Make and use a semaphore class

Alc/alc.cpp

@@ -2528,7 +2528,6 @@ static ALvoid InitContext(ALCcontext *Context)
     Context->DopplerVelocity = 1.0f;
     Context->SpeedOfSound = SPEEDOFSOUNDMETRESPERSEC;
     Context->MetersPerUnit = AL_DEFAULT_METERS_PER_UNIT;
-    alsem_init(&Context->EventSem, 0);
 
     Context->ExtensionList = alExtList;
 
@@ -2642,8 +2641,6 @@ ALCcontext_struct::~ALCcontext_struct()
     }
     TRACE("Freed " SZFMT " listener property object%s\n", count, (count==1)?"":"s");
 
-    alsem_destroy(&EventSem);
-
     ll_ringbuffer_free(AsyncEvents);
     AsyncEvents = nullptr;
 

Alc/alcontext.h

@@ -111,7 +111,7 @@ struct ALCcontext_struct {
     std::atomic<ALeffectslotArray*> ActiveAuxSlots{nullptr};
 
     std::thread EventThread;
-    alsem_t EventSem;
+    al::semaphore EventSem;
     ll_ringbuffer *AsyncEvents{nullptr};
     std::atomic<ALbitfieldSOFT> EnabledEvts{0u};
     std::mutex EventCbLock;

Alc/alu.cpp

@@ -313,7 +313,7 @@ void SendSourceStoppedEvent(ALCcontext *context, ALuint id)
     strcpy(evt.u.user.msg+strpos, " state changed to AL_STOPPED");
 
     if(ll_ringbuffer_write(context->AsyncEvents, &evt, 1) == 1)
-        alsem_post(&context->EventSem);
+        context->EventSem.post();
 }
 
 
@@ -441,7 +441,7 @@ bool CalcEffectSlotParams(ALeffectslot *slot, ALCcontext *context, bool force)
             props->State = NULL;
 
             if(LIKELY(ll_ringbuffer_write(context->AsyncEvents, &evt, 1) != 0))
-                alsem_post(&context->EventSem);
+                context->EventSem.post();
             else
             {
                 /* If writing the event failed, the queue was probably full.
@@ -1857,7 +1857,7 @@ void aluHandleDisconnect(ALCdevice *device, const char *msg, ...)
         ALbitfieldSOFT enabledevt = ctx->EnabledEvts.load(std::memory_order_acquire);
         if((enabledevt&EventType_Disconnected) &&
            ll_ringbuffer_write(ctx->AsyncEvents, &evt, 1) == 1)
-            alsem_post(&ctx->EventSem);
+            ctx->EventSem.post();
 
         std::for_each(ctx->Voices, ctx->Voices+ctx->VoiceCount.load(std::memory_order_acquire),
             [ctx](ALvoice *voice) -> void

Alc/mixvoice.cpp

@@ -204,7 +204,7 @@ static void SendAsyncEvent(ALCcontext *context, ALuint enumtype, ALenum type,
     evt.u.user.param = param;
     strcpy(evt.u.user.msg, msg);
     if(ll_ringbuffer_write(context->AsyncEvents, &evt, 1) == 1)
-        alsem_post(&context->EventSem);
+        context->EventSem.post();
 }
 
 

OpenAL32/alSource.cpp

@@ -705,7 +705,7 @@ void SendStateChangeEvent(ALCcontext *context, ALuint id, ALenum state)
      * it through the async queue to ensure proper ordering.
      */
     if(ll_ringbuffer_write(context->AsyncEvents, &evt, 1) == 1)
-        alsem_post(&context->EventSem);
+        context->EventSem.post();
 }
 
 

OpenAL32/event.cpp

@@ -23,7 +23,7 @@ static int EventThread(ALCcontext *context)
         AsyncEvent evt;
         if(ll_ringbuffer_read(context->AsyncEvents, &evt, 1) == 0)
         {
-            alsem_wait(&context->EventSem);
+            context->EventSem.wait();
             continue;
         }
 
@@ -66,7 +66,7 @@ void StopEventThrd(ALCcontext *ctx)
     static constexpr AsyncEvent kill_evt = ASYNC_EVENT(EventType_KillThread);
     while(ll_ringbuffer_write(ctx->AsyncEvents, &kill_evt, 1) == 0)
         std::this_thread::yield();
-    alsem_post(&ctx->EventSem);
+    ctx->EventSem.post();
     if(ctx->EventThread.joinable())
         ctx->EventThread.join();
 }

common/threads.cpp

@@ -22,25 +22,7 @@
 
 #include "threads.h"
 
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-
-
-#ifndef UNUSED
-#if defined(__cplusplus)
-#define UNUSED(x)
-#elif defined(__GNUC__)
-#define UNUSED(x) UNUSED_##x __attribute__((unused))
-#elif defined(__LCLINT__)
-#define UNUSED(x) /*@unused@*/ x
-#else
-#define UNUSED(x) x
-#endif
-#endif
-
-
-#define THREAD_STACK_SIZE (2*1024*1024) /* 2MB */
+#include <system_error>
 
 #ifdef _WIN32
 
@@ -116,6 +98,7 @@ int alsem_trywait(alsem_t *sem)
 
 #include <sys/time.h>
 #include <unistd.h>
+#include <errno.h>
 #include <pthread.h>
 #ifdef HAVE_PTHREAD_NP_H
 #include <pthread_np.h>
@@ -210,3 +193,32 @@ int alsem_trywait(alsem_t *sem)
 #endif /* __APPLE__ */
 
 #endif
+
+
+namespace al {
+
+semaphore::semaphore(unsigned int initial)
+{
+    if(alsem_init(&mSem, initial) != althrd_success)
+        throw std::system_error(std::make_error_code(std::errc::resource_unavailable_try_again));
+}
+
+semaphore::~semaphore()
+{ alsem_destroy(&mSem); }
+
+void semaphore::post()
+{
+    if(alsem_post(&mSem) != althrd_success)
+        throw std::system_error(std::make_error_code(std::errc::value_too_large));
+}
+
+void semaphore::wait() noexcept
+{
+    while(alsem_wait(&mSem) == -2) {
+    }
+}
+
+int semaphore::trywait() noexcept
+{ return alsem_wait(&mSem) == althrd_success; }
+
+} // namespace al

common/threads.h

@@ -63,6 +63,26 @@ int alsem_trywait(alsem_t *sem);
 
 #ifdef __cplusplus
 } // extern "C"
+
+namespace al {
+
+class semaphore {
+    alsem_t mSem;
+
+public:
+    semaphore(unsigned int initial=0);
+    semaphore(const semaphore&) = delete;
+    ~semaphore();
+
+    semaphore& operator=(const semaphore&) = delete;
+
+    void post();
+    void wait() noexcept;
+    int trywait() noexcept;
+};
+
+} // namespace al
+
 #endif
 
 #endif /* AL_THREADS_H */