1 /* Copyright  (C) 2010-2020 The RetroArch team
2  *
3  * ---------------------------------------------------------------------------------------
4  * The following license statement only applies to this file (rthreads.c).
5  * ---------------------------------------------------------------------------------------
6  *
7  * Permission is hereby granted, free of charge,
8  * to any person obtaining a copy of this software and associated documentation files (the "Software"),
9  * to deal in the Software without restriction, including without limitation the rights to
10  * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
11  * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
16  * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18  * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
19  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21  */
22 
23 #ifdef __unix__
24 #ifndef __sun__
25 #define _POSIX_C_SOURCE 199309
26 #endif
27 #endif
28 
29 #include <stdlib.h>
30 #include <string.h>
31 
32 #include <boolean.h>
33 #include <rthreads/rthreads.h>
34 
35 /* with RETRO_WIN32_USE_PTHREADS, pthreads can be used even on win32. Maybe only supported in MSVC>=2005  */
36 
37 #if defined(_WIN32) && !defined(RETRO_WIN32_USE_PTHREADS)
38 #define USE_WIN32_THREADS
39 #ifdef _XBOX
40 #include <xtl.h>
41 #else
42 #define WIN32_LEAN_AND_MEAN
43 #ifndef _WIN32_WINNT
44 #define _WIN32_WINNT 0x0500 /*_WIN32_WINNT_WIN2K */
45 #endif
46 #include <windows.h>
47 #include <mmsystem.h>
48 #endif
49 #elif defined(GEKKO)
50 #include "gx_pthread.h"
51 #elif defined(_3DS)
52 #include "ctr_pthread.h"
53 #else
54 #include <pthread.h>
55 #include <time.h>
56 #endif
57 
58 #if defined(VITA) || defined(BSD) || defined(ORBIS)
59 #include <sys/time.h>
60 #endif
61 
62 #ifdef __MACH__
63 #include <mach/clock.h>
64 #include <mach/mach.h>
65 #endif
66 
67 #include <sys/time.h>
68 
69 struct thread_data
70 {
71    void (*func)(void*);
72    void *userdata;
73 };
74 
75 struct sthread
76 {
77 #ifdef USE_WIN32_THREADS
78    HANDLE thread;
79    DWORD id;
80 #else
81    pthread_t id;
82 #endif
83 };
84 
85 struct slock
86 {
87 #ifdef USE_WIN32_THREADS
88    CRITICAL_SECTION lock;
89 #else
90    pthread_mutex_t lock;
91 #endif
92 };
93 
94 #ifdef USE_WIN32_THREADS
95 /* The syntax we'll use is mind-bending unless we use a struct. Plus, we might want to store more info later */
96 /* This will be used as a linked list immplementing a queue of waiting threads */
97 struct queue_entry
98 {
99    struct queue_entry *next;
100 };
101 #endif
102 
103 struct scond
104 {
105 #ifdef USE_WIN32_THREADS
106    /* With this implementation of scond, we don't have any way of waking
107     * (or even identifying) specific threads
108     * But we need to wake them in the order indicated by the queue.
109     * This potato token will get get passed around every waiter.
110     * The bearer can test whether he's next, and hold onto the potato if he is.
111     * When he's done he can then put it back into play to progress
112     * the queue further */
113    HANDLE hot_potato;
114 
115    /* The primary signalled event. Hot potatoes are passed until this is set. */
116    HANDLE event;
117 
118    /* the head of the queue; NULL if queue is empty */
119    struct queue_entry *head;
120 
121    /* equivalent to the queue length */
122    int waiters;
123 
124    /* how many waiters in the queue have been conceptually wakened by signals
125     * (even if we haven't managed to actually wake them yet) */
126    int wakens;
127 
128    /* used to control access to this scond, in case the user fails */
129    CRITICAL_SECTION cs;
130 
131 #else
132    pthread_cond_t cond;
133 #endif
134 };
135 
136 #ifdef USE_WIN32_THREADS
thread_wrap(void * data_)137 static DWORD CALLBACK thread_wrap(void *data_)
138 #else
139 static void *thread_wrap(void *data_)
140 #endif
141 {
142    struct thread_data *data = (struct thread_data*)data_;
143    if (!data)
144 	   return 0;
145    data->func(data->userdata);
146    free(data);
147    return 0;
148 }
149 
150 /**
151  * sthread_create:
152  * @start_routine           : thread entry callback function
153  * @userdata                : pointer to userdata that will be made
154  *                            available in thread entry callback function
155  *
156  * Create a new thread.
157  *
158  * Returns: pointer to new thread if successful, otherwise NULL.
159  */
sthread_create(void (* thread_func)(void *),void * userdata)160 sthread_t *sthread_create(void (*thread_func)(void*), void *userdata)
161 {
162 	return sthread_create_with_priority(thread_func, userdata, 0);
163 }
164 
165 /* TODO/FIXME - this needs to be implemented for Switch/3DS */
166 #if !defined(SWITCH) && !defined(USE_WIN32_THREADS) && !defined(_3DS) && !defined(GEKKO) && !defined(__HAIKU__) && !defined(EMSCRIPTEN)
167 #define HAVE_THREAD_ATTR
168 #endif
169 
170 /**
171  * sthread_create_with_priority:
172  * @start_routine           : thread entry callback function
173  * @userdata                : pointer to userdata that will be made
174  *                            available in thread entry callback function
175  * @thread_priority         : thread priority hint value from [1-100]
176  *
177  * Create a new thread. It is possible for the caller to give a hint
178  * for the thread's priority from [1-100]. Any passed in @thread_priority
179  * values that are outside of this range will cause sthread_create() to
180  * create a new thread using the operating system's default thread
181  * priority.
182  *
183  * Returns: pointer to new thread if successful, otherwise NULL.
184  */
sthread_create_with_priority(void (* thread_func)(void *),void * userdata,int thread_priority)185 sthread_t *sthread_create_with_priority(void (*thread_func)(void*), void *userdata, int thread_priority)
186 {
187 #ifdef HAVE_THREAD_ATTR
188    pthread_attr_t thread_attr;
189    bool thread_attr_needed  = false;
190 #endif
191    bool thread_created      = false;
192    struct thread_data *data = NULL;
193    sthread_t *thread        = (sthread_t*)malloc(sizeof(*thread));
194 
195    if (!thread)
196       return NULL;
197 
198    data                     = (struct thread_data*)malloc(sizeof(*data));
199    if (!data)
200       goto error;
201 
202    data->func               = thread_func;
203    data->userdata           = userdata;
204 
205 #ifdef USE_WIN32_THREADS
206    thread->id               = 0;
207    thread->thread           = CreateThread(NULL, 0, thread_wrap,
208          data, 0, &thread->id);
209    thread_created           = !!thread->thread;
210 #else
211    thread->id               = 0;
212 
213 #ifdef HAVE_THREAD_ATTR
214    pthread_attr_init(&thread_attr);
215 
216    if ((thread_priority >= 1) && (thread_priority <= 100))
217    {
218       struct sched_param sp;
219       memset(&sp, 0, sizeof(struct sched_param));
220       sp.sched_priority = thread_priority;
221       pthread_attr_setschedpolicy(&thread_attr, SCHED_RR);
222       pthread_attr_setschedparam(&thread_attr, &sp);
223 
224       thread_attr_needed = true;
225    }
226 #endif
227 
228 #if defined(VITA)
229    pthread_attr_setstacksize(&thread_attr , 0x10000 );
230    thread_attr_needed = true;
231 #endif
232 
233 #ifdef HAVE_THREAD_ATTR
234    if (thread_attr_needed)
235       thread_created = pthread_create(&thread->id, &thread_attr, thread_wrap, data) == 0;
236    else
237 #endif
238       thread_created = pthread_create(&thread->id, NULL, thread_wrap, data) == 0;
239 
240 #ifdef HAVE_THREAD_ATTR
241    pthread_attr_destroy(&thread_attr);
242 #endif
243 #endif
244 
245    if (thread_created)
246       return thread;
247 
248 error:
249    if (data)
250       free(data);
251    free(thread);
252    return NULL;
253 }
254 
255 /**
256  * sthread_detach:
257  * @thread                  : pointer to thread object
258  *
259  * Detach a thread. When a detached thread terminates, its
260  * resources are automatically released back to the system
261  * without the need for another thread to join with the
262  * terminated thread.
263  *
264  * Returns: 0 on success, otherwise it returns a non-zero error number.
265  */
sthread_detach(sthread_t * thread)266 int sthread_detach(sthread_t *thread)
267 {
268 #ifdef USE_WIN32_THREADS
269    CloseHandle(thread->thread);
270    free(thread);
271    return 0;
272 #else
273    int ret = pthread_detach(thread->id);
274    free(thread);
275    return ret;
276 #endif
277 }
278 
279 /**
280  * sthread_join:
281  * @thread                  : pointer to thread object
282  *
283  * Join with a terminated thread. Waits for the thread specified by
284  * @thread to terminate. If that thread has already terminated, then
285  * it will return immediately. The thread specified by @thread must
286  * be joinable.
287  *
288  * Returns: 0 on success, otherwise it returns a non-zero error number.
289  */
sthread_join(sthread_t * thread)290 void sthread_join(sthread_t *thread)
291 {
292    if (!thread)
293       return;
294 #ifdef USE_WIN32_THREADS
295    WaitForSingleObject(thread->thread, INFINITE);
296    CloseHandle(thread->thread);
297 #else
298    pthread_join(thread->id, NULL);
299 #endif
300    free(thread);
301 }
302 
303 /**
304  * sthread_isself:
305  * @thread                  : pointer to thread object
306  *
307  * Returns: true (1) if calling thread is the specified thread
308  */
sthread_isself(sthread_t * thread)309 bool sthread_isself(sthread_t *thread)
310 {
311   /* This thread can't possibly be a null thread */
312   if (!thread)
313      return false;
314 
315 #ifdef USE_WIN32_THREADS
316    return GetCurrentThreadId() == thread->id;
317 #else
318    return pthread_equal(pthread_self(),thread->id);
319 #endif
320 }
321 
322 /**
323  * slock_new:
324  *
325  * Create and initialize a new mutex. Must be manually
326  * freed.
327  *
328  * Returns: pointer to a new mutex if successful, otherwise NULL.
329  **/
slock_new(void)330 slock_t *slock_new(void)
331 {
332    bool mutex_created = false;
333    slock_t      *lock = (slock_t*)calloc(1, sizeof(*lock));
334    if (!lock)
335       return NULL;
336 
337 
338 #ifdef USE_WIN32_THREADS
339    InitializeCriticalSection(&lock->lock);
340    mutex_created             = true;
341 #else
342    mutex_created             = (pthread_mutex_init(&lock->lock, NULL) == 0);
343 #endif
344 
345    if (!mutex_created)
346       goto error;
347 
348    return lock;
349 
350 error:
351    free(lock);
352    return NULL;
353 }
354 
355 /**
356  * slock_free:
357  * @lock                    : pointer to mutex object
358  *
359  * Frees a mutex.
360  **/
slock_free(slock_t * lock)361 void slock_free(slock_t *lock)
362 {
363    if (!lock)
364       return;
365 
366 #ifdef USE_WIN32_THREADS
367    DeleteCriticalSection(&lock->lock);
368 #else
369    pthread_mutex_destroy(&lock->lock);
370 #endif
371    free(lock);
372 }
373 
374 /**
375  * slock_lock:
376  * @lock                    : pointer to mutex object
377  *
378  * Locks a mutex. If a mutex is already locked by
379  * another thread, the calling thread shall block until
380  * the mutex becomes available.
381 **/
slock_lock(slock_t * lock)382 void slock_lock(slock_t *lock)
383 {
384    if (!lock)
385       return;
386 #ifdef USE_WIN32_THREADS
387    EnterCriticalSection(&lock->lock);
388 #else
389    pthread_mutex_lock(&lock->lock);
390 #endif
391 }
392 
393 /**
394  * slock_try_lock:
395  * @lock                    : pointer to mutex object
396  *
397  * Attempts to lock a mutex. If a mutex is already locked by
398  * another thread, return false.  If the lock is acquired, return true.
399 **/
slock_try_lock(slock_t * lock)400 bool slock_try_lock(slock_t *lock)
401 {
402    if (!lock)
403       return false;
404 #ifdef USE_WIN32_THREADS
405    return TryEnterCriticalSection(&lock->lock);
406 #else
407    return pthread_mutex_trylock(&lock->lock)==0;
408 #endif
409 }
410 
411 /**
412  * slock_unlock:
413  * @lock                    : pointer to mutex object
414  *
415  * Unlocks a mutex.
416  **/
slock_unlock(slock_t * lock)417 void slock_unlock(slock_t *lock)
418 {
419    if (!lock)
420       return;
421 #ifdef USE_WIN32_THREADS
422    LeaveCriticalSection(&lock->lock);
423 #else
424    pthread_mutex_unlock(&lock->lock);
425 #endif
426 }
427 
428 /**
429  * scond_new:
430  *
431  * Creates and initializes a condition variable. Must
432  * be manually freed.
433  *
434  * Returns: pointer to new condition variable on success,
435  * otherwise NULL.
436  **/
scond_new(void)437 scond_t *scond_new(void)
438 {
439    scond_t      *cond = (scond_t*)calloc(1, sizeof(*cond));
440 
441    if (!cond)
442       return NULL;
443 
444 #ifdef USE_WIN32_THREADS
445    /* This is very complex because recreating condition variable semantics
446     * with Win32 parts is not easy.
447     *
448     * The main problem is that a condition variable can't be used to
449     * "pre-wake" a thread (it will get wakened only after it's waited).
450     *
451     * Whereas a win32 event can pre-wake a thread (the event will be set
452     * in advance, so a 'waiter' won't even have to wait on it).
453     *
454     * Keep in mind a condition variable can apparently pre-wake a thread,
455     * insofar as spurious wakeups are always possible,
456     * but nobody will be expecting this and it does not need to be simulated.
457     *
458     * Moreover, we won't be doing this, because it counts as a spurious wakeup
459     * -- someone else with a genuine claim must get wakened, in any case.
460     *
461     * Therefore we choose to wake only one of the correct waiting threads.
462     * So at the very least, we need to do something clever. But there's
463     * bigger problems.
464     * We don't even have a straightforward way in win32 to satisfy
465     * pthread_cond_wait's atomicity requirement. The bulk of this
466     * algorithm is solving that.
467     *
468     * Note: We might could simplify this using vista+ condition variables,
469     * but we wanted an XP compatible solution. */
470    cond->event             = CreateEvent(NULL, FALSE, FALSE, NULL);
471    if (!cond->event)
472       goto error;
473    cond->hot_potato        = CreateEvent(NULL, FALSE, FALSE, NULL);
474    if (!cond->hot_potato)
475    {
476       CloseHandle(cond->event);
477       goto error;
478    }
479 
480    InitializeCriticalSection(&cond->cs);
481 #else
482    if (pthread_cond_init(&cond->cond, NULL) != 0)
483       goto error;
484 #endif
485 
486    return cond;
487 
488 error:
489    free(cond);
490    return NULL;
491 }
492 
493 /**
494  * scond_free:
495  * @cond                    : pointer to condition variable object
496  *
497  * Frees a condition variable.
498 **/
scond_free(scond_t * cond)499 void scond_free(scond_t *cond)
500 {
501    if (!cond)
502       return;
503 
504 #ifdef USE_WIN32_THREADS
505    CloseHandle(cond->event);
506    CloseHandle(cond->hot_potato);
507    DeleteCriticalSection(&cond->cs);
508 #else
509    pthread_cond_destroy(&cond->cond);
510 #endif
511    free(cond);
512 }
513 
514 #ifdef USE_WIN32_THREADS
_scond_wait_win32(scond_t * cond,slock_t * lock,DWORD dwMilliseconds)515 static bool _scond_wait_win32(scond_t *cond, slock_t *lock, DWORD dwMilliseconds)
516 {
517    struct queue_entry myentry;
518    struct queue_entry **ptr;
519 
520 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
521    static LARGE_INTEGER performanceCounterFrequency;
522    LARGE_INTEGER tsBegin;
523    static bool first_init  = true;
524 #else
525    static bool beginPeriod = false;
526    DWORD tsBegin;
527 #endif
528 
529    DWORD waitResult;
530    DWORD dwFinalTimeout = dwMilliseconds; /* Careful! in case we begin in the head,
531                                              we don't do the hot potato stuff,
532                                              so this timeout needs presetting. */
533 
534    /* Reminder: `lock` is held before this is called. */
535    /* however, someone else may have called scond_signal without the lock. soo... */
536    EnterCriticalSection(&cond->cs);
537 
538    /* since this library is meant for realtime game software
539     * I have no problem setting this to 1 and forgetting about it. */
540 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
541    if (first_init)
542    {
543       performanceCounterFrequency.QuadPart = 0;
544       first_init = false;
545    }
546 
547    if (performanceCounterFrequency.QuadPart == 0)
548    {
549       QueryPerformanceFrequency(&performanceCounterFrequency);
550    }
551 #else
552    if (!beginPeriod)
553    {
554       beginPeriod = true;
555       timeBeginPeriod(1);
556    }
557 #endif
558 
559    /* Now we can take a good timestamp for use in faking the timeout ourselves. */
560    /* But don't bother unless we need to (to save a little time) */
561    if (dwMilliseconds != INFINITE)
562 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
563       QueryPerformanceCounter(&tsBegin);
564 #else
565       tsBegin = timeGetTime();
566 #endif
567 
568    /* add ourselves to a queue of waiting threads */
569    ptr = &cond->head;
570 
571    /* walk to the end of the linked list */
572    while (*ptr)
573       ptr = &((*ptr)->next);
574 
575    *ptr = &myentry;
576    myentry.next = NULL;
577 
578    cond->waiters++;
579 
580    /* now the conceptual lock release and condition block are supposed to be atomic.
581     * we can't do that in Windows, but we can simulate the effects by using
582     * the queue, by the following analysis:
583     * What happens if they aren't atomic?
584     *
585     * 1. a signaller can rush in and signal, expecting a waiter to get it;
586     * but the waiter wouldn't, because he isn't blocked yet.
587     * Solution: Win32 events make this easy. The event will sit there enabled
588     *
589     * 2. a signaller can rush in and signal, and then turn right around and wait.
590     * Solution: the signaller will get queued behind the waiter, who's
591     * enqueued before he releases the mutex. */
592 
593    /* It's my turn if I'm the head of the queue.
594     * Check to see if it's my turn. */
595    while (cond->head != &myentry)
596    {
597       /* It isn't my turn: */
598       DWORD timeout = INFINITE;
599 
600       /* As long as someone is even going to be able to wake up
601        * when they receive the potato, keep it going round. */
602       if (cond->wakens > 0)
603          SetEvent(cond->hot_potato);
604 
605       /* Assess the remaining timeout time */
606       if (dwMilliseconds != INFINITE)
607       {
608 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
609          LARGE_INTEGER now;
610          LONGLONG elapsed;
611 
612          QueryPerformanceCounter(&now);
613          elapsed  = now.QuadPart - tsBegin.QuadPart;
614          elapsed *= 1000;
615          elapsed /= performanceCounterFrequency.QuadPart;
616 #else
617          DWORD now     = timeGetTime();
618          DWORD elapsed = now - tsBegin;
619 #endif
620 
621          /* Try one last time with a zero timeout (keeps the code simpler) */
622          if (elapsed > dwMilliseconds)
623             elapsed = dwMilliseconds;
624 
625          timeout = dwMilliseconds - elapsed;
626       }
627 
628       /* Let someone else go */
629       LeaveCriticalSection(&lock->lock);
630       LeaveCriticalSection(&cond->cs);
631 
632       /* Wait a while to catch the hot potato..
633        * someone else should get a chance to go */
634       /* After all, it isn't my turn (and it must be someone else's) */
635       Sleep(0);
636       waitResult = WaitForSingleObject(cond->hot_potato, timeout);
637 
638       /* I should come out of here with the main lock taken */
639       EnterCriticalSection(&lock->lock);
640       EnterCriticalSection(&cond->cs);
641 
642       if (waitResult == WAIT_TIMEOUT)
643       {
644          /* Out of time! Now, let's think about this. I do have the potato now--
645           * maybe it's my turn, and I have the event?
646           * If that's the case, I could proceed right now without aborting
647           * due to timeout.
648           *
649           * However.. I DID wait a real long time. The caller was willing
650           * to wait that long.
651           *
652           * I choose to give him one last chance with a zero timeout
653           * in the next step
654           */
655          if (cond->head == &myentry)
656          {
657             dwFinalTimeout = 0;
658             break;
659          }
660          else
661          {
662             /* It's not our turn and we're out of time. Give up.
663              * Remove ourself from the queue and bail. */
664             struct queue_entry *curr = cond->head;
665 
666             while (curr->next != &myentry)
667                curr = curr->next;
668             curr->next = myentry.next;
669             cond->waiters--;
670             LeaveCriticalSection(&cond->cs);
671             return false;
672          }
673       }
674 
675    }
676 
677    /* It's my turn now -- and I hold the potato */
678 
679    /* I still have the main lock, in any case */
680    /* I need to release it so that someone can set the event */
681    LeaveCriticalSection(&lock->lock);
682    LeaveCriticalSection(&cond->cs);
683 
684    /* Wait for someone to actually signal this condition */
685    /* We're the only waiter waiting on the event right now -- everyone else
686     * is waiting on something different */
687    waitResult = WaitForSingleObject(cond->event, dwFinalTimeout);
688 
689    /* Take the main lock so we can do work. Nobody else waits on this lock
690     * for very long, so even though it's GO TIME we won't have to wait long */
691    EnterCriticalSection(&lock->lock);
692    EnterCriticalSection(&cond->cs);
693 
694    /* Remove ourselves from the queue */
695    cond->head = myentry.next;
696    cond->waiters--;
697 
698    if (waitResult == WAIT_TIMEOUT)
699    {
700       /* Oops! ran out of time in the final wait. Just bail. */
701       LeaveCriticalSection(&cond->cs);
702       return false;
703    }
704 
705    /* If any other wakenings are pending, go ahead and set it up  */
706    /* There may actually be no waiters. That's OK. The first waiter will come in,
707     * find it's his turn, and immediately get the signaled event */
708    cond->wakens--;
709    if (cond->wakens > 0)
710    {
711       SetEvent(cond->event);
712 
713       /* Progress the queue: Put the hot potato back into play. It'll be
714        * tossed around until next in line gets it */
715       SetEvent(cond->hot_potato);
716    }
717 
718    LeaveCriticalSection(&cond->cs);
719    return true;
720 }
721 #endif
722 
723 /**
724  * scond_wait:
725  * @cond                    : pointer to condition variable object
726  * @lock                    : pointer to mutex object
727  *
728  * Block on a condition variable (i.e. wait on a condition).
729  **/
scond_wait(scond_t * cond,slock_t * lock)730 void scond_wait(scond_t *cond, slock_t *lock)
731 {
732 #ifdef USE_WIN32_THREADS
733    _scond_wait_win32(cond, lock, INFINITE);
734 #else
735    pthread_cond_wait(&cond->cond, &lock->lock);
736 #endif
737 }
738 
739 /**
740  * scond_broadcast:
741  * @cond                    : pointer to condition variable object
742  *
743  * Broadcast a condition. Unblocks all threads currently blocked
744  * on the specified condition variable @cond.
745  **/
scond_broadcast(scond_t * cond)746 int scond_broadcast(scond_t *cond)
747 {
748 #ifdef USE_WIN32_THREADS
749    /* remember: we currently have mutex */
750    if (cond->waiters == 0)
751       return 0;
752 
753    /* awaken everything which is currently queued up */
754    if (cond->wakens == 0)
755       SetEvent(cond->event);
756    cond->wakens = cond->waiters;
757 
758    /* Since there is now at least one pending waken, the potato must be in play */
759    SetEvent(cond->hot_potato);
760 
761    return 0;
762 #else
763    return pthread_cond_broadcast(&cond->cond);
764 #endif
765 }
766 
767 /**
768  * scond_signal:
769  * @cond                    : pointer to condition variable object
770  *
771  * Signal a condition. Unblocks at least one of the threads currently blocked
772  * on the specified condition variable @cond.
773  **/
scond_signal(scond_t * cond)774 void scond_signal(scond_t *cond)
775 {
776 #ifdef USE_WIN32_THREADS
777 
778    /* Unfortunately, pthread_cond_signal does not require that the
779     * lock be held in advance */
780    /* To avoid stomping on the condvar from other threads, we need
781     * to control access to it with this */
782    EnterCriticalSection(&cond->cs);
783 
784    /* remember: we currently have mutex */
785    if (cond->waiters == 0)
786    {
787       LeaveCriticalSection(&cond->cs);
788       return;
789    }
790 
791    /* wake up the next thing in the queue */
792    if (cond->wakens == 0)
793       SetEvent(cond->event);
794 
795    cond->wakens++;
796 
797    /* The data structure is done being modified.. I think we can leave the CS now.
798     * This would prevent some other thread from receiving the hot potato and then
799     * immediately stalling for the critical section.
800     * But remember, we were trying to replicate a semantic where this entire
801     * scond_signal call was controlled (by the user) by a lock.
802     * So in case there's trouble with this, we can move it after SetEvent() */
803    LeaveCriticalSection(&cond->cs);
804 
805    /* Since there is now at least one pending waken, the potato must be in play */
806    SetEvent(cond->hot_potato);
807 
808 #else
809    pthread_cond_signal(&cond->cond);
810 #endif
811 }
812 
813 /**
814  * scond_wait_timeout:
815  * @cond                    : pointer to condition variable object
816  * @lock                    : pointer to mutex object
817  * @timeout_us              : timeout (in microseconds)
818  *
819  * Try to block on a condition variable (i.e. wait on a condition) until
820  * @timeout_us elapses.
821  *
822  * Returns: false (0) if timeout elapses before condition variable is
823  * signaled or broadcast, otherwise true (1).
824  **/
scond_wait_timeout(scond_t * cond,slock_t * lock,int64_t timeout_us)825 bool scond_wait_timeout(scond_t *cond, slock_t *lock, int64_t timeout_us)
826 {
827 #ifdef USE_WIN32_THREADS
828    /* How to convert a microsecond (us) timeout to millisecond (ms)?
829     *
830     * Someone asking for a 0 timeout clearly wants immediate timeout.
831     * Someone asking for a 1 timeout clearly wants an actual timeout
832     * of the minimum length */
833 
834    /* Someone asking for 1000 or 1001 timeout shouldn't
835     * accidentally get 2ms. */
836    DWORD dwMilliseconds = timeout_us/1000;
837 
838    /* The implementation of a 0 timeout here with pthreads is sketchy.
839     * It isn't clear what happens if pthread_cond_timedwait is called with NOW.
840     * Moreover, it is possible that this thread gets pre-empted after the
841     * clock_gettime but before the pthread_cond_timedwait.
842     * In order to help smoke out problems caused by this strange usage,
843     * let's treat a 0 timeout as always timing out.
844     */
845    if (timeout_us == 0)
846       return false;
847    else if (timeout_us < 1000)
848       dwMilliseconds = 1;
849 
850    return _scond_wait_win32(cond,lock,dwMilliseconds);
851 #else
852    int ret;
853    int64_t seconds, remainder;
854    struct timespec now = {0};
855 
856 #ifdef __MACH__
857    /* OSX doesn't have clock_gettime. */
858    clock_serv_t cclock;
859    mach_timespec_t mts;
860 
861    host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
862    clock_get_time(cclock, &mts);
863    mach_port_deallocate(mach_task_self(), cclock);
864    now.tv_sec = mts.tv_sec;
865    now.tv_nsec = mts.tv_nsec;
866 #elif defined(PS2)
867    int tickms = ps2_clock();
868    now.tv_sec = tickms/1000;
869    now.tv_nsec = tickms * 1000;
870 #elif defined(__mips__) || defined(VITA) || defined(_3DS)
871    struct timeval tm;
872 
873    gettimeofday(&tm, NULL);
874    now.tv_sec = tm.tv_sec;
875    now.tv_nsec = tm.tv_usec * 1000;
876 #elif defined(RETRO_WIN32_USE_PTHREADS)
877    _ftime64_s(&now);
878 #elif !defined(GEKKO)
879    /* timeout on libogc is duration, not end time. */
880    clock_gettime(CLOCK_REALTIME, &now);
881 #endif
882 
883    seconds      = timeout_us / INT64_C(1000000);
884    remainder    = timeout_us % INT64_C(1000000);
885 
886    now.tv_sec  += seconds;
887    now.tv_nsec += remainder * INT64_C(1000);
888 
889    if (now.tv_nsec > 1000000000)
890    {
891       now.tv_nsec -= 1000000000;
892       now.tv_sec += 1;
893    }
894 
895    ret = pthread_cond_timedwait(&cond->cond, &lock->lock, &now);
896    return (ret == 0);
897 #endif
898 }
899 
900 #ifdef HAVE_THREAD_STORAGE
sthread_tls_create(sthread_tls_t * tls)901 bool sthread_tls_create(sthread_tls_t *tls)
902 {
903 #ifdef USE_WIN32_THREADS
904    return (*tls = TlsAlloc()) != TLS_OUT_OF_INDEXES;
905 #else
906    return pthread_key_create((pthread_key_t*)tls, NULL) == 0;
907 #endif
908 }
909 
sthread_tls_delete(sthread_tls_t * tls)910 bool sthread_tls_delete(sthread_tls_t *tls)
911 {
912 #ifdef USE_WIN32_THREADS
913    return TlsFree(*tls) != 0;
914 #else
915    return pthread_key_delete(*tls) == 0;
916 #endif
917 }
918 
sthread_tls_get(sthread_tls_t * tls)919 void *sthread_tls_get(sthread_tls_t *tls)
920 {
921 #ifdef USE_WIN32_THREADS
922    return TlsGetValue(*tls);
923 #else
924    return pthread_getspecific(*tls);
925 #endif
926 }
927 
sthread_tls_set(sthread_tls_t * tls,const void * data)928 bool sthread_tls_set(sthread_tls_t *tls, const void *data)
929 {
930 #ifdef USE_WIN32_THREADS
931    return TlsSetValue(*tls, (void*)data) != 0;
932 #else
933    return pthread_setspecific(*tls, data) == 0;
934 #endif
935 }
936 #endif
937 
sthread_get_thread_id(sthread_t * thread)938 uintptr_t sthread_get_thread_id(sthread_t *thread)
939 {
940    if (!thread)
941       return 0;
942    return (uintptr_t)thread->id;
943 }
944 
sthread_get_current_thread_id(void)945 uintptr_t sthread_get_current_thread_id(void)
946 {
947 #ifdef USE_WIN32_THREADS
948    return (uintptr_t)GetCurrentThreadId();
949 #else
950    return (uintptr_t)pthread_self();
951 #endif
952 }
953