pxtimer.h

linux下的一款播放器

/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: pxtimer.h,v 1.2.52.3 2004/07/09 01:43:51 hubbe Exp $
 * 
 * Portions Copyright (c) 1995-2004 RealNetworks, Inc. All Rights Reserved.
 * 
 * The contents of this file, and the files included with this file,
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 * Source License (the "RPSL") available at
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 * the file under the current version of the RealNetworks Community
 * Source License (the "RCSL") available at
 * http://www.helixcommunity.org/content/rcsl, in which case the RCSL
 * will apply. You may also obtain the license terms directly from
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 * to this file, the RCSL.  Please see the applicable RPSL or RCSL for
 * the rights, obligations and limitations governing use of the
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 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL") in which case the provisions of the GPL are applicable
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 * This file is part of the Helix DNA Technology. RealNetworks is the
 * developer of the Original Code and owns the copyrights in the
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 * ***** END LICENSE BLOCK ***** */

#ifndef PXTIMER_H
#define PXTIMER_H

// Forward declarations
typedef _INTERFACE IHXCallback  IHXCallback;
typedef _INTERFACE IHXScheduler IHXScheduler;
class CHXBaseCountingObject;

class PXTimerResponse : public IUnknown
{
public:
    // IUnknown methods
    STDMETHOD(QueryInterface)   (THIS_ REFIID riid, void **ppvObj) PURE;
    STDMETHOD_(ULONG32,AddRef)  (THIS) PURE;
    STDMETHOD_(ULONG32,Release) (THIS) PURE;

    // PXTimerResponse methods
    STDMETHOD(TimerFire) (THIS_ UINT32 ulInstance) PURE;
};

class PXTimer : public CHXBaseCountingObject,
                public IHXCallback
{
public:
    PXTimer();
    virtual ~PXTimer();

    // IUnknown methods
    STDMETHOD(QueryInterface)   (THIS_ REFIID riid, void **ppvObj);
    STDMETHOD_(ULONG32,AddRef)  (THIS);
    STDMETHOD_(ULONG32,Release) (THIS);

    // IHXCallback methods
    STDMETHOD(Func)             (THIS);

    // PXTimer methods
    HX_RESULT Init(UINT32           ulInstance,
                   IUnknown*        pContext,
                   PXTimerResponse* pResponse);
    HX_RESULT StartTimer(UINT32 ulInterval);
    void      StopTimer();
    BOOL      IsStarted();
protected:
    enum
    {
        kStateConstructed,
        kStateInitialized,
        kStateActive,
        kMinInterval = 33
    };

    INT32            m_lRefCount;
    UINT32           m_ulState;
    UINT32           m_ulInstance;
    UINT32           m_ulInterval;
    IHXScheduler*   m_pScheduler;
    PXTimerResponse* m_pResponse;
    UINT32           m_ulCallbackHandle;
    BOOL             m_bCallbackPending;
    BOOL             m_bInsideTimerFire;

    void Deallocate();
    BOOL IsCallbackPending();
    void RemovePendingCallback();
};

inline BOOL PXTimer::IsCallbackPending()
{
    return m_bCallbackPending;
}

inline void PXTimer::RemovePendingCallback()
{
    if (m_bCallbackPending && m_pScheduler)
    {
        m_pScheduler->Remove(m_ulCallbackHandle);
        m_bCallbackPending = FALSE;
        m_ulCallbackHandle = 0;
    }
}

inline BOOL PXTimer::IsStarted()
{
    return (m_ulState == kStateActive ? TRUE : FALSE);
}

#endif