X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/6d167489bdf17d55d9bd11be834bc17277661063..3342663931cc6d203c1d2ded6da44a17347cb0e7:/include/wx/thread.h?ds=sidebyside diff --git a/include/wx/thread.h b/include/wx/thread.h index 641ce6330b..319829ba71 100644 --- a/include/wx/thread.h +++ b/include/wx/thread.h @@ -40,20 +40,27 @@ enum wxMutexError { - wxMUTEX_NO_ERROR = 0, - wxMUTEX_DEAD_LOCK, // Mutex has been already locked by THE CALLING thread - wxMUTEX_BUSY, // Mutex has been already locked by ONE thread - wxMUTEX_UNLOCKED, - wxMUTEX_MISC_ERROR + wxMUTEX_NO_ERROR = 0, + wxMUTEX_DEAD_LOCK, // Mutex has been already locked by THE CALLING thread + wxMUTEX_BUSY, // Mutex has been already locked by ONE thread + wxMUTEX_UNLOCKED, + wxMUTEX_MISC_ERROR }; enum wxThreadError { - wxTHREAD_NO_ERROR = 0, // No error - wxTHREAD_NO_RESOURCE, // No resource left to create a new thread - wxTHREAD_RUNNING, // The thread is already running - wxTHREAD_NOT_RUNNING, // The thread isn't running - wxTHREAD_MISC_ERROR // Some other error + wxTHREAD_NO_ERROR = 0, // No error + wxTHREAD_NO_RESOURCE, // No resource left to create a new thread + wxTHREAD_RUNNING, // The thread is already running + wxTHREAD_NOT_RUNNING, // The thread isn't running + wxTHREAD_KILLED, // Thread we waited for had to be killed + wxTHREAD_MISC_ERROR // Some other error +}; + +enum wxThreadKind +{ + wxTHREAD_DETACHED, + wxTHREAD_JOINABLE }; // defines the interval of priority @@ -73,6 +80,7 @@ enum // you should consider wxMutexLocker whenever possible instead of directly // working with wxMutex class - it is safer +class WXDLLEXPORT wxConditionInternal; class WXDLLEXPORT wxMutexInternal; class WXDLLEXPORT wxMutex { @@ -92,14 +100,14 @@ public: bool IsLocked() const { return (m_locked > 0); } protected: - friend class wxCondition; - // no assignment operator nor copy ctor wxMutex(const wxMutex&); wxMutex& operator=(const wxMutex&); int m_locked; - wxMutexInternal *p_internal; + wxMutexInternal *m_internal; + + friend class wxConditionInternal; }; // a helper class which locks the mutex in the ctor and unlocks it in the dtor: @@ -109,8 +117,9 @@ class WXDLLEXPORT wxMutexLocker { public: // lock the mutex in the ctor - wxMutexLocker(wxMutex& mutex) : m_mutex(mutex) - { m_isOk = m_mutex.Lock() == wxMUTEX_NO_ERROR; } + wxMutexLocker(wxMutex& mutex) + : m_isOk(FALSE), m_mutex(mutex) + { m_isOk = ( m_mutex.Lock() == wxMUTEX_NO_ERROR ); } // returns TRUE if mutex was successfully locked in ctor bool IsOk() const @@ -143,11 +152,11 @@ class WXDLLEXPORT wxCriticalSectionInternal; // in order to avoid any overhead under platforms where critical sections are // just mutexes make all wxCriticalSection class functions inline -#if !defined(__WXMSW__) && !defined(__WXPM__) && !defined(__WXMAC__) +#if !defined(__WXMSW__) && !defined(__WXPM__) #define WXCRITICAL_INLINE inline #define wxCRITSECT_IS_MUTEX 1 -#else // MSW || Mac || OS2 +#else // MSW || OS2 #define WXCRITICAL_INLINE #define wxCRITSECT_IS_MUTEX 0 @@ -206,40 +215,119 @@ private: }; // ---------------------------------------------------------------------------- -// Condition handler. +// wxCondition models a POSIX condition variable which allows one (or more) +// thread(s) to wait until some condition is fulfilled // ---------------------------------------------------------------------------- -class wxConditionInternal; class WXDLLEXPORT wxCondition { + DECLARE_NO_COPY_CLASS(wxCondition) + +public: + // constructor and destructor + + // Each wxCondition object is associated with with a wxMutex object The + // mutex object MUST be locked before calling Wait() + wxCondition(wxMutex& mutex); + + // dtor is not virtual, don't use this class polymorphically + ~wxCondition(); + + // NB: the associated mutex MUST be locked beforehand by the calling thread + // + // it atomically releases the lock on the associated mutex + // and starts waiting to be woken up by a Signal()/Broadcast() + // once its signaled, then it will wait until it can reacquire + // the lock on the associated mutex object, before returning. + void Wait(); + + // exactly as Wait() except that it may also return if the specified + // timeout ellapses even if the condition hasn't been signalled: in this + // case, the return value is FALSE, otherwise (i.e. in case of a normal + // return) it is TRUE + // + // the timeeout parameter specifies a interval that needs to be waited in + // milliseconds + bool Wait( unsigned long timeout_millis ); + + // NB: the associated mutex may or may not be locked by the calling thread + // + // this method unblocks one thread if any are blocking on the condition. + // if no thread is blocking in Wait(), then the signal is NOT remembered + // The thread which was blocking on Wait(), will then reacquire the lock + // on the associated mutex object before returning + void Signal(); + + // NB: the associated mutex may or may not be locked by the calling thread + // + // this method unblocks all threads if any are blocking on the condition. + // if no thread is blocking in Wait(), then the signal is NOT remembered + // The threads which were blocking on Wait(), will then reacquire the lock + // on the associated mutex object before returning. + void Broadcast(); + +private: + wxConditionInternal *m_internal; +}; + +// ---------------------------------------------------------------------------- +// wxSemaphore: a counter limiting the number of threads concurrently accessing +// a shared resource +// ---------------------------------------------------------------------------- + +class WXDLLEXPORT wxSemaphoreInternal; +class WXDLLEXPORT wxSemaphore +{ + DECLARE_NO_COPY_CLASS(wxSemaphore) + public: - // constructor & destructor - wxCondition(); - ~wxCondition(); - - // Waits indefinitely. - void Wait(wxMutex& mutex); - // Waits until a signal is raised or the timeout is elapsed. - bool Wait(wxMutex& mutex, unsigned long sec, unsigned long nsec); - // Raises a signal: only one "Waiter" is released. - void Signal(); - // Broadcasts to all "Waiters". - void Broadcast(); + // specifying a maxcount of 0 actually makes wxSemaphore behave as if there + // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex + wxSemaphore( int initialcount = 0, int maxcount = 0 ); + + // dtor is not virtual, don't use this class polymorphically + ~wxSemaphore(); + + // wait indefinitely, until the semaphore count goes beyond 0 + // and then decrement it and return (this method might have been called + // Acquire()) + void Wait(); + + // same as Wait(), but does not block, returns TRUE if successful and + // FALSE if the count is zero + bool TryWait(); + + // same as Wait(), but as a timeout limit, returns TRUE if the semaphore + // was acquired and FALSE if the timeout has ellapsed + bool Wait( unsigned long timeout_millis ); + + // increments the semaphore count and signals one of the waiting threads + void Post(); private: - wxConditionInternal *p_internal; + wxSemaphoreInternal *m_internal; }; // ---------------------------------------------------------------------------- -// Thread management class +// wxThread: class encpasulating a thread of execution // ---------------------------------------------------------------------------- -// FIXME Thread termination model is still unclear. Delete() should probably -// have a timeout after which the thread must be Kill()ed. +// there are two different kinds of threads: joinable and detached (default) +// ones. Only joinable threads can return a return code and only detached +// threads auto-delete themselves - the user should delete the joinable +// threads manually. // NB: in the function descriptions the words "this thread" mean the thread // created by the wxThread object while "main thread" is the thread created // during the process initialization (a.k.a. the GUI thread) + +// On VMS thread pointers are 64 bits (also needed for other systems??? +#ifdef __VMS + typedef unsigned long long wxThreadIdType; +#else + typedef unsigned long wxThreadIdType; +#endif + class wxThreadInternal; class WXDLLEXPORT wxThread { @@ -266,34 +354,75 @@ public: // NB: at least under MSW worker threads can not call ::wxSleep()! static void Sleep(unsigned long milliseconds); - // default constructor - wxThread(); + // get the number of system CPUs - useful with SetConcurrency() + // (the "best" value for it is usually number of CPUs + 1) + // + // Returns -1 if unknown, number of CPUs otherwise + static int GetCPUCount(); + + // Get the platform specific thread ID and return as a long. This + // can be used to uniquely identify threads, even if they are not + // wxThreads. This is used by wxPython. + static wxThreadIdType GetCurrentId(); + + // sets the concurrency level: this is, roughly, the number of threads + // the system tries to schedule to run in parallel. 0 means the + // default value (usually acceptable, but may not yield the best + // performance for this process) + // + // Returns TRUE on success, FALSE otherwise (if not implemented, for + // example) + static bool SetConcurrency(size_t level); + + // constructor only creates the C++ thread object and doesn't create (or + // start) the real thread + wxThread(wxThreadKind kind = wxTHREAD_DETACHED); + + // functions that change the thread state: all these can only be called + // from _another_ thread (typically the thread that created this one, e.g. + // the main thread), not from the thread itself - // function that change the thread state - // create a new thread - call Run() to start it - wxThreadError Create(); + // create a new thread and optionally set the stack size on + // platforms that support that - call Run() to start it + // (special cased for watcom which won't accept 0 default) - // starts execution of the thread - from the moment Run() is called the - // execution of wxThread::Entry() may start at any moment, caller + wxThreadError Create(unsigned int stackSize = 0); + + // starts execution of the thread - from the moment Run() is called + // the execution of wxThread::Entry() may start at any moment, caller // shouldn't suppose that it starts after (or before) Run() returns. wxThreadError Run(); - // stops the thread if it's running and deletes the wxThread object - // freeing its memory. This function should also be called if the - // Create() or Run() fails to free memory (otherwise it will be done by - // the thread itself when it terminates). The return value is the - // thread exit code if the thread was gracefully terminated, 0 if it - // wasn't running and -1 if an error occured. - ExitCode Delete(); + // stops the thread if it's running and deletes the wxThread object if + // this is a detached thread freeing its memory - otherwise (for + // joinable threads) you still need to delete wxThread object + // yourself. + // + // this function only works if the thread calls TestDestroy() + // periodically - the thread will only be deleted the next time it + // does it! + // + // will fill the rc pointer with the thread exit code if it's !NULL + wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL); + + // waits for a joinable thread to finish and returns its exit code + // + // Returns (ExitCode)-1 on error (for example, if the thread is not + // joinable) + ExitCode Wait(); // kills the thread without giving it any chance to clean up - should // not be used in normal circumstances, use Delete() instead. It is a // dangerous function that should only be used in the most extreme - // cases! The wxThread object is deleted by Kill() if thread was - // killed (i.e. no errors occured). + // cases! + // + // The wxThread object is deleted by Kill() if the thread is + // detachable, but you still have to delete it manually for joinable + // threads. wxThreadError Kill(); - // pause a running thread + // pause a running thread: as Delete(), this only works if the thread + // calls TestDestroy() regularly wxThreadError Pause(); // resume a paused thread @@ -308,10 +437,6 @@ public: // Get the current priority. unsigned int GetPriority() const; - // Get the thread ID - a platform dependent number which uniquely - // identifies a thread inside a process - unsigned long GetID() const; - // thread status inquiries // Returns true if the thread is alive: i.e. running or suspended bool IsAlive() const; @@ -320,11 +445,22 @@ public: // Returns true if the thread is suspended bool IsPaused() const; + // is the thread of detached kind? + bool IsDetached() const { return m_isDetached; } + + // Get the thread ID - a platform dependent number which uniquely + // identifies a thread inside a process + wxThreadIdType GetId() const; + // called when the thread exits - in the context of this thread // // NB: this function will not be called if the thread is Kill()ed virtual void OnExit() { } + // dtor is public, but the detached threads should never be deleted - use + // Delete() instead (or leave the thread terminate by itself) + virtual ~wxThread(); + protected: // Returns TRUE if the thread was asked to terminate: this function should // be called by the thread from time to time, otherwise the main thread @@ -332,14 +468,7 @@ protected: bool TestDestroy(); // exits from the current thread - can be called only from this thread - void Exit(void *exitcode = 0); - - // destructor is private - user code can't delete thread objects, they will - // auto-delete themselves (and thus must be always allocated on the heap). - // Use Delete() or Kill() instead. - // - // NB: derived classes dtors shouldn't be public neither! - virtual ~wxThread(); + void Exit(ExitCode exitcode = 0); // entry point for the thread - called by Run() and executes in the context // of this thread. @@ -353,10 +482,13 @@ private: friend class wxThreadInternal; // the (platform-dependent) thread class implementation - wxThreadInternal *p_internal; + wxThreadInternal *m_internal; // protects access to any methods of wxThreadInternal object wxCriticalSection m_critsect; + + // true if the thread is detached, false if it is joinable + bool m_isDetached; }; // ---------------------------------------------------------------------------- @@ -369,9 +501,10 @@ void WXDLLEXPORT wxMutexGuiLeave(); // macros for entering/leaving critical sections which may be used without // having to take them inside "#if wxUSE_THREADS" -#define wxENTER_CRIT_SECT(cs) (cs)->Enter() -#define wxLEAVE_CRIT_SECT(cs) (cs)->Leave() -#define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(*cs) +#define wxENTER_CRIT_SECT(cs) (cs).Enter() +#define wxLEAVE_CRIT_SECT(cs) (cs).Leave() +#define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs +#define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs) #else // !wxUSE_THREADS @@ -385,6 +518,7 @@ inline void WXDLLEXPORT wxMutexGuiLeave() { } // having to take them inside "#if wxUSE_THREADS" #define wxENTER_CRIT_SECT(cs) #define wxLEAVE_CRIT_SECT(cs) +#define wxCRIT_SECT_DECLARE(cs) #define wxCRIT_SECT_LOCKER(name, cs) #endif // wxUSE_THREADS @@ -430,6 +564,13 @@ public: // return TRUE if the main thread is waiting for some other to terminate: // wxApp then should block all "dangerous" messages extern bool WXDLLEXPORT wxIsWaitingForThread(); + + // implement wxCriticalSection using mutexes + inline wxCriticalSection::wxCriticalSection() : m_mutex() { } + inline wxCriticalSection::~wxCriticalSection() { } + + inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); } + inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); } #elif defined(__WXPM__) // unlock GUI if there are threads waiting for and lock it back when // there are no more of them - should be called periodically by the main @@ -462,3 +603,4 @@ public: #endif // wxUSE_THREADS #endif // __THREADH__ +