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rwlock: Make generic implmentations work on single-threaded platforms. 

Fixes #8101.
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Ryan C. Gordon 2023-08-11 15:02:52 -04:00
parent 80850af7ce
commit b75c751dfc
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GPG Key ID: FA148B892AB48044
1 changed files with 21 additions and 1 deletions
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22
src/thread/generic/SDL_sysrwlock.c
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@ -43,22 +43,27 @@
struct SDL_RWLock
{
#ifdef SDL_THREADS_DISABLED
int unused;
#else
SDL_Mutex *lock;
SDL_Condition *condition;
SDL_threadID writer_thread;
SDL_AtomicInt reader_count;
SDL_AtomicInt writer_count;
#endif
};
SDL_RWLock *SDL_CreateRWLock_generic(void)
{
SDL_RWLock *rwlock = (SDL_RWLock *) SDL_malloc(sizeof (*rwlock));
SDL_RWLock *rwlock = (SDL_RWLock *) SDL_calloc(1, sizeof (*rwlock));
if (!rwlock) {
SDL_OutOfMemory();
return NULL;
}
#ifndef SDL_THREADS_DISABLED
rwlock->lock = SDL_CreateMutex();
if (!rwlock->lock) {
SDL_free(rwlock);
@ -74,6 +79,7 @@ SDL_RWLock *SDL_CreateRWLock_generic(void)
SDL_AtomicSet(&rwlock->reader_count, 0);
SDL_AtomicSet(&rwlock->writer_count, 0);
#endif
return rwlock;
}
@ -81,14 +87,17 @@ SDL_RWLock *SDL_CreateRWLock_generic(void)
void SDL_DestroyRWLock_generic(SDL_RWLock *rwlock)
{
if (rwlock) {
#ifndef SDL_THREADS_DISABLED
SDL_DestroyMutex(rwlock->lock);
SDL_DestroyCondition(rwlock->condition);
#endif
SDL_free(rwlock);
}
}
int SDL_LockRWLockForReading_generic(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS /* clang doesn't know about NULL mutexes */
{
#ifndef SDL_THREADS_DISABLED
if (!rwlock) {
return SDL_InvalidParamError("rwlock");
} else if (SDL_LockMutex(rwlock->lock) == -1) {
@ -99,11 +108,14 @@ int SDL_LockRWLockForReading_generic(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_AN
SDL_AtomicAdd(&rwlock->reader_count, 1);
SDL_UnlockMutex(rwlock->lock); /* other readers can attempt to share the lock. */
#endif
return 0;
}
int SDL_LockRWLockForWriting_generic(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS /* clang doesn't know about NULL mutexes */
{
#ifndef SDL_THREADS_DISABLED
if (!rwlock) {
return SDL_InvalidParamError("rwlock");
} else if (SDL_LockMutex(rwlock->lock) == -1) {
@ -116,12 +128,14 @@ int SDL_LockRWLockForWriting_generic(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_AN
/* we hold the lock! */
SDL_AtomicAdd(&rwlock->writer_count, 1); /* we let these be recursive, but the API doesn't require this. It _does_ trust you unlock correctly! */
#endif
return 0;
}
int SDL_TryLockRWLockForReading_generic(SDL_RWLock *rwlock)
{
#ifndef SDL_THREADS_DISABLED
int rc;
if (!rwlock) {
@ -138,11 +152,14 @@ int SDL_TryLockRWLockForReading_generic(SDL_RWLock *rwlock)
SDL_AtomicAdd(&rwlock->reader_count, 1);
SDL_UnlockMutex(rwlock->lock); /* other readers can attempt to share the lock. */
#endif
return 0;
}
int SDL_TryLockRWLockForWriting_generic(SDL_RWLock *rwlock)
{
#ifndef SDL_THREADS_DISABLED
int rc;
if (!rwlock) {
@ -158,12 +175,14 @@ int SDL_TryLockRWLockForWriting_generic(SDL_RWLock *rwlock)
/* we hold the lock! */
SDL_AtomicAdd(&rwlock->writer_count, 1); /* we let these be recursive, but the API doesn't require this. It _does_ trust you unlock correctly! */
#endif
return 0;
}
int SDL_UnlockRWLock_generic(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS /* clang doesn't know about NULL mutexes */
{
#ifndef SDL_THREADS_DISABLED
if (!rwlock) {
return SDL_InvalidParamError("rwlock");
}
@ -179,6 +198,7 @@ int SDL_UnlockRWLock_generic(SDL_RWLock *rwlock) SDL_NO_THREAD_SAFETY_ANALYSIS /
}
SDL_UnlockMutex(rwlock->lock);
#endif
return 0;
}