iokit/IOKit/IOCommand.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 /*
  24  *
  25  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  26  *
  27  *      HISTORY
  28  *
  29  *      2001-01-18 gvdl Made the primary queue pointer public, to be used when
  30  *                      Ownership is clear.
  31  *      11/13/2000 CJS  Created IOCommand class and implementation
  32  *
  33  */
  34
  35 /*!
  36  * @header IOCommand
  37  * @abstract
  38  * This header contains the IOCommand class definition.
  39  */
  40
  41 #ifndef _IOKIT_IO_COMMAND_H_
  42 #define _IOKIT_IO_COMMAND_H_
  43
  44 /*
  45  * Kernel
  46  */
  47
  48 #if defined(KERNEL) && defined(__cplusplus)
  49
  50 #include <kern/queue.h>
  51 #include <libkern/c++/OSObject.h>
  52
  53 /*!
  54  * @class IOCommand
  55  * @abstract
  56  * This class is an abstract class which represents an I/O command.
  57  * @discussion
  58  * This class is an abstract class which represents an I/O command passed
  59  * from a device driver to a controller. All controller commands (e.g. IOATACommand)
  60  * should inherit from this class.
  61  */
  62
  63 class IOCommand : public OSObject
  64 {
  65     OSDeclareDefaultStructors(IOCommand)
  66
  67 public:
  68     virtual bool init(void);
  69
  70 /*! @var fCommandChain
  71     This variable is used by the current 'owner' to queue the command.  During the life cycle of a command it moves through a series of queues.  This is the queue pointer for it.  Only valid while 'ownership' is clear.  For instance a IOCommandPool uses this pointer to maintain its list of free commands.  May be manipulated using the kern/queue.h macros */
  72     queue_chain_t fCommandChain;        /* used to queue commands */
  73 };
  74
  75 #endif /* defined(KERNEL) && defined(__cplusplus) */
  76
  77 #endif  /* _IOKIT_IO_COMMAND_H_ */