iokit/IOKit/IOCommand.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  *
  26  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  27  *
  28  *      HISTORY
  29  *
  30  *      2001-01-18 gvdl Made the primary queue pointer public, to be used when
  31  *                      Ownership is clear.
  32  *      11/13/2000 CJS  Created IOCommand class and implementation
  33  *
  34  */
  35
  36 /*!
  37  * @header IOCommand
  38  * @abstract
  39  * This header contains the IOCommand class definition.
  40  */
  41
  42 #ifndef _IOKIT_IO_COMMAND_H_
  43 #define _IOKIT_IO_COMMAND_H_
  44
  45 /*
  46  * Kernel
  47  */
  48
  49 #if defined(KERNEL) && defined(__cplusplus)
  50
  51 #include <kern/queue.h>
  52 #include <libkern/c++/OSObject.h>
  53
  54 /*!
  55  * @class IOCommand
  56  * @abstract
  57  * This class is an abstract class which represents an I/O command.
  58  * @discussion
  59  * This class is an abstract class which represents an I/O command passed
  60  * from a device driver to a controller. All controller commands (e.g. IOATACommand)
  61  * should inherit from this class.
  62  */
  63
  64 class IOCommand : public OSObject
  65 {
  66     OSDeclareDefaultStructors(IOCommand)
  67
  68 public:
  69     virtual bool init(void);
  70
  71 /*! @var fCommandChain
  72     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 */
  73     queue_chain_t fCommandChain;        /* used to queue commands */
  74 };
  75
  76 #endif /* defined(KERNEL) && defined(__cplusplus) */
  77
  78 #endif  /* _IOKIT_IO_COMMAND_H_ */