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1/////////////////////////////////////////////////////////////////////////////
2// Name: 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// RCS-ID: $Id$
9// Copyright: (c) Guilhem Lavaux
10// Licence: wxWindows licence
11/////////////////////////////////////////////////////////////////////////////
12
13#ifndef __THREADH__
14#define __THREADH__
15
16// ----------------------------------------------------------------------------
17// headers
18// ----------------------------------------------------------------------------
19
20// get the value of wxUSE_THREADS configuration flag
21#include "wx/setup.h"
22
23#if wxUSE_THREADS
24
25// only for wxUSE_THREADS - otherwise we'd get undefined symbols
26#ifdef __GNUG__
27 #pragma interface "thread.h"
28#endif
29
30// Windows headers define it
31#ifdef Yield
32 #undef Yield
33#endif
34
35#include "wx/module.h"
36
37// ----------------------------------------------------------------------------
38// constants
39// ----------------------------------------------------------------------------
40
41enum wxMutexError
42{
43 wxMUTEX_NO_ERROR = 0,
44 wxMUTEX_DEAD_LOCK, // Mutex has been already locked by THE CALLING thread
45 wxMUTEX_BUSY, // Mutex has been already locked by ONE thread
46 wxMUTEX_UNLOCKED,
47 wxMUTEX_MISC_ERROR
48};
49
50enum wxThreadError
51{
52 wxTHREAD_NO_ERROR = 0, // No error
53 wxTHREAD_NO_RESOURCE, // No resource left to create a new thread
54 wxTHREAD_RUNNING, // The thread is already running
55 wxTHREAD_NOT_RUNNING, // The thread isn't running
56 wxTHREAD_KILLED, // Thread we waited for had to be killed
57 wxTHREAD_MISC_ERROR // Some other error
58};
59
60enum wxThreadKind
61{
62 wxTHREAD_DETACHED,
63 wxTHREAD_JOINABLE
64};
65
66// defines the interval of priority
67enum
68{
69 WXTHREAD_MIN_PRIORITY = 0u,
70 WXTHREAD_DEFAULT_PRIORITY = 50u,
71 WXTHREAD_MAX_PRIORITY = 100u
72};
73
74// ----------------------------------------------------------------------------
75// A mutex object is a synchronization object whose state is set to signaled
76// when it is not owned by any thread, and nonsignaled when it is owned. Its
77// name comes from its usefulness in coordinating mutually-exclusive access to
78// a shared resource. Only one thread at a time can own a mutex object.
79// ----------------------------------------------------------------------------
80
81// you should consider wxMutexLocker whenever possible instead of directly
82// working with wxMutex class - it is safer
83class WXDLLEXPORT wxMutexInternal;
84class WXDLLEXPORT wxMutex
85{
86public:
87 // constructor & destructor
88 wxMutex();
89 ~wxMutex();
90
91 // Lock the mutex.
92 wxMutexError Lock();
93 // Try to lock the mutex: if it can't, returns immediately with an error.
94 wxMutexError TryLock();
95 // Unlock the mutex.
96 wxMutexError Unlock();
97
98 // Returns true if the mutex is locked.
99 bool IsLocked() const { return (m_locked > 0); }
100
101protected:
102 friend class wxCondition;
103
104 // no assignment operator nor copy ctor
105 wxMutex(const wxMutex&);
106 wxMutex& operator=(const wxMutex&);
107
108 int m_locked;
109 wxMutexInternal *m_internal;
110};
111
112// a helper class which locks the mutex in the ctor and unlocks it in the dtor:
113// this ensures that mutex is always unlocked, even if the function returns or
114// throws an exception before it reaches the end
115class WXDLLEXPORT wxMutexLocker
116{
117public:
118 // lock the mutex in the ctor
119 wxMutexLocker(wxMutex& mutex) : m_mutex(mutex)
120 { m_isOk = m_mutex.Lock() == wxMUTEX_NO_ERROR; }
121
122 // returns TRUE if mutex was successfully locked in ctor
123 bool IsOk() const
124 { return m_isOk; }
125
126 // unlock the mutex in dtor
127 ~wxMutexLocker()
128 { if ( IsOk() ) m_mutex.Unlock(); }
129
130private:
131 // no assignment operator nor copy ctor
132 wxMutexLocker(const wxMutexLocker&);
133 wxMutexLocker& operator=(const wxMutexLocker&);
134
135 bool m_isOk;
136 wxMutex& m_mutex;
137};
138
139// ----------------------------------------------------------------------------
140// Critical section: this is the same as mutex but is only visible to the
141// threads of the same process. For the platforms which don't have native
142// support for critical sections, they're implemented entirely in terms of
143// mutexes.
144//
145// NB: wxCriticalSection object does not allocate any memory in its ctor
146// which makes it possible to have static globals of this class
147// ----------------------------------------------------------------------------
148
149class WXDLLEXPORT wxCriticalSectionInternal;
150
151// in order to avoid any overhead under platforms where critical sections are
152// just mutexes make all wxCriticalSection class functions inline
153#if !defined(__WXMSW__) && !defined(__WXPM__)
154 #define WXCRITICAL_INLINE inline
155
156 #define wxCRITSECT_IS_MUTEX 1
157#else // MSW || OS2
158 #define WXCRITICAL_INLINE
159
160 #define wxCRITSECT_IS_MUTEX 0
161#endif // MSW/!MSW
162
163// you should consider wxCriticalSectionLocker whenever possible instead of
164// directly working with wxCriticalSection class - it is safer
165class WXDLLEXPORT wxCriticalSection
166{
167public:
168 // ctor & dtor
169 WXCRITICAL_INLINE wxCriticalSection();
170 WXCRITICAL_INLINE ~wxCriticalSection();
171
172 // enter the section (the same as locking a mutex)
173 WXCRITICAL_INLINE void Enter();
174 // leave the critical section (same as unlocking a mutex)
175 WXCRITICAL_INLINE void Leave();
176
177private:
178 // no assignment operator nor copy ctor
179 wxCriticalSection(const wxCriticalSection&);
180 wxCriticalSection& operator=(const wxCriticalSection&);
181
182#if wxCRITSECT_IS_MUTEX
183 wxMutex m_mutex;
184#elif defined(__WXMSW__)
185 // we can't allocate any memory in the ctor, so use placement new -
186 // unfortunately, we have to hardcode the sizeof() here because we can't
187 // include windows.h from this public header
188 char m_buffer[24];
189#elif !defined(__WXPM__)
190 wxCriticalSectionInternal *m_critsect;
191#else
192 // nothing for OS/2
193#endif // !Unix/Unix
194};
195
196// keep your preprocessor name space clean
197#undef WXCRITICAL_INLINE
198
199// wxCriticalSectionLocker is the same to critical sections as wxMutexLocker is
200// to th mutexes
201class WXDLLEXPORT wxCriticalSectionLocker
202{
203public:
204 inline wxCriticalSectionLocker(wxCriticalSection& critsect);
205 inline ~wxCriticalSectionLocker();
206
207private:
208 // no assignment operator nor copy ctor
209 wxCriticalSectionLocker(const wxCriticalSectionLocker&);
210 wxCriticalSectionLocker& operator=(const wxCriticalSectionLocker&);
211
212 wxCriticalSection& m_critsect;
213};
214
215// ----------------------------------------------------------------------------
216// Condition variable: allows to block the thread execution until something
217// happens (== condition is signaled)
218// ----------------------------------------------------------------------------
219
220class wxConditionInternal;
221class WXDLLEXPORT wxCondition
222{
223public:
224 // constructor & destructor
225 wxCondition();
226 ~wxCondition();
227
228 // wait until the condition is signaled
229 // waits indefinitely.
230 void Wait();
231 // waits until a signal is raised or the timeout elapses
232 bool Wait(unsigned long sec, unsigned long nsec);
233
234 // signal the condition
235 // wakes up one (and only one) of the waiting threads
236 void Signal();
237 // wakes up all threads waiting onthis condition
238 void Broadcast();
239
240private:
241 wxConditionInternal *m_internal;
242};
243
244// ----------------------------------------------------------------------------
245// Thread class
246// ----------------------------------------------------------------------------
247
248// there are two different kinds of threads: joinable and detached (default)
249// ones. Only joinable threads can return a return code and only detached
250// threads auto-delete themselves - the user should delete the joinable
251// threads manually.
252
253// NB: in the function descriptions the words "this thread" mean the thread
254// created by the wxThread object while "main thread" is the thread created
255// during the process initialization (a.k.a. the GUI thread)
256
257class wxThreadInternal;
258class WXDLLEXPORT wxThread
259{
260public:
261 // the return type for the thread function
262 typedef void *ExitCode;
263
264 // static functions
265 // Returns the wxThread object for the calling thread. NULL is returned
266 // if the caller is the main thread (but it's recommended to use
267 // IsMain() and only call This() for threads other than the main one
268 // because NULL is also returned on error). If the thread wasn't
269 // created with wxThread class, the returned value is undefined.
270 static wxThread *This();
271
272 // Returns true if current thread is the main thread.
273 static bool IsMain();
274
275 // Release the rest of our time slice leting the other threads run
276 static void Yield();
277
278 // Sleep during the specified period of time in milliseconds
279 //
280 // NB: at least under MSW worker threads can not call ::wxSleep()!
281 static void Sleep(unsigned long milliseconds);
282
283 // get the number of system CPUs - useful with SetConcurrency()
284 // (the "best" value for it is usually number of CPUs + 1)
285 //
286 // Returns -1 if unknown, number of CPUs otherwise
287 static int GetCPUCount();
288
289 // sets the concurrency level: this is, roughly, the number of threads
290 // the system tries to schedule to run in parallel. 0 means the
291 // default value (usually acceptable, but may not yield the best
292 // performance for this process)
293 //
294 // Returns TRUE on success, FALSE otherwise (if not implemented, for
295 // example)
296 static bool SetConcurrency(size_t level);
297
298 // constructor only creates the C++ thread object and doesn't create (or
299 // start) the real thread
300 wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
301
302 // functions that change the thread state: all these can only be called
303 // from _another_ thread (typically the thread that created this one, e.g.
304 // the main thread), not from the thread itself
305
306 // create a new thread and optionally set the stack size on
307 // platforms that support that - call Run() to start it
308 // (special cased for watcom which won't accept 0 default)
309
310#ifdef __WATCOMC__
311 wxThreadError Create(unsigned int stackSize = 10240);
312#else
313 wxThreadError Create(unsigned int stackSize = 0);
314#endif
315
316 // starts execution of the thread - from the moment Run() is called
317 // the execution of wxThread::Entry() may start at any moment, caller
318 // shouldn't suppose that it starts after (or before) Run() returns.
319 wxThreadError Run();
320
321 // stops the thread if it's running and deletes the wxThread object if
322 // this is a detached thread freeing its memory - otherwise (for
323 // joinable threads) you still need to delete wxThread object
324 // yourself.
325 //
326 // this function only works if the thread calls TestDestroy()
327 // periodically - the thread will only be deleted the next time it
328 // does it!
329 //
330 // will fill the rc pointer with the thread exit code if it's !NULL
331 wxThreadError Delete(ExitCode *rc = (ExitCode *)NULL);
332
333 // waits for a joinable thread to finish and returns its exit code
334 //
335 // Returns (ExitCode)-1 on error (for example, if the thread is not
336 // joinable)
337 ExitCode Wait();
338
339 // kills the thread without giving it any chance to clean up - should
340 // not be used in normal circumstances, use Delete() instead. It is a
341 // dangerous function that should only be used in the most extreme
342 // cases!
343 //
344 // The wxThread object is deleted by Kill() if the thread is
345 // detachable, but you still have to delete it manually for joinable
346 // threads.
347 wxThreadError Kill();
348
349 // pause a running thread: as Delete(), this only works if the thread
350 // calls TestDestroy() regularly
351 wxThreadError Pause();
352
353 // resume a paused thread
354 wxThreadError Resume();
355
356 // priority
357 // Sets the priority to "prio": see WXTHREAD_XXX_PRIORITY constants
358 //
359 // NB: the priority can only be set before the thread is created
360 void SetPriority(unsigned int prio);
361
362 // Get the current priority.
363 unsigned int GetPriority() const;
364
365 // thread status inquiries
366 // Returns true if the thread is alive: i.e. running or suspended
367 bool IsAlive() const;
368 // Returns true if the thread is running (not paused, not killed).
369 bool IsRunning() const;
370 // Returns true if the thread is suspended
371 bool IsPaused() const;
372
373 // is the thread of detached kind?
374 bool IsDetached() const { return m_isDetached; }
375
376 // Get the thread ID - a platform dependent number which uniquely
377 // identifies a thread inside a process
378#ifdef __VMS
379 unsigned long long GetId() const;
380#else
381 unsigned long GetId() const;
382#endif
383
384 // called when the thread exits - in the context of this thread
385 //
386 // NB: this function will not be called if the thread is Kill()ed
387 virtual void OnExit() { }
388
389 // dtor is public, but the detached threads should never be deleted - use
390 // Delete() instead (or leave the thread terminate by itself)
391 virtual ~wxThread();
392
393protected:
394 // Returns TRUE if the thread was asked to terminate: this function should
395 // be called by the thread from time to time, otherwise the main thread
396 // will be left forever in Delete()!
397 bool TestDestroy();
398
399 // exits from the current thread - can be called only from this thread
400 void Exit(ExitCode exitcode = 0);
401
402 // entry point for the thread - called by Run() and executes in the context
403 // of this thread.
404 virtual void *Entry() = 0;
405
406private:
407 // no copy ctor/assignment operator
408 wxThread(const wxThread&);
409 wxThread& operator=(const wxThread&);
410
411 friend class wxThreadInternal;
412
413 // the (platform-dependent) thread class implementation
414 wxThreadInternal *m_internal;
415
416 // protects access to any methods of wxThreadInternal object
417 wxCriticalSection m_critsect;
418
419 // true if the thread is detached, false if it is joinable
420 bool m_isDetached;
421};
422
423// ----------------------------------------------------------------------------
424// Automatic initialization
425// ----------------------------------------------------------------------------
426
427// GUI mutex handling.
428void WXDLLEXPORT wxMutexGuiEnter();
429void WXDLLEXPORT wxMutexGuiLeave();
430
431// macros for entering/leaving critical sections which may be used without
432// having to take them inside "#if wxUSE_THREADS"
433#define wxENTER_CRIT_SECT(cs) (cs).Enter()
434#define wxLEAVE_CRIT_SECT(cs) (cs).Leave()
435#define wxCRIT_SECT_DECLARE(cs) static wxCriticalSection cs
436#define wxCRIT_SECT_LOCKER(name, cs) wxCriticalSectionLocker name(cs)
437
438#else // !wxUSE_THREADS
439
440#include "wx/defs.h" // for WXDLLEXPORT
441
442// no thread support
443inline void WXDLLEXPORT wxMutexGuiEnter() { }
444inline void WXDLLEXPORT wxMutexGuiLeave() { }
445
446// macros for entering/leaving critical sections which may be used without
447// having to take them inside "#if wxUSE_THREADS"
448#define wxENTER_CRIT_SECT(cs)
449#define wxLEAVE_CRIT_SECT(cs)
450#define wxCRIT_SECT_DECLARE(cs)
451#define wxCRIT_SECT_LOCKER(name, cs)
452
453#endif // wxUSE_THREADS
454
455// automatically unlock GUI mutex in dtor
456class WXDLLEXPORT wxMutexGuiLocker
457{
458public:
459 wxMutexGuiLocker() { wxMutexGuiEnter(); }
460 ~wxMutexGuiLocker() { wxMutexGuiLeave(); }
461};
462
463// -----------------------------------------------------------------------------
464// implementation only until the end of file
465// -----------------------------------------------------------------------------
466
467#if wxUSE_THREADS
468
469#if defined(__WXMSW__)
470 // unlock GUI if there are threads waiting for and lock it back when
471 // there are no more of them - should be called periodically by the main
472 // thread
473 extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
474
475 // returns TRUE if the main thread has GUI lock
476 extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
477
478 // wakes up the main thread if it's sleeping inside ::GetMessage()
479 extern void WXDLLEXPORT wxWakeUpMainThread();
480
481 // return TRUE if the main thread is waiting for some other to terminate:
482 // wxApp then should block all "dangerous" messages
483 extern bool WXDLLEXPORT wxIsWaitingForThread();
484#elif defined(__WXMAC__)
485 extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
486
487 // returns TRUE if the main thread has GUI lock
488 extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
489
490 // wakes up the main thread if it's sleeping inside ::GetMessage()
491 extern void WXDLLEXPORT wxWakeUpMainThread();
492
493 // return TRUE if the main thread is waiting for some other to terminate:
494 // wxApp then should block all "dangerous" messages
495 extern bool WXDLLEXPORT wxIsWaitingForThread();
496
497 // implement wxCriticalSection using mutexes
498 inline wxCriticalSection::wxCriticalSection() { }
499 inline wxCriticalSection::~wxCriticalSection() { }
500
501 inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
502 inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
503#elif defined(__WXPM__)
504 // unlock GUI if there are threads waiting for and lock it back when
505 // there are no more of them - should be called periodically by the main
506 // thread
507 extern void WXDLLEXPORT wxMutexGuiLeaveOrEnter();
508
509 // returns TRUE if the main thread has GUI lock
510 extern bool WXDLLEXPORT wxGuiOwnedByMainThread();
511
512 // return TRUE if the main thread is waiting for some other to terminate:
513 // wxApp then should block all "dangerous" messages
514 extern bool WXDLLEXPORT wxIsWaitingForThread();
515
516#else // !MSW && !PM
517 // implement wxCriticalSection using mutexes
518 inline wxCriticalSection::wxCriticalSection() { }
519 inline wxCriticalSection::~wxCriticalSection() { }
520
521 inline void wxCriticalSection::Enter() { (void)m_mutex.Lock(); }
522 inline void wxCriticalSection::Leave() { (void)m_mutex.Unlock(); }
523#endif // MSW/!MSW
524
525 // we can define these inline functions now (they should be defined after
526 // wxCriticalSection::Enter/Leave)
527 inline
528 wxCriticalSectionLocker:: wxCriticalSectionLocker(wxCriticalSection& cs)
529 : m_critsect(cs) { m_critsect.Enter(); }
530 inline
531 wxCriticalSectionLocker::~wxCriticalSectionLocker() { m_critsect.Leave(); }
532#endif // wxUSE_THREADS
533
534#endif // __THREADH__
535
536// vi:sts=4:sw=4:et