X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/ed58dbeab64d18a0f869ea8e1610a0a88ad7b22c..ccdcde00d9ae27ca20ff6c3c9495918a0ec725aa:/include/wx/thread.h diff --git a/include/wx/thread.h b/include/wx/thread.h index fc734e6878..60f5c7c5c4 100644 --- a/include/wx/thread.h +++ b/include/wx/thread.h @@ -21,7 +21,8 @@ #include "wx/setup.h" #if wxUSE_THREADS -/* otherwise we get undefined references for non-thread case (KB)*/ + +// only for wxUSE_THREADS - otherwise we'd get undefined symbols #ifdef __GNUG__ #pragma interface "thread.h" #endif @@ -37,28 +38,38 @@ // constants // ---------------------------------------------------------------------------- -typedef enum +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 -} wxMutexError; - -typedef enum + 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 -} 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_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 -#define WXTHREAD_MIN_PRIORITY 0u -#define WXTHREAD_DEFAULT_PRIORITY 50u -#define WXTHREAD_MAX_PRIORITY 100u +enum +{ + WXTHREAD_MIN_PRIORITY = 0u, + WXTHREAD_DEFAULT_PRIORITY = 50u, + WXTHREAD_MAX_PRIORITY = 100u +}; // ---------------------------------------------------------------------------- // A mutex object is a synchronization object whose state is set to signaled @@ -69,6 +80,7 @@ typedef 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 { @@ -88,14 +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: @@ -129,16 +141,24 @@ private: // Critical section: this is the same as mutex but is only visible to the // threads of the same process. For the platforms which don't have native // support for critical sections, they're implemented entirely in terms of -// mutexes +// mutexes. +// +// NB: wxCriticalSection object does not allocate any memory in its ctor +// which makes it possible to have static globals of this class // ---------------------------------------------------------------------------- -// in order to avoid any overhead under !MSW make all wxCriticalSection class -// functions inline - but this can't be done under MSW -#if defined(__WXMSW__) || defined(__WXPM__) - class WXDLLEXPORT wxCriticalSectionInternal; - #define WXCRITICAL_INLINE -#else // !MSW +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__) #define WXCRITICAL_INLINE inline + + #define wxCRITSECT_IS_MUTEX 1 +#else // MSW || OS2 + #define WXCRITICAL_INLINE + + #define wxCRITSECT_IS_MUTEX 0 #endif // MSW/!MSW // you should consider wxCriticalSectionLocker whenever possible instead of @@ -160,11 +180,18 @@ private: wxCriticalSection(const wxCriticalSection&); wxCriticalSection& operator=(const wxCriticalSection&); -#if defined(__WXMSW__) || defined(__WXPM__) - wxCriticalSectionInternal *m_critsect; -#else // !MSW +#if wxCRITSECT_IS_MUTEX wxMutex m_mutex; -#endif // MSW/!MSW +#elif defined(__WXMSW__) + // we can't allocate any memory in the ctor, so use placement new - + // unfortunately, we have to hardcode the sizeof() here because we can't + // include windows.h from this public header + char m_buffer[24]; +#elif !defined(__WXPM__) + wxCriticalSectionInternal *m_critsect; +#else + // nothing for OS/2 +#endif // !Unix/Unix }; // keep your preprocessor name space clean @@ -175,10 +202,8 @@ private: class WXDLLEXPORT wxCriticalSectionLocker { public: - wxCriticalSectionLocker(wxCriticalSection& critsect) : m_critsect(critsect) - { m_critsect.Enter(); } - ~wxCriticalSectionLocker() - { m_critsect.Leave(); } + inline wxCriticalSectionLocker(wxCriticalSection& critsect); + inline ~wxCriticalSectionLocker(); private: // no assignment operator nor copy ctor @@ -189,40 +214,115 @@ 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 { 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(); + // 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 *p_internal; + wxConditionInternal *m_internal; }; // ---------------------------------------------------------------------------- -// Thread management class +// wxSemaphore: a counter limiting the number of threads concurrently accessing +// a shared resource // ---------------------------------------------------------------------------- -// FIXME Thread termination model is still unclear. Delete() should probably -// have a timeout after which the thread must be Kill()ed. +class WXDLLEXPORT wxSemaphoreInternal; +class WXDLLEXPORT wxSemaphore +{ +public: + // 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: + wxSemaphoreInternal *m_internal; +}; + +// ---------------------------------------------------------------------------- +// wxThread: class encpasulating a thread of execution +// ---------------------------------------------------------------------------- + +// 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 { @@ -249,34 +349,75 @@ 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 @@ -291,10 +432,6 @@ 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; @@ -303,11 +440,22 @@ 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 @@ -315,14 +463,7 @@ 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. @@ -336,10 +477,13 @@ 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; }; // ---------------------------------------------------------------------------- @@ -350,6 +494,13 @@ private: void WXDLLEXPORT wxMutexGuiEnter(); 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_DECLARE(cs) static wxCriticalSection cs +#define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs) + #else // !wxUSE_THREADS #include "wx/defs.h" // for WXDLLEXPORT @@ -358,6 +509,13 @@ void WXDLLEXPORT wxMutexGuiLeave(); inline void WXDLLEXPORT wxMutexGuiEnter() { } inline 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) +#define wxLEAVE_CRIT_SECT(cs) +#define wxCRIT_SECT_DECLARE(cs) +#define wxCRIT_SECT_LOCKER(name, cs) + #endif // wxUSE_THREADS // automatically unlock GUI mutex in dtor @@ -371,8 +529,10 @@ public: // ----------------------------------------------------------------------------- // implementation only until the end of file // ----------------------------------------------------------------------------- + #if wxUSE_THREADS -#if defined(__WXMSW__) || defined(__WXPM__) + +#if defined(__WXMSW__) // 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 // thread @@ -387,7 +547,39 @@ 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(); -#else // !MSW +#elif defined(__WXMAC__) + extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter(); + + // returns TRUE if the main thread has GUI lock + extern bool WXDLLEXPORT wxGuiOwnedByMainThread(); + + // wakes up the main thread if it's sleeping inside ::GetMessage() + extern void WXDLLEXPORT wxWakeUpMainThread(); + + // 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() { } + 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 + // thread + extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter(); + + // returns TRUE if the main thread has GUI lock + extern bool WXDLLEXPORT wxGuiOwnedByMainThread(); + + // return TRUE if the main thread is waiting for some other to terminate: + // wxApp then should block all "dangerous" messages + extern bool WXDLLEXPORT wxIsWaitingForThread(); + +#else // !MSW && !PM // implement wxCriticalSection using mutexes inline wxCriticalSection::wxCriticalSection() { } inline wxCriticalSection::~wxCriticalSection() { } @@ -395,6 +587,15 @@ public: inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); } inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); } #endif // MSW/!MSW + + // we can define these inline functions now (they should be defined after + // wxCriticalSection::Enter/Leave) + inline + wxCriticalSectionLocker:: wxCriticalSectionLocker(wxCriticalSection& cs) + : m_critsect(cs) { m_critsect.Enter(); } + inline + wxCriticalSectionLocker::~wxCriticalSectionLocker() { m_critsect.Leave(); } #endif // wxUSE_THREADS #endif // __THREADH__ +