XnThreadSafeQueue.h

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/*****************************************************************************
*                                                                            *
*  OpenNI 1.0 Alpha                                                          *
*  Copyright (C) 2010 PrimeSense Ltd.                                        *
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#ifndef __XN_THREAD_SAFE_QUEUE_H__
#define __XN_THREAD_SAFE_QUEUE_H__

//---------------------------------------------------------------------------
// Includes
//---------------------------------------------------------------------------
#include <XnQueue.h>
#include <XnOS.h>

//---------------------------------------------------------------------------
// Types
//---------------------------------------------------------------------------
class XnThreadSafeQueue : public XnQueue
{
public:
        XnThreadSafeQueue() : m_hLock(NULL) {}

        ~XnThreadSafeQueue()
        {
                xnOSCloseCriticalSection(&m_hLock);
        }

        XnStatus Init()
        {
                XnStatus nRetVal = XN_STATUS_OK;

                nRetVal = xnOSCreateCriticalSection(&m_hLock);
                XN_IS_STATUS_OK(nRetVal);

                return (XN_STATUS_OK);
        }

        XnStatus Push(XnValue const& value)
        {
                XnStatus nRetVal = XN_STATUS_OK;

                nRetVal = xnOSEnterCriticalSection(&m_hLock);
                XN_IS_STATUS_OK(nRetVal);

                nRetVal = XnQueue::Push(value);
                xnOSLeaveCriticalSection(&m_hLock);

                return nRetVal;
        }

        XnStatus Pop(XnValue& value)
        {
                XnStatus nRetVal = XN_STATUS_OK;

                nRetVal = xnOSEnterCriticalSection(&m_hLock);
                XN_IS_STATUS_OK(nRetVal);

                nRetVal = XnQueue::Pop(value);
                xnOSLeaveCriticalSection(&m_hLock);

                return nRetVal;
        }

        XnUInt32 Size() const
        {
                xnOSEnterCriticalSection(&m_hLock);
                XnUInt32 nSize = XnQueue::Size();
                xnOSLeaveCriticalSection(&m_hLock);
                return (nSize);
        }

private:
        // NOTE: we declare the lock as mutable, as it may change on const methods.
        mutable XN_CRITICAL_SECTION_HANDLE m_hLock;
};

#define XN_DECLARE_THREAD_SAFE_QUEUE_WITH_TRANSLATOR_DECL(decl, Type, ClassName, Translator)    \
        class decl ClassName : public XnThreadSafeQueue                                                                         \
        {                                                                                                                                                                       \
        public:                                                                                                                                                         \
                ~ClassName()                                                                                                                                    \
                {                                                                                                                                                               \
                        /* We do this using Pop() to make sure memory is freed. */                                      \
                        Type dummy;                                                                                                                                     \
                        while (Size() != 0)                                                                                                                     \
                                Pop(dummy);                                                                                                                             \
                }                                                                                                                                                               \
                XnStatus Push(Type const& value)                                                                                                \
                {                                                                                                                                                               \
                        XnValue val = Translator::CreateValueCopy(value);                                                       \
                        XnStatus nRetVal = XnThreadSafeQueue::Push(val);                                                        \
                        if (nRetVal != XN_STATUS_OK)                                                                                            \
                        {                                                                                                                                                       \
                                Translator::FreeValue(val);                                                                                             \
                                return (nRetVal);                                                                                                               \
                        }                                                                                                                                                       \
                        return XN_STATUS_OK;                                                                                                            \
                }                                                                                                                                                               \
                XnStatus Pop(Type& value)                                                                                                               \
                {                                                                                                                                                               \
                        XnValue val;                                                                                                                            \
                        XnStatus nRetVal = XnThreadSafeQueue::Pop(val);                                                         \
                        if (nRetVal != XN_STATUS_OK) return (nRetVal);                                                          \
                        value = Translator::GetFromValue(val);                                                                          \
                        return XN_STATUS_OK;                                                                                                            \
                }                                                                                                                                                               \
        };

#define XN_DECLARE_THREAD_SAFE_QUEUE_WITH_TRANSLATOR(Type, ClassName, Translator)                               \
        XN_DECLARE_THREAD_SAFE_QUEUE_WITH_TRANSLATOR_DECL(, Type, ClassName, Translator)

#define XN_DECLARE_THREAD_SAFE_QUEUE_DECL(decl, Type, ClassName)                                                                                        \
        XN_DECLARE_DEFAULT_VALUE_TRANSLATOR_DECL(decl, Type, XN_DEFAULT_TRANSLATOR_NAME(ClassName))                             \
        XN_DECLARE_THREAD_SAFE_QUEUE_WITH_TRANSLATOR_DECL(decl, Type, ClassName, XN_DEFAULT_TRANSLATOR_NAME(ClassName))

#define XN_DECLARE_THREAD_SAFE_QUEUE(Type, ClassName)           \
        XN_DECLARE_THREAD_SAFE_QUEUE_DECL(, Type, ClassName)

#endif //__XN_THREAD_SAFE_QUEUE_H__