src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.h

/**************************************************************************
 *
 * Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * 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
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 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
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 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
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 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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/**
 * \file
 * Buffer fencing.
 * 
 * "Fenced buffers" is actually a misnomer. They should be referred as 
 * "fenceable buffers", i.e, buffers that can be fenced, but I couldn't find
 * the word "fenceable" in the dictionary.
 * 
 * A "fenced buffer" is a decorator around a normal buffer, which adds two 
 * special properties:
 * - the ability for the destruction to be delayed by a fence;
 * - reference counting.
 * 
 * Usually DMA buffers have a life-time that will extend the life-time of its 
 * handle. The end-of-life is dictated by the fence signalling. 
 * 
 * Between the handle's destruction, and the fence signalling, the buffer is 
 * stored in a fenced buffer list.
 * 
 * \author Jose Fonseca <jrfonseca@tungstengraphics.com>
 */

#ifndef PB_BUFFER_FENCED_H_
#define PB_BUFFER_FENCED_H_


#include "util/u_debug.h"


#ifdef __cplusplus
extern "C" {
#endif


struct pipe_fence_handle;


/**
 * List of buffers which are awaiting fence signalling.
 */
struct fenced_buffer_list;


struct pb_fence_ops
{
   void (*destroy)( struct pb_fence_ops *ops );

   /** Set ptr = fence, with reference counting */
   void (*fence_reference)( struct pb_fence_ops *ops,
                            struct pipe_fence_handle **ptr,
                            struct pipe_fence_handle *fence );

   /**
    * Checks whether the fence has been signalled.
    * \param flags  driver-specific meaning
    * \return zero on success.
    */
   int (*fence_signalled)( struct pb_fence_ops *ops,
                           struct pipe_fence_handle *fence,
                           unsigned flag );

   /**
    * Wait for the fence to finish.
    * \param flags  driver-specific meaning
    * \return zero on success.
    */
   int (*fence_finish)( struct pb_fence_ops *ops,
                        struct pipe_fence_handle *fence,
                        unsigned flag );
};


#ifdef __cplusplus
}
#endif

#endif /*PB_BUFFER_FENCED_H_*/