Engine directory for ticket #1

Engine/source/platform/threads/mutex.h

@@ -0,0 +1,129 @@
+//-----------------------------------------------------------------------------
+// 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/types.h"
+#include "platform/platformAssert.h"
+
+#ifndef _PLATFORM_THREADS_MUTEX_H_
+#define _PLATFORM_THREADS_MUTEX_H_
+
+// Forward ref used by platform code
+struct PlatformMutexData;
+
+class Mutex
+{
+protected:
+   PlatformMutexData *mData;
+
+public:
+   Mutex();
+   virtual ~Mutex();
+
+   virtual bool lock(bool block = true);
+   virtual void unlock();
+
+   // Old API so that we don't have to change a load of code
+   static void *createMutex()
+   {
+      Mutex *mutex = new Mutex;
+      return (void *)mutex;
+   }
+
+   static void destroyMutex(void *mutex)
+   {
+      Mutex *realMutex = reinterpret_cast<Mutex *>(mutex);
+      delete realMutex;
+   }
+
+   static bool lockMutex(void *mutex, bool block = true)
+   {
+      Mutex *realMutex = reinterpret_cast<Mutex *>(mutex);
+      return realMutex->lock(block);
+   }
+
+   static void unlockMutex(void *mutex)
+   {
+      Mutex *realMutex = reinterpret_cast<Mutex *>(mutex);
+      realMutex->unlock();
+   }
+};
+
+/// Helper for simplifying mutex locking code.
+///
+/// This class will automatically unlock a mutex that you've
+/// locked through it, saving you from managing a lot of complex
+/// exit cases. For instance:
+///
+/// @code
+/// MutexHandle handle;
+/// handle.lock(myMutex);
+///
+/// if(error1)
+///   return; // Auto-unlocked by handle if we leave here - normally would
+///           // leave the mutex locked, causing much pain later.
+///
+/// handle.unlock();
+/// @endcode
+class MutexHandle
+{
+private:
+   void *mMutexPtr;
+
+public:
+   MutexHandle()
+      : mMutexPtr(NULL)
+   {
+   }
+
+   ~MutexHandle()
+   {
+      if(mMutexPtr)
+         unlock();
+   }
+
+   bool lock(void *mutex, bool blocking=false)
+   {
+      AssertFatal(!mMutexPtr, "MutexHandle::lock - shouldn't be locking things twice!");
+
+      bool ret = Mutex::lockMutex(mutex, blocking);
+
+      if(ret)
+      {
+         // We succeeded, do book-keeping.
+         mMutexPtr = mutex;
+      }
+
+      return ret;
+   }
+
+   void unlock()
+   {
+      if(mMutexPtr)
+      {
+         Mutex::unlockMutex(mMutexPtr);
+         mMutexPtr = NULL;
+      }
+   }
+
+};
+
+#endif // _PLATFORM_THREADS_MUTEX_H_