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1/////////////////////////////////////////////////////////////////////////////
2// Name: wx/thread.h
3// Purpose: Thread API
4// Author: Guilhem Lavaux
5// Modified by: Vadim Zeitlin (modifications partly inspired by omnithreads
6// package from Olivetti & Oracle Research Laboratory)
7// Created: 04/13/98
8// Copyright: (c) Guilhem Lavaux
9// Licence: wxWindows licence
10/////////////////////////////////////////////////////////////////////////////
11
12#ifndef _WX_THREAD_H_
13#define _WX_THREAD_H_
14
15// ----------------------------------------------------------------------------
16// headers
17// ----------------------------------------------------------------------------
18
19// get the value of wxUSE_THREADS configuration flag
20#include "wx/defs.h"
21
22#if wxUSE_THREADS
23
24// ----------------------------------------------------------------------------
25// constants
26// ----------------------------------------------------------------------------
27
28enum wxMutexError
29{
30 wxMUTEX_NO_ERROR = 0, // operation completed successfully
31 wxMUTEX_INVALID, // mutex hasn't been initialized
32 wxMUTEX_DEAD_LOCK, // mutex is already locked by the calling thread
33 wxMUTEX_BUSY, // mutex is already locked by another thread
34 wxMUTEX_UNLOCKED, // attempt to unlock a mutex which is not locked
35 wxMUTEX_TIMEOUT, // LockTimeout() has timed out
36 wxMUTEX_MISC_ERROR // any other error
37};
38
39enum wxCondError
40{
41 wxCOND_NO_ERROR = 0,
42 wxCOND_INVALID,
43 wxCOND_TIMEOUT, // WaitTimeout() has timed out
44 wxCOND_MISC_ERROR
45};
46
47enum wxSemaError
48{
49 wxSEMA_NO_ERROR = 0,
50 wxSEMA_INVALID, // semaphore hasn't been initialized successfully
51 wxSEMA_BUSY, // returned by TryWait() if Wait() would block
52 wxSEMA_TIMEOUT, // returned by WaitTimeout()
53 wxSEMA_OVERFLOW, // Post() would increase counter past the max
54 wxSEMA_MISC_ERROR
55};
56
57enum wxThreadError
58{
59 wxTHREAD_NO_ERROR = 0, // No error
60 wxTHREAD_NO_RESOURCE, // No resource left to create a new thread
61 wxTHREAD_RUNNING, // The thread is already running
62 wxTHREAD_NOT_RUNNING, // The thread isn't running
63 wxTHREAD_KILLED, // Thread we waited for had to be killed
64 wxTHREAD_MISC_ERROR // Some other error
65};
66
67enum wxThreadKind
68{
69 wxTHREAD_DETACHED,
70 wxTHREAD_JOINABLE
71};
72
73enum wxThreadWait
74{
75 wxTHREAD_WAIT_BLOCK,
76 wxTHREAD_WAIT_YIELD, // process events while waiting; MSW only
77
78 // For compatibility reasons we use wxTHREAD_WAIT_YIELD by default as this
79 // was the default behaviour of wxMSW 2.8 but it should be avoided as it's
80 // dangerous and not portable.
81#if WXWIN_COMPATIBILITY_2_8
82 wxTHREAD_WAIT_DEFAULT = wxTHREAD_WAIT_YIELD
83#else
84 wxTHREAD_WAIT_DEFAULT = wxTHREAD_WAIT_BLOCK
85#endif
86};
87
88// Obsolete synonyms for wxPRIORITY_XXX for backwards compatibility-only
89enum
90{
91 WXTHREAD_MIN_PRIORITY = wxPRIORITY_MIN,
92 WXTHREAD_DEFAULT_PRIORITY = wxPRIORITY_DEFAULT,
93 WXTHREAD_MAX_PRIORITY = wxPRIORITY_MAX
94};
95
96// There are 2 types of mutexes: normal mutexes and recursive ones. The attempt
97// to lock a normal mutex by a thread which already owns it results in
98// undefined behaviour (it always works under Windows, it will almost always
99// result in a deadlock under Unix). Locking a recursive mutex in such
100// situation always succeeds and it must be unlocked as many times as it has
101// been locked.
102//
103// However recursive mutexes have several important drawbacks: first, in the
104// POSIX implementation, they're less efficient. Second, and more importantly,
105// they CAN NOT BE USED WITH CONDITION VARIABLES under Unix! Using them with
106// wxCondition will work under Windows and some Unices (notably Linux) but will
107// deadlock under other Unix versions (e.g. Solaris). As it might be difficult
108// to ensure that a recursive mutex is not used with wxCondition, it is a good
109// idea to avoid using recursive mutexes at all. Also, the last problem with
110// them is that some (older) Unix versions don't support this at all -- which
111// results in a configure warning when building and a deadlock when using them.
112enum wxMutexType
113{
114 // normal mutex: try to always use this one
115 wxMUTEX_DEFAULT,
116
117 // recursive mutex: don't use these ones with wxCondition
118 wxMUTEX_RECURSIVE
119};
120
121// forward declarations
122class WXDLLIMPEXP_FWD_BASE wxThreadHelper;
123class WXDLLIMPEXP_FWD_BASE wxConditionInternal;
124class WXDLLIMPEXP_FWD_BASE wxMutexInternal;
125class WXDLLIMPEXP_FWD_BASE wxSemaphoreInternal;
126class WXDLLIMPEXP_FWD_BASE wxThreadInternal;
127
128// ----------------------------------------------------------------------------
129// A mutex object is a synchronization object whose state is set to signaled
130// when it is not owned by any thread, and nonsignaled when it is owned. Its
131// name comes from its usefulness in coordinating mutually-exclusive access to
132// a shared resource. Only one thread at a time can own a mutex object.
133// ----------------------------------------------------------------------------
134
135// you should consider wxMutexLocker whenever possible instead of directly
136// working with wxMutex class - it is safer
137class WXDLLIMPEXP_BASE wxMutex
138{
139public:
140 // constructor & destructor
141 // ------------------------
142
143 // create either default (always safe) or recursive mutex
144 wxMutex(wxMutexType mutexType = wxMUTEX_DEFAULT);
145
146 // destroys the mutex kernel object
147 ~wxMutex();
148
149 // test if the mutex has been created successfully
150 bool IsOk() const;
151
152 // mutex operations
153 // ----------------
154
155 // Lock the mutex, blocking on it until it is unlocked by the other thread.
156 // The result of locking a mutex already locked by the current thread
157 // depend on the mutex type.
158 //
159 // The caller must call Unlock() later if Lock() returned wxMUTEX_NO_ERROR.
160 wxMutexError Lock();
161
162 // Same as Lock() but return wxMUTEX_TIMEOUT if the mutex can't be locked
163 // during the given number of milliseconds
164 wxMutexError LockTimeout(unsigned long ms);
165
166 // Try to lock the mutex: if it is currently locked, return immediately
167 // with an error. Otherwise the caller must call Unlock().
168 wxMutexError TryLock();
169
170 // Unlock the mutex. It is an error to unlock an already unlocked mutex
171 wxMutexError Unlock();
172
173protected:
174 wxMutexInternal *m_internal;
175
176 friend class wxConditionInternal;
177
178 wxDECLARE_NO_COPY_CLASS(wxMutex);
179};
180
181// a helper class which locks the mutex in the ctor and unlocks it in the dtor:
182// this ensures that mutex is always unlocked, even if the function returns or
183// throws an exception before it reaches the end
184class WXDLLIMPEXP_BASE wxMutexLocker
185{
186public:
187 // lock the mutex in the ctor
188 wxMutexLocker(wxMutex& mutex)
189 : m_isOk(false), m_mutex(mutex)
190 { m_isOk = ( m_mutex.Lock() == wxMUTEX_NO_ERROR ); }
191
192 // returns true if mutex was successfully locked in ctor
193 bool IsOk() const
194 { return m_isOk; }
195
196 // unlock the mutex in dtor
197 ~wxMutexLocker()
198 { if ( IsOk() ) m_mutex.Unlock(); }
199
200private:
201 // no assignment operator nor copy ctor
202 wxMutexLocker(const wxMutexLocker&);
203 wxMutexLocker& operator=(const wxMutexLocker&);
204
205 bool m_isOk;
206 wxMutex& m_mutex;
207};
208
209// ----------------------------------------------------------------------------
210// Critical section: this is the same as mutex but is only visible to the
211// threads of the same process. For the platforms which don't have native
212// support for critical sections, they're implemented entirely in terms of
213// mutexes.
214//
215// NB: wxCriticalSection object does not allocate any memory in its ctor
216// which makes it possible to have static globals of this class
217// ----------------------------------------------------------------------------
218
219// in order to avoid any overhead under platforms where critical sections are
220// just mutexes make all wxCriticalSection class functions inline
221#if !defined(__WINDOWS__)
222 #define wxCRITSECT_IS_MUTEX 1
223
224 #define wxCRITSECT_INLINE WXEXPORT inline
225#else // MSW
226 #define wxCRITSECT_IS_MUTEX 0
227
228 #define wxCRITSECT_INLINE
229#endif // MSW/!MSW
230
231enum wxCriticalSectionType
232{
233 // recursive critical section
234 wxCRITSEC_DEFAULT,
235
236 // non-recursive critical section
237 wxCRITSEC_NON_RECURSIVE
238};
239
240// you should consider wxCriticalSectionLocker whenever possible instead of
241// directly working with wxCriticalSection class - it is safer
242class WXDLLIMPEXP_BASE wxCriticalSection
243{
244public:
245 // ctor & dtor
246 wxCRITSECT_INLINE wxCriticalSection( wxCriticalSectionType critSecType = wxCRITSEC_DEFAULT );
247 wxCRITSECT_INLINE ~wxCriticalSection();
248 // enter the section (the same as locking a mutex)
249 wxCRITSECT_INLINE void Enter();
250
251 // try to enter the section (the same as trying to lock a mutex)
252 wxCRITSECT_INLINE bool TryEnter();
253
254 // leave the critical section (same as unlocking a mutex)
255 wxCRITSECT_INLINE void Leave();
256
257private:
258#if wxCRITSECT_IS_MUTEX
259 wxMutex m_mutex;
260#elif defined(__WINDOWS__)
261 // we can't allocate any memory in the ctor, so use placement new -
262 // unfortunately, we have to hardcode the sizeof() here because we can't
263 // include windows.h from this public header and we also have to use the
264 // union to force the correct (i.e. maximal) alignment
265 //
266 // if CRITICAL_SECTION size changes in Windows, you'll get an assert from
267 // thread.cpp and will need to increase the buffer size
268#ifdef __WIN64__
269 typedef char wxCritSectBuffer[40];
270#else // __WIN32__
271 typedef char wxCritSectBuffer[24];
272#endif
273 union
274 {
275 unsigned long m_dummy1;
276 void *m_dummy2;
277
278 wxCritSectBuffer m_buffer;
279 };
280#endif // Unix&OS2/Win32
281
282 wxDECLARE_NO_COPY_CLASS(wxCriticalSection);
283};
284
285#if wxCRITSECT_IS_MUTEX
286 // implement wxCriticalSection using mutexes
287 inline wxCriticalSection::wxCriticalSection( wxCriticalSectionType critSecType )
288 : m_mutex( critSecType == wxCRITSEC_DEFAULT ? wxMUTEX_RECURSIVE : wxMUTEX_DEFAULT ) { }
289 inline wxCriticalSection::~wxCriticalSection() { }
290
291 inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
292 inline bool wxCriticalSection::TryEnter() { return m_mutex.TryLock() == wxMUTEX_NO_ERROR; }
293 inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
294#endif // wxCRITSECT_IS_MUTEX
295
296#undef wxCRITSECT_INLINE
297#undef wxCRITSECT_IS_MUTEX
298
299// wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
300// to mutexes
301class WXDLLIMPEXP_BASE wxCriticalSectionLocker
302{
303public:
304 wxCriticalSectionLocker(wxCriticalSection& cs)
305 : m_critsect(cs)
306 {
307 m_critsect.Enter();
308 }
309
310 ~wxCriticalSectionLocker()
311 {
312 m_critsect.Leave();
313 }
314
315private:
316 wxCriticalSection& m_critsect;
317
318 wxDECLARE_NO_COPY_CLASS(wxCriticalSectionLocker);
319};
320
321// ----------------------------------------------------------------------------
322// wxCondition models a POSIX condition variable which allows one (or more)
323// thread(s) to wait until some condition is fulfilled
324// ----------------------------------------------------------------------------
325
326class WXDLLIMPEXP_BASE wxCondition
327{
328public:
329 // Each wxCondition object is associated with a (single) wxMutex object.
330 // The mutex object MUST be locked before calling Wait()
331 wxCondition(wxMutex& mutex);
332
333 // dtor is not virtual, don't use this class polymorphically
334 ~wxCondition();
335
336 // return true if the condition has been created successfully
337 bool IsOk() const;
338
339 // NB: the associated mutex MUST be locked beforehand by the calling thread
340 //
341 // it atomically releases the lock on the associated mutex
342 // and starts waiting to be woken up by a Signal()/Broadcast()
343 // once its signaled, then it will wait until it can reacquire
344 // the lock on the associated mutex object, before returning.
345 wxCondError Wait();
346
347 // std::condition_variable-like variant that evaluates the associated condition
348 template<typename Functor>
349 wxCondError Wait(const Functor& predicate)
350 {
351 while ( !predicate() )
352 {
353 wxCondError e = Wait();
354 if ( e != wxCOND_NO_ERROR )
355 return e;
356 }
357 return wxCOND_NO_ERROR;
358 }
359
360 // exactly as Wait() except that it may also return if the specified
361 // timeout elapses even if the condition hasn't been signalled: in this
362 // case, the return value is wxCOND_TIMEOUT, otherwise (i.e. in case of a
363 // normal return) it is wxCOND_NO_ERROR.
364 //
365 // the timeout parameter specifies an interval that needs to be waited for
366 // in milliseconds
367 wxCondError WaitTimeout(unsigned long milliseconds);
368
369 // NB: the associated mutex may or may not be locked by the calling thread
370 //
371 // this method unblocks one thread if any are blocking on the condition.
372 // if no thread is blocking in Wait(), then the signal is NOT remembered
373 // The thread which was blocking on Wait() will then reacquire the lock
374 // on the associated mutex object before returning
375 wxCondError Signal();
376
377 // NB: the associated mutex may or may not be locked by the calling thread
378 //
379 // this method unblocks all threads if any are blocking on the condition.
380 // if no thread is blocking in Wait(), then the signal is NOT remembered
381 // The threads which were blocking on Wait() will then reacquire the lock
382 // on the associated mutex object before returning.
383 wxCondError Broadcast();
384
385
386#if WXWIN_COMPATIBILITY_2_6
387 // deprecated version, don't use
388 wxDEPRECATED( bool Wait(unsigned long milliseconds) );
389#endif // WXWIN_COMPATIBILITY_2_6
390
391private:
392 wxConditionInternal *m_internal;
393
394 wxDECLARE_NO_COPY_CLASS(wxCondition);
395};
396
397#if WXWIN_COMPATIBILITY_2_6
398 inline bool wxCondition::Wait(unsigned long milliseconds)
399 { return WaitTimeout(milliseconds) == wxCOND_NO_ERROR; }
400#endif // WXWIN_COMPATIBILITY_2_6
401
402// ----------------------------------------------------------------------------
403// wxSemaphore: a counter limiting the number of threads concurrently accessing
404// a shared resource
405// ----------------------------------------------------------------------------
406
407class WXDLLIMPEXP_BASE wxSemaphore
408{
409public:
410 // specifying a maxcount of 0 actually makes wxSemaphore behave as if there
411 // is no upper limit, if maxcount is 1 the semaphore behaves as a mutex
412 wxSemaphore( int initialcount = 0, int maxcount = 0 );
413
414 // dtor is not virtual, don't use this class polymorphically
415 ~wxSemaphore();
416
417 // return true if the semaphore has been created successfully
418 bool IsOk() const;
419
420 // wait indefinitely, until the semaphore count goes beyond 0
421 // and then decrement it and return (this method might have been called
422 // Acquire())
423 wxSemaError Wait();
424
425 // same as Wait(), but does not block, returns wxSEMA_NO_ERROR if
426 // successful and wxSEMA_BUSY if the count is currently zero
427 wxSemaError TryWait();
428
429 // same as Wait(), but as a timeout limit, returns wxSEMA_NO_ERROR if the
430 // semaphore was acquired and wxSEMA_TIMEOUT if the timeout has elapsed
431 wxSemaError WaitTimeout(unsigned long milliseconds);
432
433 // increments the semaphore count and signals one of the waiting threads
434 wxSemaError Post();
435
436private:
437 wxSemaphoreInternal *m_internal;
438
439 wxDECLARE_NO_COPY_CLASS(wxSemaphore);
440};
441
442// ----------------------------------------------------------------------------
443// wxThread: class encapsulating a thread of execution
444// ----------------------------------------------------------------------------
445
446// there are two different kinds of threads: joinable and detached (default)
447// ones. Only joinable threads can return a return code and only detached
448// threads auto-delete themselves - the user should delete the joinable
449// threads manually.
450
451// NB: in the function descriptions the words "this thread" mean the thread
452// created by the wxThread object while "main thread" is the thread created
453// during the process initialization (a.k.a. the GUI thread)
454
455// On VMS thread pointers are 64 bits (also needed for other systems???
456#ifdef __VMS
457 typedef unsigned long long wxThreadIdType;
458#else
459 typedef unsigned long wxThreadIdType;
460#endif
461
462class WXDLLIMPEXP_BASE wxThread
463{
464public:
465 // the return type for the thread function
466 typedef void *ExitCode;
467
468 // static functions
469 // Returns the wxThread object for the calling thread. NULL is returned
470 // if the caller is the main thread (but it's recommended to use
471 // IsMain() and only call This() for threads other than the main one
472 // because NULL is also returned on error). If the thread wasn't
473 // created with wxThread class, the returned value is undefined.
474 static wxThread *This();
475
476 // Returns true if current thread is the main thread.
477 //
478 // Notice that it also returns true if main thread id hadn't been
479 // initialized yet on the assumption that it's too early in wx startup
480 // process for any other threads to have been created in this case.
481 static bool IsMain()
482 {
483 return !ms_idMainThread || GetCurrentId() == ms_idMainThread;
484 }
485
486 // Return the main thread id
487 static wxThreadIdType GetMainId() { return ms_idMainThread; }
488
489 // Release the rest of our time slice letting the other threads run
490 static void Yield();
491
492 // Sleep during the specified period of time in milliseconds
493 //
494 // This is the same as wxMilliSleep().
495 static void Sleep(unsigned long milliseconds);
496
497 // get the number of system CPUs - useful with SetConcurrency()
498 // (the "best" value for it is usually number of CPUs + 1)
499 //
500 // Returns -1 if unknown, number of CPUs otherwise
501 static int GetCPUCount();
502
503 // Get the platform specific thread ID and return as a long. This
504 // can be used to uniquely identify threads, even if they are not
505 // wxThreads. This is used by wxPython.
506 static wxThreadIdType GetCurrentId();
507
508 // sets the concurrency level: this is, roughly, the number of threads
509 // the system tries to schedule to run in parallel. 0 means the
510 // default value (usually acceptable, but may not yield the best
511 // performance for this process)
512 //
513 // Returns true on success, false otherwise (if not implemented, for
514 // example)
515 static bool SetConcurrency(size_t level);
516
517 // constructor only creates the C++ thread object and doesn't create (or
518 // start) the real thread
519 wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
520
521 // functions that change the thread state: all these can only be called
522 // from _another_ thread (typically the thread that created this one, e.g.
523 // the main thread), not from the thread itself
524
525 // create a new thread and optionally set the stack size on
526 // platforms that support that - call Run() to start it
527 // (special cased for watcom which won't accept 0 default)
528
529 wxThreadError Create(unsigned int stackSize = 0);
530
531 // starts execution of the thread - from the moment Run() is called
532 // the execution of wxThread::Entry() may start at any moment, caller
533 // shouldn't suppose that it starts after (or before) Run() returns.
534 wxThreadError Run();
535
536 // stops the thread if it's running and deletes the wxThread object if
537 // this is a detached thread freeing its memory - otherwise (for
538 // joinable threads) you still need to delete wxThread object
539 // yourself.
540 //
541 // this function only works if the thread calls TestDestroy()
542 // periodically - the thread will only be deleted the next time it
543 // does it!
544 //
545 // will fill the rc pointer with the thread exit code if it's !NULL
546 wxThreadError Delete(ExitCode *rc = NULL,
547 wxThreadWait waitMode = wxTHREAD_WAIT_DEFAULT);
548
549 // waits for a joinable thread to finish and returns its exit code
550 //
551 // Returns (ExitCode)-1 on error (for example, if the thread is not
552 // joinable)
553 ExitCode Wait(wxThreadWait waitMode = wxTHREAD_WAIT_DEFAULT);
554
555 // kills the thread without giving it any chance to clean up - should
556 // not be used under normal circumstances, use Delete() instead.
557 // It is a dangerous function that should only be used in the most
558 // extreme cases!
559 //
560 // The wxThread object is deleted by Kill() if the thread is
561 // detachable, but you still have to delete it manually for joinable
562 // threads.
563 wxThreadError Kill();
564
565 // pause a running thread: as Delete(), this only works if the thread
566 // calls TestDestroy() regularly
567 wxThreadError Pause();
568
569 // resume a paused thread
570 wxThreadError Resume();
571
572 // priority
573 // Sets the priority to "prio" which must be in 0..100 range (see
574 // also wxPRIORITY_XXX constants).
575 //
576 // NB: the priority can only be set before the thread is created
577 void SetPriority(unsigned int prio);
578
579 // Get the current priority.
580 unsigned int GetPriority() const;
581
582 // thread status inquiries
583 // Returns true if the thread is alive: i.e. running or suspended
584 bool IsAlive() const;
585 // Returns true if the thread is running (not paused, not killed).
586 bool IsRunning() const;
587 // Returns true if the thread is suspended
588 bool IsPaused() const;
589
590 // is the thread of detached kind?
591 bool IsDetached() const { return m_isDetached; }
592
593 // Get the thread ID - a platform dependent number which uniquely
594 // identifies a thread inside a process
595 wxThreadIdType GetId() const;
596
597 wxThreadKind GetKind() const
598 { return m_isDetached ? wxTHREAD_DETACHED : wxTHREAD_JOINABLE; }
599
600 // Returns true if the thread was asked to terminate: this function should
601 // be called by the thread from time to time, otherwise the main thread
602 // will be left forever in Delete()!
603 virtual bool TestDestroy();
604
605 // dtor is public, but the detached threads should never be deleted - use
606 // Delete() instead (or leave the thread terminate by itself)
607 virtual ~wxThread();
608
609protected:
610 // exits from the current thread - can be called only from this thread
611 void Exit(ExitCode exitcode = 0);
612
613 // entry point for the thread - called by Run() and executes in the context
614 // of this thread.
615 virtual void *Entry() = 0;
616
617
618 // Callbacks which may be overridden by the derived class to perform some
619 // specific actions when the thread is deleted or killed. By default they
620 // do nothing.
621
622 // This one is called by Delete() before actually deleting the thread and
623 // is executed in the context of the thread that called Delete().
624 virtual void OnDelete() {}
625
626 // This one is called by Kill() before killing the thread and is executed
627 // in the context of the thread that called Kill().
628 virtual void OnKill() {}
629
630private:
631 // no copy ctor/assignment operator
632 wxThread(const wxThread&);
633 wxThread& operator=(const wxThread&);
634
635 // called when the thread exits - in the context of this thread
636 //
637 // NB: this function will not be called if the thread is Kill()ed
638 virtual void OnExit() { }
639
640 friend class wxThreadInternal;
641 friend class wxThreadModule;
642
643
644 // the main thread identifier, should be set on startup
645 static wxThreadIdType ms_idMainThread;
646
647 // the (platform-dependent) thread class implementation
648 wxThreadInternal *m_internal;
649
650 // protects access to any methods of wxThreadInternal object
651 wxCriticalSection m_critsect;
652
653 // true if the thread is detached, false if it is joinable
654 bool m_isDetached;
655};
656
657// wxThreadHelperThread class
658// --------------------------
659
660class WXDLLIMPEXP_BASE wxThreadHelperThread : public wxThread
661{
662public:
663 // constructor only creates the C++ thread object and doesn't create (or
664 // start) the real thread
665 wxThreadHelperThread(wxThreadHelper& owner, wxThreadKind kind)
666 : wxThread(kind), m_owner(owner)
667 { }
668
669protected:
670 // entry point for the thread -- calls Entry() in owner.
671 virtual void *Entry();
672
673private:
674 // the owner of the thread
675 wxThreadHelper& m_owner;
676
677 // no copy ctor/assignment operator
678 wxThreadHelperThread(const wxThreadHelperThread&);
679 wxThreadHelperThread& operator=(const wxThreadHelperThread&);
680};
681
682// ----------------------------------------------------------------------------
683// wxThreadHelper: this class implements the threading logic to run a
684// background task in another object (such as a window). It is a mix-in: just
685// derive from it to implement a threading background task in your class.
686// ----------------------------------------------------------------------------
687
688class WXDLLIMPEXP_BASE wxThreadHelper
689{
690private:
691 void KillThread()
692 {
693 // If wxThreadHelperThread is detached and is about to finish, it will
694 // set m_thread to NULL so don't delete it then.
695 // But if KillThread is called before wxThreadHelperThread (in detached mode)
696 // sets it to NULL, then the thread object still exists and can be killed
697 wxCriticalSectionLocker locker(m_critSection);
698
699 if ( m_thread )
700 {
701 m_thread->Kill();
702
703 if ( m_kind == wxTHREAD_JOINABLE )
704 delete m_thread;
705
706 m_thread = NULL;
707 }
708 }
709
710public:
711 // constructor only initializes m_thread to NULL
712 wxThreadHelper(wxThreadKind kind = wxTHREAD_JOINABLE)
713 : m_thread(NULL), m_kind(kind) { }
714
715 // destructor deletes m_thread
716 virtual ~wxThreadHelper() { KillThread(); }
717
718#if WXWIN_COMPATIBILITY_2_8
719 wxDEPRECATED( wxThreadError Create(unsigned int stackSize = 0) );
720#endif
721
722 // create a new thread (and optionally set the stack size on platforms that
723 // support/need that), call Run() to start it
724 wxThreadError CreateThread(wxThreadKind kind = wxTHREAD_JOINABLE,
725 unsigned int stackSize = 0)
726 {
727 KillThread();
728
729 m_kind = kind;
730 m_thread = new wxThreadHelperThread(*this, m_kind);
731
732 return m_thread->Create(stackSize);
733 }
734
735 // entry point for the thread - called by Run() and executes in the context
736 // of this thread.
737 virtual void *Entry() = 0;
738
739 // returns a pointer to the thread which can be used to call Run()
740 wxThread *GetThread() const
741 {
742 wxCriticalSectionLocker locker((wxCriticalSection&)m_critSection);
743
744 wxThread* thread = m_thread;
745
746 return thread;
747 }
748
749protected:
750 wxThread *m_thread;
751 wxThreadKind m_kind;
752 wxCriticalSection m_critSection; // To guard the m_thread variable
753
754 friend class wxThreadHelperThread;
755};
756
757#if WXWIN_COMPATIBILITY_2_8
758inline wxThreadError wxThreadHelper::Create(unsigned int stackSize)
759{ return CreateThread(m_kind, stackSize); }
760#endif
761
762// call Entry() in owner, put it down here to avoid circular declarations
763inline void *wxThreadHelperThread::Entry()
764{
765 void * const result = m_owner.Entry();
766
767 wxCriticalSectionLocker locker(m_owner.m_critSection);
768
769 // Detached thread will be deleted after returning, so make sure
770 // wxThreadHelper::GetThread will not return an invalid pointer.
771 // And that wxThreadHelper::KillThread will not try to kill
772 // an already deleted thread
773 if ( m_owner.m_kind == wxTHREAD_DETACHED )
774 m_owner.m_thread = NULL;
775
776 return result;
777}
778
779// ----------------------------------------------------------------------------
780// Automatic initialization
781// ----------------------------------------------------------------------------
782
783// GUI mutex handling.
784void WXDLLIMPEXP_BASE wxMutexGuiEnter();
785void WXDLLIMPEXP_BASE wxMutexGuiLeave();
786
787// macros for entering/leaving critical sections which may be used without
788// having to take them inside "#if wxUSE_THREADS"
789#define wxENTER_CRIT_SECT(cs) (cs).Enter()
790#define wxLEAVE_CRIT_SECT(cs) (cs).Leave()
791#define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
792#define wxCRIT_SECT_DECLARE_MEMBER(cs) wxCriticalSection cs
793#define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs)
794
795// function for checking if we're in the main thread which may be used whether
796// wxUSE_THREADS is 0 or 1
797inline bool wxIsMainThread() { return wxThread::IsMain(); }
798
799#else // !wxUSE_THREADS
800
801// no thread support
802inline void wxMutexGuiEnter() { }
803inline void wxMutexGuiLeave() { }
804
805// macros for entering/leaving critical sections which may be used without
806// having to take them inside "#if wxUSE_THREADS"
807// (the implementation uses dummy structs to force semicolon after the macro;
808// also notice that Watcom doesn't like declaring a struct as a member so we
809// need to actually define it in wxCRIT_SECT_DECLARE_MEMBER)
810#define wxENTER_CRIT_SECT(cs) do {} while (0)
811#define wxLEAVE_CRIT_SECT(cs) do {} while (0)
812#define wxCRIT_SECT_DECLARE(cs) struct wxDummyCS##cs
813#define wxCRIT_SECT_DECLARE_MEMBER(cs) struct wxDummyCSMember##cs { }
814#define wxCRIT_SECT_LOCKER(name, cs) struct wxDummyCSLocker##name
815
816// if there is only one thread, it is always the main one
817inline bool wxIsMainThread() { return true; }
818
819#endif // wxUSE_THREADS/!wxUSE_THREADS
820
821// mark part of code as being a critical section: this macro declares a
822// critical section with the given name and enters it immediately and leaves
823// it at the end of the current scope
824//
825// example:
826//
827// int Count()
828// {
829// static int s_counter = 0;
830//
831// wxCRITICAL_SECTION(counter);
832//
833// return ++s_counter;
834// }
835//
836// this function is MT-safe in presence of the threads but there is no
837// overhead when the library is compiled without threads
838#define wxCRITICAL_SECTION(name) \
839 wxCRIT_SECT_DECLARE(s_cs##name); \
840 wxCRIT_SECT_LOCKER(cs##name##Locker, s_cs##name)
841
842// automatically lock GUI mutex in ctor and unlock it in dtor
843class WXDLLIMPEXP_BASE wxMutexGuiLocker
844{
845public:
846 wxMutexGuiLocker() { wxMutexGuiEnter(); }
847 ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
848};
849
850// -----------------------------------------------------------------------------
851// implementation only until the end of file
852// -----------------------------------------------------------------------------
853
854#if wxUSE_THREADS
855
856#if defined(__WINDOWS__) || defined(__OS2__) || defined(__EMX__) || defined(__DARWIN__)
857 // unlock GUI if there are threads waiting for and lock it back when
858 // there are no more of them - should be called periodically by the main
859 // thread
860 extern void WXDLLIMPEXP_BASE wxMutexGuiLeaveOrEnter();
861
862 // returns true if the main thread has GUI lock
863 extern bool WXDLLIMPEXP_BASE wxGuiOwnedByMainThread();
864
865 // wakes up the main thread if it's sleeping inside ::GetMessage()
866 extern void WXDLLIMPEXP_BASE wxWakeUpMainThread();
867
868#ifndef __DARWIN__
869 // return true if the main thread is waiting for some other to terminate:
870 // wxApp then should block all "dangerous" messages
871 extern bool WXDLLIMPEXP_BASE wxIsWaitingForThread();
872#endif
873#endif // MSW, OS/2
874
875#endif // wxUSE_THREADS
876
877#endif // _WX_THREAD_H_