SDL & Win32 platform threads cleanup.

Engine/source/platformSDL/threads/semaphore.cpp

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+//-----------------------------------------------------------------------------
+// Copyright (c) 2012 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#include "platform/platformAssert.h"
+#include "platform/threads/semaphore.h"
+#include <SDL.h>
+#include <SDL_thread.h>
+
+struct PlatformSemaphore
+{
+   SDL_sem *semaphore;
+
+   PlatformSemaphore(S32 initialCount)
+   {
+       semaphore = SDL_CreateSemaphore(initialCount);
+       AssertFatal(semaphore, "PlatformSemaphore constructor - Failed to create SDL Semaphore.");
+   }
+
+   ~PlatformSemaphore()
+   {
+       SDL_DestroySemaphore(semaphore);
+   }
+};
+
+Semaphore::Semaphore(S32 initialCount)
+{
+  mData = new PlatformSemaphore(initialCount);
+}
+
+Semaphore::~Semaphore()
+{
+  AssertFatal(mData, "Semaphore destructor - Invalid semaphore.");
+  delete mData;
+}
+
+bool Semaphore::acquire(bool block, S32 timeoutMS)
+{
+   AssertFatal(mData && mData->semaphore, "Semaphore::acquire - Invalid semaphore.");
+   if (block)
+   {
+      // Semaphore acquiring is different from the MacOS/Win realization because SDL_SemWaitTimeout() with "infinite" timeout can be too heavy on some platforms.
+      // (see "man SDL_SemWaitTimeout(3)" for more info)
+      // "man" states to avoid the use of SDL_SemWaitTimeout at all, but at current stage this looks like a valid and working solution, so keeping it this way.
+      // [bank / Feb-2010]
+      if (timeoutMS == -1)
+      {
+         if (SDL_SemWait(mData->semaphore) < 0)
+            AssertFatal(false, "Semaphore::acquie - Wait failed.");
+      }
+      else
+      {
+         if (SDL_SemWaitTimeout(mData->semaphore, timeoutMS) < 0)
+            AssertFatal(false, "Semaphore::acquie - Wait with timeout failed.");
+      }
+      return (true);
+   }
+   else
+   {
+      int res = SDL_SemTryWait(mData->semaphore);
+      return (res == 0);
+   }
+}
+
+void Semaphore::release()
+{
+   AssertFatal(mData, "Semaphore::releaseSemaphore - Invalid semaphore.");
+   SDL_SemPost(mData->semaphore);
+}