 0 for failure. + bool Suspend(); + // Resumes currently suspended thread + // Returns 1 for success, 0 for failure. + bool Resume(); + + // Static function to return a pointer to the current thread + //static Thread* GetThread(); + + + // *** Thread status query functions + + bool GetExitFlag() const; + void SetExitFlag(bool exitFlag); + + // Determines whether the thread was running and is now finished + bool IsFinished() const; + // Determines if the thread is currently suspended + bool IsSuspended() const; + // Returns current thread state + ThreadState GetThreadState() const; + + // Returns the number of available CPUs on the system + static int GetCPUCount(); + + // Returns the thread exit code. Exit code is initialized to 0, + // and set to the return value if Run function after the thread is finished. + inline int GetExitCode() const { return ExitCode; } + // Returns an OS handle +#if defined(OVR_OS_WIN32) + void* GetOSHandle() const { return ThreadHandle; } +#else + pthread_t GetOSHandle() const { return ThreadHandle; } +#endif + +#if defined(OVR_OS_WIN32) + ThreadId GetThreadId() const { return IdValue; } +#else + ThreadId GetThreadId() const { return (ThreadId)GetOSHandle(); } +#endif + + static int GetOSPriority(ThreadPriority); + // *** Sleep + + // Sleep secs seconds + static bool Sleep(unsigned secs); + // Sleep msecs milliseconds + static bool MSleep(unsigned msecs); + + + // *** Debugging functionality +#if defined(OVR_OS_WIN32) + virtual void SetThreadName( const char* name ); +#else + virtual void SetThreadName( const char* name ) { OVR_UNUSED(name); } +#endif + +private: +#if defined(OVR_OS_WIN32) + friend unsigned WINAPI Thread_Win32StartFn(void *pthread); + +#else + friend void *Thread_PthreadStartFn(void * phandle); + + static int InitAttr; + static pthread_attr_t Attr; +#endif + +protected: + // Thread state flags + AtomicInt<UInt32> ThreadFlags; + AtomicInt<SInt32> SuspendCount; + UPInt StackSize; + + // Hardware processor which this thread is running on. + int Processor; + ThreadPriority Priority; + +#if defined(OVR_OS_WIN32) + void* ThreadHandle; + volatile ThreadId IdValue; + + // System-specific cleanup function called from destructor + void CleanupSystemThread(); + +#else + pthread_t ThreadHandle; +#endif + + // Exit code of the thread, as returned by Run. + int ExitCode; + + // Internal run function. + int PRun(); + // Finishes the thread and releases internal reference to it. + void FinishAndRelease(); + + void Init(const CreateParams& params); + + // Protected copy constructor + Thread(const Thread &source) : RefCountBase<Thread>() { OVR_UNUSED(source); } + +}; + +// Returns the unique Id of a thread it is called on, intended for +// comparison purposes. +ThreadId GetCurrentThreadId(); + + +} // OVR + +#endif // OVR_ENABLE_THREADS +#endif // OVR_Threads_h |