add compatibility std::condition_variable semaphore when posix semaph…

…ores not available
AcademySoftwareFoundation · Aug 8, 2018 · b6dc2a6 · b6dc2a6
1 parent 01680dc
commit b6dc2a6
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Showing 2 changed files with 97 additions and 19 deletions.
diff --git a/IlmBase/IlmThread/IlmThreadSemaphore.h b/IlmBase/IlmThread/IlmThreadSemaphore.h
@@ -47,15 +47,22 @@
 #include "IlmThreadNamespace.h"
 
 #if defined _WIN32 || defined _WIN64
-    #ifdef NOMINMAX
-        #undef NOMINMAX
-    #endif
-    #define NOMINMAX
-    #include <windows.h>
-#elif HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
-    #include <pthread.h>
-#elif HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
-    #include <semaphore.h>
+#   ifdef NOMINMAX
+#      undef NOMINMAX
+#   endif
+#   define NOMINMAX
+#   include <windows.h>
+#elif HAVE_POSIX_SEMAPHORES
+#   include <semaphore.h>
+#else
+#   ifdef ILMBASE_FORCE_CXX03
+#      if HAVE_PTHREAD
+#         include <pthread.h>
+#      endif
+#   else
+#      include <mutex>
+#      include <condition_variable>
+#   endif
 #endif
 
 ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER
@@ -75,12 +82,15 @@ class ILMTHREAD_EXPORT Semaphore
 
   private:
 
-    #if defined _WIN32 || defined _WIN64
+#if defined _WIN32 || defined _WIN64
 
 	mutable HANDLE _semaphore;
 
-    #elif HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
+#elif defined(HAVE_POSIX_SEMAPHORES)
+
+	mutable sem_t _semaphore;
 
+#else
 	//
 	// If the platform has Posix threads but no semapohores,
 	// then we implement them ourselves using condition variables
@@ -90,17 +100,22 @@ class ILMTHREAD_EXPORT Semaphore
 	{
 	    unsigned int count;
 	    unsigned long numWaiting;
+#   if ILMBASE_FORCE_CXX03
+#      if HAVE_PTHREAD
 	    pthread_mutex_t mutex;
 	    pthread_cond_t nonZero;
+#      else
+#         error unhandled legacy setup
+#      endif
+#   else
+        std::mutex mutex;
+        std::condition_variable nonZero;
+#   endif
 	};
 
 	mutable sema_t _semaphore;
-
-    #elif HAVE_PTHREAD && HAVE_POSIX_SEMAPHORES
-
-	mutable sem_t _semaphore;
-
-    #endif
+
+#endif
 
     void operator = (const Semaphore& s);	// not implemented
     Semaphore (const Semaphore& s);		// not implemented

diff --git a/IlmBase/IlmThread/IlmThreadSemaphorePosixCompat.cpp b/IlmBase/IlmThread/IlmThreadSemaphorePosixCompat.cpp
@@ -42,15 +42,15 @@
 
 #include "IlmBaseConfig.h"
 
-#if HAVE_PTHREAD && !HAVE_POSIX_SEMAPHORES
+#if (!HAVE_POSIX_SEMAPHORES) && !defined (_WIN32) && ! defined (_WIN64)
 
 #include "IlmThreadSemaphore.h"
 #include "Iex.h"
 #include <assert.h>
 
 ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_ENTER
 
-
+#if ILMBASE_FORCE_CXX03 && HAVE_PTHREAD
 Semaphore::Semaphore (unsigned int value)
 {
     if (int error = ::pthread_mutex_init (&_semaphore.mutex, 0))
@@ -157,8 +157,71 @@ Semaphore::value () const
     ::pthread_mutex_unlock (&_semaphore.mutex);
     return value;
 }
+#else
+Semaphore::Semaphore (unsigned int value)
+{
+    _semaphore.count = value;
+    _semaphore.numWaiting = 0;
+}
+
+
+Semaphore::~Semaphore ()
+{
+}
 
 
+void
+Semaphore::wait ()
+{
+    std::unique_lock<std::mutex> lk(_semaphore.mutex);
+
+    _semaphore.numWaiting++;
+
+    while (_semaphore.count == 0)
+        _semaphore.nonZero.wait (lk);
+
+    _semaphore.numWaiting--;
+    _semaphore.count--;
+}
+
+
+bool
+Semaphore::tryWait ()
+{
+    std::lock_guard<std::mutex> lk(_semaphore.mutex);
+
+    if (_semaphore.count == 0)
+        return false;
+
+    _semaphore.count--;
+    return true;
+}
+
+
+void
+Semaphore::post ()
+{
+    std::lock_guard<std::mutex> lk(_semaphore.mutex);
+
+    _semaphore.count++;
+    if (_semaphore.numWaiting > 0)
+    {
+        if (_semaphore.count > 1)
+            _semaphore.nonZero.notify_all();
+        else
+            _semaphore.nonZero.notify_one();
+    }
+}
+
+
+int
+Semaphore::value () const
+{
+    std::lock_guard<std::mutex> lk(_semaphore.mutex);
+    return _semaphore.count;
+}
+#endif
+
 ILMTHREAD_INTERNAL_NAMESPACE_SOURCE_EXIT
 
 #endif