iokit/IOKit/IOCommand.h

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 /*
  32  *
  33  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  34  *
  35  *      HISTORY
  36  *
  37  *      2001-01-18 gvdl Made the primary queue pointer public, to be used when
  38  *                      Ownership is clear.
  39  *      11/13/2000 CJS  Created IOCommand class and implementation
  40  *
  41  */
  42
  43 /*!
  44  * @header IOCommand
  45  * @abstract
  46  * This header contains the IOCommand class definition.
  47  */
  48
  49 #ifndef _IOKIT_IO_COMMAND_H_
  50 #define _IOKIT_IO_COMMAND_H_
  51
  52 /*
  53  * Kernel
  54  */
  55
  56 #if defined(KERNEL) && defined(__cplusplus)
  57
  58 #include <kern/queue.h>
  59 #include <libkern/c++/OSObject.h>
  60
  61 /*!
  62  * @class IOCommand
  63  * @abstract
  64  * This class is an abstract class which represents an I/O command.
  65  * @discussion
  66  * This class is an abstract class which represents an I/O command passed
  67  * from a device driver to a controller. All controller commands (e.g. IOATACommand)
  68  * should inherit from this class.
  69  */
  70
  71 class IOCommand : public OSObject
  72 {
  73     OSDeclareDefaultStructors(IOCommand)
  74
  75 public:
  76     virtual bool init(void);
  77
  78 /*! @var fCommandChain
  79     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 */
  80     queue_chain_t fCommandChain;        /* used to queue commands */
  81 };
  82
  83 #endif /* defined(KERNEL) && defined(__cplusplus) */
  84
  85 #endif  /* _IOKIT_IO_COMMAND_H_ */