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 struct thread_data
68 {
69    void (*func)(void*);
70    void *userdata;
71 };
72 
73 struct sthread
74 {
75 #ifdef USE_WIN32_THREADS
76    HANDLE thread;
77    DWORD id;
78 #else
79    pthread_t id;
80 #endif
81 };
82 
83 struct slock
84 {
85 #ifdef USE_WIN32_THREADS
86    CRITICAL_SECTION lock;
87 #else
88    pthread_mutex_t lock;
89 #endif
90 };
91 
92 #ifdef USE_WIN32_THREADS
93 /* The syntax we'll use is mind-bending unless we use a struct. Plus, we might want to store more info later */
94 /* This will be used as a linked list immplementing a queue of waiting threads */
95 struct queue_entry
96 {
97    struct queue_entry *next;
98 };
99 #endif
100 
101 struct scond
102 {
103 #ifdef USE_WIN32_THREADS
104    /* With this implementation of scond, we don't have any way of waking
105     * (or even identifying) specific threads
106     * But we need to wake them in the order indicated by the queue.
107     * This potato token will get get passed around every waiter.
108     * The bearer can test whether he's next, and hold onto the potato if he is.
109     * When he's done he can then put it back into play to progress
110     * the queue further */
111    HANDLE hot_potato;
112 
113    /* The primary signalled event. Hot potatoes are passed until this is set. */
114    HANDLE event;
115 
116    /* the head of the queue; NULL if queue is empty */
117    struct queue_entry *head;
118 
119    /* equivalent to the queue length */
120    int waiters;
121 
122    /* how many waiters in the queue have been conceptually wakened by signals
123     * (even if we haven't managed to actually wake them yet) */
124    int wakens;
125 
126    /* used to control access to this scond, in case the user fails */
127    CRITICAL_SECTION cs;
128 
129 #else
130    pthread_cond_t cond;
131 #endif
132 };
133 
134 #ifdef USE_WIN32_THREADS
thread_wrap(void * data_)135 static DWORD CALLBACK thread_wrap(void *data_)
136 #else
137 static void *thread_wrap(void *data_)
138 #endif
139 {
140    struct thread_data *data = (struct thread_data*)data_;
141    if (!data)
142 	   return 0;
143    data->func(data->userdata);
144    free(data);
145    return 0;
146 }
147 
148 /**
149  * sthread_create:
150  * @start_routine           : thread entry callback function
151  * @userdata                : pointer to userdata that will be made
152  *                            available in thread entry callback function
153  *
154  * Create a new thread.
155  *
156  * Returns: pointer to new thread if successful, otherwise NULL.
157  */
sthread_create(void (* thread_func)(void *),void * userdata)158 sthread_t *sthread_create(void (*thread_func)(void*), void *userdata)
159 {
160 	return sthread_create_with_priority(thread_func, userdata, 0);
161 }
162 
163 /* TODO/FIXME - this needs to be implemented for Switch/3DS */
164 #if !defined(SWITCH) && !defined(USE_WIN32_THREADS) && !defined(_3DS) && !defined(GEKKO) && !defined(__HAIKU__) && !defined(EMSCRIPTEN)
165 #define HAVE_THREAD_ATTR
166 #endif
167 
168 /**
169  * sthread_create_with_priority:
170  * @start_routine           : thread entry callback function
171  * @userdata                : pointer to userdata that will be made
172  *                            available in thread entry callback function
173  * @thread_priority         : thread priority hint value from [1-100]
174  *
175  * Create a new thread. It is possible for the caller to give a hint
176  * for the thread's priority from [1-100]. Any passed in @thread_priority
177  * values that are outside of this range will cause sthread_create() to
178  * create a new thread using the operating system's default thread
179  * priority.
180  *
181  * Returns: pointer to new thread if successful, otherwise NULL.
182  */
sthread_create_with_priority(void (* thread_func)(void *),void * userdata,int thread_priority)183 sthread_t *sthread_create_with_priority(void (*thread_func)(void*), void *userdata, int thread_priority)
184 {
185 #ifdef HAVE_THREAD_ATTR
186    pthread_attr_t thread_attr;
187    bool thread_attr_needed  = false;
188 #endif
189    bool thread_created      = false;
190    struct thread_data *data = NULL;
191    sthread_t *thread        = (sthread_t*)malloc(sizeof(*thread));
192 
193    if (!thread)
194       return NULL;
195 
196    data                     = (struct thread_data*)malloc(sizeof(*data));
197    if (!data)
198       goto error;
199 
200    data->func               = thread_func;
201    data->userdata           = userdata;
202 
203 #ifdef USE_WIN32_THREADS
204    thread->id               = 0;
205    thread->thread           = CreateThread(NULL, 0, thread_wrap,
206          data, 0, &thread->id);
207    thread_created           = !!thread->thread;
208 #else
209    thread->id               = 0;
210 
211 #ifdef HAVE_THREAD_ATTR
212    pthread_attr_init(&thread_attr);
213 
214    if ((thread_priority >= 1) && (thread_priority <= 100))
215    {
216       struct sched_param sp;
217       memset(&sp, 0, sizeof(struct sched_param));
218       sp.sched_priority = thread_priority;
219       pthread_attr_setschedpolicy(&thread_attr, SCHED_RR);
220       pthread_attr_setschedparam(&thread_attr, &sp);
221 
222       thread_attr_needed = true;
223    }
224 #endif
225 
226 #if defined(VITA)
227    pthread_attr_setstacksize(&thread_attr , 0x10000 );
228    thread_attr_needed = true;
229 #endif
230 
231 #ifdef HAVE_THREAD_ATTR
232    if (thread_attr_needed)
233       thread_created = pthread_create(&thread->id, &thread_attr, thread_wrap, data) == 0;
234    else
235 #endif
236       thread_created = pthread_create(&thread->id, NULL, thread_wrap, data) == 0;
237 
238 #ifdef HAVE_THREAD_ATTR
239    pthread_attr_destroy(&thread_attr);
240 #endif
241 #endif
242 
243    if (thread_created)
244       return thread;
245 
246 error:
247    if (data)
248       free(data);
249    free(thread);
250    return NULL;
251 }
252 
253 /**
254  * sthread_detach:
255  * @thread                  : pointer to thread object
256  *
257  * Detach a thread. When a detached thread terminates, its
258  * resources are automatically released back to the system
259  * without the need for another thread to join with the
260  * terminated thread.
261  *
262  * Returns: 0 on success, otherwise it returns a non-zero error number.
263  */
sthread_detach(sthread_t * thread)264 int sthread_detach(sthread_t *thread)
265 {
266 #ifdef USE_WIN32_THREADS
267    CloseHandle(thread->thread);
268    free(thread);
269    return 0;
270 #else
271    int ret = pthread_detach(thread->id);
272    free(thread);
273    return ret;
274 #endif
275 }
276 
277 /**
278  * sthread_join:
279  * @thread                  : pointer to thread object
280  *
281  * Join with a terminated thread. Waits for the thread specified by
282  * @thread to terminate. If that thread has already terminated, then
283  * it will return immediately. The thread specified by @thread must
284  * be joinable.
285  *
286  * Returns: 0 on success, otherwise it returns a non-zero error number.
287  */
sthread_join(sthread_t * thread)288 void sthread_join(sthread_t *thread)
289 {
290    if (!thread)
291       return;
292 #ifdef USE_WIN32_THREADS
293    WaitForSingleObject(thread->thread, INFINITE);
294    CloseHandle(thread->thread);
295 #else
296    pthread_join(thread->id, NULL);
297 #endif
298    free(thread);
299 }
300 
301 /**
302  * sthread_isself:
303  * @thread                  : pointer to thread object
304  *
305  * Returns: true (1) if calling thread is the specified thread
306  */
sthread_isself(sthread_t * thread)307 bool sthread_isself(sthread_t *thread)
308 {
309   /* This thread can't possibly be a null thread */
310   if (!thread)
311      return false;
312 
313 #ifdef USE_WIN32_THREADS
314    return GetCurrentThreadId() == thread->id;
315 #else
316    return pthread_equal(pthread_self(),thread->id);
317 #endif
318 }
319 
320 /**
321  * slock_new:
322  *
323  * Create and initialize a new mutex. Must be manually
324  * freed.
325  *
326  * Returns: pointer to a new mutex if successful, otherwise NULL.
327  **/
slock_new(void)328 slock_t *slock_new(void)
329 {
330    bool mutex_created = false;
331    slock_t      *lock = (slock_t*)calloc(1, sizeof(*lock));
332    if (!lock)
333       return NULL;
334 
335 
336 #ifdef USE_WIN32_THREADS
337    InitializeCriticalSection(&lock->lock);
338    mutex_created             = true;
339 #else
340    mutex_created             = (pthread_mutex_init(&lock->lock, NULL) == 0);
341 #endif
342 
343    if (!mutex_created)
344       goto error;
345 
346    return lock;
347 
348 error:
349    free(lock);
350    return NULL;
351 }
352 
353 /**
354  * slock_free:
355  * @lock                    : pointer to mutex object
356  *
357  * Frees a mutex.
358  **/
slock_free(slock_t * lock)359 void slock_free(slock_t *lock)
360 {
361    if (!lock)
362       return;
363 
364 #ifdef USE_WIN32_THREADS
365    DeleteCriticalSection(&lock->lock);
366 #else
367    pthread_mutex_destroy(&lock->lock);
368 #endif
369    free(lock);
370 }
371 
372 /**
373  * slock_lock:
374  * @lock                    : pointer to mutex object
375  *
376  * Locks a mutex. If a mutex is already locked by
377  * another thread, the calling thread shall block until
378  * the mutex becomes available.
379 **/
slock_lock(slock_t * lock)380 void slock_lock(slock_t *lock)
381 {
382    if (!lock)
383       return;
384 #ifdef USE_WIN32_THREADS
385    EnterCriticalSection(&lock->lock);
386 #else
387    pthread_mutex_lock(&lock->lock);
388 #endif
389 }
390 
391 /**
392  * slock_try_lock:
393  * @lock                    : pointer to mutex object
394  *
395  * Attempts to lock a mutex. If a mutex is already locked by
396  * another thread, return false.  If the lock is acquired, return true.
397 **/
slock_try_lock(slock_t * lock)398 bool slock_try_lock(slock_t *lock)
399 {
400    if (!lock)
401       return false;
402 #ifdef USE_WIN32_THREADS
403    return TryEnterCriticalSection(&lock->lock);
404 #else
405    return pthread_mutex_trylock(&lock->lock)==0;
406 #endif
407 }
408 
409 /**
410  * slock_unlock:
411  * @lock                    : pointer to mutex object
412  *
413  * Unlocks a mutex.
414  **/
slock_unlock(slock_t * lock)415 void slock_unlock(slock_t *lock)
416 {
417    if (!lock)
418       return;
419 #ifdef USE_WIN32_THREADS
420    LeaveCriticalSection(&lock->lock);
421 #else
422    pthread_mutex_unlock(&lock->lock);
423 #endif
424 }
425 
426 /**
427  * scond_new:
428  *
429  * Creates and initializes a condition variable. Must
430  * be manually freed.
431  *
432  * Returns: pointer to new condition variable on success,
433  * otherwise NULL.
434  **/
scond_new(void)435 scond_t *scond_new(void)
436 {
437    scond_t      *cond = (scond_t*)calloc(1, sizeof(*cond));
438 
439    if (!cond)
440       return NULL;
441 
442 #ifdef USE_WIN32_THREADS
443    /* This is very complex because recreating condition variable semantics
444     * with Win32 parts is not easy.
445     *
446     * The main problem is that a condition variable can't be used to
447     * "pre-wake" a thread (it will get wakened only after it's waited).
448     *
449     * Whereas a win32 event can pre-wake a thread (the event will be set
450     * in advance, so a 'waiter' won't even have to wait on it).
451     *
452     * Keep in mind a condition variable can apparently pre-wake a thread,
453     * insofar as spurious wakeups are always possible,
454     * but nobody will be expecting this and it does not need to be simulated.
455     *
456     * Moreover, we won't be doing this, because it counts as a spurious wakeup
457     * -- someone else with a genuine claim must get wakened, in any case.
458     *
459     * Therefore we choose to wake only one of the correct waiting threads.
460     * So at the very least, we need to do something clever. But there's
461     * bigger problems.
462     * We don't even have a straightforward way in win32 to satisfy
463     * pthread_cond_wait's atomicity requirement. The bulk of this
464     * algorithm is solving that.
465     *
466     * Note: We might could simplify this using vista+ condition variables,
467     * but we wanted an XP compatible solution. */
468    cond->event             = CreateEvent(NULL, FALSE, FALSE, NULL);
469    if (!cond->event)
470       goto error;
471    cond->hot_potato        = CreateEvent(NULL, FALSE, FALSE, NULL);
472    if (!cond->hot_potato)
473    {
474       CloseHandle(cond->event);
475       goto error;
476    }
477 
478    InitializeCriticalSection(&cond->cs);
479 #else
480    if (pthread_cond_init(&cond->cond, NULL) != 0)
481       goto error;
482 #endif
483 
484    return cond;
485 
486 error:
487    free(cond);
488    return NULL;
489 }
490 
491 /**
492  * scond_free:
493  * @cond                    : pointer to condition variable object
494  *
495  * Frees a condition variable.
496 **/
scond_free(scond_t * cond)497 void scond_free(scond_t *cond)
498 {
499    if (!cond)
500       return;
501 
502 #ifdef USE_WIN32_THREADS
503    CloseHandle(cond->event);
504    CloseHandle(cond->hot_potato);
505    DeleteCriticalSection(&cond->cs);
506 #else
507    pthread_cond_destroy(&cond->cond);
508 #endif
509    free(cond);
510 }
511 
512 #ifdef USE_WIN32_THREADS
_scond_wait_win32(scond_t * cond,slock_t * lock,DWORD dwMilliseconds)513 static bool _scond_wait_win32(scond_t *cond, slock_t *lock, DWORD dwMilliseconds)
514 {
515    struct queue_entry myentry;
516    struct queue_entry **ptr;
517 
518 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
519    static LARGE_INTEGER performanceCounterFrequency;
520    LARGE_INTEGER tsBegin;
521    static bool first_init  = true;
522 #else
523    static bool beginPeriod = false;
524    DWORD tsBegin;
525 #endif
526 
527    DWORD waitResult;
528    DWORD dwFinalTimeout = dwMilliseconds; /* Careful! in case we begin in the head,
529                                              we don't do the hot potato stuff,
530                                              so this timeout needs presetting. */
531 
532    /* Reminder: `lock` is held before this is called. */
533    /* however, someone else may have called scond_signal without the lock. soo... */
534    EnterCriticalSection(&cond->cs);
535 
536    /* since this library is meant for realtime game software
537     * I have no problem setting this to 1 and forgetting about it. */
538 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
539    if (first_init)
540    {
541       performanceCounterFrequency.QuadPart = 0;
542       first_init = false;
543    }
544 
545    if (performanceCounterFrequency.QuadPart == 0)
546    {
547       QueryPerformanceFrequency(&performanceCounterFrequency);
548    }
549 #else
550    if (!beginPeriod)
551    {
552       beginPeriod = true;
553       timeBeginPeriod(1);
554    }
555 #endif
556 
557    /* Now we can take a good timestamp for use in faking the timeout ourselves. */
558    /* But don't bother unless we need to (to save a little time) */
559    if (dwMilliseconds != INFINITE)
560 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
561       QueryPerformanceCounter(&tsBegin);
562 #else
563       tsBegin = timeGetTime();
564 #endif
565 
566    /* add ourselves to a queue of waiting threads */
567    ptr = &cond->head;
568 
569    /* walk to the end of the linked list */
570    while (*ptr)
571       ptr = &((*ptr)->next);
572 
573    *ptr = &myentry;
574    myentry.next = NULL;
575 
576    cond->waiters++;
577 
578    /* now the conceptual lock release and condition block are supposed to be atomic.
579     * we can't do that in Windows, but we can simulate the effects by using
580     * the queue, by the following analysis:
581     * What happens if they aren't atomic?
582     *
583     * 1. a signaller can rush in and signal, expecting a waiter to get it;
584     * but the waiter wouldn't, because he isn't blocked yet.
585     * Solution: Win32 events make this easy. The event will sit there enabled
586     *
587     * 2. a signaller can rush in and signal, and then turn right around and wait.
588     * Solution: the signaller will get queued behind the waiter, who's
589     * enqueued before he releases the mutex. */
590 
591    /* It's my turn if I'm the head of the queue.
592     * Check to see if it's my turn. */
593    while (cond->head != &myentry)
594    {
595       /* It isn't my turn: */
596       DWORD timeout = INFINITE;
597 
598       /* As long as someone is even going to be able to wake up
599        * when they receive the potato, keep it going round. */
600       if (cond->wakens > 0)
601          SetEvent(cond->hot_potato);
602 
603       /* Assess the remaining timeout time */
604       if (dwMilliseconds != INFINITE)
605       {
606 #if _WIN32_WINNT >= 0x0500 || defined(_XBOX)
607          LARGE_INTEGER now;
608          LONGLONG elapsed;
609 
610          QueryPerformanceCounter(&now);
611          elapsed  = now.QuadPart - tsBegin.QuadPart;
612          elapsed *= 1000;
613          elapsed /= performanceCounterFrequency.QuadPart;
614 #else
615          DWORD now     = timeGetTime();
616          DWORD elapsed = now - tsBegin;
617 #endif
618 
619          /* Try one last time with a zero timeout (keeps the code simpler) */
620          if (elapsed > dwMilliseconds)
621             elapsed = dwMilliseconds;
622 
623          timeout = dwMilliseconds - elapsed;
624       }
625 
626       /* Let someone else go */
627       LeaveCriticalSection(&lock->lock);
628       LeaveCriticalSection(&cond->cs);
629 
630       /* Wait a while to catch the hot potato..
631        * someone else should get a chance to go */
632       /* After all, it isn't my turn (and it must be someone else's) */
633       Sleep(0);
634       waitResult = WaitForSingleObject(cond->hot_potato, timeout);
635 
636       /* I should come out of here with the main lock taken */
637       EnterCriticalSection(&lock->lock);
638       EnterCriticalSection(&cond->cs);
639 
640       if (waitResult == WAIT_TIMEOUT)
641       {
642          /* Out of time! Now, let's think about this. I do have the potato now--
643           * maybe it's my turn, and I have the event?
644           * If that's the case, I could proceed right now without aborting
645           * due to timeout.
646           *
647           * However.. I DID wait a real long time. The caller was willing
648           * to wait that long.
649           *
650           * I choose to give him one last chance with a zero timeout
651           * in the next step
652           */
653          if (cond->head == &myentry)
654          {
655             dwFinalTimeout = 0;
656             break;
657          }
658          else
659          {
660             /* It's not our turn and we're out of time. Give up.
661              * Remove ourself from the queue and bail. */
662             struct queue_entry *curr = cond->head;
663 
664             while (curr->next != &myentry)
665                curr = curr->next;
666             curr->next = myentry.next;
667             cond->waiters--;
668             LeaveCriticalSection(&cond->cs);
669             return false;
670          }
671       }
672 
673    }
674 
675    /* It's my turn now -- and I hold the potato */
676 
677    /* I still have the main lock, in any case */
678    /* I need to release it so that someone can set the event */
679    LeaveCriticalSection(&lock->lock);
680    LeaveCriticalSection(&cond->cs);
681 
682    /* Wait for someone to actually signal this condition */
683    /* We're the only waiter waiting on the event right now -- everyone else
684     * is waiting on something different */
685    waitResult = WaitForSingleObject(cond->event, dwFinalTimeout);
686 
687    /* Take the main lock so we can do work. Nobody else waits on this lock
688     * for very long, so even though it's GO TIME we won't have to wait long */
689    EnterCriticalSection(&lock->lock);
690    EnterCriticalSection(&cond->cs);
691 
692    /* Remove ourselves from the queue */
693    cond->head = myentry.next;
694    cond->waiters--;
695 
696    if (waitResult == WAIT_TIMEOUT)
697    {
698       /* Oops! ran out of time in the final wait. Just bail. */
699       LeaveCriticalSection(&cond->cs);
700       return false;
701    }
702 
703    /* If any other wakenings are pending, go ahead and set it up  */
704    /* There may actually be no waiters. That's OK. The first waiter will come in,
705     * find it's his turn, and immediately get the signaled event */
706    cond->wakens--;
707    if (cond->wakens > 0)
708    {
709       SetEvent(cond->event);
710 
711       /* Progress the queue: Put the hot potato back into play. It'll be
712        * tossed around until next in line gets it */
713       SetEvent(cond->hot_potato);
714    }
715 
716    LeaveCriticalSection(&cond->cs);
717    return true;
718 }
719 #endif
720 
721 /**
722  * scond_wait:
723  * @cond                    : pointer to condition variable object
724  * @lock                    : pointer to mutex object
725  *
726  * Block on a condition variable (i.e. wait on a condition).
727  **/
scond_wait(scond_t * cond,slock_t * lock)728 void scond_wait(scond_t *cond, slock_t *lock)
729 {
730 #ifdef USE_WIN32_THREADS
731    _scond_wait_win32(cond, lock, INFINITE);
732 #else
733    pthread_cond_wait(&cond->cond, &lock->lock);
734 #endif
735 }
736 
737 /**
738  * scond_broadcast:
739  * @cond                    : pointer to condition variable object
740  *
741  * Broadcast a condition. Unblocks all threads currently blocked
742  * on the specified condition variable @cond.
743  **/
scond_broadcast(scond_t * cond)744 int scond_broadcast(scond_t *cond)
745 {
746 #ifdef USE_WIN32_THREADS
747    /* remember: we currently have mutex */
748    if (cond->waiters == 0)
749       return 0;
750 
751    /* awaken everything which is currently queued up */
752    if (cond->wakens == 0)
753       SetEvent(cond->event);
754    cond->wakens = cond->waiters;
755 
756    /* Since there is now at least one pending waken, the potato must be in play */
757    SetEvent(cond->hot_potato);
758 
759    return 0;
760 #else
761    return pthread_cond_broadcast(&cond->cond);
762 #endif
763 }
764 
765 /**
766  * scond_signal:
767  * @cond                    : pointer to condition variable object
768  *
769  * Signal a condition. Unblocks at least one of the threads currently blocked
770  * on the specified condition variable @cond.
771  **/
scond_signal(scond_t * cond)772 void scond_signal(scond_t *cond)
773 {
774 #ifdef USE_WIN32_THREADS
775 
776    /* Unfortunately, pthread_cond_signal does not require that the
777     * lock be held in advance */
778    /* To avoid stomping on the condvar from other threads, we need
779     * to control access to it with this */
780    EnterCriticalSection(&cond->cs);
781 
782    /* remember: we currently have mutex */
783    if (cond->waiters == 0)
784    {
785       LeaveCriticalSection(&cond->cs);
786       return;
787    }
788 
789    /* wake up the next thing in the queue */
790    if (cond->wakens == 0)
791       SetEvent(cond->event);
792 
793    cond->wakens++;
794 
795    /* The data structure is done being modified.. I think we can leave the CS now.
796     * This would prevent some other thread from receiving the hot potato and then
797     * immediately stalling for the critical section.
798     * But remember, we were trying to replicate a semantic where this entire
799     * scond_signal call was controlled (by the user) by a lock.
800     * So in case there's trouble with this, we can move it after SetEvent() */
801    LeaveCriticalSection(&cond->cs);
802 
803    /* Since there is now at least one pending waken, the potato must be in play */
804    SetEvent(cond->hot_potato);
805 
806 #else
807    pthread_cond_signal(&cond->cond);
808 #endif
809 }
810 
811 /**
812  * scond_wait_timeout:
813  * @cond                    : pointer to condition variable object
814  * @lock                    : pointer to mutex object
815  * @timeout_us              : timeout (in microseconds)
816  *
817  * Try to block on a condition variable (i.e. wait on a condition) until
818  * @timeout_us elapses.
819  *
820  * Returns: false (0) if timeout elapses before condition variable is
821  * signaled or broadcast, otherwise true (1).
822  **/
scond_wait_timeout(scond_t * cond,slock_t * lock,int64_t timeout_us)823 bool scond_wait_timeout(scond_t *cond, slock_t *lock, int64_t timeout_us)
824 {
825 #ifdef USE_WIN32_THREADS
826    /* How to convert a microsecond (us) timeout to millisecond (ms)?
827     *
828     * Someone asking for a 0 timeout clearly wants immediate timeout.
829     * Someone asking for a 1 timeout clearly wants an actual timeout
830     * of the minimum length */
831 
832    /* Someone asking for 1000 or 1001 timeout shouldn't
833     * accidentally get 2ms. */
834    DWORD dwMilliseconds = timeout_us/1000;
835 
836    /* The implementation of a 0 timeout here with pthreads is sketchy.
837     * It isn't clear what happens if pthread_cond_timedwait is called with NOW.
838     * Moreover, it is possible that this thread gets pre-empted after the
839     * clock_gettime but before the pthread_cond_timedwait.
840     * In order to help smoke out problems caused by this strange usage,
841     * let's treat a 0 timeout as always timing out.
842     */
843    if (timeout_us == 0)
844       return false;
845    else if (timeout_us < 1000)
846       dwMilliseconds = 1;
847 
848    return _scond_wait_win32(cond,lock,dwMilliseconds);
849 #else
850    int ret;
851    int64_t seconds, remainder;
852    struct timespec now = {0};
853 
854 #ifdef __MACH__
855    /* OSX doesn't have clock_gettime. */
856    clock_serv_t cclock;
857    mach_timespec_t mts;
858 
859    host_get_clock_service(mach_host_self(), CALENDAR_CLOCK, &cclock);
860    clock_get_time(cclock, &mts);
861    mach_port_deallocate(mach_task_self(), cclock);
862    now.tv_sec = mts.tv_sec;
863    now.tv_nsec = mts.tv_nsec;
864 #elif !defined(__PSL1GHT__) && defined(__PS3__)
865    sys_time_sec_t s;
866    sys_time_nsec_t n;
867 
868    sys_time_get_current_time(&s, &n);
869    now.tv_sec  = s;
870    now.tv_nsec = n;
871 #elif defined(PS2)
872    int tickms = ps2_clock();
873    now.tv_sec = tickms/1000;
874    now.tv_nsec = tickms * 1000;
875 #elif !defined(DINGUX_BETA) && (defined(__mips__) || defined(VITA) || defined(_3DS))
876    struct timeval tm;
877 
878    gettimeofday(&tm, NULL);
879    now.tv_sec = tm.tv_sec;
880    now.tv_nsec = tm.tv_usec * 1000;
881 #elif defined(RETRO_WIN32_USE_PTHREADS)
882    _ftime64_s(&now);
883 #elif !defined(GEKKO)
884    /* timeout on libogc is duration, not end time. */
885    clock_gettime(CLOCK_REALTIME, &now);
886 #endif
887 
888    seconds      = timeout_us / INT64_C(1000000);
889    remainder    = timeout_us % INT64_C(1000000);
890 
891    now.tv_sec  += seconds;
892    now.tv_nsec += remainder * INT64_C(1000);
893 
894    if (now.tv_nsec > 1000000000)
895    {
896       now.tv_nsec -= 1000000000;
897       now.tv_sec += 1;
898    }
899 
900    ret = pthread_cond_timedwait(&cond->cond, &lock->lock, &now);
901    return (ret == 0);
902 #endif
903 }
904 
905 #ifdef HAVE_THREAD_STORAGE
sthread_tls_create(sthread_tls_t * tls)906 bool sthread_tls_create(sthread_tls_t *tls)
907 {
908 #ifdef USE_WIN32_THREADS
909    return (*tls = TlsAlloc()) != TLS_OUT_OF_INDEXES;
910 #else
911    return pthread_key_create((pthread_key_t*)tls, NULL) == 0;
912 #endif
913 }
914 
sthread_tls_delete(sthread_tls_t * tls)915 bool sthread_tls_delete(sthread_tls_t *tls)
916 {
917 #ifdef USE_WIN32_THREADS
918    return TlsFree(*tls) != 0;
919 #else
920    return pthread_key_delete(*tls) == 0;
921 #endif
922 }
923 
sthread_tls_get(sthread_tls_t * tls)924 void *sthread_tls_get(sthread_tls_t *tls)
925 {
926 #ifdef USE_WIN32_THREADS
927    return TlsGetValue(*tls);
928 #else
929    return pthread_getspecific(*tls);
930 #endif
931 }
932 
sthread_tls_set(sthread_tls_t * tls,const void * data)933 bool sthread_tls_set(sthread_tls_t *tls, const void *data)
934 {
935 #ifdef USE_WIN32_THREADS
936    return TlsSetValue(*tls, (void*)data) != 0;
937 #else
938    return pthread_setspecific(*tls, data) == 0;
939 #endif
940 }
941 #endif
942 
sthread_get_thread_id(sthread_t * thread)943 uintptr_t sthread_get_thread_id(sthread_t *thread)
944 {
945    if (!thread)
946       return 0;
947    return (uintptr_t)thread->id;
948 }
949 
sthread_get_current_thread_id(void)950 uintptr_t sthread_get_current_thread_id(void)
951 {
952 #ifdef USE_WIN32_THREADS
953    return (uintptr_t)GetCurrentThreadId();
954 #else
955    return (uintptr_t)pthread_self();
956 #endif
957 }
958